Analysis of an M/G/1 Queue with Multiple Vacations, N-policy, Unreliable Service Station and Repair Facility Failures Wenqing Wu School of Mathematics & Software Science, Sichuan Normal University, Chengdu, Sichuan, 610068, China author Yinghui Tang School of Mathematics & Software Science, Sichuan Normal University, Chengdu, Sichuan, 610068, China author Miaomiao Yu School of Science, Sichuan University of Science and Engineering, Zigong, Sichuan, 643000, China author text article 2014 eng This paper studies an M/G/1 repairable queueing system with multiple vacations and N-policy, in which the service station is subject to occasional random breakdowns. When the service station breaks down, it is repaired by a repair facility. Moreover, the repair facility may fail during the repair period of the service station. The failed repair facility resumes repair after completion of its replacement. Under these assumptions, applying a simple method, the probability that the service station is broken, the rate of occurrence of breakdowns of the service station, the probability that the repair facility is being replaced and the rate of occurrence of failures of the repair facility along with other performance measures are obtained. Following the construction of the long-run expected cost function per unit time, the direct search method is implemented for determining the optimum threshold N* that minimises the cost function. International Journal of Supply and Operations Management Kharazmi University 23831359 1 v. 1 no. 2014 1 19 http://www.ijsom.com/article_1900_4881c207b3f40995f3c0c24db851ca30.pdf dx.doi.org/10.22034/2014.1.01 EOQ Model for Deteriorating Items with Exponential Time Dependent Demand Rate under Inflation When Supplier Credit Linked to Order Quantity Rakesh Prakash Tripathi Department of Mathematics, Graphic Era University, Dehradun (UK) India author Dinesh Singh Department of Mathematics, S.G.R.R. PG College, Dehradun (UK) India author Tushita Mishra Department of Mathematics, S.G.R.R. PG College, Dehradun (UK) India author text article 2014 eng In paper (2004) Chang studied an inventory model under a situation in which the supplier provides the purchaser with a permissible delay of payments if the purchaser orders a large quantity. Tripathi (2011) also studied an inventory model with time dependent demand rate under which the supplier provides the purchaser with a permissible delay in payments. This paper is motivated by Chang (2004) and Tripathi (2011) paper extending their model for exponential time dependent demand rate. This study develops an inventory model under which the vendor provides the purchaser with a credit period; if the purchaser orders large quantity. In this chapter, demand rate is taken as exponential time dependent. Shortages are not allowed and effect of the inflation rate has been discussed. We establish an inventory model for deteriorating items if the order quantity is greater than or equal to a predetermined quantity. We then obtain optimal solution for finding optimal order quantity, optimal cycle time and optimal total relevant cost. Numerical examples are given for all different cases. Sensitivity of the variation of different parameters on the optimal solution is also discussed. Mathematica 7 software is used for finding numerical examples. International Journal of Supply and Operations Management Kharazmi University 23831359 1 v. 1 no. 2014 20 37 http://www.ijsom.com/article_1901_1a5d3d8e8f818b5f034fcb884c8d82b8.pdf dx.doi.org/10.22034/2014.1.02 Location-Routing Problem with Fuzzy Time Windows and Traffic Time Shima Teimoori Department of Industrial Engineering, Elmo Honar University author Hasan Khademi Zare Department of Industrial Engineering, Yazd University author Mohammad Saber Fallah Nezhad Department of Industrial Engineering, Yazd University author text article 2014 eng The location-routing problem is a relatively new branch of logistics system. Its objective is to determine a suitable location for constructing distribution warehouses and proper transportation routing from warehouse to the customer. In this study, the location-routing problem is investigated with considering fuzzy servicing time window for each customer. Another important issue in this regard is the existence of congested times during the service time and distributing goods to the customer. This caused a delay in providing service for customer and imposed additional costs to distribution system. Thus we have provided a mathematical model for designing optimal distributing system. Since the vehicle location-routing problem is Np-hard, thus a solution method using genetic meta-heuristic algorithm was developed and the optimal sequence of servicing for the vehicle and optimal location for the warehouses were determined through an example.  International Journal of Supply and Operations Management Kharazmi University 23831359 1 v. 1 no. 2014 38 53 http://www.ijsom.com/article_1902_14027a3b0ff536b5ab658cbf0d9a2f0d.pdf dx.doi.org/10.22034/2014.1.03 No-idle time Scheduling of Open shops: Modeling and Meta-heuristic Solution Methods Bahman Naderi Department of Industrial Engineering, Faculty of Engineering, University of Kharazmi, Tehran, Iran author Vahid Roshanaei Department of Industrial Engineering, University of Toronto, Toronto, Canada author text article 2014 eng In some industries as foundries, it is not technically feasible to interrupt a processor between jobs. This restriction gives rise to a scheduling problem called no-idle scheduling. This paper deals with scheduling of no-idle open shops to minimize maximum completion time of jobs, called makespan. The problem is first mathematically formulated by three different mixed integer linear programming models. Since open shop scheduling problems are NP-hard, only small instances can be solved to optimality using these models. Thus, to solve large instances, two meta-heuristics based on simulated annealing and genetic algorithms are developed. A complete numerical experiment is conducted and the developed models and algorithms are compared. The results show that genetic algorithm outperforms simulated annealing. International Journal of Supply and Operations Management Kharazmi University 23831359 1 v. 1 no. 2014 54 68 http://www.ijsom.com/article_1903_0d44b3dce86860e16d114195990edcfb.pdf dx.doi.org/10.22034/2014.1.04 Alternative Axiomatic Characterizations of the Grey Shapley Value Sirma Zeynep Alparslan Gok Süleyman Demirel University, Faculty of Arts and Sciences, Department of Mathematics, 32260 Isparta, Turkey author Osman Palanci Süleyman Demirel University, Faculty of Arts and Sciences, Department of Mathematics, 32260 Isparta, Turkey author Mehmet Onur Olgun Süleyman Demirel University, Faculty of Arts and Sciences, Department of Mathematics, 32260 Isparta, Turkey author text article 2014 eng The Shapley value, one of the most common solution concepts of cooperative game theory is defined and axiomatically characterized in different game-theoretic models. Certainly, the Shapley value can be used in interesting sharing cost/reward problems in the Operations Research area such as connection, routing, scheduling, production and inventory situations. In this paper, we focus on the Shapley value for cooperative games, where the set of players is finite and the coalition values are interval grey numbers. The central question in this paper is how to characterize the grey Shapley value. In this context, we present two alternative axiomatic characterizations. First, we characterize the grey Shapley value using the properties of efficiency, symmetry and strong monotonicity. Second, we characterize the grey Shapley value by using the grey dividends. International Journal of Supply and Operations Management Kharazmi University 23831359 1 v. 1 no. 2014 69 80 http://www.ijsom.com/article_1904_c4411fe5a33e6024c0a9d9590b73a00e.pdf dx.doi.org/10.22034/2014.1.05 Analyzing Bullwhip Effect in Supply Networks under Exogenous Uncertainty Mitra Darvish Industrial Engineering Department, Alzahra University, Tehran, Iran. author Mehdi Seifabrghy Industrial Engineering Department, Alzahra University, Tehran, Iran author Mohammad Ali Saniei Monfared Industrial Engineering Department, Alzahra University, Tehran, Iran author Fatemeh Akbari Industrial Engineering Department, Alzahra University, Tehran, Iran author text article 2014 eng This paper explains a model for analyzing and measuring the propagation of order amplifications (i.e. bullwhip effect) for a single-product supply network topology considering exogenous uncertainty and linear and time-invariant inventory management policies for network entities. The stream of orders placed by each entity of the network is characterized assuming customer demand is ergodic. In fact, we propose an exact formula in order to measure the bullwhip effect in the addressed supply network topology considering the system in Markovian chain framework and presenting a matrix of network member relationships and relevant order sequences. The formula turns out using a mathematical method called frequency domain analysis. The major contribution of this paper is analyzing the bullwhip effect considering exogenous uncertainty in supply networks and using the Fourier transform in order to simplify the relevant calculations. We present a number of numerical examples to assess the analytical results accuracy in quantifying the bullwhip effect. International Journal of Supply and Operations Management Kharazmi University 23831359 1 v. 1 no. 2014 81 107 http://www.ijsom.com/article_1905_210f65d79e1a376b50f242f5dc2bab75.pdf dx.doi.org/10.22034/2014.1.06 Managing Virtual Product Development team: A Review Amir Mohammad Colabi Faculty of Entrepreneurship, University of Tehran, Tehran, Iran author Behrouz Zarei Faculty of Entrepreneurship, University of Tehran, Tehran, Iran author text article 2014 eng Although there are many potential benefits associated with the use of virtual product development teams, exploiting these benefits requires an appropriate management. Managing virtual product development team is a critical issue as many of these teams fail to accomplish their goals. Review of previous literature shows that body of knowledge in managing virtual product development teams is fragmented and inconsistent. The main objective of this paper is to categorize the previous research on the subject of virtual product development team management in order to integrate the research into a thematic model and to enable recommendations for future research. So, this study reviews and summarizes empirical research in the field, also conceptual and qualitative papers, experiences, reports and explorative case studies. Results show that there are three fields of research in this area, including: Virtual production and Virtual team in Product Development, Managing virtual team in R&D[1] and product development, Managing global virtual product development teams. In order to organize previous studies in this area, a thematic map is proposed which shows the structure and sequence of research. Finally, a comprehensive discussion on the future directions in this field is proposed. [1] Research & Development International Journal of Supply and Operations Management Kharazmi University 23831359 1 v. 1 no. 2014 108 128 http://www.ijsom.com/article_1906_ff3bbb743dc4e0546abf744ffbebc3fb.pdf dx.doi.org/10.22034/2014.1.07