-
Jones, G.; Robertson, A.M.; Willett, P.: ¬An introduction to genetic algorithms and to their use in information retrieval (1994)
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- Abstract
- This paper provides an introduction to genetic algorithms, a new approach to the investigation of computationally-intensive problems that may be insoluble using conventional, deterministic approaches. A genetic algorithm takes an initial set of possible starting solutions and then iteratively improves theses solutions using operators that are analogous to those involved in Darwinian evolution. The approach is illusrated by reference to several problems in information retrieval
- Source
- Online and CD-ROM review. 18(1994) no.1, S.3-12
-
Robertson, A.M.; Willett, P.: Identification of word-variants in historical text databases : report for the period October 1990 to September 1992 (1994)
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- Abstract
- Databases of historical texts are increasingly becoming available for end user searching via online or CD-ROM databases. Many of the words in these databases are spelt differently from today with resultant loss of retrieval. The project evaluated a range of techniques that can suggest historical variants of modern language query words, the work deriving from earlier work on spelling correction
- Footnote
- Auch ein Beitrag zu den Problemen des Freitext-Retrieval
-
Robertson, A.M.; Willett, P.: Retrieval techniques for historical English text : searching the sixteenth and seventeenth century titles in the Catalogue of Caterbury Cathedral Library using spelling-correction methods (1992)
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- Source
- Online information 92. Proc. of the 16th Int. Online Information Meeting, London, 8-10.12.1992. Ed. by David I. Raitt
-
Al-Hawamdeh, S.; Smith, G.; Willett, P.; Vere, R. de: Using nearest-neighbour searching techniques to access full-text documents (1991)
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- Abstract
- Summarises the results to date of a continuing programme of research at Sheffield Univ. to investigate the use of nearest-neighbour retrieval algorithms for full text searching. Given a natural language query statement, the research methods result in a ranking of the paragraphs comprising a full text document in order of decreasing similarity with the query, where the similarity for each paragraph is determined by the number of keyword stems that it has in common with the query
- Source
- Online review. 15(1991) nos.3/4, S.173-190
-
Ingwersen, P.; Willett, P.: ¬An introduction to algorithmic and cognitive approaches for information retrieval (1995)
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- Abstract
- This paper provides an over-view of 2, complementary approaches to the design and implementation of information retrieval systems. The first approach focuses on the algorithms and data structures that are needed to maximise the effectiveness and the efficiency of the searches that can be carried out on text databases, while the second adopts a cognitive approach that focuses on the role of the user and of the knowledge sources involved in information retrieval. The paper argues for an holistic view of information retrieval that is capable of encompassing both of these approaches
-
Ekmekcioglu, F.C.; Robertson, A.M.; Willett, P.: Effectiveness of query expansion in ranked-output document retrieval systems (1992)
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- Abstract
- Reports an evaluation of 3 methods for the expansion of natural language queries in ranked output retrieval systems. The methods are based on term co-occurrence data, on Soundex codes, and on a string similarity measure. Searches for 110 queries in a data base of 26.280 titles and abstracts suggest that there is no significant difference in retrieval effectiveness between any of these methods and unexpanded searches
- Theme
- Semantisches Umfeld in Indexierung u. Retrieval
-
Willett, P.: Best-match text retrieval (1993)
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- Abstract
- Provides an introduction to the computational techniques that underlie best match searching retrieval systems. Discusses: problems of traditional Boolean systems; characteristics of best-match searching; automatic indexing; term conflation; matching of documents and queries (dealing with similarity measures, initial weights, relevance weights, and the matching algorithm); and describes operational best-match systems
-
Griffiths, A.; Luckhurst, H.C.; Willett, P.: Using interdocument similarity information in document retrieval systems (1986)
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-
Perry, R.; Willett, P.: ¬A revies of the use of inverted files for best match searching in information retrieval systems (1983)
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-
Ekmekcioglu, F.C.; Willett, P.: Effectiveness of stemming for Turkish text retrieval (2000)
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-
Ellis, D.; Furner-Hines, J.; Willett, P.: Measuring the consistency of assignment of hypertext links in full-text documents (1994)
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- Abstract
- Studies of document retrieval systems have suggested that the degree of consistency in the terms assigned to documents by indexers is positively associated with retrieval effectiveness. The study investigated the consistency of assignment of links in separate hypertext versions of the same full text database assuming that a measure of agreement may be related to the subsequent utility of the resulting hypertext document. Describes the calculations involved in measuring the degree of similarity between pairs of structured objetcs of a certain type (Those that may be represented in graph theoretic form). Initial results show little similarity between the sets of links identified by different people and this finding is comparable with those of studies of inter indexer consistency, where it has been found that there is generally only alow level of agreement between the sets of indexing terms assigned to a document of different indexers
- Source
- Information retrieval: new systems and current research. Proceedings of the 15th Research Colloquium of the British Computer Society Information Retrieval Specialist Group, Glasgow 1993. Ed.: Ruben Leon
-
Robertson, A.M.; Willett, P.: Use of genetic algorithms in information retrieval (1995)
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- Abstract
- Reviews the basic techniques involving genetic algorithms and their application to 2 problems in information retrieval: the generation of equifrequent groups of index terms; and the identification of optimal query and term weights. The algorithm developed for the generation of equifrequent groupings proved to be effective in operation, achieving results comparable with those obtained using a good deterministic algorithm. The algorithm developed for the identification of optimal query and term weighting involves fitness function that is based on full relevance information
-
Robertson, A.M.; Willett, P.: Applications of n-grams in textual information systems (1998)
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- Abstract
- Provides an introduction to the use of n-grams in textual information systems, where an n-gram is a string of n, usually adjacent, characters, extracted from a section of continuous text. Applications that can be implemented efficiently and effectively using sets of n-grams include spelling errors detection and correction, query expansion, information retrieval with serial, inverted and signature files, dictionary look up, text compression, and language identification
- Theme
- Semantisches Umfeld in Indexierung u. Retrieval
-
Ellis, D.; Furner-Hines, J.; Willett, P.: On the creation of hypertext links in full-text documents : measurement of inter-linker consistency (1994)
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- Abstract
- In important stage in the process of retrieval of objects from a hypertext database is the creation of a set of inter-nodal links that are intended to represent the relationships existing between objects; this operation is often undertaken manually, just as index terms are often manually assigned to documents in a conventional retrieval system. Studies of conventional systems have suggested that a degree of consistency in the terms assigned to documents by indexers is positively associated with retrieval effectiveness. It is thus of interest to investigate the consistency of assignment of links in separate hypertext versions of the same full-text document, since a measure of agreement may be related to the subsequent utility of the resulting hypertext databases. The calculation of values indicating the degree of similarity between objects is a technique that has been widely used in the fields of textual and chemical information retrieval; in this paper we describe the application of arithmetic coefficients and topological indices to the measurement of the degree of similarity between the sets of inter-nodal links in hypertext databases. We publish the results of a study in which several different of links are inserted, by different people, between the paragraphs of each of a number of full-text documents. Our results show little similary between the sets of links identified by different people; this finding is comparable with those of studies of inter-indexer consistency, where it has been found that there is generally only a low level of agreement between the sets of idenx terms assigned to a document by different indexers
-
Ellis, D.; Furner, J.; Willett, P.: On the creation of hypertext links in full-text documents : measurement of retrieval effectiveness (1996)
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- Abstract
- An important stage in the process or retrieval of objects from a hypertext database is the creation of a set of internodal links that are intended to represent the relationships existing between objects; this operation is often undertaken manually, just as index terms are often manually assigned to documents in a conventional retrieval system. In an earlier article (1994), the results were published of a study in which several different sets of links were inserted, each by a different person, between the paragraphs of each of a number of full-text documents. These results showed little similarity between the link-sets, a finding that was comparable with those of studies of inter-indexer consistency, which suggest that there is generally only a low level of agreement between the sets of index terms assigned to a document by different indexers. In this article, a description is provided of an investigation into the nature of the relationship existing between (i) the levels of inter-linker consistency obtaining among the group of hypertext databases used in our earlier experiments, and (ii) the levels of effectiveness of a number of searches carried out in those databases. An account is given of the implementation of the searches and of the methods used in the calculation of numerical values expressing their effectiveness. Analysis of the results of a comparison between recorded levels of consistency and those of effectiveness does not allow us to draw conclusions about the consistency - effectiveness relationship that are equivalent to those drawn in comparable studies of inter-indexer consistency
-
Ellis, D.; Furner-Hines, J.; Willett, P.: Measuring the degree of similarity between objects in text retrieval systems (1993)
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- Abstract
- Describes the use of a variety of similarity coefficients in the measurement of the degree of similarity between objects that contain textual information, such as documents, paragraphs, index terms or queries. The work is intended as a preliminary to future investigation of the calculations involved in measuring the degree of similarity between structured objects that may be represented by graph theoretic forms. Descusses the role of similarity coefficients in text retrieval in terms of: document and query similarity; document and document similarity; cocitation analysis; term and term similarity; and the similarity between sets of judgements, such as relevance judgements. Describes several methods for expressing the formulae used to define similarity coefficients and compares their attributes. Concludes with details the characteristics of similarity coefficients; equivalence and monotonicity; consideration of negative matches; geometric analyses; and the meaning of correlation coefficients
-
Artymiuk, P.J.; Spriggs, R.V.; Willett, P.: Graph theoretic methods for the analysis of structural relationships in biological macromolecules (2005)
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- Date
- 22. 7.2006 14:40:10
-
Shaw, R.J.; Willett, P.: On the non-random nature of nearest-neighbour document clusters (1993)
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- Abstract
- It has been suggested that the observed values of retrieval effectiveness that are obtained in searches of files of nearest-neighbour clusters can be explained by assuming that the pairwise inter-document similarities used to construct the clusters have been generated randomly. Such similarities are significantly different from those obtained by a random generation procedure
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Robertson, M.; Willett, P.: ¬An upperbound to the performance of ranked output searching : optimal weighting of query terms using a genetic algorithms (1996)
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- Abstract
- Describes the development of a genetic algorithm (GA) for the assignment of weights to query terms in a ranked output document retrieval system. The GA involves a fitness function that is based on full relevance information, and the rankings resulting from the use of these weights are compared with the Robertson-Sparck Jones F4 retrospective relevance weight
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Clarke, S.J.; Willett, P.: Estimating the recall performance of Web search engines (1997)
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- Abstract
- Reports a comparison of the retrieval effectiveness of the AltaVista, Excite and Lycos Web search engines. Describes a method for comparing the recall of the 3 sets of searches, despite the fact that they are carried out on non identical sets of Web pages. It is thus possible, unlike previous comparative studies of Web search engines, to consider both recall and precision when evaluating the effectiveness of search engines
