On updating problems in latent semantic indexing

We develop new SVD-updating algorithms for three types of updating problems arising from latent semantic indexing (LSI) for information retrieval to d eal with rapidly changing text document collections. We also provide theore tical justification for using a reduced-dimension representation of the ori ginal document collection in the updating process. Numerical experiments us ing several standard text document collections show that the new algorithms give higher (interpolated) average precisions than the existing algorithms , and the retrieval accuracy is comparable to that obtained using the compl ete document collection.