Fragmentation and Part of Speech Disambiguation

FRAGMENTATION AND PART OF SPEECH DISAMBIGUATION l Jean-Louis Binot BTM. Kwikstraat, 4 B3078 Everberg, Belgium ABSTRACT That at least some syntax is necessary to support semantic process- ing is fairly obvious. To know exactly how much syntax is needed, however, and how and when to apply it, is still an open and crucial, albeit old, question. This paper discusses the solutions used in a semantic analyser of French called SABA, developed at the Uni- versity of Liege, Belgium. Specifically, we shall argue in favor of the usefulness of two syntactic processes: fragmentation, which can he interleaved with semantic processing, and part-of-speech disambiguation, which can be performed as a preprocesslng step. 1. Introduction The role of syntax is one of these issues in natural language proc- essing which, albeit old and often (hotly) debated, have yet to re- ceive a definitive answer. (Lytinen 86) distinguishes two approaches to NI, processing. Followers of the "modular" approach believe usually in the autonomy of syntax and in the usefulness and cost- effectiveness of a purely syntactic stage of processing. Results of this approach include the development of new grammatical formalisms (Weir et al. 86) (Ristad 86), and of large syntactic grammars (Jensen et al. 86). Followers of the "integrated" approach, on the contrary, believe that semantics should be used as soon as possible in the parsing process. An "integrated" system would have no discemable stages of parsing, and would build directly a meaning representation with- out building an intermediate syntactic structure, tlow much syntax is needed to support this semantic processing, however, and how should the integration between syntax and semantics be done are still open and crucial questions. Some integrated systems, such as IPP (Schank et al. 80) and Wilks" Preference Semantics system (Wilks 75), were trying to reduce the role of syntax as much as possible. Lytinen proposes a more moderate option in which sepa- rate syntactic and semantic rules are dynamically combined at parsing time. Another kind of integration is used in (Boguraev 79), where an ATN is combined with Wilks' style semantic procedures. And, lastly, one might consider that unification-based grammars (Shieber 86) offer yet another approach where syntactic and se- mantic constraints can be specified simultaneously in functional structures and satisfied in parallel. The research presented in this paper was entirely performed while the author was working at the Computer Sciences department of University of Liege, Belgium. In this paper, we wish to present our arguments in favors of in- tegration, and then to discuss two specific technical proposals. Our general position can be stated as follows: 1. That at least some form of syntax is necessary for natural lan- guage processing should be by now fairly obvious and should need no further argumentation. 2. Syntax, however, is not a goal per se. The basic goal of NLP, at least from the point of view of AI, is to give a computer a way to "understand" natural language input, and this dearly requires a semantic component. The utility or …

Content truncated to 500 words