Search (6 results, page 1 of 1)

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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.

Theme

Konzeption und Anwendung des Prinzips Thesaurus

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Abstract

The use of thesaurus-based indexing is a common approach for increasing the performance of information retrieval. In this thesis, we examine the suitability of a thesaurus for a given set of information and evaluate improvements of existing thesauri to get better search results. On this area, we focus on two aspects: 1. We demonstrate an analysis of the indexing results achieved by an automatic document indexer and the involved thesaurus. 2. We propose a method for thesaurus evaluation which is based on a combination of statistical measures and appropriate visualization techniques that support the detection of potential problems in a thesaurus. In this chapter, we give an overview of the context of our work. Next, we briefly outline the basics of thesaurus-based information retrieval and describe the Collexis Engine that was used for our experiments. In Chapter 3, we describe two experiments in automatically indexing documents in the areas of medicine and economics with corresponding thesauri and compare the results to available manual annotations. Chapter 4 describes methods for assessing thesauri and visualizing the result in terms of a treemap. We depict examples of interesting observations supported by the method and show that we actually find critical problems. We conclude with a discussion of open questions and future research in Chapter 5.

Theme

Konzeption und Anwendung des Prinzips Thesaurus

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Abstract

Crosswalks between different vocabularies are an indispensable prerequisite for integrated and high quality search scenarios in distributed data environments. Offered through the web and linked with each other they act as a central link so that users can move back and forth between different data sources available online. In the past, crosswalks between different thesauri have primarily been developed manually. In the long run the intellectual updating of such crosswalks requires huge personnel expenses. Therefore, an integration of automatic matching procedures, as for example Ontology Matching Tools, seems an obvious need. On the basis of computer generated correspondences between the Thesaurus for Economics (STW) and the Thesaurus for the Social Sciences (TheSoz) our contribution will explore cross-border approaches between IT-assisted tools and procedures on the one hand and external quality measurements via domain experts on the other hand. The techniques that emerge enable semi-automatically performed vocabulary crosswalks.

Object

Thesaurus Sozialwissenschaften
Standard Thesaurus Wirtschaft

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Abstract

Crosswalks between different vocabularies are an indispensable prerequisite for integrated, high-quality search scenarios in distributed data environments where more than one controlled vocabulary is in use. Offered through the web and linked with each other they act as a central link so that users can move back and forth between different online data sources. In the past, crosswalks between different thesauri have usually been developed manually. In the long run the intellectual updating of such crosswalks is expensive. An obvious solution would be to apply automatic matching procedures, such as the so-called ontology matching tools. On the basis of computer-generated correspondences between the Thesaurus for the Social Sciences (TSS) and the Thesaurus for Economics (STW), our contribution explores the trade-off between IT-assisted tools and procedures on the one hand and external quality evaluation by domain experts on the other hand. This paper presents techniques for semi-automatic development and maintenance of vocabulary crosswalks. The performance of multiple matching tools was first evaluated against a reference set of correct mappings, then the tools were used to generate new mappings. It was concluded that the ontology matching tools can be used effectively to speed up the work of domain experts. By optimizing the workflow, the method promises to facilitate sustained updating of high-quality vocabulary crosswalks.

Object

Thesaurus Wirtschaft
Thesaurus Sozialwissenschaften

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Theme

Konzeption und Anwendung des Prinzips Thesaurus

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Date

15. 3.2011 19:21:22