Research For Urban Dynamics Path Guidance System Based On Grid Technology

Recently, Intelligent Transportation System(ITS)is paid more and more attention.The system is the integration of computer technology, communication technology and information technology to transportation.The purpose is to settle traffic congestion, guarantee traffic safety, and raise efficiency of utilization of traffic network. Based on grid technology , a novel road traffic infrastructure referred to a scalable traffic grid is proposed to meet the resource sharing and coordinated use requirements for intelligent traffic system (ITS) development and deployment. A time dependent covariance matrix is designed to quantify such a time-varying correlation relationship between each two individual links.This method is introduced in order to sampling data and reducing the burden of calculation system. The authors integrate traffic density and ant colony algorithm together and apply them to path guidance system. Real-time response time of this system be effectively limited in a scope which may tolerate. The new algorithm makes the system's speed of response and the precision to achieve a balanceIn this paper,we concentrate on some specific portions of PGS:data sampling,improvement of method for filter and analysis,improving on path search algorithm,improvement and design for administration mechanism of grid resource.Some conventional algorithms are improved.Especially,travel times on individual links are mutually correlated in practice, A covariance matrix is designed to quantify such a correlation relationship between each two individual links.By setting the gate value,the sampled data can be selected.furthermore,A measure be provided for dealing with abnormal data.Shortest path is not a optimun path and largely relate to the traffic density ,so the result of new algorithm with introducing traffic density to case shows that it is effective and practicable. In this paper,the authors integrate traffic density and ant colony algorithm together and apply them to traffic guidance system,In addition,put forward new definition of a parameter. The traffic density information is introduced to update pheromone to avoid congestion and to utilize traffic resources effectively.This paper introduces a scalable management mechanism based on policy for grid resource and analyzes correlated key techniques. The contradiction between centralization and distribution has been resolved well by the method of classifying the grid clients and resources points respectively. The Odd Dealer's sharp-edged batch work submittal can be solved by a introduction of resources reservation. This mechanism pays equal attention to the centralization and distribution, and adopts the multi-strategies by combining direct authentication and proxy authentication, thus enhances the grid safe authentication efficiency.