Research On Caching Strategy In Distributed Storage Systems Based On P2P Networks

With the urban transportation situation getting worse and the public transportation strategic priority establishing, the traditional public traffic dispatching system can't meet the higher requirement of passengers for timely and comfortable to public transit. How to utilize the Geographic Information System, vehicle location, digit communication, computer network and other modern scientific technologies to improve the management level of current dispatching and service quality has become an important issue for urban development. Aiming at this issue and combining with our country's actual situation, this paper developed a public transit dispatching management system based on relay wireless communication.The public traffic dispatching system is mainly composed of three parts including the control center, electronic bus stop board and the on-board unit. This paper mainly completes design of the electronic bus stop board and software development of the control center. The part of electronic bus stop board accomplishes the display function of expected arrival time and reliability of the station. Its hardware is designed based on singlechip AT89S52 which is the major component and programmed by C language. The development of control center management platform is started from the analysis of system requirement. It builds up database structure of control center, and uses ADO data memory programming method to achieve customer management, information query, figure display, statistic analysis and bus dispatching and other functions by VC. Meanwhile the database of electronic map is designed, Through wireless communication module of D21DL, the entire system establishes communication networks which applies relay mode to realize the communication of bus, electronic bus stop board and the control center to improve the stability of communication and lower the communication cost.From the result of debugging we can see that the whole system has realized the functional requirements and runs stably and reliably. It is worthy of widely using in the large and medium-sized cities because of the cheap cost and the higher practicability and reliability.