Transforming range queries to equivalent box queries to optimize page access

Abstract

Range queries based on L 1 distance are a common type of queries in multimedia databases containing feature vectors. We propose a novel approach that transforms the feature space into a new feature space such that range queries in the original space are mapped into equivalent box queries in the transformed space. Since box queries are axes aligned, there are several implementational advantages that can be exploited to speed up the retrieval of query results. For two dimensional data the transformation is precise. For greater than two dimensions we propose a space transformation scheme based on disjoint planer rotation, and along with pruning query box the results are precise. Experimental results with large synthetic databases and some real databases show the effectiveness of the proposed transformation scheme. These experimental results have been corroborated with appropriate mathematical models.