Scientia Iranica
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Scientia Iranicaendaily1Sat, 01 Jan 2022 00:00:00 +0330Sat, 01 Jan 2022 00:00:00 +0330Analysis of non-Newtonian fluid with phase flow model
http://scientiairanica.sharif.edu/article_22368.html
We considered a stagnation point of Non-Newtonian Fluid with Phase Flow Model over a stretching surface with slip conditions. Two types of the nanoparticle used, namely Cu and 〖Al〗_2 O_3 with base fluid H_2 O. Acceptable to theoretical study, the mathematical model has been constructed through flow assumptions. Partial differential equations are made by applying the boundary layer approximations on the momentum and energy equations. The suitable similarity transformations are applied to the partial equations which are converted into ordinary differential equations. These equations are solved by numerical scheme, namely BVP4C method. The involving physical parameters effect is shown by graphs and tables. Our work shows a good agreement with the decay literature. The expressions F''(0) and -&theta;'(0) achieve fewer values by hybrid nanofluid than that of nanofluid. Moreover F''(0) and -&theta;'(0) increase for large values of the dimensionless parameter (N) where as F'(&xi;) and &theta;(&xi;).increase for large values of &Phi;_2.Effects of heat and mass transfer on stagnation point flow of micropolar Maxwell fluid over Riga plate
http://scientiairanica.sharif.edu/article_22439.html
In this paper, we investigated the stagnation point flow of Maxwell viscoelasticity with incompressible based micropolar fluid over a Riga plate. The mathematical model has been constructed though micropolar fluid flows over Riga plate. The implement the boundary layer approximation, the system of partial differential equations is produced through momentum equation along with micro inertia theory. Nonlinear partial differential equations are become dimensionless nonlinear ordinary differential equations through suitable similarity transformations. This system is solved numerical scheme via BVP4C method. The effects of involving physical parameters like as dimensionless parameter, Modified Hartman number, Material parameter, Slip condition &sigma;_s, Viscoelastic parameter &delta;_m and Soret coefficient S_T are highlighted through graphs and numerical results. The physical quantities like as Skin friction, local Nusselt number and local Sher-wood number are highlighted through tables. R is increasing with increasing dimensionless parameter, Material parameter K and Slip condition &sigma;_s. R is decreasing with increasing behavior of Modified Hartman number Z and viscoelastic parameter &delta;_m.Green synthesis of Ag nanoparticles by methadone and their cytotoxicity against human breast cancer cells
http://scientiairanica.sharif.edu/article_22413.html
Recently, the preparation of silver nanoparticles (AgNPs) by green technique has improved due to their fundamental applications in medicine. In this study, methadone syrup (ME) was used for the preparation of AgNPs as a reducing and stabilizing agent with the aim of in vitro cytotoxicity effect against the human breast cancer cells. The characteristics of prepared particles are investigated by transmission electron microscopy (TEM), environmental scanning electron microscopy (ESEM), energy-dispersive X-ray spectroscopy (EDS), dynamic light scattering (DLS), UV&ndash;visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction studies (XRD). The AgNPs (about 18 nm) were synthesized in a spherical shape and uniform distribution. The mechanism of ME through the synthesis has been proposed based on FT-IR analysis and density functional theory. To investigate the cytotoxicity of prepared AgNPs by ME, MTT assay was used in the range of 0-100 &mu;g/mL. As a function of its dosage, the green synthetic AgNPs showed anti-proliferation activity against MDA-MB-468 cells respect to ME. The results demonstrated the feasibility of producing AgNPs in a simple, rapid, and green manner using ME, which has an important function in inhibiting the growth of breast cancer cells.The structural, optical, and self-cleaning properties of Mn3O4/SnO2 multilayer thin films deposited using spray pyrolysis technique
http://scientiairanica.sharif.edu/article_22441.html
Due to the wide applications of self-cleaning surfaces in various industries such as textile, automotive, construction, agriculture, optics, marine and aerospace industries, the development of self-cleaning coating production methods in a simple and inexpensive way has been considered by researchers. In this paper, Tin oxide (SnO2) and Manganese (II, III) oxide (Mn3O4) were prepared via sol&ndash;gel procedure. Next, (Mn3O4/ SnO2) double-layers were deposited using spray pyrolysis system on glass substrates. According to AFM images of Mn3O4 thin films, grains are tightly packed, entirely compressed and without crack. AFM images of SnO2 films indicated that the width of grain was about 242.8 nm and RMS roughness was about 25.85 mm. These images for bilayer demonstrated that the grain width was about 130-220 nm and root-mean-square thickness was about 20 mm. The SnO2 and Mn3O4 ﬁlms, and SnO2/Mn3O4 bilayer showed a direct optical band gap and hydrophilicity with water contact angle of 75◦, 31◦, and 70◦ respectively. Due to the importance and various applications of hydrophilic surfaces, in this research, thin layers of metal oxide were produced in a very simple way, among which the thin layer of Mn3O4 has good hydrophilicity.Transport of MHD nanofluid in a stratified medium containing gyrotactic microorganisms due to a stretching sheet
http://scientiairanica.sharif.edu/article_22429.html
In this article, an elaborated evaluation has been presented for the stratified MHD Jeffrey nanofluid flow towards a stretching surface in the presence of gyrotactic micro-organisms. The analysis of the flow by taking into consideration the viscous dissipation, Brownian motion, Joule heating and thermophoresis aspects. The governing nonlinear system of partial differential equations (PDEs), administering the flow, are turned to a group of the nonlinear ordinary differential equations (ODEs) via using an appropriate similarity transformation and later solved numerically by implementing the Keller-box approach with the help of algebraic software Matlab. The impacts of a variety of parameters on the fluid motion, heat, mass, density of the motile micro-organisms, skin friction, Nusselt number, Sherwood number and local density number of the motile micro-organisms are examined with the aid of graphs as well as tables. The results suggest that the motile micro-organisms density is a decreasing function of the Lewis number, Pecket number and microorganisms concentration difference. The Sherwood number and density rate of motile micro-organisms are bigger in the case of magnetic parameter and Lewis number. It is identified that temperature, density of nanoparticles and motile micro-organisms density stratification parameters lead to decrease the temperature and density of nanoparticles profiles.Antibacterial properties of zinc oxide nanoparticles on Pseudomonas aeruginosa (ATCC 27853)
http://scientiairanica.sharif.edu/article_22560.html
The involvement of nanotechnology has brought advancements in the environmentaland medical applications. Recently, zinc oxide nanoparticle (ZnO NP) is commonly used totreat a wide range of bacterial and fungal skin infections due to its antimicrobial property.This investigation was intended to study the antimicrobial effect of ZnO NP on Pseudomonasaeruginosa by testing the bacterial inhibition and the morphological damages caused by ZnONP on P. aeruginosa. The results of the study at 24 h exhibited a typical dose dependant andsignificant (p&gt; 0.05) inhibition on the growth of P. aeruginosa treated with 5 to 150 &mu;g/mLof ZnO NP. The polysaccharides and polypeptides from P. aeruginosa cell wall were found tobe associated to the attachment of ZnO NPs on bacterial cells as illustrated in the Fouriertransform infrared (FTIR) spectrum. Furthermore, the scanning electron microscopy (SEM)images displayed the surface attachment of ZnO NPs on bacteria and the morphologicalchanges such as disrupted cell wall integrity, cell bending and cell distortion as the result ofZnO NPs interaction on the cell wall of P. aeruginosa.Photocatalytic C-H bond activation by surface anchoring of [CoII(Saloph)(His)] complex on Ag-TiO2 nanocomposite
http://scientiairanica.sharif.edu/article_22354.html
A novel heterojunction plasmonic photocatalyst [Co(Saloph)(His)]/Ag-TiO2 as a nanohybrid material was applied for the photocatalytic activity towards the C-H bond cleavage of alcohols to the aldehyde using different oxidants, O2, H2O2, or TBHP under irradiation of visible-light and NHPI as co-catalyst. It was synthesized by photo-deposition of metallic silver nanoparticles on titanium oxide surface and follow it, modification with cobalt(II) Saloph complex under ultrasonic agitation condition using histidine linker to reach a photocatalyst under 50 nm in size and band gap 2.64 eV. The [Co(Saloph)(His)]/Ag-TiO2 nanohybrid was characterized with EDS, XRD, DRS, FT-IR, PL spectroscopies, FESEM imaging, and BET technique. The size This three-component plasmonic photocatalyst revealed high photocatalytic efficiency with 95% conversion and 99% selectivity in aerobic conditions. The higher photocatalytic performance of [Co(Saloph)(His)]/Ag-TiO2 than the Co(Saloph)/TiO2 and Ag-TiO2 NPs should be related to the localized surface plasmonic resonance (LSPR) of these motives. So, this three-component nanohybrid provides an efficient interfacial electron transfer process through a synergistic effect that allows producing a nanocatalyst, with advantages of stability and fast selective C-H bond activation alcohols at ambient temperature using O2 as an inexpensive environmental friendly oxidant.Study of anticorrosion properties of epoxy-nano alumina/nano chitosan nanocomposite coating
http://scientiairanica.sharif.edu/article_22352.html
In this research, the anticorrosion properties of epoxy-based nanocomposite coating were studied using the Taguchi statistical method. A L16 orthogonal array with the four factors of control at four levels each and two interactions was employed for preparation of nanocomposite coating by adding chitosan nanoparticles and alumina nanoparticles in various concentrations, temperatures and mixing times. The analysis of variance and signal-to-noise ratio showed the film coating for steel panels significantly increases the anticorrosion properties. The optimal conditions for preparation of nanocomposite coating were obtained alumina nanoparticles 2%, chitosan nanoparticles 2%, temperature of 20 &deg;C and a mixing time of 30 minutes. Finally, the surface of the coating film was analyzed by SEM.Three-dimensional repositioning of jaw in the orthognathic surgery using the binocular stereo vision
http://scientiairanica.sharif.edu/article_4351.html
In recent years, the binocular stereo vision has become more popular in many different areas because of the latest developments in three-dimensional (3-D) image processing technology that ensures rich information in comparison with other sensor types. This study presents a novel method based on the binocular stereo vision system to reduce the measurement error encountered frequently in the orthognathic surgery.&nbsp; The main aim is to enhance the level of the accuracy of this sensitive operation. The developed system is not only useful for the preoperative assessment or the postoperative process but also can be utilized during the real-time operation. Additionally, this system provides a broader working field, more practical and healthier environment and less expensive setup. Therefore, the developed binocular stereo vision system may be acceptable for most surgeons. Experimental results show that the average error rate for all of X, Y and Z coordinates in the Cartesian system is 0.25 mm which is clinically acceptable (&lt; 1.00 mm). The binocular stereo vision system would be a helpful throughout the orthognathic surgery to improve precision of the measurement and satisfy the healthy surgical operating environmentA Novel Similar Character Discrimination Method for Online Handwritten Urdu Character Recognition in Half Forms
http://scientiairanica.sharif.edu/article_20826.html
Online handwritten Urdu character recognition is one of the key technologies for intelligent interface on smart phones and touch screens. It is a challenging research topic as Urdu script has many similar character groups. A novel similar character discrimination method for online handwritten Urdu character recognition is proposed in this paper which includes pre-classification, feature extraction and fine classification process. The pre-classifier enables the discrimination of similar characters by putting them in distinct smaller subsets according to stroke number and diacritics. Then structural features and wavelet features are extracted. Finally, Support Vector Machines (SVM), Artificial Neural Networks (ANN), and Recurrent Neural Network (RNN) classifiers are compared for fine classification within subsets. Results of RNN classifier without using the proposed pre-classifier and features have also been obtained to check the end-to-end capability of the RNN classifier. Experimental results show that the proposed method is efficient and achieves an overall accuracy of 96% on a large-scale self-collected dataset. It is feasible to extend this method for other Arabic scripts.A STUDY ON REPAIRING PROCEDURES INVOLVED WITH LEADING EDGE CRACKS, OFFSETTING, OVERBITE & UNDERBITE OF GLASS FABRIC REINFORCED COMPOSITE BASED WIND TURBINE BLADES
http://scientiairanica.sharif.edu/article_21313.html
Rotor blades are the most important part of wind turbine system, which are generally made up of polymer matrix based composites. The performance and lifetime of the wind turbine system often depend of the constituent of composite materials, properties of these materials, design of blades and manufacturing techniques. However the inspections after manufacturing of blades do reveal certain defects which need to addressed and fixed before it is sent for real time operations. Further offsetting usually occurs when closure of two blade halves lead to displacement of aerodynamic suction side from the aerodynamic pressure side. This work is concerned with the two main objectives: one is to repair leading edge cracks in the longitudinal direction, outside the area with existing external root over lamination, the second objective is to how offsetting is measured, evaluated and repaired especially in connection with: overbite and underbite. All these repair procedures were conducted on the glass fabric reinforced polyester blades manufactured by Hand lay-up technique. Until aforementioned repair procedures are not performed, the blades will not be sent to assembly stage. Ultrasonic inspection was conducted as per ASTM standards, ASTM E317 and ASTM E1316.Polygonal Tubular Linear Permanent Magnet Generator Analysis and Experimental Test
http://scientiairanica.sharif.edu/article_21539.html
Free piston generators are of interest due to their efficiency,compact construction, homogeneous nature,and multiple options for combustion.Much of the research into this type of generator has been facilitated by highly-developed internal combustion engine technology.This study was concerned with the design and application of tubular generator.The design model was developed using the matrix laboratory graphical user interface (MATLAB GUI) programming tool, and the designed interface was of the dynamic type.The sizing of the generator was determined in accordance with the main parameters specified via the interface. In addition, as a benefit of using sizing data, the automatic geometry was formed and analyzed using ANSYS Maxwell software.The magnets and the dynamic part of the tubular-structured generator were shaped polygonally.Numerical analyses were made by adopting the finite element method in the software, and construction of the prototype model was based on the results from these findings.The generator was excited by use of the crank rod mechanism to imitate the conditions of a functioning free piston mechanism.Current and voltage values were obtained at mechanical frequencies of 10Hz and 20Hz, and this data was subsequently analyzed.Global code translation was given in attachment in order to allow communication between the ANSYS Maxwell and MATLAB GUI software.A Dual- Stator Machine with Diametrically Magnetized PM: Analytical Air-gap Flux Calculation, Efficiency Optimization and Comparison with Conventional Dual-Stator Machines
http://scientiairanica.sharif.edu/article_21545.html
This paper presents a design and optimization procedure for a dual-stator machine with a diametrically magnetized PM to improve the electromagnetic performance. First, analytical design equations are presented based on MEC analysis; they are used to design a basic dual-stator machine. Then, by applying an artificial intelligence algorithm, the machine is optimized to achieve high efficiency and torque density, and low pulsating torque for direct-drive applications. A quantitative comparison is performed between the optimized new machine and conventional dual-stator machines to evaluate the performances and improvements of the understudy machine. The machine performance, including air-gap flux density distribution, back electromotive force, electromagnetic torque, cogging torque, and torque ripple are analyzed by the finite element method. The analysis results have demonstrated that benefiting from its topology, the optimized dual-stator machine with diametrically magnetized PM has the comprehensively better performance, including higher torque density, higher efficiency, and lower torque ripple and cogging torque compared to conventional dual-stator machines.An incentive-based policy on reduction of GHG emissions and loss minimization using adaptive group search multi-objective optimization algorithm
http://scientiairanica.sharif.edu/article_21546.html
A transactive strategy to purposeful pricing distributed energy resources (DERs) in distribution networks is proposed in this paper. This strategy is presented as a novel heuristic optimization approach. The total network loss and released greenhouse gases (GHGs) emissions are considered as objective functions. In addition, the locational marginal prices (LMPs) and power factors of DERs are considered as decision variables. Each DER, which is more participated in the mitigation of afore-mentioned objectives, will contribute a larger excitement form benefits consequently. Therefore, more contribution consequent to more generation leads to a higher price for DERs bus in comparison to substation market price. Also, the earned benefits from loss/emission mitigations are allocated to DERs directly. The fairness of this pricing process is supervised by the Independent Distribution System Operator (IDSO). Because the problem has two contradictory objective functions, a reliable Multi-Objective method called Chaotic search and Covariance matrix (MGSOACC) is proposed to solve the problem. To evaluate the proposed method, the pricing procedure is applied on modified IEEE-33 and IEEE-69 bus test networks. Furthermore, in order to the validation of the proposed optimization method, the result-oriented comparisons between four conventional Multi-Objective optimization methods and proposed optimization method are presented.Control and stability analysis of VSC-HVDC based transmission system connected to offshore wind farm
http://scientiairanica.sharif.edu/article_21556.html
Offshore wind farms (WFs) with significant capacities have been installed recently all over the world. In order to transmit the WF power to the onshore grid, high voltage direct current (HVDC) transmission system is appropriate technology. This paper analytically studies the impact of system parameters, controllers and operating conditions on the dynamic behavior of HVDC transmission systems based on three-level neutral point clamped voltage source converters (VSC). Also, it investigates modeling, control and stability analysis of VSC-HVDC system connected to the offshore wind farms. The VSC-HVDC system comprises offshore and onshore converters and high voltage dc transmission lines. The paper extracts VSC-HVDC system dynamics at the dc-side and argues the interaction between onshore converter control and HVDC transmission line dynamics. Moreover, the paper presents controller design for the dc-link voltage regulation by the onshore converter and examines the impacts of HVDC line length and dc voltage control bandwidth (BW) on the system stability by the modal analysis and time domain simulations.A Comparative Analysis of The New Excitation Controlled Synchronous Generator-Based Wind Turbine
http://scientiairanica.sharif.edu/article_21559.html
Excitation Controlled Synchronous Generator-based Wind Turbine (ECSG WT) is a recently proposed wind turbine scheme which has not been fully investigated in detail. This paper is devoted to analyze performance of the ECSG WT scheme and to compare it with two mainstream wind turbine schemes based on electrically excited synchronous generator, i.e. VSC-based full converter wind turbine and diode bridge rectifier-based wind turbine equipped with boost converter on its DC link. The aim of this comparison is to demonstrate great potentials of ECSG WT for being considered in wind industry. To do so, two successful WT schemes at the market which are structurally close to ECSG WT are selected. The comparison includes different technical and economic aspects of the three schemes, assuming DC grid connection for the wind turbines. In addition, another comparison is made between the recently introduced Siemens 2nd generation DC Grid Access Offshore wind farm and a wind farm with similar structure, but using ECSG WTs. The results of these comparisons declare that ECSG WT scheme has promising characteristics, especially regarding economic, reliability and efficiency aspects.Design and Optimization of a Large-Scale Permanent Magnet Synchronous Generator
http://scientiairanica.sharif.edu/article_21561.html
Direct drive permanent magnet synchronous generators have numerous advantages such as improved reliability, low maintenance, long life, and developed performance characteristics. Focus of this paper is on the development of a step-by-step method for the design of a permanent magnet synchronous generator. Then the winding function method is used to model the generator and to analytically calculate its output characteristics. The analytical results of the designed generator are evaluated with the finite element analysis (FEA) results and it is demonstrated that the achieved results from both methods are well matched with the experimental measurements of the Northern Power direct-drive generator. The sensitivity analysis and the optimization based on the genetic algorithm are used to achieve an optimum generator. The optimization goal is obtaining higher efficiency and power factor with lower required permanent magnet (PM) volume and voltage regulation for the optimum machine compared to the initial design. In addition, the calculation of the voltage total harmonic distortion (THD) is presented and the optimum skew angle for the optimum generator is computed to reduce the voltage THD.On the well-posedness, equivalency and low-complexity translation techniques of discrete-time hybrid automaton and piecewise affine systems
http://scientiairanica.sharif.edu/article_21594.html
The main contribution of this paper is to present the systematic and low-complexity translation techniques between a class of hybrid systems referred to as automaton-based DHA and piecewise affine (PWA) systems. As an starting point the general modeling framework of the automaton-based DHA is represented which models the controlled and uncontrolled switching phenomena between linear continuous dynamics including discrete and continuous states, inputs and outputs. The basic theoretical definitions on the state trajectories of the proposed DHA with forward and backward evolutions which yield forward and backward piecewise affine (FPWA and BPWA) systems are given. Next, the well-posedness and equivalency properties are proposed and the sufficient conditions under which the well-posedness property is achieved with the automaton-based DHA and PWA systems are given. It is shown that the graphical structure of the proposed automaton-based DHA makes it possible to obtain analytically the equivalent PWA system with a polynomial complexity in contrast to the existing numerical translation techniques via decomposed structure of the DHA with an exponential complexity. Examples are presented to confirm the effectiveness of the proposed translation techniques.Expansion Planning of Automated Sub-transmission and Distribution Networks integrated by Distributed Generations
http://scientiairanica.sharif.edu/article_21666.html
This paper presents sub-transmission and distribution network expansion planning (S&amp;DEP) including distributed generation (DG) and distribution automation (DA) considering reliability indexes. The objective function is to minimize investment, operation, maintenance and reliability costs subjected to AC power flow, system operation and generating units and DG limits, reliability, and distribution automation constraints (including the constraints of protection devices and volt/VAr control mechanism). The proposed model is a mixed integer non-linear programming (MINLP) model which is hard to solve. For this reason, a MINLP problem is transformed to mixed integer linear programming (MILP) model. The validity of the proposed method is investigated in the two synthetic test networks.Designing and analyzing two non-invasive current sensors using Ampere Force Law (AFL)
http://scientiairanica.sharif.edu/article_21670.html
Here two different non-invasive current sensors are proposed, modeled and analyzed. The current sensors are based on the Ampere Force Law (AFL), defining the magnetic force between two parallel wire carrying currents. These current sensors can be used for detecting/sensing DC and AC currents as well as their combination in a single wire or multiple wires, and they do not rely on any permanent magnets for operation. In the first configuration, there are two microbeams, in which one of them is at the vicinity of the wire and undergoes the mechanical vibrations due to magnetic force between the wire and the microbeam. The movement of the microbeam while it is generating a magnetic field induces a current inside the another microbeam, which is stationary, as the output signal of the current sensor. In the second configuration, a single composite piezoelectric microbeam is used. The magnetic force between the wire and the piezoelectric microbeam leads the piezoelectric microbeam to move, thus it produces a voltage. Both configurations present an extremely low power consumption, which is not dependent on the sensitivity of the current sensors. The dynamic response, sensitivity and power consumption of the current sensors are investigated, compared and discussed.Tuning the Implementable Structures of Fractional-Order PID Controllers for Control of FOPDT Processes
http://scientiairanica.sharif.edu/article_21686.html
This study presents a set of rules for optimal tuning a class of integer-order controllers, known as implementable fractional-order PID controllers, to be applied in control of first-order-plus-dead-time (FOPDT) processes. To this aim, the approach of so-called &ldquo;tuning based on the implementable form of the controller&rdquo; is applied instead of the common approach of &ldquo;tuning based on the ideal form of the controller&rdquo;. Consequently, no contradiction is found between the behavior of the tuned controller and that of the implemented controller. Also, algebraic relations between the values of cost functions, which are defined based on integral square error (ISE) and integral square time error (ISTE) performance indices, and free parameters of the implementable controller are established. Tuning implementable fractional-order PID controllers via the proposed rules guarantees that the values of performance indices are reduced in comparison with the case of using optimal PID controllers. In addition to numerical results, experimental results are also provided to demonstrate the effectiveness of the proposed tuning rules in practical applications.Tunable Active Grounded Lossless and Lossy Inductance Simulators with Single Grounded Capacitor Using VDBAs
http://scientiairanica.sharif.edu/article_21694.html
In this paper, three active-C synthetic grounded inductance simulator circuits are presented, which realize tunable lossless and lossy series and parallel RL-type inductances. Each of which employs two voltage differencing buffered amplifiers (VDBAs) as active components, and a single grounded capacitor as a passive component. In all the proposed circuits, the simulated equivalent resistance and inductance values can be adjusted electronically through the transconductance gains of the VDBAs. They also do not require any critical component matching conditions and cancellation constraints. Detail non-ideal analysis including transfer errors of the VDBA has been analyzed. For circuit performance verification and comparison, some application examples are given together with computer simulation results by PSPICE program.Electricity Market Assessment in Wind Energy Integrated Power Systems with the Potential of Flexibility: A Boundary Condition Approach
http://scientiairanica.sharif.edu/article_21697.html
This paper focuses on a dynamic equilibrium considering the flexible ramp market and demand response resources. With ever-swelling installation of variable renewable energies, demand response programs can play an important role in mitigating the system ramping deficiency. Hence in this paper, the ramping capability of demand response resources in procuring system ramp requirement is considered. The strategic behavior of different players is modeled through a multi-leader-common-follower game, in which suppliers and demand response aggregators are laid as the leaders and market operator is considered as the single follower of the game. In addition, a dynamic forward rolling process to find equilibria at the real-time market is proposed. The effect of considering demand response resources and flexible ramp penalty price on the strategic behavior of players in equilibrium is evaluated. Finally, the effectiveness of the proposed approach is verified on a three-firm system. While revealing demand response resources roles in mitigating ramping deficiency, the results show that how penalty price on flexible ramp violation can lead uplift payments to be formed.Investigation of Harmonic Effects in Locational Marginal Pricing and Developing a Framework for LMP Calculation
http://scientiairanica.sharif.edu/article_21735.html
Locational Marginal Pricing (LMP) is arguably the most effective and commonly employed mechanism to provide the most reliable economic signal to market participants. Meanwhile, nodal prices depend on active power losses and transmission congestion which may be affected by harmonics pollution. In the conventional method, power system and loads are assumed linear and nodal prices are obtained by results of optimal power flow (OPF) at the power frequency. Harmonics lead to skin effect and increasing loss. Further, harmonic flowing in branches in a power network occupies transmission capacity. For providing more accurate signals to market participants and achieving more accurate nodal prices, harmonic effects on LMP are investigated and a framework is developed for LMP calculation in a harmonic polluted power system. In this framework, skin effect, losses, and congestion which can be arisen by harmonic pollution are modelled in optimal power flow (OPF) and are considered in LMP calculation. The proposed concept is implemented with 9-bus and 30-bus test systems while nodal price changes are also indicated.A Combined Benders Decomposition and Lagrangian Relaxation Algorithm for Optimizing a Multi-Product, Multi-Level Omni-Channel Distribution System
http://scientiairanica.sharif.edu/article_21774.html
The development of supply chain distribution systems from single- to multi-channel networks for delivering items to end customers has effected many changes in the retail sector. Following the adoption of multi-channel distribution strategies and rapid development of relevant technologies, the Omni-channel approach can yield significant benefits and facilitate trade with customers. This paper aims to optimize a multi-product, multi-level Omni-channel distribution network and shipping flows of products within the network under uncertain conditions. A multi-objective mathematical model is developed that minimizes the costs of supply chain while maximizing customer satisfaction over different scenarios. In order to solve the proposed model, a combined algorithm is developed based on Benders Decomposition (BD) and Lagrangian Relaxation (LR). The presented model and solution approach is implemented in a case study of a distribution system, a large e-commerce startup and online store. Five different scenarios with various service levels are investigated and the numerical results are discussed compared to previous findings. The efficiency of the proposed combined BD-LR solution algorithm is also demonstrated. The results obtained from the case study show that higher service levels are correlated with higher levels of customer satisfaction and lower cost of the system.A two-echelon newsvendor problem with limited budget and capacity
http://scientiairanica.sharif.edu/article_21778.html
In this paper, two-echelon newsvendor problem is considered. Many real-life situations like fashion, food industries, and healthcare services match newsvendor problem. Our problem is determining levels of inventory in order to optimize the profit and service level in selling a product. This product is made up of several raw materials. Only the distribution of demand is known, and the hot season of selling the product is just a short period and after that, the price of the product drops dramatically. The storage space and initial budget are limited. We modeled and solved the problem as an unconstrained nonlinear optimization problem using two nonlinear techniques, the sequential unconstrained minimization technique (SUMT) and steepest descent (SD).Optimal Design and Analysis of a Novel Reluctance Axial Flux Magnetic Gear
http://scientiairanica.sharif.edu/article_21781.html
This paper proposes modelling and optimization of a new reluctance axial flux magnetic gear (RAMG) with stationary outer rotor and advantages of lower permanent magnet usage. Due to the less use of the PMs, this structure has a higher economic interest, more reliability, and very simple and robust structure than its conventional ones. Gear ratio and operating principles are extracted and verificated using 3-D finite element method (FEM) simulations. Finally, a parametric optimization is done based on effective dimensions in design procedure with maximum torque density objective function. The magnetic flux distributions of optimized RAMG are calculated by 3-D FEM, as well as static and dynamic magnetic torques are derived correspondingly.Difference-Type-Exponential Estimators Based on Dual Auxiliary Information Under Simple Random Sampling
http://scientiairanica.sharif.edu/article_21789.html
Auxiliary information plays a vital role at the selection and/or estimation stage to achieve the efficient estimates of the unknown population parameters. Dual use of auxiliary information, one the original and second the ranks of the auxiliary variable help to increase the efficiency of the estimators. In this article, we proposed and evaluated the performance of difference-type-exponential estimators based on dual auxiliary information for population mean under simple random sampling. Mathematical expressions for the bias and the mean squared error of the proposed estimators are obtained. Three real-life data sets and Monte Carlo simulation studies are carried out for illustration. The results of the empirical and the simulation studies, in terms of mean square errors and percentage relative efficiencies indicate that the proposed estimators perform better as compared to their counterparts.Research on Impact of Shenzhen-Hong Kong Stock Connect Mechanism on the Volatility of Stock Markets
http://scientiairanica.sharif.edu/article_21805.html
The implementation of the Shenzhen-Hong Kong Stock Connect (SHSC) mechanism has realized the largest two-way opening of China's capital market, but also increased the transmission of risks. In order to analyze the impact of SHSC on the volatility of single market in Shenzhen or Hong Kong, this paper establishes the volatility models of stock markets in Shenzhen and Hong Kong based on the GARCH-type models with different perturbation terms. The pre-applicable test is made and the result shows that the return rate series of Shenzhen and Hong Kong stock markets are stable and heteroscedastic, and they meet the conditions of establishing the GARCH-type models. Then, the GARCH model and EGARCH model are established to analyze the volatility of stock markets in Shenzhen and Hong Kong respectively. The results show that the opening of SHSC has increased the short-term volatility of the stock markets in Shenzhen and Hong Kong and improved the efficiency of information transmission between these two stock markets. Moreover, influenced by SHSC, the leverage effect of Shenzhen stock market is increasing, while that of Hong Kong stock market is decreasing.A comparative study of Economic Load Dispatch with complex non-linear constraints using Salp Swarm Algorithm
http://scientiairanica.sharif.edu/article_21817.html
Economic Load Dispatch (ELD) is an important part of cost minimization procedure in power system operation. Different derivative and probabilistic methods are used to solve ELD problems. This paper proposes a powerful Salp Swarm Algorithm (SSA) to explain the ELD issue including equality and inequality restrictions. The main aim of ELD is to satisfy the entire electric load at minimum cost. The SSA is a population based probabilistic method which guides its search agents that are randomly placed in the search space, towards an optimal point using their fitness function and also keeps a track of the best solution achieved by each search agent. SSA is being used to solve the ELD problem with their high exploration and local optima escaping technique. This algorithm confirms that the promising areas of the search space are exploited to have a smooth transition from exploration to exploitation using the movement of Salps in the sea. Simulation results prove that the proposed algorithm surpasses other existing optimization techniques in terms quality of solution obtained and computational efficiency. The final results also prove the robustness of the SSA.Robust optimization approach for pricing and shelf space decisions with uncertain demand
http://scientiairanica.sharif.edu/article_21818.html
Pricing and shelf space allocation are two main operational decisions in retailing industry. This study simultaneously optimizes these two decisions in a supply chain with two manufacturers and one retailer under uncertainty of demand and price sensitivity parameters. Two manufacturers have different conditions in terms of parameters affecting demand and production. A robust optimization model and an exact solution approach are developed to find the optimal solution. The results show that price sensitivity, market potential and production costs can have a synergistic effect on optimal values. Moreover, the market potential can be relied on in managerial decisions as it has significantly positive impact on profitability. This parameter is found to be the most important tool for securing profitability of supply chain members.Efficient Estimation of Population Median Using Supplementary Variable
http://scientiairanica.sharif.edu/article_21819.html
In this paper, we propose an exponential cum ratio-product type estimators for population median (M_y) under simple random sampling scheme (SRS). The expressions of bias and mean square error (MSE) are obtained up to first order of approximation. The proposed estimators is more efficient as compared to all other considered estimators under certain conditions. Both numerical and simulation studies show that the proposed estimators perform better as compared to all other considered estimators. Four real data sets and simulation studies are carried out to observe the performances of the estimators. It is observed that the proposed estimators is perform more efficient in all situations.An Optimal Radiation Pattern Synthesis and Correction of Mutually Coupled Circular Dipole Antenna Array
http://scientiairanica.sharif.edu/article_21820.html
Abstract &ndash; This paper proposes a fundamental approach for radiation pattern correction of the mutually coupled circular dipole antenna array (CDAA) using parametric assimilation technique. The effect of mutual coupling is an indispensable part of any practical design issue of the antenna array. Many analytical and numerical techniques have been put forward in the past few decades for the calculation, compensation and reduction of mutual coupling effect. This paper shows an accurate method for mutual coupling correction by using a recently proposed technique called parametric assimilation technique, where the values of mutual impedance are calculated and assimilated with the values of the desired radiation pattern. The proposed technique is cost-effective, less complicated and easy to implement while achieves better performance for mutually coupled circular dipole antenna array synthesis. Grey Wolf Optimization (GWO) algorithm is a state-of-the-art stochastic algorithm applied here to find the optimal values of the current excitation weights and the inter-element spacing between each element of the CDAA for the desired, uncorrected and corrected far-field radiation pattern synthesis. PSO and DE optimization-based statistical results are also reported to compare the results obtained by using GWO algorithm to confirm the outstanding performance of GWO algorithm based design.Optimizing two multi-echelon inventory systems for perishable products with price and stock dependent demand in supply chain
http://scientiairanica.sharif.edu/article_21827.html
In this paper, two inventory models with starting shortages and without shortages for perishable products in supply chain are proposed. The demand for perishable products is dependent on price and stock. Supply chain is composed of one manufacturer, one distribution center, and one retailer. The objective of these two models is to maximize the average profit per unit time by determining the optimal replenishment cycle, frequency, and quantity. The property of optimal solutions for two cases of two models is discussed to verify the existence of optimal solutions. Algorithms for searching optimal solutions are presented. In order to investigate the effect of parameters on optimal solutions and obtain some management insights, computational experiments with sensitivity analyses are carried out. Finally, conclusions and future researches are provided.Environmental effects in an integrated hub location and pricing problem
http://scientiairanica.sharif.edu/article_21828.html
The product pricing decision is one of the important factors in the profitability of organizations, which has a key role in their survival. Moreover, the pricing is determined based on the demand and location of applicants. Therefore, the location of facilities and services influence the pricing. Also, the location problem is a critical issue in the survival of the organization. Furthermore, the hub location problem is a type of location problems, which has many applications and saves time and money. On the other hand, location is impossible without considering transportation and transportation has many negative effects on environmental, such as greenhouse gas emissions, air pollution, noise, etc. Considering this reason, it is important to consider the environmental costs to reduce the adverse effects. In this paper, we consider integrated pricing and hub location problem with environmental costs in the competitive market that customer choice is calculated according to the logit model (LM). We use a genetic algorithm (GA) to solve and observe the environmental cost, entrant profit, incumbent income, the impact of customer sensitivity and discount between hubs on the entrant profit. As a final point, the computational experiments demonstrate that the suggested GA is both efficient and effective.Security constrained optimal power flow in a power system based on energy storage system with high wind penetration
http://scientiairanica.sharif.edu/article_21829.html
This study is focused on assessing the effect of energy storage system (ESS) presence on security improvement of power systems hosting remarkable renewable energy resources. To this end, ESS presence is suitably included in security-constrained optimal power flow (SCOPF) model; the required technical amendments are hence considered. To launch a realistic model, ramping constraints of thermal units are also taken into account which limit the generators from completely responding to power shortfalls. Considering a high penetration level of renewable generations, different scenarios of outages in transmission lines and generators are simulated to measure the line outage distribution factor (LODF) and power transfer distribution factor (PTDF). also, in order to illustrate the economic impact of wind power generation curtailment and load shedding, two penalty parameters VWC and VOLL are considered in the model. Two test systems, including a PJM 5-bus system and an IEEE 24-bus RTS, are put under numerical studies to assess the possible impact of ESS on security improvement of the investigated systems. The obtained results are discussed in depth.Application of grey correlation-based EDAS method for parametric optimization of non-traditional machining processes
http://scientiairanica.sharif.edu/article_21830.html
Higher dimensional accuracy along with better surface finish of various advanced engineering materials has turned out to be the prime desideratum for the present day manufacturing industries. To achieve this, non-traditional machining (NTM) processes have become quite popular because of their ability to produce intricate shape geometries on diverse difficult-to-machine materials. To allow these processes to operate at their fullest capability, it is often recommended to set their different input parameters at the optimal levels. Thus, in this paper, a new technique combining grey correlation method and evaluation based on distance from average solution is applied for simultaneous optimization of three NTM processes, i.e. photochemical machining process, laser-assisted jet electrochemical machining process and abrasive water jet drilling process. The derived optimal parametric combinations outperform those as identified by the other popular multi-objective optimization techniques with respect to the considered response values. The results of analysis of variance also identify the most influencing parameters for the said NTM processes. Finally, the developed surface plots would help the process engineers in investigating the effects of different NTM process parameters on the corresponding grey appraisal scores.A branch oriented active power loss allocation method for radial distribution networks with distributed generators
http://scientiairanica.sharif.edu/article_21831.html
The penetration of distributed generation (DG) units in the radial distribution network (RDN) introduces complexity in active power loss allocation (LA) as it leads to reverse current in the network. This current makes power system bidirectional and brings difficulties in the decomposition of cross-terms of power loss equation. To overcome such complications, this paper proposes a new branch oriented LA technique which eliminates the impact of mutual-term mathematically from loss formulation without any assumptions and approximations. It establishes a direct relationship between the subsequent load currents of a branch and its two end voltages in terms of the complex power available at its load ends. The proposed LA scheme is found to be fair as regard to the topology of the RDN. Further, the implementation of DGs may increase/decrease power loss of a system. In order to provide the exact amount of loss reduction benefit to the DG owners (DGOs), a new DG remuneration strategy is developed in this paper which assigns either rewards/penalties to the DGOs after analysing their actual impact towards system loss reduction. The effectiveness of the proposed LA method is investigated against various established LA techniques using two different test systems i.e., 17-bus and 33-bus RDNs.Integration of Multi-mode Resource-Constrained Project Scheduling under bonus-penalty policies with Material Ordering under Quantity Discount scheme for minimizing project cost
http://scientiairanica.sharif.edu/article_21832.html
In this paper a mixed binary integer mathematical programming model is developed for integration of Multimode Resource-Constraint Project Scheduling Problem (MRCPSP) under bonus&ndash;penalty policies and Quantity Discount Problem in Material Ordering (QDPMO) with the objective of minimizing the total project cost. By proving a theorem, an important property of the optimum solution of the problem is found which reduces the search space significantly compared to previous studies. Since the RCPSP belongs to the class of problems that are NP-hard, four hybrid meta-heuristic algorithms called COA-GA, GWO-GA, PSO-GA and GA-GA is developed and tuned to solve the problem. Each of the proposed algorithms consists of outside and inside search components, which determine the best schedule, and materials procurement plan respectively. Finally a set of standard PROGEN test problems is solved by the proposed hybrid algorithms under fixed CPU time. The results show that the COA-GA algorithm outperforms others.Performance and dynamic response enhancement of PMSG based wind turbines employing boost converter-diode rectifier as the machine-side converter
http://scientiairanica.sharif.edu/article_21833.html
Wind turbines (WTs) with Permanent magnet synchronous generator (PMSG) are mostly integrated in power systems as popular energy conversion systems. From the machine-side converter (MSC) structure point of view, there are two types of PMSG-WTs: PMSG-WT with voltage source converter (VSC) as the MSC, and PMSG-WT with boost converter-diode rectifier as the MSC. The focus in this paper is on the control modification and dynamic and transient behavior improvement of PMSG-WTs with boost converter-diode rectifier. In this way, inner control loop of the boost converter current and outer control loop of generator speed are developed and extracted. Next, the boost converter control loop is modified by adding two auxiliary control signals, known as auxiliary damping signal and auxiliary compensation signal. The auxiliary damping signal modifies the boost converter current and provides a damping torque for inhibition of WT torsional oscillations. On the other hand, the auxiliary compensation signal, as the second auxiliary signal, limits the dc-link overvoltage during the voltage dip and amends the WT low voltage ride through capability. By modifying the wind turbine control through second auxiliary signal, the size, cost and rated energy of the required dc chopper resistance decrease considerably.Complex q-Rung Orthopair Fuzzy Variation Co-efficient Similarity Measures and their Approach in Medical Diagnosis and Pattern Recognition
http://scientiairanica.sharif.edu/article_21834.html
The q-rung orthopair fuzzy set (q-ROFS) as a generalization of fuzzy set (FS), is characterized by membership and non-membership, and the sum of their q-powers is restricted to [0,1]. In this manuscript, a new Complex q-rung orthoapir fuzzy set (Cq-ROFS) is proposed by combining q-ROFS and complex fuzzy set (CFS). Cq-ROFS is a better way to process uncertain and imprecise information in decision making, which is characterized by complex-valued membership and complex-valued non-membership. First, some fundamental operational laws, score function and accuracy function, and comparison method are proposed. Further, because the vector similarity measures (VSMs) play a key role in statistics, physics and engineering sciences, some VSMs called Jaccard similarity measures (JSMs), dice similarity measures (DSMs) and cosine similarity measures (CSMs) for Cq-ROFSs and interval-valued complex q-rung orthopair fuzzy sets (IVCq-ROFSs) are investigated. Moreover, the hybrid vector similarity measures (HVSMs) called variation co-efficient similarity measures (VCSMs) for Cq-ROFSs and IVCq-ROFSs are also proposed and their properties are discussed. Finally, in order to demonstrate the feasibility of the investigated HVSMs, the existing similarity measures about complex Pythagorean fuzzy sets (CPFSs) and complex intuitionistic fuzzy sets (CIFSs) are compared with the proposed methods by numerical examples of medical diagnosis and pattern recognition.PV/BESS to support electric vehicle charging station integration in a capacity constrained power distribution grid using MCTLBO
http://scientiairanica.sharif.edu/article_21860.html
Solar photovoltaic (PV) systems with back-up battery energy storage system (BESS) mitigate power system related issues like ever-increasing load demand, power loss, voltage deviation and need for power system up-gradation as integration of electric vehicles (EVs) increases load while charging. This paper investigates the improvements of the system parameters like voltage, power loss and loading capabilities of IEEE-69 bus radial distribution system (RDS) with PV/BESS-powered EV charging stations (CSs). The RDS is divided into different zones depending on the total no. of EVs, EV charging time and available CS service time. One CS is assigned to each zone. An energy management strategy is developed to direct the power flow among the CS, PV panel, BESS, and the utility grid according to time of use of electricity price. The BESS is allowed to sell excess energy stored to the utility grid during peak hours. Multi-course teaching learning based multi-objective optimization (MCTLBO) is used to optimize the size of PV/BESS system and the locations of CSs in each zone in order to minimize both the annual CS operating cost and the system active power loss. The results validate the use of optimal PV/BESS to power CS for techno-economic improvement of the system.Single-valued neutrosophic linguistic reducible weighted MSM for tourism mobile e-commerce service quality evaluation
http://scientiairanica.sharif.edu/article_21861.html
The tourism mobile e-commerce service quality evaluation (TMESQE) is of great concern to enterprises for enriching the service content of the enterprise and improving its market competitiveness. The key issue arises tremendous vagueness and reciprocity for TMESQE. The Maclaurin symmetric mean (MSM), as a vital information fusion tool, can capture the reciprocity among multiple given argument more effectually. Amount of weighted MSMs have been presented for dealing various neutrosophic information integration issues because the arguments are hourly interoperable. However, these kinds of weighted MSM (WMSM) operators are out of the reducibility or idempotency. To solve two above issues, we introduce the single-valued neutrosophic linguistic reducible WMSM (SVNLRWMSM) operator and the single-valued neutrosophic linguistic reducible weighted dual MSM (SVNLRWDMSM) operator. In the meantime, certain interesting properties and some special cases of developed operators are explored in detail. Whereafter, we develop two multiple attribute decision making (MADM) algorithms based on SVNLRWMSM and SVNLRWDMSM for dealing the TMESQE issue, along with the sensitivity analysis of various parameter values on final ordering. Conclusively, a comparison with some existing algorithms has been conducted for showing their availability.Maintenance policy selection considering resilience engineering by a new interval-valued fuzzy decision model under uncertain conditions
http://scientiairanica.sharif.edu/article_21862.html
Different maintenance policies, including preventive maintenance and predictive maintenance, are introduced to enhance the execution of systems. Maintenance professional experts have faced numerous challenges with distinguishing the proper maintenance policy, among which causes of failure, accessibility, and the capability of maintenance should be regarded seriously. Moreover, most organizations do not have a deliberate and compelling model for evaluating maintenance policies under uncertainty to deal with real-world conditions. The aim of this paper is to introduce a new interval-valued fuzzy (IVF) decision model for the selection of maintenance policy based on order inclination with comparability to ideal solutions by Monte Carlo simulation. This paper introduces novel separation measures and a new IVF-distinguish index via possibilistic statistical concepts (PSCs) which can assist maintenance decision makers to rank maintenance policy candidates. Also, resilience engineering (RE) factors are considered along with conventional evaluation criteria. Finally, the steps of the proposed IVF model-based PSCs are applied to survey a real case in manufacturing industry. Results of the presented model are compared with the recent literature and could help maintenance personnel in identifying the best policy systematically.A New Nonparametric Composite Exponentially Weighted Moving Average Sign Control Chart
http://scientiairanica.sharif.edu/article_21863.html
In this paper, a new nonparametric control chart based on two EWMA statistics is proposed for monitoring process deviation from the target value. The performance comparison of the proposed chart with the existing nonparametric EWMA sign control chart and a nonparametric CUSUM mean control chart are made by using out-of-control average run length. The simulation study showed the superiority of the suggested chart over the four other parametric and nonparametric charts. An empirical illustration is also provided for performance evaluation of the proposed chart. By comparing the proposed chart with the existing charts, it is concluded that the proposed chart is more sensitive in detecting a small shift in the process.Linguistic Z-number Muirhead mean operators and their applications in ethical-financial portfolio selection
http://scientiairanica.sharif.edu/article_21865.html
Traditionally the performance of firms is evaluated by financial criteria, but this study presents a new qualitative comprehensive framework that incorporates the ethical criteria into the portfolio models and it is widely matched with the preferences of socially responsible investors. The increase of corporate deceptions has caused investors or fund managers consider the ethical assessments in their investment management. Therefore, it is essential to develop models that capture the ethical criteria along with the financial criteria in the investment processes. In this study, a multi-stage methodology is proposed and linguistic Z-numbers are applied to represent the evaluation information, and the Muirhead mean (MM) aggregation operators are employed to fuse the input data under linguistic Z-number environment. Hence, we firstly develop four linguistic Z-number Muirhead mean operators. Then, using the max-score rule and the score-accuracy trade-off rule, three qualitative portfolio models are proposed. These models have been aimed to maximize the financial performance of portfolio as main objective and have been distinguished by the ethical goal that the investor follows. The obtained results of numerical example validates the capability of the models for constructing more diversified portfolio based on a trade-off between financial and ethical criteria according to investors&rsquo; preferences.Metaheuristics for a bi-objective green vendor managed inventory problem in a two-echelon supply chain network
http://scientiairanica.sharif.edu/article_21866.html
A bi-objective non-linear optimization model with the goal of maximizing the profit of inventory and minimizing the carbon emissions of transportation, simultaneously, is developed. Another contribution of this work is to propose three capable metaheuristics to solve it optimality in large-scale samples. In this regard, the Non-dominated Sorting Genetic Algorithm (NSGA-II) as a well-known method as well as Multi-Objective of Keshtel Algorithm (MOKA) and Multi-Objective of Red Deer Algorithm (MORDA) are firstly applied in this research area. The results of metaheuristics are checked by the &epsilon;-constraint method in a set of small-scale samples as compared with the results of literature. Finally, the outputs confirm that the allowed shortage situation along with the lack of cost reduction shows a greater amount of shipping and orders. As such, the performance of MORDA is approved in comparison with MOKA and NSGA-II through different criteria.Monitoring mean and variability by Gini chart for skew-normal distributed data
http://scientiairanica.sharif.edu/article_21867.html
In order to monitor mean and variability of a process, the Gini control charts based on the skew-normally distributed random samples is proposed. Through comparing the false alarm rates of current scheme with those of existing mean and dispersion control charts, it is found out that the design structure of Gini chart can improve over other classic schemes based on assumption of skew-normal distribution for the data. Moreover, the superiority of the Gini chart is studied by comparing the discriminatory power curves of the skew-normal distribution with some existing control charts. Simulated studies and a real data example illustrate the usefulness of the proposed approach.A Vehicle Routing Problem with Two Types of Ships in Container Terminals
http://scientiairanica.sharif.edu/article_21868.html
The Vehicle Routing Problem (VRP) is one of well-established and important topic in supply chain and logistic networks. The location-routing decision-making has a significant role to optimize the traveling cost per distance, total traveling time and the number of vehicles in the supply chain networks. One of recent advances in these systems refers to container terminals in the global trade centers. The new contributions of this model are to consider the routes of two types of ships (Tramp and Liner) with different properties and the time windows in order to minimize costs. The proposed is solved by an exact method (B&amp;B) as well as because of inherent complexity of problem proposed in the real-world cases, the Genetic (GA) algorithm has been used to find an optimal/global solution in a reasonable time. Finally, an in-depth analysis and discussion is provided to conclude the main findings and practical implications of the results.Stepwise pricing in evaluating revenue efficiency in Data Envelopment Analysis: A case study in power plants
http://scientiairanica.sharif.edu/article_21869.html
Data envelopment analysis (DEA) technique is widely applied for performance assessment of decision making units (DMUs). The revenue efficiency (RE) evaluation is one of the controversial subject matters that can be performed through DEA context. The amount of productions and its prices are crucial factors in the RE. The classical DEA models consider the prices to be fixed and known which are not the case in real world. Also, the classical DEA models considers linear pricing in revenue assessment. However, most of real world problems deal with nonlinear prices. This paper evaluates the RE given the piecewise linear theory in non-competitive situations. In doing so, a stepwise pricing function is introduced which lets the prices to be changed in relation to the amount of the production. As an innovative idea, a more accurate mathematical modeling for the RE is proposed. We define a dynamic weights&rsquo; function in maximum revenue optimization model which no longer considers fixed prices. A case study validates our proposed model.Determining optimal machine part replacement time using a hybrid ANN-GA model
http://scientiairanica.sharif.edu/article_21874.html
Companies must determine the replacement time of machine parts correctly since it affects their production costs and efficiencies. For this, it is aimed to determine the most appropriate replacement time to minimize cost per unit. In this study, it is proposed to develop a hybrid Artificial Neural Network (ANN)-Genetic Algorithm (GA) model to predict replacement time without using a cost model. At first, a replacement cost model is developed to calculate replacement times to use in training the neural network. Nevertheless, the cost model needs complex mathematical calculations. GA is used instead of the cost model to determine replacement time, and thus, to achieve fast learning for the neural network. The hybrid ANN-GA model was applied to predict replacement time of bladder in tire manufacturing. Furthermore, ANN and GA models, which were developed to increase the prediction accuracy of the hybrid model, were used. The hybrid ANN-GA model showed better performance with higher R^2 (0.943) and lower RMSE (9.124) and MAPE (2.528) values than the other ANN and GA models. The values indicate that the hybrid model is in good agreement with the cost model. Thus, it is recommended that the hybrid model is used instead of the cost model.Impact of Adopting Quick Response and Agility on Supply Chain Competition with Strategic Customer Behavior
http://scientiairanica.sharif.edu/article_21875.html
A growing trend towards computerization and competition in supply chains results in uncertainty and quick variability that make the decisions difficult for both levels of retailers and manufacturers. In this paper, two Bi-Level Stackelberg models are developed under non- and agile conditions in the presence of strategic customers. Our main novelty approach in this paper is to consider both levels competing with each other in a sequential game to determine the optimal production and order quantities and prices with and without agile abilities. In addition, both proposed models are simplified single-level using the Karush-Kuhn-Tucker (KKT) approach. Then, they are remodeled by the Robust Optimization technique due to existing uncertain parameters. To have a better assessment of the models&rsquo; efficiency and applicability, they have been implemented in a real case and finally, the results are compared and analyzed.Performance Measurement in the Health Care Sector: a Leader-Follower Network DEA Model based on Double Frontier Analysis
http://scientiairanica.sharif.edu/article_21876.html
Measuring the performance of laboratories as one of the most significant areas of healthcare plays a key role in the quality of laboratories management. In this paper, we consider a three-stage network comprised of a leader and two followers in respect to the additional desirable and undesirable inputs and outputs. The suggested model simulates the internal structure of a diagnostic lab (the pre-test, the test and the post-test). The criteria for evaluation are achieved by using the Fuzzy Delphi technique. Due to the social, economic and environmental impacts of health care systems, the significance of sustainability criteria is obvious in the case study indicators. We utilize the non-cooperative approach multiplicative model to measure the efficiency of the overall system and the performances of decision-making units (DMUs) from both the optimistic and pessimistic views. The non-cooperative models from these view cannot be converted into linear models. Therefore, a heuristic method is suggested to convert the nonlinear models into linear models. Finally, after obtaining the efficiencies based on the double-frontier view, the DMUs are ranked and classified into three clusters by the k-means algorithm.Sequential Nonlinear Encoding; A Low Dimensional Regression Algorithm with Application to EEG based Driving Fatigue Detection
http://scientiairanica.sharif.edu/article_21877.html
We introduce a novel Regularized Kernel Projection Pursuit Regression method which is a two-step nonlinearity encoding algorithm tailored for such very low dimensional problems as fatigue detection. This way, the data nonlinearity can be investigated from two different perspectives, first by transforming the data into a high dimensional intermediate space and then by using their spline estimations to the output variables which allows for a hierarchical unfolding of data. Experimental results on the SEED database shows an average RMSE value of 0.1080% and 0.1054% respectively for the temporal and posterior areas of the brain. Our method is also validated by conducting some experiments on Parkinson's disease prediction which further demonstrate the efficiency of our method for low-dimensional regression problems.Traditional off-the-shelf regression methods like SVR, KSVR, and GLM methods all require their link functions to be previously selected which limits their effectiveness for encoding the nonlinearity of a highly complex low dimensional data set. Moreover, conventional PPR does not deal with the very low dimensionality of data. This paper proposes a novel regression algorithm to address the encoding problem of a highly complex low dimensional data, which is usually encountered in bio-neurological prediction tasks like EEG based driving fatigue detection.Using Association Rules to Investigate Causality Patterns of Safety-Related Incidents in the Construction Industry
http://scientiairanica.sharif.edu/article_21902.html
The aim of this study is to investigate causality patterns of safety-related incidents in the construction industry. Although there are many studies to find cause-and-effect relationships in the accident database, retrieving useful knowledge from the last database and taking additional variables into account are needed. Therefore, in the present study, the association rule method was utilized to investigate a large number of historical accident data in Iran's construction industry in the duration of 2014-2017. Based on association rules results, the combination of worker's individual and behavioral factors and supervisory conditions are more related to serious accidents. These results can provide practical insights for construction managers who need to be more concerned about the negative effects of the combination of some factors on serious construction accidents.Dynamic correlation and volatility spillover between the stock markets of Shenzhen and Hong Kong
http://scientiairanica.sharif.edu/article_21903.html
Considering the two-way spillovers of market information, this paper establishes multivariate GARCH models to study the impact of Shenzhen-Hong Kong Stock Connect (SHSC) on the complex co-movements relation between the stock markets of Shenzhen and Hong Kong from the aspects of dynamic correlation and volatility spillover. On the one hand, a t-Copula DCC-GARCH model which combines the Copula function with the DCC-GARCH model is established to model the return rate series of stock index in different stages, and the characteristic that the dynamic correlation coefficient changes with time is analyzed emphatically. On the other hand, a BEKK-GARCH model is established to measure the changes of the volatility spillover effect between the stock markets in Shenzhen and Hong Kong. The results show that the opening of SHSC has gradually increased the dynamic correlation coefficient of the two stock markets, and the openness degree of the two stock markets has increased. At the same time, the volatility spillovers of stock markets in Shenzhen and Hong Kong have shifted from one-way spillover to two-way spillovers, which indicates that the SHSC mechanism has strengthened the correlation degree and has improved the ability of risk spillover in the two stock markets.Reliability Evaluation of Power Systems Containing Ocean Thermal Energy Conversion Power Plants
http://scientiairanica.sharif.edu/article_21904.html
Ocean thermal energy conversion system uses from water in surface of the ocean as high temperature source and water in the depth of the ocean as low temperature source. Three types of ocean thermal energy conversion systems including close cycle, open cycle and hybrid systems are available. In a close cycle system, working fluid through a thermodynamic cycle based on the Rankine cycle can rotate the turbine and generate electricity. Due to the variation in the ocean surface temperature, the output power of the ocean thermal energy conversion system is not fixed and controllable and so this uncertainty nature results in the numerous states in the generated power of this plant. Thus, in integrating ocean thermal energy conversion systems to the power system, many aspects of power system such as reliability may be affected and so new approaches must be developed for investigation these effects. In this regard, in this paper for the first time, the reliability of power system containing ocean thermal energy conversion system is evaluated and the valuable indices such as loss of load expectation, expected energy not supplied and peak load carrying capability that can be used for generation expansion planning of power system, are calculated.Monitoring Attributed Social Networks Based on Count Data and Random Effects
http://scientiairanica.sharif.edu/article_21912.html
This paper presents a novel approach for the statistical monitoring of online social networks where the edges represent the count of communications between ties at each time stamp. Since the available methods in the literature are limited to the assumption that the set of all interacting individuals is fixed during the monitoring horizon and their corresponding attributes do not change over time, the proposed method tackles these limitations due to the properties of the random effects concepts. Applying appropriate parameters estimation technique involved in a likelihood ratio testing (LRT) approach considering two different statistics, the longitudinal network data are monitored. The performance of the proposed method is verified using numerical examples including simulation studies as well as an illustrative example.A New Approach for the Setting of Directional Overcurrent Relays by Incorporating Cascading Outages
http://scientiairanica.sharif.edu/article_21914.html
Directional overcurrent relays (DOCRs) are the essential protective devices in distribution networks which are usually set without considering any contingencies. However, the current challenge in power systems is the existence of uncertainty and its unfavorable consequences. It sometimes appears that some elements simultaneously fail which makes other parts to be overloaded to the extent that it leads to cascading outages. Therefore, DOCRs may have mal-operation which ends in unwanted trips when there is no fault, or they may not operate in the case the fault is located within their reach point. In such cases, the coordination setting will need complex programming with many related non-linear inequality constraints. In this paper, a novel hybrid method is proposed based on multi-objective optimization including new objective functions by using the genetic algorithm (GA). Also, the cascading outages are considered in the presented method based on network data analysis. This approach is performed on distribution part of the IEEE 14-bus meshed system, and a real industrial radial feeder named TOSEE, located in Iran. The simulations have been implemented in MATLAB and PowerFactory-DIgSILENT software packages in different models, and the results are evaluated.Efficiency assessment of medical diagnostic laboratories using undesirable sustainability indicators: A network data envelopment analysis approach
http://scientiairanica.sharif.edu/article_21927.html
Assessing the performance of health systems assists health decision-makers to ensure the accountability for their decisions. Medical diagnostic laboratories are one of the most important and sectors in the healthcare system of all countries. Thus, an assessment of the performance of medical diagnostic laboratories is of particular importance. This paper aims to propose a network data envelopment analysis (NDEA) model to assess the performance of medical diagnostic laboratories and decomposing the efficiency of the system with intricate internal structure based on sustainable development indicators. In addition, the proposed model is designed according to the internal structure of the medical diagnostic laboratory, which includes three main laboratory processes (the pre-test, the test and the post-test) with a combination of additional inputs and outputs (including both desirable and undesirable). The proposed model is a multiplicative DEA approach to estimate and decompose the efficiencies of system. Thus, a heuristic method is used as a suitable solution to convert a multiplicative NDEA approach into an equivalent linear program. The performance proposed model is shown through a real study in Iran. The computational results demonstrate the applicability of the proposed model in determining the most efficient laboratory using undesirable sustainability indicators.An application of energy efficiency programs on multi-stage transmission network expansion and reactive power planning
http://scientiairanica.sharif.edu/article_21928.html
Energy efficiency programs as an energy source with multiple advantages (low cost, more reliable and better clean) are considered as one of the most effective solutions to meet future energy needs. In this paper, energy efficiency programs are modelled as virtual sources of power generation to investigate their impacts on expanding transmission network and reactive power planning. A multi-stage model based on AC power flow has been used to indicate the possibility of postponing the investment actions as the investment deferral in transmission expansion problems. Two groups of regulatory support schemes are considered as investor income to promote participation in energy efficiency programs, namely purchasing certified emission reductions and shared saving model. In addition, two standard case studies (Garver &amp; 46-bus Brazilian) are evaluated to demonstrate the promising potential of the proposed model in handling the planning problems of practical power systems. The simulation results show the effectiveness of the proposed model to solve such planning problems in the presence of energy efficiency programs.Fuzzy Mathematical Models for Maximizing Contractors’ and Clients’ Satisfaction by Considering Flexible Start Date of the Project
http://scientiairanica.sharif.edu/article_21931.html
Resource-Constrained Multi-Project Scheduling Problem (RCMPSP) is considered a significant topic in project management studies and many kinds of research have been carried out in this field which have been proposed numerous approaches. However, in most of them, the viewpoints of clients and contractors, two important stakeholders of the project are not directly considered. The current research tries to introduce a new approach of RCMPSP in order to schedule the project portfolio and allocate the budget as a limited resource simultaneously. In this way, first, the client's and contractors' budget satisfaction is defined. Then some budget allocation models have been proposed to maximize the clients' and the contractors&rsquo; satisfaction. These models consider constraints such as the minimum cost required for each project, the maximum budget for each period, and the flexibility for the start date of each project. To illustrate the proposed models, a real case of the project portfolio is considered.Analytical Study, Design and Optimization of Radial-Flux PM Limited-Angle Torque Motors
http://scientiairanica.sharif.edu/article_21933.html
This paper presents an analytical study of the radial-flux slotless limited-angle torque motors. The modelling is based on the magnetic equivalent circuit of the actuators and uses the electromagnetic equations to calculate the air-gap flux as well as the produced torque. This model is then used for designing the actuators both in outer-rotor and inner-rotor structures, considering the design constraints and desired characteristics. As the objectives in design stage usually conflict with each other, an intelligent multi-objective optimization algorithm is required to design the best fit actuators. Analytical and simulation results are presented and compared to show the accuracy of the model and verify the design equations as well as the design approach. As this type of actuators is a key element in industrial control, the contributions of this paper are focused on new analytical field solution based on magnetic equivalent circuit, design and optimization approach for radial-flux structure and introducing a general procedure that could be extended to similar structures and actuators.The Comparative Analysis of AC-Flux and DC-Flux Resolvers
http://scientiairanica.sharif.edu/article_21935.html
Resolver, as an electromagnetic sensor, is widely used in many industrial applications. It can detect the position of the rotary part of the electric machines precisely. In commercial resolvers, the excitation winding is connected to the high frequency (HF) AC source. The amplitude-modulated voltages induced in the signal windings need to be demodulated in order to calculate the envelope of the output signals and accordingly detect the position. On the other hand, in PM-resolver, signal windings replaced by Hall-effect sensors to measure the DC magnetic flux which is produced by permanent magnets. In this study, the performance of both AC and DC flux resolvers is investigated under different circumstances. All the simulations are done by the time-stepping finite element method (TSFEM).A novel risk assessment approach using Monte Carlo simulation based on co-occurrence of risk factors: A case study of a petrochemical plant construction
http://scientiairanica.sharif.edu/article_21936.html
Nowadays, because of the advancement of technology and subsequently unpredictable events, it is important for addressing risk management as an important part of projects and business. In this paper, a novel approach based on Monte Carlo simulation has been proposed for risk assessment, which considers the co-occurrence of risks. In this method, the output of extended and classic Monte Carlo simulation is applied for co-occurrence-based risk assessment (CORA) and prioritization. Also, the magnitude in each source of uncertainty has been determined by a new approach. The proposed model investigates risk&rsquo;s relationship and determines the type of effect as resonance or reduction in addition to identifying and analyzing the risks. Also, a system dynamic model is applied to illustrate the relationships of risks. Finally, this method is applied to a petrochemical project. Five risks as temperature, rain, labor, cost, and inflation are considered in this project. Based on the numerical results, the most important risk is inflation. Also, there is a significant different between the result of the proposed model in comparison with model that ignore the co-occurrence of risks. CORA helps the manager to consider all aspect of risks and help them to have a better decision.Calculation of Urban Transportation Network Reliability Considering Correlation Among the Links Comprising a Route
http://scientiairanica.sharif.edu/article_21940.html
Recently, the researchers in the field of urban transportation network planning have become increasingly interested in network reliability, publishing research works focused on the calculation of various types of network reliability. Accurate calculation of network reliability has led the transportation network optimizers toward new approaches . Travel time reliability is among the most important reliabilities investigated when analyzing urban transportation networks, with various approaches based on different assumptions proposed for calculating it. In the present research, the uncertainty associated with the demand for travel and the flows passing across links and also the correlations among the links comprising a route were considered to calculate the travel time for each of the network links. Moreover, it was shown that this process follows shifted log-normal distribution. These calculations are expected to serve as a basis for the employment of travel time reliability of a network within the modeling of an urban transportation system, so as to increase the accuracy and reliability of the simulations. Finally, in order to validate the model, an urban network with 12 nodes, 21 links, and 4 origin-destination pairs was subjected to the travel time reliability assessment by calculating the travel time over all forming links.An Optimization Model for Scheduling Freight Trains on a Single Rail Track
http://scientiairanica.sharif.edu/article_21951.html
In many countries, a rail network consists of a series of single lines with sidings where inter-train interactions (meeting, passing) occur. An effort has been made in this paper to study two of these network-related issues: 1) scheduling freight trains in a single-line corridor while ensuring the interactions to happen safely and 2) allocating freight to the scheduled trains considering the freight due/release date and train&rsquo;s weight/capacity. To better illustrate the real-world freight trains&rsquo; scheduling problems, both the scheduling and allocation problems have been addressed. Minimizing the trains&rsquo; traveling time, allocating maximum freight to the scheduled ones, and minimizing the total freight tardiness at the related destination are the objective functions of this study. Both problems and their solutions have been addressed separately using integer linear programming models, but an integrated novel heuristic algorithm has been proposed to solve them. The computational results demonstrated through a generated data set show both the model validation and the efficiency of the heuristic algorithm. This heuristic algorithm has been so designed to incorporate the practical operational railway rules with modest modification and although its outputs slightly differ from the exact solutions, it can solve both models simultaneously in large scale problems.Control Parameter Based Comparative Study of Radiation Properties of TMCCAA and TMHSCAA
http://scientiairanica.sharif.edu/article_21952.html
Two different configurations have been considered for the optimal design of radiated electric field pattern characteristics of antenna arrays. Time-modulated concentric circular antenna array (TMCCAA) and time-modulated half symmetric circular antenna array (TMHSCAA) have been dealt with for the comparative analysis of control parameters of the radiation properties of the antenna array. Collective animal behaviour (CAB), an evolutionary approach, is applied as the optimisation tool. The effect of different control parameters of the radiation pattern of TMCCAA is compared by taking two different cases. In the first case, i.e., Case-1, only one parameter (switching time sequence) is used as the control parameter for the optimisation of the radiated electric field pattern of TMCCAA. In the second case, i.e., for Case-2, three control parameters, switching ON-OFF time of each ring, inter-element spacing, and ring radii are optimised. In the second array, the effect of different control parameters of the radiation pattern of Time-Modulated Half Symmetric Circular Antenna Array (TMHSCAA) is compared by taking two different cases. Simulation results obtained for 20- elements TMHSCAA with uniform amplitude and spacing are analysed. Optimized SLL values obtained for the Case-1 and Case-2 of TMCCAA are -24.68 dB and -46.15 dB, respectively.An Optimal Two-level Supply Chain Model for Small and Medium-sized Enterprises with a rework for New Products and Price-Dependent Demand
http://scientiairanica.sharif.edu/article_21954.html
The advent of new technologies, globalization of markets, customers' varied needs, and increasingly fierce competition, is making SMEs seek to improve engagement with their suppliers and cost management practices in order to survive. Thus, SMEs clearly need to focus on the interests of the entire supply chain by enacting win-win policies. In this study, we investigate a two-level inventory model featuring a manufacturer and a buyer in the competitive market with the policy of producing new products. Imperfect quality products and the capacity to rework are also considered in the model. In other words, because of the competitive nature of the market, any increase in price leads to a decrease in demand. The mathematical model is proposed over two scenarios: a scenario where shortage can occur, and one with no possibility of shortage. The objective function of the mathematical model revolves around the central goal of maximizing the total profit of the supply chain considering both independent and joint optimization by the supply chain members. A new algorithm is proposed to solve the mathematical model whose applicability is evaluated by giving a numerical example to the analysis software MATLAB. The final results are analyzed and discussed using sensitivity analysis approach.Designing a risk-adjusted CUSUM control chart based on DEA and NSGA-II approaches (a case study in healthcare: Cardiovascular patients)
http://scientiairanica.sharif.edu/article_21982.html
Researchers have recently devoted a lot of attention to the development of control charts for monitoring healthcare systems. Accordingly, the purpose of this paper is to design a risk-adjusted cumulative sum (CUSUM) control chart to detect decreasing shifts. The proposed chart is used to monitor the survival times of patients who may be subject to an assignable cause such as human mistakes during a surgery. To this end, risk adjustment is performed to consider the impact of each patient's preoperative risks on survival times using survival analysis regression models. However, using the risk-adjusted CUSUM requires that the control chart parameters are determined. Hence, a multi-objective economic-statistical model is proposed and a two-stage solution method including non-dominated sorting genetic algorithm (NSGA-II) and Data Envelopment Analysis (DEA) is implemented to solve the model and obtain the optimal design parameters. The performance of the proposed approach is also studied in a real cardiac surgery center. Finally, to confirm the effectiveness of the proposed multi-objective design, two comparisons with the bi-objective and pure economic designs are made. The results show that the performance of the risk-adjusted CUSUM obtained from the proposed model is better than the two other designs considering statistical and economic properties.A hybrid metaheuristic algorithm for a data driven leagile sustainable closed-loop supply chain model under disruption risks
http://scientiairanica.sharif.edu/article_21988.html
In the current situation,taking into consideration the environmental and social issues are related with the production and distribution of products in supplychain systems,due tothe global concerns related with emitting lots of greenhouse gaseswithin the manufacturing process and overlooking the major needs of publicThis paper proposes a newmultiobjectivemodel in the area ofclosed loop supplychainproblem integrated with lot sizing by considering lean,agility and sustainability factors simultaneously.In this regard,responsiveness, environmental,social and economic aspects are regarded in the model besides the capacity and service level constraints.Inaddition,strategic and operational backup decisions are developed to increase the resiliency of the system against disruption of the facilities and routs simultaneously.Next,a robust possibilistic programming approach is applied to handle the uncertainty of the model.To increase the responsiveness of the system,a fuzzyc-means clusteringmethod isapplied to select the potential locations based on the proximity to local customers.In the following, a new hybrid metaheuristic algorithm comprised of a PMOPSO algorithm and aMOSEO is developed to deal with large size problems efficiency and to assess the impact of using a single-based initial solution as the income for the second phase of the proposed hybrid algorithm.To ensure about the effectiveness of the proposed hybrid algorithm,the results of this algorithm arecompared with a NSGA-II.Chance constrained programming and robust optimization approaches for uncertain hub location problem in a cooperative competitive environment
http://scientiairanica.sharif.edu/article_21989.html
In this paper, we propose an integer programming model for Capacitated Multi-Allocation Median Hub Location Problem, which is applied in a both cooperative and competitive environment among airlines. We divide the hubs into six independent categories by comparing the parameters of the ticket price, travel time, and the service quality of hub airports are controlled by follower and leader airlines. In this paper, the degree of importance of time and cost parameters determine by a multivariate Lagrange interpolation method, which can play an important role in allocating travelers to follower airline hubs. Then, based on the seasonal demand of travelers, we consider travel demand as uncertain parameters. To determine the deterministic equivalent forms of this category of hub location models, robust optimization method and chance-constrained programming model are used. Finally, the proposed model test in a case study. Based on the results, a coalition of follower airlines can absorb nearly 2% of travelers of leader airline due to lower travel cost and travel time compared to that of leader airline.Monitoring Process Mean Using a Second Order Filter: Signal and System Approach
http://scientiairanica.sharif.edu/article_21990.html
In statistical process control one objective is to control the stability of a process. A process is stable when its mean is in control and variance bounded. Different control charts were introduced for monitoring the mean and variance of a process by plotting suitable test statistics on the chart. In this research design of a system which converts the sample mean to a test statistics was proposed. The second order filter, a special class of the Linear Time Invariant (LTI) systems, was used to design the converting system. It was shown that design of a low pass filter was better for detecting a level (mean) change in the process. Markov chain approach was also followed to construct appropriate control chart and to estimate its control limits. Simulated data under normality assumption for different scenarios were used to compare the proposed control chart with Shewhart and Exponentially Weighted Moving Average charts by means of ARL and PFS criteria. Existing data from the Central Bank of Iran was also applied to evaluate the suggested method. The signal to noise ratio was used to assess the performance of this method at different stages. Results indicate that the proposed method detects shifts more rapidly.Self-efficiency Assessment of Sustainable Dynamic Network Healthcare Service System under Uncertainty: Hybrid Fuzzy DEA-MCDM method
http://scientiairanica.sharif.edu/article_21992.html
In this paper, sustainability-related factors driving success of healthcare system management include a group of hospitals are considered. A three-pronged approach is considered based on the internal functions of the hospital, which are affecting the social responsibility as well as functions related to the service recipients from health centers. A novel comprehensive multi-period evaluation of hospitals&rsquo; performance is considered by the proposed dynamic network. This hybrid data envelopment analysis-based fuzzy multi-criteria decision-making model incorporates fuzzy DEMATEL and best-worst method provides several useful managerial insights using a realistic case study from Iran for sustainable management of the healthcare system. Obtained results indicate the importance of considering potential inter-related relations between network nodes on comprehensive performance assessment of healthcare service system.Efficiency Measurement for Hierarchical Network Systems Using Network DEA and Intuitionistic Fuzzy ANP
http://scientiairanica.sharif.edu/article_21993.html
According to the high importance of the university in the growth and development of the country, the evaluation performance of educational and research groups in universities is very important. The black-box Data Envelopment Analysis (DEA) model is mathematical programming for measuring the relative efficiency of a set of DMUs, without considering the operations of the component processes that may have misleading results. To overcome this defect, network models are recommended. This paper intends to propose a hybrid Intuitionistic Fuzzy Analysis Network Process (IFANP) and Network DEA (NDEA) technique to evaluate the efficiency of the faculty of basic sciences of Islamic Azad University. The IFANP method is used to evaluate the overall weights among all the criteria and sub-criteria and these weights are used in the NDEA model to measure the relative efficiency of a system. The hypothetical example shows that the efficiency of all DMUs is equal to 1 by using the DEA, and there is no ranking between DMUs. The results of the IFANP-NDEA are more meaningful because of the full ranking of DMUs, considering component process operations. Also, it can prioritize efficient DMUs, provide the efficiencies of the DMU&rsquo;s functions which enables managers to identify areas of weakness.Green closed-loop supply chain network design with stochastic demand: a new accelerated benders decomposition method
http://scientiairanica.sharif.edu/article_21997.html
Changing the structure of supply chains to move towards less polluting industries and better performance has attracted many researchers in recent studies. Design of such networks is a process associated with uncertainties and control of the uncertainties during decision-making is of particular importance. In this paper, a two-stage stochastic programming model was presented for the design of a green closed-loop supply chain network. In order to reach the environmental goals, an upper bound of emission capability that helps governments and industries to control greenhouse gas emissions was considered. During the reverse logistics of this supply chain, waste materials are returned to the forward flow by the disassembly centers. To control the uncertainty of strategic decisions, demand and the upper bound of emission capacity with three possible scenarios is considered. To solve the model, a new accelerated Benders decomposition algorithm along with Pareto-Optimal-Cut was used. The efficiency of the proposed algorithm was compared with the regular Benders algorithm. The effect of different numerical values of parameters and probabilities of scenarios on the total cost was also examined.A new improved class of ratio-product type exponential estimators of the population variance
http://scientiairanica.sharif.edu/article_21998.html
Several auxiliary information-based estimators of the population variance are available in the existing literature of survey sampling. Mostly, these estimators are based on conventional dispersion measures of the auxiliary variable. In this study, a generalized class of ratio-product type exponential estimators of the population variance is proposed which integrates the auxiliary information on non-conventional dispersion measures under simple random sampling in the ratio-type exponential class of estimators. The performance of the proposed estimators is compared, theoretically and numerically, with the several existing estimators of the population variance. It is established that the proposed class of estimators outperforms the existing estimators in terms of the lower mean square and relative root mean square errors. Moreover, the percentage relative efficiency of the proposed estimators is much higher as compared to their counterparts.The adjustable approaches to multi-criteria group decision making based on inverse fuzzy soft matrices
http://scientiairanica.sharif.edu/article_21999.html
In this paper, we focus on the matrices representing the inverse fuzzy soft sets over both the universal object set and the universal parameter set. Some basic operations and properties of these inverse fuzzy soft matrices are investigated. Moreover, two adjustable approaches to multi-criteria group decision making (MCGDM), namely inverse fuzzy soft sum-product decision making (IFSSPDM) and inverse fuzzy soft distributive If-difference decision making (IFSDIf-dDM), are proposed. The IFSSPDM approach achieves the optimal choice for the MCGDM problem based on the inverse fuzzy soft structures consisting of multiple-discrete parameter sets and common universal object sets. The objective of IFSDIf-dDM approach is to present a solution for the MCGDM problem based on the inverse fuzzy soft structures consisting of a common universal parameter set and two discrete universal object sets. Thus, the solutions can be obtained using the practicality of inverse fuzzy soft matrices for two different types of decision making problems. Besides, the comparisons are presented showing that the proposed approaches produce more convincing outputs than the current fuzzy soft approaches.Quantile regression-ratio-type estimators for mean estimation under complete and partial auxiliary information
http://scientiairanica.sharif.edu/article_22000.html
Traditional ordinary least square (OLS) regression is commonly utilized to develop regressionratio-type estimators with traditional measures of location. Abid et al. (2016b) extended this idea and developed regression-ratio-type estimators with traditional and non-traditional measures of location. In this article, the quantile regression with traditional and non-traditional measures of location is utilized and a class of ratio type mean estimators are proposed. The theoretical mean square error (MSE) expressions are also derived. The work is also extended for two phase sampling (partial information). The pertinence of the proposed and existing group of estimators is shown by considering real data collections originating from different sources. The discoveries are empowering and prevalent execution of the proposed group of estimators is witnessed and documented throughout the article.A multi-objective vibration damping optimization algorithm for solving a cellular manufacturing system with manpower and tool allocation
http://scientiairanica.sharif.edu/article_22002.html
In this paper,a novel bi-objectivemathematical model is proposed to designa four-dimensional (i.e.,part, machine, operator, and tool) cellular manufacturing system (CMS) in a dynamic environment. The main objectives of this model are to 1) minimize total costs including tools processing cost, costs of transporting cells between various cells, machine setup cost, and operators&rsquo; educational costs, and 2) maximizing skill level of operators. The developedmodel is strictly NP-hard and exact algorithms cannot find globally optimal solutions in reasonably computational time. So, a multi-objective vibration damping optimization algorithm (MOVDO) with a new solution structure that satisfies all the constraints and generates feasible solutions is proposed to find near-optimal solutions in reasonablycomputational time. Since there is no benchmark available inthe literature, three other meta-heuristic algorithms (i.e., non-dominated sorting genetic algorithm (NSGA-II), multi-objective particle swarm optimization (MOPSO) and multi-objective invasive weeds optimization (MOIWO)) with the similar solution structure are developed to validate theperformance of the proposedMOVDOalgorithm for solving various instances of the developed model. A Taguchi method is employed to calibrate the main parameters ofthese fouralgorithms. The result of comparing theirperformances based on statistical tests and different measuring metrics reveals that theproposed MOVDO algorithm outperforms remarkably better than other meta-heuristics used in this paper.Multistage supply chain production–inventory model with collaborative preservation technology investment
http://scientiairanica.sharif.edu/article_22004.html
This paper investigates a multistage production&ndash;inventory model for deteriorating items, including raw materials and finished goods, based on collaborative preservation technology investment, hitherto not treated in the previous researches. The major purpose is to determine the optimal materials supply, production delivery, replenishment and investment policies for maximizing the joint total profit of the integrated system. Considering the proposed model, this paper uses mathematical programming analysis to ascertain the optimal solutions. Furthermore, several numerical examples are presented to demonstrate the solution process and verify the concavity of the proposed model. Sensitivity analyses with respect to major parameters are also performed. The numerical results shows that market demand, fixed shipping cost, production rate, manufacturer&rsquo;s sales price and holding cost of finished goods may affect the optimal number of shipments. Besides, when collaborative preservation technology investment becomes an option, whether the effect of the deterioration rate of raw materials or finished goods on the shipping and ordering quantity will be reduced by preservation technology investment. Finally, the increase in the amount of raw materials used to produce a finished product implies the amount of finished goods produced by the original material quantity is reduced, so the preservation technology investment will be increased.Multi-objective robust mathematical modeling for emergency relief in disaster under uncertainty
http://scientiairanica.sharif.edu/article_22014.html
This paper presents a robust location-allocation planning problem for emergency relief in a disaster situation, which is formulated as a robust optimization model. It is a multi-objective, multi-commodity, multi-vehicle and multi-level logistics model considering injury variety through service prioritizing for more injuries and considering unmet demand of particular item type in various damaged areas, public donation of different relief goods, using capacitated medical centers and emergency centers regarding damage type and capacitated relief distribution centers and disaster management centers. This a non-linear mixed-integer programming model that simultaneously optimizes three objectives; i.e., maximizing service fairness to damaged areas, maximizing fair commodity disaster management, and minimizing the total logistics cost. To solve such a hard problem, an NSGA-II is developed and the Taguchi method is applied to adjust its parameters. The &epsilon;-constraint method is used for the evaluation of the proposed algorithm performance. Three comparison metrics, including diversification, spacing and mean ideal distance, are used. The results verify the algorithm&rsquo;s effectiveness in a reasonable computational time. Eventually, to examine the applicability of the presented model and the proposed algorithm, a case study is analyzed in the area located in the north of Iran, known with historical earthquake records and aggregated active faults.Developing Mixed EWMA-CUSUM and CUSUM-EWMA control charts based on MRSS and DRSS procedures
http://scientiairanica.sharif.edu/article_22019.html
The mixed EWMA-CUSUM and CUSUM-EWMA control charts are among the control charts provided in recent years by combining two exponentially weighted moving average and cumulative sum charts for efficient monitoring of the process mean. In this paper, we extended these mixed control charts by using new median ranked set sampling and double ranked set sampling procedures. The performance of the proposed mixed control charts is evaluated through extensive Monte Carlo simulations in terms of average run length criterion and the results show the proposed charts outperform the similar charts for detecting different shifts in process mean. Furthermore, a real data-set is also presented for explaining the implementation of the proposed control charts.Transient Solution of Multiple Vacation Queue with Discouragement and Feedback
http://scientiairanica.sharif.edu/article_22021.html
The congestion problems with processor vacations have confronted with increasing intricacy, and their explicit transient solutions are exceptionally hard to compute. The transient solution is more significant for studying the dynamical behavior of computing systems over a finite period and predominantly utilizes within the state-of-the-art design architect for a real-time I/O system. Motivated from this, we adopt the mathematical concepts, namely continued fractions and generating function, to derive explicit expressions for transient-state probabilities. Transient-state probabilities of the processing delay problem with a single processor which adopts the multiple vacations policy to save power consumption and thermal trip error with discouragement and feedback are obtained in terms of modified Bessel functions using the properties of the confluent hypergeometric function. Due to the inaccessibility of processor, discouragement behaviors balking and reneging of the job requests are prone to exhibit. Routing back for the service feedback for the processed job request is also critical to maintaining the quality of service $(QoS)$. For the glance of the I/O system performance, the expected value of the state of the computing system using stationary queue-size distribution is also derived.Optimisation of Two-sided Assembly Line Balancing with Resource Constraints Using Modified Particle Swarm Optimisation
http://scientiairanica.sharif.edu/article_22042.html
Two-sided Assembly Line Balancing (2S-ALB) is important in assembly plants that produce large-sized high-volume products, such as in automotive production. The 2S-ALB problem involves different assembly resources such as worker skills, tools, and machines required for the assembly. This research modelled and optimised the 2S-ALB with resource constraints. In the end, besides having good workload balance, the number of resources can also be optimised. For optimisation purpose, Particle Swarm Optimisation was modified to reduce the dependencies on a single best solution. This was conducted by replacing the best solution with top three solutions in the reproduction process. Computational experiment result using 12 benchmark test problems indicated that the 2S-ALB with resource constraints model was able to reduce the number of resources in an assembly line. Furthermore, the proposed modified Particle Swarm Optimisation (MPSO) was capable of searching for minimum solutions in 11 out of 12 test problems. The good performance of MPSO was attributed to its ability to maintain the particle diversity over the iteration. The proposed 2S-ALB model and MPSO algorithm were later validated using industrial case study. This research has a twofold contribution; novel 2S-ALB with resource constraints model and also modified PSO algorithm with enhanced performance.A Dual Model for Selecting Technology and Technology Transfer Method Using a Combination of the Best-Worst Method (BWM) and Goal Programing
http://scientiairanica.sharif.edu/article_22043.html
Supplier selection is vital in the supply chain, with significant effects on the chain structure. Three important factors contribute to this process, namely, product/technology selection, selection of the technology/product transfer method, and supplier selection. In this study, after defining the influential criteria for these factors, the best-worst method (BWM) was employed for measuring the weights. Next, the three factors were incorporated into goal programming (GP) to minimize the cost and failure and maximize the level of service and environmental compliance. The results of the GP indicated the level of demand allocation to the supplier(s). Overall, the gray analytical network process (GANP) is used as the best decision-making method, and over the past four years, BWM has been applied in decision-making processes. Therefore, the GANP method was used to measure the weights of criteria. These weights were also incorporated into GP for comparison with the proposed combination. The results showed the superiority of BWM-GP over GANP-GP, given the reduced cost and failure, besides the increased level of service and environmental compliance.Control of Doubly-fed Induction Generator with Extended State Observer under Unbalanced Grid Conditions
http://scientiairanica.sharif.edu/article_22045.html
Under unbalanced grid condition, in a doubly-fed induction generator (DFIG), voltage, current, and flux of the stator become asymmetric. Therefore, active-reactive power and torque will be oscillating. In DFIG controlling rotor side converter (RSC) aims to eliminate power and torque oscillations. However, simultaneous elimination of the power and torque oscillations is not possible. Also, grid side converter (GSC) aims to regulate DC-Link voltage. In this paper, in order to regulate DC-Link voltage, an extended state observer (ESO) based on a generalized proportional-integral (GPI) controller, is employed. In this controlling method, DC-Link voltage is controlled without measuring the GSC current, and due to using the GPI controller, the improved dynamic response is resistant against voltage changes, and the settling time is reduced. A versatile rotor position computation algorithm (RPCA) is utilized to measure the rotor speed. This algorithm is simple, yet it is accurate and is resistant to changes in the resistance of the rotor and stator. The simulations are implemented by MATLAB software in the synchronous positive and negative sequence reference (d-q).A fuzzy chance-constrained programming model for integrated planning of the wheat supply chain considering wheat quality and sleep period: a case study
http://scientiairanica.sharif.edu/article_22046.html
Wheat is a staple food in many countries, and as a result, the first most cultivated crop worldwide. Since wheat is a vital product in terms of food security, and its supply chain needs to be studied and planned carefully. This paper proposes a mixed-integer linear programming model for integrated planning of imported and domestically-produced wheat that addresses supplier selection, order planning, transportation, storage, and distribution problems at the same time. Specifically, this model focuses on the wheat quality and wheat sleep period. Moreover, differentiation of long-term and short-term storage facilities and consideration of intra-layer flows between storage facilities are other characteristics of this model. A fuzzy chance-constrained programming approach is employed to cope with the uncertainties associated with domestic supply, demand, and global wheat prices. Applicability and advantages of the developed model are demonstrated using real data from the wheat supply chain of Iran. Results show that the current status of the wheat supply chain of Iran is far from being optimal, and there are many opportunities for improvement.Imperfect and variable production cost in three-layer supply chain system incorporating deterioration and screening effect
http://scientiairanica.sharif.edu/article_22047.html
This paper develops a three-layer supply chain for defective and non-defective types of produced items by supplier and manufacturer. The condition of the chain that without any financial liability on the manufacturer, defective items will be sent back to the supplier after screening. In the subsequent stage, the retailer accepts the non-defective items produced by the manufacturer after the screening and sends back the defective items to the manufacturer. Hence the retailer receives the perfect quality items for selling to the customers, but the retailer considers the effect of the deterioration of items. This model also considers the impact of several business strategies such as; optimal order size of raw materials, production rate, unit production cost, idle time costs of the supplier, and manufacturer in a collaborative marketing system, etc. to determine the optimum average profit of the integrated model. This study discusses the selling price of the retailer, demand rate of the customer, purchase cost of supplier and holding cost, which can be a significant breakthrough in expanding the profit of the business in real terms. Numerical example and sensitivity analysis are presented to illustrate the phenomenon of theoretical study and demonstrate the managerial implication of the model.Enhancement of Power Quality Utilizing Photovoltaic fed D-STATCOM Based on Zig-Zag Transformer and Fuzzy Controller
http://scientiairanica.sharif.edu/article_22048.html
Distribution Static Synchronous Compensator (D-STATCOM) is a shunt compensator in the distribution systems that one of the most important tasks is to improve the imbalance, reduce and eliminate the nonlinear loads harmonics. Distributed generation resources such as photovoltaic (PV) array can be used as the DC input of D-STATCOM. In this paper, PV array and DC/DC boost convertor are used to stabilize the DC link voltage of D-STATCOM. The main advantage of the proposed method is that for all time provides continuous compensation. Another power quality issues are neutral current in four-wire systems that are created due to the harmonics and system imbalance. Zig-Zag transformer is one of the ways for compensating neutral current and providing isolation between the convertor and flow of the fundamental zero sequence component which contains harmonic neutral current. Role and performance of the distribution shunt compensator in the improvement of power quality indices depends on the performance of its control system. In this paper, the control scheme of synchronous reference frame theory based on fuzzy controller is used for D-STATCOM based on PV and Zig-Zag transformer. Performance and behaviour of the proposed system examined using Matlab/Simulink software and the results will be presented.The equilibrium of venture capital incentive contract: Optimization and Q-learning approaches
http://scientiairanica.sharif.edu/article_22049.html
This paper presents an incentive contract model for allocating the income of venture projects. Venture Capital (VC), as one of the main sources of financing innovative projects, faces challenges like moral hazards, information asymmetry and interest conflicts (three agency problems). In addition to identifying the items that may affect the income of venture projects and the introduction of cost functions, we present an optimal incentive contract model from the perspective of both venture capitalists and entrepreneurs. In this model, a venture capitalist, as an active investor, provides managerial and training assistance to the entrepreneur. The results showed that the higher the initial ability of the entrepreneur, the less money the venture capitalist pays for training. Furthermore, the wealth that the contract parties can obtain if the venture contract is not accepted, is an influential factor in the contract payment function. This model has also been studied with bounded rationality hypothesis and has been implemented using the Q-learning algorithm. In addition, the results obtained from the Q-learning approach, are reasonably convergent with the Nash equilibrium.Smart Microgrid Educational Laboratory: An Integrated Electric and Communications Infrastructures Platform
http://scientiairanica.sharif.edu/article_22050.html
Microgrids as the local area power systems are changing the power system landscape due to their potential of offering a viable solution for integrating renewable energy resources into the main grid. From the operational point of view, microgrids should have the appropriate power electronic interfaces, control schemes, as well as monitoring and automation infrastructures to provide the required flexibility and meet the related IEEE 1547 standard requirements. This paper describes some of the efforts made in the smart microgrid educational laboratory to provide these facilities and create a real-world conditions needed to conduct researches and teach the related courses. Laboratory works not only increase the practical skills of the students but also can motivate them to pursue theoretical courses with more passion. The introduced facilities are somehow unique for the integration of both electric and communication infrastructures which overcome the shortcomings of not considering data transfer challenges in the studies. Complete hardware design of power plant components, and incorporation of solar photovoltaic (PV) and two types of wind turbine generations are some of the efforts made to bring the real-world conditions in the laboratory. In the load-related side, dynamic behaviors of the various types of motors are modeled.Presenting the mathematical model to optimize the reliability of the satellite attitude determination and control system
http://scientiairanica.sharif.edu/article_22051.html
The key issue in this study has been the integration of redundancy allocation and optimization of failure rates. The fact that we only need to work with parallel allocation and increase the number of components in a subsystem in parallel to improve the reliability or availability of parallel-series systems is necessary, but not enough. It is worth mentioning that in this research, the improvement of failure rates of different components in the system has been studied. In the meantime, it is important to note that with careful study of the effects of each of these approaches and the costs imposed on the system, the design problem data will be formed. Considering that more effort to improve the reliability of components leads to less redundancy allocation and vice versa, the optimization problem is performed to determine the exact number of redundancies along with determining the exact amount of improvements in complete failure rates. In this research, the satellite attitude determination and control system, the structure of the studied system and its components is introduced, then the reliability in this system is modeled and optimized with a mathematical approach based on the combination of reliability allocation and redundancy allocation.Multi-Verse Optimization algorithm for the Optimal Synthesis of Phase-only reconfigurable linear array of mutually coupled parallel half-wavelength dipole antennas placed at finite distances from the ground plane
http://scientiairanica.sharif.edu/article_22059.html
Researchers on antenna arrays usually neglect the effect of mutual coupling of antennas placed in proximity to each other. The interchange of electromagnetic energy happening between an antenna and a far field point depends not only on the transmitting antenna, but also from its neighbouring antennas. This effect is referred to as mutual coupling between dipole antenna elements and it is considered here in the synthesis of phase only reconfigurable antenna arrays. The main objective of this work is to produce desired Side Lobe Level and Voltage Standing Wave Ratio in addition to few other radiation pattern parameters. Multiverse Optimization algorithm is employed for the purpose of generating voltage amplitude and discrete phase distributions in the dipole elements for the generation of flat-top beam/pencil beam patterns. These two patterns share the common amplitude distributions and differ in phase distributions. Results obtained using MATLAB simulations prove that this algorithm accomplished its task successfully and is also found to be superior over other algorithms like Particle Swarm Optimization, Grey Wolf Optimization and Imperialist Competitive Optimization algorithms.Impact of Measurement Error on Mixed EWMA-CUSUM Control Chart
http://scientiairanica.sharif.edu/article_22060.html
In statistical process control, measurement error plays an important role which is usually ignored. Measurement error can lead to incorrect conclusions about the performance of the process. In this paper, we examined the effect of measurement error on the shift detection ability of the mixed exponentially weighted moving average-cummulative sum (EWMA-CUSUM) control chart. We investigate the performance of mixed EWMA-CUSUM chart in case of mean shift by using (i) covariate method (ii) multiple measurement method (iii) linearly increasing variance method. The performance measuring tools such as average run length (ARL) and standard deviation of run length (SDRL) are estimated by using the Monte-Carlo simulation method. It is concluded that the performance of the mixed EWMA-CUSUM control chart is adversely effected by considering the measurement error. It is revealed from the comparative study that the mixed EWMA-CUSUM control chart is performing better than EWMA and CUSUM control charts in the presence of measurement error. An illustrative example is presented to demonstrate the performance of control charts in case of measurement error.A new traveling-wave-based protection algorithm using intelligent systems
http://scientiairanica.sharif.edu/article_22061.html
A novel traveling-wave (TW)-based protection algorithm for power transmission lines using intelligent systems is proposed in this paper. The first part of the algorithm identifies internal faults from external ones and the other part is used for fault type classification and faulted phases selection. In order to extract TW signals, Teager energy operator (TEO) is used. Then hidden Markov model (HMM) is utilized to identify internal faults from external faults according to the output of TEO. Fault type classification and faulted phases selection are other important tasks in protection algorithms. In this paper, a very accurate and robust classification algorithm based on fuzzy systems is presented. This algorithm uses different ratios of modal components of the faulted current signal as the input variable of fuzzy systems. The test system is simulated in PSCAD software and the algorithm is implemented in MATLAB. Testing the proposed algorithm with a large number of test signals in different fault conditions shows the robustness of both internal fault identification and fault type classification algorithms.The business advantage of identifying and solving pseudo-continuous-integer periodical linear problems
http://scientiairanica.sharif.edu/article_22062.html
Many applications of optimisation require the final value of the decision variables to be integer. In many cases the relaxed optimal solution does not satisfy the integral- ity constraint therefore, the problem must be solved by integer or mix-integer pro- gramming algorithms at a significant computational effort and most likely a worsen objective function value. The contribution of this paper is twofold: The identification of a type of problems in which the relaxed optimal objective function value can be kept in the implementation by a change in the planning horizon; and the identifica- tion of a multi-period based solution procedure. Three small instances are provided in order to illustrate the methodology as well as the economic impact involved. In addition, a fourth industrial size case is included for the benefit of practitioners. This work shows that business profit can be increased for pseudo-continuous-integer periodical linear problems by identifying optimal decision-making periods.Applying SVSSI sampling scheme on np-chart to Decrease the Time of Detecting Shifts - Markov chain approach, and Monte Carlo simulation
http://scientiairanica.sharif.edu/article_22064.html
One of the main criteria for judging about the power of control charts is their ability in fast detection of deviations and shifts in the process. Average time to signal (ATS) or adjusted average time to signal (AATS) are among such criteria calculated under a certain state and assumption. Several studies have shown that using the idea of variable design for control charts, by separating their limits to the safe and the warning regions, can allow quick discovery of shifts and increase sensitivities to small changes. In this paper, a new variable sampling scheme with three sample sizes and two different sampling intervals, called SVSSI, is developed to increase the efficiency of the np control chart. Through various numerical examples, the performance of this scheme is evaluated by calculating ATS and AATS values using Markov chain method. Monte Carlo simulation method is used to validate the results of Markov chain method of SVSSI sampling scheme. In comparison with other schemes, better performance of applying SVSSI is proved in all conditions.Cooperative advertising with two local advertising options in a retailer duopoly
http://scientiairanica.sharif.edu/article_22066.html
This paper considers the issue of cooperative advertising with local advertising options in a channel with three players, including a manufacturer and two retailers. The current study, expands the cooperative advertising literature to a case where there exist two options for local advertising investment. Moreover, this paper compares two cases of presence and absence of cooperative advertising, which has almost been neglected in cooperative advertising literature. The purpose is to determine equilibrium strategy of retailers&rsquo; advertising options, players&rsquo; advertising expenditures and the manufacturer&rsquo; participation rates on retailers&rsquo; investment. The aforementioned problem is analyzed as a three-stage game, using backward induction. In the first and second stages, advertising investments of players are determined analytically. Then, in the third stage, the Nash equilibrium pair of advertising options can be found using numerical study. The problem is solved using illustrative examples in two cases of presence and absence of the cooperative advertising contract. Finally, the conditions for which offering the contract is win-win for all players, are identified. A Sensitivity analysis has been carried out to explain the efficacy of the model.Home Health Care Routing and Scheduling Problem under Uncertainty Considering Patient Preferences and Service Desirability
http://scientiairanica.sharif.edu/article_22067.html
Home Health Care (HHC) is characterized as preparing medical and paramedical services for patients at their place of residence. In the HHC industry, it is imperative for decision-makers to appoint nurses to patients and plan visiting patterns to confront with conflicting objectives and boost service quality. This study offers important insights into Home Health Care Routing and Scheduling Problem (HHCRSP) by dealing with three patient-oriented objectives. Moreover, the proposed model accounts for real-life constraints such as emergency patients, nurses&rsquo; proficiency and patients&rsquo; preferences. Owing to the multi-objective nature of the model, the Augmented Epsilon Constraint approach and Fuzzy Goal Programming are used for trading off the objectives. Further, getting as close as possible to the real-world problems, some parameters are considered uncertain and consequently a robust approach along with three dissimilar uncertainty sets are used to control uncertainty. Numerical results demonstrate that, regardless of the type of the uncertainty set, increasing control parameters make objective values farther than ideal ones, and the comparison performed among the sets also highlights the stringency of the Box space. A unique indicator, presented to validate the robust approaches, features all sets are almost the same in terms of equal optimality and feasibility criteria.Load Shifting Demand Response in Energy Scheduling Based on Payment Cost Minimization Auction Mechanism
http://scientiairanica.sharif.edu/article_22069.html
Demand response (DR) is proven to be very efficacious for load mitigation especially in peak time period. On the other hand, DR facilitates both consumers, system operator as well as producers to moderate their payments while reducing system operating costs. Offer cost minimization is currently used as the clearing mechanism associated with locational marginal pricing scheme to determine the consumers&rsquo; payments. Such clearing and pricing mechanisms are inconsistent as the system costs is being minimized, while the payments are calculated based upon marginal prices. Payment cost minimization auction as a price-based clearing mechanism is envisaged to be an effective alternative to solve such a crucial issue. This paper shows how to include DR in PCM mechanism to further reduce the consumers&rsquo; payment. It facilitates utilizing price responsive consumers for load shifting DR in a PCM auction. The optimization problem is modeled as a mixed-integer nonlinear bi-level programming. Duality theorem, KKT conditions and integer algebra are used to convert such a complicated optimization problem to a single level MILP problem. This problem is then solved by CPLEX in GAMS. The impacts are studied by implementing the proposed formulation to solve the clearing problem in the case studies deriving promising numerical results.An Uncertain Allocation Models in Data Envelopment Analysis: A Case in the Iranian Stock Market
http://scientiairanica.sharif.edu/article_22070.html
Data envelopment analysis (DEA) can be employed for investigating operation and evaluation of units as one of the most important concerns of managers. DEA is a linear programming technique for calculating relative performance of decision-making units (DMUs) with multiple inputs and outputs. Although all inputs and outputs are considered as certain items in these models, there are uncertain items in the real word and existing interference between these two concepts will result in uncertain models. Allocation models were studied in an uncertain environment with belief degree based uncertain input costs and output prices. Belief degree based uncertainty is useful for cases where there is no historical information on an uncertain event. Utilizing the uncertain entropy model as a second objective function, the cost and revenue models showed an optimal performance with a maximum dispersion rate in their constituent components. As a solution methodology, the uncertain allocation models were separately converted into crisp models by expect value (EV) and expected value and chance-constrained (EVCC) methods. A practical example from the Iranian Stock Market was also presented to evaluate the performance of the new model.HUMANITARIAN RELIEF SUPPLY CHAIN PERFORMANCE EVALUATION BY A SCOR BASED TRAPEZOIDAL TYPE-2 FUZZY MULTI CRITERIA DECISION MAKING METHODOLOGY: AN APPLICATION IN TURKEY
http://scientiairanica.sharif.edu/article_22073.html
Determining the most important criteria to evaluate Humanitarian Relief Supply Chain (HRSC) performance is aimed in this study. For this purpose, Supply Chain Operations Reference (SCOR) model is adapted to HRSC. A trapezoidal type-2 fuzzy Analytic Hierarchy Process (T2F-AHP) methodology is proposed to evaluate the criteria influencing the performance of the HRSC, and also evaluate different Non-Governmental Organizations&rsquo; performances operating in Turkey as a real case study. Results of this methodology is aimed to be used by both governmental and non-governmental organizations to improve their HRSC strategies. Lastly, results are discussed with sensitivity analysis to demonstrate the feasibility and applicability of the proposed methodology.Coexistent scheduling in the tandem flow path configuration of a flexible manufacturing system by using an advanced grey wolf optimizer
http://scientiairanica.sharif.edu/article_22074.html
The use of material handling robots (MHRs) for efficient material handling operations in the flexible manufacturing systems (FMS) has gained wide popularity and acceptability across the automated production industries. The coexistent scheduling between jobs and MHRs improves the overall efficiency of the FMS significantly. In the present study, the coexistent scheduling between the MHRs and the jobs under production in the FMS is carried out by using an advanced grey wolf optimization (AGWO) algorithm. The proposed FMS layout is made up of the tandem flow path configurations for the movements of MHRs. The FMS constitutes six flexible manufacturing cells (FMCs) partitioned in six zones and served by six MHRs deployed in each partitioned zone for efficient material handling operations. To develop the coexistent schedule between MHRs and jobs, a combined objective function is formulated by combining the two diverging objectives and solved by using the AGWO algorithm. The combined objective function yield for coexistent production scheduling in FMS, operating with nineteen work centers (WC) and six MHRs to produce thirty-six types of jobs and sixty-six types of jobs in varying batch production quantities is also reported in the paper.Heat and Electricity Supply Chains Expansion Planning Under the Umbrella of Energy Hub: A Case Study of Iran
http://scientiairanica.sharif.edu/article_22075.html
Increases in tightening the correlation of gas and electricity systems (G&amp;ES), affected by diverse factors, ranging from anthropogenic climate change to the advent of new conversion/generation technologies, have remarkably brought the co-expansion of G&amp;ES using a new concept, the so-called Energy Hub (EH), as well as the potential of storage systems into focus. To assess the effectiveness of EH approach and the role of storage systems in the coordinated plans of G&amp;ES, this paper proposes a comprehensive EH-based planning model for co-expansion of G&amp;ES supply chains with respect to the role of gas storage systems (GSSs). As a mixed-integer linear programming (MILP) problem, the model is applied to a real large-scale case study, i.e. the Iranian G&amp;ES and is solved via GAMS package. The simulation results reveal that incorporation of the interactions existing between G&amp;ES into their planning problems in the framework of an EH can reach more flexible, realistic and optimal expansion plans compared with their traditional integrated expansion planning methods. Furthermore, findings show that the involvement capacities of GSSs provides the opportunity of optimal matching of demand with supply by increasing the productivity of the gas pipelines, allowing technically and economically sensible long-term management of gas supply systems.Bitcoin Price Prediction Based on Other Cryptocurrencies Using Machine Learning and Time Series Analysis
http://scientiairanica.sharif.edu/article_22083.html
Cryptocurrencies, which the Bitcoin is the most remarkable one, have allured substantial awareness up to now, and they have encountered enormous instability in their price. While some studies utilize conventional statistical and econometric ways to uncover the driving variables of Bitcoin's prices, experimentation on the advancement of predicting models to be used as decision support tools in investment techniques is rare. There are many different predicting cryptocurrencies' price methods that cover various purposes, such as forecasting a one-step approach that can be done through time series analysis, neural networks, and machine learning algorithms. Sometimes realizing the trend of a coin in a long run period is needed. In this paper, some machine learning algorithms are applied to find the best ones that can forecast Bitcoin price based on three other famous coins. Second, a new methodology is developed to predict Bitcoin's worth, this is also done by considering different cryptocurrencies prices (Ethereum, Zcash, and Litecoin). The results demonstrated that Zcash has the best performance in forecasting Bitcoin's price without any data on Bitcoin's fluctuations price among these three cryptocurrencies.Vehicle Speed and Dimensions Estimation from On-Road Cameras by Identifying Popular Vehicles
http://scientiairanica.sharif.edu/article_22084.html
One of the major issues related to traffic monitoring systems is analyzing the behavior of vehicles and identifying their characteristics. In this paper, an automated algorithm is proposed for calibration of the road cameras. This calibration is used to estimate the speed and dimensions of the passing vehicles. In this method, a motion plane is obtained in the initial frames according to the direction of moving vehicles. After modeling the background, removing shadows, and identifying the exact boundaries of passing vehicles, a number of common vehicles are recognized by the Bag of Words method. Given the actual metric dimensions of these vehicles and the equivalent dimensions on the motion plane, the metric coefficients are calculated and the calibration process is completed. Each passing vehicle is projected on the motion plane, and speed and dimensions are calculated by tracking it along the road. To test the accuracy of the proposed method, we constructed a ground-truth video dataset, by simultaneous capturing the road vehicles using RGB and speed cameras. Furthermore, to identify common vehicles, a dataset of vehicle images was collected. The proposed method evaluated on our dataset and the mean error of 1.15 km/h is achieved. Accordingly, it outperforms previous methods.A DC Power System Stabilizer Based on Passivity-Oriented DC bus Impedance Shaping
http://scientiairanica.sharif.edu/article_22085.html
High penetration of Power Electronic (PE) converters in DC power grids has caused new stability challenges due to dynamic interactions among a network&rsquo;s subsystems. Dynamic interactions can be avoided by the impedance coordination between the subsystems through the modification of control loops or passive elements inside a grid. Impedance coordination is a very complex and time-consuming task with no adaptations to dynamic changes in a power grid. In this paper, the concepts of dynamic interaction and passivity are explained and combined together to provide an online stability measure in terms of the DC bus impedance characteristics. A novel DC Power System Stabilizer (PSS) is proposed which is connected to a DC bus as a separate module passivizing the bus impedance at non-passive interaction frequencies. The interaction frequencies are detected through a broadband online identification process. The PSS working principle, topology, modeling, and control designs are explained in detail. Finally, the functionality and performance of the proposed stabilizer are validated by simulation results.An alternative expression for the constant c4[n] with desirable properties
http://scientiairanica.sharif.edu/article_22092.html
The constant c4[n] is commonly used in the construction of control charts and the estimation of process capability indices, where n denotes the sample size. Assuming the Normal distribution the unbiased estimator of the population standard deviation is obtained by dividing the sample standard deviation by the constant c4[n]. An alternative expression for c4[n] is proposed, and the mathematical induction technique is used to prove its validity. Some desirable properties are described. First, the suggested expression provides the exact value of c4[n]. Second, it is not a recursive formula in the sense it does not depend on the previous sample size. Finally, the value of c4[n] can be directly computed for large sample sizes. Such properties suggest that the proposed expression may be a convenient solution in computer programming, and it has direct applications in statistical quality control.Scheduling of Hydrothermal System Considering Variable Nature of Water Transportation Delay
http://scientiairanica.sharif.edu/article_22093.html
This paper presents solution of short-term hydrothermal scheduling problem using an algorithm called Grasshopper optimization. The objective of hydrothermal scheduling is to reduce the total cost of generation by optimizing the output of power generation of different thermal and hydro plants for a certain time interval. A non-linear relationship between hydropower generation, net head and rate of water discharge is considered here. The complicated head-sensitive water-to-power conversion and piecewise output limit is also considered. To investigate the performance of this new technique, two test systems have been considered. The simulation results are compared with some well-known optimization methods such as Genetic algorithm, Biogeography based optimization, hybrid Differential evolution with Biogeography based optimization and Grey wolf optimizer algorithm. The simulation results show the superiority of this technique as compared to other well-known optimization methods.Modified Cache-Template Attack on AES
http://scientiairanica.sharif.edu/article_22095.html
While it has been known for a long time that the cache behavior is a powerful source of the information leakage, more realistic attack scenarios have received a lot of attention by the cryptographic community. To develop practical cache-based attacks, there is an increasingly need to automate the process of finding exploitable cache-based side-channels in computer systems. Cache template attack is a generic technique that utilizes Flush+Reload attack in order to automatically exploit cache vulnerability of Intel platforms. Cache template attack on T-table-based AES implementation consists of two phases including the profiling phase and the key exploitation phase. Profiling is a preprocessing phase to monitor dependencies between the secret key and behavior of the cache memory. In addition, the addresses of T-tables can be obtained automatically. In the key exploitation phase, most significant bits (MSBs) of the secret key bytes are retrieved by monitoring exploitable addresses. In this paper, we propose a simple yet effective searching technique which accelerates the profiling phase by a factor of at most 64. To verify the theoretical model of our technique, we implement the described attack on AES. The experimental results confirmed a shorter runtime of the attack in comparison to the original attack.Routing order pickers in warehouses considering congestion and aisle width
http://scientiairanica.sharif.edu/article_22096.html
Due to the importance of routing order pickers, there has been extensive research in the area of routing in warehouses. Still, there are some prominent factors that should receive more attention, as they may provide unsatisfactory services and incur considerable operational costs if ignored. In real-world applications, warehouse configuration, width of aisles, and controlling the vehicle congestion in the aisles greatly influence the efficiency of the routing process. Therefore, this paper proposes a mixed-integer programming model. The model aims to minimize maximum delivery time by finding the shortest pickup and delivery routes of all goods for all vehicles. Since the problem is NP-hard, a Simulated Annealing metaheuristic approach is designed to solve the model in large-size problems. This research contributes to picker routing literature by considering dynamic congestion, narrow and wide aisles, and pickup times and proposing a metaheuristic algorithm. The validation and efficiency of our proposed model are proved by solving some various generated benchmark problems. In summary, the developed route planning mathematical model works effectively for any two-dimensional rectangular layout, and the collision prevention constraints are incorporated in the mathematical model.Stochastic optimization for the carrier selection problem in humanitarian relief
http://scientiairanica.sharif.edu/article_22097.html
In this paper, the carrier selection problem is addressed with the purpose of avoiding shortage regarding vehicle necessity and creating a vehicle rental framework agreement. Achieving in-time delivery of relief supplies to the disaster inflicted areas is of utmost significance in terms of humanitarian relief. We propose a new two-stage stochastic model for determining the pre-disaster and post-disaster decisions in order to delivering relief items to the injured survivors. The pre-disaster phase focuses on determining amount of vehicle in the framework of contracts with suppliers, and deciding an appropriate coverage distance with regards to time and cost. The post-disaster phase aims to respond to the requests made by disaster inflicted areas swiftly and cost-effectively. The proposed MILP model considers a scenario-based approach to handle the uncertainty of demand. The L-shaped algorithm is used to solve this model. A real case study is presented with the aim of demonstrating the efficiency of the model. Moreover, numerical analyses are practiced to illustrate the importance and impact of the cost and the number of vehicle rental contracts in the studied problem. Finally, managerial insights have been presented to assist the relief organization management in making appropriate and efficient decisions.Infection Detection in Cystic Fibrosis Patients based on Tunable Q-factor Wavelet Transform of Respiratory Sound Signal and Ensemble Decision
http://scientiairanica.sharif.edu/article_22098.html
Most adult Cystic Fibrosis (CF) patients frequently suffer from Pseudomonas aeruginosa (PA) infection, which is strongly associated with inflammation, lung destruction, and increased mortality. Diagnosis of PA infection in the primary stage is essential to initiate the treatment and reduce the risk of chronic infection. Sputum culture is the gold standard &lrm;for infection detection, but it is time-consuming. The objective of this study was to suggest and examine a method to decide about PA infection status in CF patients based only on their respiratory sound. Respiratory sounds were recorded from 36 CF patients. Some features which were generated from Tunable Q-factor wavelet transform(TQWT) components, were investigated. The features were fed into Support Vector Machine and also Ensemble classifier. The proposed method achieved an accuracy of 90.3% in identifying PA infection in CF patients. Furthermore, the probability of categorizing respiratory sounds as PA CF decreased significantly after the treatment of PA infection(P-value&lt;0.003). Moreover, the method had a satisfactory performance in the presence of noises and artifacts. The developed method represents a novel approach to the diagnosis of PA infection in CF patients based only on respiratory sound signals, which is a necessary and innovative approach for early diagnosis of PA infection.Detecting factors associated with polypharmacy in general practitioners’ prescriptions: A data mining approach
http://scientiairanica.sharif.edu/article_22099.html
Prescribing and consuming drugs more than necessary is considered as polypharmacy, which is both wasteful and harmful. The purpose of this paper is to establish an innovative data mining framework for analyzing physicians&rsquo; prescriptions regarding polypharmacy. The approach consists of three main steps: pre-modeling, modeling, and post-modeling. In the first step, after collecting and cleaning the raw data, several novel physicians&rsquo; features are extracted. In the modeling step, two popular decision trees, i.e., C4.5 and Classification and Regression Tree (CART), are applied to generate a set of If-Then rules in a tree-shaped structure to detect and describe physicians&rsquo; features associated with polypharmacy. In a novel approach, the response surface method (RSM) as a tool for hyper-parameter tuning is simultaneously applied along with correlation-based feature selection (CFS) to enhance the performance of the algorithms. In the post-modeling step, the discovered knowledge is visualized to make the results more perceptible, then is presented to domain experts to evaluate whether they make sense or not. The framework has been applied to a real-world dataset of prescriptions. The results have been confirmed by the experts, which demonstrates the capabilities of the data mining framework in the detection and analysis of polypharmacy.Statistical Adjustment and Calibration of Complex Systems considering Multiple Outputs: Case Study of Laser-Assisted Micromachining Process
http://scientiairanica.sharif.edu/article_22112.html
By rapid advancements in technologies, studying and simulating a complex system with uncertain parameters is too demanding. Based on the literature, there are three approaches to identify and simulate different systems: engineering, statistical, and engineering-statistical approaches. The purpose of this study is to apply the engineering-statistical approach to calibration and adjustment of a Laser Assisted Micro-Machining (LAMM) process with two correlated outputs which are basically known as cutting and thrust forces. This paper contributes to the existing literature by extending the most relevant approach of the calibration of single-output complicated processes to multi-output settings where discrepancy function is modeled by a multivariate Gaussian process and multivariate analysis of variance is used to identify variables whose adjustment benefits the most. For the best case reported in previous studies, Mean Squared Prediction Error (MSPE), as the comparison index, was reported around 1.48 for thrust force whereas the proposed approach resulted in a better value of 1.9425&times;10-4. Moreover, for cutting force output, the index was obtained as 0.21 by the Kennedy and O&rsquo;Hagan, 1.41 by Roshan and Yan, and 1.6&times;10-8 by the presented model. These values demonstrate reasonable and comparable results for the MSPE, in comparison with the models considering the outputs individually.Acceptance sampling plan using new truncated Weibull-X family based on run lengths of conforming items
http://scientiairanica.sharif.edu/article_22113.html
In this paper, we develop two acceptance sampling plans where the lifetimes of the product follow Weibull Exponential and Weibull Lomax distributions both belonging to the new truncated Weibull&ndash;X family of distributions based on run lengths of the conforming items. The model parameters are estimated by using the maximum likelihood method contrary to the existing plans where authors have been selecting arbitrary values of the parameters. The efficiency of the proposed plan is established by comparing it with the existing plans based on the average number of inspected items. A real example of failure rates of a piece of electronic equipment operating in a specific mode is presented to illustrate the proposed plans for industrial use.Adaptive Sliding Mode Control for Multi-machine Power Systems under Normal and Faulted Conditions
http://scientiairanica.sharif.edu/article_22114.html
This paper proposes a new adaptive sliding mode (ASM) decentralized excitation controller to improve the stability of multi-machine power systems under different perturbations such as system&rsquo; parametric and structural uncertainties. The stability of the closed-loop system is proved by Lyapunov stability theory. The proposed controller is evaluated through simulation on the standard IEEE 33-bus-bar power system which contains 6 synchronous machines and a HVDC-link. The simulation results indicate good robustness and satisfactory performance of the proposed controller. Moreover, in this paper, using the space-phasor based sequence networks method, a procedure for the dynamic analysis of modern power systems under the transient asymmetrical faults is presented. The method considers the complete dynamics of the synchronous machines and the HVDC-link and provides the possibility of taking into account the sequence networks dynamics.Delayed LMS filters suppressing the RFI in cosmic rays radio detection
http://scientiairanica.sharif.edu/article_22121.html
The emission of radio waves from Extensive Air Showers (EAS), initiated by ultrahigh-energy cosmic rays, has been attributed to geomagnetic emission and charge excess processes. At frequencies from 10 to 100 MHz this process leads to coherent radiation. Nowadays, the radio detection technique is used in many experiments consisting in studying EAS. One of them is the Auger Engineering Radio Array (AERA), located at the Pierre Auger Observatory. The frequency band observed by the AERA radio stations is 30-80 MHz. This investigated frequency range is often highly contaminated by human-made and narrow-band radio frequency interferences (RFI). The suppression of this contamination is crucial to lower the rate of spurious triggers. An adaptive filter based on the Least Mean Squares (LMS) algorithm can be an alternative to the currently used IIR-notch non-adaptive filter. The paper presents 32/64-stage filters based on a non-canonical FIR filter implemented into cost-effective CycloneIV and CycloneV Altera FPGAs with a sufficient safety margin of the registered performance for a global clock above 200 MHz to satisfy the Nyquist criterion.Multiclass Appliance Scheduling for Cost-effective Energy Management with Constraint and User Preferences
http://scientiairanica.sharif.edu/article_22122.html
For decades, the electrical power grid worldwide has transformed from traditional to the smart power grid, focusing on its transparency to both utility and consumer. The energy management systems play a substantial part in demand response within the smart power grid umbrella, enabling demand-side management at the residential level. These systems generate the consumption profile of appliances and reduce the burden on end-user in scheduling appliances operations. With these consumption profiles of past usage, there is a possibility to generate a time window containing user preferable time slots for appliance operation for the next day. Using this time window, one can generate a cost-effective schedule-pattern autonomously. In this regard, this article proposes a home energy-demand management scheme consisting of a time window generator and a schedule-pattern generator to generate a cost-effectively comfortable schedule-pattern with demand threshold constraint. Multi-class appliances home enabled with a net-meter demonstrate the proposed approach's effectiveness. The simulation results showcase that the proposed approach helps the user to save electricity bills with constraint preserving comfort.Optimal Electromagnetic-Thermal Design of a Seven-phase Induction Motor for High-Power Variable-Speed Applications
http://scientiairanica.sharif.edu/article_22123.html
Induction motors have been traditionally used in industrial applications ranging from a fraction of horse-power up to several Megawatts due to their substantial benefits. Induction drives with more than three-phases are superior to the 3-phase induction drives in terms of overall-volume, torque fluctuations, current passing each stator-winding, ohmic-loss, efficiency and reliability in the case of stator-windings open-circuit fault. These benefits are especially more attractive in variable speed drivers due to the reduced capacity of power-electronics switches. This paper aims to develop an optimal electromagnetic-thermal design procedure of a high-power seven-phase induction motor suitable for variable-speed applications. In this multi-objective design approach, the objective function is defined aiming to increase the efficiency, power-factor, power-to-weight ratio, starting-torque as well as decrease the starting-current. Furthermore, the electrical, mechanical, dimensional, magnetic and thermal limitations are included in this optimization study in order to ensure practical realization of the designed machine. The coupled-circuit method is employed for nonlinear electromagnetic modeling while the current displacement phenomenon is considered in rotor parameters calculations. A lumped-parameter-thermal model is established for calculating heat rises of different parts in each iteration of optimization study. Finally, the performance characteristics of the optimally designed 1-MW 4-pole motor are verified using 2D-FE analyses.Designing a bi-objective rice supply chain considering environmental impacts under uncertainty
http://scientiairanica.sharif.edu/article_22125.html
Rice is a strategic commodity in the food chain for the people and governments. It is a fundamental food for many societies. Moreover, producing rice can provide a reliable source of revenue if proper supply chain management is coordinated by farmer countries. The rice supply chain includes diverse elements such as farms, rice mills, distribution centers, and markets. This study examines the important factors that play a significant role in the rice supply chain. A bi-objective mathematical model is formulated to minimize total costs as an economic goal and minimize soil erosion and its destruction due to the consumed water for rice cultivation as an environmental goal. To verify the proposed model, a case study of the rice supply chain with limited producer farms has been investigated. Moreover, some parameters such as annual precipitation in production areas along with other factors are presented under several scenarios. Furthermore, an extended goal programming approach and stochastic programming are utilized to solve the proposed model. Finally, the sensitivity analyses of the important parameters have been performed.Reliability Optimization of a k-out-of-n Series-Parallel System with Warm Standby Components
http://scientiairanica.sharif.edu/article_22126.html
In this research, a new hybrid model for the redundancy allocation problem (RAP) in a series-parallel configuration with the k-out-of-n subsystem is presented. In the given model, the redundancy policy is set to an active, warm standby, or no redundancy. In warm standby policy, an imperfect switch detected the component's failure and replaced the fail component with a new standby one. So, the subsystems' redundancy policy is one of the model's decision variables. We presented a new objective function for the RAP to calculate the reliability of a system that consists of active and warm standby subsystems. The presented model aims to determine the subsystems' redundancy policy, the type and number of redundant components to maximize the system's reliability, under the system's cost, volume, and weight constraints. To solve the proposed model, we used two Genetic Algorithm (GA) and hybrid GA (HGA) meta-heuristic algorithm with local search. Since the %RPD of HGA is 2.1% (on average) better than GA in solving ten large-scale instances, the result shows the superiority of HGA in comparison with GA for solving the presented RAP.Design Optimization of a Low Speed Small Scale Modular Axial Flux Permanent Magnet Synchronous Generator for Urban Wind Turbine Application
http://scientiairanica.sharif.edu/article_22128.html
Small wind turbines can generate clean energy in diverse locations, from urban centers to rural areas without access to the main grids. This study proposes design optimization of an axial flux permanent magnet (AFPM) synchronous machine for small scale portable applications. At first, a fast, accurate and pragmatic hybrid analytical model is proposed for performance prediction of the machine. The proposed model is then used as a basis for a direct search optimization process with factual constrains and objective functions to improve the machine in terms of efficiency, weight and to ease the manufacturing process. 3 Dimensional Time Stepping Finite Element Method (3-DTSFEM) is utilized to validate the accuracy and effectiveness of the proposed model and optimization methodology. Output characteristic of the machine from both analytical model and 3-DTSFEM are compared to each other that proves the functionality of the proposed study.Analytical Method to Optimum design of Synchronous Reluctance Motor for Electric Scooter Application
http://scientiairanica.sharif.edu/article_22129.html
In recent years, synchronous reluctance motor (SynRM) has attracted the attention of researchers and well-known companies have been involved in designing and manufacturing electric motors due to its simplicity (no need for a rotor cage and permanent magnet), the similarity of its production line analogous to that of the induction motor, low production cost and also, compared to the induction motor, better performance, if optimally designed. Saliency ratio, defined as the ratio of the d axis inductance to the q axis inductance, is the most important parameter in designing a synchronous reluctance motor which has a major impact on achieving both maximum power factor and maximum torque. The current study aimed to provide a comprehensive approach to design a series of synchronous reluctance motors using both combined methods and finite element analysis to achieve an algorithm which is based on the similarity between flux lines and the shape of flux barriers to achieve both maximum torque and minimum torque ripple. The designed motor is intended to be used in an electric scooter application. Therefore, the geometrical dimensions of the motor, such as the motor stack outer diameter and length, are held constant in all cases.Retract-Complete Similarity Measure Mathematical Model For Cell Layout Design
http://scientiairanica.sharif.edu/article_22138.html
The presented mathematical model is used to form machine cells, optimize costs of exceptional elements and design the shop floor layout for various demands of components. The complete similarity measure algorithm forms machine cells and part families in a refined form. Later, exceptional elements are eliminated in linear programming optimization model by using machine duplication and part subcontract. Then the shop floor layout is designed to have optimized material movements between cells and within a cell. The performance evaluation of cell formation algorithm is done on case studies of various batch sizes to give the process capability compared with other similar methods. The result from a linear programming optimization model is cost savings, machines duplicated, parts subcontracted, inter intra cellular movements. Finally, the output of inbound facility design is the floor layout which has machine cell clusters with optimized floor area.Designing of a Mat-heuristic Algorithm for Solving Bi-level Optimization Problems
http://scientiairanica.sharif.edu/article_22140.html
In this paper, a new algorithm for solving bi-level optimization problems is presented. This algorithm can obtain the optimal or near-optimal solution for any bi-level optimization problem. The decision variables of the first and second level models can be both integers and continuous. In this method, by solving a certain number of the bi-objective programming model and then solving the corresponding second-level model, a bi-level feasible solution that is either optimal or near-optimal is identified. To evaluate the efficiency of the algorithm, the value of the objective function, as well as its computation time in different instances, are compared with exact methods as well as evolution-based methods. The numerical results confirm the high efficiency of the proposed algorithm.A Quantitative Measure for Financial Resilience of Firms: Evidence from Tehran Stock Exchange
http://scientiairanica.sharif.edu/article_22141.html
Recent financial crises have strained the performance of different firms and it has challenged investors to invest in the stocks of these firms. Measuring the resilience of firms from a financial standpoint in terms of crises is an important indicator for investors. It is logical that investing in firms with higher historical financial resilience is more attractive for investors. In the literature the resilience is defined as the ability of anticipating, preparing, responding and adapting to incremental change and sudden disruptions in order to survive and prosper. In this paper, the concept of financial resilience has been studied from various dimensions and its quantification approaches are examined. The models developed in this paper are for calculating financial resilience in terms of key indicators, Value at Risk (VaR), and Conditional Value at Risk (CoVaR). Then, by comparing each of these methods, it has been tried to verify the methods by applying quantitative data of four bankrupt and four non-bankrupt firms listed on Tehran stock exchange (TSE) in recent years. The results show the proper performance of the proposed measure in expressing the concept of financial resilience in critical conditions.Stackelberg models in two-level supply chain with imperfect quality items with allowable shortages
http://scientiairanica.sharif.edu/article_22156.html
Application of an absolute supply chain model does not invalidate the possibility of few defective items in a supplied lot, therefore it becomes essential to conduct an inspection process for segregating the defective items, subsequently such segregated items are sold at discounted price. Shortages mainly occur with sudden demand or erratic production capacity, and player&rsquo;s decisions are influenced by it. In this paper, the shortage is considered as a seller&rsquo;s decision variable and demand is receptive to selling price and marketing expenditure of the buyer. Player&rsquo;s interaction will be reviewed and determined as non-cooperative Stackelberg game. Further, a supply chain model is endured to substantiate the interaction and democracy among buyer and seller in the supply chain and is pitched by non-cooperative game theoretical approaches. The Stackelberg game approach is used in the non-cooperative method where one player acts as leader and another as follower. Hereafter, unanimous numerical examples along with sensitivity analysis are exhibited to compare amidst two different models with and without shortages to demonstrate the significance of the paper.A novel bi-objective model for a job shop scheduling problem with consideration of Fuzzy parameters, modified learning effects and multiple preventive maintenance activities
http://scientiairanica.sharif.edu/article_22157.html
This paper aims at introducing a novel bi-objective model for a Job Shop Scheduling Problem (JSSP) in order to minimize makespan and maximum tardiness simultaneously. Some realistic assumptions, i.e. Fuzzy processing times and due dates involving triangular possibility distributions, transportation times, availability constraints, modified position-based learning effects on processing times, and sum-of-processing-time based learning effects on duration of maintenance activities have been considered, to provide a more general and practical model for the JSSP. Based on the learning effects, Processing times decrease as a machine performs an operation frequently, and workers gain working skills and experiences. In this paper based on DeJong&rsquo;s learning effect a novel and modified formulation has been proposed for this effect. According to the above-mentioned assumptions, a novel mixed-integer linear programming (MILP) model for the JSSP is suggested. The proposed model is first converted to an auxiliary crisp model, given that model is a possibilistic programming, it is then solved by the TH and &epsilon;-constraint methods for small instances, and the results are compared. For medium and large instances, five metaheuristic algorithms, including NSGA-&Iota;&Iota;&Iota;, PESA-&Iota;&Iota;, SPEA-&Iota;&Iota;, NSGA-&Iota;&Iota;, and MOEA/D are utilized, and the results are finally compared on the basis of three performance metrics.A new approach in the DEA technique for measurement of productivity of decision-making units through efficiency and effectiveness
http://scientiairanica.sharif.edu/article_22158.html
So far, numerous studies have been developed to evaluate the performance of decision-making units through DEA technique in different places, but most of these studies have measured the performance of decision-making units by efficiency criteria. The productivity is considered as a key factor in the success and development of decision-making units and its evaluation is more comprehensive than efficiency evaluation. Recently, the productivity has been considered in DEA technique. The productivity in these studies is often evaluated through the productivity indexes. These indexes require at least two time periods and also the two important elements of efficiency and effectiveness in these studies are not significantly evident. There are few studies that measure productivity through efficiency and effectiveness. This few researches also measure the efficiency and effectiveness in two stages separately. So, the purpose of this study is to develop a new approach in the DEA technique in order to measure productivity of decision-making units through efficiency and effectiveness simultaneously, in one stage and interdependently. One case study demonstrates application of the proposed approach in the branches of a Bank. Using proposed approach revealed that efficient branches are not necessarily productive, but productive branches are also efficient.Simulation-Based Optimization using DEA and DOE in Production System
http://scientiairanica.sharif.edu/article_22159.html
Production System (PS) is the process of planning, organizing, directing and controlling the tactical and strategic planning of the different components of the company, to transform inputs into finished products which must be effectively managed.the present study aimed to increasing the efficiency and determining the useful methods to evaluate and optimize the performance in different part of PS. To this end, an integrated Discrete-event Simulation (DES), Design of Experiments (DOE), Data Envelopment Analysis (DEA), and Multi-attribute Decision Making (MADM) models were implemented to analyze and optimize the real PS process. In the case study of the automobile manufacturing industry in Iran, the accurate analysis was applied to the proposed approach and its different aspects were considered as well. The results indicated that the proposed approach is a practical way for evaluating and optimizing the performance of different part of PS, compared to previous models and helps the manufacturing companies to make efficient decisions regarding increasing productivity while decreasing the essential problems.Bundle Pricing, Reservation and Refund Policies in a Two-Level Supply Chain
http://scientiairanica.sharif.edu/article_22179.html
Refunding and bundling reservation are known as two popular methods to increase profit where in recent years have gained attention of researchers. One main application of refunding policy emerges for online product sale methods, where consumers can be refunded by returning goods which are not favorite according to their interest. Examining three scenarios including refunding, bundle reservation and refunding along with bundle reservation policies, we will investigate a model for each corresponding scenario. We try to compare two refund and bundle reservation pricing policies in a two-level supply chain including one manufacturer and one wholesaler, and we provide a combined model including two products. The demand is constant and also the population-related information about the division of the population into two types of consumers, strategic consumers (consumers who can predict the second stage discount) and myopic consumers (consumers who can not predict the second stage discount) are available. In addition, the percentage of consumers who refund the product due to regret, the inability to install the product or other reasons, is constant and is independent of the amount of refund. We show that the combined model is optimal and has a higher profit margin than any other policy alone.A Novel Robust Model for Health Care Facilities Location-Allocation Considering Pre Disaster and Post Disaster Characteristics
http://scientiairanica.sharif.edu/article_22193.html
Health care centers are one of the most important municipal facilities that are directly involved in providing personal and social health. In this paper, a new Robust Mathematical Modeling is simultaneously provided to locate and efficiently allocate healthcare facilities, including different service levels of medical care, concerning the characteristics in normal and disaster situations. Furthermore, to help victims and prevent overcrowding in hospitals and medical centers during disasters, the establishment of temporary and outpatient centers is allowed for emergency provision of basic services. Also, the possibility to send equipment and medical teams to these centers is considered in the proposed model. Since the considered problem is included as NP-Complete problems, to solve the problem, two metaheuristic algorithms, harmony search algorithm and hybrid Tabu search combined with variable neighborhood search algorithm, and a lower bound based on Lagrangian relaxation method are presented. Finally, to examine the proposed algorithms, a number of sample problems are randomly generated in small and large sizes and the results of exact solutions and the lower bound resulting from the Lagrangian relaxation method are evaluated and compared with the results of the meta-heuristic algorithms. The results show the good performance of the proposed algorithms.An integrated maintenance planning, warranty policy, technology level and pricing model considering time value of money in a three-level servicing contract
http://scientiairanica.sharif.edu/article_22194.html
A common way to address customer concerns in the post-warranty period is to provide an extended warranty. Although sometimes the manufacturer is reluctant to offer an extended warranty, an agent takes on this task to maintain market share. In this regard, a three-level-servicing-contract among manufacture, agent and customer is presented in which both warranty period and useful life of the product are considered as function of age and usage. The proposed model considers two approaches to control the number of product failures and reduce cost: (1) the technology level used in manufacturing as an effective factor in product reliability; and (2) non-periodic maintenance activities to maintain the product reliability at an acceptable level. In addition, in this study, to calculate the costs imposed on each side of the contract more accurately, the time-value-of-money is considered in the calculation of financial flows. To illustrate the effectiveness of the proposed approach, three comparative studies are provided. The first comparative study shows the impact of the provision of an extended warranty, while the second comparative study proves the importance of preventive maintenance to reduce costs. The results of the last one show the effect of considering the time-value-of-money in calculating cash flows.Group decision making by a last aggregation approach under interval-valued Pythagorean fuzzy environment for sustainable project decision
http://scientiairanica.sharif.edu/article_22195.html
Interval-valued Pythagorean fuzzy sets (IVPFSs) as enhanced type of Pythagorean fuzzy sets (PFSs) improve the expression of the degrees of membership, non-membership and hesitancy in comparison with intuitionistic fuzzy sets (IFSs). In this paper, to use the advantages of IVPFSs a new group decision-making method is introduced based on linear assignment method (LAM). In this approach, subjective and objective weights of criteria are taken into account. Moreover, the method applies a new ranking method for IVPFSs. To avoid the shortcomings of first aggregation methods, the introduced decision-making approach involves a last aggregation approach. Finally, the method is used in a case study of sustainable project evaluation in order to depict the applicability of this method.A sustainable closed-loop location-routing-inventory problem for perishable products
http://scientiairanica.sharif.edu/article_22197.html
Perishable products may expire if their holding time exceeds their shelf-life. In this study, along with designing a forward flow to distribute perishable products; remained perished products at retailers can be gathered for recycling during distributing fresh products. To mitigate the waste, recycled products are offered to a secondary market. A mathematical model for this Closed-Loop Location-Routing-Inventory Problem (CL-LRIP) is developed by considering multi-compartment trucks, simultaneous pickup and delivery, technology selection, and risk of urban traffic. Based on three sustainability pillars, three objective functions are considered. This way, the interests of the network's three main stakeholders are embedded. The proposed model is solved by the Torabi-Hassini method. Two evolutionary algorithms, including Non-Dominated Sorting Genetic Algorithm-II (NSGA-II) and a new hybrid one, are also developed to solve large-sized cases of the NP-complete problem. Statistical tests show the superiority of the hybrid algorithm in the computational time (CT) metric, which is about 0.4 NSGA-II&rsquo;s CT. The results indicate the importance of closing the network loop for perishable products. Finally, the sensitivity analysis determined that 83.33 % decrease in recycled product&rsquo;s sale price causes 9.08% increase in costs, 2.77% decrease in environmental side-effects, and 5.16% decrease in social objectives, which are significant.Demand-driven condition-based maintenance planning under Markovian deterioration of machine condition
http://scientiairanica.sharif.edu/article_22200.html
In this paper, single product single machine systems under Markovian deterioration of machine condition throughout a specified finite planning horizon are studied. It is assumed that the machine is subject to random failures and that any maintenance activities carried out in a period, reduces the system&rsquo;s potential production capacity during that period. Furthermore, it is assumed that the machine is minimally repaired at failure, and PM is carried out, after inspection, to restore the machine to an &lsquo;as-good-as-new&rsquo; status. The objective of the study is to find the optimal intervals for inspection and preventive maintenance (PM) activities in condition-based maintenance (CBM) planning with a discrete monitoring framework subject to minimize the sum of inspection, PM, minimal repair, and backlog costs. To achieve the goal, a stochastic dynamic programming model that enumerates demand is presented calling the demand-driven CBM model. The numerical results show that this model decreases the total cost significantly that depends on the demand and the unit backlog cost, which is an increasing and a concave function in the unit backlog cost regardless of the initial machine state.A mathematical model for the joint planning of maintenance and safety stock in deteriorating imperfect manufacturing systems
http://scientiairanica.sharif.edu/article_22220.html
In this article, a mathematical model is proposed for the joint planning of maintenance policies and inventory control in a deteriorating production system. A safety stock is maintained to meet the demand during the conduction of maintenance actions and to avoid shortages. The optimal planning of maintenance and inventory improves the productivity of the manufacturing system. In a deteriorating production system, the process has two operational states including in-control and out-of-control states as well as a non-operational state, or failure mode. The time for the transition among the states follows a general continuous distribution. The time duration of maintenance actions is also considered as a random variable. The purpose of this study is to optimize the safety stock level and the time to conduct maintenance actions so that the expected total cost per time unit can be minimized. To verify the efficiency of the model, some numerical examples are solved with a genetic algorithm, and validation is conducted for the solutions. Finally, sensitivity analyses are performed on the critical parameters.A Novel Group-based Secure Lightweight Authentication and Key Agreement Protocol forMachine-Type Communication
http://scientiairanica.sharif.edu/article_22225.html
Nowadays, one of the most important criterions in designing different generations of cellular technology is to handle a large number of heterogeneous devices with high security guarantees. The first significant security issue considered in this field is mutual authentication of the devices and the network and authenticated key agreement between them. Hence, various authentication and key agreement (AKA) protocols were proposed for Long Term Evolution (LTE) and 5G networks. However, each of the protocols suffer from various security and performance problems. This paper proposes a group-based secure lightweight authentication and key agreement (GSL-AKA) protocol for machine-to-machine (M2M) communication. Security analysis and formal verification using the AVISPA tool prove that the proposed protocol overcomes various known security attacks and provides all the considered security requirements. Moreover, performance analysis shows that the communication and computation overheads of the proposed protocol are the lowest in comparison with the other existing group-based AKA protocols.A System Dynamics Model for Evaluating the Firms’ Capabilities in Maintenance Outsourcing and Analyzing the Profitability of Outsourcing
http://scientiairanica.sharif.edu/article_22236.html
Outsourcing is recognized as a tool to gain strategic advantages. Maintenance outsourcing is a common practice in many industries, including chemical, petroleum, petrochemical, and medical equipment manufacturing. Nevertheless, outsourcing is associated with many risks. In the present study, based on the system dynamics, we designed a model to identify variables, influencing the effectiveness of equipment, efficacy, and profitability. We also examined the extent of the effects of these variables and assessed their relationships to decide on maintenance outsourcing in gas refineries. First, the influential variables were identified by reviewing the literature and considering the experts&rsquo; opinions. Next, a system dynamics model was designed, and the optimal values of the variables were investigated by creating five different scenarios. The results showed how the investigated variables affected our goals and how we could achieve them by keeping the values of these variables close to those determined in the selected scenarios. If the variable of equipment effectiveness was preferred by the managers, scenario-3 would be selected, as the equipment effectiveness reached its maximum level in this scenario. On the other hand, if the efficacy and profitability variables were preferred, scenario 4 would be selected in which efficacy and profitability were at maximum levels.Experimental Evaluation of Optimal Tuning for PID Parameters in an AVR System
http://scientiairanica.sharif.edu/article_22237.html
Automatic Voltage Regulator (AVR) is employed to stabilize the output voltage of the generators in the electric power plants. However, reliable performance of AVR depends on professional tuning of its PID controller&rsquo;s parameters. Therefore, different optimization algorithms are used to determine those parameters. The objective of the optimization is defined as minimizing the characteristics of transient step response such as settling time, rise time, overshoot, and steady state error. Then, to verify the optimization results, a simulator is built experimentally for AVR and PID system that can also be used for other studies on AVR systems. The experimental results are compared with those of MATLAB and Pspice Software. Close agreement between the simulation and experimental results confirms the success of the optimization.ParDeeB: A Graph Framework for Load Forecasting Based on Parallel DeepNet Branches
http://scientiairanica.sharif.edu/article_22238.html
Recently, energy demand forecasting has emerged as a signicant area of research because of its prominent impact on greenhouse gases (GHGs) emission and global warming.The problems of load forecasting are characterized by complex and nonlinear nature and also long-term historical dependency. Up to now, several approaches from statistical to computational intelligent have been applied in this research led. The literature agrees with the fact that deep learning approach is more capable in dealing with these characteristics among existing approaches. However, the recent state-of-the-art deep network models are not robust against dierent historical dependency. In this study, we propose a graph framework based on parallel DeepNet branches to tackle this challenge. This framework consists of multi parallel branches in which dierent kind of networks can be incorporated. The parallel recurrent branches represent the historical dependency of determinants individually and this leads to better performance in case of dierent historical dependency in data. In this case study, the performance of the proposed model is examined through a comparison study with the state-of-the-art deep network models. The comparison resulted in that the proposed framework can improve the load forecasting by a signicant margin on average.Honeycomb shaped fractal antenna with dual notch characteristic for UWB applications
http://scientiairanica.sharif.edu/article_22239.html
The paper presents a feasible way to construct the honeycomb structured microstrip antenna for UWB (Ultra Wide-band) applications with dual notch characteristic. The antenna designed based on the concept of initial stage of honeycomb nest construction and Defected ground structure(DGS) with dual notch for Ultra Wide Bandwidth applications. The two notches for WiMAX (3.5GHz center frequency) and WLAN (5.5 GHz center frequency) are introduced by etching two asymmetrical quarter wavelength slots in the ground. The compact antenna of size 12 x 20 mm2 with simple geometry achieves very wide bandwidth of 3.1-13.8 GHz(Covers UWB and higher frequency band) with dual notch characteristic.TQCAsim: An Accurate Design and Essential Simulation Tool for Ternary Logic Quantum-Dot Cellular Automata
http://scientiairanica.sharif.edu/article_22243.html
Having a reliable simulation tool for evaluating the performance of each design is indispensable. Designing multiple-valued logic (MVL) systems help to overcome the limitations existing in binary systems. Quantum-dot cellular automata (QCA) is a technology that can be substituted for CMOS in MVL designs. This paper represents an exquisite software platform for designing and simulating circuits which are restricted to three-valued logic (Ternary) quantum-dot cellular automata (QCA). Working with TQCAsim is so convenient because it can run in both Windows or Linux based computers. It has a tenacious simulation engine that can warranty precise results. This tool shows the results in graphical formats. As well, designers can easily layout their ternary QCA designs by using various sets of CAD tools. In this paper, the ternary model of QCA and its energy calculation will be demonstrated. The simulation Process will be explained step by step. MIN, MAX, NOT, and XOR gates had been simulated already by this software.Efficient scheduling of emergency surgeries by adjusting the schedule of elective surgeries
http://scientiairanica.sharif.edu/article_22244.html
The rapid growth of the population has resulted in an increasing demand for healthcare services, which forces managers to use costly resources such as operating rooms effectively. The surgery-scheduling problem is a general title for problems that consists of the patient selection and sequencing of the surgeries at the operational level, setting their start times, and assigning the resources. Hospital managers usually encounter elective surgeries that can be delayed slightly and emergency surgeries whose arrivals are unexpected, and most of them need quick access to operating rooms. Reserving operating room capacity for handling incoming emergency surgeries is expensive. Moreover, emergency surgeries cannot afford long waiting times. This paper deals with the problem of surgery scheduling in the presence of emergency surgeries with a focus on balancing the efficient use of operating room capacity and responsiveness to emergency surgeries. We proposed a new algorithm for surgery scheduling with a specific operating room capacity planning and analyzed it through a simulation method based on real data. This algorithm respects working hours and availability of staff and other resources in a surgical suite.A modified integer and categorical PSO algorithm for solving integrated process planning, dynamic scheduling and due date assignment problem
http://scientiairanica.sharif.edu/article_22245.html
Particle Swarm Optimization (PSO) has many successful applications on solving continuous optimization problems. It has been adapted to solve discrete optimization problems using different variants, such as integer PSO (IPSO), discrete PSO (DPSO) and integer and categorical PSO (ICPSO). ICPSO, a recent PSO variant, uses probability distributions instead of the solution values. In this study, we applied ICPSO algorithm to solve dynamic integrated process planning, scheduling and due date assignment (DIPPSDDA) problem which is a higher integration level of well-known problems which are integrated process planning and scheduling (IPPS) and scheduling with due date assignment (SWDDA). Briefly, due date assignment function is integrated to IPPS problem as the third manufacturing function in DIPPSDDA. Furthermore, DIPPSDDA performs scheduling function in a dynamic environment in where jobs arrive to shop floor in any time. The objective of DIPPSDDA problem is to minimize the earliness, tardiness and given due dates length. Since the experimental results show that ICPSO does not find better solutions, crossover and mutation operators used in genetic algorithm were implemented to ICPSO, namely modified ICPSO (MICPSO). Finally, experimental results indicate that the proposed MICPSO provides better performance as compared to genetic algorithm, ICPSO and modified discrete PSO.A Novel Basis Function Approach to Finite Population Parameter Estimation
http://scientiairanica.sharif.edu/article_22251.html
Modeling non-linear data is a common practice in data science and machine learning (ML). It is aberrant to get a natural process whose outcome varies linearly with the values of input variable(s). A robust and easy methodology is needed for accurately and quickly fitting a sampled data set with a set of covariates assuming that the sampled data could be a complicated non-linear function. A novel approach for estimation of finite population parameter &tau; , a linear combination of the population values is considered, in this article, under superpopulation setting with known basis functions regression (BFR) models. The problems of subsets selection with single predictor under an automatic matrix approach, and ill-conditioned regression models are discussed. Prediction error variance of the proposed estimator is estimated under widely used feature selection criteria in ML. Finally, the expected squared prediction error (ESPE) of the proposed estimator and the expectation of estimated error variance under bootstrapping as well as simulation study with different regularizers are obtained to observe the long-run behavior of the proposed estimator.A Sustainable Production-Inventory Model Joint with Preventive Maintenance and Multiple Shipments for Imperfect Quality Items
http://scientiairanica.sharif.edu/article_22253.html
The quality of products, maintenance operations, and transportation policies are primary concerns of managers in inventory and production planning issues. Besides that, environmental concerns and regulations are growing increasingly and attracted much attention to green production concepts such as sustainable production. Previous authors conducted a wide range of research on these problems separately. Regarding the gap of an integrated framework, we formulate a sustainable Economic Production Quantity model by considering preventive maintenance and multiple shipments of items where a portion of produced items are defective. Two different Cases are studied. In Case I, we assumed that the demand in the production period is satisfied by the produced items in the previous cycle. In another state and in Case II, simultaneous production and consumption during the production period is considered and mathematically formulated. An analytical method is presented for solving the models, and a numerical example is discussed for both Cases. Moreover, sensitivity analysis of the models is carried out, and some managerial insight is derived by changing some of the critical parameters of models. Finally, we present some directions for feature researches.An Inset-Feed On-Chip Frequency Reconfigurable Patch Antenna Design with High Tuning Efficiency and Compatible Radome Structure for Broadband Wireless Applications
http://scientiairanica.sharif.edu/article_22255.html
A novel, dual edge-shaped frequency reconfigurable antenna with a highly compact size is proposed, using microstrip line-based inset-feed mechanism. The presented antenna uses cost-effective ROGER substrate with a thickness of 0.787 mm and has been studied for its gain and radiation pattern in the radome structure presence. The antenna resonates within the range of 3 GHz to 9 GHz approximately, with maximum tuning efficiency of 43 % at 6.5 GHz, covering the major wireless applications of aviation service and wireless local area network (WLAN) in the upper segment of S-band along with worldwide interoperability for microwave access (WiMAX), long-distance radio telecommunications, and X-band satellite communication. The proposed antenna works resourcefully with a reasonable gain of 2.3 dBi at 5.04 GHz, significant bandwidth of 2800 MHz (maximum at 6.5 GHz), directivity, and reflection coefficient. The proposed multiband reconfigurable antenna along with radome structure using ABS material has been investigated under high-frequency simulation environment of HPEEsof of ADS (by Keysight Technologies) and 3d radiation pattern (far-field gain, directivity and power calculations) have been obtained using momentum and EMDS simulators of ADS. The final implementation size (without radome structure) for the patch design comes out to be 23 mm X 26 mm large.The analysis of bullwhip effect in supply chain based on hedging strategy compared with optimal order quantity strategy
http://scientiairanica.sharif.edu/article_22267.html
The bullwhip effect is one of the most important problems in the supply chain management. It can cause large inefficiency in supply chain. Although there are many researches about bullwhip effect, few studies have investigated this phenomenon caused by product price fluctuation. In this paper we consider a two-period supply chain consisting of one supplier, one wholesaler and one retailer. The wholesale price may increase greatly in the beginning of second period. If this happens, a large number of end customers will go to purchase the product from retailer. For managing the end customers&rsquo; demands in the second period, we consider two ordering strategies available to the retailer including optimal order quantity strategy and hedging strategy with call option. For each strategy, we calculate the bullwhip effect ratio for two periods and compare the results. We found that the lower exercise price in hedging strategy compared with the wholesale price in the optimal order quantity strategy must not contribute to extra product purchase. The research provides new insights into how hedging strategy can reduce bullwhip effect.Chemical reaction, radiation and activation energy effects on MHD buoyancy induced nanofluid flow past a vertical surface
http://scientiairanica.sharif.edu/article_22273.html
This paper explores the effects of thermal radiation, buoyancy force, chemical reaction, and activation energy on magnetohydrodynamic (MHD) nanofluid flow past a stretching vertical surface. The resulting nonlinear momentum, energy, solute, and nanoparticle concentration boundary layer equations are simplified by the transformation of similarity. The transformed equations solved numerically by using the shooting technique. For various related parameters, the corresponding results to the dimensionless velocity, temperature, solute, nanoparticle concentration profiles, Skin friction, local Nusselt number, local Sherwood number, and local nanoparticle Sherwood number are illustrated graphically. It is found that the temperature and nanoparticle concentration profiles increase on increasing thermal radiation and temperature difference parameters. With the increase of the regular buoyancy parameters, the local Nusselt number decreases on increasing the fitting rate constant, Biot number, and thermal radiation parameters.Improvement of Regional-Market Management Considering Reserve, Information Gap Decision Theory and Emergency Demand Response Program
http://scientiairanica.sharif.edu/article_22279.html
There is a variety of items which should be taken into consideration by a regional market manager (RMM). Participants in the market, technical constraint, price variation/reaction, electricity-price uncertainty and types of the applied demand response program are some instances in this regard. One of the demand response programs is Emergency Demand Response Program (EDRP) which is considered in this paper. In the present study, the objective function of the RMM is formulated in a market environment in order to determine the optimal demand, incentive and power purchased with considering some of technical constraints such as incentive limits, demand limits, power purchased and power balance. Co-evolutionary Improved Teaching Learning-Based Optimization (C-ITLBO) is applied to maximize the RMM&rsquo;s profit. Furthermore, determination of the demand level in the EDRP is performed on the basis of a logarithmic model which includes the price elasticity matrix (PEM) is included. The reserve supplied due to Aggregators (AGGs) is also prioritized using the reserve-margin factor (RMF). In addition, information-gap decision theory (IGDT) is applied to model uncertainty in the initial electricity price. The above mentioned items are modeled in a multi-level formulation.Sustainable Model of Port-hinterland Freight Distribution Network Considering Uncertainty: A Case Study of Iran
http://scientiairanica.sharif.edu/article_22281.html
According to the significant role of ports, port-hinterland distribution network considering various parameters, has come under the spot of attention in the recent years. This paper, considering intermodal transport, along with the possibility of constructing new inland terminals where transportation mode changes, aims to investigate the subject of port-hinterland freight distribution network. To this aim, considering the volume of exported freight being delivered as well as imported freight received, a multi-objective intermodal model has been developed for Iran's case study. In this model, it has been assumed that in addition to the existing railway and road routes in the country, new railway and road routes could be constructed as well. The first objective function involves minimizing the cost of transportation along with the cost of constructing an inland terminal. The second objective function involves minimizing CO_2 released during freight transport. The certain model of the problem has been described, first and uncertainty conditions in amounts of import demand and export supply has been taken into account. A robust modeling approach has been used. Therefore, data of goods imported or exported to/from Iran were collected and solved using robust model in GAMS software; then the results were analyzed and investigated.Novel Decision Making Framework Based on Complex q-Rung Orthopair Fuzzy Information
http://scientiairanica.sharif.edu/article_22292.html
The q-rung orthopair fuzzy sets (q-ROFSs) are increasingly valuable to express fuzzy and vague information, as the generalization of intuitionistic fuzzy sets (IFSs) and Pythagorean fuzzy sets (PFSs). In this paper, we propose complex $q$-rung orthopair fuzzy sets (C$q$-ROFSs) as a new tool to deal with vagueness, uncertainty and fuzziness by extending the range of membership and non-membership function of $q$-ROFS from real to complex number with the unit disc. We develop some new complex $q$-rung orthopair fuzzy Hamacher operations and complex $q$-rung orthopair fuzzy Hamacher aggregation operators, i.e., the complex $q$-rung orthopair fuzzy Hamacher weighted average (C$q$-ROFHWA) operator, and the complex $q$-rung orthopair fuzzy Hamacher weighted geometric (C$q$-ROFHWG) operator. Subsequently, we introduce the innovative concept of a complex $q$-rung orthopair fuzzy graphs based on Hamacher operator called complex $q$-rung orthopair fuzzy Hamacher graphs (C$q$-ROFHGs) and determine its energy and Randi\'{c} energy. In particular, we present the energy of a splitting C$q$-ROFHG and shadow C$q$-ROFHG. Further, we describe the notions of complex $q$-rung orthopair fuzzy Hamacher digraphs (C$q$-ROFHDGs). Finally, a numerical instance related to the facade clothing systems selection is presented to demonstrate the validity of the proposed concepts in decision making (DM).A quick solution to optimal coordinated voltage-control, based on dimension-reduction of power system via Modified Ward-PV
http://scientiairanica.sharif.edu/article_22295.html
Voltage control and Voltage stability are the most important issues in the power system. The purpose of this paper is to investigate the emergency voltage control in power systems. One of the most important proposed methods to solve this issue is optimal coordinated voltage control (OCVC), which is based on the model predictive control (MPC). Time limitations for preventing voltage collapse is the most critical constraint to solve an OCVC problem. In this paper, the Modified WARD-PV will be proposed to reduce the dimension of the power system and consequently, the speed of solving problem is increased. In this method, immediately after occurrence a fault, the power system is partitioned to into three subsystems by spectral graph partitioning method. Partitioning is based on reactive power flow through the lines. The subsystems, which are far from fault, will be replaced by the reduced model. This method will drastically reduce the number of system equations and will boost the speed of solving problem. The simulations results obtained on New England IEEE 39-Bus System reveals that the proposed method acts more precise than dimension reduction of power system based on linearization of external subsystems, but the speed of solving problem decrease.An optimization model for evacuating people with disability in extreme disaster conditions: A case study
http://scientiairanica.sharif.edu/article_22296.html
The increasing severity and frequency of disasters have posed major challenges for people. Amongst, the risks of fatalities and injuries of people with disabilities (PWDs) have significantly increased. The Sendai Framework for Disaster Risk Reduction (SFDRR) initiated a movement to create a "disability-accessible and inclusive environment" which highlighted the problems PWDs faced during disasters. One of the most important issues is providing evacuation and accommodation according to the special needs of PWDs. In this study, a MILP model is proposed to pick up PWDs from different locations and transfer them to shelters. Throughout this research, diverse disabilities, heterogonous vehicles, compatibility types of disabilities and vehicles, multi-depot and adept and amateur operators were considered to help evacuate PWDs. Additionally, 27 problems are solved to examine the efficacy of (&mu;+1) EA algorithm in large scale problems. Subsequently, a real case study with 500 nodes including pick up, shelters, and depot nodes are analyzed. The computational results illustrate that by adding small-sized (car) and medium-sized (Van) vehicles to the current fleet, the time for tours traveled significantly reduces. Finally, a sensitivity analysis has been conducted to prepare some managerial implications for crisis managers during the occurrence of disasters to help PWDs during evacuation.A CFD Study of a Flanged Shrouded Wind Turbine: Effects of Various Flange Surface Types on Output Power
http://scientiairanica.sharif.edu/article_22297.html
There is a global trend to optimize energy harvesting from all energy resources including renewable energy. In this study, the focus is on improving the surface of flanges in flanged shrouded wind turbines to obtain more efficient systems. A CFD approach is utilized for this purpose. All models are identical in the entrance diameter, exit diameter, length of the diffuser, and the height of the flange, but each model is of a different flange surface type. Different surfaces are studied, including a simple surface and some furrowed surfaces. The validation reports that there is a strong correlation between the present study's outcomes and that of previously experimental results. The results show that the models with furrowed surface flange type lead to an increase in the wind velocity when approaching the wind turbine blades. This leads to about 5-7% more output power. Also, the results indicate that the maximum velocity occurs at about 5cm after the shroud entrance. Consequently, it is suggested that the wind turbine should be installed at that location inside the shroud, to obtain the optimum energy harvest.Angle Design of Stator-Rotor Blades for VLH Axial Flow Turbine using Surrogate-based Optimization
http://scientiairanica.sharif.edu/article_22339.html
This paper demonstrates design of a Very Low Head axial flow turbine using surrogate-based optimization. The design variables were blade angles between guide vanes and runner blades, whereas the objective function was turbine efficiency. A Latin Hypercube Sampling method was initially used to design the experiment with thirty sampling points, and a Large Eddy Simulation was modeled to analyze the flow for all sampling points. A correlation between design variables and the turbine efficiency was then evaluated using the surrogate models while the optimal design variables were identified. Also, several optimizers were used to tackle the proposed problem and their performances were investigated. The optimal design of blade angles \mathbit{\beta}_\mathbf{1}-\mathbit{\beta}_\mathbf{8} being 10o, 20o, 30o, 40o, 25o, 45o, 55o and 65o respectively, increased the turbine efficiency up to 89.87 %. The approach of using surrogate modeling was proved to be very effective and simple for optimizing a design of blade angles of stator-rotor and it can be applied for designing any other new blades.Relative agreement method for multiple criteria decision making problems with interval numbers
http://scientiairanica.sharif.edu/article_22343.html
So far, many ways have been provided to solve multiple criteria decision making problems with interval numbers. Most of these methods rank the alternatives according to two criteria, that is, being close to the positive ideal solution and far away from the negative ideal solution. In this paper, a method is presented for solving multiple criteria decision making problems with interval numbers, such that being close to positive ideal solution and being away from negative ideal solution have the same effect in alternatives ranking. In the proposed method, the first positive ideal solution and negative ideal solution are determined as interval numbers and distance of each alternative from positive ideal solution and negative ideal solution is calculated by extension of Euclidean distance. Then, a compromise index is defined to rank the alternatives. Three numerical examples are given to compare the proposed method with other methods presented in the literature.A Combinatorial Optimization Solution for Activity Prioritizing Problem
http://scientiairanica.sharif.edu/article_22344.html
This paper discusses a special situation in project management in which an analyst wants to prioritize several independent activities to handle all them one after another, in such a way that there are no precedence relationships over the activities. As a novel idea, in this research, the notion is that the structure of prioritized activities is a linear arrangement, and therefore it could be taken into account as a combinatorial optimization problem. The paper formulates a mathematical model, develops a row-generation solving procedure, and reports the computational results for the problem instances of size up to 300 activities. The results demonstrate the applicability and efficiency of the proposed methodology.A Quasi 3D Modified Strain Gradient Formulation for Static Bending of Functionally Graded Micro beams Resting on Winkler-Pasternak Elastic Foundation
http://scientiairanica.sharif.edu/article_22345.html
This paper presents the bending analysis of simply supported functionally graded (FG) size dependent beams based on modified strain gradient theory. The shear and normal deformations are considered in displacement field according to hyperbolic shear deformation theory. Governing equations and corresponding boundary conditions for FG micro beam are derived utilizing principle of minimum total potential energy. Mori&ndash;Tanaka homogenization scheme and the classical rule of mixture are used for prediction of material properties through the thickness. Effects of Winkler-Pasternak elastic foundation parameters are studied for different side to thickness ratios. Effects of different aspect ratios, elastic foundation parameters, power law gradient indexes and different loading conditions are investigated. The efficiency and accuracy of present model is demonstrated by comparing to the existing results in especial cases.Facility Disruptions in a Closed-loop Supply Chain Featuring Warranty Policy and Quality-based Segmentation of Returns
http://scientiairanica.sharif.edu/article_22353.html
This paper focuses on a closed-loop supply chain that deals with disruptions in the distribution centers, and optimizes the network in two dimensions of sustainability: economic and environmental. Economically, the proposed network maximizes the profits of the customers, manufacturers and distributors. Three avenues for cost minimization are designed for the customer by adding the warranty periods, the reworking options, and the incentives for returning the used items. Non-dominated solutions via the Reservation Level-driven Tchebycheff procedure are found by appropriate choice of facility establishment and suitable allocation links considering the disruption in the distribution centers.Environmentally, the model adopts a zero-waste strategy by embedding various return-segmentation policies and a secondary chain. The backward flow depends on the customers' choice of reworking, the validity of the warranty contract, and the quality of the returns. The test results indicate that due to various revenue options, the manufacturing and distribution centers prefer returns with medium-range quality, while due to the incentives offered for the recyclable items, the customers benefit the most from returning the items with the lowest quality. The tests on the probability of disruptions indicate that establishing a minimum number of the manufacturing and/or distribution sites without disruption leads to better overall performance.Alkali Activated Cedar Wood as an Efficient Adsorbent for Pb2+ Removal from Aqueous Solutions: Optimization, Kinetic and Thermodynamic Study
http://scientiairanica.sharif.edu/article_22355.html
In the present study, activated carbon prepared from cedar wood was synthesized, &lrm;via NaOH activation, and optimized to be used as the adsorbent for Pb2+ removal &lrm;from aqueous solutions in a batch process mode. The physicochemical properties &lrm;of the synthesized adsorbent were examined by SEM, FTIR and BET analysis. In &lrm;order to determine the optimum operational conditions, the effects of different &lrm;parameters including pH, adsorbent dosage, contact time, temperature, and initial &lrm;Pb2+concentration on the adsorptive performance of synthesized samples were also &lrm;investigated. According to the obtained results, the highest Pb2+ ion adsorption &lrm;capacity (971.9 mg/g) took place at the optimum operational condition of pH=4, &lrm;adsorbent dosage of 0.025 g/L, contact time of 60 minutes, 300 ppm of Pb2+ and &lrm;&lrm;30 ℃. The results showed that among Langmuir, Freundlich, and Temkin &lrm;isotherms, the obtained data were fitted the best with the Freundlich model. &lrm;Additionally, the process of Pb2+ adsorption was consistent with the pseudo-&lrm;second-order kinetics model, indicating that chemical adsorption was the dominant &lrm;mechanism of adsorption. Finally, according to the calculated thermodynamic &lrm;parameters, i.e., ∆H&deg;, 〖∆S〗^&deg; &amp; 〖∆G〗^&deg;, Pb2+ adsorption on activated cedar &lrm;wood can be considered as an exothermic and spontaneous process.&lrm;Short Free-Standing Pole LED Luminaire and Lens Design for Road Lighting
http://scientiairanica.sharif.edu/article_22356.html
Road luminaries are required to provide the luminance specified in the standards according to the road characteristics. For this reason, the light from the light source should be directed according to the desired conditions. While the range of minimum average road surface luminance recommended for different classes of road are provided; at the same time, it is desirable to be economical. In this study, a freeform lens and LED luminaire design with high luminous efficacy, low glare and uniform luminance distribution with a height of 1.5 m and a distance of 7 m between poles were designed for M3 road standards. First of all, lens design was made by using optical and illumination design software. Also, lens manufacturing and luminaire production were made as a result of the success of the design simulation test. The success of the LED luminaire in providing CIE standards has been measured on the designed road. In addition, the advantages and disadvantages have been determined by comparing with High Pressure Sodium Vapor (HPS) lamps.Three dimensional prediction of stability lobes in end milling of thin-walled structures based on tool and workpiece dimensions
http://scientiairanica.sharif.edu/article_22357.html
Nowadays, researchers are very interested to investigate the dynamic behavior of the thin-walled structures during the machining process due to their broad application in aerospace, automotive industries and etc. One of the main problems in machining of thin-walled structures is unstable chatter vibrations, which causes the poor machined surface quality and decreases the system life span. In this regard, the main aim of this paper is to propose a practical method to solve the chatter instability problem during the milling process of thin-walled components. To this end, first the effects of geometrical parameters like workpiece height, thickness, and tool overhang, diameter and their ratios on the chatter stability are investigated. Then three dimensional stability lobe diagrams (SLDs) base on the mentioned parameters are presented for the first time. In which one can implement the mentioned diagrams to switch the unstable machining process to stable one by changing the value of the system parameters. Finally, the results obtained by the experimental test show that the presented three dimensional diagrams can be utilized to avoid chatter instability in the milling process.Minimizing the Casting Defects in High Pressure Die Casting Using Taguchi Analysis
http://scientiairanica.sharif.edu/article_22359.html
High-Pressure Die Casting (HPDC) is one of the major production processes of automotive industry, widely used to manufacture geometrically complex nonferrous castings. The mechanical strength and microstructure of HPDC-manufactured products changes with variation in several process control parameters such as injection pressure, molten temperature, 1st and 2nd stage plunger velocity, cooling temperature, etc. Since these process parameters directly affect casting quality, their optimum combination is needed to maximize the productivity of process and minimize casting defects such as porosity, pinholes, blowholes, inclusions, etc. Hence, to tackle this problem, an approach is presented in this paper that minimizes the major casting defect, i.e., porosity, in the HPDC process by optimizing controlling parameters through Design of Experiments (DOE) in combination with a Taguchi Analysis. The results obtained showed that cooling time, injection pressure, and 2nd stage plunger velocity have a major influence on the response factor (density of the cast part). It was also concluded that, by using a 178 bar injection pressure, 665 &deg;C molten temperature, 5 second cooling time, 210 &deg;C mold temperature, 0.20 m&middot;s&minus;1 1st stage plunger velocity, and 6.0 m&middot;s&minus;1 2nd stage plunger velocity, the rejection rate of the selected part due to porosity was reduced by 61%.A combined approximation method for nonlinear foam drainage equation
http://scientiairanica.sharif.edu/article_22360.html
The aim of this study is to develop a combined approximative technique to find a numerical solution to the foam drainage equation arising in various absorption and distillation processes. In this approach, first, the discretization of time is performed with the aid of the Taylor expansion series. Hence, a collocation method based on novel Bessel polynomials is utilized for the space variable. Thus the solution is found by solving a linear system of algebraic equations at each time step in contrast to solving a nonlinear system. Numerical simulations are provided to check the accuracy and efficiency of the presented algorithm. The numerical results are compared with exact solutions as well as with the outcomes of other existing available numerical methods.Terahertz Linear to Circular Polarization Converter Based on Reflective Metasurface
http://scientiairanica.sharif.edu/article_22361.html
Metasurfaces are two-dimensional artificial structures which have extraordinary electromagnetic properties. They have been used in myriad of devices such as nano-antennas, cloaking coatings, imaging devices, flat lenses, and polarization converters over a wide range of frequency. Due to high dependency of many devices on incident wave polarization, manipulating the polarization of electromagnetic waves would be useful, especially in the THz regime. In this study, we propose a linear to circular polarization converter (LTC-PC) based on a THz reflective metasurface. For a TE linear polarization incident wave, this structure has two distinct bands; the first one lays in a wideband frequency range of 0.5-1.41 THz, in which the reflected wave would be a left-handed circular polarization (LHCP) with minimum efficiency of 89% and maximum efficiency of more than 95% in 80% of the bandwidth. The second band lays in the narrowband frequency range of 1.45-1.55 THz, resulting a right-handed circular polarization (RHCP) wave with a minimum efficiency of 82%. The proposed polarization converter can be used in optical communication and electronic devices.Taguchi Optimization of Fused Deposition Modeling Process Parameters on Mechanical Characteristics of PLA+ Filament Material
http://scientiairanica.sharif.edu/article_22362.html
This study was realized to determine effects of Fused Deposition Modeling (FDM) process parameters on mechanical characteristics with Taguchi optimization method. Three different FDM process parameters used for modified Polylactic Acid (PLA+) filament material; filling structures (Rectilinear, Triangular, and Full Honeycomb), occupancy rates (10, 30, and 50 %) and table orientation (0, 60, and - 45&deg;) was specified as variable parameters for experiments. Other parameters kept fixed for each tensile and izod impact test samples were printed according to the ISO 527 &ndash; Type IV and ISO 180-Type I standards. The results found tensile strength values and izod impact values directly proportionate with occupancy rate. The difference between the estimation model and the results of experiments did not exceed the maximum value of 1.8 %. Thus, using the equations derived from this optimization, printing parameters can be determined for the desired tensile strength and izod impact values. By improving the material properties using modified PLA+ filament material as observed in the results, it will be possible to provide support for researchers, design engineers and manufacturer to optimize raw-material usage and margin.Circularly polarized truncated corner Square slot antenna for Ku- Band applications
http://scientiairanica.sharif.edu/article_22363.html
The communication presents a novel microstrip line-fed compact square slot circular polarized antenna for Ku-band applications. The proposed square slot antenna with circular trimmed corners is fabricated on the FR-4 substrate with the defected ground on the opposite side of the patch. The axial ratio bandwidth (ARBW) is considerably enhanced by adding a shorting pin and the impedance bandwidth (IBW) is improved by etching pentagon- shaped slot in the defected ground. The antenna offers wide CP impedance bandwidth of 4.96GHz (13.6GHz-18.56GHz)) and simulated ARBW 4.85GHz (14.51-19.30GHz) and positive gain in the Ku-band. The presented antenna is appropriate for Ku-band applications.A novel exact solution algorithm for a robust product portfolio problem under return uncertainty
http://scientiairanica.sharif.edu/article_22366.html
This research address the optimization of product portfolio problem under uncertainty using the principles of financial portfolios theory. Since the success of the product portfolio is a strategic decision and it depends on the return&rsquo;s future changes, the return is best to be considered as an uncertain parameter. The innovation of this research is the use of robust optimization approach and providing an exact solution algorithm based on the model of Bertsimas and Sim. Given the assumption of uncertainty in the returns, the product portfolio model is developed based on the robust counterpart formulation of Bertsimas and Sim. An exact solution algorithm is also presented to reduce the solution time. The results obtained by implementing in a real case study of the dairy industry in Iran show that increasing the confidence level decreases the portfolio&rsquo;s total returns and increases its total risk. A comparison between the proposed algorithm and similar methods shows that, on average, it makes 3% improvement in the solution time.Finite–time synchronization of a new five–dimensional hyper–chaotic system via terminal sliding mode control
http://scientiairanica.sharif.edu/article_22367.html
This paper constructs a new five&ndash;dimensional hyper&ndash;chaotic system with complex dynamic behaviors. It also analyzes the chaotic attractor, bifurcation diagram, equilibrium points, Poincare map, Kaplan&ndash;Yorke dimension and Lyapunov exponent behaviors. We prove that the introduced new hyper-chaotic system has complex and nonlinear behaviors. Next, the work describes fast terminal sliding mode control scheme for the control and synchronization of the new hyper&ndash;chaotic system. Stability analysis is performed using the Lyapunov stability theory. For the synchronization, both master and slave systems are perturbed by different parameter and model uncertainties. Both steps of the sliding mode controller have finite&ndash;time convergence properties. Subsequently, it has been shown that the state paths of both master&ndash;slave systems can reach each other in a finite time. One of the main features of the proposed controller is the finite time stability of the terminal sliding surface designed with high&ndash;order power function of error and derivative of error. Finally, using the MATLAB simulation, the results are confirmed for the new hyper&ndash;chaotic system.An Availability Evaluation Method for Desalination Process with Three-States Equipment under the Specific Repair Queuing Policy
http://scientiairanica.sharif.edu/article_22369.html
Oil waste, is one of the most important pollutants in the oil and gas industry. Since the wells' oil has significant saltwater, the effluent amount increases with increasing oil reservoir extraction. Separating the saltwater from the extracted oil before starting the refinery process plays an essential role in reducing the oil costs as well as the useful transfer capacity. This paper presents a new Chapman-Kolmogorov Equation-based (CKEB) method to evaluate a desalination system's availability with three-state equipment and weighted-k-out-of-n configuration. In this system, the equipment is repairable, and each repair facility can repair all equipment types of different sub-systems (pump stations). We consider all failures and repairs to have a constant rate (with Exponential distribution) and use the Chapman-Kolmogorov Equation to drive the system&rsquo;s availability. Then we validate the presented method using a simulation technique. Finally, the elapsed time of both solving techniques is compared. The results show the superiority of the CKEB technique in terms of computational time. Compared with the simulation technique, the computational time ratio for the CKEB method is between 0.0002% to 0.0058% for the small-size problems, between 0.05% to 0.94% for the medium-size problems, and between 1.31% to 5.39% for the large-size problems.Performance Improvement of a Grid-connected Voltage Source Converter Controlled by Parabolic PWM Current Control Scheme
http://scientiairanica.sharif.edu/article_22370.html
Parabolic carrier PWM method is considered as one of the direct current control methods which has been proposed for the voltage-source converters (VSCs). This method has an excellent dynamic response. Besides, it proposes a constant switching frequency by employing a pair of parabolic PWM carriers. However, it suffers from some drawbacks and limitations. The major drawback of this method is its sensitivity to the inductance variations. In other words, in grid-connected applications the exact value of grid inductance should be exactly known to achieve a proper performance from this method. Moreover, it is essential that during each switching cycle the voltage at the point of common coupling remains constant. In grid connected applications such as active power filter these drawbacks may lead to operate at variable or non-expected frequencies. Therefore, this paper concerns the suggestions to deal with the situation. In this paper, by applying the conventional method the aforementioned problems are examined in a grid-connected active power filter. It is shown analytically that by using the proposed method, problems of sensitivity to inductance changes and also necessity to constant voltage at point of common coupling in a switching period will be solved. Finally, simulation and experimental results are presented.Assessment of Isometric Muscle Exertion in Short-term Considering Task-rest Schedule
http://scientiairanica.sharif.edu/article_22380.html
Numerous workers experience occupational diseases, especially musculoskeletal disorders, due to various physical, psychological, and individual factors. Among known risk factors for musculoskeletal disorders, work-rest patterns, and muscle fatigue are to be named. Assessment of muscle fatigue plays an important role, leading to a proper design for a work-rest program. This study was aimed to investigate isometric muscle strength in Iranian workers during repetitive activities based on gender and rest time. It has been attempted to present a model for isometric muscle strength. In a laboratory experiment, 31 students comprised of 19 males and 12 females participated, and muscle strength was recorded by a dynamometer. Minitab software results analysis proved that females' upper body muscles showed a higher level of resistance to fatigue rather than males. Furthermore, tests' results for each individual were more in line with cubic regression so that four models with a high R-Sq index (at least 94.4%) and high R-Sq (adj) index (at least 77.8%) were presented to predict isometric muscle strength in short-run. Finally, it has been suggested to use male workers for repetitive activities with a high workload and enough rest time and use female workers for repetitive activities with low workload and high frequency.Investigation of Experimental and Statistical (Respond Surface Method and Grey Relational Analysis) of Surface Roughness, Vibration and Enerrgy consumption Values of Titanium Alloy During Machining
http://scientiairanica.sharif.edu/article_22385.html
This study aims to explain the interaction between the results measured in the turning operation. For this purpose, Ti 6Al-4V alloy workpiece was machined on CNC lathe. Surface roughness (Ra), vibration and energy consumption values were determined by turning. Experimental results were analyzed statistically. Response surface method (RSM) and grey relational analysis were used statistical analysis. In RSM analysis, regression equations, ANOVA, contour graphs, pertubation graphs, real and prediction graphs, % contribution graphs, most significant factor, optimum parameters, it is determined that the effective parameter in surface roughness, vibration and energy consumption is feed rate. Grey relational analysis steps and results are examined.Modelling and Optimization of Robotic Manipulator Mechanism for Computed Tomography Guided Medical Procedure
http://scientiairanica.sharif.edu/article_22387.html
Although industrial robots are common, a higher degree of manipulability might be required to expand the applications of manipulators in the field of medicine. Modifying the mechanical design of a robot as per the workspace can be perceived as an optimization problem. Hence, a novel spatial manipulator is designed for a diagnostic apparatus using different optimization algorithms. Standard Genetic Algorithm (SGA) and GA (Genetic Algorithm) with hybrid functions like pattern search (PS) and fmincon are proposed to optimize the link lengths of a 3degrees of freedom (DOF), 6-DOF, and novel 9-DOF hybrid redundant manipulator. A 9-DOF robot is designed to manipulate a needle in CT machine environment. The fitness function for all the manipulators is formulated using forward kinematic equations according to their workspace. Limits and constraints of each link are decided beforehand. A comparative study between all the hybrid GA functions is performed. MATLAB is used to solve and train the proposed GA method for optimizing the link lengths. Results show that GA with PS provide better-optimized link lengths for a 3-DOF and 9-DOF manipulator while fmincon is well suited for a 6-DOF robot manipulator. Workspace and dead zone analysis is also performed using the optimized link lengths obtained.Proximity effects between two plus-plan shaped high-rise buildings on mean and RMS pressure coefficients
http://scientiairanica.sharif.edu/article_22389.html
Wind-induced interference effects may result in a significant increase or decrease in the wind loads on the buildings constructed in groups due to modifying wind flow around, depending on the shape and relative location of the buildings. Experimental study of wind-induced interference effects on mean and root mean square (RMS) pressure coefficients between two tall buildings are investigated in detail for various interference conditions in this study. The Interference effects on mean and RMS pressure coefficients are presented as interference factors i.e. mean interference factor (MIF) and RMS interference factor (RIF). Results show that the interference effects on local wind pressure are significantly higher on the windward side's faces near the recessed corner. The full blockage condition generates suction on walls facing the gap. The half blockage and no blockage conditions create a more severe interference effect than the full blockage. The maximum value of MIF is 4, 9 and 13 in full, half and no blockage condition, respectively. Interference effects result in reduced wind load on side faces and faces at the leeward side. Suction at side faces reduced approximately by 65% in full blockage condition. RIF&rsquo;s values less than unity are observed for all interference cases.Short-term prediction of traffic state, statistical approach versus machine learning approach
http://scientiairanica.sharif.edu/article_22391.html
Traffic short-term prediction helps intelligent transportation systems manage future travel demand. The objective of this paper is to predict the traffic state for Karaj to Chaloos, a suburban road in Iran. For this, two approaches, statistical and machine learning are investigated. We evaluate the performance of the multinomial logit model, the support vector machine, and the deep neural network as two machine learning techniques. The principal component analysis is used to reduce the dimension of the data in order to use the MNL model. SVM and DNN predict traffic state using both primary and reduced datasets (ALL and PCA). MNL can be used not only to compare the accuracy of models but also to estimate their explanatory power. SVM employing primarily datasets outperforms other models by 79% accuracy. Next, the prediction accuracy for SVM-PCA, MNL, DNN-PCA, and DNN-ALL are equal to 78%, 73%, 68%, and 67%. SVM-ALL has better performance for predicting light, heavy, and blockage states, while the semi-heavy state is predicted more accurately by MNL. Using the PCA dataset increases the accuracy of DNN but decreases SVM accuracy by 1%. More precision is achieved for the first three months of testing compared to the second three months.Simulation The Force- Displacement Behavior of Reinforced Concrete Beams Under Different Degrees and Locations of Corrosion
http://scientiairanica.sharif.edu/article_22392.html
Regarding the failures due to corrosion in later years, concern about corrosion damage has been intensified and some tests have been carried out in order to study the effect of corrosion on capability of bending and shear capacity of reinforced concrete beams. For as much as these studies is experimental commonly and using from its results subject to spend time and financial costs, this study is set to analyze behavior of corrosion found reinforced beams, using ABAQUS computer software. For this purpose, the sound reinforced concrete beams is modeled, first and simulating accuracy is confirmed by existing experiment results. Then corrosion found beams with different degrees are modeled by ABAQUS software and their results were compared with experimental results and finally, P-∆ charts are produced and provided for software models. In the way of simulations, effects of corrosion site, amount and intensity of corrosion, concrete compressive strength and bar yielding stress on behavior of reinforced concrete beams under corrosion is examined. In this investigation, the effect of different locations and different corrosion degrees is considered regarding changes which take place in cross section of steel, mechanical characteristics concrete and steel and integrity between steel and concrete.A two-stage stochastic supply chain scheduling problem with production in cellular manufacturing environment: A case study
http://scientiairanica.sharif.edu/article_22394.html
An integrated decision in supply chain is a significant principle in order to compete in today&rsquo;s market. This paper proposes a novel mathematical model in a two-stage supply chain scheduling to cooperate procurement and manufacturing activities. The supply chain scheduling along with the production approach of cellular manufacturing under demand, processing time, and transportation time uncertainties makes business environment sustainably responsive to the changing needs of customers. Uncertainties are formulated by queuing theory. In this paper, a new mixed-integer nonlinear programming formulation is used to determine types of vehicles to carry raw materials, suppliers to procure, priority of each part in order to process, and cell formation to configure work centers. The goal is to minimize total tardiness. A linearization method is used to ease tractability of the model. A genetic algorithm is developed due to the NP-hard nature of the problem. The parameters of the genetic algorithm are set and estimated by Taguchi&rsquo;s experimental design. Numerous test problems are employed to validate the effectiveness of the modeling and the efficiency of solution approaches. Finally, a real case study and a sensitivity analysis are discussed to provide significant managerial insights and assess the applicability of the proposed model.Metaheuristic approach proposal for the solution of the bi-objective course scheduling problem
http://scientiairanica.sharif.edu/article_22395.html
Timetabling problems are among the commonly encountered problems in real life, from education institutions to airline companies. It is generally difficult to obtain optimal solutions for the timetabling problems that vary in terms of structures of constraints and objective functions, and these problems are considered being in NP-hard category, which cannot be solved in polynomial time in real life. In this study, a bi-objective mathematical model is proposed for a course scheduling problem in Kutahya Dumlupinar University Department of Industrial Engineering. While it is aimed in the first objective function to maximize the sum of the preferences of instructors determined by using the Analytic Hierarchy Process Method, it is aimed to minimize the students&rsquo; course overlap in the other. Conic scalarization method is used to combine the objective functions. Due to NP-hard nature of the problem, the Tabu Search Algorithm, one of metaheuristic approaches is used to solve it. Using the obtained data, the Tabu Search Algorithm by considering the proposed bi-objective mathematical model is designed for the problem and a software is developed in Excel Visual Basic program. The experimental results are evaluated with Analysis of Variance by using Minitab Program, comparing the results, satisfactory solutions are obtained.Risk Governance Mechanism of Food Safety Based on Product Reputation
http://scientiairanica.sharif.edu/article_22396.html
Food matters public daily lives, it is both practically and theoretically imperative to enhance the governance of food safety risks. In this paper, a three-tier supply chain model involving government regulatory authorities, food producers and customers is established for designing a risk governance mechanism of food safety based on a reputation updating model. Meanwhile, the study also explores the influence of reputation on product quality and sales price for food producers, as well as the accuracy in testing product quality of government and the effectiveness of governmental regulations. The results show that product price is positively correlated with the reputation, and negatively related the government's rewards and punishments. When the government improves accuracy of food sample testing and enhances rewards and strengthens punishments for food producers, product quality can be effectively controlled, sales prices can be balanced, and producer&rsquo;s profits can be improved. Finally, this paper provides insight on the risk governance of food safety through many observations. It is found that a relatively slow process for producers to improve company reputation by improving its product quality, but issues with food quality and safety afford a devastating blow to the company reputation once this information is released.Optimization of Facility Location-Allocation Model for Base Tranceiver Station Antenna Establishment Based on Genetic Al-gorithm Considering Network Effectiveness Criteria (Case Study North of Kermanshah)
http://scientiairanica.sharif.edu/article_22397.html
It is clear that the location of the BTS antennas plays a very important role in the proper service and coverage of the mobile connection. Proper location of these antennas is a major challenge for operators in each country, as in addition to maximum network coverage, service costs must also be acceptable and competitive. This means that in busy areas, in order to provide better service, the number of antennas must be greater and closer to each other. In general, the location problem is a type of optimization problem that aims to select a subset of the set of candidate locations to create the facilities that provide the best service at the lowest cost. To solve such problems in a reasonable time, we can use meta-heuristic algorithms to find solutions that are very close to the optimal solution. Accordingly, this paper attempts to apply the genetic algorithm to find a suitable solution for finding BTS mobile antennas in north Kermanshah. A GA model is proposed that improves the location coordinates of the current BTS antennas extracted from the GIS system. Comparison of model results with the status of BTS active antennas in Kermanshah shows the performance of the model.Robust Bi-Objective Operating Rooms Scheduling Problem Regarding the Shared Resources
http://scientiairanica.sharif.edu/article_22398.html
In recent years, many efforts have been made to provide different strategies for enhancing the scheduling and planning of the operating rooms. The efficient planning and scheduling of ORs is a complex task since it has to account for the availability of human resources, medical equipment, and medication required for each surgery but that are often shared between different ORs. This paper proposes a mathematical approach to enhance the management of OR resources. It presents a bi-objective robust optimization approach for scheduling the surgeries in the ORs and recovery room, regarding the uncertainty of the surgery time, uncertainty of hospitalization time in the recovery room, and shared resources. The first objective function aims to minimize the maximum completion time of the surgeries and the second one minimizes the sum of the earliness-tardiness of the surgical operations. The suggested approach utilizes the multi-choice goal programming approach with utility function to solve the proposed model. The proposed approach is applied to a real case in the Shahid Beheshti hospital, Babol, Iran. The obtained results show that the suggested bi-objective robust optimization approach can enhance OR scheduling and should be designed into a decision support system for OR management.Single and Multi-Stage Manufacturing Systems Under Imperfect Quality Items with Random Defective Rate, Rework and Scrap
http://scientiairanica.sharif.edu/article_22399.html
Abstract. The classical manufacturing systems assume that all of produced items are of perfect quality. They also does not consider rework process in manufacturing operations. Moreover, most of previous literature consider single stage production-inventory systems and do not consider multi stage options. However, in real world production-inventory systems, production of defective items is inevitable, and a fraction of produced items may be defective. In addition, to avoid extra costs and consider environmental issues, organizations tend to reworking activities. We propose single and multi stages production-inventory systems in manufacturing operations where the process is defective, rework is possible and a percent of items are scrapped. A main assumption, in current paper, is that the defective rate is assumed to be uncertain parameter. The grey systems theory, as a mathematical tool to address the uncertain information in real-world situations, is utilized to model the random defective rate via a grey nonlinear programming problem. The proposed issues are investigated via numerical examples to assess the impact of grey parameters on optimal solutions.An equity-oriented multi-objective inventory management model for blood banks considering the patient condition: A real-life case
http://scientiairanica.sharif.edu/article_22400.html
The absence of systematic disparities in health utilization leads to achieving equity in health. However, equity in delivering healthcare services is always challenging because of financial and medical resource constraints. In this regard, a practical multi-objective mixed-integer linear programming model with priority-differentiated demand classes is presented for cost-effective inventory management of blood products considering health equity. The system deals with multiple substitutable products. There are elective and non-elective demands, which are categorized into three main classes based on medical urgencies. The health objectives are investigated to achieve a desirable health equity level in delivering healthcare services to patients. Moreover, the economic objective is pursued to minimize total costs incurred across managing the inventory without weakening the service level. An effective demand-oriented hybrid heuristic is proposed to issue and allocate the blood for demand satisfaction equitably. A goal programming approach is utilized to find the optimum solution. The applicability of the model is validated through a real case study. Finally, several sensitivity analyses are conducted to gain useful managerial insights. According to the results, the proposed model presents a proper solution by making a reasonable health-economic trade-off. Also, the results illustrate the beneficial improvement in patient care and promoting health equity.An improved MULTIMOORA method for multi-valued neutrosophic multi-criteria group decision-making based on prospect theory
http://scientiairanica.sharif.edu/article_22401.html
With the development of the economy and society, the scale of cities is increasing. At the same time, there are many subways being constructed in many cities. In the construction of subways, an appropriate scheme plays an important role in reducing cost and improving the satisfaction of the public. This paper attaches great importance to present a multi-criteria group decision-making (MCGDM) method to deal with selecting an appropriate construction scheme for subways. The process of selecting an appropriate construction scheme for subways is complex because it includes a great deal of fuzzy and uncertain information which can be presented by multi-valued neutrosophic numbers (MVNNs). In addition, in order to handle the interaction of inputs, an improved generalized multi-valued neutrosophic weighted Heronian mean (IGMVNWHM) operator is introduced. Subsequently, a new distance measure between two MVNNs is defined for deriving the objective criteria weights. Furthermore, considering the bounded rationality of decision-makers, we develop an improved multi-valued neutrosophic MULTIMOORA method based on prospect theory (IMVN-PT-MULTIMOORA). Finally, an application example of selecting an appropriate construction scheme for a subway and the influence of parameter are described. In addition, the proposed approach is compared with some existing methods to prove its validity and advantages.L-Moments and calibration based variance estimators under double stratified random sampling scheme: an application of covid-19 pandemic
http://scientiairanica.sharif.edu/article_22402.html
The presence of extreme events gives rise to outrageous results regarding population parameters and their estimates using traditional moments. Traditional moments are usually influenced by extreme observations. In this paper, we propose some new calibration estimators under L-Moments scheme for variance which is one of the most important population parameters. Some suitable calibration constraints under double stratified random sampling are also defined for these estimators. Our proposed estimators based on L-Moments are relatively more robust in presence of extreme values. The empirical efficiency of proposed estimators is also calculated through simulation. Covid-19 pandemic data from January 22, 2020, to August 23, 2020, is considered for simulation study.Continuous fixed-time nonsingular terminal sliding mode control of second-order nonlinear systems with matched and mismatched disturbances
http://scientiairanica.sharif.edu/article_22403.html
This paper investigates fixed-time nonsingular terminal sliding mode control of second-order nonlinear systems in the presence of matched and mismatched disturbances. Using estimation of the mismatched disturbance estimated by a fixed-time disturbance observer, a novel nonlinear dynamic sliding surface is designed. This estimation is utilized in designing a completely novel nonlinear dynamics sliding surface whereby the fixed-time convergence of the sliding motion is guaranteed in spite of mismatched disturbance. The convergence time of the closed-loop system including disturbance observer and control system is guaranteed to be uniform with respect to initial conditions. Moreover, the proposed controller avoids chattering phenomenon by producing a continuous control signal.Placement of Electric Vehicle Charging Station and Solar DG in Distribution System considering Uncertainties
http://scientiairanica.sharif.edu/article_22404.html
Electric vehicle penetration in the transport section is increasing and replacing the conventional fossil fuel based vehicles. Still, EV has not received success due to some limitations such as cost of the vehicle, battery capacity and availability of charging station. The availability of charging station depends on its geographical location. At the same time, location in the electrical network affects the energy loss and voltage deviation. Therefore, a road network of urban area overlapped with a 33-bus distribution network has been taken as test system for this work. Allocation of EV charging stations and photovoltaic energy resources as renewable distributed generation have been attempted simultaneously using 2-layer optimization. Differential Evolution and Harris Hawks Optimization techniques have been employed to solve the problem and the final results have been validated using eight other established optimization techniques. 2m point estimation method has been used to take care of uncertainties related to electric vehicles and PV. Monte-carlo simulation is also applied to cross verify the performance. The land cost, customer accessibility to charging station have been taken into account to allocate it at proper places. The whole work has been performed based on the 24-hrs dynamically varying electric vehicles flow and PV outputs.A Three-Stage Optimization Model for Scheduling the Facilities Maintenance Considering Random Failure Rate
http://scientiairanica.sharif.edu/article_22405.html
The increasing value of facilities, on the one hand, and the complexity of the equipment used in them, on the other, have increased the importance of planning for the maintenance of facilities, especially for companies which their facilities are located in different locations. In this paper, a new hybrid model has been presented to optimize facility maintenance scheduling by a combination of Genetic Algorithms (GA), Particle Swarm Optimization (PSO) and the Monte Carlo Simulation for organizing facilities which are in different locations as well as determining the optimum number of crews with three different skills of mechanical, electrical and simple workers. The main contributions of this paper include: (a) optimizing the number of crew by different skills in the first stage. (b) evaluation of fitness value for each solution through the Monte Carlo Simulation Model. (c) scheduling by consideration different failure rates for different facilities in different locations. In order to evaluate the performance of the proposed model, the model has been compared with Golpira&rsquo;s model, the results of which have shown that it is possible to reduce the cost by just over 39% and reduce MTBF by over half.Dynamics and circuit simulation of a fractional-order hyperchaotic system
http://scientiairanica.sharif.edu/article_22412.html
A hyperchaotic system with fractional terms and fractional-order derivatives is investigated in this paper. Simulations show that different attractors such as equilibrium point, limit cycle and hyperchaotic attractor can be generated by the system. Circuit of fractional-order integrator is designed and it is used to implement the circuit of the studied system. The circuit implementation of the studied system proofs its feasibility. A hyperchaotic system with fractional terms and fractional-order derivatives is investigated in this paper. Simulations show that different attractors such as equilibrium point, limit cycle and hyperchaotic attractor can be generated by the system. Circuit of fractional-order integrator is designed and it is used to implement the circuit of the studied system. The circuit implementation of the studied system proofs its feasibility.An Equation to Estimate Maximum Normal Strain of Buried Steel Pipes at Bend Area Under Propagating Waves in Sands
http://scientiairanica.sharif.edu/article_22414.html
The possible vulnerability of pipelines under propagating waves especially at bend area emphasizes the need of studying in this context. In the presented studies in this field the beam and beam-shell hybrid models were usually used but in this study a continuum model is examined. For this purpose, the bent pipe is modeled by shell elements and suitable boundary conditions are considered to simulate the infinite length of the pipe away from the bend. The soil around the pipe is modeled by 3D elements obeying the Mohr-Coulomb rule of behavior. Also, equivalent boundary conditions are used at the boundaries of the soil domain where it is truncated. By varying the properties of the pipe-soil model, it is investigated under seven different ground motions and the maximum axial strain is calculated at the bend area. Effects of different parameters including incidence angle of seismic waves, bend angle, pipe diameter to wall thickness ratio, and physical properties of soil are investigated. Using the results of analysis and regression, an equation is proposed for estimating the maximum normal strain of buried pipes at the bend area with good accuracy.Symbiotic organisms search based multi-objective optimal placement of distributed generators considering uncertainty of source and load
http://scientiairanica.sharif.edu/article_22415.html
Integration of Distributed Generation (DG) in the Distribution network will reduce the network expansion costs and increase the network reliability in terms of reduction in voltage magnitude deviations.This paper presents Symbiotic Organisms Search (SOS) based technique for finding out the best size and position of DG in Radial Distribution networks to improve the voltage profile and voltage security state of the Distribution network. The primary objectives of the paper are minimization of bus voltage variation and maximization of voltage stability index of the network as a multi objective optimization problem in presence of uncertainty of sources and loads. In this paper the uncertainty of solar power, wind power and load are modelled using 2m Point Estimate Method along with SOS algorithm.To show the effect of DG placement on voltage security state of Distribution system, the system is classified into three states based on the values of voltage stability index (VSI). Simulation results as obtained from two standard (IEEE) radial distribution networks prove the efficiency and accuracy of the proposed SOS method. The results of SOS based method are compared with some other techniques as found in recent literature, which shows that SOS algorithm outperforms other standard optimization techniques.Design of an Efficient Vehicle-Actuated Signal Control Logic for Signalized Intersections
http://scientiairanica.sharif.edu/article_22418.html
The effectiveness of fixed-time management systems dramatically decreases in case of fluctuated traffic demands at signalized intersection approaches. This leads to the waste of time in traffic and may cause material, psychological and ecological problems. Especially in recent years, to minimize the negative impacts of these problems, many researchers focus on Intelligent Transportation Systems (ITS). As it is known, one of the Intelligent Transportation Systems applications is called vehicle-actuated (traffic-actuated) management systems. Because the success of these types of applications is directly related to the created control logic, the selection of the most proper control parameters for the created control logic is an important issue. This study aims to create an effective control logic and flow chart for the vehicle-actuated management system. At the end of the analyses, it is seen that the created vehicle-actuated management system can adapt to fluctuations in traffic demands at signalized intersection approaches. Average vehicle delays, fuel consumptions and exhaust emissions can be reduced significantly by the created system. Especially, in case of fluctuations in traffic demands at intersection approaches exist, it is concluded that the performance of the intersection can increase enormously with the created vehicle-actuated management system.A Generalized Finite Element Approach towards the Free Vibration Analysis of Non-uniform Axially Functionally Graded Beam
http://scientiairanica.sharif.edu/article_22419.html
A generalized finite element approach, for the free vibration analysis of an axially functionally graded (AFG) beam, having non-uniform thickness, has been presented in the current analysis. The use of non-uniform beam element and the way of assembling the same, make the finite element model, a generalized one. The current approach can be used for beams of both uniform and non-uniform thickness, with any of the homogenous and inhomogeneous material variation. The governing equation for free vibration of beam has been derived considering Euler-Bernoulli beam theory and by using Euler-Lagrange's equation. The cross-section of the of the beam is decreasing along the length depending upon the exponential function considered for variation in thickness. The material inhomogeneity is as per the Power and Exponential law of material variation along the axial direction, taken from the literature. Mathematical modelling of geometric non-uniformity, material inhomogeneity and finite element analysis of the AFG beam, have been performed using MATLAB. The effect of geometric non-uniformity and material gradient parameters on the fundamental frequencies of vibration in different classical boundary conditions have been investigated. The efficacy of the current method has been ascertained by comparing the result of available literature.Multi-depot home health care routing and scheduling problem with multimodal transportation: Mathematical model and solution methods
http://scientiairanica.sharif.edu/article_22420.html
Abstract Providing appropriate home health care is one of the increasing concerns in the health care organizations. Home Health Care provides various services for disabled or elderly individuals at their homes. Also, deal with the current critical situation of the coronavirus disease (COVID-19) due to the limited capacity of hospitals and the feeling of insecurity in crowded places, home health care is more recommended. This paper addresses a Home Health Care Routing and Scheduling Problem (HHCRSP) with two modes of transportations including public and private modes. Also, multi-depot version of the problem is studied to enhance the service delivery in scattered points. In this study, a mathematical model is presented based on a Mixed Integer Linear Programming (MILP) whose objective function is minimization of the sum of the travel distance and overtime costs. Furthermore, three meta-heuristic algorithms including Invasive Weed Optimization (IWO), Grasshopper Optimization Algorithm (GOA) and Simulated Annealing (SA) are presented for solving the large-sized problems. Since the performance of meta-heuristic algorithms depends on setting the parameters, Taguchi method is used to statistically set parameters of the developed algorithms. The computational results have shown that the proposed IWO has worked better than the other two proposed algorithms statistically.Joint production-planning and distribution optimization of perishable products under a combined shipment structure: A new hybrid policy-based approach
http://scientiairanica.sharif.edu/article_22421.html
Following the need for joint optimization of decisions in supply chains, this paper newly provides an integrated framework to efficiently fulfill a production-planning-routing problem (PPRP). In such integrated scheme, a set of perishable family-products are manufactured on a single batch-processing machine. These products are dispatched to the customers by a third-party logistics service provider with only two types of licensed eco-friendly transportation facilities. In order to efficiently deliver the manufactured products before they become unusable, we propose a combined shipment structure. To accomplish this, we formulate the problem in the context of a MILP model. In particular, we aim to establish two manufacturing policies based on both increasing and decreasing rates of production and also two delivery policies expressing distinct preferences in fulfilling the customers&rsquo; demands. In this regards, we investigate the cost structures obtained from the established integrated planning and the resulting distribution configurations as well. Further, four heuristic algorithms are developed for solving the problem with respect to each hybrid production/distribution scheme derived from the former policies. Finally, to compare the mentioned procedures, it is conducted a numerical study illustrating the preferable efficiency of the plan gained according to the hybrid of the increasing-production-rate and decreasing-delivery-distance policies.Detection of the Stator Inter-Turn Fault Using the Energy Feature of the Wavelet Coefficients Obtained by Continuous Wavelet Transform
http://scientiairanica.sharif.edu/article_22422.html
This research aims to investigate a fault detection method applicable to the stator part of the Brush-Less DC motor (BLDC). Indeed, it is a concern to make sure the motor is operating in a healthy mode, and in any other case, it is of great importance to detect the fault as soon as possible to prevent the further ruin of the major system. Regarding this, a sub-branch method of the Wavelet Transform (WT) analysis, named Continuous Wavelet Transform (CWT), is utilized to observe the short-circuit fault in the stator coils. Thus, a novel simulator of the BLDC motor is developed by making an interconnection between ADAMS and MATLAB in which different electrical and mechanical components are included. Therefore, a close-to-reality model of the BLDC motor is achieved, leading to a more accurate evaluation of the proposed method. An energy-type feature will be suggested to characterize the fault happening. Through acquiring the normalized energy amount for one of the Wavelet Coefficient (WC) signals, obtained by the CWT, and comparing the energy with a predefined threshold amount of energy for that signal, it is feasible to detect the stator's flawed performance. By conducting different simulations, the proposed method will be validated.Evaluating the Nature of Captured Exhaust Soot from a Retort Heating Carbonisation System
http://scientiairanica.sharif.edu/article_22423.html
Deeper understanding of all aspect of biomass thermochemical conversion is necessary as researchers pursue multiple avenues for energy and environmental sustainability. In this paper, the agglomerative accumulation of soot observed, captured on the inner surface of the exhaust pipe, during the operation of a top-lit updraft biomass gasification system was evaluated to understand its nature and qualities. The soot was evaluated using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy with Energy Dispersion Spectroscopy (SEM-EDS) and Brunauer&ndash;Emmett&ndash;Teller (BET) analyses. The combustion fuels were bamboo (Bambusa vulgaris) stalk and stem of African balsam (Daniellia olivieri). FTIR analysis revealed the presence of hydroxyl, aromatic double bond, aldehyde, thyiol and carbonyl functional groups. EDS analysis revealed that the elemental carbon content of the soot was found to be 75.05% carbon with 15.13% oxygen. SEM analysis revealed that the soot has a hollow morphology and a lustrous appearance with white tiny grit grains of carbon nano-spheres. The BET analysis revealed that the specific surface area of the soot was 500 m2/g while the pore volume and pore diameter were measured to be 0.218 cc/g and 2.113 nm respectively. The material can find use in water purification purposes, and as an additive in lubricating oilsIntelligent Algorithm based Efficient Planning of Electric Vehicle Charging Station: A Case Study of Metropolitan City of India
http://scientiairanica.sharif.edu/article_22425.html
Electric vehicles are gaining popularity and going to become the mainstream mode of transportation in urban and rural areas not only in India but globally in the next few years. In the adoption of electric vehicles, there are certain issues like proper charging infrastructure, charging time etc. and out of these the sizing and siting of the charging station particularly in urban areas where the cost of land and location plays an important role. Thus, it is important that the charging station location should be easily accessible for the electric vehicle users and cost effective as well. This paper presents an intelligent algorithm based efficient planning of electric vehicle charging station considering geographical information and road network. The cost function has considered such as investment cost, charging station electrification cost, electric vehicle energy loss cost and travel time cost. An intelligent algorithm-based approach is employed to solve the planning problem of electric vehicle charging stations. Further, the impact on reliability of the grid is also evaluated by determining the charging cost loss on each considered location. The result shows that the applied method provides better optimized solutions which are beneficial for electric vehicles users, charging station operator and utility grid.An integrated model for optimal selection of quality, maintenance, and production parameters with auto correlated data
http://scientiairanica.sharif.edu/article_22426.html
Statistical process monitoring, maintenance policy, and production have commonly been studied separately in the literature, whereas their integration can lead to more favorable conditions for the entire production system. Among all studies on integrated models, the underlying process is assumed to generate independent data. However, there are practical examples in which this assumption is violated because of the extraction of correlation patterns. Autocorrelation causes numerous false alarms when the process is in the in-control state or makes the traditional control charts react slowly to the detection of an out-of-control state. The auto-regressive moving average (ARMA) control chart is selected as an effective tool for monitoring autocorrelated data. Therefore, an integrated model subject to some constraints is proposed to determine the optimal decision variables of the ARMA control chart, economic production quantity, and maintenance policy in the presence of autocorrelated data. Due to the complexity of the model, a particle swarm optimization (PSO) algorithm is applied to search for optimal decision variables. An industrial example and some comparisons are provided for more investigations. Moreover, sensitivity analysis is carried out to study the effects of model parameters on the solution of the economic-statistical design.Uncertain model of industrial clusters for the optimal arrangement of co-operation networks under sustainable and dynamic conditions
http://scientiairanica.sharif.edu/article_22427.html
Industrial clusters are one of the most current development models. Aggregation of firms in a geographical area has many advantages, such as cost reduction, better supply, and knowledge emission with linkage together. The linkage result will be created the networks. The industrial clusters without co-operation networking will not be developed. That must be noticed to severe changes of business environment parameters. Therefore, this paper develops an uncertain mathematical model under sustainable and dynamic conditions. The model contains four objectives, namely profit, transportation cost, employment, and environment appraisal of the cluster. The outcome of this research is to find the best/optimal solution for firms&rsquo; arrangements with/within networks that maximize the profit, employment, and environment score and so minimize the transportation cost. The assignment patterns show horizontal and vertical cooperation with/within networks. The efficiency of model clustering in sub-clusters is followed by the neighbor clustering efficiency and the one&rsquo;s clustering efficiency methods.Decompositions of soft sets and soft matrices with applications in group decision making
http://scientiairanica.sharif.edu/article_22428.html
The decompositions of soft sets and soft matrices are important tools for theoretical and practical studies. In this paper, firstly, we study the decomposition of soft sets in detail. Later, we introduce the concepts of $\alpha$-upper, $\alpha$-lower, $\alpha$-intersection and $\alpha$-union for soft matrices and present some decomposition theorems. Some of these operations are set-restricted types of existing operations of soft sets/matrices, others are $\alpha$-oriented operations that provide functionality in some cases. Moreover, some relations of decompositions of soft sets and soft matrices are investigated and the newfound relations are supported with numerical examples. Finally, two new group decision making algorithms based on soft sets/matrices are constructed, and then their efficiency and practicality are demonstrated by dealing with real life problems and comparison analysis. By using these proposed approaches, solutions can be presented to soft set-based multi-criteria decision making problems, both ordinary and involving primary assessments. These allow to handle soft set-based multi-criteria decision making from different perspectives.A new mathematical formulation and a hybrid evolutionary algorithm for re-entrant flow-shop problem with release date
http://scientiairanica.sharif.edu/article_22430.html
In this paper, we address the weighted multi-objective re-entrant flow-shop scheduling problem considering release dates in order to minimize makespan, total completion time, total tardiness, maximum idle time, and number of tardy jobs. Each job is taken into account with deterministic processing times, and release dates. The flow-shop comprised of two workshops in whose jobs are entered to the main workshop and after the first part of the processing, they are transferred to the second workshop and after this stage, the jobs are returned to the main workshop for the last part of the processing. We model the problem by a new mixed integer programming based on formulating sum of idle time as a new concept. Moreover, a hybrid evolutionary algorithm is proposed based on some dispatching rules, ant colony optimization, and genetic algorithm. The performance of the proposed algorithm on some test instances is compared to the mixed integer linear programming model as well as the state-of-the-art algorithms called genetic algorithm, tabu search, bio-geography based optimization, and artificial bee colony. The computational experiments show that our proposed approach outperforms other algorithms and the results indicate efficiency and capability of the proposed algorithm in comparison with the traditional algorithms.Using Grey Wolf Optimizer to Minimize Voltage Total Harmonic Distortion of a Salient-Pole Synchronous Generator
http://scientiairanica.sharif.edu/article_22431.html
It is important to calculate the optimum design parameters of synchronous generator (SG) to obtain the desired total harmonic distortion (THD). In this study, we aim to determine the optimum rotor design parameters of SG by using grey wolf optimizer (GWO) algorithm. For this purpose regression modelling is performed to mathematically modelling the relationship between the selected rotor design parameters (factors namely slot pitch, center slot pitch, and damper width) and THD (response). This factor combination is not previously investigated in the related literature. Then by using GWO the optimization is performed on this regression equation. Maxwell simulations have been used for numerical experiments. The results of GWO are compared with the results of genetic algorithm (GA). The results indicate that the GWO algorithm can be well adapted to similar optimization processes and can be effectively used. As a result, the voltage THD of the SG is reduced to 0.3951 under the acceptable magnetic flux conditions. This GWO aided optimization study is significant in that it demonstrates how the performance of SG can be improved by making minor changes to the production line that has been adjusted for mass production without changing the outer diameter and dimensions of SG.Mechanical Safety Analysis of the Gas Lift Completion String Used for a High-Pressure Sandwich Layer
http://scientiairanica.sharif.edu/article_22432.html
This study examines the mechanical safety of a gas lift completion string in a certain oilfield, Algeria 438B block, having complex geological characteristics (a high salt and high-pressure sandwich). When an annulus is not supported within fluid column after unloading using conventional single-tube gas lift completion with positive lift oil production, inner pressure is so low that the pressure differential between the annulus and external casing is very large, which may damage the casing. Hence, a dual tube completion annulus filled with fluid that can resist pressure was used to overcome this problem, in the adjacent blocks using a gas lift production string with positive and reverse lift oil. However, this technology is complex and characterized by poor system reliability, large construction costs and maintenance difficulty. Considering the three aspects of a casing string, the squeeze strength, tensile strength and internal pressure strength, a gas lift completion string with dual concentric tubes and positive lift was preferably selected under conditions that have been verified as safe for production and a shut-in state. It was shown that this gas lift completion string design is feasible.A Stochastic Mathematical Programming Approach to Resilient Supplier Selection and Order Allocation Problem: A Case Study in Iran Khodro Supply Chain
http://scientiairanica.sharif.edu/article_22437.html
Suppliers as one of the main sources of vulnerability may lead to disruption and risk in supply chains. Thus, resilient supplier selection can lead to an increase in the resilience of the supply process, especially in automotive supply chains. The goal of this study is to select a set of resilient suppliers and optimal demand allocation in an automotive supply chain under risk. For this purpose, a bi-objective two-stage stochastic programming model is presented. In contrast to previous mathematical models, our model includes a new objective function to consider the supplier&rsquo;s delivery performance as one of the criteria of resilient supplier selection and also the k-means clustering method is used to cluster and decrease the number of disruption scenarios. In the proposed model, due to the uncertainty of demand, chance-constrained programming approach has been utilized. The augmented Ɛ-constraint method is implemented to solve the presented model. Finally, sensitivity analysis has been done to determine the effect of parameter changes on the final results. The results of the research indicate that contingency planning can reduce the effect of disruption risks. The findings also show that the strategy of the supply chain regionalization is important in reducing the effects of environmental disruption.Attitude Control of a Spacecraft during an Orbital Maneuver for Fast Rejecting of the Large Disturbance Torque without Using the Reaction Control System
http://scientiairanica.sharif.edu/article_22438.html
During an impulsive orbital maneuver, thrust vector misalignment from the center of mass (C.M) generates a large exogenous disturbance torque that results in attitude deviation. This paper aims not to use the reaction control system (RCS) for the spacecraft attitude control. In order to reject the large disturbance very fast, a new control system is proposed. In this method, the large disturbance torque is rejected quickly while the RCS is not employed. The control system is based on one degree of freedom (1DoF) gimbaled-thruster, spin-stabilization, and two control moment gyros (CMG). The nonlinear two-body dynamics of the mentioned spacecraft is formulated. Because RCS is not used, this method is an efficient and implementable method for attitude control of small spacecraft. Numerical simulation shows that thrust vector deviation converges to zero despite disturbance torques. By this method, the disturbance is rejected very fast; thus an accurate orbital velocity change can be obtained. This method can eliminate the initial attitude deviation easily in addition to disturbance rejection. The results show the good performance and superiority of the proposed method compared to some other thrusting maneuver methods.Risk-Based Optimal Decision-Making by the Retailer in A Mixed Local and Wholesale Market Environment Considering Demand Response Solution
http://scientiairanica.sharif.edu/article_22440.html
This paper proposes a comprehensive model to determine the retailer strategy for purchasing electrical power from the wholesale and/or local market in an active distribution network. The uncertainties associated with the load and distributed generation resources in the active distribution network, the wholesale market price and the behavior of the local market players, are all considered in the presented model. A retailer in the demand response program is employed as retailers&rsquo; ability to govern the risks. A risk-based decision-making scheme is provided in this paper which takes into account every instrument that is accessible for retailers along with their associated uncertainties. The major target of this paper is to maximize the retailer benefit concerning a tolerable risk. In order to model risks, the scenario theories are exploited and for solving the optimization problem, particle swarm optimization (PSO) has been utilized. The proposed scheme has been simulated on an actual network and the obtained results confirm the effectiveness and computability of this method.Separation of the Fetal Heart Signal in a Synchronous Network Consisting of the maternal and fetus's heart
http://scientiairanica.sharif.edu/article_22442.html
This paper studies the heart's oscillation model to separate fetal and maternal ECGs from abdominal recordings. To this aim, two phases are designed. A Modified version of the Duffing-Van der Pol oscillator is considered a computational heart model in the modeling phase. To evaluate the interaction effects of the maternal and fetal heart and the differences and features of the fetal heart structure, the fetal heart model is Modified based on the maternal heart model. A non-identical network is employed as an interactive network of the mother and the fetus's heart. Then the degree of the network synchronization is measured with the help of a pattern synchronization index of the non-identical network. An attempt is made to separate the fetal signal from the mother's in abdominal signals in the separation phase. Two problem-solving approaches are explained; the step-by-step mode that calculates the signal at any given moment and the construction of general equations. These approaches end up calculating the variables, which stand for maternal and fetal signal. That makes it possible to achieve the separation of maternal and fetal ECGs.To Reduce the Number of Elements of Linear Antenna Arrays using Fourier's Coefficients Equating Method
http://scientiairanica.sharif.edu/article_22443.html
An analytic method is proposed to reduce the number of elements of a Uniformly Spaced Antenna Arrays (USAAs). To this end, both excitations and positions of a Nonuniformly Spaced Antenna Array (NSAA) are obtained by equating the Fourier's coefficients of array factors of NSAA to those of predesigned USAA, in two steps. At first step, the array is considered USAA and excitations of elements are determined. At the second step, the position of elements are determined for the excitations obtained in the first step. These two steps are repeated several times to increase the accuracy. In fact, this method is the extension of Fourier's Coefficients Equating (FCE) method previously introduced to design NSAAs. The effectiveness of the presented method for both pencil beam and shaped beam patterns is verified by some comprehensive examples.Comparing Different Configurations for Rotary Transformer of Wound-Rotor Resolvers
http://scientiairanica.sharif.edu/article_22444.html
Wound-Rotor resolvers are the oldest and the most widely used resolvers. They are two-phase synchronous generators with high frequency AC excitation. Rotary Transformers (RTs) are used to supply the rotating excitation winding of the resolver. Although RTs offer the benefits of contactless power transmission, harmonic contents of the secondary voltage, phase shift error between the primary and the secondary voltages, and high leakage flux are the main challenges in their usage along with resolvers. Therefore, in this paper, different configurations are examined for RT&rsquo;s ferromagnetic core to overcome the mentioned problems. All the simulations are done using 3-D time variant finite element method (TVFEM) and the best configuration is chosen for experimental prototyping and measurements. Close agreement between the simulation and the experimental test results approves the performed analysis.Coordinating a closed-loop green supply chain for remanufactured product under competition
http://scientiairanica.sharif.edu/article_22445.html
The success of any remanufacturing system depends on proper supply of used product. In the real-world, many remanufacturers are unable to collect it directly from customers. This article considers a closed-loop green supply chain consisting of a single remanufacturer, two competing retailers and collectors for dealing with used and remanufactured products. Considering the effect of acquisition price and greening level on collection quantity of used product, and the effect of selling price and greening level on the demand, closed-form solutions are derived for a centralized model and two decentralized models depending on collectors' cooperation and competition. Optimal results of the decentralized models are compared to find the best decentralized policy. Moreover, a novel multi-link two-part tariff contract among the channel members is proposed to resolve the channel coordination issue. The numerical analysis indicates that (i) cooperation between the collectors is only beneficial for themselves while competition between them is favorable from the viewpoint of the whole supply chain; (ii) utilization ratio has a noteworthy effect on the performance of the supply chain; (iii) the proposed contract assists the collectors with getting more than double transfer price and the remanufacturer to improve its profit over 21\% compared to the decentralized setting.Design optimization of coreless stator axial flux-switching motor
http://scientiairanica.sharif.edu/article_22446.html
This study aimed to provide the analytical design, optimization, and three-dimensional (3D) simulation through finite element method of a coreless stator axial field flux-switching motor (AFFSM). The motor consists of two indented rotors with a coreless stator between them consisting of a magnet and winding. First of the motor electrical and magnetic design was performed and its basic parameters were calculated. Then, the optimization of the machine was evaluated implementing the Taguchi algorithm in order to minimize the motor cogging torque. Some of the basic motor dimensions, such as the magnet length and width, the rotor tooth width and height, and the back iron thickness, were selected as optimization variables, and the best combination of these variables was obtained by changing them in a certain range to achieve the desired objective. Then, the accuracy of analytical design and optimization was evaluated through forming a 3D finite element method (FEM) of the motor and investigating its performance. Comparison of the optimized and primary motor revealed that the optimal design had a better performance than the initial. Finally, a prototype of the proposed motor was fabricated and tested, which indicated that the experimental results were largely similar to the analytical results.Copper (II) Supported on a Post-Modified Magnetic Pectin Fe3O4@Pectin~Imidazole~SO3H-Cu(II): An Efficient Biopolymer-Based Catalyst for Selective Oxidation of Alcohols with Aqueous TBHP
http://scientiairanica.sharif.edu/article_22447.html
Designing a catalyst that combines the activity, selectivity, simple recovery, and follows the green chemistry instructions is of great importance. In the present study, Fe3O4@Pectin~Imidazole~SO3H-Cu(II) was synthesized as an efficient and biopolymer-based magnetic catalyst for the oxidation of benzyl alcohols to aldehydes using tert-butyl hydroperoxide (TBHP) as an oxidant under solvent-free conditions. The catalyst was characterized using Fourier Transform Infrared Spectroscopy (FT-IR), Powder X-Ray Diffraction (XRD), Vibrating Sample Magnetometer (VSM), Field Emission scanning electron microscopy (FE-SEM), Energy dispersive spectroscopy (EDX), Transmission electron microscopy (TEM), and inductively coupled plasma (ICP) atomic emission spectroscopy. The results indicated that our catalyst was quite active in oxidizing the benzyl alcohols to their corresponding aldehydes in the presence of TBHP. The efficiency with low catalyst loading, convenient work-up, isolation of pure products, use of inexpensive metal instead of precious metals, solvent-free condition, use of eco-friendly support, and also the sustainability of catalyst up to at least 5 consecutive runs without a special drop-in activity are some of the remarkable advantages of this protocol.Numerical treatment of magnetohydrodynamic Carreau liquid with heat and mass transport containing gyrotactic microorganisms
http://scientiairanica.sharif.edu/article_22459.html
In the current examination, insightful approximations are researched for magnetohydrodynamics Carreau nanofluid having gyrotactic microorganisms over a warmed turning plate. The plate is moving with the steady uniform rakish speed. Administering conditions are gotten by utilizing certain actual presumptions as incomplete differential conditions with limit conditions. These nonlinear types of conditions are changed into coupled standard differential conditions utilizing bunch likeness change. Optimal homotopy investigation strategy (OHAM) is utilized to acquire the graphical outcomes and even qualities for the stream field factors. Graphical portrayal of speeds, temperature, fixation and thickness of gyrotactic microorganisms are examined and clarified. It is tracked down that dimensionless microorganism&rsquo;s fixation develops for bioconvective Lewis number and focus distinction variable of microorganisms. It is additionally seen that dimensionless speeds diminish because of the attractive impact and Carreau liquid boundary. Contour plots and mathematical outcomes are given for neighbourhood motion boundaries like skin rubbing coefficient, Nusselt number, Sherwood number and thickness number of motile microorganisms.A resilient supply chain network for an online retailer: a three-phase robust framework and a case study
http://scientiairanica.sharif.edu/article_22460.html
This paper proposes a three-phase robust approach to the problem of designing a supply chain in an e-tailing environment considering the resilience strategies such as fortification, backup suppliers, and transshipment. First, the scores of potential suppliers are obtained using several resilience criteria. Then, a scenario-based stochastic network design model is proposed which considers operational (demand and transfer cost) and disruption (a natural disaster) risks. Finally, an order transfer problem is solved. The results prove the effectiveness of the framework for a case study. A preferred Pareto optimal solution of the robust optimization model is selected such that its cost is only 0.15% worse than its neighbour while its score of suppliers is 2.46% greater than the mentioned point. In addition, the results of the sensitivity analysis show that although the suppliers with higher scores costs more, they have a smaller cost range.Effect of MHD on Casson fluid with Arrhenius activation energy and variable properties
http://scientiairanica.sharif.edu/article_22461.html
In the present study, MHD Casson nanofluid under the influence of exponential temperature dependent thermal conductivity and variable viscosity past a stretching surface has been scrutinize. After the application of the similarity transformations, the governing partial differential equations of the modelled problem are converted into ordinary differential equations and solution is achieved with the assistance of the shooting method. The solution obtained with the help of shooting technique is used to analyze the distribution of mass and heat flux over sheet. The influence of various governing parameters on the dimensionless velocity, temperature and concentration distribution have been analyzed and discussed in detail. The simulations of the presented model show that the surface drag is upsurged as each of the Casson parameter and temperature dependent thermal conductivity parameter is boosted whereas the rate of heat transfer is diminished. It is also observed that an increment in the temperature near the surface is noted against the thermal conductivity parameter whereas an opposite trend is observed away from the surface.Revisiting Composite Right-/Left-Handed Transmission Lines and Symmetric Couplers
http://scientiairanica.sharif.edu/article_22462.html
In this paper, some hidden aspects of composite right-/left-handed (CRLH) transmission lines (TLs) and couplers are clarified. Complete and detailed dispersion analysis of an isolated CRLH TL is presented including lossless and lossy cases based on a conventional unit cell, devised formerly. Dispersion analysis of CRLH TLs is extended form the conventional to an accurate unit cell. Capability of TLs consisting of such unit cells in supporting RLH waves is demonstrated. A pure analytical strategy is proposed for parameter extraction of CRLH TLs and symmetric couplers based on accurate circuit models. It is shown that by including loss parameters in the circuit model, there is no need to make use of curve fitting methods for parameters extraction of said couplers.Percentile bootstrap control chart for monitoring process variability under non-normal processes
http://scientiairanica.sharif.edu/article_22463.html
In the recent years, another approach named as the bootstrap method is getting popular in Statistical Process Control (SPC) specifically when the underlying distribution of the process is unknown. The bootstrap estimators are getting popularity in statistical process control due to their remarkable properties for non-normal distribution. In this paper the bootstrap control chart is developed for monitoring process variability and robustness is discussed through simulation studies. It appears that the proposed control chart for monitoring process variability based on the bootstrap method is performing better to detect out-of-control signal in a case when data follow skewed distributions. Therefore, the proposed chart is more recommendable for industrial practitioners.A generalized differential quadrature-based computational model for describing free vibrations behavior of functionally graded circular plates around buckled configuration
http://scientiairanica.sharif.edu/article_22467.html
In the present article, the vibrational behavior of buckled functionally graded (FG) circular plates with clamped and simply-supported edge conditions is described. Considering von K&aacute;rm&aacute;n&rsquo;s assumptions, the geometric nonlinearity is incorporated into the Kirchhoff plate theory and the nonlinear governing equations of motion are then derived using Hamilton&rsquo;s principle. Critical buckling load and linear natural frequencies are first calculated using the generalized differential quadrature (GDQ) method. Afterward, the postbuckling characteristics of the circular plate are obtained via solving the nonlinear governing equations, directly. By several comparative studies, the reliability of the presented model is revealed. Finally, the fundamental natural frequency of the plate is evaluated for prebuckled and postbuckled configurations. The effects of material property and boundary conditions on the static bifurcation diagram and the natural frequency of the initial undeflected and bucked plate are studied. It is found that the trend of the fundamental natural frequency changes with the applied radial load around the prebuckled configuration is unlike the one around the buckled configuration.Enhanced Automated Quantity Take-Off in Building Information Modeling
http://scientiairanica.sharif.edu/article_22468.html
Material quantity take-off is a necessary factor in estimating the cost of construction projects; accordingly, fast and precise estimations would better facilitate the overall construction process. In recent years, several Building Information Modeling (BIM) based applications (e.g., Autodesk Revit, Tekla Structure, Autodesk Navisworks Manage, and Solibri Model Checker) have emerged to assist in performing quantity take-off. Quantity take-off measurement using these applications is accurate when the elements length multiplies with their precise section area. Still, the process encounters errors when using element volumes or Industry Foundation Classes (IFC). In this study, the authors examined the embedded quantity take-off feature of these applications for sample steel and reinforced concrete structure and provided precautions in employing BIM properties. Consequently, an automated approach has been applied to facilitate an accurate quantity take-off by using an Application Program Interface (API) extracting information from a Navisworks model as well as database management systems. A case study is subsequently presented to demonstrate and validate the proposed methodology.Prediction of work-rolls failure in hot ring rolling process
http://scientiairanica.sharif.edu/article_22469.html
The work-rolls of the hot ring rolling process are subjected to various damages due to the contact with hot metal. Thermo-mechanical fatigue is one of these damages. In order to predict failure due to the thermo-mechanical stress in the work-rolls, the developed code in ABAQUS has been used. The comparison between three- and two-dimensional models and, also, thermal and thermo-mechanical response of work-rolls with variable boundary conditions has been investigated. The results have shown that by applying mechanical and thermal loads separately or simultaneously, the response of work-rolls is completely different. In the mandrel, the location of the maximum equivalent stress is on the surface, while the location of equivalent maximum stress is in the subsurface of the main-roll. By making use of cumulative damage rules and the stress life method, the thermo-mechanical fatigue life was estimated. The cumulated damage in the mandrel&rsquo;s surface was higher than subsurface regions. In contrast to the mandrel, the cumulated damage in the main-roll&rsquo;s subsurface was higher than surface regions. In hot ring rolling machines, these locations are prone to crack initiation as a result of the thermo-mechanical fatigue in the work-rolls.Optimizing weld quality of a friction stir welded AA6061/Rutile composite
http://scientiairanica.sharif.edu/article_22470.html
In the friction stir welding process, preferred joint property is vastly reliant on the selection of optimal welding conditions. The present study aims at the application of the Taguchi approach to finding out the optimal process conditions to get superior ultimate tensile strength in the friction stir welded aluminium matrix composite (AMC) joints. AMC reinforced with rutile particles which have a potential application in the aerospace, automotive, and marine industries are used in the present work. Taguchi parametric design technique was used to identify the influence of rotational speed, tool traverse speed, and tool geometry on joint strength. Taguchi approach confines the optimum level of process variables and optimization of these variables was performed based on this study. Investigation reveals that the parameters within the chosen range of values, critically affect the output. The predicted value of the output response is 155.48 MPa which was validated by conducting further trials with optimum process variables. ANOVA results indicated that the UTS of the composite joint is mainly affected by the tool traverse speed followed by rotational speed, and tool geometry. The microstructural study unveiled that grain size is dependent on process variables and finer grains offer better joint propertiesControl of active suspension system in the presence of nonlinear spring and damper
http://scientiairanica.sharif.edu/article_22475.html
Two methods which are computationally simple and easy to apply are developed by using state dependent Riccati equation (SDRE) approach and approximating sequence of Riccati equation (ASRE) approach to control active suspension system in the presence of nonlinear spring and damper. Additionally, effectivenesses of the both control methods developed by utilizing two recently introduced SDRE and ASRE techniques are compared. First, methodologies of both approaches are presented. After that, nonlinear dynamics of the vehicle suspension system is described in terms of conveniently selected state variables for better control performance. Then, a cost function is written by using suspension and tire deflections, sprung mass velocity and acceleration, and unsprung mass velocity variables to improve ride quality, suspension deflection, and tire deflection. Additionally, a convenient representation of this cost function in terms of state variables is obtained to realize better control. A bump expressed as sinusoidal function and roughness of the road expressed as white noise are taken into consideration as the disturbances from the road. Finally, quarter vehicle suspension system equivalent model of Ford Fiesta Mk2 is used as an example and simulations obtained by using the developed control methods are checked against the performance requirements and corresponding passive suspension system.A Triband EBG Loaded Microstrip Fractal Antenna for THz Application
http://scientiairanica.sharif.edu/article_22476.html
Future wireless communication needs antenna with multifunctional operation. This paper focuses on Terahertz Antenna that could be easily integrated with micro and nano devices. In this paper, an octagonal shaped Microstrip Fractal Antenna loaded with the EBG structure is designed for tri-band terahertz application. Triple band characteristic achieved by fractal radiating patch is loaded with Electronic Band Gap (EBG). The antenna is working on triple band characteristics at 948 GHz, 984GHz and, 1040 GHz with overall dimensions of 700x900 &micro;m2. The result and performance show that the recommended antenna will be compatible with compact wireless devices and Monolithic Microwave Integrated Circuit (MMIC). All simulation work has been done using electromagnetic software Ansoft High Frequency Structure Simulator (HFSS) and CST studio suite. The electromagnetic features like S11 parameters, VSWR, gain, efficiency and the radiation characteristics of such antenna are also explored. The simulation results show that this antenna has 9 dB realized gain at 0.948 THz resonating frequency.Optimizing A Fuzzy Multi-Objective Closed-loop Supply Chain Model Considering Financial Resources using meta-heuristic
http://scientiairanica.sharif.edu/article_22477.html
This paper presents a multi-objective mathematical model which aims to optimize and harmonize a supply chain to reduce costs, improve quality, and achieve a competitive advantage and position using meta-heuristic algorithms. The purpose of optimization in this field is to increase quality and customer satisfaction and reduce production time and related prices. The present research simultaneously optimized the supply chain in the multi-product and multi-period modes. The presented mathematical model was firstly validated. The algorithm's parameters are then adjusted to solve the model with the multi-objective simulated annealing (MOSA) algorithm. To validate the designed algorithm's performance, we solve some examples with General Algebraic Modeling System (GAMS). The MOSA algorithm has achieved an average error of %0.3, %1.7, and %0.7 for the first, second, and third objective functions, respectively, in average less than 1 minute. The average time to solve was 1847 seconds for the GAMS software; however, the GAMS couldn't reach an optimal solution for the large problem in a reasonable computational time. The designed algorithm's average error was less than 2% for each of the three objectives under study. These show the effectiveness of the MOSA algorithm in solving the problem introduced in this paper.C & Circular Shaped Barriers Optimization in a Synchronous Reluctance Rotor for Torque Ripples Minimization
http://scientiairanica.sharif.edu/article_22478.html
Due to the lack of magnets and the suitable final price, synchronous reluctance motors are potential applicants for household electric appliances and so on. But in general, they suffer from high torque ripple. Optimized design of the synchronous reluctance rotor structure is presented for two different types of barrier shape with aiming to reduce the torque ripple along with increasing the average torque.In this paper, the optimization of rotor geometries with a fixed machine size for C-shaped barriers and circular barriers type is investigated. Most of the rotor parameters such as the width of iron parts, and the width of barriers along d and q axis are optimized by a new method using the PSO algorithm. Besides, the angle of end points for each barrier with constant rib and insulation factor are considered in optimization process. Minimizing the torque ripple without losing or even increasing the average torque is the most critical optimization achievement. Two prototypes of the optimized rotor with the C-shaped and circular barriers type have been fabricated and experimentally compared. The results obtained from the 2-D Finite Element Simulation of the recommended machine conform well to the experimental result.A simulation study: Robust ratio double sampling estimator of finite population mean in the presence of outliers
http://scientiairanica.sharif.edu/article_22480.html
In this study, we suggest a family of ratio estimators for the population mean parameter using various robust regression techniques. These robust regressions techniques are Huber MM, LTS, and LMS estimates. We evaluate the performance of estimators in terms of the mean square error (MSE), and we compare the efficiency of our proposed robust-regression-ratio-type estimators with existing estimators under the optimal conditions. These comparisons show that our robust ratio-type estimators give more efficient results than the existing estimators under double sampling. In addition, the simulation and the empirical studies based on a data set that includes unusual observations show that our proposed estimators have a lower MSE than the existing estimators.An efficient synthesis of pyrimido[4,5-b]quinoline and indenopyrido[2,3-d]pyrimidine derivatives in the presence of Fe3O4@nano-cellulose/Sb(V) as bio-based magnetic nano-catalyst
http://scientiairanica.sharif.edu/article_22481.html
In this study, an eco-friendly approach has been introduced for the synthesis of pyrimido[4,5-b]quinolones and indenopyrido[2,3-d]pyrimidines. This synthesis was done via a three component coupling of 6-amino-2-(methylthio)pyrimidin-4(3H)-one, 1,3-indanedione/dimedone and aromatic aldehydes using Fe3O4@nano-cellulose/Sb(V) as catalyst under solvent-free condition at 70 &deg;C by electrical mortar-heater. The catalyst was separated from the reaction mixture by an external magnet and reused for subsequent reactions. The present procedure offers many advantages such as high yield, easy work-up, simple isolation of catalyst by external magnet and high reusability of the it. The structure of the obtained pyrimido[4,5-b]quinolones and indenopyrido[2,3-d]pyrimidines products were studied by FT-IR, 1H-NMR and 13C-NMR spectroscopic data.Magneto-hydrodynamic mixed convective heat transfer in a nanofluid filled wavy conduit having rotating cylinders
http://scientiairanica.sharif.edu/article_22482.html
Flow and thermal characteristics of mixed convection in a nanofluid filled wavy conduit was numerically investigated in this study. The conduit was considered to contain a pair of rotating cylinders. It was heated and cooled from its lower and upper wavy surface, respectively. The rotating cylinders were placed along the centerline of the wavy conduit. It was also permeated by an external magnetic field. Finite element method was implemented to simulate the conservation equations. Based on the current investigation, a new model was developed for improving thermal conductivity of nanofluids inside a wavy conduit. In addition, a detailed parametric study was presented to visualize the effects of governing parameters on the flow structure and temperature field in the conduit. The numerical results indicated that the physical parameters noticeably influenced both fluid flow in terms of streamlines, velocity profiles and temperature distributions in terms of isotherms, average Nusselt number. The rotating cylinders, wavy surfaces and the inclined magnetic field were found to have the most significant effect on the heat transfer mechanism. Maximum heat transfer occurred as the magnetic field was placed at an angle of 90o.Roll restoring coefficients of planing boats’ maneuver using 2D+t approach
http://scientiairanica.sharif.edu/article_22483.html
Importance of maneuverability as a main feature of safety for a marine craft is broadly recognized. Mathematical modeling together with Maneuver Hydrodynamic Coefficients (MHCs) is employed for maneuverability simulation. Generally, experimental, analytical and numerical methods are employed for extraction of MHCs which 2D+t approach is recently employed. In this study, roll restoring MHCs of planing hulls are evaluated by the 2D+t approach. Running attitude of planing boats alters during any kind of maneuver due to forward speed change. This study presents a simple and applicable PMM procedure for consideration of running attitude to extract MHCs. In this procedure at a given forward speed, the planing hull is restrained to PMM apparatus in a fixed running attitude resulted from conventional resistance test at the same forward speed. This procedure is employed by 2D+t method for prismatic planing hulls in a set of forward speeds in roll condition. It has resulted three regression formulae for Y_ϕ, K_ϕ and N_ϕ as function of dead-rise angle and Froude number. The result of this study can be directly used in simulation of maneuvers via mathematical model. Moreover, this approach may be followed for other MHCs related to sway and yaw motions in future work.Joint optimization of pricing, inventory control and preservation technology investment under both quality and quantity deteriorating
http://scientiairanica.sharif.edu/article_22484.html
This study presents a model for inventory control of deteriorating product in which both quantity and quality deterioration of the products are considered overtime. In this regard, for maximizing the profit, a new model is developed through two concepts: (1) establishing a decreasing pricing policy that depends on quality in order to prevent the decline in demand and product quality deterioration, and (2) investigating the level of investment in preservation technology as a significant solution in affecting the product deterioration rate. Consequently, it maintains the quality of products and increases their expiration date. In addition, the time value of money and inflation are well noticed in making the calculation of financial flows more accurate. To demonstrate the characteristics of the model, two comparative studies are conducted. The first one emphasizes the increase in the total profit of the inventory system caused by dynamic pricing policy, and another establishes the major impact of paying attention to the time value of money and inflation on making decisions.Many-objective optimization for construction project scheduling using non-dominated sorting differential evolution algorithm based on reference points
http://scientiairanica.sharif.edu/article_22485.html
Project scheduling has become one of the critical concerns of the construction project's success. In recent years, global construction markets have become increasingly competitive, and the number of project stakeholders has grown significantly. These issues have required concurrently reaching competing objectives, such as optimizing the time, resources, cost, environmental impact, safety risks, and quality of a project. Several types of research efforts have focused on multiple-objective construction scheduling models to deal with these objectives. However, there is still a need to integrate all these objectives in the scheduling process to consider most aspects of a project. In order to fill this gap, a many-objective optimization model considering time, cost, resource, environmental impact, safety, and quality based on a newly developed many-objective optimization algorithm, Non-dominated Sorting Differential Evolution algorithm based on Reference points (NSDE-R) is presented in this study. To determine the most proper schedule based on project priorities, the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) merged with the optimization algorithm. The proposed model's applicability demonstrated employing a case study of a building construction project.Optimizing a bi-objective multi-period fish closed-loop supply chain network design by three multi-objective meta-heuristic algorithms
http://scientiairanica.sharif.edu/article_22490.html
Attention to a food supply chain has increased recently due to population growth and increased demand for food. Aquaculture development is advantageous as fish is a crucial constituent of the food basket of households. This study first presents a new bi-objective and multi-period mathematical model of a fish closed-loop supply chain (CLSC). The model is addressed by utilizing the multi-objective Keshtel algorithm (MOKA), NSGA-II, and MOSA). The Taguchi method is employed to tune these meta-heuristics to attain superior performance, and the &epsilon;-constraint method is used in solving small-sized problems to validate them. The results show that the exact method cannot solve large-sized problems. The solutions are compared in terms of different performance metrics. Utilizing the &lsquo;ﬁltering/displaced ideal solution&rsquo; DIS method, NSGA-II and MOKA with a direct distance of 0.4228 and 0.8976 have the first and second performance ranks, respectively. Also, a case study including a trout CLSC in the north of Iran is investigated. The results and the case study show that the developed model can be applied to the proposed solution approach.Investigation on opportunities and challenges of cross-border electricity trade for Iran
http://scientiairanica.sharif.edu/article_22498.html
Energy demand in Iran is increasing because of many reasons, for instance, low price, population and GDP growth. Its trend shows that this situation could not continue for many years, so it needs reviewing in energy policy in Iran. The aim of this paper is reviewing the whole energy system of Iran and its possible future and offering some policies for solving current and future problems. First of all, this study investigates the trend of growth of some parameters like GDP, electricity price, population, CO2 emission and electricity consumption in eight years. After that, by calculating the price of electricity generated in Iran under three different circumstances, this study is able to investigate the electricity and natural gas trade according to the price of them. Studying the renewable energy effects on CO2 emission reduction, subsidy reduction and water saving lead this study to prepare and policy offer. At the end of this paper, results show there is a lack of idea in energy economic in Iran, and two policies will be offered by considering this aspect.Convection Heat Transfer and Flow Phenomena from a Rotating Sphere in Porous Media
http://scientiairanica.sharif.edu/article_22499.html
The study of the flow and convective heat transfer from rotary sphere in fluid mechanics, astrophysics and astronaut subjects are important. Today, porous mediums use has become widespread because of the heat transfer characteristics as well as their lightweight and low volume. Many numerical studies in heat transfer and fluid mechanics have been done regarding rotary sphere. The present project studies the phenomena of flow and heat transfer due to the rotation of the sphere at a constant temperature around itself in a porous medium, assuming a laminar, steady and incompressible flow. Analytical solution of equations used are based on power series and the porosity coefficient is assumed between 0 to 1in this problem. In the spherical coordinate system used here, changes in azimuthal angle direction are ignored and the body force and pressure gradient for the problem are considered zero. The presence of porous medium is expected to increase thermal parameters.T-spherical Fuzzy Soft Matrices with Applications in Decision Making and Selection Process
http://scientiairanica.sharif.edu/article_22500.html
In the present communication, we have introduced the notion of T-spherical fuzzy soft matrix (TSFSM) and studied various types of associated binary operations and properties. In literature, it has been observed that the concept of soft matrix plays a vital role in many engineering applications as well as to cater different socio-economic and financial sector problems. As per the definition of T-spherical fuzzy set, the proposed notion would have an additional capability to address the impreciseness of the information close enough to human opinion mathematically.Further, on the basis of the structure of proposed TSFSM and using the concept of choice matrix along with its weighted form, a new algorithm for the decision-making process has been outlined. Next, utilizing the score/utility matrix, we present another algorithm for the selection process. For the sake of understanding of the proposed methodologies, illustrative examples have also been presented. Some comparative remarks for the proposed techniques in contrast with existing techniques have been listed for a better readability and understanding.Design, Optimization, and Control of a Linear Tubular Machine Integrated with Levitation and Guidance for Maglev Applications
http://scientiairanica.sharif.edu/article_22501.html
Nowadays, with the increase of population, demand for efficient public transportation systems has increased. Magnetic levitation (maglev) trains are one of the best choices for the future. There are three separated systems in a classical magnetic train to achieve desirable performance. Hence, several control systems and sensors are essential for train operation. Accordingly, the classical maglev trains include complex structures, and they are so expensive. This paper presents the design, optimization, and control of a combined magnetic train structure with the integrated performance of suspension and guidance and a complementary propulsion system. These combined topologies provide a simple design, more convenient movement, and reduce construction and operation costs.A Position Sensorless Control of an Axial Flux-Switching Permanent-Magnet Motor Based on High-Frequency Pulsating Voltage Vector Injection
http://scientiairanica.sharif.edu/article_22502.html
Flux-switching permanent magnet (FSPM) machines are novel brushless machines having magnets in the stator and currently are under intensive research due to their novel features, such as simple and robust rotor, flux focusing effect, sinusoidal phase back-EMF, high torque/power density and high efficiency. In this paper, a sensorless high-frequency sinusoidal signal injection scheme for a novel yokeless and segmented armature axial flux-switching sandwiched permanent-magnet motor (YASA-AFFSSPM) is proposed. Firstly, pulsating voltage injection is investigated in detail. In addition, a simpler method (Direct signal process method) for position error signal processing is presented based on pulsating signal injection. The principle and the realization of this method are analyzed in depth. Through experiment, the traditional signal process method and direct signal process method with high-frequency pulsating sinusoidal signal injection are compared to verify the validity these methods.Toward sustainability in designing agricultural supply chain network: A case study on palm date
http://scientiairanica.sharif.edu/article_22503.html
Nowadays, the agricultural and food supply chains have attracted both academia and industrial practitioners. This paper first considers the characteristics of the date product as one of the most well-known and rich fruits to design and address its supply chain design. Special characteristics in date products have made the design of the supply chain to be unique. Therefore, considering different customers along with the specific product flow is another contribution of this paper. Reportedly, there is no work on this topic. Several old and recent meta-heuristic algorithms are utilized in multi-objective meta-heuristics to reach better intensification and diversification trade-offs. By the Taguchi design experiment method, appropriate parameter values of the proposed algorithms are chosen. Besides, the solution quality is investigated by approaches including the relative percentage deviation (RPD) and the CPU time and the weighted LP-metric method. The results showed that a multi-objective Keshtel algorithm (MOKA) is more efficient and consistently outperforms other utilized algorithms.Influence of humic acid on adsorption of methylparaben from aqueous solutions onto commercially available granular activated carbons
http://scientiairanica.sharif.edu/article_22535.html
The adsorption of methylparaben (MP) on Calgon carbon (F400) and Norit-type granular activated carbons (GACs) from aqueous solutions was examined. The influence of humic acid (HA) on adsorption of MP under different pH conditions was evaluated. The adsorption isotherm results are well described by Freundlich model. The MP adsorption capacity on F400 and Norit GACs was found to be of 150 mg/g. In the presence of 2.357 mg/L HA total organic carbon (TOC), the maximum MP adsorption capacity on F400 GAC at pH 7 was increased to 2.2 folds. The Norit-type GAC had a comparatively higher uptake capacity of MP than F400 GAC. The key mechanism for MP adsorption onto the F400 GAC was through the hydrogen interaction between &ndash;OH functional group of the MP molecules. The MP adsorption capacity on Norit GAC was increased from 5 to 100 mg/g at pH 7.Modified Tumor Diagnosis by Classification and Use of Canonical Correlation and Support Vector Machines Methods
http://scientiairanica.sharif.edu/article_22536.html
The main objective of this research is to investigate techniques for classifying tumor grades based on image processing. The algorithms to classify tumors are introduced, and their performance for the experimental results are investigated. In the proposed algorithm, first, the scan images of the lung are pre-processed, and then the histogram, texture, and geometric features are extracted. These features are then used in the Support Vector Machines (SVM) and Canonical Correlation Analysis (CCA) classifiers to diagnose tumors and classify benign and malignant types. These combined techniques in understanding medical images for researchers are an essential tool to increase the accuracy of diagnosis. In this paper, simulated and real medical images are used. The results obtained from the proposed methods in this paper were compared with the previous findings to approve the proposed approach's efficacy and reliability in diagnosing and classifying tumors. In addition to high accuracy in diagnosis, this method is also a low-cost and low-risk method. Due to its very high sensitivity and having the desired values of two criteria of precision and specificity, and the low number of features used for classification, the developed method was proposed as an efficient and appropriate method for tumor classification.Reliability Evaluation of Software Architectural Styles Based on Correlated Component Failure
http://scientiairanica.sharif.edu/article_22537.html
The aim of this study is to provide an efficient and scalable way to evaluate the reliability of different &lrm;software ar-chitectural styles with regard to correlated components failures. In this way, a method &lrm;based on the discrete time Markov chain (DTMC) model is proposed. In the proposed method, software architecture styles are used for reliability evaluation. The four main styles are transformed into Markov chain models and the transfer matrix is created for them, then using the Bernoulli distribution, the correlation between component is shown in the matrix and used in the evaluation process. The proposed method is scalable &lrm;such that it can be used for large software architectures with heterogeneous and homogeneous &lrm;styles. The results of the evaluation on the case study show that this method is more accurate than &lrm;the other methods for reliability prediction of the software architectures. As a result, it is &lrm;concluded that the proposed method is suitable for the preliminary estimation of the software &lrm;architecture reliability and can make a better comparison between various architectural styles to &lrm;choose the best and most suitable one from the available options.&lrm;Monitoring Lifetime Data for a Failure Censoring Reliability Test with Replacement Using Shewhart Type and Exponentially Weighted Moving Average Control Charts
http://scientiairanica.sharif.edu/article_22538.html
Lifetime data has two distinguishing features: they are usually censored and have non-normal distributions. Generally speaking, censoring schemes can be classified into (i) censoring schemes with replacement and (ii) censoring schemes without replacement. Replacement during a life testing means that once observing a failure item, it is replaced by a new one. While there is a relatively large body of literature regarding control charts under censoring schemes without replacement, i.e., the second type schemes, designing control charts for the first type schemes has not yet received considerable attention. In this paper, two types of control charts are developed to monitor the lifetime data of an exponentially distributed item. To obtain the information of the lifetime data, failure censoring is conducted: n items are randomly selected and put on the test simultaneously. The test continues until observing r (r&le;n) failures. During the test, once observing a failure time, it is replaced by a new one. Development of Shewhart type and exponentially weighted moving average control charts under failure censoring with replacement is the main novelty of the current study. Comparative and simulation studies are conducted. ARL curves are also derived with respect to different parameters of the process.Monitoring Coefficient of Variation Using Variable Sampling Interval Double Exponentially Weighted Moving Average Charts
http://scientiairanica.sharif.edu/article_22539.html
As a measure of relative variability, the coefficient of variation (CV) is a valuable charting statistic in statistical process control. Great efforts have been devoted to monitoring CV efficiently. To further improve the performance of CV charts, this paper proposes three Double Exponentially Weighted Moving Average (DEWMA) charts by incorporating Variable Sampling Interval (VSI) strategies to monitor the CV squared. The run length properties of the proposed charts are evaluated via Monte Carlo simulations. Comparative studies show that the proposed VSI DEWMA CV charts detect the process shifts faster than the existing CV charts. A real data example is presented to illustrate the VSI DEWMA CV charts.Behaviour of Concentrically Braced Steel Frames under Fire Loading
http://scientiairanica.sharif.edu/article_22540.html
Knowing how a steel structure behaves under fire loading is of vital importance, given a large number of events in recent years have proved the vulnerability of steel structures under this type of hazard. Older concentrically braced frames have been widely used in buildings without observing seismic provisions and details. Although the vulnerability of this type of structural system, here referred to as non-seismic braced frames, has been studied under earthquake loading before, its behaviour under fire loading has not been investigated yet. This paper investigated the behaviour of global and local responses of the mentioned structural system under various uniform fire scenarios. The heating and cooling phases of fire were taken into account for different building stories using the finite element method. The results of analyses showed that the braces buckled at high temperatures due to the large compressive axial forces and expansion of lateral constraints. This phenomenon led to the early loss of lateral resistance of stories, which, in turn, resulted in the failure of columns. Consequently, the underlying floor collapsed under fire. The analysis results contribute to a better understanding of the behaviour of steel braced frames under fire conditions and the corresponding local and global responses.Analysis of Loading Distribution for SRB and TSRB Combined Bearing
http://scientiairanica.sharif.edu/article_22541.html
Combined bearing, which consists of spherical roller bearing and thrust spherical roller bearing, is an important support in various low-speed and heavy load institutions and the stability of its running state is a strong guarantee for the normal operation of the supporting mechanism. Basing on the wellbore trajectory control tool, the loading distribution of combined bearing under pure radial and axial forces is studied theoretically. Two kinds of limit state of rolling elements movement named "Odd press" state and "Even press" state is considered and the Hertzian line elastic contact model is used to deal with the contact between roller and raceway. The calculation results of contact stress and radial displacement are very close to the analysis results, and the accuracy of the analysis results is verified by the radial displacement experiment. The results show that the radial load will lead to the radial displacement of the combined bearing axis, which is about 5.81&times;10-3 mm. The radial displacement can affect the guiding accuracy of the tool to a certain extent. The radial displacement can be reduced by adjusting the bearing structure design parameters .This research can be used to design SRB and TSRB combined Bearing in actual engineering problem.Effectiveness of a vertical micropile system for mitigation of liquefaction induced lateral spreading effects on pile foundations: 1g large scale shake table tests
http://scientiairanica.sharif.edu/article_22542.html
Liquefaction-induced lateral spreading has caused severe damages to pile foundations during past earthquakes. Micropiles can be used as a mitigation strategy against lateral spreading effects on pile foundations. However, the available knowledge regarding the possible efficiency of such a strategy is quite limited. In this paper, the effectiveness of a vertical micropile system as a lateral spreading countermeasure was evaluated using large scale 1g shake table tests on 3&times;3 pile groups. The results showed that the micropile system was not able to effectively reduce bending moments in piles while it reduced lateral soil pressures exerted on the upslope piles of the group by the upper non-liquefiable layer. The employed micropiles restricted lateral displacement of the upper non-liquefiable layer and partially that of the liquefiable layer, especially at upper depths. Solutions such as increasing the number of micropiles with a tighter pattern, using stiffer micropiles or fixing them in the underlying non-liquefiable layer can enhance their performance.Numerical investigation of circular porous fins effect on natural heat transfer enhancement in an annulus cavity
http://scientiairanica.sharif.edu/article_22543.html
An asymmetric numerical study has been performed to investigate the effect of utilizing circular porous fins on heat convection inside of an annulus enclosure. The walls are considered to be at a constant temperature. The porous fins are installed on the outer wall, and other walls are insulated. Governing equations discretized using the FVM based on the second-order upwind scheme. The effect of different parameters on heat transfer enhancement inside the annulus, such as annulus inclination angle, annulus aspect ratio, Darcy number, Rayleigh number, thermal conductivity, the position of fins, number, and length of fins, has been investigated. Results declared that increasing Darcy number from a certain value would enhance the average Nusselt number dramatically at both aspect ratios, even though annulus with an aspect ratio of 3:1 has a higher value of average Nusselt number compared to the aspect ratio of 2:1. It has been illustrated utilizing low relative solid to fluid phase thermal conductivity nullify the effect of the increasing number of porous fins on heat transfer enhancement but, by increasing relative thermal conductivity to Ke=100, installing four porous fins on the inner cylinder increases the average Nusselt number by 7 percent compared to using only one fin.Improving thermal performance of a solar thermal/desalination combisystem using nanofluid-based direct absorption solar collector
http://scientiairanica.sharif.edu/article_22544.html
Depletion of freshwater resources and reduction of rainfall in arid areas causes water scarcity, which is intensified by population and urbanization growth. In this study, a small-scale solar thermal/desalination combisystem using nanofluid-based direct absorption solar collectors and humidification-dehumidification desalination unit is proposed to supply domestic hot water, space heating, and freshwater demands of a residential building. The dynamic simulation of the system performance in the Hot-Dry climate zone is done using TRNSYS-MATLAB co-simulator. The results indicate that using the proposed combisystem reduces 94.3% and 17% of annual energy consumption for providing domestic hot water and space heating demands, respectively. The freshwater demand is supplied in the range of 11.3% to 100%. In the case of using a flat plate solar collector, the solar fraction for domestic hot water and space heating demands in comparison with nanofluid-based direct absorption solar collectors reduces by 3.7% and 1.7%, respectively. Furthermore, the produced freshwater reduces 18% on average. The payback time using nanofluid-based direct absorption and flat plate solar collectors are 6.4 and 7.8 years, respectively.Robust State-Feedback Controller for Linear Parameter Varying Systems with Time-Invariant Uncertainties
http://scientiairanica.sharif.edu/article_22545.html
In this paper, the robust gain-scheduled state-feedback controller problem is studied for uncertain linear parameter-varying systems whose state-space representations are the linear combination of the uncertain time-varying parameters including time-invariant parametric uncertainties (TIPU). It is supposed that these uncertainties are bounded by the given intervals and cannot be pulled out as an uncertain block. It is considered a serious challenge because the exact information about the plant dynamics cannot be extracted from the uncertain time-varying parameters. This is while; the gain-scheduled controllers need to have the exact information about the plant dynamics to satisfy the desired control purposes. To handle this challenge, we introduce a state-feedback gain, which is formed by a set of the new scheduling parameters and a secondary time-varying term. The stabilization conditions are obtained in terms of the linear matrix inequalities (LMIs). The effectiveness of the proposed method is shown using an example.Novel Design of Natural Double-Pass Solar Air Heat for Higher Thermal Performance by Exploitation of Vortex Generator
http://scientiairanica.sharif.edu/article_22548.html
In this paper, the effects of flapping flexible vortex generators in a two dimensional turbulent free convection airflow in a double-pass solar air heater are discussed. Two thin elastic winglets, used here as vortex generators, are attached on two absorber walls near the inlet section with the attack angle of 65o. This novel concept is demonstrated using transient numerical simulation of the flow field by the finite element method with considering the Fluid-Solid Interaction. In this work, an extensive comparison is made between four different configurations. The absorber and outlet temperatures, as well as flow rate and velocity field, are discussed in detail and the numerical findings reveal considerable thermal performance enhancement in comparison with conventional parallel double pass heater. The improvement up to 54% in the ∆T ̅=T ̅_out-T_in , from 13 to 20 o C, while reducing 33.6% flow rate. The present numerical results are validated against the experimental and numerical data reported in the literature.Mathematical modeling of PMSG-based wind power plants (WPPs) for harmonic resonance studies and analytical assessment of wind turbines converters controls on WPP harmonic resonance response
http://scientiairanica.sharif.edu/article_22549.html
In this paper harmonic resonance analysis of the grid comprising wind power plants (WPPs) with permanent magnet synchronous generators (PMSGs) is presented. Usually, Norton equivalent circuit is used as the wind turbine (WT) model for harmonic resonance studies, in which, WTs are simply modeled as ideal current and voltage sources and impacts of converters controls on the WTs output impedances are neglected. This paper deals with the harmonic resonance analysis of study WPP system taking the impacts of converters controls, and current and voltage measurement filters into account. In this way, harmonic impedance models of the WTs are presented for simple and detailed cases, and then WT harmonic impedance is extracted for the mentioned cases. Next, results of frequency scan and harmonic mode resonance analyses for different cases are given and compared, and then effects of the current and voltage measurements filters and WT converter control on harmonic resonance analysis of the study WPP system are presented. It is shown that increasing the bandwidth of the grid-side converter current control loop can not shift the resonant frequencies, but enhances the system damping, and consequently reduces the driving point impedances in the resonant frequencies.Ground Vehicle and UAV Collaborative Routing and Scheduling for Humanitarian logistics using Random Walk Based Ant Colony Optimization
http://scientiairanica.sharif.edu/article_22550.html
A well-planned humanitarian logistics involving rescuing people and providing on-time lifesaving facilities to disaster-affected areas can significantly mitigate the aftermath of disasters. However, damaged bridges and blocked roads can hinder last-mile deliveries in disaster-affected areas by ground vehicles only. So, in this paper, we propose a ground vehicle (GV) and unmanned air vehicle (UAV) collaborative delivery system in such areas. Here, a fleet of homogenous ground vehicles each equipped with a certain number of UAVs is deployed for last-mile deliveries. UAVs make the flight from GVs, deliver to end locations and return to the GV for battery replacement and/or start another flight. The objective of the model is to minimize the total delivery time within UAV flight endurance and payload constraints. Firstly K-means clustering algorithm has been used to cluster the disaster-affected region into different sectors. Then GV_Touring and UAV_Routing have been scheduled using nearest neighbor heuristic to serve ground approachable locations and UAV served locations respectively. Finally, the random walk based ant colony optimization-based (ACS_RW) has been developed to further optimize the overall travel time. Experimentation results show the potential benefits of the proposed algorithm over other available truck-drone collaborative transportation models.Fast and Secure Angular-Based Detection Algorithm for Reverse Power Occurrence in Synchronous Generators
http://scientiairanica.sharif.edu/article_22551.html
Reverse power (RP) phenomenon in synchronous generators may lead to severe damage to the generator prime mover due to motoring action of the generator. The operation of the usual technique, which detects RP on the basis of current direction, is too slow because of utilization of intentional time delay in the relay structure. The deliberate time delay helps the relay to avoid tripping during unwanted disturbances. This paper proposes a novel angular-based scheme to detect RP in synchronous generators. For this, the proposed technique uses the load angle (&delta;) and the phase difference between voltage and current (&theta;), as the angular quantities of the generator. Furthermore, other electrical parameters of the generator such as current and voltage are also utilized as the supplementary parameters for RP detection. Ultimately, this contribution uses the analysis of vertical component of E_A (E_A Sin&delta;) and also the tangential component of I_A on V (I_A Cos&theta;) in the generator phasor diagram for making the final decision. To verify the performance of the angular-based technique, extensive simulations are carried out on two sample systems (single machine and three machines infinite bus), under different conditions and the final results show the satisfactory performance of the proposed algorithm.On use of subsampling of the non-respondents for estimation of distribution function
http://scientiairanica.sharif.edu/article_22558.html
In this study, we propose a general class of estimators of the finite population distribution function (DF) using two auxiliary variables under subsampling of non-respondents. We use the Hansen and Hurwitz [1] pioneered model in our subsampling technique. Layout of response and non-response classes are discussed in various tables in detail. Expressions for the biases and mean square errors (MSEs) of the estimators are obtained up to first order of approximation. We also obtain the conditions by comparing the proposed estimator with existing estimators. Three real data sets are used to support the theoretical findings. In our findings, it is observed that the proposed class of estimators is more efficient as compared to all other existing estimators including the usual mean estimator, ratio estimator, exponential-ratio estimator, traditional difference estimator, Rao [2] difference estimator, Kumar et al. [3] estimator and many other recent difference type estimators by using the criterion of MSE.Nurse scheduling problem by considering total number of required nurses as well as nurses’ preferences for working shifts: An algorithmic game-theoretic approach
http://scientiairanica.sharif.edu/article_22559.html
In this paper, nurse scheduling problem (NSP) is studied by minimizing the total number of the required nurses as well as by maximizing the nurses&rsquo; preferences for working shifts. In this setting, hospital&rsquo;s managers set the total number of the required nurses while nurse-chiefs select the required part-timers and then assign shifts to all nurses including the full-timers and the selected part-timers. Obviously, competition between the managers and nurse-chiefs to make decisions leads to a conflict between their objectives. In this point of view, a two-player game-theoretic framework can be established between them to set decisions. To our knowledge, this study is the first one that develops the game-theoretic approach to solve the NSP. In this setting, four game-theoretic models, including Managers-Stackelberg, Nurses-Stackelberg, Nash, and Centralized, are proposed based on the various competitive and cooperative interactions between the players. Moreover, a mathematical programming model is developed to obtain the equilibrium strategies. It is found that the managers and nurse-chiefs gain their best responses under the Managers-Stackelberg and Nurses-Stackelberg games, respectively. In the Nash game, they make decisions in order to meet their objectives, mostly. Moreover, the equilibrium strategies given by the Managers-Stackelberg and Centralized games are the same.Residential Demand Response Coordination for Distribution Network Reliability Enhancement
http://scientiairanica.sharif.edu/article_22561.html
This paper establishes a centralized model to activate residential demand response in order to improve distribution network reliability. The model aims at minimizing the damage cost imposed by load curtailments following occurrence of unexpected events. In this model, distribution system operator (DSO) and responsive customers have already signed a contract authorizing the DSO alters the operation of responsive appliances whenever system reliability is jeopardized. The model addresses consumers&rsquo; preferences and guarantees that the operation of appliances is displaced within the bounds defined by the owners. Once an unexpected event occurs, the DSO commits responsive appliances to avoid likely violations in the network operational limits and costly load curtailments. The proposed model is mathematically formulated in the form of mixed integer linear programming (MILP) and its capability is depicted via applying to a real-world distribution network with some residential consumers. The comparison of service reliability indices after and before utilizing demand response potentials illustrates the effectiveness of the model.Experimental and numerical probe into the effects of adding one and two steps to a mono-hull planing vessel on its performance in calm water
http://scientiairanica.sharif.edu/article_22562.html
In the current study, two different vessels with a single step and two steps are experimentally and numerically studied. The considered speeds are 8 and 9 m/s, equivalent to beam Froude numbers of 3.44 and 3.86. The experimentally measured parameters include bow rise-up, trim, and vessel&rsquo;s resistance. On the other hand, numerical simulations of fluid flow around the vessel at 10 m/s and 12 m/s speeds are conducted using STAR-CCM+ software. Two-phase flow is analyzed using finite volume method and volume of fluid technique. Moving mesh approach through the Overset technique is applied for discretization of the domain. Based on the experimental results, it is observed that addition of the transverse step enhances the vessel&rsquo;s stability and reduces its trim. It is also concluded that the resistance of a single stepped high-speed vessel reduces, compared to a vessel of without step. Meanwhile, numerical studies indicate that as the second step moves away from the transom, the resistance increases, and trim decreases. It is also concluded that both single-step and two-step models are stable at speeds up to 12 m/s.A comparative study between lithium-ion battery and Pb-acid battery-supercapacitor hybrid energy storage system for frequency control and Energy management of islanded microgrids
http://scientiairanica.sharif.edu/article_22563.html
Among various storage technologies used for the energy storage systems, the supercapacitors, the Pb-acid-Batteries (PABs) and the lithium-Batteries (LBs) are widely used for microgrid applications. The supercapacitors with high-power density are suitable for fast power regulations; conversely, the PABs have high-energy density, which makes them suitable for long-term energy management. Since the PABs and the supercapacitor can complement each other deficiencies, their combination as a hybrid energy storage system is used. However, the LB has both high-energy and high-power densities. Therefore, an LB Energy Storage System (LBESS) can similarly function like a Pb-acid battery-supercapacitor-hybrid-ESS (PSHESS). This paper tends to determine which one is technically and economically more suitable for applications in islanded microgrids. For this purpose, a frequency control and energy management scheme is proposed. It maintains the balance between demand and supply, and also keeps the microgrid frequency within safe operational limits using the least needed sizes for the energy storage systems. Simulation results reveal the costs of LIBESS and PSHESS would be $140325.93 and $209408.37, respectively, which shows that the cost of the PSHESS is $69082.44 or almost 49.2 % more than the cost of the LIBESS. This indicates that the LBESS is more cost-effective than the PSHESS.A Modified Russell Measure for Estimating Efficiency Changes in the Presence of the Undesirable Outputs and Stochastic Data
http://scientiairanica.sharif.edu/article_22564.html
Although data envelopment analysis (DEA) assumes deterministic data, a great volume of data might be stochastic. The global Malmquist productivity index (GMPI) is a highly effective instrument for productivity analysis in DEA. This paper extends GMPI in the presence of stochastic data. Our new stochastic DEA model is a chance-constrained programming model, which is converted to a deterministic programming problem with a linear objective function and quadratic constraints. For efficiency evaluation purposes, in this paper, the weak disposability principle is used to model Russell&rsquo;s measure in the presence of undesirable outputs. The main contribution of this paper is to develop a global Russell model with stochastic data. A case study is presented to illustrate the applicability of the proposed models.Copula-based Modeling for IBNR Claim Loss Reserving
http://scientiairanica.sharif.edu/article_22570.html
There are growing concerns for reserves estimation of incurred but not reported (IBNR) claims in actuarialsciences. In this paper, we propose a copula-based dependency model to capture the relationship betweentwo main IBNR reserve variables, i.e., the &ldquo;time between two successive occurrences&rdquo; and &ldquo;delay time&rdquo;.A maximum likelihood estimation (MLE) method is used to estimate the parameters of the model. Asimulation study is conducted to evaluate the validity of the theoretical results. Moreover, the proposedmethod is applied to predict the number of claims for the next years of a portfolio from a major automobileinsurer and is compared to the classical Chain Ladder model forecasting.Discriminant Analysis-based Parametric Study of an Electrical Discharge Machining Process
http://scientiairanica.sharif.edu/article_22571.html
This paper deals with the application of discriminant analysis in an electrical discharge machining (EDM) process to determine the comparative contribution of each of its input parameters on the measured responses. It also identifies the most significant EDM process parameters influencing those responses. For this process, voltage, current, pulse-on time and pulse-off time are considered as the input parameters, whereas, material removal rate, electrode wear rate and surface roughness are the responses. Based on the past and simulated experimental data, both simultaneous and step-wise estimations are carried out for each of the three responses showing the relationships between the EDM process parameters and the considered responses. It is observed that in both these estimations, pulse-off time, current and pulse-on time respectively evolve out as the most significant parameters for material removal rate, electrode wear rate and surface roughness. Step-wise estimation identifies voltage as the least significant input parameter for all these responses. The developed discriminant functions, which can also help in predicting the responses, are finally cross-validated.An analytical state-space solution for free vibration of sandwich piezoelectric plate with functionally graded core
http://scientiairanica.sharif.edu/article_22572.html
The purpose of this paper is to develop an analytical solution for free vibration analysis of smart functionally graded (FG) plates by the Levy solution in conjunction with the state-space approach. The FG substrate is sandwiched between two piezoelectric layers. The rectangular structure has two simply-supported opposite edges while the boundary conditions of the other two edges are arbitrary. Based on the simple but efficient four-variable refined plate theory, the governing equations are extracted employing Maxwell&rsquo;s equation and Hamilton&rsquo;s principle. The achieved fourth-order partial differential equations are transformed to first-order ordinary ones using the Levy solution along with the state-space approach and then, they are solved by applying the eigenvalue method. Meanwhile, an iterative algorithm is proposed to obtain the natural frequencies of the structure with various boundary conditions. A comparison is made between the obtained results and those available in the literature which verifies the accuracy of the solution method and numerical algorithm proposed in this study. Finally, the effect of several parameters such as type of boundary conditions, aspect ratio, power-law index, piezoelectric layer thickness, and thickness-to-side ratio is examined on the obtained results.UNIT NADARAJAH AND HAGHIGHI DISTRIBUTION: PROPERTIES AND APPLICATIONS IN QUALITY CONTROL
http://scientiairanica.sharif.edu/article_22573.html
This article introduces unit Nadarajah and Haghighi distribution to deal with the inflation of ones. Besides deriving statistical properties of the proposed distribution, several estimation methods are discussed. In particular, maximum likelihood estimation (MLE), least squares estimation (LSE), weighted least squared estimation (WLSE), maximum product spacing (MPS), minimum spacing absolute distance estimation (MSADE), minimum spacing absolute log-distance estimation (MSALDE), Cram\'er-Von-Mises (CVM), Anderson-Darling method (AD) and right-tail Anderson-Darling method (RAD) are considered. Using real data sets, it is shown that the new distribution outperforms some well-known existing distribution. Furthermore, the application of the proposed distribution in quality control is also discussed. A control chart using unit Nadarajah and Haghighi distribution is constructed and its performance is evaluated using the average run length.An Assessment of Data Mining and Bivariate Statistical Methods for Landslide Susceptibility Mapping
http://scientiairanica.sharif.edu/article_22574.html
Landslides are recognized as one of the environmental challenges that lead to land degradation, reduce fertility, and cause significant damage to the ecosystem. Therefore, proper identification of landslide-prone areas through modeling will be significantly helpful for land development managers and planners by providing them with appropriate management strategies to prevent land degradation. In this research, landslide susceptibility mapping was carried out for West Azerbaijan province in Iran using Frequency Ratio (FR), Shannon Entropy (SE), Random Forest (RF), and an ensemble of random forest and bagging (RF-BA) methods. Based on field surveys, local interviews, and review of similar studies, 12 factors influencing landslide occurrence, namely altitude, slope angle, slope aspect, distance from fault, distance from river, distance from road, drainage density, road density, rainfall, soil, land use, and lithology, were identified. In the field surveys, 110 landslides in the area were specified; 70% of the data (77 landslides) were randomly selected and utilized for modeling and the remaining 30% (33 landslides) for validation. The results of the ROC curve showed the accuracy of 0.92, 0.91, 0.89, and 0.88 with the RF-BA, RF, FR, and SE models, respectively.Course timetabling in medical universities given physicians' educational and clinical tasks
http://scientiairanica.sharif.edu/article_22575.html
The physician assignment and course timetabling problem at medical universities is a generalized version of the academic timetabling problem. This problem entails assigning courses, educational and clinical tasks to physician faculty members over a semester or academic year. The problem of timetabling academic courses and scheduling physicians in a hospital has been investigated independently in previous studies in this field. These two fields of research are brought together in this article through the presentation of a multi-objective mixed-integer linear programming (MILP) model. The proposed model is based on two optimization criteria: minimizing workload imbalance and maximizing physician preferences. The model is applied to a case study involving the assignment of physicians to courses, educational and clinical tasks at Kurdistan University of Medical Sciences' Department of Infectious Diseases. Pareto solutions are obtained using an enhanced version of the augmented epsilon constraint implemented in the GAMS optimization software; one is selected as the most desirable solution using the TOPSIS method. The proposed model is generic and could be adapted for use in other departments or medical schools.Study of UV-Vis absorption spectra of magnetic molecule tripyridinium bis[tetrabromidoferrate(III)] bromide with density functional formalisms
http://scientiairanica.sharif.edu/article_22576.html
The UV-Vis absorption spectra of the discrete magnetic molecules [py.H]3[FeBr4]2Br were calculated based on density functional theory with B3LYP exchange-correlation functional in acetonitrile solution. The molecule was dissolved dilutely in acetonitrile to ensure that its experimental response can be attributed to a single dispersed molecule without significant interaction to other molecules. The experimental UV-Vis absorption spectra show four typical peaks in UV region and three peaks in visible region. A number of different basis sets are employed to compare the experimental data with the theoretical absorption spectra on different levels of basis sets. The comparison of experimental data with theoretical computation shows that choosing 6-311++G** improves computational results mainly in visible region and makes little differences between results based on DFT and TDDFT in other wavelength domains, especially in UV wavelengths. The simulated results are of importance in simulating the response of these molecular magnets as a discrete asymmetric unit to applied light.Impact of measurement error on maximum hybrid exponentially weighted moving average control chart
http://scientiairanica.sharif.edu/article_22577.html
Statistical process control provides various types of control charts for monitoring of mean and variance shifts in the industrial production process individually as well as jointly to improve and maintain the quality products. The authors proposed these control charts based on sample values selected to calculate the desired statistics assuming that these values are measured correctly. But in a real life situation, measurements of the values may suffer from errors ultimately affecting the efficiency of the control charts. A few of the researchers in the field of control charts also discussed the problem of measurement error during process monitoring and proposed solutions to avoid losses of producers. We also present a hybrid exponentially weighted moving average control chart for joint monitoring of mean as well as variance and study the effect of measurement error on the efficiency of this control chart and name it as Max-HEWMAME control chart. The impact of measurement error has been shown in the calculations and presented in the shape of average run lengths ( ) and standard deviations of run lengths ( ) using the Monte Carlo simulation method. A real life example is also included to support the simulation results.Computational Exploration of Charge Transfer Dynamics in Dye Sensitized SnO2 and ZnS for Photocatalytic Applications
http://scientiairanica.sharif.edu/article_22578.html
A computational study of some novel charge transfer complexes, prepared by the adsorption of dyes on SnO2 and ZnS was carried out using semiempirical PM3 method. The two natural dyes, 1S,3R,4R,5R-3-(3,4-dihydroxyphenyl)acryloyloxy)-1,4,5-trihydroxycyclohexane carboxylic acid (DTC) and 2-Phenyl-4H-chromen-4-one (PHC) were adsorbed independently on to 1&times;1&times;1 SnO2 and ZnS crystals to form SnO2-DTC, SnO2-DTC-PHC and ZnS-DTC adsorption complexes. The theoretical electronic absorption spectra calculated via PM3 method revealed a large bathochromic shift to 958 nm and 577 nm for SnO2-DTC and SnO2-DTC-PHC, respectively, indicating the formation of charge transfer complex. Moreover, the bandgap was reduced to 1.29 and 2.15 eV as compared to 3.4 eV of pristine SnO2. Subsequently the adsorption of DTC on ZnS was accomplished and calculations were performed to determine the spectroscopic properties of the complex, where a considerable red shift was observed for ZnS-DTC as well. The semiempirical PM3 calculations evidenced stability of SnO2-DTC, SnO-DTC-PHC and ZnS-DTC as predicted from negative adsorption energy values. The positions of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) as obtained from single point energy calculations, were concomitant with proposed photocatalytic mechanisms.The effect of freeze-thaw cycles on mechanical properties of fine grain soil modified by cement and nanocement
http://scientiairanica.sharif.edu/article_22579.html
Freeze-thaw (F-T) cycles cause substantial detriment to geotechnical structures, especially roads, every year. Recently, researchers have increasingly used nanomaterials to improve soil resilience. This study evaluated the effect of soil stabilization by cement and nanocement on resistance changes subjected to F-Tcycles.For this purpose, clayey soil was combined with 1, 2, 3, and 4% stabilizers based on dry unit weight. Atterberg limits and standard compaction tests were performed on the prepared mixtures. The results showedthat increasing the stabilizers enhanced the optimum moisture content, liqid limit, and plastic limitwhile decreasingthe maximum dry density and plastic limit. Then, the cylindrical specimens of the pure and stabilized soilswere prepared and curedwithin 42 days. Finally, unconfined compressive strength(UCS) tests were conducted on the samples after applying zero, three, six, and nineF-T cycles. UCSin the stabilized soil increased to a value about12 times thatin the pure soil. The UCSvalue was reduced on average to 49%inthe pure soil specimens by applying nine F-T cycles, whichfurther decreased on averageto 36% and 31%after adding cement and nanocement, respectively. However, the lowest UCS value was observed in the stabilized soil specimens, reaching 26% and 19%in 42 daysafter applying nineF-T cyclesand adding 4% cement and nanocement, respectively.Multi-period home health care routing and scheduling problem with the medical grouping of patients
http://scientiairanica.sharif.edu/article_22581.html
Home health care service has significant importance in modern societies. In most of the active institutions in this field, the traditional procedure is used for planning and managing health personnel and determining patient visit sequence. This procedure usually causes an increase in costs and reduces patients&rsquo; satisfaction. This paper, for the first time, groups the patients in a model according to the level of emergency and discriminating in their examination. Considering dependency and independence of patient visits to each other, assuming multi-depot and multi-period issues are attractive aspects of the proposed model. The model is solved with GAMS software for small scale and two variable neighborhood search algorithm and simulated annealing algorithm are used to solve large scale problems and their performances are compared. The results indicate minimizing total cost and also increasing patients` satisfaction by the proposed model.Solution of an Economic Production Quantity model using the generalized Hukuhara derivative approach
http://scientiairanica.sharif.edu/article_22582.html
In this study, an economic production quantity (EPQ) model with deterioration is developed where the production rate is stock dependent and the demand rate is unit selling price and stock dependent. The low unit selling price and more stocks correspond high demand but more stock corresponds to slow production because of the avoidance of unnecessary stocks. First of all, we develop the production model by solving some ordinary differential equations having deterministic profit function under some specific assumptions. Later, we develop the fuzzy model by solving the fuzzy differential equations using Generalized Hukuhara derivative. In fact, the differential equation of the model has been split into two parts namely gH(L-R) and gH(R-L) on the basis of left(L) and right(R) &alpha;- cuts of fuzzy numbers for which the problem itself is transformed into multi-objective EPQ problem. A new formula of aggregation of several objective values obtained at different aspiration levels has been discussed to defuzzify the fuzzy multi-objective problems. We solve the crisp and fuzzy models using LINGO software. Numerical and graphical illustrations confirm that the model under Generalized Hukuhara derivative of (R-L) type contributes more profit which is one of the basic novelties of the proposed approach.Comparative modeling of abrasive waterjet machining process based on OA-Taguchi and D-optimal approach and optimization using simulated annealing algorithm
http://scientiairanica.sharif.edu/article_22583.html
In this study a technique has been addressed in order to model and optimize AWJM process. The required data for modeling and optimization purposes has been achieved using orthogonal array Taguchi (OA-Taguchi), D-optimal techniques and their combination based on design of experiments (DOE) approach. Water pressure, abrasive flow rate, machining speed, and machining gap are the process variables considered in this study. To evaluate the process, surface roughness (SR) has been taken into account as the process characteristic. Regression modeling using which has been turned into a widely used method has been employed to establish a relationship between process input variables and output characteristic. Analysis of variance (ANOVA) has been employed to evaluate the adequacy of the proposed models among which the most fitted and proper ones selected as the authentic representative of the process and considered as the process objective function to be optimized. Next, to optimize the objective function in order to get the desired characteristic (SR), the proposed model has been embedded into simulated annealing (SA) algorithm. Based on the computational results (less than 4% error), the proposed procedure is quite effective in modeling and optimization of the process.Reliability-Based Approach for Fragility Analysis of Lattice Transmission Tower in the Type Test
http://scientiairanica.sharif.edu/article_22584.html
Precise prediction of the structural capacity of lattice transmission towers under various loads is essential to assess the reliability of the transmission network accurately. In doing so, the uncertainties inherent in the modeling parameters of the towers need to be taken into account. In this paper, a probabilistic framework is developed to analyze the failure of a 230 kV double-circuit tower in full-scale type test accounting for the uncertainties including eccentricity at the connections, joint slippage, and initial imperfection in the members. Three loading patterns are applied to the manufactured full-scale tension tower. A finite element model of the tower with consideration of mentioned uncertainties is built and verified by the test results. The importance vectors derived from reliability analysis clarifiy the effect of each of these parameters on the target points' displacement, as well as the maximum load carrying capacity in towers' members for these load patterns. Besides, the additional moments due to eccentricity at the connections are considered by a proposed regression-based equation. The failure probability of the tested tower is determined for various load factors, and the results are presented in terms of fragility curves. Besides, the effect of eccentricity on the tower&rsquo;s failure is quantified.Caffeic and Ellagic Acids Simultaneous Spectrofluorometric Analysis by Utilization of Inclusion Complex Formation with γ-Cyclodextrin
http://scientiairanica.sharif.edu/article_22586.html
Fluorescence spectroscopy due to its high sensitivity continues to be of extensive attention to analytical chemists. Spectra recording at several interval times while the reaction is preceded, or at various concentrations of complexing agent, are cases of policies by which one can create second-order data by the spectrofluorometric technique. In this case, fluorescence spectra of a mixture of two caffeic acid (CA) and ellagic acid (EA) target analytes were recorded as a function of &gamma;-cyclodextrin (&gamma;-CD) (as an inclusion complexing agent) concentration to produce second-order data. At this point, bilinear least squares/residual bilinearization (BLLS/RBL), as a second-order calibration technique, due to its benefits of rapidity, accuracy, simplicity, suitable spectral resolution, and concentration estimation even in the presence of the unknown interference (Second-order advantage), was exploited for deconvolution of trilinear data to obtain fluorescence spectra and concentration profiles of the CA and EA as a function of &gamma;-CD concentrations. A calibration set comprising 10 reference samples was employed to build BLLS/RBL model. The resulting model predictive ability was validated by a test set including 6 samples. The suggested model was effectively exploited to simultaneously quantify the content of CA and EA in 4 fruit juice samples.Influenza vaccine supply chain network design during the COVID-19 pandemic considering dynamical demand
http://scientiairanica.sharif.edu/article_22587.html
Nowadays, the healthcare industry focuses on the COVID-19 more than any other issues. There are many close similarities between the symptoms of the coronavirus and the Influenza (flu) virus, which sometimes make it difficult to distinguish between them. So, it has prompted countries to start flu vaccination to prevent potential problems. To consider it, this study presents a multi-level supply chain for the flu vaccine during the COVID-19 pandemic. The problem pursues three main goals: cost minimization, maximizing demand allocation based on customer prioritization, and minimizing maximum lost customer demand. Due to the limited number of vaccines, a rate indicating the priority of each group of customers to receive the vaccine in the proposed model is considered. Customer prioritization can undermine justice because a flu patient is in critical condition but has low priority. Therefore, the third objective seeks to create justice and morality by minimizing the maximum lost demand. To evaluate the model, it is conducted based on a case study in Mazandaran province, Iran. The findings illuminate that 79 % of the demand will be met. Besides it shows that by increasing the capacity to 10%, the demand will be satisfied 9 percent more.A possibilistic programming approach for biomass supply chain network design under hesitant fuzzy membership function estimation
http://scientiairanica.sharif.edu/article_22588.html
The recognition of membership function by knowledge acquisition from experts is an important factor for many fuzzy mathematical programming models. Thus, the hesitant fuzzy membership function (HFMF) estimation could help users of the mathematical programming approaches to provide a powerful solution in continuous space problems. Therefore, this study proposes a possibilistic programming approach based on Bezier curve mechanism for estimating the HFMF. In the process of possibilistic programming approach, an optimization model is presented to tune the primary parameters of Bezier curve by the goal of minimizing the sum of the squared errors (SSE) between the empirical data and fitted HFMF. After that, the efficiency and applicability of the proposed approach is checked by proposing a novel mathematical model for biomass supply chain network design problem. In this case, the bio-products demand is declared as an imprecise parameter that follows from the estimated HFMF to increase the accuracy of the obtained results by addressing the uncertainty and unreliability of the information. Finally, a computational experiment and validation procedure about the biomass supply chain network design is provided to peruse the verification and validation of the proposed approaches.Identifying Damage Location under Statistical Pattern Recognition by New Feature Extraction and Feature Analysis Methods
http://scientiairanica.sharif.edu/article_22589.html
Vibration data analysis is an applicable approach to Structural Health Monitoring (SHM) using statistical pattern recognition. The objective of the paper is to identify the location of damage by a new feature extraction technique and propose some feature analysis tools as statistical distance measures. The proposed algorithm of feature extraction relies on a combination of the well-known Principal Component Analysis (PCA) and a convolution strategy. After extracting the features from raw vibration signals of undamaged and damaged conditions, those are applied to the proposed feature analysis approaches called the coefficient of variation, Fisher criterion, Fano factor formulated by using the features extracted from the PCA-convolution algorithm. To localize damage, the sensor location with the distance value exceeded from a threshold limit is identified as the damaged area. The main innovations of this research are to present a new hybrid technique of feature extraction suitable for SHM applications and four effective statistical measures for feature analysis and damage identification. The performance and reliability of the proposed methods are verified by a four-story building model and a benchmark beam. Results demonstrate that the approaches presented here can influentially identify the location of damage by using the features extracted from the proposed PCA.Thermo-fluid performance evaluation of a split-winglet supported elliptical tube type Fin-and-tube heat transfer surface
http://scientiairanica.sharif.edu/article_22590.html
Vortex generator supported Fin-tube heat transfer surface having inline elliptical tubes is investigated by performing numerical simulations governed by finite volume method. The present investigation is aimed at minimizing the air-side thermal resistance by utilizing the rectangular winglet pairs. The thermo-fluid performance of the baseline model is investigated for the circular and elliptical tube configurations. It is found that the former resulted in higher heat transfer whereas the latter reduces the pressure drop. The effect of split winglet pair&rsquo;s span-wise and stream-wise separation, and attack angle on heat transfer and pressure drop performance is examined in detail and the results were presented in terms of Nu, f and &eta;. Optimum stream wise and span wise locations for the front and rear winglet pair were identified based on highest enhancement factor. It is also found that the optimum attack angle of the front and rear winglet pair is different for maximum enhancement factor.Design of circularly polarized irregular octagonal shaped and dumbbell slotted planar and conformal patch antenna
http://scientiairanica.sharif.edu/article_22591.html
High gains with highly efficient circularly polarized (CP) microstrip planar and conformal cylindrical patch antenna are designed for ISM band. Dumbbell shaped slot is incorporated at the centre of an irregular hexagonal radiator for the production of circular polarisation with high gain. The simulated results indicate impedance mismatch loss (S11) bandwidth of 78.8 MHz and an axial ratio bandwidth (AR) of 10.3 MHz for planar patch. However the impedance mismatch loss bandwidth and AR bandwidth comes out to be 46.2 MHz and 10.6 MHz for conformal cylindrical patch antenna respectively which shows that return loss bandwidth is dropped down by almost 42% for the case of conformal cylindrical antenna and axial ratio bandwidth remains almost similar. Axial Ratio beam-width for Phi = 0 degree are 83 degree and 61 degree for planar patch and conformal patch respectively. Consequently, the gain obtained in planar patch is 8.79 dBic with the efficiency of 96.33% and in the case of conformal patch, the gain comes out to be 4.16 dBic with an efficiency of 95 %.Effect of Hydrochloric Acid Corrosion and CFRP Coating on the Buckling Behavior of Cylindrical Shells Under External Pressure
http://scientiairanica.sharif.edu/article_22592.html
Thin walled cylindrical shells are being widely used as silos, liquid tanks, marine structures, and industrial chemical plants. In such applications, the shells are mostly exposed to liquids. When shells filled with low-pH-liquids, corrosion occurs at the surface. Corroded material loss, causes the thickness of the shells to decrease, and it reduces the buckling capacity of shells. The purpose of this study is to investigate the effects of corrosion on the buckling capacity of thin walled cylindrical shells subjected to uniform external pressure. The model shells were half or full filled with 5% and 10% HCl (Hydrochloric Acid) solutions for corrosion. To tolerate the negative effects of corrosion, the cylinders were coated with varying sizes of CFRP sheet. Totally 12 models were investigated throughout this research, with the dimensions of 800x400x0.45 mm (with and without CFRP). The perfect non-corroded models were used to compare the behavior of all the models. Results show that corrosion causes a significant decrease on the buckling capacity of thin walled cylindrical shells. Acid ratio, filling rate and surface area coated with CFRP fabrics affects the buckling capacity of cylinders. Coating the cylinders with one layer of CFRP resulted with tolerating the buckling capacity loss.A frequency and polarization reconfigurable L shaped patch antenna with defected ground structure
http://scientiairanica.sharif.edu/article_22593.html
A novel geometry of polarization and frequency reconfigurable antenna is proposed in this paper. Proposed antenna consists of an L shaped patch antenna, where arms are separated using PIN-diode. Two parasitic elements, shorted back element and edge tapered defected ground structure with slot are used for achieving wide impedance and axial ratio bandwidth. It acts as circular polarized antenna with 1.183 GHz axial ratio band width and 3.09 GHz impedance bandwidth in ON state of both diodes and act as linear polarized frequency reconfigurable antenna at remaining states of diodes. Proposed antenna can be used in C band wireless applications like RADAR, satellite communication etc.Sensitivity analysis for Walters' B nanoliquid flow over a radiative Riga surface by RSM
http://scientiairanica.sharif.edu/article_22594.html
In this examination, a sensitivity analysis is implemented using response surface strategies to control the Walters-B nanofluid stagnant point flow caused by a Riga surface. An electromagnetic actuator is known as Riga-surface. The Buongiorno model is used to construct the mathematical model, which includes a Newtonian heating condition as well as radiation effects. Via the fundamental laws of mass, momentum, and energy, transformation is incorporated to obtain nonlinear ordinary differential equations. To solve the governing system, the numerical shooting approach along with Runge-Kutta scheme is used to solve the governing system. A comparison with existing research is made, and the results are obtained to be in strong agreement. Focusing on the response of local Nusselt number to variation of input variables, an experimental structure is incorporated by sensitivity analysis. As underline, the LNN is quite sensitive to radiation number rather than other parameters of interest. Meanwhile, it is demonstrated that sensitivity of LNN to Brownian number decreases with growing thermophoresis number but sensitivity value is also vary from positive to negative for all values of Brownian number. The results are assumed to provide a tentative guidance for possible lab-based experiments.A Non-Convex Robust Simulation Optimization Model for Inventory Management Problem by System Dynamics
http://scientiairanica.sharif.edu/article_22595.html
Perishable product inventory management is a challenging issue because of its direct effect on companies' profits. The dependence of a product order cost on the order quantity is one of the practical but less examined assumptions in this problem literature. Hence, this paper considers the dependency between the order cost and order quantity as well as between the holding cost and the inventory level. This problem will have a non-convex object, and is not solvable through the usual mathematical methods. Thus, simulation-optimization approach is used to determine the perishable product inventory management policy with stochastic demand. The system dynamics approaches have been used to simulate the problem by minimizing the cost function. The casual diagram, inputs, output, and relation of the system are determined. A numerical example of a hypermarket is presented, and the optimal amount of the objective function is determined with optimization of the input variables via the experimental design&rsquo;s method. Then, to rule out the effects of different errors, a robust optimization of the model is presented. The results show that the proposed replenishment policy could benefit the necessary decisions regarding inventory management and control of the perishable products which count in different errors.Dynamic modeling and optimal control of stone-carving robotic manipulators
http://scientiairanica.sharif.edu/article_22612.html
The stone-carving robotic manipulators (SCRM) find a broad range of applications due to their high efficiency, wide range of processing and strong flexibility. However, the features of strong disturbance, uncertainty and variation in the parameters make the design of SCRM control systems more complicated. This paper introduced the inverse linear quadratic (ILQ) theory into the SCRM control system. First, we deduced the dynamic equation and state-space equation of the SCRM system with the Lagrange method. Then, the ILQ theory was used to achieve the desired closed-loop poles assignment of the system. To simplify the design process and meet the requirement of practical use, the state feedback optimal control law was determined by an improved ILQ design method. The proposed control scheme has the explicit capacity to achieve the desired joint angle and joint torque control performances, with fewer external disturbances and no sensitivity to changing model parameters. The effectiveness of the proposed control scheme compared with the traditional control strategies is shown in the simulation results. Thus, the vibration of the joint torque during the manufacturing process can be greatly reduced.Modeling and detection of demagnetization fault in permanent magnet vernier machine using flexible magnetic equivalent circuit method
http://scientiairanica.sharif.edu/article_22613.html
In this paper, an analytical model is proposed for evaluating electromagnetic performances of permanent magnet vernier machines (PMVMs) under healthy and faulty conditions. The proposed model employs flexible magnetic equivalent circuit (MEC) method, which its accuracy can be selected by tunable parameters. The model is capable of considering the influence of saturation effect, skewed slots, slot leakage fluxes, and various winding arrangements for the machines with desired properties. First, the proposed model is used to predict the no-load performance of machine at healthy condition. Then, the machine loading behaviors under healthy and demagnetization fault conditions are analyzed by the MEC model. Moreover, the results of the proposed model are compared and validated with those of 2-D finite element method (FEM) and 3-D FEM. Eventually, a specific pattern is extracted from the stator current spectrum to detect the demagnetization fault.Product Acceptance Determination Based on EWMA Yield Index Using Repetitive and MDS Sampling Schemes
http://scientiairanica.sharif.edu/article_22623.html
In this manuscript, we present a repetitive group sampling plan and a multiple dependent state sampling plan based on the EWMA (exponentially weighted moving average) yield index for product acceptance. The proposed plans utilize the current and the previous information through EWMA statistic to reach a decision of lot sentencing. A non-linear optimization model is developed to determine the plan parameters of the proposed plans for various specified conditions. The performance of the proposed plans over several existing sampling plans is analyzed, which shows that the proposed plans are efficient in reducing the sample size for lot sentencing. For industrial application, a real example is given to demonstrate the implementation of the proposed plans.Experimental Study of Effect of Laser Machining Process of CO2 on Electrical Conductivity and Magnetic Properties of PMMA/MWCNT Composite
http://scientiairanica.sharif.edu/article_22624.html
The present work aims to investigate the effect of the parameters of the laser machining process and laser line angle to injection direction of sample plastics on the electrical resistance of Polymethyl Methyl Methacrylate (PMMA)/Multi-Wall Carbon Nanotubes (MWCNT) Nano-composite. The laser machining process was performed on the samples considering a combination of power, feed rate, and laser line angle with respect to to the direction of melted flow parameters. According to the obtained results from electrical resistance and magnetic properties measurements, this was demonstrated that the laser line angle to the direction of melted flow does not statistically, and physically affect the electrical resistance of the composite. And increasing laser machining power leads to electrical resistance reduction. On another hand, feed rate enhancement (with fixed lasering power) causes increasing the electrical resistance. Moreover, this is found out that laser machining does not significantly affect the magnetic properties of the samples.Developing a multiproduct three-level cold supply chain considering quality evaluation function and pricing mechanism
http://scientiairanica.sharif.edu/article_22625.html
Paying attention to cold supply chains is critical in light of rising global warming and public awareness of the issue. In addition, a lack of appropriate quality control in supply chains has resulted in significant waste in the industry. This research sought to create a three-level cold supply chain (firm, distribution center, and retailer) with a quality evaluation function. The chain has been modelled for a multiplicity of products and time periods. The parameters in this model are analyzed in three separate scenarios to reflect uncertainty. The model also includes direct delivery from the firm to the store. Various factors can affect the quality evaluation variables, which in this model are assigned to two main parameters: temperature and humidity. The quality of the products in this model is used to estimate their selling price. Due to the nonlinearity of the model, the Baron approach is applied in this work.Investigation of Operational Parameters on the Separation Factor of Praseodymium and Neodymium from model NdFeB Magnet-leaching Solution in the Solvent Extraction: Optimization by Response Surface Methodology
http://scientiairanica.sharif.edu/article_22626.html
In this study, the separations of praseodymium (Pr) and neodymium (Nd) from model NdFeB Magnet-leaching solution were evaluated by two different mixtures, namely Aliquat 336/toluene (system I) and Cyanex 272/kerosene (system II). The operational parameters such as Aliquat 336 concentration (0.30-0.85 mol/L), Cyanex 272 concentration (0.23-0.57 mol/L), pH (2.0-5.0), organic to aqueous phase (O/A) ratio (1-3), and ammonium nitrate (AN) concentration (2.2-5.6 mol/L) were investigated. The impact of the studied parameters on the separation factor were modeled, compared, and optimized by response surface methodology (RSM) based on the central composite design (CCD). The parameters had relatively consistent impact on the extraction efficiency and selectivity of the system I but inconsistent impact for the system II. According to the optimization results of the operational selectivity, the system I was more fitted in which the extraction efficiencies of Pr and Nd were obtained 74.8% and 61.2%, respectively, and the separation factor was 2.10. The obtained values for Aliquat 336 concentration, O/A ratio, pH, and AN concentration were 0.85 mol/L, 1, 5.0, 3.9 mol/L, respectively. Finally, the stripping of metal ions from the loaded organic phase was effectively conducted with 0.1 M hydrochloric acid solution within a contact time of 5 minutes.A Modified Metaheuristic Algorithm Integrated ELM model for Cancer Classification
http://scientiairanica.sharif.edu/article_22627.html
Background: In the rapidly defiled environment, cancer has emerged out as the most threatening disease to human species. Therefore, a robust classification model is required to diagnose cancer with high accuracy and less computational complexity.Method: Here, random parameters of Extreme Learning Machine (ELM) are optimized by Self Adaptive Multi-Population-based Elite strategy Jaya (SAMPEJ) algorithm. This strategy constructs a robust ELM classiﬁer named as SAMPEJ-ELM model. This model is tested on Breast cancer, Cervical cancer and Lung cancer datasets. Here, a comparative analysis is presented between the proposed model and basic ELM, Jaya optimized ELM (Jaya-ELM), Teaching Learning Based Optimization (TLBO) optimized ELM (TLBO-ELM), SAMPEJ optimized Neural Network (SAMPEJ-NN), SAMPEJ optimized Functional Link Artificial Neural Network (SAMPEJ-FLANN) models. Numerous performance metrices viz. accuracy, speciﬁcity, Gmean, sensitivity, F-score with receiver operating characteristic (ROC) curve are used to estimate the proposed model. Moreover, this model is compared with eleven existing models.Results: SAMPEJ-ELM model resulted the highest degree of accuracy, sensitivity and specificity in Breast Cancer (.9895, 1, .9853), Cervical Cancer (.9822, .9948, .9828), Lung cancer (.9787, 1, 1) datasets. Conclusion: The experimental results reveal that SAMPEJ-ELM model classifies both the positive and negative samples of cancer datasets significantly better than others.A Variable Sampling Interval Multivariate Exponentially Weighted Moving Average Control Chart for Monitoring the Gumbel’s Bivariate Exponential Data
http://scientiairanica.sharif.edu/article_22628.html
The general assumption for designing a multivariate control chart is that the multiple variables are independent and normally distributed. This assumption may not be tenable in many practical situations, because multiple variables with dependency often need to be monitored simultaneously to ensure the process is in-control. The Gumbel&rsquo;s Bivariate Exponential (GBE) distribution is considered a better model for skewed data with dependency in reliability analysis. In this paper, a Multivariate Exponentially Weighted Moving Average (MEWMA) control chart with Variable Sampling Interval (VSI) feature is developed to monitor the mean vector of GBE model. Monte-Carlo simulations are used to calculate the ATS (Average Time to Signal) values of the proposed VSI MEWMA GBE chart for three different types of shifts. Meanwhile, some tables are provided to show the ATS performances of the proposed chart with different designed parameters. Furthermore, both zero- and steady-state ATS performances of the proposed VSI MEWMA GBE chart are compared with those of the FSI (Fix Sampling Interval) MEWMA chart. Comparative results show that the proposed chart is superior to its FSI counterpart in monitoring the GBE data. In addition, a numerical example is provided to show that the proposed chart performs well in monitoring GBE data.A new class of robust ratio estimators for finite population variance
http://scientiairanica.sharif.edu/article_22629.html
It is a general practice to use robust estimates to improve ratio estimators using functions of the parameters of an auxiliary variable. In this study, a new class of robust estimators based upon the minimum covariance determinant (MCD) and the minimum volume ellipsoid (MVE) robust covariance estimates have been suggested for estimating population variance in the presence of outlier values in the data set for the simple random sampling. The expression for the mean square error (MSE) of the proposed class of estimators is derived from the first degree of approximation. The efficiency of the proposed class of robust estimators is compared with some competing estimators discussed in the literature and found that proposed estimators are better than other mentioned estimators here. In addition, real data set and simulation studies are performed to present the efficiencies of the estimators. We demonstrate theoretically and numerically that the proposed class of estimators performs better than all other competitor estimators under all situations.Failure Analysis of the 16-Story Plasco Building under Fire Condition
http://scientiairanica.sharif.edu/article_22630.html
The progressive collapse of the 16-story Plasco steel building induced by fire in Tehran on 19 January 2017 led to the death of dozens of firefighters. This paper presents the results of a comprehensive 3D nonlinear finite element analysis of a floor of the Plasco building under fire condition. The LS-DYNA program is used to investigate the cause of steel beam-to-column connection failure. Results of the nonlinear analysis of detailed numerical model confirms the failure modes of the structural elements such as columns, trusses, joists, beams, welds, and other structural elements investigated during the site visits. Design recommendations are provided based on the results from the fire analysis of the Plasco building.Effect of insertion process on biceps tendon reconstruction in BASHTI technique; an in-vitro study
http://scientiairanica.sharif.edu/article_22631.html
BASHTI implant-less technique has been proposed as an alternative to conventional tendon repair methods. This study aims to evaluate the strength of this technique under biceps loading conditions with different fixation strategies. Twelve specimens with bovine tendons and Sawbones were constructed using two different insertion methods; in Group 1, 4 samples were prepared using a hand-hammer with a hitting frequency of 300 beats per minute (BPM), while Group 2 included eight specimens with insertion using an auto-hammer applying a frequency of 3600 BPM. Both groups were tested under a cyclic loading followed by a pull-out until the failure. All the samples completed the cyclic step without failure. At the pull-out step, for Group 1, the strength was 251&plusmn;31 N, and the stiffness was 10.3&plusmn;0.8 N/mm, while these values were 183&plusmn;35 N and 10.5&plusmn;3.0 N/mm, respectively for Group 2. It was concluded that the BASHTI structure for biceps tendon reconstruction had a suitable strength and the insertion process had no effect on its behavior under cyclic loading. It was also proved that variations in the insertion frequency significantly affect the structure's maximum strength (p-value = 0.038). Still, its influence on the stiffness was insignificant (p-value = 0.91).Multi-objective low-carbon hybrid flow shop scheduling via an improved teaching-learning-based optimization algorithm
http://scientiairanica.sharif.edu/article_22632.html
In this article, for achieving an effective and environmental-friendly production scheduling, we investigate a multi-objective low-carbon hybrid flow shop scheduling problem (MLHFSP) with the consideration of machines with varied energy usage ratios. The problem is formulated by a multi-objective mathematical model with two optimization objectives, i.e., minimizing total carbon emission (TCE) and makespan (Cmax). We primarily analyse on the formation of TCE and derive its mathematical expression. MLHFSP is NP-hard, therefore, to tackle the model, an improved multi-objective teaching-learning-based optimization (ITLBO) algorithm is proposed. The ITLBO algorithm mainly contains global search based teaching phase and local search based learning phase. In ITLBO, a solution is represented by two vectors, i.e., job sequence vector and machine assignment vector. Sigma method is utilized to quantify each individual, and to avoid local optimum, sequential neighbourhood search (SNS) method is also adopted. Experimental results validate the feasibility and effectiveness of proposed ITLBO in addressing MLHFSP. The research findings help manufacturing engineers to seek a sophisticated balance between carbon emission reduction and makespan reduction.Estimation of earthquake frequency content and its effect on dynamic analysis using continuous and discrete wavelet transform
http://scientiairanica.sharif.edu/article_22635.html
In this paper, for the first time, the combination of these two concepts is used for the earthquake acceleration wave. For this purpose, eight earthquakes from four different locations in the world have been selected. Initially, each earthquake is filtered up to 5 stages using a discrete wavelet transform. Due to the close approximation of the frequency content of the wave to the original earthquake, the approximate wave is used for subsequent calculations. In the next stage, the spectrum of Fourier and the diagram of five of the frequency of dominant of the earthquake are plotted. Also, using the continuous wavelet transform, the time-frequency curves of the main earthquakes and the time-frequency curves of the wave obtained from the discrete wavelet transform are investigated. The goal is to find the best stage of a discrete wavelet filter based on frequency content to reduce computations to over 80%. In the next step, the study examines the time of the strong ground motion, the structure response of single degree of freedom, and the dynamical response of the timing of the structure of a degree of freedom. By examining the above parameters, the best-performing wavelet transformation step is inferred.Evaluation of the reliability of the deregulated radially distribution network with consideration of vehicle to grid
http://scientiairanica.sharif.edu/article_22636.html
The essential reduction of fossil fuels and environmental pollutants has caused Electric Vehicles (EVs) to be considered. EVs are able to participate as a manufacturer in the electricity market through Vehicle to Grid (V2G) technology. This greatly improves the reliability of distribution systems. Therefore, it is necessary to plan the charging and discharging process in the parking lot. This paper has firstly investigated the different strategies for planning the charging and discharging process of EVs considering the random and unpredictable nature of various parameters, and also the limitation of the power exchange between the distribution system and parking, to evaluate the impact of V2G-equipped parking spaces on reliability. An appropriate strategy is the strategy that will increase the owner's interest in the parking lot. The results show that the use of V2G and charge-discharge strategies improve reliability (SAIFI, SAIDI, ASAI and ENS indices) of the distribution system. By examining the results of each of the strategies, the proposed strategies are able to increase parking revenue by an average of 21.6% and improve reliability indices of the distribution network up to 8.8%.Investigating non-Newtonian nano-fluid flow based on first and second law of thermodynamics by micro-annulus
http://scientiairanica.sharif.edu/article_22638.html
In this study first and second law analyses of non-Newtonian nano-fluid flow through an annular cylinder filled with non-Newtonian water- CMC/TiO2 nano-fluid by considering temperature jump and slip velocity were investigated numerically. The single-phase was developed for heat transfer and nano-fluid flow. The impact of Reynolds number, nano-particles volume fraction, temperature jump, and slip velocity on Nusselt numbers and entropy generation were evaluated and the findings were discussed considering non-Newtonian performance of working fluid. The findings indicate that note the higher shear rate in the presence of the interior wall the Nusselt number for the interior wall was higher than outside walls. According to shear-thinning fluid behavior, when the flow has a higher shear rate, apparent viscosity would be small. So, it can be concluded that the apparent viscosity of flow close to the inner wall was low which decreased the impact of viscosity force and improved heat transfer due to convection-advection phenomena. In addition, the findings showed that the entropy generation ratio is very high at the entrance and it decreased along the annular tube. Furthermore, the apparent viscosity of fluid increases by nano-particle volume fraction.Developing a two-stage multi-period stochastic model for asset and liability management: A real case study in a commercial bank of Iran
http://scientiairanica.sharif.edu/article_22639.html
In this paper, a novel two-stage multi-period stochastic model is developed to obtain a comprehensive plan. This plan aims to manage the assets and liabilities such that all legal and budget constraints are satisfied. Assets in the model include short- and long-term loans with reasonable interest rates, investments in the stock market, varied bonds with different expirations, investments in other banks, and the legal budget in the Central Bank. However, liabilities encompass all types of sight and investment deposits with different maturities. In the model, each type of deposit's amount is considered a decision variable, while its total amount is assumed to be stochastic. The mathematical model is constructed in an innovative way such that all previous loans and bonds with possible transactions in the planning horizon could be considered initial parameters. Real data for a commercial bank in Tehran, the Islamic Republic of Iran capital, are used to construct and check the optimization model. The total revenues obtained through the mathematical model and one achieved based on the experiences of financial experts in the commercial bank for four years are compared.Inventory control and price discount policies for perishable products with age and price-dependent demand
http://scientiairanica.sharif.edu/article_22640.html
In this paper, the inventory control and price discount problem for perishable products with price and age-dependent demand is investigated. The seller adjusts prices to influence demand and optimize profits through determining discount points, especially discount start time. A nonlinear mathematical model is proposed to find optimal order quantity, discount points, and prices before the product's expiration date to maximize profit. The developed model provides the number of discounts such that the shortage will not be allowed before the expiration date. It is observed that determining a proper discount start time provides an optimized sales plan with higher profit. Moreover, the particle swarm optimization (PSO) and the genetic algorithm (GA) are applied to solve the problem. The Taguchi approach is used to find optimum control parameters of PSO and GA. To guarantee the validity of PSO and GA, the nonlinear model is solved by the BARON solver in GAMS software. The performance of the algorithms is evaluated based on the real values of parameters for two perishable products (i.e. Cheese and Mayonnaise Sauce) and some random test problems. The computational results demonstrate that the proposed GA outperforms the PSO algorithm.Simulation optimization approach for dynamic and stochastic closed loop supply chain network
http://scientiairanica.sharif.edu/article_22641.html
In this paper, four simulation optimization (SO) models are developed by combining simulation and genetic algorithm. In proposed models, optimal values of inventory control parameters and the number of facilities to be opened are determined simultaneously for periodic review and continuous review systems, respectively. Furthermore, single product and multi-components of closed-loop supply chain (CLSC) network are created considering two different objective functions of review systems to gain a sustainable competitive advantage for companies. We seek to offer valuable insights for creating robust and user-friendly CLSC network where the forward network includes suppliers, plants, retailers, and customers, and reverse network includes collection centers, disassembly centers, refurbishing centers, and disposal center. The results of this study demonstrated that four SO models have a significant potential to satisfy the customer&rsquo;s needs since average service level of the models is at least 81.8%. The total supply chain cost can be decreased at least 3% and at most 22% on average with proposed continuous review model whose objective is the minimization of differences between the total overordering cost and the total underordering cost (C-D). Furthermore, the total lost sales cost can be improved at least 15% and at most 89% on average with C-D model.