A Survey of Query Expansion until June 2012
Yogesh Kakde · 2012
Here we present a survey of important work done on Query Expansion (QE) between the period 1970 to 2012. Queries formed by search engine users, are generally short and vague. It is very dicult to estimate the exact user need. Sometimes, the queries are well formed and clear, but the document collection does not contain the information in the same form as that of the query. Synonymous terms or related terms are present in the collection. Query expansion adds terms to the original query, which provides more information about the user need. There are various approaches to query expansion. Some of them use lexical resources or dictionaries for query expansion. Lexical methods cause more damage through topic drift. Relevance feedback approaches perform better than lexical approaches, but they depend on the performance of initial retrieval. In recent years Wikipedia is being used as an external knowledge source for QE. In this survey we cover important work done using all these approaches.