Estimate Validity Regions for Nearest Neighbor Queries

Users’ queries for data or services in a mobile computing environment are highly relevant to their current locations. A nearest neighbor (NN) query finds the data object closest to the user’s location; and hence, NN query issued at different locations may lead to different results. The nearest neighbor validity region (NNVR) is the area where an NN query result remains valid. A cached NN result can be used to answer semantically equivalent NN queries issued in the same NNVR. Our analysis discovers that NNVRs carry useful information about neighboring objects’ locations. This paper proposes an algorithm data mining the hidden information in cached NNVRs to increase the proxy caching performance. The experimental results and analysis have demonstrated the effectiveness of the proposed algorithm in reducing query response time and workload on the database server.