مدیریت موجودی در زنجیره تامین: مشکل چانه زنی

This paper is focused on supply chain management from the perspective of inventory management. The coordination of order and production policies between buyers and suppliers in supply chains is of particular interest. When a buyer of an item decides independently, he will place orders based on his economic order quantity (EOQ). However, the buyer's EOQ may not lead to a favorable policy for the supplier. A cooperative order and production policy can reduce total cost significantly. Should the buyer have the dominant position to impose his EOQ on the supplier, then consequently no incentive exists for him to deviate from his EOQ in order to choose a cooperative policy. To induce the buyer to order in quantities more favorable to the supplier, the supplier could offer a cooperative policy associated by a side payment to the buyer. The research presented in this paper provides several bargaining models depending on alternative production policies of the supplier. With these bargaining models the offered cooperative policy and the offered side payment can be derived.

The term supply chain management refers to cooperative management of materials and information flows between supply chain partners, to reach goals that cannot be achieved acting individually. This paper focuses on the supply chain from the perspective of inventory management. In contrast to multi-echelon inventory management, that coordinates inventories at multiple locations of one company, a joint inventory replenishment policy in supply chains involves coordination among multiple firms (Johnson and Pyke, 2001, pp. 794–795). Therefore, the coordination of order policy and production policy between buyers and suppliers in supply chains is of special interest (Landeros and Lyth, 1989, pp. 146–147). When the buyer and supplier treat inventory problems singly under deterministic conditions, the economic order quantity (EOQ) formula or the economic lot size (ELS) formula gives an optimal solution. However, in general, an order policy based on the EOQ solution is undesirable to the supplier and likewise, a production and delivery policy based on the ELS solution is unacceptable to the buyer (Lu, 1995, p. 312).

In this paper a joint order and production policy is developed as a bargaining solution assuming that the buyer has the dominant position. The paper presents an analytical approach to determining the terms of a supplier-oriented optimal side payment scheme. It is shown that the joint optimal policy with an according side payment results from negotiations. Adopting the bargaining solution, the gain of the supplier depends on his production policy, i.e. if the supplier has the opportunity to use lot streaming or not. With lot streaming the supplier is provided with more flexibility to react on buyer's individual optimal order policy. The supplier realizes a lower cost penalty with lot streaming than without lot streaming. Nevertheless, in both cases, with or without lot streaming, the supplier benefits from the presented bargaining solutions. This raises a crucial practical issue. In order to determine the side payment the supplier must obtain the numerical estimates of buyer's ordering cost per order and buyer's inventory holding cost. While the buyer's periodical demand can be anticipated from the past ordering behavior of the buyer, it is very difficult to estimate buyer's holding and ordering costs. This is true unless the buyer is willing to disclose the true values of his cost parameters (Landeros and Lyth, 1989, p. 313). However, the buyer's holding cost can be specified as an implicit function of his ordering cost and his EOQ and, likewise, the buyer's ordering cost can be specified as an implicit function of his holding cost and his EOQ. The relative insensitivity of View the MathML sourcez=KA(xG)-KA(xA*) to measurement errors permits the establishment of a “good” side payment. Therefore, a bargaining solution succeeds if (P) estimates the cost structure of (A) with sufficient accuracy.