Venner, G. M. and Walker, S. Microcomputer networking in libraries II. Vine, 48,1983, 22-26.
Describes the initial stages of the design and development of Okapi and outlines the proposed search functions, file structures and access points.
Mitev, N. and Walker, S. Information retrieval aids in an online public access catalogue: automatic intelligent search sequencing. In: Informatics 8: advanced computational techniques for information retrieval. Proceedings of a conference Oxford, 16-18 April, 1985. Aslib, 1985, 215-225.
Provides a description of the `combinational' search trees.
Mitev, N., Venner, G. and Walker, S. Designing an online public access catalogue: Okapi, a catalogue on a local area network. London: British Library, 1985. (Library and Information Research Report 39).
First major research report on the design, development and evaluation of Okapi as a prototype online public access catalogue, operating on a LAN at the Polytechnic of Central London.
Venner, G., Walker, S. and Mitev, N. Okapi: a prototype online catalogue. Vine, 59, 1985, 3- 13.
Outlines Okapi's philosphy from both functional and users' points of view, describing the user interaction, the system's responses, search sequences and displays. Also summarises evaluation results.
Walker, S. The free language approach to online catalogues: the system. In: P. Bryant (ed). Keyword catalogues and the free language approach. Bath University, Centre for Catalogue Research, 1985.
Jones, R. M. Improving Okapi: transaction log analysis of failed searches in an online catalogue. Vine, 62, 1986, 3-13.
A comprehensive discussion of problem areas in Okapi's search interaction, identified by detailed analysis of transaction logs of failed searches. Describes system modifications and proposed measures to compensate for problems such as user errors, improving recall and clearer interaction.
Walker, S. Ease of use in online catalogues: a plea for the user. In: J. Kinsella (ed). Online Public Access to Library Files: 2nd National Conference, Bath 1986. Elsevier, 1986, 78-89.
Walker, S. Okapi: evaluating and enhancing an experimental online catalog. Library Trends, 35 (4), Spring 1987, 631-645.
Describes Okapi's development and suggests ways of improving subject access by improving the system's functionality and enhancing bibliographic records.
Walker, S. and Jones, R. M. Improving subject retrieval in online catalogues: 1. Stemming, automatic spelling correction and cross reference tables. London: British Library, 1987. (British Library Research Paper 24).
Second research report describing the implementation and evaluation of a new version of Okapi with retrieval aids designed to improve retrieval recall.
Jones, R. M. A comparative evaluation of two online public access catalogues: user opinions about the design of online catalogues. London: British Library, 1988. (British Library Research Paper 39).
A study of users' reactions to Okapi and Libertas, and preliminary assessment of classification browsing as an aid for searching.
Walker, S. Improving subject access painlessly: recent work on the Okapi projects. Program 22 (1), 1988, 21-31.
Outlines Okapi's development and describes techniques designed to improve retrieval: word stemming, automatic cross referencing and automatic spelling correction.
Walker, S. Online catalogues. London: British Library, 1988. (Library and Information Briefing 7).
Walker, S. and de Vere, R. Okapi: developing an intelligently interactive online catalogue. Vine, 71, 1988, 4-11.
Describes the third phase of Okapi's development, which introduces query expansion by relevance feedback and classification browsing.
De Vere, R. A comparison of automatic query expansion facilities in two versions of an online public access catalogue designed for subject searching. MSc Thesis, Loughborough University of Technology, 1988.
Walker, S. The Okapi online catalogue research projects. In: C. Hildreth (ed). The online catalogue: developments and directions. London: Library Association, 1989, 84-106.
A review of the Okapi projects to date.
Walker, S. Interactional aspects of a reference retrieval system using semi-automatic query expansion. In: K. P. Jones (ed). Informatics 10: prospects for intelligent retrieval. Proceedings of a Conference, University of York, 21-23 March 1989. Aslib, 1990, 119-36.
Walker, S. and de Vere, R. Improving subject retrieval in online catalogues: 2. Relevance feedback and query expansion. London: British Library, 1990. (British Library Research Paper 72).
Third major research report on the development of a new version of Okapi and laboratory based evaluation of relevance feedback, automatic query expansion and classification browsing.
In 1989 the Okapi project moved to the Centre for Interactive Systems Research at City University, where the system was established as an evaluation facility to test different aspects of information retrieval. The system was used as a basis for a number of projects funded by British Library Research and Development Department, HEFC Joint Information Systems Committee, ARPA and some support from Fretwell-Downing. A number of student projects were also undertaken based on Okapi. Although the online library catalogue continued to be used as a testbed, the system was also used to search other databases such as INSPEC.
Walker, S. Subject access in online catalogues. In: OPACs and the user. Proceedings of the third Anglo-Nordic seminar, 8-11 April, 1990. London: British Library, 1991, 23-33. (British Library Research Report 6040).
Walker, S. Views on classification as a search tool on a computer. In: Computers in Libraries International, 1991. Proceedings of the 5th Annual Conference on Computers in Libraries, London, Feb. 1991. London: Meckler, 1991, 130-139.
Walker, S. and Hancock-Beaulieu, M. Okapi at City: an evaluation facility for interactive IR. London: British Library, 1991. (British Library Research Report 6056).
Report on live evaluation of automatic query expansion with relevance feedback, on abstracting databases and catalogue records, both in a library setting and on the University network. Also summarises results of a survey of frequent users and a preliminary investigation into developing an adaptive IR system which could learn about individual user's needs.
Goker, A. and McCluskey, T. L. Incremental learning in a probabilistic information retrieval system. In: L.A. Birnbaum and G.C. Collins and (eds). Machine Learning. Proceedings of the Eighth International Workshop on Machine Learning (ML91), Evanston, IL, USA, June 1991. San Mateo, CA: Morgan Kaufmann, 1991. 255-9.
Hancock-Beaulieu, M. New ways for subject searching: the Okapi retrieval system. In: C.J. Armstrong and R.J. Hartley (eds). Database 2000. UKOLUG State-of-the-Art Conference 1992. Oxford: Learned Information, 1992, 51-58.
Hancock-Beaulieu, M. Query expansion: advances in research in online catalogues. Journal of Information Science, 18 (2), 1992. 99-103.
Hancock-Beaulieu, M. and Walker, S. An evaluation of automatic query expansion in an online library catalogue. Journal of Documentation, 48 (4), 1992, 406-21.
Describes the objectives of the live evaluation of automatic query expansion based on relevance feedback, carried out at City University. Discusses evaluation methodologies and reports findings on the use, effectiveness and potential use of query expansion.
Robertson, S. E. and Hancock-Beaulieu, M. On the evaluation of IR systems. Information Processing and Management, 28 (4), 1992, 457-66.
A discussion of methodological issues regarding evaluation in IR, drawing on experiments conducted using the Okapi system.