نشریه مدیریت صنعتی
سال چهارم شماره 9 (پاییز و زمستان 1391)

This article proposes composition of fuzzy sets theory with discrete-event simulation and puts it into application in order to model uncertain activity duration in simulating a real-world system. The purpose of this paper is to assess the usefulness of fuzzy simulation for modeling uncertain activity duration، especially when insufficient or no sample data is available. In this research، fuzzy numbers are used to describe uncertain activity durations which is reflecting vagueness، imprecision and subjectivity in the estimation of them. Initially، a simulation model is designed on the basis of classic (probability distribution-based) approach and then by using activity durations estimated by experts، this model is changed to a fuzzy one. Based on a number of common probability distributions، Some simulation models are designed and their results are compared with those of fuzzy simulation model. The results indicates that، firstly، fuzzy simulation outputs are achieved through only one cycle of fuzzy discrete-event simulation and secondly، the range of fuzzy simulation outputs entails the results of multiple cycles of probability distribution-based simulation experiments. Therefore، the fuzzy simulation is an acceptable approach to present the real system; especially in uncertain circumstances that no sample data is available or there is some insufficient or unreliable data.

The purpose of this paper is to improve supply chain relationships in Iranian small and medium-sized enterprises (SMEs) in automotive parts industry. For this reason، an Importance-Performance Analysis (IPA) has been employed to categorized supply chain relationships metrics. Also، the questionnaire method is used for gathering information. The paper identified thirteen supply chain relationships factors and related metrics for them، used by researchers and practitioners. The questionnaire answered by 175 Iranian small and medium-sized enterprises (SMEs) in automotive parts industry. Afterward، the IPA Matrix is developed and some recommendations presented for improving supply chain relationships in the Iranian SMEs.

Structural and environmental complexity and also Competitive challenges make priotrizing of technology development so critical for policy makers، managers and industries planner. Although the necessity of this subject has been mentioned in literature، but there is not any specific process for technology planning at industry level. because of This theoretical gap، researches uses the technology planning models of firm level or policy making models of national level for identifying and selecting the key technologies of an industry، that both of these approaches have some deficiencies. In this paper with the aid of qualitative approach and using grounded theory methodology we propose a model consist of three level for industry technology planning. The high priorities of technology development are determined in macro level of model. In meso level the portfolio of technology areas select to respond to the critical requirement of system. In micro level، we select the technology alternatives which have the potential of responding to performance targets. After analyzing the proposed model، we suggest some research themes for future working.

Window Analysis is a known technique to evaluate performance during the time periods based on data envelopment analysis. In application of Window Analysis is assumed that efficient frontier have not changed during the periods in the study. Unlike the Window Analysis، Malmquist index tries to identify difference between efficient frontiers and separated them. But the means of different frontier in the Window Analysis are the their general changes that can be studied with statistical methods. While from this standpoint of Malmquist، limited points of frontiers is considered that using mathematical methods is indivisible. In this study، Considering conformity of Production Possibility Set in Malmquist index with window analysis with width is equal to or greater، a framework is proposed that enables the user by determining appropriate length of the window that prevents violating basic assumption، and by using appropriate kind of Malmquist index، calculate the differences point in frontiers in evaluation of performance.

The concept of coordination in supply chain management is different from the viewpoint of the roles of this chain and this difference causes more uncoordination at the entire of the supply chain. Hence، regarding to the importance of this subject at the performance of supply chain، the clarification of the coordination concept as a casual model seems very necessary. In this research، the cognitive mapping and browser software have been used for the modeling of the mental concepts of the selected experts at Iran automotive industry. The coordination among the maps of different experts has been analyzed by the UCINET software and if it confirmed، the maps had been combined together to the access of the consensus map of the Iran automotive industry. Afterwards، it followed by setting the 60، 70 and 100% difference among the agreed maps of experts and their relations together; finally the tests of block analysis demonstrated the accuracy of above classification.

Although economic and managerial literature is replete with studies that probe about productivity but only a few studies decompose it to its components (technological changes، managerial efficiency changes and scale efficiency changes) and analysis their share in productivity changes (positively or negatively). Accordingly، this article attempts to explain the issue by decompose productivity to its factors in non-metallic minerals industry as one of the main industry in Iran in 2 and 4 digit industrial code. Using the data envelopment analysis and Malmquist index and Panel Data Model، the results of this paper indicate that impact of productivity components on its changes strongly depends on the level of the industry level. In term of policy، the findings show that for productivity growth in industry sector necessarily a same strategy is not acceptable and each industry base on their structure needs different changes for approving their productivity.

Agility is perceived as the dominant competitive vehicle for all organizations in an uncertain and ever-changing business environment. Many of the enterprises in present competitive environment need to have strategic plan for achieving agility. For this purpose، they should identify strategies in order to centralize on the agility capabilities and providers. Indeed، each enterprise for achieving agility need to have deferent amount of the capabilities and ensures that the agility providers can satisfy the agility capabilities. The aim of this paper is to create methodology to rank and select the agility providers that raise the agility of enterprises. For this purpose، in this paper a multi-criteria decision makingtechnique is used that composed of the ANP and DEMATEL. Analytic Network Process (ANP) is Relative newmethod in multi-criteria decision making area can systematically consider the interdependence between criteria and alternatives. The DEMATEL techniquecanalsodetermine the cause and effect relationships and the inner dependence among criteria usedto improve the ANP results.

By increasing complexity، level of uncertainty and risk in the chain goes up. Hence supply chain risk management has become a major issue in the organization. In this study، Supply Chain Risk from this perspective will be investigated. This study utilizes a grey relational analysis and Fuzzy VIKOR to establish a complete and accurate evaluation model for ranking factors affecting on supplier risk. Innovation of this research is combining fuzzy Delphi method، the grey relational analysis and fuzzy VIKOR to identify and ranking factors affecting on suppliers risk and was conducted for the first time in alloy steel industry. After the analysis «single sourcing» and «available capacity» were identified as important factors. For this purpose، factors affecting on the risks incurred by the supplier on Alloy Steel industry were identified using Fuzzy Delphi. Then these factors evaluated and ranked using Grey Relation Analysis and fuzzy VIKOR. After the most important risk factors that need to be improved، identified and more appropriate strategies is offered.