TREC-9 Cross Language, Web and Question-Answering Track Experiments using PIRCS

Abstract : In TREC-9, we participated in the English-Chinese Cross Language, 10GB Web data ad-hoc retrieval, as well as the Question-Answering tracks, all using automatic procedures. All these tracks were new for us. For Cross Language track, we made use of two techniques of query translation: MT software and bilingual wordlist lookup with disambiguation. The retrieval lists from them were then combined as our submitted results. One submitted run used wordlist translation only. All cross language runs make use of the previous TREC Chinese collection for enrichment. One MT run also employs pre-translation query expansion using TREC English collections. We also submitted a monolingual run without collection enrichment. Evaluation shows that English-Chinese cross-lingual retrieval using only wordlist query translation can achieve about 70-75% of monolingual average precision, and combination with MT query translation further brings this effectiveness to 80-85% of monolingual. Results are well above median.