A Study Of Optimal Order Policy For Perishable Items With Permissible Delay In Payments

Inventory control is an important part of the operations research. It has a profound practical background and broad application prospects. It is widely used in computer systems, social science, engineering design and modern management and so on. For the present, it has become a very active branch of operational research. New inventory models for perishable items is developed in a two-item system in the condition that shortage is not admited, not backlogge or fully backlogge. The two-item system is a system that a supplier permits a retail to pay for his ordering stock after a fixed period, but the retailer permits his customer to pay partially for his shopping goods after a fixed period. By analyzing the models, we show solution methods and numerical experiments. Three chapters are included in this thesis.In chapter 1, the evolution history and application background of inventory control are introduced, then the relevant definitions and knowledge are involved. At last, the main results of the article are summarized.In chapter 2, a new inventory model for perishable items with partial permis-sible delay in payments is developed in this paper. By characterizing the model, we prove the existence of the optimal order policy and give a solution method. The given numerical experiments show the sensitive analysis of parameters to the developed model.In chapter 3, by relaxation the assumption in the last chapter, consider the affect of retail's inventory in a two-tier system of delay in payment in the shortage condition. By analyzing the retail's earnings, two new models for perishable items are developed when shortage is not backlogge or fully backlogge. This chapter analyzes the models simply.