رویکرد MCDM ترکیبی جدید بر اساس DEMATEL فازی، ANP فازی و TOPSIS فازی برای ارزیابی تامین کنندگان سبز

It is well known that “green” principles and strategies have become vital for companies as the public awareness increased against their environmental impacts. A company’s environmental performance is not only related to the company’s inner environmental efforts, but also it is affected by the suppliers’ environmental performance and image. For industries, environmentally responsible manufacturing, return flows, and related processes require green supply chain (GSC) and accompanying suppliers with environmental/green competencies. During recent years, how to determine suitable and green suppliers in the supply chain has become a key strategic consideration. Therefore this paper examines GSC management (GSCM) and GSCM capability dimensions to propose an evaluation framework for green suppliers. However, the nature of supplier selection is a complex multi-criteria problem including both quantitative and qualitative factors which may be in conflict and may also be uncertain. The identified components are integrated into a novel hybrid fuzzy multiple criteria decision making (MCDM) model combines the fuzzy Decision Making Trial and Evaluation Laboratory Model (DEMATEL), the Analytical Network Process (ANP), and Technique for Order Performance by Similarity to Ideal Solution (TOPSIS) in a fuzzy context. A case study is proposed for green supplier evaluation in a specific company, namely Ford Otosan.

Money, components, processes and information flows might establish a supply chain management system but simultaneously, due to government legislation and increasing awareness among the people to protect the environment; firms today cannot ignore environmental issues if they want to survive in the global market. In this sense, green supply chain management (GSCM) has emerged as a way for firms to achieve profit and market share objectives by lowering environmental impacts and increasing ecological efficiency (van Hock & Erasmus, 2000). In response to demands, companies have to find ways to incorporate environmental and social aspects into their supply chain management. In order to reap the greatest benefits from environmental management, firms must integrate all members in the green supply chain (GSC) (Lee, Kang, Hsu, & Hung, 2009). Among these expectations, increasing attention is devoted to suppliers’ social responsibility with a particular focus on fair and legal use of natural resources. Hence, strategic partnership with environmentally, socially and economically powerful suppliers should be integrated within the GSC for improving the performance in many directions including reducing costs and lead time, eliminating wastages, improving quality and flexibility to meet the needs of the customers, etc. For this reason, the aim of this study is to propose an evaluation model to judge the appropriateness of suppliers for an organization which has environmental goals and measure the validity of the model with a real case study. There are various mathematical techniques for evaluation of suppliers, such as data envelopment analysis (DEA) (Wu, 2009), heuristics (He et al., 2009 and Sen et al., 2007), analytic hierarchy process (AHP) (Sevkli, Koh, Zaim, Demirbag, & Tatoglu, 2007), fuzzy AHP (Chan and Kumar, 2007, Lee et al., 2009 and Rao and Holt, 2005), fuzzy goal programming (Kumar et al., 2006 and Tsai and Hung, 2009), fuzzy analytic network process (ANP) (Lin, 2009 and Tuzkaya and Önüt, 2008) in literature. For the purpose of evaluating and selecting green suppliers, both qualitative and quantitative factors must be considered. Thus, green supplier selection is a kind of multiple criteria decision making (MCDM) problem and we need to employ MCDM methods to handle it appropriately. Here emphasis is placed on the relationships of factors which can be handled by ANP (Saaty, 1996) effectively. The ANP can deal with the dependence in feedback systematically. In this study also Decision Making Trial and Evaluation Laboratory (DEMATEL) method (Gabus & Fontela, 1972) is used to extract the mutual relationships of interdependencies within criteria and the strength of interdependence. Lastly to choose the alternative for ideal solution of this problem, Technique for Order Performance by Similarity to Ideal Solution (TOPSIS) is used. However it should not be ignored that the fuzzy nature of human life makes these kinds of MCDM analysis more difficult. Yet for human being’s subjective judgment, a theory needed in measuring the ambiguity of these concepts. Therefore, fuzzy logic (Zadeh, 1965) is used in evaluations that allows for uncertainty among factors. Briefly, fuzzy DEMATEL (Chen et al., 2008, Tseng, 2009a and Wu and Lee, 2007); fuzzy ANP (Liu and Lai, 2009, Tuzkaya et al., 2009 and Yüksel and Dağdeviren, 2010); and fuzzy TOPSIS (Salehi and Tavakkoli-Moghaddam, 2008, Yong, 2006 and Iç and Yurdakul, 2010) approaches used by several authors are workable. Because by applying these theories, it can be easy to discover things inside the complex problem. In the literature there are some works on these methods, but there is not any research that combines these three methods together. Thereby, this study proposes a new integrated approach that could cope with the interdependencies among various criteria in fuzzy environment. Ford Otosan is selected as a case company in this study for the evaluation of green supplier alternatives. The supplied case study provides additional insights for research and practical applications. The organization of the paper is then as follows. The paper begins with the literature survey of GSCM. Then, after a brief review of methodologies, various main components of the GSCM are examined to structure a framework for green supplier evaluation. The next section includes the illustration of the proposed green supplier methodology through the case of Ford Otosan. The paper concludes with future directions.

This study suggests a novel hybrid MCDM approach to evaluate green suppliers for the need of improving GSCM initiatives. Based on the literature survey and with the validation of industrial experts, possible green supplier evaluation criteria were defined and a new evaluation model was formulated. The proposed model was implemented in Ford Otosan, one of the pioneering companies about environmental subjects in Turkey. The combined fuzzy ANP and fuzzy DEMATEL approaches used in this study offered a more precise and accurate analysis by integrating interdependent relationships within and among a set of criteria. Moreover, fuzzy TOPSIS method helped to choose the alternative for ideal solution of this problem efficiently. While it is believed that the presented model provides value, there are also further points that can be included. To our knowledge, no previous work investigated such a problem by an integrated method with DEMATEL, ANP, and TOPSIS in fuzzy environment. As the proposed approach is novel, it might be applied to other MCDM problems.