Sharif University of TechnologyScientia Iranica1026-309829120220201Modified tumor diagnosis by classification and use of canonical correlation and support vector machines methods1211342253610.24200/sci.2021.56370.4694ENH. Samadi GhoshchiFaculty of Electrical Engineering, Urmia University of Technology, Urmia, IranY. PourasadFaculty of Electrical Engineering, Urmia University of Technology, Urmia, IranJournal Article20200708The 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.https://scientiairanica.sharif.edu/article_22536_fbb09292c9ef7f64e683c9ab903daaf5.pdfSharif University of TechnologyScientia Iranica1026-309829120220201Reliability evaluation of software architectural styles based on correlated component failure1351492253710.24200/sci.2021.56444.4726ENS. EmadiDepartment of Computer Engineering, Yazd Branch, Islamic Azad University, Yazd, Iran0000-0001-8387-3904Journal Article20200718The aim of this study is to provide an efficient and scalable way to evaluate the reliability of different software ar-chitectural styles with regard to correlated components failures. In this way, a method 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 such that it can be used for large software architectures with heterogeneous and homogeneous styles. The results of the evaluation on the case study show that this method is more accurate than the other methods for reliability prediction of the software architectures. As a result, it is concluded that the proposed method is suitable for the preliminary estimation of the software architecture reliability and can make a better comparison between various architectural styles to choose the best and most suitable one from the available options.https://scientiairanica.sharif.edu/article_22537_3b275db25f5d811066e64c1a352a1f81.pdfSharif University of TechnologyScientia Iranica1026-309829120220201A comparative analysis of the new excitation controlled synchronous generator-based wind turbine1511672155910.24200/sci.2019.51354.2132ENA. ShamsniaDepartment of Electrical Engineering, Sharif University of Technology, Tehran, Iran0000-0002-5005-8660M. ParnianiDepartment of Electrical Engineering, Sharif University of Technology, Tehran, Iran0000-0002-2224-9953Journal Article20180703Excitation 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.https://scientiairanica.sharif.edu/article_21559_f5f56385febba0d52b7d9a560d70fbc4.pdfSharif University of TechnologyScientia Iranica1026-309829120220201Polygonal tubular linear permanent magnet generator analysis and experimental test1681822153910.24200/sci.2019.50094.2739ENS. ArslanDepartment of Electrical, Organized Industrial Zone Vocational High School, Harran University, Sanliurfa, Turkey0000-0002-1187-5633O. GurdalGazi University, Faculty of Technology, Department of Electrical and Electronic Engineering, Ankara, TurkeyJournal Article20181219Free 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.https://scientiairanica.sharif.edu/article_21539_5524639ea2e60fa59cb320e0764b6f63.pdfSharif University of TechnologyScientia Iranica1026-309829120220201Designing and analyzing two non-invasive current sensors using Ampere's force law1831922167010.24200/sci.2019.52725.2858ENM. R. Zamani KouhpanjiDepartment of Electrical and Computer Engineering, University of Minnesota Twin Cities, Minneapolis, MN 55455, USA0000-0002-3042-9997Journal Article20190118Here 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.https://scientiairanica.sharif.edu/article_21670_e7b4c5d2fdfb63e39cb91aa0f67836c3.pdfSharif University of TechnologyScientia Iranica1026-309829120220201Control and stability analysis of VSC-HVDC based transmission system connected to offshore wind farm1932072155610.24200/sci.2019.52980.2984ENA. HaghiDepartment of Electrical and Computer Engineering, University of Kashan, Kashan, P.O. Box 87317-53153, IranM. RahimiDepartment of Electrical and Computer Engineering, University of Kashan, Kashan, P.O. Box 87317-53153, IranJournal Article20190219Offshore 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.https://scientiairanica.sharif.edu/article_21556_08e9f774bfb179a0f0003b55eb683bdc.pdfSharif University of TechnologyScientia Iranica1026-309829120220201A dual-stator machine with diametrically magnetized PM: Analytical air-gap flux calculation, efficiency optimization, and comparison with conventional dual-stator machines2082162154510.24200/sci.2019.53316.3181ENSh. AsgariLaboratory of Electrical Machines and Transformers Research, Department of Electrical Engineering, Amirkabir University of Technology, Tehran, P.O. Box 1591634311, Iran0000-0003-3541-9859R. YazdanpanahDepartment of Electrical Engineering, University of Larestan, Lar, Iran0000-0003-2528-3062M. MirsalimLaboratory of Electrical Machines and Transformers Research, Department of Electrical Engineering, Amirkabir University of Technology, Tehran, P.O. Box 1591634311, IranJournal Article20190412This 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.https://scientiairanica.sharif.edu/article_21545_d910ee779bb82aace83a254c42fc14a3.pdfSharif University of TechnologyScientia Iranica1026-309829120220201Design and optimization of a large-scale permanent magnet synchronous generator2172292156110.24200/sci.2019.53569.3314ENMehdi Alemi-RostamiDepartment of Electrical Engineering, Aerospace Research Institute (ARI) of Ministry of Science, Research and Technology,Tehran, IranG. RezazadehDepartment of Electrical Engineering, Sharif University of Technology, Tehran, IranR. Alipour-SarabiDepartment of Electrical Engineering, Sharif University of Technology, Tehran, Iran0000-0002-4066-1132F. TahamiDepartment of Electrical Engineering, Sharif University of Technology, Tehran, Iran0000-0002-9729-7263Journal Article20190516Direct 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.https://scientiairanica.sharif.edu/article_21561_01e8e41fddba7d13d467f0e8abcae482.pdfSharif University of TechnologyScientia Iranica1026-309829120220201An incentive-based policy on minimization of GHG emissions and loss using adaptive group search multi-objective optimization algorithm2302462154610.24200/sci.2019.53554.3326ENM. H. NazariDepartment of Electrical Engineering, Amirkabir University of Technology, Tehran, IranS. H. HosseinianDepartment of Electrical Engineering, Amirkabir University of Technology, Tehran, IranE. Azad FarsaniDepartment of Electrical Engineering, Golpaygan University, Golpaygan, IranD. FaramarziDepartment of Electrical Engineering, Amirkabir University of Technology, Tehran, IranJournal Article20190609A 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.https://scientiairanica.sharif.edu/article_21546_cd9edffd2c8bdbbcf9d0c7b8a49d2a40.pdf