A phrase-structured grammatical framework for transportable natural language processing
Bruce W. Ballard, Nancy Lynn Tinkham · 1984
this paper we present methods of dealing with the syntactic problems that have arisen in the construction of our LDC system. In particular, we shall describe a gram- matical formalism, based on augmented phrase-structure rules, which allows a parser to make domain-specific decisions by referring to a dictionary and other auxiliary files produced during an initial learning session with the user. We illustrate the workings of our grammatical formalism with examples from the existing LDC grammar, but we note that similarly motivated systems ought also to benefit from our formalisms. We will also include the results of some experiments with our existing grammar as applied to several domains. In addition to showing the theoretical advantage of being able to provide many of the fine-tuning capabilities of so-called semantic grammars within the context of a domain-independent grammar, we demonstrate several practical benefits to our approach. For example, the conciseness of our formalism allows shorter grammars than many previous formalisms would allow, at least for the intended class of retrieval applications. This offers not only added perspicuity but other benefits as well. For instance, we have been able to write simple (almost trivial) LISP routines that pre-process a grammar to construct the files used by the parser to increase efficiency and to perform valuable disambiguations