G. Marchionini, UNC-CH
Latent Semantic Indexing
•Like vector model, use document-term matrix.
•Apply singular value decomposition (SVD) to produce a set of ranked eigenvalues.  These represent abstract concepts in the document space. •Select the top eigenvalues (e.g., first 200) and apply to query-document matching (See Efron dissertation) •Retrieves some documents that may not use the query term