The Application Of Combinatorial Optimization In Supply Chain Management

In recent years,supply chain management has attracted many scholars at home and abroad.The operation costs can be greatly reduced,and the market competitiveness of companies can be greatly improved by the effective management of the supply chain.As an indispensable part of the supply chain management, the inventory management plays an important role in the supply chain management.The theory and methods of operations research and optimization are put into the inventory management and many inventory decision problems which the enterprises encounter in their operation are solved by building mathe-matical models.The theory of optimization is an important part of the operations research.It has been widely applied in many fields.In this thesis,we study the economic lotsizing problems with operations research methods.Our objective is to minimize the inventory cost and the transportation cost by the dynamic programming,and to determine when and how many merchandizes be ordered.Three chapters are included in this thesis.In the first chapter,we describe the research development of the supply chain managements,basic background of the inventory management,some useful information and the main results obtained in this thesis.In the second chapter,we consider a two-echelon dynamic lot-sizing problem about a distribution center and a retailer where the distribution center stipulates a minimum order from the retailer.The aim is to decide the replenishment amount for distribution center and retailer respectively in order to minimize the transportation cost and inventory,cost.The complexity of this algorithm is O(n~5), in which n is the number of periods in whole planning horizon.Finally,we give an example which shows that this algorithm has a good behavior.In the third chapter,we present the dynamic lot-sizing problem with demand time windows and price discounts.Utilizing dynamic programming,we provide an optimal algorithm that runs in O(mT~2) time for the cases of multi-breakpoint N_u(u=1,2,...,m)and demand time window[E_i,L_i](i=1,2,...,n).The subject is to decide the replenishment amount for the retailer in order to minimize the replenishment cost and inventory cost.In addition,a simple example is given to show the effectiveness of this algorithm.