The Preliminary Design And Implementation Of An Urban Traffic Information Distrubution And Guidance System

The system of traffic information distribution and guidance is the important role and the typical application in Intelligent Transporation System. With traffic problems increasing and releated technology developed, Internet based WebGIS becomes the hotspot in overseas and domestic research. Compare to some main WebGIS platforms of overseas and domestic, it's found that the effiency of spatial data processing is decreasing when user quantity increasing. J2EE is deemed to be a potential way to solve this problem. More emphasis is being put on the WebGIS traffic information service system based on J2EE, due to its advantages such as information visibility, widely interoperability, easy to maintain.On the basis of discussing public information distribution, data organization of traffic information is analyzed, time series prediction algorithm and improved A* algorithm based on RTMS data are researched, also an urban traffic information and guidance system based on J2EE is developed by taking Beijing as example. This system makes applications deployed on J2EE platform with high usability, security, expansibility and reliability by using Oracle 10g which is object-related databse as its database server, MapXtreme as map server and EJB encapsulate WebGIS application functions. This system solved the problem of multi-user access concurrently by adopting clusting of J2EE. With managing urban traffic information resource, the system can provide ease-to-use and quick query approaches to obtain urban traffic information for travellers and decision-making departments. It can also provide optimal route by taffic prediction, so as to control traffic dynamically and keep road network in optimal operation.This thesis validates the system's performance by using LoadRunner which is the excellent performance testing tool after functional design and implementation are finished. By concurrent user testing in clustering environment and no-clustering environments, this developed system proved to have preferable support for concurrent users, and show more advantage when user quantity increasing. The system will give much better support for concurrent user with better hardware configuration.The system designed and implemented in this thesis is definitely worthy both from the theoretical and practical application views.