بهینه سازی سود زنجیره تامین کل در برابر منافع خریدار از طریق انتخاب تامین کننده

A number of mathematical models have been developed for modeling the supplier selection problem. Most of these models have considered the buyer's viewpoint and maximized only the buyer's benefit. This does not necessarily lead to an optimal situation for all members of a supply chain. Co-ordination models have been presented to optimize the benefits of all the members and alignment of decisions between entities of a supply chain. In this paper, the issue of coordination between one buyer and multiple potential suppliers in the supplier selection process has been considered. On the other hand, in the objective function of the model, the total cost of the supply chain is minimized rather than only the buyer's cost. The total cost of the supply chain includes the buyer's cost and suppliers’ costs. The model has been solved by applying mixed-integer nonlinear programming. Finally, the proposed method is illustrated by a numerical example.

Recently, many researchers have paid attention to total optimization in the supply chain. In the supply chain literature, two types of optimization have been defined: local optimization and global or total optimization. Local optimization of each member does not guarantee optimization of the total supply chain. In total supply chain optimization, all members of a supply chain attempt to maximize a chain's revenue or minimize the cost of a chain in close collaboration with each other. Total optimization is very complex because of the large numbers of the supply chain's members and difficulties in their relationships. Narasimhan and Carter (1998) in their paper have presented that a well-integrated supply chain involves coordinating the flows of materials and information between suppliers, manufactures, retailers and any other intermediaries. Thomas and Griffin (1996) have stated that to achieve effective supply chain management, planning and coordination among all entities in a supply chain is needed. Several models such as quantity discounts, credit option and buy-back/return policies are applied to align and coordinate the decisions between members of a supply chain. Most of these models are used to improve the effectiveness of an existing supply chain. When a supply chain is being designed and structured, the coordination and alignment of decisions between entities are of great importance. Supplier selection and order allocation problems are the primary subjects that must be considered in the beginning of a supply chain design. Many papers have been published to develop models in this field. Most of these models have considered and optimized only a buyer's objectives without respect to suppliers’ utilities. In these models, suppliers offer their conditions such as production constraint, sale prices and discounts, and the buyer selects the right suppliers in the light of his optimal situation and allocates orders to them. Here, the buyer's bargaining power impels suppliers to accept and follow his decisions. This paper develops a supplier selection and order allocation model to minimize the average total cost incurred in the whole supply chain. Furthermore in this paper, a model is generated to coordinate decisions between buyers and suppliers in a supplier selection process. The remaining part of this paper is organized as follows. In Section 2, previous studies are reviewed. In Section 3, a single-objective supplier selection model and its solving algorithm are presented. In Section 4, a numerical example is illustrated. Finally, in Section 5, results and future research directions are presented.