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Robertson, S.E.; Walker, S.; Hancock-Beaulieu, M.M.: Large test collection experiments of an operational, interactive system : OKAPI at TREC (1995)
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- Abstract
- The Okapi system has been used in a series of experiments on the TREC collections, investiganting probabilistic methods, relevance feedback, and query expansion, and interaction issues. Some new probabilistic models have been developed, resulting in simple weigthing functions that take account of document length and within document and within query term frequency. All have been shown to be beneficial when based on large quantities of relevance data as in the routing task. Interaction issues are much more difficult to evaluate in the TREC framework, and no benefits have yet been demonstrated from feedback based on small numbers of 'relevant' items identified by intermediary searchers
- Source
- Information processing and management. 31(1995) no.3, S.345-360
- Theme
- Semantisches Umfeld in Indexierung u. Retrieval
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Walker, S.; DeVere, R.: Improving subject retrieval in online catalogues : T.2: Relevance feedback and query expansion (1990)
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- Content
- 1. Introduction // 2. Query modification through relevance feedback // 3. System design & description 4. Evaluation // 5. Analysis & results // 6. Conclusions and recommendations
- Theme
- Semantisches Umfeld in Indexierung u. Retrieval
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Hancock-Beaulieu, M.; Walker, S.: ¬An evaluation of automatic query expansion in an online library catalogue (1992)
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- Abstract
- An automatic query expansion (AQE) facility in anonline catalogue was evaluated in an operational library setting. The OKAPI experimental system had other features including: ranked output 'best match' keyword searching, automatic stemming, spelling normalisation and cross referencing as well as relevance feedback. A combination of transaction log analysis, search replays, questionnaires and interviews was used for data collection. Findings show that contrary to previous results, AQE was beneficial in a substantial number of searches. Use intentions, the effectiveness of the 'best match' search and user interaction were identified as the main factors affecting the take-up of the query expansion facility
- Theme
- Semantisches Umfeld in Indexierung u. Retrieval
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Walker, S.: Subject access in online catalogues (1991)
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- Abstract
- Discusses some of the methods of subject access to on-line catalohues (OPACs) and argues that none are entirley satisfactory. Describes 2 methods for improving subject access: best match searching; and automatic query expansion application and discusses their feasibility. Mentions emerging application standards for information retrieval and concludes that existing standards are incompatible with most methods for improving standards
- Theme
- Semantisches Umfeld in Indexierung u. Retrieval