Research On Integrated Optimization Of Inventory And Routing Problem Under VMI

With the development of information technology and economics globalization, the competition among enterprises has moved to the competition among supply chaines. Vendor Managed Inventory (VMI) has been adopted broadly under this new marketing environment. VMI breaks the traditional inventory mode in which each member does things in their own ways, provides a new chance for suppliers to overcome the "trade-off" problem between transportation and inventory, and reduces logistics costs by means of whole plan of transportation and inventory, with systemic and integrated inventory management. The IRP problem studied in this paper will be integrated and optimized by the method of management operations method, through focusing on both inventory and transportation logistics sectors.Firstly, the paper reviews the research results on inventory routing problem home and abroad, sums up the inventory routing problem solving model and calculations in recently years, basing on a summary of a large number of relevant literatures. Through studying the inventory and routing problem under VMI model, analyses and builds a one-to-many two-tier distribution system of inventory routing model; assumes that the system processes a single product, at the same time taking into account the distribution center and retailer inventory holding costs; the goal of the model is to minimum the total system cost, which includes transportation costs, inventory costs and stock loss. And the transport cost includes the fixed cost per delivery and distribution and variable costs related to distance.In solving the model, firstly, the paper determines which retailer and how many needs to delivery to them in the cycle, according to the retailer's initial inventory and demand, also the inventory costs of the delivery system can be gotten; secondly, the paper determines the vehicle routing, transportation costs and also the costs stock loss, through the improved simulated annealing algorithm; finally, to get the approximate optimal solution, optimizing the initial solution through changing the retailers'delivery time.Finally, the paper builds an example to test the model, using the MATLAB7.0 software, and the test result shows that the model and the algorithm designed in this paper are feasible.