Hashing Moving Objects

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In real-life applications, the objects are both spatial and temporal referenced. The objects which continuously change their location are called moving objects. With the development of wireless communication and positioning technology, it becomes necessary to store and index those objects in database. Due to the complexity of the problem, many pure spatial index structures are unable to index large volume of moving objects in database. In this paper, we propose a whole new idea based on hashing technique. Since it is impossible to re-index all the objects after each time period, we store the objects in buckets. When an object moves within a bucket, the database does not make any change. By using this technique, the number of database update is greatly reduced which makes the index procedure feasible. Then, we extend the previous system structure by introducing a filter layer between the position information collectors and the database. Also four different methods based on the new system structure are presented. Performance experiments were performed to evaluate different aspects of our indexing techniques, and the conclusions are included in the paper. Department of Computer Science, University of Maryland