Improving Space-Efficiency in Temporal Text-Indexing

Support for temporal text-containment queries is of interest in a number of contexts. In previous papers we have presented two approaches to temporal text-indexing, the V2X and ITTX indexes. In this paper, we first present improvements to the previous techniques. We then perform a study of the space usage of the indexing approaches based on both analytical models and results from indexing temporal text collections. These results show for what kind of document collections the different techniques should be employed. The results also show that regarding space usage, the new ITTX/VIDPI technique proposed in this paper is in most cases superior to V2X, except in the case of patterns of high number of new documents relative to number of updated documents.