language: en

Realistic Parsing: Practical Solutions of Difficult Problems

SYLVAIN DELISLE a & STAN SZPAKOWICZ b
a Département de mathématiques et dinformatique Université du Québec à Trois-Rivières
Trois-Rivières, Québec, Canada G9A 5H7
email: Sylvain_Delisle@uqtr.uquebec.ca,

[phone +1 819 376 5125; fax +1 819 376 5185]

b Department of Computer Science University of Ottawa
Ottawa, Ontario, Canada K1N 6N5
email: szpak@csi.uottawa.ca,

[phone +1 613 562 5800 ext. 6687; fax +1 613 562 5187]

Abstract This paper describes work on the linguistic analysis of texts within a project devoted to knowledge acquisition from text. We focus on syntactic processing and present some key elements of the projects parser that allow it to deal successfully with technical texts. The parser is fully implemented and tested on a variety of real texts; improvements and enhancements are in progress. Because our knowledge acquisition method assumes no a priori model of the domain of the source text, the parser relies as much as possible on lexical and syntactic clues. That is why it strives for full syntactic analysis rather than some form of text skimming. We present a practical approach to four acknowledged difficult problems which to date have no generally acceptable answers: phrase attachment; time constraints for problematic input (how to avoid long and unproductive computation); parsing conjoined structures (how to preserve broad coverage without losing control of the parsing process); and the treatment of fragmentary input or fragments that are a byproduct of a fallback parsing strategy. We review recent related work and conclude by listing several future work items.

Key Words Text processing, knowledge acquisition from text, broad-coverage parsing, parsing conjoined structures.

1. Introduction