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  • × author_ss:"Robertson, S.E."
  1. Robertson, S.E.; Walker, S.; Hancock-Beaulieu, M.M.: Large test collection experiments of an operational, interactive system : OKAPI at TREC (1995) 0.00 
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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
  2. MacFarlane, A.; McCann, J.A.; Robertson, S.E.: Parallel methods for the update of partitioned inverted files (2007) 0.00 
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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.
  3. Vechtomova, O.; Karamuftuoglum, M.; Robertson, S.E.: On document relevance and lexical cohesion between query terms (2006) 0.00 
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    Abstract
    Lexical cohesion is a property of text, achieved through lexical-semantic relations between words in text. Most information retrieval systems make use of lexical relations in text only to a limited extent. In this paper we empirically investigate whether the degree of lexical cohesion between the contexts of query terms' occurrences in a document is related to its relevance to the query. Lexical cohesion between distinct query terms in a document is estimated on the basis of the lexical-semantic relations (repetition, synonymy, hyponymy and sibling) that exist between there collocates - words that co-occur with them in the same windows of text. Experiments suggest significant differences between the lexical cohesion in relevant and non-relevant document sets exist. A document ranking method based on lexical cohesion shows some performance improvements.
  4. Robertson, S.E.: On relevance weight estimation and query expansion (1986) 0.00 
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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
    Source
    Journal of documentation. 42(1986), S.182-188
  5. Robertson, S.E.: OKAPI at TREC (1994) 0.00 
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    Abstract
    Paper presented at the Text Retrieval Conference (TREC), Washington, DC, Nov 1992. Describes the OKAPI experimental text information retrieval system in terms of its design principles: the use of simple, robust and easy to use techniques which use best match searching and avoid Boolean logic
  6. Robertson, S.E.; Thompson, C.L.: ¬An operational evaluation of weighting, ranking and relevance feedback via a front-end system (1987) 0.00 
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  7. Robertson, S.E.: Query-document symmetry and dual models (1994) 0.00 
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    Abstract
    The idea that there is some natural symmetry between queries and documents is explained. If symmetry can be assumed, then it lead to a conception of 'dual' models in information retrieval (given a model, we can construct a dual model in which the roles of documents and queries are reversed). But symmetry breaks down in various ways, which may invalidate this construction. If we can construct a dual, it is not obvious that it can be combined with the original
    Source
    Journal of documentation. 50(1994) no.3, S.233-238
  8. Robertson, S.E.; Sparck Jones, K.: Simple, proven approaches to text retrieval (1997) 0.00 
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    Abstract
    This technical note describes straightforward techniques for document indexing and retrieval that have been solidly established through extensive testing and are easy to apply. They are useful for many different types of text material, are viable for very large files, and have the advantage that they do not require special skills or training for searching, but are easy for end users. The document and text retrieval methods described here have a sound theoretical basis, are well established by extensive testing, and the ideas involved are now implemented in some commercial retrieval systems. Testing in the last few years has, in particular, shown that the methods presented here work very well with full texts, not only title and abstracts, and with large files of texts containing three quarters of a million documents. These tests, the TREC Tests (see Harman 1993 - 1997; IP&M 1995), have been rigorous comparative evaluations involving many different approaches to information retrieval. These techniques depend an the use of simple terms for indexing both request and document texts; an term weighting exploiting statistical information about term occurrences; an scoring for request-document matching, using these weights, to obtain a ranked search output; and an relevance feedback to modify request weights or term sets in iterative searching. The normal implementation is via an inverted file organisation using a term list with linked document identifiers, plus counting data, and pointers to the actual texts. The user's request can be a word list, phrases, sentences or extended text.
    Issue
    May, 1997, Update of 1994 and 1996 versions.
    Series
    Technical Report TR356, University of Cambridge, Computer Laboratory
  9. Sparck Jones, K.; Walker, S.; Robertson, S.E.: ¬A probabilistic model of information retrieval : development and comparative experiments - part 1 (2000) 0.00 
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  10. Sparck Jones, K.; Walker, S.; Robertson, S.E.: ¬A probabilistic model of information retrieval : development and comparative experiments - part 2 (2000) 0.00 
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  11. Robertson, S.E.; Walker, S.; Beaulieu, M.: Experimentation as a way of life : Okapi at TREC (2000) 0.00 
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  12. Robertson, S.E.; Walker, S.; Beaulieu, M.M.; Gatford, M.; Payne, A.: Okapi at TREC-4 (1996) 0.00 
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    Imprint
    Gaithersburgh, MD : National Institute of Standards and Technology
  13. Robertson, S.E.: ¬The probability ranking principle in IR (1977) 0.00 
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    Source
    Journal of documentation. 33(1977), S.294-304
  14. Beaulieu, M.M.; Gatford, M.; Huang, X.; Robertson, S.E.; Walker, S.; Williams, P.: Okapi an TREC-5 (1997) 0.00 
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    Imprint
    Gaithersburgh, MD : National Institute of Standards and Technology
  15. Robertson, S.E.: On term selection for query expansion (1990) 0.00 
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    Abstract
    In the framework of a relevance feedback system, term values or term weights may be used to (a) select new terms for inclusion in a query, and/or (b) weight the terms for retrieval purposes once selected. It has sometimes been assumed that the same weighting formula should be used for both purposes. This paper sketches a quantitative argument which suggests that the two purposes require different weighting formulae
    Source
    Journal of documentation. 46(1990) no.4, S.359-364
  16. Robertson, S.E.; Walker, S.: Some simple effective approximations to the 2-Poisson molde for probabilisitc weighted retrieval (1979) 0.00 
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    Source
    Journal of documentation. 35(1979), S.285-295 (???)

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