Discussion of a new method of index term dictionary compression in an inverted-file-oriented database highlights a technique of word coding, which generates short fixed-length codes obtained from the index terms themselves by analysis of monogram and bigram statistical distributions. Substantial savings in communication channel utilization are…

Describes the development of a structural model of document retrieval based on lexical-semantic relationships between index terms. An algorithm that uses tree-to-tree distance to measure structural closeness between a document and a query statement is explained, and the proposed model is compared to a vector retrieval model. (18 references) (LRW)

Examines the use of various statistical techniques for generating domain-oriented multiword vocabulary terms for natural language database systems. Conclusions show the vocabulary clustering effect should be considered when making significance calculations and that a simple ratio of subject matter relative frequency to total sample relative…

Describes technique developed as automatic support to subject heading indexing at BIOSIS based on use of formalized language for semantic representation of biological texts and subject headings. Language structures, experimental results, and analysis of journal/subject heading and author/subject heading correlation data are discussed. References…

Describes a study that analyzed the Medical Subject Headings (MeSH) terms used to index the literature of Acquired Immunodeficiency Syndrome (AIDS). Subject access to the AIDSLINE database developed by the National Library of Medicine (NLM) is examined, and changes in subject headings that reflect the growth of the field are analyzed. (12…

Describes fast, dynamic update algorithms for document retrieval systems. B-trees are discussed; the M-B-T file directory structure is explained; insertions and deletions in inverted files are described; and performance evaluation is discussed. An appendix provides the formal definition of an M-B-T directory. (Contains 18 references.) (LRW)

Examines how informetric characteristics of information retrieval (IR) system databases can be used to help system designers decide what type of file structures would provide the best performance. The development of appropriate models describing database contents is highlighted in this first part of a two-part study. (30 references) (LRW)

Presents a method for using the amount of semantic information in search-query terms as a weighting factor in constructing a fuzzy relation of resemblance between retrieved items in information retrieval online. Two tables, two figures, and a reference list accompany the text. (Author/JL)

This second report on a two-part study on the application of informetrics to information retrieval (IR) system design used models of database contents in a factorial simulation study at the University of Western Ontario. The study explored whether different file structures were better suited for different informetric environments. (32 references)…

Estimates of frequency of spelling errors are made based on a sample of 3,600 index terms drawn from 11 bibliographic data bases. The impact of these errors is discussed by tape supplier, tape user, and end user; with some suggestions for search strategies.

Proposes a conceptual reference architecture for information retrieval systems and discusses functional capabilities of a hypertext environment, based on the proposed architecture, for interaction with large textual databases. Functions of the prototype system HYPERLINE are described, and an example of a user session is provided. (17 references)…

Describes a method based on Bayesian networks for searching hypertext systems. Discussion covers the use of Bayesian networks for structuring index terms and representing user information needs; use of link semantics based on constrained spreading activation to find starting points for browsing; and evaluation of a prototype system. (64…

Describes a study that tested the effectiveness of a thesaurus as a search-aid in free text searching of a Finnish full text database. Linguistic and conceptual approaches are discussed; five search modes are explained; recall and precision are examined; and the use of proximity operators is discussed. (Contains 29 references.) (LRW)

A hypertext-based thesaurus is proposed as a navigational aid to the subject domain of a bibliographic database. Implementation of a hypertext version of the "Thesaurus of ERIC Descriptors" with database linking strategies is discussed. (44 references) (EA)

This discussion of the structure of online databases and the structure of related subject disciplines focuses on terms used in a book about tropical diseases and terms used in the MEDLINE database for articles on these diseases. Matrices used are explained and Medical Subject Heading (MeSh) terms are examined. (16 references) (LRW)