Search results

This article reports an attempt to understand how a new non‐Boolean ranked output online search facility works. In December 1993, Data‐Star Dialog released a relevance ranking tool known as TARGET (Dialog 1993b). There is considerable research activity into text retrieval using ranking methods, as instanced by the TREC experiments (Harman 1993), and professional online searchers may wish to know exactly what the ranking algorithm does in order to be able to exploit the facility to best advantage. Though it has not been possible to ‘crack’ the algorithm to the level of calculating its match to the nearest per cent, it is possible to see three or four factors at work in the way TARGET produces items ranked in decreasing order of match with a query. It is emphasised that the analysis presented here is based only on records from one bibliographic database. A more extensive and comparative study of bibliographic and full‐text databases would be needed to provide universal and definitive findings.

Reports a laboratory comparison of the effectiveness and efficiency of five index languages in the subject area of library and information science; three post‐co‐ordinate languages, Compressed Term, Uncontrolled, and Hierarchically Structured, and two pre‐co‐ordinate ones, Hierarchically Structured and Relational Indexing. Eight test comparisons were made, and factors studied were index language specificity and linkage, indexing specificity and exhaustivity, method of co‐ordination, the precision devices of partitioning and relational operators, and the provision of context in the search file. Full details of the test and retrieval results are presented.

After considering the search process and functions of index entries, a classification of entry types is offered, based on index term context, predominant term order, and between‐term function words. Then a multiple entry generation scheme is described, comprising rules for term manipulation, input and output. After discussing access points and cross reference measures, a preliminary linguistic analysis is given, showing links with psycholinguistics. The study forms the basis of a current laboratory investigation (EPSILON) into a number of entry types.

Term position information, as provided in some Boolean systems in the form of field restriction and term proximity, is reviewed and its value assessed. Non‐Boolean retrieval in the form of the ranked output experiment has not so far used term position information but has concentrated on schemes of term weighting. The use of term proximity devices is proposed here by analogy with Boolean techniques and seven algorithms are devised to incorporate the ideas of sentence matching, proximate terms, term order specification and term distance computations. It is hypothesised that term position will act as a precision device. A new search experiment is then described in which a test collection is processed into sentences and then output ranking using term position is obtained. Results are given for five algorithms compared against quorum searching as the benchmark. The best result increased the precision ratio by 18% and used proximate matching term pairs in sentences plus a distance component.

The task of inputting records into an inhouse database for use in instructing students and for research into retrieval techniques, is now assumed to be cheap and easy by means of record transfer from CD‐ROM. During a recent operation of this kind a number of unforeseen problems were encountered, and the whole operation required 20 sub‐operations. But the task was quite successful, so it was decided to retrace the steps and measure carefully the time taken and computer storage requirements needed.

Reports a laboratory experiment in which verbalized tape‐recorded searches on five printed subject indexes reveal something of the linguistic processing that took place. Some 20% of the entries examined were changed grammatically, by word order change or function word supply, according to the linguistic form of the index concerned. Extracts from the search transcriptions are given, and the search processing modes of seeking, scanning, and screening are discussed.

An electronic alerting service which gathers both conventional and electronic documents and presents them to users still needs a vocabulary to match documents with profiles. Based on a project in the Electronic Libraries Programme known as NewsAgent; a personalised current awareness service for library and information staff, a design for a controlled vocabulary is described based on three levels of specificity: Channels, Topics and Keywords. The printed models for these vocabularies are identified, and examples given from the field of Library and Information Services. NewsAgent decided to adopt the Dublin Core metadata scheme in which to include this vocabulary, and details of both the simple and advanced use of this metadata by NewsAgent are discussed and illustrated, including the use of standard resource types which include an indication of quality. The publications which were used in the trial of NewsAgent are identified, and some future developments in electronic alerting outlined.

This approach to co‐operation between libraries and information centres considers the use of switching languages. These can be employed in situations where several centres with a common interest wish to co‐operate in the collection and indexing of information bearing material, yet prefer to retain the systems often developed and tailored to their individual requirements. To facilitate the exchange of subject information between the centres, a series of concordances are constructed between each of the indexing languages and the switching language. Thus the translation of subject indexing expressed in the indexing languages of the other participating centres can then proceed automatically. Among the possible benefits are the economic saving due to the sharing by several centres in the collection and indexing of material, and the increase in coverage enjoyed by all the centres. To determine the feasibility of such devices, a switching language, the Intermediate Lexicon for Information Science, has been developed and is under test at the Polytechnic of North London School of Librarianship. The work is supported by a grant from British Library Research and Development Department.

Aslib Library holds a collection of thesauri, subject headings and classification schemes which are used to answer members' enquiries about the existence of schemes for particular subject fields and many of which are available on loan for two weeks. Our policy is to acquire all significant English language publications and bilingual or multilingual items with English as one of the languages.