Journal title
http://www.ijsom.com
International Journal of Supply and Operations Management - Journal articles for year 2014, Volume 1, Number 3Yektaweb Collection - https://yektaweb.comen2014/11/10Mathematical Modelling for EOQ Inventory System with Advance Payment and Fuzzy Parameters
http://system.khu.ac.ir/ijsom/browse.php?a_id=2160&sid=1&slc_lang=en
This study considers an EOQ inventory model with advance payment policy in a fuzzy situation by employing two types of fuzzy numbers that are trapezoidal and triangular. Two fuzzy models are developed here. In the first model the cost parameters are fuzzified, but the demand rate is treated as crisp constant. In the second model, the demand rate is fuzzified but the cost parameters are treated as crisp constants. For each fuzzy model, we use signed distance method to defuzzify the fuzzy total cost and obtain an estimate of the total cost in the fuzzy sense. Numerical example is provided to ascertain the sensitiveness in the decision variables about fuzziness in the components. In practical situations, costs may be dependent on some foreign monetary unit. In such a case, due to a change in the exchange rates, the costs are often not known precisely. The first model can be used in this situation. In actual applications, demand is uncertain and must be predicted. Accordingly, the decision maker faces a fuzzy environment rather than a stochastic one in these cases. The second model can be used in this situation. Moreover, the proposed models can be expended for imperfect production process.M. PalanivelAn Efficient Genetic Algorithm to Solve the Intermodal Terminal Location problem
http://system.khu.ac.ir/ijsom/browse.php?a_id=2162&sid=1&slc_lang=en
The exponential growth of the flow of goods and passengers, fragility of certain products and the need for the optimization of transport costs impose on carriers to use more and more multimodal transport. In addition, the need for intermodal transport policy has been strongly driven by environmental concerns and to benefit from the combination of different modes of transport to cope with the increased economic competition. This research is mainly concerned with the Intermodal Terminal Location Problem introduced recently in scientific literature which consists to determine a set of potential sites to open and how to route requests to a set of customers through the network while minimizing the total cost of transportation. We begin by presenting a description of the problem. Then, we present a mathematical formulation of the problem and discuss the sense of its constraints. The objective function to minimize is the sum of road costs and railroad combined transportation costs. As the Intermodal Terminal Location Problemproblem is NP-hard, we propose an efficient real coded genetic algorithm for solving the problem. Our solutions are compared to CPLEX and also to the heuristics reported in the literature. Numerical results show that our approach outperforms the other approaches.Mustapha OudaniVendor Managed Inventory of a Single-vendor Multiple-retailer Single-warehouse Supply Chain under Stochastic Demands
http://system.khu.ac.ir/ijsom/browse.php?a_id=2158&sid=1&slc_lang=en
In this study, a vendor-managed inventory model is developed for a single-vendor multiple-retailer single-warehouse (SV-MR-SV) supply chain problem based on the economic order quantity in which demands are stochastic and follow a uniform probability distribution. In order to reduce holding costs and to help balanced on-hand inventory cost between the vendor and the retailers, it is assumed that all inventory is held at a central warehouse with the lowest cost among the parties. The capacity of the central warehouse is limited. The objective is to find the warehouse replenishment frequency, the vendor's replenishment frequency, the order points, and the order quantities of the retailers such that the total inventory cost of the integrated supply chain is minimized. The proposed model is a mixed integer nonlinear programming problem (MINLP); hence, a genetic algorithm (GA) is utilized to solve this NP-hard problem. The parameters of the GA are calibrated using the Taguchi method to find better solutions. Some numerical illustrations are solved at the end to demonstrate the applicability of the proposed methodology and to evaluate the performance of the solution method.Seyed Taghi Akhavan NiakiImproving Employee Satisfaction Priority through Performance Control Matrix
http://system.khu.ac.ir/ijsom/browse.php?a_id=2175&sid=1&slc_lang=en
The study addresses Performance Control Matrix (PCM) to determine service quality items of priority for improvement. Most businesses focus on customer satisfaction when undertaking surveys of satisfaction and dissatisfaction, while generally neglecting employee satisfaction. Therefore, this study develops an integrated model to improve service quality in Taiwanese finance industry employees. A questionnaire is designed to determine the priority of improvement objectives derived from certain questionnaire items that fall into the improvement zone of the PCM. Ten items are found to fall into the improvement zone of the PCM. The present results show that the finance industry employees surveyed in Taiwan were dissatisfied with their job security, salaries, annual bonus, and fair distribution of operational profits. The ten improvement items mostly belong to two dimensions - ‘Pay and Benefits’ and ‘Motivation’. The managers of the financial institutions should seek to improve these quality attributes by devoting more resources to these items, thus promoting employee satisfaction.Shun-Hsing ChenA New Approach for Sequencing Loading and Unloading Operations in the Seaside Area of a Container Terminal
http://system.khu.ac.ir/ijsom/browse.php?a_id=2159&sid=1&slc_lang=en
Due to the considerable growth in the worldwide container transportation, optimization of container terminal operations is becoming highly needed to rationalize the use of logistics resources. For this reason, we focus our study on the Quay Crane Scheduling Problem (QCSP), which is a core task of managing maritime container terminals. From this planning problem arise two decisions to be made: The first one concerns tasks assignment to quay crane and the second one consists of finding the handling sequence of tasks such that the turnaround time of cargo vessels is minimized. In this paper, we provide a mixed-integer programming (MIP) model that takes into account non-crossing constraints, safety margin constraints and precedence constraints. The QCSP has been shown NP-complete, thus, we used the Ant Colony Optimization (ACO), a probabilistic technique inspired from ants’ behaviour, to find a feasible solution of such problem. The results obtained from the computational experiments indicate that the proposed method is able to produce good results while reducing the computational time.Azza LajjamSystem Dynamics Modeling in Entrepreneurship Research: A Review of the Literature
http://system.khu.ac.ir/ijsom/browse.php?a_id=2161&sid=1&slc_lang=en
System dynamics is a strategic approach for modeling complex systems and analyzing their behavior. Dynamic behavior in entrepreneurial system can be modeled using System Dynamics Approach and dynamic hypotheses about the system`s behavior can be proposed and tested using simulation and computer aided tools. However, as the review of literature shows, studies which link system dynamics modeling with entrepreneurship are rare and fragmented. This article presents a review of studies on the subject followed by integration and discussion on main research issues that have been the focus of previous studies. The main aim of this review is to categorize the available research related to the application of system dynamics modeling in entrepreneurship to integrate research and enable recommendations for future research. The Results reveal that the previous research could be categorized under a two dimensional taxonomy composed of level of analysis and level of modeling. The Level of analysis has three categories: micro level, meso level and macro level. The Level of modeling has six hierarchical levels. This study identifies several gaps in the literature and discusses the future directions in this field.Amir Mohammad ColabiAnalyzing the Operations Strategies of Manufacturing Firms Using a Hybrid Grey DEA approach – A case of Fars Cement Companies in Iran
http://system.khu.ac.ir/ijsom/browse.php?a_id=2174&sid=1&slc_lang=en
In competitive markets, the operations strategies of companies are normally formulated based on their competitive advantages. An effective operations strategy should maintain and improve competitive advantages based on the capabilities of the corporate operations resources. Considering the market requirements and the operational performance of the rivals is the key for success and survival of a company in the competition. Therefore, recognizing where a company stands in comparison with its rivals and adopting the appropriate operations strategy plays vital roles in the success of companies. This paper proposes a method for comparing and ranking operations strategies of companies based on the concept of efficient frontier using data envelopment analysis (DEA) in grey environment. In the aforementioned method, DEA is used to evaluate the efficiency of operations strategies of manufacturing firms. Also, grey theory is used to support the uncertainty of the experts’ opinions regarding the inputs and outputs of the DEA model. Then the respective units are ranked, and analyses are performed. The proposed approach is applied for the entire nine cement factories of Fars Province in Iran, and the units are ranked, respective analyses are presented regarding the efficient and inefficient units.Mehdi Abbasi