Study On Logistics Distribution Vehicle Routing Problem

With the globalization of economy, modern logistics has became the integrated logistic system that with support of modern science, information technology and management. Logistics distribution plays a very important role in logistics enterprises and it is the key point for increasing the profit. Furthermore, Vehicle Routing Problem is the key problem of logistics distribution. Therefore, it is meaningful to do some research on this problem.Vehicle Routing Problem is a typical NP-hard problem and is difficult to be solved by using pure mathematical methods. With the development of intelligent technology, more and more people begin to use intelligent methods to make scientific decisions and get the optimal solution with less cost or/and more benefits in transportation systems. The Ant Colony Algorithms that based on the research on ant colony is a new method for optimization. It iterates to the best answer according to selective strategy and information element which is generated by each ant.A deep research in theories, methods and models of the present logistics distribution vehicle routing problem is made in this thesis.Firstly, the optimization of vehicle routing problem from standpoints of models analysis and algorithm is studied based on reviewing the actual research status of vehicle routing problem. A detailed discussion on vehicle routing problem models and solution algorithms is given. These models include capacity vehicle routing problem, vehicle routing problem with time windows, vehicle routing problem with customers' satisfaction and stochastic vehicle routing problem.Secondly, after introducing the basic idea, principle and model realization of Ant Colony Algorithm, the algorithm is analyzed and a summary of experiences in the parameter selecting is made in this thesis. Also some typical improved ant colony algorithms are introduced. Furthermore, the traditional ant algorithm has the shortages of tending to go into stagnation behavior and needing longer computing time. Aiming at these shortages, an improved ant colony algorithm is proposed, and then applies it into traveling salesman problem to verify the algorithm. The simulation results show the validity of algorithm.Lastly, an hybrid ant colony algorithm is built to solve vehicle routing problem on the basis of analyzing the similarity and difference between using ant colony algorithm to solve vehicle routing problem and traveling salesman problem. Also routing procedures is programmed and instances are used to verify the algorithm. It shows the feasibility of the algorithm in optimizing the vehicle routing problem through comparing results with congener literatures.