Search (37 results, page 1 of 2)

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Content

Digital unter: http://dx.doi.org/10.1081/E-ELIS3-120043717. Vgl.: http://www.tandfonline.com/doi/book/10.1081/E-ELIS3.

Date

27. 8.2011 14:22:13

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Abstract

After a fundamental examination of the phenomenon of time, this paper presents the history, authority, and structure of period subdivisions and chronological terms in the three subject heading languages LCSH (Library of Congress Subject Headings), RAMEAU (Répertoire d'Autorité Matière Encyclopédique et Alphabétique Unifié), and RSWK (Regeln für den Schlagwortkatalog). Their usefulness in online searching is demonstrated using the online catalogs of the Library of Congress, the Bibliothèque nationale de France, and the Deutsche Bibliothek and is compared to the search options in selected digital encyclopedias (Encyclopaedia Britannica, Encarta, Brockhaus-Enzyklopädie). The author develops a model for common time retrieval across all three online catalogs, outlines the conditions for that model (time period code, chronological code, and chronology authority file), and proposes a search interface.

Date

10. 9.2000 17:38:22

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Abstract

Using subject headings for Online Retrieval is an indispensable tool for online system desingners who are developing new systems or refining exicting ones. The book describes subject analysis and subject searching in online catalogs, including the limitations of retrieval, and demonstrates how such limitations can be overcome through system design and programming. The book describes the Library of Congress Subject headings system and system characteristics, shows how information is stored in machine readable files, and offers examples of and recommendations for successful methods. Tables are included to support these recommendations, and diagrams, graphs, and bar charts are used to provide results of data analyses.

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Abstract

Information or Document Retrieval is the subject of this book. It is not an introductory book, although it is self-contained in the sense that it is not necessary to have a background in the theory or practice of Information Retrieval in order to understand its arguments. The book presents, as clearly as possible, one particular perspective on Information Retrieval, and attempts to say that certain aspects of the theory or practice of the management of documents are more important than others. The majority of Information Retrieval research has been aimed at the more experimentally tractable small-scale systems, and although much of that work has added greatly to our understanding of Information Retrieval it is becoming increasingly apparent that retrieval systems with large data bases of documents are a fundamentally different genre of systems than small-scale systems. If this is so, which is the thesis of this book, then we must now study large information retrieval systems with the same rigor and intensity that we once studied small-scale systems. Hegel observed that the quantitative growth of any system caused qualitative changes to take place in its structure and processes.

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Footnote

The guide Nuovo soggettario was presented on February 8' 2007 at a one-day seminar in the Palazzo Vecchio, Florence, in front of some 500 spellbound people. The Nuovo soggettario comes in two parts: the guide in book-form and an accompanying CD-ROM, by way of which a prototype of the thesaurus may be accessed on the Internet. In the former, rules are stated; the latter contains a pdf version of the guide and the first installment of the controlled vocabulary, which is to be further enriched and refined. Syntactic instructions (general application guidelines, as well as special annotations of particular terms) and the compiled subject strings file have yet to be added. The essentials of the new system are: 1) an analytic-synthetic approach, 2) use of terms (units of controlled vocabulary) and subject strings (which represent subjects by combining terms in linear order to form syntactic relationships), instead of main headings and subdivisions, 3) specificity of terms and strings, with a view to the co-extension of subject string and subject matter and 4) a clear distinction between semantic and syntactic relationships, with full control of them both. Basic features of the vocabulary include the uniformity and univocality of terms and thesaural management of a priori (semantic) relationships. Starting from its definition, each term can be categorially analyzed: four macro-categories are represented (agents, action, things, time), for which there are subcategories called facets (e.g., for actions: activities, disciplines, processes), which in turn have sub-facets. Morphological instructions conform to national and international standards, including BS 8723, ANSI/ NISO Z39.19 and the IFLA draft of Guidelines for multilingual thesauri, even for syntactic factorization. Different kinds of semantic relationships are represented thoroughly, and particular attention is paid to poly-hierarchies, which are used only in moderation: both top terms must actually be relevant. Node labels are used to specify the principle of division applied. Instance relationships are also used.
An entry is structured so as to present all the essential elements of the indexing system. For each term are given: category, facet, related terms, Dewey interdisciplinary class number and, if necessary; definition or scope notes. Sources used are referenced (an appendix in the book lists those used in the current work). Historical notes indicate whenever a change of term has occurred, thus smoothing the transition from the old lists. In chapter 5, the longest one, detailed instructions with practical examples show how to create entries and how to relate terms; upper relationships must always be complete, right up to the top term, whereas hierarchies of related terms not yet fully developed may remain unfinished. Subject string construction consists in a double operation: analysis and synthesis. The former is the analysis of logical functions performed by single concepts in the definition of the subject (e.g., transitive actions, object, agent, etc.) or in syntactic relationships (transitive relationships and belonging relationship), so that each term for those concepts is assigned its role (e.g., key concept, transitive element, agent, instrument, etc.) in the subject string, where the core is distinct from the complementary roles (e.g., place, time, form, etc.). Synthesis is based on a scheme of nuclear and complementary roles, and citation order follows agreed-upon principles of one-to-one relationships and logical dependence. There is no standard citation order based on facets, in a categorial logic, but a flexible one, although thorough. For example, it is possible for a time term (subdivision) to precede an action term, when the former is related to the latter as the object of action: "Arazzi - Sec. 16.-17. - Restauro" [Tapestry - 16th-17th century - Restoration] (p. 126). So, even with more complex subjects, it is possible to produce perfectly readable strings covering the whole of the subject matter without splitting it into two incomplete and complementary headings. To this end, some unusual connectives are adopted, giving the strings a more discursive style.
Now BNI is beginning to use the new language, pointing the way for the adoption of Nuovo soggettario in Italian libraries: a difficult challenge whose success is not assured. To name only one issue: including all fields of study requires particular care in treating terms with different specialized meanings; cooperation of other libraries and institutions is foreseen. At the same time, efforts are being made to assure the system's interoperability outside the library world. It is clear that a great commitment is required. "Too complex a system!" say the naysayers. "Only at the beginning," the proponents reply. The new system goes against the mainstream, compared with the imitation of the easy way offered by search engines - but we know that they must enrich their devices to improve quality, just repeating the work on semantic and syntactic relationships that leads formal expressions to the meanings they are intended to communicate - and also compared with research to create automated devices supporting human work, for the need to simplify cataloguing. Here AI is not involved, but automation is widely used to facilitate and to support the conscious work of indexers guided by rules as clear as possible. The advantage of Nuovo soggettario is its combination of a thesaurus (a much-appreciated tool used across the world) with the equally widespread technique of subject-string construction, which is to say: the rational and predictable combination of the terms used. The appearance of this original, unparalleled working model may well be a great occasion in the international development of indexing, as, on one hand, the Nuovo soggettario uses a recognized tool (the thesaurus) and, on the other, by permitting both pre-coordination and post-coordination, it attempts to overcome the fragmentation of increasingly complex and specialized subjects into isolated, single-term descriptors. This is a serious proposition that merits consideration from both theoretical and practical points of view - and outside Italy, too."

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Abstract

Despite early claims to the contemporary, thesauri continue to find use as access tools for information in the full-text environment. Their mode of use is changing, but this change actually represents an expansion rather than a contrdiction of their utility. Thesauri and similar vocabulary tools can complement full-text access by aiding users in focusing their searches, by supplementing the linguistic analysis of the text search engine, and even by serving as one of the tools used by the linguistic engine for its analysis. While human indexing contunues to be used for many databases, the trend is to increase the use of machine aids for this purpose. All machine-aided indexing (MAI) systems rely on thesauri as the basis for term selection. In the 21st century, the balance of effort between human and machine will change at both input and output, but thesauri will continue to play an important role for the foreseeable future

Date

22. 9.1997 19:16:05

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Abstract

Experimental evidence suggests that enhancing the subject content of OPAC records can improve retrieval performance. This is based on the use of natural language index terms derived from the table of contents and back-of-the-book index of documents. The research reported here investigates the alternative approach of translating these natural language terms into controlled vocabulary. Subject queries were collected by interview at the catalogue, and indexing of the queries demonstrated the impressive ability of PRECIS, and to a lesser extent LCSH, to represent users' information needs. DDC performed poorly in this respect. The assumption was made that an index language adequately specific to represent users' queries should be adequate to represent document contents. Searches were carried out on three test databases, and both natural language and PRECIS enhancement of MARC records increased the number of relevant documents found, with PRECIS showing the better performance. However, with weak stemming the advantage of PRECIS was lost. Consideration must also be given to the potential advantages of controlled vocabulary, over and above basic retrieval performance measures

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Abstract

In 1986 Libraries Unlimited published Cochrane's book, Improving LCSH for Use in Online Catalogs; Exercises for Self-Help with a Selection of Background Readings. This was preceded in 1981 by an ERIC publication (ED 208 900) by Cochrane, with Monika Kirtland Bibliographic and Bibliometric Essay which documented critical views of LCSH and an analysis of vocabulary control in LCSH (parts of which were published in Cataloging & Classification Quarterly' 1(2/3) (1982), 71-94). Three features of LCSH will be re-examined to check on progress since the time of these earlier publications: notes, structure of relationships between headings in the list, and links between Library of Congress classification numbers and LCSH or other vocabularies

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Abstract

The IFLA Section on Classification and Indexing's Working Group on Principles Underlying Subject Headings Languages has identified a set of eleven principles for subject heading languages and excerpted the texts that match each principle from the instructions for each of eleven national subject indexing systems, including excerpts from the LC's Subject Cataloging Manual: Subject Headings. This study compares the IFLA principles with other texts that express the principles underlying LCSH, especially Library of Congress Subject Headings: Principles of Structure and Policies for Application, prepared by Lois Mai Chan for the Library of Congress in 1990, Chan's later book on LCSH, and earlier documents by Haykin and Cutter. The principles are further elaborated for clarity and discussed

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Abstract

Describes the shortcomings of search engines for the WWW comparing their current capabilities to those of the first generation CD-ROM products. Some allow phrase searching and most are improving their Boolean searching. Few allow truncation, wild cards or nested logic. They are stateless, losing previous search criteria. Unlike the indexing and classification systems for today's CD-ROMs, those for Web pages are random, unstructured and of variable quality. Considers that at best Web search engines can only offer free text searching. Discusses whether automatic data classification systems such as Infoseek Ultra can overcome the haphazard nature of the Web with neural network technology, and whether Boolean search techniques may be redundant when replaced by technology such as the Euroferret search engine. However, artificial intelligence is rarely successful on huge, varied databases. Relevance ranking and automatic query expansion still use the same simple inverted indexes. Most Web search engines do nothing more than word counting. Further complications arise with foreign languages

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Abstract

Open system protocols for search and retrieval have not provided explicit ways in which to implement thesaurus-aided searching. A number of different approaches within the existing protocols, as well as a proposed service, are evaluated. A general approach to implementing thesaurus-aided searching, particularly during consultation of a thesaurus, requires an entirely new service, whose main features are described

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Abstract

In their 2005 study, Gross and Taylor found that more than a third of records retrieved by keyword searches would be lost without subject headings. A review of the literature since then shows that numerous studies, in various disciplines, have found that a quarter to a third of records returned in a keyword search would be lost without controlled vocabulary. Other writers, though, have continued to suggest that controlled vocabulary be discontinued. Addressing criticisms of the Gross/Taylor study, this study replicates the search process in the same online catalog, but after the addition of automated enriched metadata such as tables of contents and summaries. The proportion of results that would be lost remains high.

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Abstract

When consumers search for health information, a major obstacle is their unfamiliarity with the medical terminology. Even though medical thesauri such as the Medical Subject Headings (MeSH) and related tools (e.g., the MeSH Browser) were created to help consumers find medical term definitions, the lack of direct and explicit integration of these help tools into a health retrieval system prevented them from effectively achieving their objectives. To explore this issue, we conducted an empirical study with two systems: One is a simple interface system supporting query-based searching; the other is an augmented system with two new components supporting MeSH term searching and MeSH tree browsing. A total of 45 subjects were recruited to participate in the study. The results indicated that the augmented system is more effective than the simple system in terms of improving user-perceived topic familiarity and question-answer performance, even though we did not find users spend more time on the augmented system. The two new MeSH help components played a critical role in participants' health information retrieval and were found to allow them to develop new search strategies. The findings of the study enhanced our understanding of consumers' search behaviors and shed light on the design of future health information retrieval systems.

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Abstract

Subject searching is difficult with traditional text-based online public access library catalogues (OPACs), and the next-generation discovery layers are keyword searching and result filtering tools that offer little support for subject browsing. Next-generation OPACs ignore the rich network of relations offered by controlled subject vocabulary, which can facilitate subject browsing. A new generation of OPACs could leverage existing information-organization investments and offer online searchers a novel browsing and searching environment. This is a case study of the design and development of a virtual reality subject browsing and information retrieval tool. The functional prototype shows that the Library of Congress subject headings (LCSH) can be shaped into a useful and usable tree structure serving as a visual metaphor that contains a real world collection from the domain of science and engineering. Formative tests show that users can effectively browse the LCSH tree and carve it up based on their keyword search queries. This study uses a complex information-organization structure as a defining characteristic of an OPAC that goes beyond the standard keyword search model, toward the cutting edge of online search tools.

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Abstract

Investigates the extent to which title keywords convey subject content and compares the relative effectiveness of searching title keywords using 2 search strategies to examine whether adjacency operators in title keyword searches are effective in improving recall and precision of online searching. Title keywords from a random sample of titles in the field of economics were searched on FirstSearch, using the WorldCat database, which is equivalent in coverage to the OCLC OLUC, with and without adjacency of the keywords specified. The LCSH of the items retrieved were compared with the sample title subject headings to determine the degree of match or relevance and the values for precision and recall were calculated. Results indicated that, when keywords were discipline specific, adjacency operators improved precision with little degradation of recall. Systems that allow positional operators or rank output by proximity of terms may increase search success

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Source

Searcher. 3(1995) no.8, S.18-22

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Abstract

In online retrieval search results do not always match the intent in spite of using correct keywords (descriptors). One of the causes of this problem is found in the hierarchical structures of the thesaurus, which often contains relations between broader and narrower concepts, the opposite of which is not necessarily true. Some examples are described from 2 thesauri, MeSH and JICST. In these cases searchers need to make an effort to increase precision

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Abstract

Purpose - This paper attempts to explain the wide dissemination of Library of Congress Subject Headings (LCSH) within digital libraries and presents some of the advantages and disadvantages of using this controlled vocabulary in digital collections. The paper also presents other classifications used in digital collections for subject access and explores ways of improving search functionality in digital collections that employ LCSH. Design/methodology/approach - Unlike traditional libraries that use Library of Congress Classification for organization and retrieval, digital libraries use metadata forms for organization and retrieval. The collections exist in cyberspace of the internet which is known for containing the universe of knowledge. The use of LCSH for information retrieval has been widely criticized for its difficulty of use and its information retrieval effectiveness in online environments. The Library of Congress (LOC) has claimed the headings were not based on comprehensive principles nor ever intended to cover the universe of knowledge. Despite these claims and criticisms, LCSH is the most popular choice for subject access in digital libraries. Findings - The number of digital collections increases every year and LCSH is still the most popular choice of controlled vocabulary for subject access. Of the numerous criticisms, difficulties of use and user unfamiliarity are the greatest disadvantages of using LCSH for subject access. Average users only have a vague notion of what they are looking for when initializing a search. More work is required in automated generation of subject headings and increased usage of LCSH in faceted search retrieval systems. This will provide users with better access to the LCSH used in the back end of information retrieval. Originality/value - The Greek researchers who developed the Dissertation DSPace system believe this type of module will eventually replace the traditional keyword-based indexing back ends employed by many information retrieval modules within current digital library systems. The system offers the type of access and interactivity that will acquaint users with how LCSH looks and is used. Faceted search and automated pattern matching using an ontology based on LCSH have the best promise of overcoming the disadvantages that have always plagued the LOC-controlled vocabulary. These retrieval techniques give LCSH an opportunity to finally achieve the optimal precision and recall it has so far failed to deliver.