Compares two information retrieval systems, CLARIT and TOPIC, in terms of assigned versus derived and precoordinate versus postcoordinate indexing. Models of information retrieval systems are discussed, and a test of the systems using a demonstration database of full-text articles from the "Wall Street Journal" is described. (Contains 21…

An analysis of the question of the optimal depth of indexing in order to design an effective document retrieval system is presented. It is shown that some more fundamental questions about indexing and retrieval rather than indexing depth are central to the issue. (Author/MBR)

Suggests a probabilistic method to compute the term relationships from relevance information, which complements the studies on a nonprobabilistic technique called pseudo-classification. A quadratic ranking function is derived by incorporating the term-by-term relationships. Procedures for estimating the required parameters are provided by…

A model which relates the access control and indexing functions. The model is based on concept protection which allows a practically unbounded number of levels (subsets) of protection without requiring a fixed hierarchy among the levels. This protection is offered independently for each of the user operations allowed. (Author)

Discussion of the failure of individual keywords to identify conceptual content of documents in retrieval systems highlights Metric Similarity Modeling, a method for creating vector space representation of documents based on modeling target interdocument similarity values. Semantic relatedness, latent semantic indexing, an indexing and retrieval…

Demonstrates the use of a directed graph model as a tool for finding desirable minimum vocabularies to be used in indexing and information retrieval. The basic algorithm is outlined, possible enhancements to the model are discussed, and further research questions are suggested. (Author/CLB)

The retrieval effectiveness of Keywork-In-Context (KWIC) indexing is sought using a simple search simulation which constrains the user to approach a KWIC index with subject keywords and references dictated by a conventional index. A comparison of several KWIC index studies, using various methodologies, shows retrievability ratios of 35 percent -…

Discussion of models for indexing and searching information resources on the Internet focuses on the results of a simple query on a number of existing search systems and on two proposed index metadata structures for indexing and supporting search and discovery: the Dublin Core Elements List and the Semantic Header. (52 references) (Author/LRW)

Proposes split model for index term distribution in document set that uses rank function for high frequency terms and size function for low frequency terms; the point of transition is determined either empirically or by rule. Distributions to describe index term exhaustivity and term co-occurrence are considered briefly. (36 references) (EJS)

Proposes an automated document classification system based on the Gray code, information-theoretic considerations, and requirements of classification systems including objectivity, inclusion, linearity, and increasing distance-dissimilarity. A measure to evaluate system performance is developed, and the proposed system is compared with the Library…

Presents a texture-based image-retrieval system for browsing large-scale aerial photographs. System components include texture-feature extraction, image segmentation and grouping, learning-similarity measure, and a texture-thesaurus model for fast search and indexing. Testing has demonstrated the system's effectiveness in searching and selecting…

Describes the development of an information retrieval system designed for nonspecialist users that is based on the binary vector model. The syntactic structure of phrases used for indexing is examined, queries using an experimental collection of documents are described, and precision values are examined. (19 references) (LRW)

Examines some nonbook materials with respect to an aboutness model of indexing, showing that there are instances that defy subject indexing. These occur not so much because of the nature of the medium but because it is being used for nondocumentary purposes or because the subject referenced is nonlexical. (Contains 20 references.) (KRN)

Proposes a model of the search term selection process based on an empirical study of professional searchers during the pre-online search stage; the model characterizes the selection of search terms as the navigation of different discourses. Six discourses emerged as sources of search terms: controlled vocabularies; documents and the domain; the…

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.…