Optimization Study, Based On Third-party Logistics And Transport Cw Algorithm Conservation

with more and more refined distribution of social labor,the supply,the production and the consumption hardly work well in time and space any longer, which resulted in an increasingly important role of the production and the logistics in the social life. The country's economic development is mainly contributed by logistics operators, so governments are making great efforts to develop logistics. Third-party logistics(TPL) is the products of the development of logistics in this society,It also determines the level of development of third party logistics.This thesis is proposed based on the fast development of the third-party logistics ,the key of the most logistics companies is the transport route choose by the vehicle which is usually not reasonable and lead to serious waste of resources.The VRP is a combinatorial optimized problem of the NP-hard, which is unable to solve the problems accurately. This thesis elaborate its basic principles and characteristics in detail with the C.W saving algorithm of heuristic algorithm. The mathematical models of VRP are established with the C.W saving algorithm .They are includes no time windows, single distribution center, various types of vehicles, not overloaded and so on.It is nearly impossible to solve the practical problems with pure theory of heuristic algorithm,so to study the problems of vehicle routing in reality is rather important. In order to meet the actual needs in the transportation and distribution, the C.W saving algorithm is further improved. This thesis builds the mathematical models of vehicle routing with time windows and details the optimized process after considering the problems of flexible time windows,the single distribution center,,the various types of vehicles,the not overloaded,the different types of vehicle with the different road condition and probabilities of cargo damage as well as the different default with different punishment.The mathematical model of VRPTW(vehicle routing problems with time windows) is constructed by applying the improved C.W saving algorithm to specific cases. It designs an infinite punishment when default appeared, which could be explained by the inelastic time window constraints .After optimizing the mathematical model of VRPTW,we get the satisfied results and verify the feasibility and practicability of the improved C.W saving algorithm, and improved the model and algorithm of the VRPTW.