This analysis of Zipf's law uses an index for the sequence of observed values of the variables in a Zipf-type relationship. Three important properties relating rank, count, and frequency are identified, shapes of Zipf-type curves are described, and parameters of the Mandelbrot-Zipf law are discussed. (Author/LRW)

Describes the two basic approaches to the calculation of term discrimination values for automatic indexing. The results of an experiment that investigated the differences between algorithms of these two approaches in terms of their impact on the discrimination value model are reported and discussed. (13 references) (Author/CLB)

Describes three models for probabilistic indexing, all based on the Darmstadt automatic indexing approach, and presents experimental evaluation results for each. The discussion covers the improved retrieval effectiveness of probabilistic indexing over binary indexing, and suggestions for using this automatic indexing method with free text terms.…

Outlines an approach to the automatic construction of a knowledge base resulting in a system that is able in each phase of its construction to acquire domain knowledge from all new information that it is building, particularly index terms. Topics covered include production rules, the use of semantic networks, and user interfaces. (32 references)…

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…

Discusses methods of weighting of descriptors in document search patterns together with the concept of relative indexing and conditions which should be satisfied by descriptor weight. A procedure for modifiying document search patterns based on users' informational needs and opinions is outlined, and examples are given. Sixteen references are…

Presents an analytical approach to the interpretation of weighted Boolean queries. By distinguishing query term weights from query weights, a query becomes a means of describing classes of ideal documents and expressing relativity criteria among these descriptions. A formalization of query term weights is given in a fuzzy set theoretical context.…

Provides a method for estimating precision without examining individual database documents, which requires knowledge of only the query or expressed information need and a set of database parameters constant for all queries. Concepts of historic and expected precision are examined, and applications of precision-document graphs are assessed. (36…

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)

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)…