Research Of Lanzhou Intelligent Transport Information-Integrated System And The Shortest Path Problem

Countries around the world are handling traffic problem. The busy traffic wastes time and intensifies environmental pollution, intengent transport system is the one that can deal with the problem. Zhou intelligent transport system (LZ-ITS) used many advanced technologies, such as automation technology, computer science technology, and artificial intelligence technology. Under the support of network and DBMS, LZ-ITS integrated traffic activities of Lanzhou in order to improve the efficiency of traffic management. It means a lot for improving traffic order and reducing the number of traffic accidents.The designing and developing activities are all conducted by the method of software engineering, and the B/S and C/S hybrid structure is imported into the system structure. Meanwhile, in order to avoid Servlet becoming biger with the numbers of request, this paper proposes a new framework based on Servlet.The system is composed of three modules, data-collecting module, data-analyzing module and publishing information module. Data-analysis module analyses data that provided by data-collecting module and its results are published by information publishing module.Besides, the priority of this paper is to research A~* algorithm that is used to solve the shortest path problem. Because the classical algorithm can't get the anticipated result when the traffic restrictions exist in road network, so that the improving work needs to be done. The work including two steps, the first step is mainly focused on the shortcoming of classical A~* algorithm. Finding the optimal solution under the traffic restriction by expanding the sub-nodes according to the restriction, in order to make sure that the final result doesn't include the path that is not accessible. The second step is mainly focused on the speed of the improved A~* algorithm, improving the speed of algorithm by finding weight through testing method in terms of admissibility. Putting the new heuristic function into the algorithm, the fewer nodes are expanded and the less time is spent.