متد و روش تصمیم گیری چند معیاره (MCDM) فازی یکپارچه و برنامه نویسی چند هدفه جهت انتخاب تامین کنندگان و تخصیص سفارش در زنجیره تامین سبز (GSC)

ABSTRACT Integrated fuzzy multi criteria decision making method and multiobjective programming approach for supplier selection and order allocation in a green supply chain

In a competitive environment, the selection of suppliers represents one of the most critical issues facing manufacturing firms. The cost of raw materials in such industries comprises the major portion of a product’s final cost, and the selection of appropriate suppliers significantly reduces purchasing costs (Ghodsypour and O’Brien, 1998, 2001; Demirtas and Ustun, 2008; Amid et al., 2011). Due to governmental legislation and an increased awareness among people of protecting the environment, firms cannot ignore environmental issues if they want to maintain their competitive advantage in this globalization trend. Growing environmental concerns means it is necessary to consider environmental pollution issues that accompany industrial development in supply chain management activities, leading to the emerging concept of green supply chain management (GSCM) (Hsu and Hu, 2009; Diabat and Kannan, 2011). In recent years, companies have implemented several regulatory checks and programs to ensure that suppliers can provide materials and services both with high quality and also dedicated to environmental standards (Awasthi et al., 2010; Kuo et al., 2010). GSCM is generally recognized as monitoring suppliers based on their environmental performance and having collaboration only with green suppliers that satisfy environmental standards (Hsu and Hu, 2009). Essentially, two types of supplier selection are prominent. In the first type (single sourcing), one supplier can satisfy the entire buyer’s needs and the buyer needs to make only one decision: which supplier is the best. In the second and more common type (multiple sourcing), more than one supplier must be selected because no single supplier can satisfy all the buyer’s orders. Hence, companies need to select both the best suppliers and how much quantity should be allocated among them for creating a constant environment of competitiveness (Alyanak and Armaneri, 2009). Accordingly, multiple sourcing provides significant assurance of timely delivery and order flexibility due to the diversity of the firm’s total orders (Ghodsypour and O’Brien, 1998; Kumar et al., 2004; Aissaoui et al., 2007; Jolai et al., 2011). There are different individual and integrated approaches for supplier selection. Ho et al. (2010) reviewed various integrated approaches for multiple sourcing suppliers and concluded that the integrated AHPeGP approach is most popular. The extensive application of the analytic hierarchy process (AHP) method is due to its simplicity, ease of use, and flexibility (Kannan and Vinay, 2008; Borade et al., 2013). Goal programming (GP) is used widely for solving multi criteria decision making (MCDM) and multi-objective decision making (MODM) problems because of its simplicity and flexibility. Goal programming can handle relatively large numbers of decision variables, resource constraints, and objectives (Jolai et al., 2011; Dubey et al., 2012). Goal programming is a branch of multi-objective optimization; it extends linear programming to deal with multiple, normally conflicting objectives (Jolai et al., 2011; Chang, 2011; Lee et al., 2009b). Chai et al. (2012) provided a systematic literature review on 123 journal articles published from 2008 to 2012 on the application of decision making (DM) techniques for supplier selection and indicated that the most frequently used technique is AHP followed by linear programming (LP) and Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). Wu and Barnes (2011) reviews the literature on supply partner decision-making published between 2001 and 2011 and concluded that the most famous combined approaches for supplier selection problem are the models that include mathematical programming, AHP/ANP, or fuzzy set approach. Hence, this paper introduces a multi-objective programming approach to solve the multiple sourcing green suppliers’ problems. At first, the fuzzy analytic hierarchy process (FAHP) and TOPSIS methods are used to assign criteria weight and to rank all alternative suppliers. In the next phase, we construct a weighted max-min fuzzy multi-objective model to determine the order quantity of each green supplier based on various constraints