Compares the differences in coverage and utility of three substructure databases--Chemical Abstracts, Index Chemicus, and Chemical Information System's Nomenclature Search System. The differences between Chemical Abstracts with two different vendors--STN International and Questel--are described and a summary guide for choosing between databases is…

Presents a general mathematical framework for information retrieval, in which query evaluation is seen as a mapping from the free term algebra built by query descriptors and weights to the semantic algebra of evaluation value. Competing mathematical models that try to describe how retrieval systems behave are reviewed. (Author/MBR)

Conceptualizes five different types of information seeking expressions identified by an analysis of a sample of such expressions (i.e., questions, requests, statements, commands, and truncated expressions) and discusses the implications of the resulting distinctions for practices in information retrieval. Two recommendations are offered to improve…

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 -…

The performance of a selective dissemination of information service based on computer scanning of Nuclear Science Abstracts tapes was compared with a current awareness service based on visual scanning of journals and reports by information specialists. (6 references) (Author/SJ)

A retrospective test search on one year of CA Condensates was carried out in order to calculate the costs per profile and to get an impression of how CA Condensates would suffice as a database for retrospective use. (11 references) (Author)

The substitution information contained in automatically obtained keyword classification is most effectively exploited when: (1) strong similarity connectives only are utilized, (2) grouping is confined to non-frequent terms, (3) term groups are used to provide additional and not alternative descriptive items and (4) descriptor collection frequency…

Design equations are derived for three types of retrieval systems. The equation in each case shows the relationship between expected search length, used as a performance measure, and certain system characteristics having to do with the distribution of index terms over the document collection and the number of errors in the search requests. (MF)

This paper deals with quantitative evaluation of the effects of erroneous performance by stemming and similar clustering algorithms in information retrieval systems. (Author)

Discussion of the process of library cataloging notes the 8th century cataloger, Alcuin; purpose of cataloging; bibliographic control; access to information; cataloging on OCLC; emphasis on the format in which cataloging information is communicated; lost precision; authority files; and recall versus precision. Seven references are included. (EJS)

An information retrieval system which aspires to retrieval of relevant documents should have second stage which will order topical set to provide maximum informativeness to requestor. A two-stage system concerned only with topicality can be iterated to generate a high recall set and discard imprecise documents without user input. (EJS)

Reviews the advantages and disadvantages of different types of term combination using the positional logic capability of online information retrieval systems and describes a study in which searches for material on "microwave integrated circuits" were conducted in order to find the most economical way of generating the most relevant…

Demonstrates that if simple foundations of the cost structure are taken into consideration, high values of both precision and recall are not necessarily the goal when searching in an information system. Five figures and a reference list accompany the text. (Author/JL)

Discusses the problem of how to permit a patron to represent the relative importance of various index terms in a Boolean request while retaining the desirable properties of a Boolean system. (FM)