Search (8 results, page 1 of 1)

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Theme

Konzeption und Anwendung des Prinzips Thesaurus

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Abstract

A thesaurus may be viewed as a graph, and document retrieval algorithms can exploit this graph when both the documents and the query are represented by thesaurus terms. These retrieval algorithms measure the distance between the query and documents by using the path lengths in the graph. Previous work witj such strategies has shown that the hierarchical relations in the thesaurus are useful but the non-hierarchical are not. This paper shows that when the query explicitly mentions a particular non-hierarchical relation, the retrieval algorithm benefits from the presence of such relations in the thesaurus. Our algorithms were applied to the Excerpta Medica bibliographic citation database whose citations are indexed with terms from the EMTREE thesaurus. We also created an enriched EMTREE by systematically adding non-hierarchical relations from a medical knowledge base. Our algorithms used at one time EMTREE and, at another time, the enriched EMTREE in the course of ranking documents from Excerpta Medica against queries. When, and only when, the query specifically mentioned a particular non-hierarchical relation type, did EMTREE enriched with that relation type lead to a ranking that better corresponded to an expert's ranking

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Abstract

Connecting and evaluating thesauri is an important task for the systematic development of better information retrieval systems. Connecting thesauri includes not only determining when terms in different thesauri are the same but also determining what kinds of relationships can be transferred from one thesaurus to another. This paper first presents issues in connecting and evaluating thesauri. Various experiments in connecting a particular thesaurus, the Medical Subject Headings, with other medical thesauri are described. In these experiments, similar terms in two thesauri are recognized and then differences in two thesauri are exploited to create more powerful thesauri. Part of the evaluation requires the thesaurus to support automatic indexing and retrieving of documents

Theme

Konzeption und Anwendung des Prinzips Thesaurus

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Abstract

Maintaining a thesaurus is a time-consuming task which should go hand-in-hand with the indexing of information and should be supported by software. To connect different document databases their respective thesauri should be related. The most straightforward way to support to support this by computer is to map the terms of one thesaurus to those of another. Such a mapping creates one kind of metathesaurus. As citation systems are extended to include full-text online, a new thesaurus may be used to index individual paragraphs. To illustrate these principles several computer systems are described which help people maintain thesauri and metathesauri. Particular success has been had by the National Library of Medicine with its Medical Subject Headings and its Unified Medical Language System

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Abstract

Online textbooks can be connected to other sources of information to improve their educational value. We describe 2 case studies. One used in a medical textbook and connected to medical journal abstracts via a thesaurus. The textbook, journal abstracts, and thesaurus were stored on a CD-ROM. The other case study shows a textbook on the WWW that is connected to various other sources of information. About half the book references are to web sites, and the textbook is part of an online course that is connected to an online catalog and other courses. Such linkages among information spaces should help students navigate the information relevant to their studies

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Source

International journal of information management. 11(1991) no.1, S.14-22