عنوان مقاله [English]
Appropriate supplier selection method and order assignment play a major role in supply chain management. Supplier selection and order allocation problem have been studied in many papers up to now in single period without considering inflation. Decision making in multi period time horizon has many benefits such as economic savings comes from large size purchasing discounts. Increasing attention toward supplier partnership not only raises the importance of order allocation but also increases the significance of considering qualitative factors in this selection process. We proposed here a multi period problem considering inflation rate during purchasing periods that makes the problem much closer to the real situations. Supplier evaluation criteria in fuzzy multi criteria model are: cost, quality, service level and lead time which seem to be the most significant supplier evaluation criteria at the present time by considering intensive competition between different organizations.Here we use Analytical Hierarchy Process (AHP) with rough sets theory, the qualitative judgment can be quantified to make comparison more intuitive and reduce or eliminate assessment bias in pairwise comparison to help top manager in right decision making and giving weights to mentioned factors. Considering inflation in investment and purchasing during next periods , decrease attraction in decision making in next periods but it is reasonable than other situations without consideration inflation factor .We define a Fuzzy Multi Objective problem according to maximizing service level and Quality and minimizing Cost of Supply chain and Lead times. Finally a numerical example comes to validate our proposed model in real situations. Results of a computational example suggests that the model can help a manager determine the optimal set of suppliers to employ and make order quantity allocation among them. The use of the proposed model indicates that it can be applicable for improving the group decision making in sharing order among suppliers.