Search (33 results, page 1 of 2)

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Abstract

Describes an experiment comparing the performance of automatic full-text indexing software for personal computers with the human intellectual assignment of indexing terms in each document in a collection. Considers the times required to index the document, to retrieve documents satisfying 5 typical foreseen information needs, and the recall and precision ratios of searching. The software used is QuickFinder facility in WordPerfect 6.1 for Windows

Source

Canadian journal of information and library science. 21(1996) no.2, S.1-22

Type

a

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Abstract

A known-item search for abstracts to previously retrieved references revealed that 2 documents from the same annual volume had been indexed twice. Working from the premise that the whole volume may have been double-indexed, a search strategy was devised that limited the journal code to the year in question. 57 references were retrieved, comprising 28 pairs of duplicates plus a citation for the whole volume. Author, title, source and descriptors were requested off-line and the citations were paired with their duplicates. The 4 categories of descriptors-major descriptors, minor descriptors, subheadings and check-tags-were compared for depth and consistency of indexing and lessons that might be learnt from the study are discussed.

Source

Health libraries review. 7(1990) no.1, S.22-26

Type

a

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Abstract

An important stage in the process or retrieval of objects from a hypertext database is the creation of a set of internodal links that are intended to represent the relationships existing between objects; this operation is often undertaken manually, just as index terms are often manually assigned to documents in a conventional retrieval system. In an earlier article (1994), the results were published of a study in which several different sets of links were inserted, each by a different person, between the paragraphs of each of a number of full-text documents. These results showed little similarity between the link-sets, a finding that was comparable with those of studies of inter-indexer consistency, which suggest that there is generally only a low level of agreement between the sets of index terms assigned to a document by different indexers. In this article, a description is provided of an investigation into the nature of the relationship existing between (i) the levels of inter-linker consistency obtaining among the group of hypertext databases used in our earlier experiments, and (ii) the levels of effectiveness of a number of searches carried out in those databases. An account is given of the implementation of the searches and of the methods used in the calculation of numerical values expressing their effectiveness. Analysis of the results of a comparison between recorded levels of consistency and those of effectiveness does not allow us to draw conclusions about the consistency - effectiveness relationship that are equivalent to those drawn in comparable studies of inter-indexer consistency

Type

a

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Abstract

Reports results of a study of 2 information retrieval systems on a 2.000 document full text medical database. The first system, SAPHIRE, features concept based automatic indexing and statistical retrieval techniques, while the second system, SWORD, features traditional word based Boolean techniques, 16 medical students at Oregon Health Sciences Univ. each performed 10 searches and their results, recorded in terms of recall and precision, showed nearly equal performance for both systems. SAPHIRE was also compared with a version of SWORD modified to use automatic indexing and ranked retrieval. Using batch input of queries, the latter method performed slightly better

Type

a

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Abstract

Recent papers have called attention to discrepancies in the assignment of LCSH. While philosophical arguments can be made that subject analysis, if not a logical impossibility, at least is point-of-view dependent, subject headings continue to be assigned and continue to be useful. The hypothesis advanced in the present project is that to a considerable degree there is a clear-cut right and wrong to LCSH subject heading assignment. To test the hypothesis, it was postulated that the assignment of a subject heading is correct if it is supported by textual warrant (at least 20% of the book being cataloged is on the topic) and is constructed in accordance with the LoC Subject Cataloging Manual: Subject Headings. A sample of 100 books on scientific subjects was used to test the hypothesis

Type

a

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Abstract

This article introduces a new concept and technique for information retrieval called 'colinked descriptors'. Borrowed from an analogous idea in bibliometrics - cocited references - colinked descriptors provide a theory and method for identifying search terms that, by hypothesis, will be superior to those entered initially by a searcher. The theory suggests a means of moving automatically from 2 or more initial search terms, to other terms that should be superior in retrieval performance to the 2 original terms. A research project designed to test this colinked descriptor hypothesis is reported. The results suggest that the approach is effective, although methodological problems in testing the idea are reported. Algorithms to generate colinked descriptors can be incorporated easily into system interfaces, front-end or pre-search systems, or help software, in any database that employs a thesaurus. The potential use of colinked descriptors is a strong argument for building richer and more complex thesauri that reflect as many legitimate links among descriptors as possible

Type

a

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Abstract

A total of 16 classifiers made a subject analysis of a set of books such that some of the books were first classified by the UDC anf then indexed with terms from the General Finnish Subject Headings while another set were processed in the opposite order. Finally books on the same subject were either classifies or indexed. The total number of books processed was 581. A comparison was made of the time required for processing in different situations and of the number of classes or subject headings used. The time figures were compared with corresponding data from the British Library (1972) and the Library of Congress (1990 and 1991). The author finds that the contents analysis requires one third, classification one third and indexing obe third of the time, if the document is both classified and indexed. There was a plausible correlation (o.51) between the length of experience in classification and the decrease in the time required for classing. The average number of UDC numbers was 4,3 and the average number of terms from the list of subject headings was 4,0

Type

a

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Abstract

Indexers differ in their judgement as to which terms reflect adequately the content of a document. Studies of interindexers' consistency identified several factors associated with low consistency, but failed to provide a comprehensive model of this phenomenon. Our research applies theories and methods from cognitive psychology to the study of indexing behavior. From a theoretical standpoint, indexing is considered as a problem solving situation. To access to the cognitive processes of indexers, 3 kinds of verbal reports are used. We will present results of an experiment in which 4 experienced indexers indexed the same documents. It will be shown that the 3 kinds of verbal reports provide complementary data on strategic behavior, and that it is of prime importance to consider the indexing task as an ill-defined problem, where the solution is partly defined by the indexer him(her)self

Source

Connectedness: information, systems, people, organizations. Proceedings of CAIS/ACSI 95, the proceedings of the 23rd Annual Conference of the Canadian Association for Information Science. Ed. by Hope A. Olson and Denis B. Ward

Type

a

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Abstract

Reports 3 explorations of ranked system design. 2 tests used a 'cystic fibrosis' test collection with 100 queries. Experiment 1 compared a Boolean with a ranked interactive system using a subject qualified trained searcher, and reporting recall and precision results. Experiment 2 compared 15 different ranked match algorithms in a batch mode using 2 test collections, and included some new proximate pairs and term weighting approaches. Experiment 3 is a design plan for an interactive ranked prototype offering mid search algorithm choices plus other manual search devices (such as obligatory and unwanted terms), as influenced by thinking aloud comments from experiment 1. Concludes that, in Boolean versus ranked using inverse collection frequency, the searcher inspected more records on ranked than Boolean and so achieved a higher recall but lower precision; however, the presentation order of the relevant records, was, on average, very similar in both systems. Concludes also that: query reformulation was quite strongly practised in ranked searching but does not appear to have been effective; the term pairs proximate weithing methods in experiment 2 enhanced precision on both test collections when used with inverse collection frequency weighting (ICF); and the design plan for an interactive prototype adds to a selection of match algorithms other devices, such as obligatory and unwanted term marking, evidence for this being found from think aloud comments

Type

a

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Abstract

The study was based on the collection examnined by W.H. Shaw (Inf. proc. man. 26(1990) no.6, S.693-703, 705-718), a test collection of 1239 articles, indexed with the term cystic fibrosis; and 100 queries with 3 sets of relevance evaluations from subject experts. The effect of variations in indexing exhaustivity on retrieval performance in a vector space retrieval system was investigated by using a term weight threshold to construct different document representations for a test collection. Retrieval results showed that retrieval performance, as measured by the mean optimal measure for all queries at a term weight threshold, was highest at the most exhaustive representation, and decreased slightly as terms were eliminated and the indexing representation became less exhaustive. The findings suggest that the vector space model is more robust against variations in indexing exhaustivity that is the single-link clustering model

Type

a

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Abstract

This study measures inter-indexer consistency as determined by the number of identical terms assigned to the same document by two different indexing organizations using the same thesaurus as a source for the entry vocabulary. The authors derive consistency figures of 24 percent and 45 percent for two samples. Factors in the consistency failures include variations in indexing depth, differences in choice of concepts for indexing, different indexing policies, and a highly specific indexing vocabulray. Results indicate that broad search strategies are often necessary for adequate search yields.

Type

a

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Abstract

Indexing consistency between Library of Congress and British Library catalogers using the LCSH is compared.82 titles published in 1987 in the field of library and information science were identified for comparison, and for each title its LC subject headings, assigned by both LC and BL catalogers, were compared. By applying Hooper's 'consistency of a pair' equation, the average indexing consistency value was calculated for the 82 titles. The average indexing value between LC and BL catalogers is 16% for exact matches, and 36% for partial matches

Type

a

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Source

From classification to 'knowledge organization': Dorking revisited or 'past is prelude'. A collection of reprints to commemorate the firty year span between the Dorking Conference (First International Study Conference on Classification Research 1957) and the Sixth International Study Conference on Classification Research (London 1997). Ed.: A. Gilchrist

Type

a

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Abstract

This article revisits the debate concerning controlled and natural indexing languages, as used in searching the databases of the online hosts, in-house information retrieval systems, online public access catalogues and databases stored on CD-ROM. The debate was first formulated in the early days of information retrieval more than a century ago but, despite significant advance in technology, remains unresolved. The article divides the history of the debate into four eras. Era one was characterised by the introduction of controlled vocabulary. Era two focused on comparisons between different indexing languages in order to assess which was best. Era three saw a number of case studies of limited generalisability and a general recognition that the best search performance can be achieved by the parallel use of the two types of indexing languages. The emphasis in Era four has been on the development of end-user-based systems, including online public access catalogues and databases on CD-ROM. Recent developments in the use of expert systems techniques to support the representation of meaning may lead to systems which offer significant support to the user in end-user searching. In the meantime, however, information retrieval in practice involves a mixture of natural and controlled indexing languages used to search a wide variety of different kinds of databases

Type

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Abstract

The development of regional on-line catalogs and in-house information systems for retrieval of references provide examples of the impact of indexing theory and applications on technical processing. More emphasis must be given to understanding the techniques for evaluating the effectiveness of a file, irrespective of whether that file was created as a library catalog or an index to information sources. The most significant advances in classification theory in recent decades has been as a result of efforts to improve effectiveness of indexing systems. Library classification systems are indexing languages or systems. Courses offered for the preparation of indexers in the United States and the United Kingdom are reviewed. A point of congruence for both the indexer and the library classifier would appear to be the need for a thorough preparation in the techniques of subject analysis. Any subject heading list will suffer from omissions as well as the inclusion of terms which the patron will never use. Indexing theory has provided the technical services department with methods for evaluation of effectiveness. The writer does not believe that these techniques are used, nor do current courses, workshops, and continuing education programs stress them. When theory is totally subjugated to practice, critical thinking and maximum effectiveness will suffer.

Type

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Abstract

The LCC and DDC systems were devised and updated by librarians who had and have no access to the eventual frequency of use of each number in those classification systems. 80% of the monographs in a MARC file of over 1.000.000 records are classified into 20% of the classification numbers in the field of library science and only 20% of the mongraphs are classified into 80% of the classification numbers in the field of library science. Classification of monographs coulld be made easier and performed more accurately if many of the little used and unused numbers were eliminated and many of the most crowded numbers were expanded. A number of examples are included

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Abstract

Reports on an analysis of lexical ambiguity in information retrieval text collections and on experiments to determine the utility of word meanings for separating relevant from nonrelevant documents. Results show that there is considerable ambiguity even in a specialised database. Word senses provide a significant separation between relevant and nonrelevant documents, but several factors contribute to determining whether disambiguation will make an improvement in performance such as: resolving lexical ambiguity was found to have little impact on retrieval effectiveness for documents that have many words in common with the query. Discusses other uses of word sense disambiguation in an information retrieval context

Type

a

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Abstract

Automatic keyword extraction is an important and fundamental technology in an advanced information retrieval systems. Briefly compares several major keyword extraction methods, lists their advantages and disadvantages, and reports recent research progress in Taiwan. Also describes the application of a keyword extraction algorithm in an information retrieval system for relevance feedback. Preliminary analysis shows that the error rate of extracting relevant keywords is 18%, and that the precision rate is over 50%. The main disadvantage of this approach is that the extraction results depend on the retrieval results, which in turn depend on the data held by the database. Apart from collecting more data, this problem can be alleviated by the application of a thesaurus constructed by the same keyword extraction algorithm

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Abstract

This article presents the results of research into the automatic selection of Library of Congress Classification numbers based on the titles and subject headings in MARC records. The method used in this study was based on partial match retrieval techniques using various elements of new recors (i.e., those to be classified) as "queries", and a test database of classification clusters generated from previously classified MARC records. Sixty individual methods for automatic classification were tested on a set of 283 new records, using all combinations of four different partial match methods, five query types, and three representations of search terms. The results indicate that if the best method for a particular case can be determined, then up to 86% of the new records may be correctly classified. The single method with the best accuracy was able to select the correct classification for about 46% of the new records.

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a

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Type

a