Describes an information retrieval methodology based on relevance weighting of search terms in pairs of documents. The vector space model of information retrieval is reviewed, the Bayesian model of text retrieval is discussed, and an automatic implementation of weight estimation using the Medline database is described. (16 references) (LRW)

Discusses use of associative search techniques and theoretical approaches to document retrieval problems contrasting two different ways of improving system performance: appending associative search techniques to conventional document retrieval systems and designing document retrieval systems based on probabilistic design principles. Four…

Discusses term weighting formulae and their use for selecting new terms to enhance a search statement and for weighting the terms for retrieval purposes once selected. The Swets model of information retrieval system performance is described, an approach to term selection is presented, and future research is suggested. (five references) (LRW)

Describes a theoretic process to apply Bahadur-Lazarsfeld expansion (BLE) to general probabilistic models and the state-of-the-art 2-Poisson model. Through experiments on two standard document collections, one in Korean and one in English, it is demonstrated that incorporation of term dependences using BLE significantly contributes to performance…

Reports on two experiments investigating the relationship between topical subject expertise and the assessment of relevance. Results indicate that topical subject expertise enhances effects of the semantic distance model (SDM), and that relevance assessment is a contingent, psychological phenomenon that is part of the human-perception task of…

Explains how a competition-based connectionist model for diagnostic problem-solving is adapted to information retrieval. Topics include probabilistic causal networks; Bayesian networks; the neural network model; empirical studies of test collections that evaluated retrieval performance; precision results; and the use of a thesaurus to provide…

Presents information retrieval design approach in which queries of computer-based system consist of sets of terms, either unweighted or weighted with subjective term precision estimates, and retrieval outputs ranked by probability of usefulness estimated by "maximum entropy principle." Boolean and weighted request systems are discussed.…

Formulates a model to accommodate the hypothesis that, if the content representation items of documents in a database are neither totally independent nor highly correlated, combining them in a certain way may increase information retrieval effectiveness. The results of a small experiment that tested this hypothesis are presented. (Author/JD)

Describes the three subsystems of an information retrieval system (document descriptions, queries, and matching algorithms) and argues that the interdependency of these subsystems requires adaptation for the system to perform when any component changes. An algorithm for redescribing documents, in response to changes in queries and retrieval rules,…

Presents a set-oriented view of information retrieval and defines a precise model to capture this approach. A number of consequences of the model, such as the limitations implied by a finite index vocabulary, are examined, and the various ways in which the set orientation can influence thinking about information retrieval is discussed. (14…

Relative effectiveness of indexing using full-text or less than full-text was tested using non-Boolean, chaining type of file structure and searching method. Indexing was done using titles, abstracts, full-text, references, and various combinations; Goffman's indirect method of information retrieval was used to structure and search file.…

Describes the Belief Function Model for automatic indexing and ranking of documents which is based on a controlled vocabulary and on term frequencies in each document. Belief Function Theory is explained, and the Belief Function Model is compared to the Standard Vector Space Model. (17 references) (LRW)

Discusses an experiment with the "Thesaurus of ERIC Descriptors" which aimed to adapt established criteria for the evaluation of information retrieval systems to the assessment of searcher performance in online bibliographic searching. The concept of relevance is discussed, and the Cranfield paradigm for the evaluation of information…

Presents a model information retrieval system for the case when a hierarchic set of descriptors is defined. (Author/PF)

These two indexing systems are briefly described and experimental evidence is cited showing that a combination of both theories produces better retrieval performance than either one alone. Appropriate conclusions are reached concerning viable automatic indexing procedures usable in practice. (Author)