Distribution Logistics Carpool Line Optimization

Modern logistics, which is called the third source of profit, has been cared by all of the world. With the development of our country's economy, advancing the development of modern logistics and the logistics management and the progress of the logistics technology become more and more important part of the development of our society economy now. As the development of "third-party logistics(TPL)", distribution is becoming more and more important, which is a special and compositive logistics activity.How to institute the plan of distribution and choose the distribution route are the most difficult problems in the distribution activities. By this time accuracy algorithm and heuristic algorithm had been tried. But these two kinds of algorisms all exist very big shortage in physically applied. Therefore effectively solving the two problems become the urgent request.In this paper attention is fixed on optimizing the route of distribution by less than container load. Taking mathematics model as a tool to describe the problem, with network simplex method and lagrangian relaxation and heuristic method for main research method, a approximate solution can be gotten. Thus the problems are well solved.Firstly the situation of current physical distribution(PD) is summarized in this paper. Then a mixed integer programming model with the goal of minimizing the delivering cost is built, afterward the optimal solution of the model and whatcondition the solution should satisfy is analyzedIn consideration of the complexity of the problem, to solve its optimal solution is physically useless. We fix attention on how to get its approximate solution. Network simplex method is an effective method to solve network flow problem and lagrangian relaxation is one of the very few solution methods in optimization that cuts across the domains of linear and integer programming, combinatorial optimization, and nonlinear programming. In this paper we get the lower bound of the primal problem by network simplex method together with lagrangian relaxation. Furthermore we can get a feasible solution as the upper bound of the primal problem by heuristic method together with the lower bound. We iterate the process again and again to reduce the scope of the upper and lower bound until we get an approximate solution which is available.In this paper, an example is given to test our algorithm and the operation process is given through a table. At last we expatiate the actual value of the application of the model which explain our algorithm can effectively solve that how to institute the plan of distribution and choose the distribution route.