Utilizing Domain-Specific Information for Processing Compact Text

UTILIZING DOMAIN-SPECIFIC INFORMATION FOR PROCESSING COMPACT TE~T Elaine Marsh Llngulstlc String Project Nee York University Nee York, Nee York ABSTRACT This paper Identifies the types of sentence fragments found In the text of two domains: medical records and Navy equipment status messages. The fragment types are related to full sentence forms on the basis of the elements which were regularly deleted. A breakdown of the fragment types and their distributions In the two domains Is presented. An approach to reconstructing the semantic class of deleted elements In the medical records Is proposed which is based on the semantic patterns recognized In the domain. I. INTRODUCTION A large amount of natural language Input, whether to text processing or questlon-answerlng systems, conslsts of shortened sentence forms, sentence nfragmentsn. Sentence fragments are found in informal technical communlcatlons, messages, headlines, and In telegraphic camunlcatlons. Occurrences are characterized by thelr brev lty and Informational nature. In all of these, if people are not restricted to using complete, grammatical sentences, as they are In formal writing situations, they tend to leave OUt the parts of the sentence which they belleve the reader will be able to reconstruct. Thls is especially true if the writer deals wlth a specialized subject matter where the facts are to be used by others in the same field. Several approaches to such hill-formed,, natural language Input have been followed. The LIFER system [Hendrlx, 1977; Hendrlx, et ai., 1978] and the I~_ANES system [Waltz, 1978] both account for fragments In procedural terms; they Co not require the user to enumerate the types of fragments which will be accepted. The Linguistic Strlng Project has characterlzed the regularly occurring ungrammatical constructions and made them pert of the parsing grammar [Anderson, et el., 1975; Hlrschman and Sager, 1982]. Kwasny and Sondhe!mer (10R1) have used error-handling procedures to relate the Ill-formed input of sentence fragments to well-formed structures. While these approaches differ in the way they determine the structure of the fragments and the deleted material, for the most pert they rely heavily, at some point, on the recognition of semantic word-classes. The purpose of this paper Is to describe the syntactic characteristics of sentence fragments and to lllustrate how the domeln-speclflc Information embodied In the cooCcurrence patterns of the semantic word-classes of a domain can be utilized as a powerful tool for processing a body of compact text, I.e. text that contains a large percentage of sentence fragments, II. IDENTIFICATION OF FRAGMENT TYPES The Nee York Unlversl~y Linguistic String Project has developed a computer program to analyze ccmpact text In special Ized subject areas using a general parsing program and an Engl Ish grammar augmented by procedures speclflc to the subJect areas. In recent years the system has been tailored for computer analysis of free-text medical records, which are characterized by numerous sentence fragments. In the computer-analysis and processing of the medical records, relatlvely few types of sentence fragments sufflced to describe the shortened forlas, a l though such fragments ccmprfsed fully 49% of the …

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