General query expansion techniques for spoken document retrieval

Abstract

This paper presents some developments in query expansion and document representation of our Spoken Document Retrieval (SDR) system since the 1998 Text REtrieval Conference (TREC-7). We have shown that a modification of the document representation combining several techniques for query expansion can improve Average Precision by 17 % relative to a system similar to that which we presented at TREC-7 [1]. These new experiments have also confirmed that the degradation of Average Precision due to a Word Error Rate (WER) of 25 % is relatively small (around 2 % relative). We hope to repeat these experiments when larger document collections become available to evaluate the scalability of these techniques.