Waterloo Experiments for the CLEF05 SDR Track

This year is the first year that the Information Retrieval Group at the University of Waterloo participated in CLEF. For the Cross-Language Spoken Document Retrieval track we submitted five official runs — three English automatic runs (title-only, title+desc, and title+desc+narr), a Czech automatic run (title-only) and a French automatic run (title-only). All official runs used a combination of several query formulation and expansion techniques, including phonetic n-grams and pseudo-relevance feedback expansion over a topic-specific external corpus crawled from the Web. In addition, a large number of un-official runs were generated, including German and Spanish runs. This brief report provides an overview of our experiments, which are summarized in figure 1.