Search (34 results, page 1 of 2)

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Abstract

The study reported here investigated the query expansion behavior of end-users interacting with a thesaurus-enhanced search system on the Web. Two groups, namely academic staff and postgraduate students, were recruited into this study. Data were collected from 90 searches performed by 30 users using the OVID interface to the CAB abstracts database. Data-gathering techniques included questionnaires, screen capturing software, and interviews. The results presented here relate to issues of search-topic and search-term characteristics, number and types of expanded queries, usefulness of thesaurus terms, and behavioral differences between academic staff and postgraduate students in their interaction. The key conclusions drawn were that (a) academic staff chose more narrow and synonymous terms than did postgraduate students, who generally selected broader and related terms; (b) topic complexity affected users' interaction with the thesaurus in that complex topics required more query expansion and search term selection; (c) users' prior topic-search experience appeared to have a significant effect on their selection and evaluation of thesaurus terms; (d) in 50% of the searches where additional terms were suggested from the thesaurus, users stated that they had not been aware of the terms at the beginning of the search; this observation was particularly noticeable in the case of postgraduate students.

Date

22. 7.2006 16:32:43

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Theme

Konzeption und Anwendung des Prinzips Thesaurus

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Abstract

Das System ALEPH 500 (Version 14.2) bietet den Benutzern mit der Weiterentwicklung des "Multilingualen Thesaurus" verfeinerte Recherchefunktionen an, z.B. - Erhöhung der Treffsicherheit - Ausschluss von nicht zutreffenden Suchergebnissen - Aufspüren aller für die Suche relevanter Titel - Sprachunabhängige Suche - Beziehungen zwischen Begriffen. Im ALEPH 500-Web OPAC wird der Thesaurus in zwei Fenstern angezeigt. Links ist der Thesaurus-Baum mit Hierarchien und Begriffsbeziehungen abgebildet. Parallel dazu werden rechts die Informationen zum ausgewählten Deskriptor dargestellt. Von diesem Fenster aus sind weitere thesaurusbezogene Funktionen ausführbar. Der Thesaurus ist direkt mit dem Titelkatalog verknüpft. Somit kann sich der Benutzer vom gewählten Deskriptor ausgehend sofort die vorhandenen Titel im OPAC anzeigen lassen. Sowohl die Einzelrecherche über einen Deskriptor als auch die Top DownRecherche über einen Thesaurus-Baumzweig werden im Suchverlauf des Titelkatalogs mitgeführt. Die Recherche kann mit den bekannten Funktionen in ALEPH 500 erweitert, eingeschränkt, modifiziert oder als SDI-Profil abgelegt werden. Erfassung und Pflege des Thesaurusvokabublars erfolgen im Katalogisierungsmodul unter Beachtung allgemein gültiger Regeln mit Hilfe maßgeschneiderter Schablonen, die modifizierbar sind. Durch entsprechende Feldbelegungen können die vielfältigen Beziehungen eines Deskriptors abgebildet sowie Sprachvarianten hinterlegt werden. Hintergrundverknüpfungen sorgen dafür, dass sich Änderungen im Thesaurus sofort und direkt auf die bibliographischen Daten auswirken.

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Abstract

Das System ALEPH 500 (Version 14.2) bietet den Benutzern mit der Weiterentwicklung des "Multilingualen Thesaurus" verfeinerte Recherchefunktionen an, z.B. - Erhöhung der Treffsicherheit - Ausschluss von nicht zutreffenden Suchergebnissen - Aufspüren aller für die Suche relevanter Titel - Sprachunabhängige Suche - Beziehungen zwischen Begriffen. Im ALEPH 500-Web OPAC wird der Thesaurus in zwei Fenstern angezeigt. Links ist der Thesaurus-Baum mit Hierarchien und Begriffsbeziehungen abgebildet. Parallel dazu werden rechts die Informationen zum ausgewählten Deskriptor dargestellt. Von diesem Fenster aus sind weitere thesaurusbezogene Funktionen ausführbar. Der Thesaurus ist direkt mit dem Titelkatalog verknüpft. Somit kann sich der Benutzer vom gewählten Deskriptor ausgehend sofort die vorhandenen Titel im OPAC anzeigen lassen. Sowohl die Einzelrecherche über einen Deskriptor als auch die Top DownRecherche über einen Thesaurus-Baumzweig werden im Suchverlauf des Titelkatalogs mitgeführt. Die Recherche kann mit den bekannten Funktionen in ALEPH 500 erweitert, eingeschränkt, modifiziert oder als SDI-Profil abgelegt werden. Erfassung und Pflege des Thesaurusvokabublars erfolgen im Katalogisierungsmodul unter Beachtung allgemein gültiger Regeln mit Hilfe maßgeschneiderter Schablonen, die modifizierbar sind. Durch entsprechende Feldbelegungen können die vielfältigen Beziehungen eines Deskriptors abgebildet sowie Sprachvarianten hinterlegt werden. Hintergrundverknüpfungen sorgen dafür, dass sich Änderungen im Thesaurus sofort und direkt auf die bibliographischen Daten auswirken.

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Abstract

Purpose - The purpose of this paper is to explore query expansion via conceptual distance in thesaurus indexed collections Design/methodology/approach - An extract of the National Museum of Science and Industry's collections database, indexed with the Getty Art and Architecture Thesaurus (AAT), was the dataset for the research. The system architecture and algorithms for semantic closeness and the matching function are outlined. Standalone and web interfaces are described and formative qualitative user studies are discussed. One user session is discussed in detail, together with a scenario based on a related public inquiry. Findings are set in context of the literature on thesaurus-based query expansion. This paper discusses the potential of query expansion techniques using the semantic relationships in a faceted thesaurus. Findings - Thesaurus-assisted retrieval systems have potential for multi-concept descriptors, permitting very precise queries and indexing. However, indexer and searcher may differ in terminology judgments and there may not be any exactly matching results. The integration of semantic closeness in the matching function permits ranked results for multi-concept queries in thesaurus-indexed applications. An in-memory representation of the thesaurus semantic network allows a combination of automatic and interactive control of expansion and control of expansion on individual query terms. Originality/value - The application of semantic expansion to browsing may be useful in interface options where thesaurus structure is hidden.

Object

Art and architecture thesaurus

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Abstract

Purpose - This paper seeks to report an investigation into the ways in which end-users perceive a thesaurus-enhanced search interface, in particular thesaurus and search interface usability. Design/methodology/approach - Thirty academic users, split between staff and postgraduate students, carrying out real search requests were observed during this study. Users were asked to comment on a range of thesaurus and interface characteristics including: ease of use, ease of learning, ease of browsing and navigation, problems and difficulties encountered while interacting with the system, and the effect of browsing on search term selection. Findings - The results suggest that interface usability is a factor affecting thesaurus browsing/navigation and other information-searching behaviours. Academic staff viewed the function of a thesaurus as being useful for narrowing down a search and providing alternative search terms, while postgraduates stressed the role of the thesaurus for broadening searches and providing new terms. Originality/value - The paper provides an insight into the ways in which end-users make use of and interact with a thesaurus-enhanced search interface. This area is new since previous research has particularly focused on how professional searchers and librarians make use of thesauri and thesaurus-enhanced search interfaces. The research reported here suggests that end-users with varying levels of domain knowledge are able to use thesauri that are integrated into search interfaces. It also provides design implications for search interface developers as well as information professionals who are involved in teaching online searching.

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Abstract

The use of thesaurus-enhanced search tools is an the increase. This paper provides an insight into end-users interaction with and perceptions of such tools. In particular the overlap between users' initial query formulation and thesaurus structures is investigated. This investigation involved the performance of genuine search tasks an the CAB Abstracts database by academic users in the domain of veterinary medicine. The perception of these users regarding the nature and usefulness of the terms suggested from the thesaurus during the search interaction is reported. The results indicated that around 80% of terms entered were matched either exactly or partially to thesaurus terms. Users found over 90% of the terms suggested to be close to their search topics and where terms were selected they indicated that around 50% were to support a 'narrowing down' activity. These findings have implications for the design of thesaurus-enhanced interfaces.

Theme

Konzeption und Anwendung des Prinzips Thesaurus

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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

Theme

Konzeption und Anwendung des Prinzips Thesaurus

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Abstract

The authors present a model of information searching in thesaurus-enhanced search systems, intended as a reference model for system developers. The model focuses on user-system interaction and charts the specific stages of searching an indexed collection with a thesaurus. It was developed based on literature, findings from empirical studies, and analysis of existing systems. The model describes in detail the entities, processes, and decisions when interacting with a search system augmented with a thesaurus. A basic search scenario illustrates this process through the model. Graphical and textual depictions of the model are complemented by a concise matrix representation for evaluation purposes. Potential problems at different stages of the search process are discussed, together with possibilities for system developers. The aim is to set out a framework of processes, decisions, and risks involved in thesaurus-based search, within which system developers can consider potential avenues for support.

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Abstract

This study explores how experts and novices in pedagogics expanded queries supported by the ERIC thesaurus, and how this was connected to the search effectiveness in an easy and a difficult search task. The expert group consisted of 15 undergraduates in pedagogy and the novice group of 15 students with no previous studies in this field. Their search logs were recorded and a pre- and post-search interview was conducted. The results show that the number and type of terms selected from the thesaurus for expansion by experts improved search effectiveness, whereas there were no connections between the use of thesaurus and improvement of effectiveness among novices. The effectiveness of expansions varied between the facets of the queries. Thus, a vital condition for benefiting from a thesaurus in query expansion to improve search results is sufficient familiarity with the search topic. The results suggest also that it is not in the first place the number of terms used in expansion, but their type and quality that are crucial for search success.

Theme

Konzeption und Anwendung des Prinzips Thesaurus

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Abstract

There are many advantages for Digital Libraries in indexing with classifications or thesauri, but some current disincentive in the lack of flexible retrieval tools that deal with compound descriptors. This demonstration of a research prototype illustrates a matching function for compound descriptors, or multi-concept subject headings, that does not rely on exact matching but incorporates term expansion via thesaurus semantic relationships to produce ranked results that take account of missing and partially matching terms. The matching function is based on a measure of semantic closeness between terms.The work is part of the EPSRC funded FACET project in collaboration with the UK National Museum of Science and Industry (NMSI) which includes the National Railway Museum. An export of NMSI's Collections Database is used as the dataset for the research. The J. Paul Getty Trust's Art and Architecture Thesaurus (AAT) is the main thesaurus in the project. The AAT is a widely used thesaurus (over 120,000 terms). Descriptors are organised in 7 facets representing separate conceptual classes of terms.The FACET application is a multi tiered architecture accessing a SQL Server database, with an OLE DB connection. The thesauri are stored as relational tables in the Server's database. However, a key component of the system is a parallel representation of the underlying semantic network as an in-memory structure of thesaurus concepts (corresponding to preferred terms). The structure models the hierarchical and associative interrelationships of thesaurus concepts via weighted poly-hierarchical links. Its primary purpose is real-time semantic expansion of query terms, achieved by a spreading activation semantic closeness algorithm. Queries with associated results are stored persistently using XML format data. A Visual Basic interface combines a thesaurus browser and an initial term search facility that takes into account equivalence relationships. Terms are dragged to a direct manipulation Query Builder which maintains the facet structure.

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Abstract

Purpose - To evaluate the extent to which familiarity with search topics affects the ways in which users select and browse search terms in a thesaurus-enhanced search setting. Design/methodology/approach - An experimental methodology was adopted to study users' search behaviour in an operational information retrieval environment. Findings - Topic familiarity and subject knowledge influence some search and interaction behaviours. Searches involving moderately and very familiar topics were associated with browsing around twice as many thesaurus terms as was the case for unfamiliar topics. Research limitations/implications - Some search behaviours such as thesaurus browsing and term selection could be used as an indication of user levels of topic familiarity. Practical implications - The results of this study provide design implications as to how to develop personalized search interfaces where users with varying levels of familiarity with search topics can carry out searches. Originality/value - This paper establishes the importance of topic familiarity characteristics and the effects of those characteristics on users' interaction with search interfaces enhanced with semantic tools such as thesauri.

Theme

Konzeption und Anwendung des Prinzips Thesaurus

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Abstract

This paper provides a review of the literature related to the application of domain-specific thesauri in the search and retrieval process. Focusing an studies that adopt a user-centred approach, the review presents a survey of the methodologies and results from empirical studies undertaken an the use of thesauri as sources of term selection for query formulation and expansion during the search process. It summarises the ways in which domain-specific thesauri from different disciplines have been used by various types of users and how these tools aid users in the selection of search terms. The review consists of two main sections: first, studies an thesaurus-aided search term selection; and second, studies dealing with query expansion using thesauri. Both sections are illustrated with case studies that have adopted a user-centred approach.

Theme

Konzeption und Anwendung des Prinzips Thesaurus

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Abstract

Seit 3. Juli 2006 stellt das ZPID eine verbesserte Suchoberfläche für die Recherche in der bibliographischen Psychologie-Datenbank PSYNDEX zur Verfügung. Hauptmerkmal der neuen Version 1.1 des 'ZPID-Retrieval für PSYNDEX' ist die Einbindung von 'PSYNDEX Terms', dem kontrollierten Wortschatz der psychologischen Fachsprache. PSYNDEX Terms basiert auf dem 'Thesaurus of Psychological Index Terms' der American Psychological Association (APA) und enthält im Moment über 5.400 Deskriptoren. Zu jedem Deskriptor werden ggf. Oberbegriffe, Unterbegriffe und verwandte Begriffe angezeigt. Wer die Suchoberfläche nutzt, kann entweder im Thesaurus blättern oder gezielt nach Thesaurusbegriffen suchen. Kommt der eigene frei gewählte Suchbegriff nicht im Thesaurus vor, macht das System selbsttätig Vorschläge für passende Thesaurusbegriffe. DerThesaurus ist komplett zweisprachig (deutsch/englisch) implementiert, sodass er auch als Übersetzungshilfe dient. Weitere Verbesserungen der Suchoberfläche betreffen die Darstellbarkeit in unterschiedlichen Web-Browsern mit dem Ziel der Barrierefreiheit, die Erweiterung der OnlineHilfe mit Beispielen für erfolgreiche Suchstrategien, die Möglichkeit, zu speziellen Themen vertiefte Informationen abzurufen (den Anfang machen psychologische Behandlungsprogramme) und die Bereitstellung eines Export-Filters für EndNote. Zielgruppe des ZPID-Retrieval sind Einzelpersonen, die keinen institutionellen PSYNDEX-Zugang, z.B. am Campus einer Universität, nutzen können. Sie können das kostenpflichtige Retrieval direkt online erwerben und werden binnen weniger Minuten freigeschaltet. Kunden mit existierendem Vertrag kommen automatisch in den Genuss der verbesserten Suchoberfläche.

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Abstract

The Medical professionals and researchers need information from reputable sources to accomplish their work. Unfortunately, the Web has a large number of documents that are irrelevant to their work, even those documents that purport to be "medically-related." This paper describes an architecture designed to integrate advanced searching and indexing algorithms, an automatic thesaurus, or "concept space," and Kohonen-based Self-Organizing Map (SOM) technologies to provide searchers with finegrained results. Initial results indicate that these systems provide complementary retrieval functionalities. HelpfulMed not only allows users to search Web pages and other online databases, but also allows them to build searches through the use of an automatic thesaurus and browse a graphical display of medical-related topics. Evaluation results for each of the different components are included. Our spidering algorithm outperformed both breadth-first search and PageRank spiders an a test collection of 100,000 Web pages. The automatically generated thesaurus performed as well as both MeSH and UMLS-systems which require human mediation for currency. Lastly, a variant of the Kohonen SOM was comparable to MeSH terms in perceived cluster precision and significantly better at perceived cluster recall.

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Abstract

There are many advantages for Digital Libraries in indexing with classifications or thesauri, but some current disincentive in the lack of flexible retrieval tools that deal with compound descriptors. This paper discusses a matching function for compound descriptors, or multi-concept subject headings, that does not rely an exact matching but incorporates term expansion via thesaurus semantic relationships to produce ranked results that take account of missing and partially matching terms. The matching function is based an a measure of semantic closeness between terms, which has the potential to help with recall problems. The work reported is part of the ongoing FACET project in collaboration with the National Museum of Science and Industry and its collections database. The architecture of the prototype system and its Interface are outlined. The matching problem for compound descriptors is reviewed and the FACET implementation described. Results are discussed from scenarios using the faceted Getty Art and Architecture Thesaurus. We argue that automatic traversal of thesaurus relationships can augment the user's browsing possibilities. The techniques can be applied both to unstructured multi-concept subject headings and potentially to more syntactically structured strings. The notion of a focus term is used by the matching function to model AAT modified descriptors (noun phrases). The relevance of the approach to precoordinated indexing and matching faceted strings is discussed.

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Abstract

"Thesaurus linguae latinae" - so heißt eine der frühesten Wort-Sammlungen. Seit Alters her beschäftigen sich Menschen mit der qualifizierten Aufbereitung von Information. Noch älter ist sogar das Konzept der Ontologie (wörtlich: die "Lehre vom Sein"), die sich als Disziplin der Philosophie bereits seit Aristoteles (384-322 v. Chr.) mit einer objektivistischen Beschreibung der Wirklichkeit beschäftigt. Ontologien - als Disziplin des modernen Wissensmanagements-sind eine Methode, in möglichst kompakter Form, d.h. unter Verwendung von Konzepten in verschiedenen Meta-Ebenen die reale Welt zu beschreiben. Thesaurus und Ontologie stellen zwei Konzepte dar, die auch heute noch in der Wissenschaft - und in jüngster Zeit mit zunehmender Bedeutung auch in der Wirtschaft - im Bereich des Informationsund Wissensmanagements zum Einsatz kommen. Beide spannen gewissermaßen den konzeptionellen Bogen, an dem sich ein pragmatisches Wissensmanagement heutzutage ausrichtet und sich in Form sogenannter semantischer Netze - auch Wissensnetze genannt - wiederfindet.

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Abstract

From the user's perspective, however, it is still difficult to use current information retrieval systems. Users frequently have problems expressing their information needs and translating those needs into queries. This is partly due to the fact that information needs cannot be expressed appropriately in systems terms. It is not unusual for users to input search terms that are different from the index terms information systems use. Various methods have been proposed to help users choose search terms and articulate queries. One widely used approach is to incorporate into the information system a thesaurus-like component that represents both the important concepts in a particular subject area and the semantic relationships among those concepts. Unfortunately, the development and use of thesauri is not without its own problems. The thesaurus employed in a specific information system has often been developed for a general subject area and needs significant enhancement to be tailored to the information system where it is to be used. This thesaurus development process, if done manually, is both time consuming and labor intensive. Usage of a thesaurus in searching is complex and may raise barriers for the user. For illustration purposes, let us consider two scenarios of thesaurus usage. In the first scenario the user inputs a search term and the thesaurus then displays a matching set of related terms. Without an overview of the thesaurus - and without the ability to see the matching terms in the context of other terms - it may be difficult to assess the quality of the related terms in order to select the correct term. In the second scenario the user browses the whole thesaurus, which is organized as in an alphabetically ordered list. The problem with this approach is that the list may be long, and neither does it show users the global semantic relationship among all the listed terms.
Nevertheless, because thesaurus use has shown to improve retrieval, for our method we integrate functions in the search interface that permit users to explore built-in search vocabularies to improve retrieval from digital libraries. Our method automatically generates the terms and their semantic relationships representing relevant topics covered in a digital library. We call these generated terms the "concepts", and the generated terms and their semantic relationships we call the "concept space". Additionally, we used a visualization technique to display the concept space and allow users to interact with this space. The automatically generated term set is considered to be more representative of subject area in a corpus than an "externally" imposed thesaurus, and our method has the potential of saving a significant amount of time and labor for those who have been manually creating thesauri as well. Information visualization is an emerging discipline and developed very quickly in the last decade. With growing volumes of documents and associated complexities, information visualization has become increasingly important. Researchers have found information visualization to be an effective way to use and understand information while minimizing a user's cognitive load. Our work was based on an algorithmic approach of concept discovery and association. Concepts are discovered using an algorithm based on an automated thesaurus generation procedure. Subsequently, similarities among terms are computed using the cosine measure, and the associations among terms are established using a method known as max-min distance clustering. The concept space is then visualized in a spring embedding graph, which roughly shows the semantic relationships among concepts in a 2-D visual representation. The semantic space of the visualization is used as a medium for users to retrieve the desired documents. In the remainder of this article, we present our algorithmic approach of concept generation and clustering, followed by description of the visualization technique and interactive interface. The paper ends with key conclusions and discussions on future work.

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Date

22. 2.2003 17:25:39
22. 2.2003 18:17:40