Query expansion techniques for question answering

Abstract

Query expansion is a technique used to boost performance of a document retrieval engine, such as those commonly found in question answering (QA) systems. Common methods of query expansion for Boolean keyword-based document retrieval engines include inserting query terms, such as alternate inflectional or derivational forms generated from existing query terms, or dropping query terms that are, for example, deemed to be too restrictive. In this thesis, I present a quantitative evaluation against a test; collection of my own design of five query expansion techniques, two term expansion methods and three term-dropping strategies. I present results that show that there exist best-performing query expansion algorithms that can be ex- perimentally optimized for specific tasks. My findings pose questions that suggest interesting avenues for further study of query expansion algorithms.