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Robertson, S.E.: On relevance weight estimation and query expansion (1986)
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- Abstract
- A Bayesian argument is used to suggest modifications to the Robertson/Sparck Jones relevance weighting formula, to accomodate the addition to the query of terms taken from the relevant documents identified during the search
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Robertson, S.E.; Walker, S.; Beaulieu, M.: Laboratory experiments with Okapi : participation in the TREC programme (1997)
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- Abstract
- Briefly reviews the history of laboratory testing of information retrieval systems, focusing on the idea of a general purpose test collection of documents, queries and relevance judgements. Gives an overview of the methods used in TREC (Text Retrieval Conference) which is concerned with an ideal test collection, and discusses the Okapi team's participation in TREC. Also discusses some of the issues surrounding the difficult problem of interactive evaluation in TREC. The reconciliation of the requirements of the laboratory context with the concerns of interactive retrieval has a long way to go
- Footnote
- Contribution to a thematic issue on Okapi and information retrieval research
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- a
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Robertson, S.E.; Beaulieu, M.: Research and evaluation in information retrieval (1997)
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- Abstract
- Offered as a discussion document drawing on the experiences of the Okapi team in developing information retrieval systems. Raises some of the issues currently exercising the information retrieval community in the context of experimentation and evaluation
- Footnote
- Contribution to a thematic issue on Okapi and information retrieval research
- Type
- a
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Robertson, S.E.: Overview of the Okapi projects (1997)
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- Abstract
- Gives a brief description of the Okapi projects and of the work of the centre for Interactive Systems Research in the Department of Information Science at City University, London,UK, where these projects have been developed. Describes firstly one version of an information retrieval system which contains some of the central features of the Okapi projects, and follows this with an indication of the variety of systems now implemented or implementable within the present setup
- Footnote
- Contribution to a thematic issue on Okapi and information retrieval research
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Robertson, S.E.: Some recent theories and models in information retrieval (1980)
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Robertson, S.E.: ¬The probability ranking principle in IR (1977)
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Beaulieu, M.M.; Gatford, M.; Huang, X.; Robertson, S.E.; Walker, S.; Williams, P.: Okapi an TREC-5 (1997)
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Robertson, S.E.: Theories and models in information retrieval (1977)
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- Abstract
- This paper is concerned with recent work in the theory of information retrieval. More particularly, it is concerned with theories which tackle the problem of retrieval performance, in a sense which will be explained. The aim is not an exhaustive survey of such work; rather it is an analysis and synthesis of those contributions which I feel to be important or find interesting
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MacFarlane, A.; McCann, J.A.; Robertson, S.E.: Parallel methods for the update of partitioned inverted files (2007)
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- Abstract
- Purpose - An issue that tends to be ignored in information retrieval is the issue of updating inverted files. This is largely because inverted files were devised to provide fast query service, and much work has been done with the emphasis strongly on queries. This paper aims to study the effect of using parallel methods for the update of inverted files in order to reduce costs, by looking at two types of partitioning for inverted files: document identifier and term identifier. Design/methodology/approach - Raw update service and update with query service are studied with these partitioning schemes using an incremental update strategy. The paper uses standard measures used in parallel computing such as speedup to examine the computing results and also the costs of reorganising indexes while servicing transactions. Findings - Empirical results show that for both transaction processing and index reorganisation the document identifier method is superior. However, there is evidence that the term identifier partitioning method could be useful in a concurrent transaction processing context. Practical implications - There is an increasing need to service updates, which is now becoming a requirement of inverted files (for dynamic collections such as the web), demonstrating that a shift in requirements of inverted file maintenance is needed from the past. Originality/value - The paper is of value to database administrators who manage large-scale and dynamic text collections, and who need to use parallel computing to implement their text retrieval services.
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MacFarlane, A.; McCann, J.A.; Robertson, S.E.: Parallel methods for the generation of partitioned inverted files (2005)
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- Abstract
- Purpose - The generation of inverted indexes is one of the most computationally intensive activities for information retrieval systems: indexing large multi-gigabyte text databases can take many hours or even days to complete. We examine the generation of partitioned inverted files in order to speed up the process of indexing. Two types of index partitions are investigated: TermId and DocId. Design/methodology/approach - We use standard measures used in parallel computing such as speedup and efficiency to examine the computing results and also the space costs of our trial indexing experiments. Findings - The results from runs on both partitioning methods are compared and contrasted, concluding that DocId is the more efficient method. Practical implications - The practical implications are that the DocId partitioning method would in most circumstances be used for distributing inverted file data in a parallel computer, particularly if indexing speed is the primary consideration. Originality/value - The paper is of value to database administrators who manage large-scale text collections, and who need to use parallel computing to implement their text retrieval services.
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Robertson, S.E.; Walker, S.: Some simple effective approximations to the 2-Poisson molde for probabilisitc weighted retrieval (1979)
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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
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- a
