CLIP Colloquium (Fall 2012)

08/20/2012: TopSig – Signature Files Revisited

Speaker: Shlomo Geva, Queensland University of Technology, Australia
Time: Monday, August 20, 2012, 11:00 AM
Venue: AVW 2120

Abstract: Performance comparisons between File Signatures and Inverted Files for text retrieval have previously shown several significant shortcomings of file signatures relative to inverted files. The inverted file approach underpins most state-of-the-art search engine algorithms, such as Language and Probabilistic models. It has been widely accepted that traditional file signatures are inferior alternatives to inverted files. This paper describes TopSig, a modern approach to the construction of file signatures - many advances in semantic hashing and dimensionality reduction have been made in recent times, but these were not so far linked to general purpose, signature file based, search engines. This paper introduces a different signature file approach that builds upon and extends these recent advances. We are able to demonstrate significant improvements in the performance of signature file based indexing and retrieval, performance that is comparable to that of state of the art inverted file based systems, including Language models and BM25. These findings suggest that file signatures offer a viable alternative to inverted files in suitable settings and position the file signature model in the class of Vector Space retrieval models. TopSig is an open-source search engine from QUT and it can be discussed too if there is an interest.

About the Speaker: Associate Professor Shlomo Geva is the discipline leader for Computational Intelligence and Signal Processing in the Computer Science Department at the Queensland University of Technology in Brisbane, Australia. His research interests include clustering, cross-language information retrieval, focused information retrieval, link discovery, and xml indexing.

Host: Doug Oard, oard@umd.edu