Study On The Inventory Routing Problem Based On R-System And Dr-System

It has long been recognized that efficient management of the supply chain (SCM), which is concerned with procurement, storage, movement and distribution of materials, is very critical for achieving superior performance for a business. Two of the significant components of the supply chain ate inventory and transportation. Traditionally, management science models have studied inventory control and transportation problems independently, ignoring the effect of one decision on the other. As a result, most suppliers focus only on the individual elements of the supply chain (such as inventory, assembly, and delivery routes) independently of each other with the intent of reducing the cost of the individual elements. The resulting overall solution (that is, the combination of these independent solutions) can be decidedly sub-optimal, since independent decisions fail to consider the interactions in the supply chain. Hence, in many situations, there is a need to integrate the components of the logistics, especially the inventory and transportation.The inventory routing problem (IRP) addresses the coordination of inventory replenishment and transportation. At present, there are more researches on Inventory Routing Problem (IRP) in developed countries, since they are paying much attention to Supply Chain Management. While in China, however, whether the research on IRP or the application in the logistics strategies involving inventory control and transport routing appear weak in current rapidly developing logistics research and practice. Consequently, this paper is meant to discuss IRP theoretically, and illustrate the conclusion of discussion in practice. In order to achieve this goal, this paper arranges contents as follows.In the first place, in order to develop an understanding of IRP, this paper introduces its research background, theoretical and practical significance. In addition, we research the inventory routing problem based on Retailer System and Depot and Retailer System respectively.As far as the IRP basing on R-System is concerned, this paper researches this problem from a new aspect. The objective of this problem is to determinethe minimum number of vehicle, which should be acquired to service the customers. Distribution center determine the fleet size not only to satisfy the delivery service, but also to reduce the transportation cost. So the problem is to coordinate the relationship among the fleet size, cost and service quality. This paper design a heuristics save algorithm to decide the delivery route, frequency and the number of product delivered to the customer.While to the IRP basing on R-System, this paper divides the problem to two sub-problems, that is distribution center's ordering problem and delivery problem. First, solve the ordering problem, and then use this result to resolve the delivery problem, not concerning the impact of coordinating distribution center and customer delivery problems. So we obtain the initial feasible solutions to the IRP problems. Second, analysis how the distribution center's ordering decisions are affected if the delivery schedules for customers are changed. In other words, the paper estimates the benefits of integration in terms of cost reduction over the case when the distribution center and customer decisions are made independently. We adopt the change, which leads to the greatest reduction in the overall costs. This process is repeated until we reach the stage where there is no further gain by coordinating the two decisions, and that is a satisfying solution to the problem.Finally, as far as stochastic inventory routing problem is concerned, this paper proposed the way to make the customer's demand determined by using the typical "newsboy problem". Of course ,this paper also take the risk into account. Then we can resolve the stochastic IRP by translating it into the determined IRP.