Proposes a probabilistic mechanism to describe various forms of the Bradford phenomenon reported in bibliographic research. The inclusion of a time parameter in the model to allow predictions of dynamic systems is explained. (58 references) (CLB)

Examines the main mathematical approaches to information retrieval, including both algebraic and probabilistic models, and describes difficulties which impede formalization of information retrieval processes. A number of developments are covered where new theoretical understandings have directly led to improved retrieval techniques and operations.…

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…

Presents adaptation of a probabilistic theoretical model previously used in relevance feedback for use in automatic indexing of documents (in the sense of imitating) human indexers. Methods for model application are proposed, independence assumptions used in the model are interpreted, and the probability of a dependence model is discussed.…

Presents and discusses the results of research into similarity measures for search request formulations which employ Boolean combinations of index terms. The use of a weighting mechanism to indicate the importance of attributes in a search formulation is described. A 16-item reference list is included. (JL)

Retrieval experiments with the Cranfield collection of 1,400 documents used strategies based on a probabilistic model for an initial search and intermediate search when no relevant documents were known. Results show initial strategy is better than conventional strategies in retrieval effectiveness and number of queries needed to retrieve…