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Stochastic Models for the Distribution of Index Terms.
Peer reviewed Peer reviewed
Nelson, Michael J. – Journal of Documentation, 1989
Presents a probability model of the occurrence of index terms used to derive discrete distributions which are mixtures of Poisson and negative binomial distributions. These distributions give better fits than the simpler Zipf distribution, have the advantage of being more explanatory, and can incorporate a time parameter if necessary. (25…
Descriptors: Goodness of Fit, Mathematical Models, Probability, Statistical Distributions
Inclusion of Relevance Information in the Term Discrimination Model.
Peer reviewed Peer reviewed
Biru, Tesfaye; And Others – Journal of Documentation, 1989
Discusses the effect of including relevance data on the calculation of term discrimination values in bibliographic databases. Algorithms that calculate the ability of index terms to discriminate between relevant and non-relevant documents are described and tested. The results are discussed in terms of the relationship between term frequency and…
Descriptors: Algorithms, Automatic Indexing, Bibliographic Databases, Mathematical Models
A Zipfian Model of an Automatic Bibliographic System: An Application to MEDLINE.
Peer reviewed Peer reviewed
Fedorowicz, Jane – Journal of the American Society for Information Science, 1982
Derives the underlying structure of the Zipf distribution, with emphasis on its application to word frequencies in the inverted files of automatic bibliographic systems, and applies the Zipfian model to the National Library of Medicine's MEDLINE database. An appendix on the Zipfian mean and 12 references are included. (Author/JL)
Descriptors: Citations (References), Databases, Information Retrieval, Mathematical Models
Term-Weighting Approaches in Automatic Text Retrieval.
Peer reviewed Peer reviewed
Salton, Gerard; Buckley, Christopher – Information Processing and Management, 1988
Summarizes the experimental evidence that indicates that text indexing systems based on the assignment of appropriately weighted single terms produce retrieval results superior to those obtained with more elaborate text representations, and provides baseline single term indexing models with which more elaborate content analysis procedures can be…
Descriptors: Automatic Indexing, Comparative Analysis, Content Analysis, Information Retrieval
Applying Informetric Characteristics of Databases to IR System File Design, Part I: Informetric Models.
Peer reviewed Peer reviewed
Wolfram, Dietmar – Information Processing and Management, 1992
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)
Descriptors: Computer System Design, Database Design, Databases, Foreign Countries
Applying Informetric Characteristics of Databases to IR System File Design, Part II: Simulation Comparisons.
Peer reviewed Peer reviewed
Wolfram, Dietmar – Information Processing and Management, 1992
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)…
Descriptors: Analysis of Variance, Comparative Analysis, Computer Simulation, Computer System Design