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  • × author_ss:"Robertson, A.M."
  • × author_ss:"Willett, P."
  1. Robertson, A.M.; Willett, P.: Generation of equifrequent groups of words using a genetic algorithm (1994) 0.00 
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    Abstract
    Genetic algorithms are a class of non-deterministic algorithms that derive from Darwinian evolution and that provide good, though not necessarily optimal, solutions to combinatorial problems. We describe their application to the identification of characteristics that occur approximately equifrequently in a database, using two different methods for the creation of the chromosome data structures that lie at the heart of a genetic algortihm. Experiments with files of English and Turkish text suggest that the genetic algorithm developed here can produce results superior to those produced by existing non-deterministic algorithms; however, the results are inferior to those produced by an existing deterministic algorithm
    Type
    a
  2. Jones, G.; Robertson, A.M.; Willett, P.: ¬An introduction to genetic algorithms and to their use in information retrieval (1994) 0.00 
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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
    Type
    a
  3. Ekmekcioglu, F.C.; Robertson, A.M.; Willett, P.: Effectiveness of query expansion in ranked-output document retrieval systems (1992) 0.00 
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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
    Type
    a
  4. Robertson, A.M.; Willett, P.: Applications of n-grams in textual information systems (1998) 0.00 
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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
    Type
    a
  5. 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) 0.00 
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    Abstract
    A range of techniques has been developed for the correction of misspellings in machine readable texts. Discusses the use of such techniques for the identification of words in the sixteenth and seventeenth century titles from the Catalogue of Canterbury Cathedral Library that are most similar to query words in modern English. The experiments used digram matching, non phonetic coding, and dynamic programming methods for spelling correction. These allow very high recall searches to be carried out, although the latter methods are very demanding of computer resources
    Type
    a
  6. Robertson, A.M.; Willett, P.: Identification of word-variants in historical text databases : report for the period October 1990 to September 1992 (1994) 0.00 
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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
  7. Robertson, A.M.; Willett, P.: Use of genetic algorithms in information retrieval (1995) 0.00 
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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

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