David Cabrero Souto

Dynamic programming as frame for efficient parsing

The last few years have seen a renewal of interest in the consideration of dynamic programming in compiler technology. This is due to the compactness of the representations, which are turning this paradigm into a common way of dealing with highly redundant computations occurring, for instance, in natural language processing, logic programming or abstract interpretation and related to phenomena such as non determinism or domain ordering. However, it is not usual to find practical studies about what the real interest of these techniques is, and which approaches are better adapted in each case. We justify the consideration of dynamic programming, both in definite clause and context free grammar parsing, highlighting the parallelism between the conclusions reached in both cases. We focus on the computational properties, suggesting a simple decision guide for the reader interested in applying this technology.

COLE experiments at QA@CLEF 2004 spanish monolingual track

This paper is a report on our third participation in CLEF. More precisely, this year we have participated in the Spanish Monolingual Question Answering Track for the first time. As a result we have developed a prototype of a QA system. Our prototype continues to apply the Natural Language Processing techniques we had already developed for single word conflation. In addition, the question analysis is based on complex pattern matching either over forms, part-of-speech tags or lemmas of the words involved. Regarding the search for relevant parts of documents containing the required answer, we use conventional IR techniques, whilst the extraction of the answer from the relevant parts of documents is again based on pattern matching.