Search (72 results, page 1 of 4)

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Date

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

Series

Lecture notes in computer science; 2539

Theme

Semantisches Umfeld in Indexierung u. Retrieval

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Abstract

A new search paradigm, in which the primary user activity is the guided exploration of a complex information space rather than the retrieval of items based on precise specifications, is proposed. The author claims that this paradigm is the norm in most practical applications, and that solutions based on traditional search methods are not effective in this context. He then presents a solution based on dynamic taxonomies, a knowledge management model that effectively guides users to reach their goal while giving them total freedom in exploring the information base. Applications, benefits, and current research are discussed.

Date

22. 7.2006 17:56:22

Footnote

Beitrag in einer Special Section "Perspectives on Search User Interfaces: Best Practices and Future Visions"

Theme

Semantisches Umfeld in Indexierung u. Retrieval

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Theme

Konzeption und Anwendung des Prinzips Thesaurus
Semantisches Umfeld in Indexierung u. Retrieval

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Abstract

The digital library system Daffodil is targeted at strategic support of users during the information search process. For searching, exploring and managing digital library objects it provides user-customisable information seeking patterns over a federation of heterogeneous digital libraries. In this paper evaluation results with respect to retrieval effectiveness, efficiency and user satisfaction are presented. The analysis focuses on strategic support for the scientific work-flow. Daffodil supports the whole work-flow, from data source selection over information seeking to the representation, organisation and reuse of information. By embedding high level search functionality into the scientific work-flow, the user experiences better strategic system support due to a more systematic work process. These ideas have been implemented in Daffodil followed by a qualitative evaluation. The evaluation has been conducted with 28 participants, ranging from information seeking novices to experts. The results are promising, as they support the chosen model.

Date

16.11.2008 16:22:48

Series

Lecture notes in computer science; vol.3232

Theme

Semantisches Umfeld in Indexierung u. Retrieval

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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.

Series

Advances in knowledge organization; vol.9

Theme

Konzeption und Anwendung des Prinzips Thesaurus
Semantisches Umfeld in Indexierung u. Retrieval

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Abstract

Humans can make hasty, but generally robust judgements about what a text fragment is, or is not, about. Such judgements are termed information inference. This article furnishes an account of information inference from a psychologistic stance. By drawing an theories from nonclassical logic and applied cognition, an information inference mechanism is proposed that makes inferences via computations of information flow through an approximation of a conceptual space. Within a conceptual space information is represented geometrically. In this article, geometric representations of words are realized as vectors in a high dimensional semantic space, which is automatically constructed from a text corpus. Two approaches were presented for priming vector representations according to context. The first approach uses a concept combination heuristic to adjust the vector representation of a concept in the light of the representation of another concept. The second approach computes a prototypical concept an the basis of exemplar trace texts and moves it in the dimensional space according to the context. Information inference is evaluated by measuring the effectiveness of query models derived by information flow computations. Results show that information flow contributes significantly to query model effectiveness, particularly with respect to precision. Moreover, retrieval effectiveness compares favorably with two probabilistic query models, and another based an semantic association. More generally, this article can be seen as a contribution towards realizing operational systems that mimic text-based human reasoning.

Date

22. 3.2003 19:35:46

Footnote

Beitrag eines Themenheftes: Mathematical, logical, and formal methods in information retrieval

Theme

Semantisches Umfeld in Indexierung u. Retrieval

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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
Semantisches Umfeld in Indexierung u. Retrieval

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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

Theme

Semantisches Umfeld in Indexierung u. Retrieval

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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
Semantisches Umfeld in Indexierung u. Retrieval

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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

Semantisches Umfeld in Indexierung u. Retrieval
Konzeption und Anwendung des Prinzips Thesaurus

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Abstract

This paper addresses the problem of information discovery in large collections of text. For users, one of the key problems in working with such collections is determining where to focus their attention. In selecting documents for examination, users must be able to formulate reasonably precise queries. Queries that are too broad will greatly reduce the efficiency of information discovery efforts by overwhelming the users with peripheral information. In order to formulate efficient queries, a mechanism is needed to automatically alert users regarding potentially interesting information contained within the collection. This paper presents the results of an experiment designed to test one approach to generation of such alerts. The technique of latent semantic indexing (LSI) is used to identify relationships among entities of interest. Entity extraction software is used to pre-process the text of the collection so that the LSI space contains representation vectors for named entities in addition to those for individual terms. In the LSI space, the cosine of the angle between the representation vectors for two entities captures important information regarding the degree of association of those two entities. For appropriate choices of entities, determining the entity pairs with the highest mutual cosine values yields valuable information regarding the contents of the text collection. The test database used for the experiment consists of 150,000 news articles. The proposed approach for alert generation is tested using a counterterrorism analysis example. The approach is shown to have significant potential for aiding users in rapidly focusing on information of potential importance in large text collections. The approach also has value in identifying possible use of aliases.

Source

Proceedings of the Fourth Workshop on Link Analysis, Counterterrorism, and Security, SIAM Data Mining Conference, Bethesda, MD, 20-22 April, 2006. [http://www.siam.org/meetings/sdm06/workproceed/Link%20Analysis/15.pdf]

Theme

Semantisches Umfeld in Indexierung u. Retrieval

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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

Semantisches Umfeld in Indexierung u. Retrieval
Konzeption und Anwendung des Prinzips Thesaurus

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Abstract

The subject of context has received a great deal of attention in the information retrieval (IR) literature over the past decade, primarily in studies of information seeking and IR interactions. Recently, attention to context in IR has expanded to address new problems in new environments. In this paper we outline five overlapping dimensions of context which we believe to be important constituent elements and we discuss how they are related to different issues in IR research. The papers in this special issue are summarized with respect to how they represent work that is being conducted within these dimensions of context. We conclude with future areas of research which are needed in order to fully understand the multidimensional nature of context in IR.

Footnote

Einführung in ein Themenheft: "Issues of context in information retrieval (IR)"

Theme

Semantisches Umfeld in Indexierung u. Retrieval

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Abstract

Based on an in-depth analysis of existing approaches in building ontology-based query systems we discuss and compare the methods, approaches to be used in current query systems using Ontology or the Semantic Web techniques. This paper identifies various relevant research directions in ontology-based querying research. Based on the results of our investigation we summarise the state of the art ontology-based query/search and name areas of further research activities.

Theme

Semantisches Umfeld in Indexierung u. Retrieval

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Abstract

An experiment was conducted to see how relevance feedback could be used to build and adjust profiles to improve the performance of filtering systems. Data was collected during the system interaction of 18 graduate students with SIFTER (Smart Information Filtering Technology for Electronic Resources), a filtering system that ranks incoming information based on users' profiles. The data set came from a collection of 6000 records concerning consumer health. In the first phase of the study, three different modes of profile acquisition were compared. The explicit mode allowed users to directly specify the profile; the implicit mode utilized relevance feedback to create and refine the profile; and the combined mode allowed users to initialize the profile and to continuously refine it using relevance feedback. Filtering performance, measured in terms of Normalized Precision, showed that the three approaches were significantly different ( [small alpha, Greek] =0.05 and p =0.012). The explicit mode of profile acquisition consistently produced superior results. Exclusive reliance on relevance feedback in the implicit mode resulted in inferior performance. The low performance obtained by the implicit acquisition mode motivated the second phase of the study, which aimed to clarify the role of context in relevance feedback judgments. An inductive content analysis of thinking aloud protocols showed dimensions that were highly situational, establishing the importance context plays in feedback relevance assessments. Results suggest the need for better representation of documents, profiles, and relevance feedback mechanisms that incorporate dimensions identified in this research.

Footnote

Beitrag in einem Themenheft: "Issues of context in information retrieval (IR)"

Theme

Semantisches Umfeld in Indexierung u. Retrieval

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Theme

Semantisches Umfeld in Indexierung u. Retrieval

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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.

Theme

Semantisches Umfeld in Indexierung u. Retrieval

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Abstract

The equivalence of semantic networks with spreading activation and vector spaces with dot product is investigated under ranked retrieval. Semantic networks are viewed as networks of concepts organized in terms of abstraction and packaging relations. It is shown that the two models can be effectively constructed from each other. A formal method is suggested to analyze the models in terms of their relative performance in the same universe of objects

Theme

Semantisches Umfeld in Indexierung u. Retrieval

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Abstract

While surprisingly little has been written about context at a meaningful level, context is central to most theoretical approaches to information seeking. In this essay I explore in more detail three senses of context. First, I look at context as equivalent to the situation in which a process is immersed. Second, I discuss contingency approaches that detail active ingredients of the situation that have specific, predictable effects. Third, I examine major frameworks for meaning systems. Then, I discuss how a deeper appreciation of context can enhance our understanding of the process of information seeking by examining two vastly different contexts in which it occurs: organizational and cancer-related, an exemplar of everyday life information seeking. This essay concludes with a discussion of the value that can be added to information seeking research and theory as a result of a deeper appreciation of context, particularly in terms of our current multi-contextual environment and individuals taking an active role in contextualizing.

Theme

Semantisches Umfeld in Indexierung u. Retrieval

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Abstract

In this paper, we compare a well-known semantic spacemodel, Latent Semantic Analysis (LSA) with another model, Hyperspace Analogue to Language (HAL) which is widely used in different area, especially in automatic query refinement. We conduct this comparative analysis to prove our hypothesis that with respect to ability of extracting the lexical information from a corpus of text, LSA is quite similar to HAL. We regard HAL and LSA as black boxes. Through a Pearson's correlation analysis to the outputs of these two black boxes, we conclude that LSA highly co-relates with HAL and thus there is a justification that LSA and HAL can potentially play a similar role in the area of facilitating automatic query refinement. This paper evaluates LSA in a new application area and contributes an effective way to compare different semantic space models.

Series

Lecture notes in computer science; vol. 3314

Theme

Semantisches Umfeld in Indexierung u. Retrieval