Research On Composition And Evolution Of Grid Service And Their Application In Traffic

Nowadays, the Internet-based integrated transportation platform becomes the focus of urban transportation system research, with the purpose of widespread resource sharing and coordination. Traditional software technology system can't meet the challenges of urban transportation system effectively, with complexity, distribution and heterogeneous characteristics, which becomes the bottleneck in its development. This thesis introduces the grid technology to the research and practice of urban transportation system and research some methodology for the development the Urban Transportation systems.The methodologies of the composition and grid service Dynamic evolution for urban transportation systems are presented in this paper. Firstly, the development methodologies of the traffic grid service were researched and presented. Secondly, with the grid technology increasing used in the traffic area, the composition of traffic function service is main method. The layered composition architecture named HGSDR is presented in this paper. In this architecture, the Portal only interacts with the user and the coordination and schedule of the task are controlled by the Engine service. Engine services are responsible for finding the optimal adjacency service node and monitor the executing procedure. The architecture presented in the paper not only removes the bottleneck of the Portal for centralized scheduling but also improves the reliability and flexibility of system. Finally, due to the lack of ability for service dynamic evolution in the complicated transportation system, the method for the service dynamic evolution is presented in this paper. The connector service is introduced to the method to further eliminate the dependency between the function service and responsible for the interaction of the service.The research show that the composition and evolution of traffic application system based on Grid can greatly satisfy the demands of urban traffic system and has a constructive contribution to other fields adopting grid technology.