Posting Compression in Dynamic Retrieval Environments Posting Compression in Dynamic Retried Environments

This paper describes a posting compression technique to be used in dynamic full-text document retrieval environments. The compression technique being presented is applicable in main-memory document retrieval systems, and consists of two parts. First there is the efficient use of auxiliary tables, and second there is the application of the well-known rank-frequency law of Zipf. It is shown that on the basis of this law term weights can be approximated, and thus that their explicit storage can be avoided. The underlying retrieval model being used is the vector space retrieval model, from which it is already known that it guarantees a high retrieval quality. Prior to our compression results, in this paper we also present some minor modifications to the vector space retrieval model, improving its quality slightly.