Journal of Operational Research and Its Applications ( Applied Mathematics ) - Lahijan Azad University

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Increasing in production level of production systems, which is the unintended consequence of industrial development, has grown increasingly in recent years. The negative effects of this event have forced production processes to take solutions for maintaining their position in field of environmental management. One of these solutions is paying attention to the green issues in their supply chain, which is largely influenced by the performance of their suppliers. Therefore, evaluation and selection of green suppliers is a strategic decision in order to corporates’ success in the competitive market and maintain its social position. Due to the variety of evaluation criteria, their quantitative or qualitative nature and the fuzzy nature of qualitatile criteria, this research proposed a hybrid fuzzy MCDM approach based on fuzzy Delphi, fuzzy analytical hierarchy process and fuzzy VIKOR techniques to evaluate and select the green suppliers of Saipa corporation. For this purpose, first reviewing the literature, supplier selection criteria in green supply chain were investigated. Then, examining the current status of Saipa, consulting with the experts and using the Fuzzy Delphi method, more important criteria were identified. In the next stage, the final criteria were delivered to the experts by means of a pairwise comparison questionnaire and the required data for their prioritization based on the fuzzy analytical hierarchy process technique were collected. Finaly, the 100 suppliers of Saipa corporation were evaluated based on the fuzzy VIKOR technique. The results indicate that the proposed approach is an effective framework for prioritizing green suppliers of Saipa corporation.
 

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Today, with the development of a competitive environment attention to supply chain management has become a key issue in the commercial organizations. It has influenced all organizational activities ranging from raw material purchasing, production, reducing cost and after-sales service, etc. On the other hand, by increasing the volume of pollutants and increased attention to environmental issues, manufacturers have to expand their supply chains into a closed-loop supply chain (CLSC). In this paper, we attempt to deal with the environmental issues presented in the design of CLSC networks. For the consideration of environmental issues in the proposed network, we plan an integer nonlinear programming and use the GAMS to solve it. This model optimizes the flow of sectors and products in the CLSC and the number of trucks used for the forward supply chain. Finally, applicability of the proposed model is tested via a real case study in refrigerator manufacturing plant, and the results are analyzed in depth. The application of the developed model can help to increase companys’ profit by reducing transportation costs while reducing environmental impacts and creating a green image of the supply chain.

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The importance of social performance of corporate and business units has increasingly been emphasized by researchers and practitioners in recent years. Since green supply chains Play important roles in decreasing the pollution of business and corporate environments, social performance has a significant role in creating this supply chain; Therefore, in designing green supply chain social performance should be considered carefully. This paper addresses designing a model of social performance for green supply chain under uncertain conditions. To this end, first a multi-objective fuzzy mathematical programming model is designed. In this model, the objective functions include minimizing the costs and environmental impacts and maximizing the green supply chain of the social performance. To solve this model, an interactive fuzzy solution method is used. Finally, a real industrial case study is provided to measure the validity and effectiveness of the model.

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In the current decade, determining the most appropriate supplier as a strategic factor in the supply chain has attracted lots of consideration. On the other hand, organizations do necessary measures to implement green supply chain management in order to improve environmental and economic performance. An important way to implement green supply chain management, could be revising the method of purchase. Existing Vendor managed inventory is a business initiative that providers can maintain the existing units of purchased product. In this study, a Multi-objective mathematical model has been developed to solve a VMI problem in two echelon supply chain with suppliers and a buyer. To establish a green supply chain, this model minimizes the cost of VMI system and maximizes the value of the goal. Also, the two objectives problem has been one-objective using Global criteria method and a numeric example has been provided to illustrate adequacy of this strategy. The algorithm implemented and shows good results in reasonable time complexity. It also helps decision makers and managers in the optimal, efficient and low-cost solution (number of products and number of retailers and recapitalization cycles, etc.) in VMI discussion.

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An important way to implement green supply chain management is to revise the purchase method. In the past decade, how to determine the most suitable suppliers in the supply chain as a strategic factor, has been of interest to many. In the selection of lean suppliers, the supplier features include low cost, high quality and in agile supplier selection, features are speed, flexibility and quality. This study has been conducted in two phases. In the first phase, suppliers are ranked by using the combination of AHP and VIKOR and green criteria. Then, in the second stage, in order to assign the order to selected suppliers in the first phase, the model framework was designed, which included four goals of minimizing supply chain cost, minimizing delivery time (agile), minimizing waste products (lean) and maximizing attention to environmental issues. In the following, the multi objective problem is converted to a single objective problem by using a comprehensive L-P metric approach. Several numerical examples have been devised to describe the adequacy of this strategy. The implemented algorithm shows good results in convenient computational time.

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The present research aimed to identify the affective factors of the green supply chain in the Guilan steel industry with regards to a quantitative approach. The type of this study was applicable, and in terms of purpose, it is descriptive research. The present study used a mixed-method for data gathering by utilizing questionnaires and interview tools. The statistical population of the study consisted of steel industry experts and university professors in Guilan province. In the first stage, 25 individuals were selected through judgment, to identify the components and indicators of the green chain. In the second phase, 8 experts from the fuzzy DEMETEL questionnaire were provided. In the process of research, after identifying the indices using theoretical baseline study, 5 main factors and 25 sub-factors were identified using the fuzzy Delphi technique. Then, using the fuzzy DEMATEL technique, the degree of influence and effectiveness of each of the factors was found to be the most influential among the "environmental factor" with 0.792 and the "financial factor" with -0.996.

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One of the strategic decisions in the supply chain is an efficient network design which has a great impact on reducing costs and increasing customer satisfaction and lead to successful management of the network. Efficient design of green networks also reduces the pollution caused by carbon dioxide emissions. On the other hand, high speed of changes in the business environment has increased uncertainty and ambiguity of the chain. In order to reduce the risk and uncertainty of parameters, it is necessary to use of robust mathematical optimization models. In this research, a multi-objective, multi-product and multi-period model under uncertainty is presented. The first objective function is minimization of transportation costs and the second objective function is to minimize carbon emissions. In this model, both the amount of carbon emissions per time of transport between the plants and the distribution centers and the amount of carbon emissions of the plants and distribution centers are considered. In the constraints, a threshold limit for carbon emissions is considered so that if carbon emissions exceeds the threshold, the implementation of the project is not possible. Then a robust optimization approach is used to model the existing uncertainties. Finally, the results of the robust model are compared with the certain model.

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Selecting the right alternatives to efficient use of available resources has always been considered by managers. Supplier selection is especially important because it has a direct impact on the performance and profitability of an organization. Green supply chain management as an environmental innovation with the integration of environmental thinking and supply chain management is a necessity for today’s humans. The purpose of this study is to determine the criteria of green supplier selection in an automotive group and supplier selection based on the extracted criteria. Decision making criteria were identified through literature review, interaction with experts and using the Delphi method. These criteria include green design, green purchasing, green production, green transportation, environmental accountability, environmental management system, and pollution control. Then a new group voting analytical hierarchy process was designed and used to select a green supplier in Saipa. The research experts were consisted of thirty persons of supervisors, production managers and senior managers in Saipa Company. The results of the implementation of the new group voting analytical hierarchy process showed that by obtaining less information from experts and in a shorter time than other decision-making methods, acceptable results can be achieved.