Transportation Network Moving Objects And Implementation Of The State Index

With the rapid development of technologies such as mobile computing, GPS, wireless communication, location-based services get more and more attention, so checking the location of moving objects has become feasible and necessary. In the transport network, the location of moving objects will be updated to moving object database and the database can store and manage effetely the location of the moving objects. To achieve efficient query on moving objects, moving object indexing technology emerges. It can rearrange and manage the data of the moving objects, and provide accurate location inquiry, so the research of it in the mobile database has important research and commercial potential.Based on introducing the technology of spatio-temporal database and moving objects index, this article analyzes the index of moving objects technology in the transport network. First, model the traffic network and convert the reality road into diagram in the two-dimensional; analyze the usual spatio-temporal model of moving objects. Though the analysis of the index technologies of moving objects and the research of application demand of objects moving on limited road network, a index structure of FNR*-Tree is proposed which can index the location of objects moving on transport network in the past, present and future time. FNR*-Tree is composed of 2DR-Tree, 1DR-Tree and HASH table, which 2DR-Tree is used to index the space of road network. The whole space is divided into multi-level sub-index space. According to the spatial division, the leaf nodes contain road segments which are corresponding to an 1DR-Tree. Meanwhile the same segments of a road connect each other through pointers in 2DR-Tree to achieve the road inquiry.1DR-Tree manages the objects moving on a road segment in accordance with the time attributes. With the moving objects constantly leave the road, the information of moving objects constantly inserts in 1DR-Tree. HASH structure is composed of a HASH table and a dynamic list. HASH table stores identifies of moving objects and each object points to a dynamic list. List stores the moving information of moving objects in a chronological order. Based on the analysis of the moving rule of objects in the transport network, with FNR*-Tree trajectory prediction models are proposed for objects moving on suburban and urban areas which can answer the query that is between two update time or after the last update time, which can index the moving objects in full-time. According to the index structure of moving objects in transport network, analyze the usual update strategy and propose a dynamic update strategy that is suitable for FNR*-Tree which updates from bottom to middle.Using the performance of node accesses as a reference for performance comparison of FNR*-Tree index structure and the FNR-Tree indexing methods, the results show that the full-time index structure for objects moving on transport network has a performance improvement on dynamic update, window query, point query, especially on trajectory and can track moving objects with high accuracy.