This study proposes a probabilistic model for automatically extracting English noun phrases for indexing or information retrieval. The technique is based on a Markov model, whose initial parameters are estimated by a phrase lookup program with a phrase dictionary, then optimized by a set of maximum entropy parameters. (Author/LRW)

Discusses factors governing the choice between natural and inverted word order in subject headings containing adjectival phrases. (FM)

Describes an information-retrieval schema that takes into account linguistic variation based on phrases. Introduces the phrase-retrieval hypothesis to replace the keyword-retrieval hypothesis, and discusses natural-language processing systems; syntactical, morphological, and lexico-semantical normalization; and future work. (Author/LRW)

This research project was motivated by results of earlier work (Katzer et al., 1982) on the overlap among document representations. In the earlier study, one representation used in the INSPEC database proved to perform unexpectedly well in comparison with other commonly used representations, such as controlled vocabulary or free-text terms from…

Describes the development of an information retrieval system designed for nonspecialist users that is based on the binary vector model. The syntactic structure of phrases used for indexing is examined, queries using an experimental collection of documents are described, and precision values are examined. (19 references) (LRW)