Search (81 results, page 1 of 5)

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Date

8.12.2007 19:25:22

Source

Information - Wissenschaft und Praxis. 58(2007) H.8, S.441-444

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a

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Date

24. 8.2005 19:20:22

Type

a

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Abstract

A discussion on current initiatives regarding terminology registries.

Date

26.12.2011 13:22:07

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Abstract

A thesaurus in the controlled vocabulary environment is a tool designed to support effective infonnation retrieval (IR) by guiding indexers and searchers consistently to choose the same terms for expressing a given concept or combination of concepts. Terms in the thesaurus are linked by relationships of three well-known types: equivalence, hierarchical, and associative. The functions and properties of these three basic types and some subcategories are described, as well as some additional relationship types conunonly found in thesauri. Progressive automation of IR processes and the capability for simultaneous searching of vast networked resources are creating some pressures for change in the categorization and consistency of relationships.

Date

22. 9.2007 15:45:57

Type

a

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Abstract

The present study investigates the ability of a bibliometric based semi-automatic method to select candidate thesaurus terms from citation contexts. The method consists of document co-citation analysis, citation context analysis, and noun phrase parsing. The investigation is carried out within the specialty area of periodontology. The results clearly demonstrate that the method is able to select important candidate thesaurus terms within the chosen specialty area.

Date

8. 3.2007 19:55:22

Type

a

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Abstract

The purpose of this selected bibliography is to introduce issues and problems in relation to thesaurus construction and to present a set of readings that may be used in practical thesaurus design. The concept of thesaurus is discussed, the purpose of the thesaurus and how the concept has evolved over the years according to new IR technologies. Different approaches to thesaurus construction are introduced, and readings dealing with specific problems and developments in the collection, formation and organisation of thesaurus concepts and terms are presented. Primarily manual construction methods are discussed, but the bibliography also refers to research about techniques for automatic thesaurus construction.

Date

18. 5.2006 20:06:22

Type

a

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Abstract

After a period of experiment and evolution in the 1950s and 1960s, a fairly standard format for thesauri was established with the publication of the influential Thesaurus of Engineering and Scientific Terms (TEST) in 1967. This and other early thesauri relied primarily an the presentation of terms in alphabetical order. The value of a classified presentation was subsequently realised, and in particular the technique of facet analysis has profoundly influenced thesaurus evolution. Thesaurofacet and the Art & Architecture Thesaurus have acted as models for two distinct breeds of thesaurus using faceted displays of terms. As of the 1990s, the expansion of end-user access to vast networked resources is imposing further requirements an the style and structure of controlled vocabularies. The international standards for thesauri, first conceived in a print-based era, are badly in need of updating. Work is in hand in the UK and the USA to revise and develop standards in support of electronic thesauri.

Date

22. 9.2007 15:46:13

Type

a

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Abstract

The need for Persian thesauri became apparent during the late 1960s with the advent of documentation centres in Iran. The first Persian controlled vocabulary was published by IRANDOC in 1977. Other centres worked on translations of existing thesauri, but it was soon realised that these efforts did not meet the needs of the centres. After the Islamic revolution in 1979, the foundation of new centres intensified the need for Persian thesauri, especially in the fields of history and government documents. Also, during the Iran-Iraq war, Iranian research centres produced reports in scientific and technical fields, both to support military requirements and to meet society's needs. In order to provide a comprehensive thesaurus, the Council of Scientific Research of Iran approved a project for the compilation of such a work. Nowadays, 12 Persian thesauri are available and others are being prepared, based on the literary corpus and conformity with characteristics of Iranian culture.

Source

Indexer. 25(2006) no.1, S.19-22

Type

a

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Abstract

In this demonstration we present a visual analysis approach that addresses both developers and users of hierarchical classification systems. The approach supports an intuitive understanding of the structure and current use in relation to a specific collection. We will also demonstrate its application for the development and management of library collections.

Type

a

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Abstract

Statistical methods for automated document indexing are becoming an alternative to the manual assignment of keywords. We argue that the quality of the thesaurus used as a basis for indexing in regard to its ability to adequately cover the contents to be indexed and as a basis for the specific indexing method used is of crucial importance in automatic indexing. We present an interactive tool for thesaurus evaluation that is based on a combination of statistical measures and appropriate visualisation techniques that supports the detection of potential problems in a thesaurus. We describe the methods used and show that the tool supports the detection and correction of errors, leading to a better indexing result.

Type

a

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Abstract

This paper evaluates and compares three thesaurus construction methodologies: literary scanning, word association tests, and involvement of subject expert groups. The evaluation concentrates an exploring advantages in relation to the sub-processes: collection, formation and structuring of concepts and terms. Quantitative as well as qualitative analyses have been carried out. The analysis Shows that the methods are complementary each providing distinct conceptual information from respectively a domain-oriented and a scientific viewpoint. The combination of methods provides a thesaurus, at the same time, mapping authoritative language and reflecting the diversity of language.

Type

a

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Abstract

Tseng constructs a word co-occurrence based thesaurus by means of the automatic analysis of Chinese text. Words are identified by a longest dictionary match supplemented by a key word extraction algorithm that merges back nearby tokens and accepts shorter strings of characters if they occur more often than the longest string. Single character auxiliary words are a major source of error but this can be greatly reduced with the use of a 70-character 2680 word stop list. Extracted terms with their associate document weights are sorted by decreasing frequency and the top of this list is associated using a Dice coefficient modified to account for longer documents on the weights of term pairs. Co-occurrence is not in the document as a whole but in paragraph or sentence size sections in order to reduce computation time. A window of 29 characters or 11 words was found to be sufficient. A thesaurus was produced from 25,230 Chinese news articles and judges asked to review the top 50 terms associated with each of 30 single word query terms. They determined 69% to be relevant.

Type

a

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Abstract

This paper discusses issues concerning the augmentation of thesaurus relationships, in light of new application possibilities for retrieval. We first discuss a case study that explored the retrieval potential of an augmented set of thesaurus relationships by specialising standard relationships into richer subtypes, in particular hierarchical geographical containment and the associative relationship. We then locate this work in a broader context by reviewing various attempts to build taxonomies of thesaurus relationships, and conclude by discussing the feasibility of hierarchically augmenting the core set of thesaurus relationships, particularly the associative relationship. We discuss the possibility of enriching the specification and semantics of Related Term (RT relationships), while maintaining compatibility with traditional thesauri via a limited hierarchical extension of the associative (and hierarchical) relationships. This would be facilitated by distinguishing the type of term from the (sub)type of relationship and explicitly specifying semantic categories for terms following a faceted approach. We first illustrate how hierarchical spatial relationships can be used to provide more flexible retrieval for queries incorporating place names in applications employing online gazetteers and geographical thesauri. We then employ a set of experimental scenarios to investigate key issues affecting use of the associative (RT) thesaurus relationships in semantic distance measures. Previous work has noted the potential of RTs in thesaurus search aids but also the problem of uncontrolled expansion of query term sets. Results presented in this paper suggest the potential for taking account of the hierarchical context of an RT link and specialisations of the RT relationship

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Abstract

Many information professionals working in small units today fail to find the published tools for subject-based organization that are appropriate to their local needs, whether they are archivists, special librarians, information officers, or knowledge or content managers. Large established standards for document description and organization are too unwieldy, unnecessarily detailed, or too expensive to install and maintain. In other cases the available systems are insufficient for a specialist environment, or don't bring things together in a helpful way. A purpose built, in-house system would seem to be the answer, but too often the skills necessary to create one are lacking. This practical text examines the criteria relevant to the selection of a subject-management system, describes the characteristics of some common types of subject tool, and takes the novice step by step through the process of creating a system for a specialist environment. The methodology employed is a standard technique for the building of a thesaurus that incidentally creates a compatible classification or taxonomy, both of which may be used in a variety of ways for document or information management. Key areas covered are: What is a thesaurus? Tools for subject access and retrieval; what a thesaurus is used for? Why use a thesaurus? Examples of thesauri; the structure of a thesaurus; thesaural relationships; practical thesaurus construction; the vocabulary of the thesaurus; building the systematic structure; conversion to alphabetic format; forms of entry in the thesaurus; maintaining the thesaurus; thesaurus software; and; the wider environment. Essential for the practising information professional, this guide is also valuable for students of library and information science.

Footnote

Rez. in: Mitt. VÖB 60(2007) H.1, S.98-101 (O. Oberhauser): "Die Autorin von Essential thesaurus construction (and essential taxonomy construction, so der implizite Untertitel, vgl. S. 1) ist durch ihre Lehrtätigkeit an der bekannten School of Library, Archive and Information Studies des University College London und durch ihre bisherigen Publikationen auf den Gebieten (Facetten-)Klassifikation und Thesaurus fachlich einschlägig ausgewiesen. Nach Essential classification liegt nun ihr Thesaurus-Lehrbuch vor, mit rund 200 Seiten Text und knapp 100 Seiten Anhang ein handliches Werk, das seine Genese zum Grossteil dem Lehrbetrieb verdankt, wie auch dem kurzen Einleitungskapitel zu entnehmen ist. Das Buch ist der Schule von Jean Aitchison et al. verpflichtet und wendet sich an "the indexer" im weitesten Sinn, d.h. an alle Personen, die ein strukturiertes, kontrolliertes Fachvokabular für die Zwecke der sachlichen Erschliessung und Suche erstellen wollen bzw. müssen. Es möchte dieser Zielgruppe das nötige methodische Rüstzeug für eine solche Aufgabe vermitteln, was einschliesslich der Einleitung und der Schlussbemerkungen in zwanzig Kapiteln geschieht - eine ansprechende Strukturierung, die ein wohldosiertes Durcharbeiten möglich macht. Zu letzterem tragen auch die von der Autorin immer wieder gestellten Übungsaufgaben bei (Lösungen jeweils am Kapitelende). Zu Beginn der Darstellung wird der "information retrieval thesaurus" von dem (zumindest im angelsächsischen Raum) weit öfter mit dem Thesaurusbegriff assoziierten "reference thesaurus" abgegrenzt, einem nach begrifflicher Ähnlichkeit angeordneten Synonymenwörterbuch, das gerne als Mittel zur stilistischen Verbesserung beim Abfassen von (wissenschaftlichen) Arbeiten verwendet wird. Ohne noch ins Detail zu gehen, werden optische Erscheinungsform und Anwendungsgebiete von Thesauren vorgestellt, der Thesaurus als postkoordinierte Indexierungssprache erläutert und seine Nähe zu facettierten Klassifikationssystemen erwähnt. In der Folge stellt Broughton die systematisch organisierten Systeme (Klassifikation/ Taxonomie, Begriffs-/Themendiagramme, Ontologien) den alphabetisch angeordneten, wortbasierten (Schlagwortlisten, thesaurusartige Schlagwortsysteme und Thesauren im eigentlichen Sinn) gegenüber, was dem Leser weitere Einordnungshilfen schafft. Die Anwendungsmöglichkeiten von Thesauren als Mittel der Erschliessung (auch als Quelle für Metadatenangaben bei elektronischen bzw. Web-Dokumenten) und der Recherche (Suchformulierung, Anfrageerweiterung, Browsing und Navigieren) kommen ebenso zur Sprache wie die bei der Verwendung natürlichsprachiger Indexierungssysteme auftretenden Probleme. Mit Beispielen wird ausdrücklich auf die mehr oder weniger starke fachliche Spezialisierung der meisten dieser Vokabularien hingewiesen, wobei auch Informationsquellen über Thesauren (z.B. www.taxonomywarehouse.com) sowie Thesauren für nicht-textuelle Ressourcen kurz angerissen werden.
In den stärker ins Detail gehenden Kapiteln weist Broughton zunächst auf die Bedeutung des systematischen Teils eines Thesaurus neben dem alphabetischen Teil hin und erläutert dann die Elemente des letzteren, wobei neben den gängigen Thesaurusrelationen auch die Option der Ausstattung der Einträge mit Notationen eines Klassifikationssystems erwähnt wird. Die Thesaurusrelationen selbst werden später noch in einem weiteren Kapitel ausführlicher diskutiert, wobei etwa auch die polyhierarchische Beziehung thematisiert wird. Zwei Kapitel zur Vokabularkontrolle führen in Aspekte wie Behandlung von Synonymen, Vermeidung von Mehrdeutigkeit, Wahl der bevorzugten Terme sowie die Formen von Thesauruseinträgen ein (grammatische Form, Schreibweise, Zeichenvorrat, Singular/Plural, Komposita bzw. deren Zerlegung usw.). Insgesamt acht Kapitel - in der Abfolge mit den bisher erwähnten Abschnitten didaktisch geschickt vermischt - stehen unter dem Motto "Building a thesaurus". Kurz zusammengefasst, geht es dabei um folgende Tätigkeiten und Prozesse: - Sammlung des Vokabulars unter Nutzung entsprechender Quellen; - Termextraktion aus den Titeln von Dokumenten und Probleme hiebei; - Analyse des Vokabulars (Facettenmethode); - Einbau einer internen Struktur (Facetten und Sub-Facetten, Anordnung der Terme); - Erstellung einer hierarchischen Struktur und deren Repräsentation; - Zusammengesetzte Themen bzw. Begriffe (Facettenanordnung: filing order vs. citation order); - Konvertierung der taxonomischen Anordnung in ein alphabetisches Format (Auswahl der Vorzugsbegriffe, Identifizieren hierarchischer Beziehungen, verwandter Begriffe usw.); - Erzeugen der endgültigen Thesaurus-Einträge.
Weitere Rez. in: New Library World 108(2007) nos.3/4, S.190-191 (K.V. Trickey): "Vanda has provided a very useful work that will enable any reader who is prepared to follow her instruction to produce a thesaurus that will be a quality language-based subject access tool that will make the task of information retrieval easier and more effective. Once again I express my gratitude to Vanda for producing another excellent book." - Electronic Library 24(2006) no.6, S.866-867 (A.G. Smith): "Essential thesaurus construction is an ideal instructional text, with clear bullet point summaries at the ends of sections, and relevant and up to date references, putting thesauri in context with the general theory of information retrieval. But it will also be a valuable reference for any information professional developing or using a controlled vocabulary." - KO 33(2006) no.4, S.215-216 (M.P. Satija)

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Abstract

This is a comparative analysis of the term ontology, used in the computer science domain, with the term thesaurus, used in the information science domain. The aim of the study is to establish the main convergence points of these two knowledge representation instruments and to point out their differences. In order to fulfill this goal an analytical-Synthetic method was applied to extract the meaning underlying each of the selected definitions of the instruments. The definitions were obtained from texts weIl accepted by the research community from both areas. The definitions were applied to a KWIC system in order to rotate the terms that were examined qualitatively and quantitatively. We concluded that thesauri and ontologies operate at the same knowledge level, the epistemological level, in spite of different origins and purposes.

Content

"Thesaurus" definitions taken from the information science literature "A thesaurus is a controlled vocabulary arranged in a known order and structured so that equivalence, homographic, hierarchical, and associative relationships among terms are displayed clearly and identified by standardized relationship indicators that are employed reciprocally." (ANSI/NISO Z39-19-1993) "Thesaurus is a specialized, normalized, postcoordinate language used for documentaries means, where the linguistic elements that composes it - single or composed terms - are related among themselves syntactically and semantically." (Translated into English by the authors from the original in Portuguese: Currás 1995, 88.) "[...] an authority file, which can lead the user from one concept to another via various heuristic or intuitive paths." (Howerton 1965 apud Gilchrist 1971, 5) " [...] is a lexical authority list, without notation, which differs from an alphabetical subject heading list in that the lexical units, being smaller, are more amenable to post-coordinate indexing." (Gilchrist 1971,2) [...] "a dynamic controlled vocabulary of terms related semantically and by generic relation covering a specific knowledge domain." (Translated into English by the authors from the original in Portuguese: UNESCO 1973, 6.) [...] "a terminological control device used in the translation of the natural language of the documents, from the indexers or from the users in a more restricted system language (documentation language, information language)." (Translated into English by the authors from the original in Portuguese: UNESCO 1973,6.)
"Ontologies" definitions taken from the computer science literature "[...] ontology is a representation vocabulary, often specialized to some domain or subject matter." (Chandrasekaran et al. 1999, 1) "[...] ontology is sometimes used to refer to a body of knowledge describing some domain, typically a commonsense knowledge domain, using a representation vocabulary." (Chandrasekaran et al. 1999, 1) "An ontology is a declarative model of the terms and relationships in a domain." (Eriksson et al. 1994, 1) " [...] an ontology is the (unspecified) conceptual system which we may assume to underlie a particular knowledge base." (Guarino and Giaretta 1995, 1) Ontology as a representation of a conceptual system via a logical theory". (Guarino and Giaretta 1995, 1) "An ontology is an explicit specification of a conceptualization." (Gruber 1993, 1) "[...] An ontology is a formal description of entities and their properties, relationships, constraints, behaviors." (Gruninger and Fox 1995, 1) "An ontology is set of terms, associated with definitions in natural language and, if possible, using formal relations and constraints, about some domain of interest ..." (Hovy 1998, 2) "Fach Ontology is a set of terms of interest in a particular information domain, expressed using DL ..." (Mena et al. 1996, 3) "[...] An ontology is a hierarchically structured set of terms for describing a domain that can be used as a skeletal foundation for a knowledge base." (Swartout et al. 1996, 1) "An ontology may take a variety of forms, but necessarily it will include a vocabulary of terms and some specification of their meaning." (Uschold 1996,3) "Ontologies are agreements about shared conceptualizations." (Uschold and Grunninger 1996, 6) "[...] a vocabulary of terms and a specification of their relationships." (Wiederhold 1994, 6)

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Abstract

Thesauri are used to provide controlled vocabularies for resource classification. Their use can greatly assist document discovery because thesauri man date a consistent shared terminology for describing documents. A particular thesauras classifies documents according to an information community's needs. As a result, there are many different thesaural schemas. This has led to a proliferation of schema-specific thesaural systems. In our research, we exploit schematic regularities to design a generic thesaural ontology and specfiy it as a markup language. The language provides a common representational framework in which to encode the idiosyncrasies of specific thesauri. This approach has several advantages: it offers consistent syntax and semantics in which to express thesauri; it allows general purpose thesaural applications to leverage many thesauri; and it supports a single thesaural user interface by which information communities can consistently organise, score and retrieve electronic documents.

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Abstract

A nine-stage procedure to build a thesaurus systematically is presented. Each stage offers exercises to put the theory into practice, using agriculture as the sample topic area. Model solutions are given and discussed.

Type

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Abstract

For years, Mexico has had a distance learning system backed by television-signal-transmitted videos. The change to digital and computer transmission demands organizing the information system and its subject contents through a thesaurus. To prepare the thesaurus, an evaluation of existing thesauri and standards for data exchange was carried out, aimed at retrieving subject contents and scheduling broadcasting. Methodology for evaluating thesauri was proposed, compared with a virtual educational platform and a basic structure for setting up the information system was recommended.

Source

Knowledge organization for a global learning society: Proceedings of the 9th International ISKO Conference, 4-7 July 2006, Vienna, Austria. Hrsg.: G. Budin, C. Swertz u. K. Mitgutsch

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Abstract

A thesaurus and an ontology provide a set of structured terms, phrases, and metadata, often in a hierarchical arrangement, that may be used to index, search, and mine documents. We describe the decisions that should be made when including a term, deciding whether a term should be subdivided into its subclasses, or determining which of more than one set of possible subclasses should be used. Based on retrospective measurements or estimates of future performance when using thesaurus terms in document ordering, decisions are made so as to maximize performance. These decisions may be used in the automatic construction of a thesaurus. The evaluation of an existing thesaurus is described, consistent with the decision criteria developed here. These kinds of user-focused decision-theoretic techniques may be applied to other hierarchical applications, such as faceted classification systems used in information architecture or the use of hierarchical terms in "breadcrumb navigation".

Type

a

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Abstract

Thesauri can be useful resources for indexing and retrieval on the Semantic Web, but often they are not published in RDF/OWL. To convert thesauri to RDF for use in Semantic Web applications and to ensure the quality and utility of the conversion a structured method is required. Moreover, if different thesauri are to be interoperable without complicated mappings, a standard schema for thesauri is required. This paper presents a method for conversion of thesauri to the SKOS RDF/OWL schema, which is a proposal for such a standard under development by W3Cs Semantic Web Best Practices Working Group. We apply the method to three thesauri: IPSV, GTAA and MeSH. With these case studies we evaluate our method and the applicability of SKOS for representing thesauri.