2018-06-21T03:12:33Z
http://scientiairanica.sharif.edu/?_action=export&rf=summon&issue=299
Scientia Iranica
Scientia Iranica
1026-3098
1026-3098
2014
21
3
A hybrid meta-heuristic for balancing and scheduling assembly lines with sequence-independent Setup times by considering deterioration tasks and learning effect
N.
Hamta
S.M.T.
Fatemi Ghomi
R.
Tavakkoli-Moghaddam
F.
Jolai
This paper addresses the Simple Assembly Line Balancing Problem of type II (SALBP-II), with Simultaneous eects of deterioration and learning in which there are sequence-independent setup times relating to each task. In many real industrial environments, although the actual task processing times are dened as a function of their starting times due to deterioration eects, workstations improve continuously as a result of repeating the same activities by worker(s) or machine(s). In this paper, a mathematical model is developed for this novel problem, attempting to minimize the cycle time for a given number of workstations. In addition to the balancing of the assembly line, the developed model presents the execution scheduling of tasks assigned to each workstation. Moreover, a hybrid meta-heuristic method is proposed to solve such an NP-hard problem. This robust and simply structured solution approach uses the tabu search within the Variable Neighbourhood Search (VNS/TS). The computational experiments and comparison with a Dierential Evolution Algorithm (DEA) re ect the high eciency of our proposed algorithm for a number of well-known instances.
Assembly line balancing
Scheduling
Deterioration tasks
Learning eect
Hybrid meta-heuristic
Sequence-independent setup times
2014
06
01
963
979
http://scientiairanica.sharif.edu/article_3534_b9da64736a2a839971d2db8e4d10394e.pdf
Scientia Iranica
Scientia Iranica
1026-3098
1026-3098
2014
21
3
Scaling implementation of the tension rectification algorithm to solve the feasible differential problem 888
Mehdi
Ghiyasvand
The feasible differential problem is solved using the tension rectification algorithm. In this paper, we present a scaling mplementation of the tension rectification algorithm. Let n, m,U denote the number of nodes, number of arcs, and maximum arc capacity value of an arc, respectively. Our implementation runs in O(mnlog U), which is O(mnlog n) under the similarity assumption. The tension rectification algorithm runs in O(m2) time, so our implementation is an improvement if n log n
Operations research
Network flows
The feasible differential problem
Tension rectification algorithm
Scaling implementation
2014
06
01
980
987
http://scientiairanica.sharif.edu/article_3535_a079115df1e28fe05023b6a701bbd07b.pdf
Scientia Iranica
Scientia Iranica
1026-3098
1026-3098
2014
21
3
Network design of a decentralized distribution supply chain: Analysis of non-cooperative equilibrium vs. coordination with discount or buyback mechanism
Ashkan
Hafezalkotob
Ahmad
Makui
This paper develops a model for illustrating how a manufacturer can use his initiative to organize the retailers when they take decisions as independent actors. The candidate retailers are able to distribute product over geographical dispersed markets with stochastic demands. Each manufacturer’s decision about selecting a set of retailers results in a unique distribution network design. Taking transportation and inventory costs into account, each candidate retailer determines order quantity to satisfy markets’ demands, while the manufacturer specifies wholesale price pursuing uniform or retailer-specific pricing polices depending on trade legislations. In this single period problem and under mild assumptions on demands distributions, we show a non-cooperative equilibrium exists for each distribution network design. We also propose distinctive coordination mechanisms corresponding to the pricing policies. Using these mechanisms in each design of the distribution network, profits of the manufacturer and retailers are better off compared to the non-cooperative situation. Lastly, numerical examples presented in the paper, comprising the sensitivity analysis of some key parameters, seek to compare the results of different distribution network designs under various pricing policies and yield some applicable managerial insights.
Distribution network design, Game theory
Multi-location newsvendors
supply chain coordination
Buy back contract
2014
06
01
988
1006
http://scientiairanica.sharif.edu/article_3536_6586a0b26cce8a8a076f697baece5108.pdf
Scientia Iranica
Scientia Iranica
1026-3098
1026-3098
2014
21
3
An enhanced invasive weed optimization for makespan minimization in a flexible flowshop scheduling problem
Fariborz
Jolai
Reza
Tavakkoli-Moghaddam
M.
Rabiee
E.
Gheisariha
In previous investigations in the field of flexible flow shop scheduling problem, rework probability for operations was ignored. As these kinds of problems are NP-hard, so we presented an enhanced invasive weed optimization (EIWO) meta-heuristic algorithm in order to solve the addressed problem with probable rework times, transportation times with a conveyor between two subsequent stages, different ready times and anticipatory sequence dependent setup times. The optimization criterion is to minimize makespan. Although invasive weed optimization (IWO) is an efficient algorithm and has been attracted by many researchers recently, but to increase the capability of IWO, we added mutation operation to enhance the exploration in order to prevent sticking in local optimum. In addition, affinity function is embedded to obstruct premature convergence. With these changes, we balance exploration and exploitation of IWO. Since, the performance of our proposed algorithm depends on parameters values, hence, we applied a popular design of experimental methodology called response surface method (RSM). To evaluate the proposed algorithm, first some random test problems were generated and compared with three benchmark algorithms. The related results were analyzed by statistical tools. The experimental results and statistical analyses demonstrated that the proposed EIWO was effective for the problem.
IWO
Flexible flow shop
response surface methodology
rework
transportation time
anticipatory sequence dependent setup time
2014
06
01
1007
1020
http://scientiairanica.sharif.edu/article_3537_18a03116922c9dadf054343543453c5c.pdf
Scientia Iranica
Scientia Iranica
1026-3098
1026-3098
2014
21
3
A Particle Swarm Optimization-based Algorithm for Flexible Assembly Job Shop Scheduling Problem with Sequence Dependent Setup Times
Saeid
Nourali
Narges
Imanipour
Abstract This paper considers a flexible assembly job shop scheduling problem with the sequence dependent setup times, and its objective is minimization of makespan which integrates the process planning and scheduling activities. This is a combinatorial optimization problem with substantially large solution space, suggesting that it is highly difficult to find the best solution with the exact search method. In this paper a particle swarm optimization based algorithm is proposed which applies a novel solution representation method to fit the continuous nature of algorithm in the discrete modeled problem. The numerical experiments also have been performed to demonstrate the effectiveness of the proposed algorithm.
Flexible job shop scheduling
assembly
sequence dependent setup time
Particle swarm optimization
2014
06
01
1021
1033
http://scientiairanica.sharif.edu/article_3538_b6fb4fd47dda2535f8bd63f077e6bbbd.pdf
Scientia Iranica
Scientia Iranica
1026-3098
1026-3098
2014
21
3
Risk analysis of sourcing problem using stochastic programming
M.
Keyvanloo
A.M.
Kimiagari
A.
Esfahanipour
Nowadays Sourcing problemhas become more challenging for supply chain members. Different types of sourcing for different market conditions are presented in the literature. In this paper an option contract as an efficient tool for sourcing is developed in a multi-period setting in which the price and demand follow two stochastic processes. Sourcing decision is analyzed from risk neutral and risk averse decision maker’s point of view. This paper applies the stochastic programming approach to model the presented option contract based on price and demand uncertainties. Next, using CVaR as a coherent risk measure, the effects of risk on sourcing problem are studied. By numerical example, using the presented efficient frontier, the simulation results of our developed models show that the decision maker can make a trade-off between risk and cost associated with the sourcing problem. The paper also performs sensitivity analysis in order to demonstrate the effects of change in cost parameter on results of our option model.
Supply Contract
Risk measure
Efficient frontier
Option contract
Uncertain demand
Uncertain price
stochastic process
Stochastic programming
2014
06
01
1034
1043
http://scientiairanica.sharif.edu/article_3539_033413b4bb216f8e2844875eb835db1d.pdf
Scientia Iranica
Scientia Iranica
1026-3098
1026-3098
2014
21
3
Using group method of data handling to model customer choice behaviour
B.
Zhu
C.H.
He
Y.
Niu
Choice modelling is valuable for understanding and predicting customer behaviour. This study introduces the Group Method of Data Handling (GMDH) into choice modelling and applies this new technique to model consumer choice in the longdistance communication market. When we compare the GMDH with the Articial Neural Network (ANN) and logit models, the results show that the new model provides better predictions of customer choice than the ANN and logit models. In addition, the new model can identify the important explanatory variables that aect customer choice, and reveal how the variables aect this choice, which cannot be directly accomplished using the ANN model. This advantage will help rms to better analyse the behaviour of their customers and, thereby, develop suitable marketing strategies.
Choice modelling
Group Method of Data Handling (GMDH)
Articial Neural Network (ANN)
Long- Distance communication mode
2014
06
01
1051
1060
http://scientiairanica.sharif.edu/article_3540_dd390483ffd80b22a8acf90b73ec3c7f.pdf
Scientia Iranica
Scientia Iranica
1026-3098
1026-3098
2014
21
3
On Competence of Vendor Managed Inventory in Supply Chains Using Basic Mathematical Inventory Models
Milad
Jasemi
Alireza
Haji
Moslem
Gharibi
In this study a two-echelon single-vendor supply chain is selected to do a cost-based comparison between short-term performances of vendor managed inventory (VMI) and retailer managed inventory (RMI) while the inventory cost includes ordering and storing expenses; rate of consumption and price of good are constant; rate of production and pace of transportation are infinite and shortage is not allowed. The paper after a comprehensive literature review is followed by three cases of single retailer, -retailer and two-retailer chains. Unlike the second case, in the first case, VMI shows an absolute superiority to RMI and this is the reason of devising the third case in which a deeper analysis, including a typical performance assessment system for two-retailer chains, is done. The third case reveals that although VMI is not always the better choice but in most of conditions it can be chosen as the better approach
Inventory control
vendor managed inventory
Retailer Managed Inventory
Supply chain management
2014
06
01
1061
1071
http://scientiairanica.sharif.edu/article_3541_df15a0dd7e6255318b0b37954863fa3f.pdf
Scientia Iranica
Scientia Iranica
1026-3098
1026-3098
2014
21
3
A four-phase algorithm to improve reliability in series-parallel systems with redundancy allocation
A.
Ghafarian Salehi Nezhad
A.
Eshraghniaye Jahromi
M.H.
Salmani
F.
Ghasemi
In general, reliability is the ability of a system to perform and maintain its functions in routine, as well as hostile or unexpected, circumstances. The Redundancy Allocation Problem (RAP) is a combinatorial problem which maximizes system reliability by discrete simultaneous selection from available components. The main purpose of this study is to develop an eective approach to solve RAP, expeditiously. In this study, the basic assumption is considering Erlang distribution density for component failure rates. Another assumption is that each subsystem can have one of coldstandby or active redundancy strategies. The RAP is a NP-Hard problem which cannot be solved in reasonable time using exact optimization techniques. Therefore, an approach that combines an Ant Colony Optimization (ACO) algorithm as a meta-heuristic phase, and three other heuristics, is used to develop a solving methodology for RAP. Finally, to prove the eciency of the proposed approach, some well-known benchmarks in the literature are solved and discussed in detail.
Reliability optimization
Redundancy allocation
series-parallel system
Ant colony optimization
Heuristic algorithms
Parameter design
Taguchi approach
2014
06
01
1072
1082
http://scientiairanica.sharif.edu/article_3542_268599509946c3f91f984add433837ac.pdf
Scientia Iranica
Scientia Iranica
1026-3098
1026-3098
2014
21
3
A two-phase method for a multi-skilled project scheduling problem with discounted cash flows
B.H.
Tabrizi
R.
Tavakkoli-Moghaddam
S.F.
Ghaderi
This paper considers a multi-skilled project scheduling problem that is a newly developed extension of the resource-constrained project scheduling problem (RCPSP). The main difference in such problems compared with the classic scheduling problems is associated with the given resources, which are just depended on the human type. Additionally, the net present value of a given project is considered by the cash in and outflows to guarantee the project success. To solve the given problem, an enhanced two-phase method is proposed using the genetic and path relinking algorithms, whose parameters are tuned by the Taguchi method to provide robust comparisons. Furthermore, the potential changes in the project execution method are considered for some of the mostly used payment methods. Finally, some different-sized instances are tested to check the performance and efficiency of the proposed method.
Multi-skilled project scheduling problem
Cash flows
Genetic algorithm
Path relinking algorithm
2014
06
01
1083
1095
http://scientiairanica.sharif.edu/article_3543_80067895a118d9217575f0df6074e93e.pdf
Scientia Iranica
Scientia Iranica
1026-3098
1026-3098
2014
21
3
Economic-statistical design of adaptive X-bar control chart: a Taguchi loss function approach
F.
Amiri
K.
Noghondarian
Rassoul
Noorossana
Along with the widespread use of Taguchi methods in product design, denition of the loss function has been integrated with numerous models which require quality cost estimation. In this paper, the economic-statistical design of a variable sampling X-bar control chart is extended using the Taguchi loss function to improve chart effectiveness from a quality cost point of view. The effectiveness of the proposed schemes is evaluated by comparing optimal expected costs and statistical performance with each other and with the xed sampling policy. Results indicate a satisfactory performance for the proposed models.
Adaptive control chart
Variable sample size
Variable sampling interval
Taguchi loss function
Economic-statistical design
2014
06
01
1096
1104
http://scientiairanica.sharif.edu/article_3544_a1cd34df66f634956fa1694da05f94e8.pdf
Scientia Iranica
Scientia Iranica
1026-3098
1026-3098
2014
21
3
Developing functional process capability indices for simple linear prole
R.
Nemati Keshteli
R.
Baradaran Kazemzadeh
A.
Amiri
R.
Noorossana
A prole is a relation between one response variable and one or more explanatory variables that represent the quality of a product or the performance of a process. Process Capability Indices (PCI) are measured to evaluate processes in producing conforming products. All existing methods that measure process capability indices in a simple linear prole consider response variables at some levels of explanatory variable and ignore all ranges of x-values. In this paper, a functional approach is proposed to measure the process capability index of simple linear proles in all ranges of explanatory variable. This new approach follows the traditional denition of process capability indices and leads to their accurate values for a simple linear prole. The functional approach uses a reference prole, functional specication limits and functional natural tolerance limits to present a functional form of process capability indices. This functional form results in measuring the process capability at each level of the explanatory variable in a simple linear prole, as well as the unique value of a process capability index for a simple linear prole. A comparison study using a non-conforming proportion method shows the better performance of functional process capability indices in measuring the process capability in a simple linear prole.
Prole monitoring
Simple linear prole
Functional process capability index
Specication limits
Natural tolerance limits
2014
06
01
1096
1104
http://scientiairanica.sharif.edu/article_3545_76d6f1081abd9cdbdfc49773a87dca99.pdf
Scientia Iranica
Scientia Iranica
1026-3098
1026-3098
2014
21
3
Research on the Stochastic Hybrid Multi-attribute Decision Making Method Based on Prospect Theory
Hongliang
Yu
Peide
Liu
Fang
Jin
With respect to the stochastic hybrid multi-attribute decision making problems with interval probability and unknown attribute weight, a multi-attribute decision making method based on prospect theory is proposed. To begin with, the hybrid attribute vales, including real numbers, interval numbers, triangular fuzzy numbers, linguistic variables, uncertain linguistic variables and intuitionistic fuzzy values, are converted to trapezoidal fuzzy numbers, and intervalprobability is expressed by trapezoidal fuzzyprobability; the prospectvalue function of the trapezoidal fuzzy numbers for every alternative under every attribute and everynatural state based on the decision-making reference point of each attribute, and the weight function of trapezoidal fuzzyprobability,can be constructed; then the prospect value of attribute for every alternative is calculated through prospectvalue function and the weight function. Then, a maximizing deviation method is used to determine the attribute weightsand the weighted prospect value of alternative is get by weighting the prospect values, and all the alternatives are ranked according to the expected values of the weighted prospect values. Finally, an illustrate example is given to show the decision-making steps, the influence on decision making for different parameter values in value function and weight function and different decision-making reference points. ing
Prospect Theory
intervalprobability
uncertain linguistic variables
hybrid Decision making
stochastic decision-making
multi-attribute decision-mak
2014
06
01
1105
1119
http://scientiairanica.sharif.edu/article_3546_d035b69fe563b59c6da9f9fadcf086fb.pdf
Scientia Iranica
Scientia Iranica
1026-3098
1026-3098
2014
21
3
A master production schedule warning approach for cement equipment manufacturing enterprises
L.B.
Sun
S.S.
Guo
S.Q.
Tao
Y.B.
Li
B.G.
Du
Reducing product delivery time is a key factor for enterprises in increasing their core competitiveness. In order to resolve problems, including lack of a warning and monitoring system for Master Production Schedules (MPS) in cement equipment manufacturing enterprises, we propose a warning echanism based on theoretical nish percentage and actual nish percentage. First, an MPS model, based on the product Manufacturing Bill Of the Material (MBOM), is proposed. Second, we present an approach for generating planned time, actual time, actual nish percentage and theoretical nish percentage, and yellow and red warnings are introduced to evaluate whether the production plan is normal or not. Finally, we use an example to illustrate the proposed algorithm process. Experimental results have shown that the proposed approach is able to support MPS warning.
MPS
MBOM
Yellow warning
Red warning
2014
06
01
1120
1127
http://scientiairanica.sharif.edu/article_3547_148b4fc1561c1eb4b697a4b9192e7fbd.pdf