Research On Inventory Routing Problem Based On Fixed Partition Policy

The research content of this paper comes from the National Natural Science Foundation (70771034).Inventory routing problem researches inventory problem and transportation problem in two-echelon supply chain system. The products are delivered to the retailers by a fleet of vehicles with limited capacity. IRP can be used in different stages of supply chain management. It can improve the performance of the system performance and reduce the cost of supply chain.For a two-echelon supply chain system made of single-supplier multi-retailer, the paper separately studies power-of-two and integer-ratio policies in integrated supply chain, studies coordination problem in non-integrated supply chain.For an integrated two-echelon supply chain system, the paper firstly designs a region partition algorithm for the retailers. We extend traditional power-of-two replenishment interval strategy which one region one interval, and design a different replenishment interval policy in the same region. By this way, the cost of the whole supply chain was reduced. Secondly, the paper compares the replenishment interval between retailers and the supplier. By using interval ratio vector we design a new integer-ratio policy. With a particular theoretical analysis, it is proved that this strategy is the optimal one.For a non-integrated two-echelon supply chain system, by compared the cost between individual order and united order, we know the necessity of coordination, and use quantity discount mechanism to coordinate the whole supply chain.Numerical experiment verifies the effectiveness of the above policies in dealing with inventory routing problem.