Database Producers Research Articles

Measuring overlap of data bases in water supply and sanitation using sampling and the binomial probability distribution

A quick and easy method is presented to estimate the overlap of data bases, which can be used to assist the data base producers and managers in their policy towards coverage of their subject area. The method has been applied to bibliographic data bases on low-cost water supply and sanitation, yielding information for users and for the data base producers.

Sign detection theory and its applications

A characterisation of sign-transmission is offered which is more general than conventional signal-transmission theory. Whereas the latter relies on continuous random variables mapping from two sets of objects (the signalling set and the noise set) to portray receiver performance, sign-detection theory does so using pairs of discrete probabilities attached to elementary logical conjuncts of query terms, these conjuncts partitioning the two sets of objects. Further mappings are more general than those that map to the real numbers. The modified formalism recognises a transmitter, an intermediary, and a percipient, and a “metasignal” is defined to explain information-seeking behaviour by the percipient. This approach allows the effect of choosing all possible logical search expressions to be portrayed, for example as a bivariate distribution of these expressions over the Recall-Precision outcome space, as Recall and Precision distributions marginal to the latter, or as a distribution of a metric measuring distance between the “signed set” and the “perceived as signed” set. Sets of “successful”, i.e. more-effective, search expressions are defined by choosing intervals of Precision, Recall, etc. outcome-spaces to which such expressions map. The problem of modelling such distributions differs from that of modelling the random variables of conventional signal-detection theory. Empirical data on instances of medical information communicated through the MEDLINE data base are described for abstractly-defined percipients. A prototype psychological experiment in the area of cognitive perception is also described, in which a percipient is required to identify, using public record attributes, an attribute used privately by a transmitter. This process differs from conventional experiments in perception that describe sensory perception only and which are expressed in the language of signal-detection theory. The diffusion of signed objects through a (changing) data base with time can be simply incorporated in the theory as variation in signal-to-noise ratio, and on this basis a conjecture is offered as to sign-creation by data base producers.

Indexing consistency, quality and efficiency

Indexing quality determines whether the information content of an indexed document is accurately represented. Indexing effectiveness measures whether an indexed document is correctly retrieved every time it is relevant to a query. Measurement of these criteria is cumbersome and costly; data base producers therefore prefer inter-indexer consistency as a measure of indexing quality or effectiveness. The present article assesses the validity of this substitution in various environments.

Data Base Directories: A Comparative Review

Over the past decade machine‐readable data bases have grown both in number and variety. In addition to the familiar bibliographic data bases such as MEDLINE and ERIC, one now finds data bases containing such things as properties (e.g., RTECS ‐ Registry of Toxic Effects of Chemical Substances) and full text (e.g., LEXIS, a family of files that contains the full text of court decisions, statutes, regulations, and other legal materials). As data bases increase in importance as information resources, there is a growing need for printed tools which can assist librarians in their identification and use. Available tools fall into three categories: (1) guides issued by data base producers which describe the contents of a given data base and methods of searching (e.g., INSPEC Database Users' Guide); (2) guides produced by online vendors which indicate how data bases can be searched on a particular system (e.g., Lockheed's Guide to DIALOG ‐ Databases); and (3) data base directories which include coverage of data bases produced by many different organizations and processed by a variety of online vendors. The third category is the subject of this comparative review. Readers interested in the first two categories should consult Online Reference Aids: A Directory of Manuals, Guides, and Thesauri published by the California Library Authority for Systems and Services (CLASS). This publication contains information on manuals, guides, and other search aids for over 100 online data bases, including those available through the New York Times Information Bank, National Library of Medicine (NLM), Bibliographic Retrieval Services (BRS), Lockheed DIALOG, and System Development Corporation (SDC) ORBIT. This directory is arranged by data base name, giving ordering and price information for aids available from both data base producers and online vendors. Subject and vendor indexes are also provided.

On‐line update

On‐line update combines a bibliography of recent on‐line articles with a search example from a data base producer or an on‐line system vendor.

News

Dow Jones Announces News/Retrieval Service; Now Sees Itself as “Retailer” of Information. When a data base producer decides it is time to enter the on‐line era, it most frequently choses to do so by forming a “partnership” with one or more of the existing on‐line vendors‐companies such as SDC, Lockheed, or BRS‐which have existing computer facilities as well as marketing and educational programs.

User education and training

A number of data base producers are offering or developing training schemes designed to help on‐line users acquaint themselves with the construction of their data bases. In this issue we describe the philosophy and content of training courses offered by BIOSIS and INSPEC.

On‐line update

On‐line update combines a bibliography of recent on‐line articles with a search example from a data base producer showing techniques especially useful in searching its data base. In this issue, we have asked the Institute for Scientific Information (ISI) to provide a bibliography of literature concerning on‐line retrieval. Only articles which have been added to their file since June 1976 are included. In the next issue of On‐Line Review, INSPEC will do a search on the same subject, which should provide our readers with an interesting comparison.

The impact of machine-readable data bases on library and information services

Library and information services already feel the impact of the burgeoning development in the field of bibliographic data bases, and this effect will increase in the future. This article explores the growth, origins, technological development, and current activities of bibliographic data bases and examines the NCLIS National Program relative to these aspects. The relationships between data base function, funding, and use are set forth in a discussion of data base producers. Discussions of data formats, data elements and file structure provide the groundwork for a closer look at the methods and purposes underlying the retrospective and current awareness search capabilities of existent data bases. A review of related data base and data base center characteristics highlights the discussion of retrospective and current awareness search functions and intermediary search services. In all data base activity the prime objective of making available information easily accessible to all who need it emerges as no small task, especially in light of the realities of scattered resources and unsteady funding. Data base networking and resource sharing constitute one means to the achievement of this ideal. The greatest potential of the NCLIS National Program lies in this direction, in its ability to promote and provide a framework for the coordination of data base-related activities and research in response to national needs.

Abstracting and indexing services as data base producers: economic, technological and co‐operative opportunities

I think this conference is an extremely timely one and an extremely important one. I think that to a great extent the importance of the industrial information centres, for instance those belonging to research associations have not been considered as an important national asset. All the research associations over a period of many years have developed their information services, abstracting‐and communication services to such an extent that they are now important data sinks for their industrial segments. In fact research associations have developed, not only in the classical abstracts for the chemists and physicists, the traditional scientist, but also now for economics, marketing and industrial information of all sorts, health and safety regulations and EEC regulations. All this sort of data is now an important aspect of their information networks. There are 43 research associations in Great Britain and they have data sinks which, in my opinion, are underrated and underutilized except by their own membership, and I think the future of those bases should be a subject for considerable study, both by the British Government, the British Library and the other organizations concerned. I believe we have something unique here in this country which I would like to see collected together and exploited in the fullest sense. It must always be quite clear that unless we do take this sort of action we can sec ourselves losing out to the very heavily subsidized organizations e.g. France and Germany.

Lockheed experience in processing large data bases for its commercial information retrieval service.

The last few years have seen the emergence of the information retrieval services industry. This industry consists of three tiers: data base producers, retrieval service vendors, and information centers who service the end user. The experience of Lockheed Information Systems as a retrieval service vendor is recounted as it pertains to its system and to its relationship with the data base suppliers. Government competition is seen as a potential threat to the industry.

COMPARATIVE EFFICIENCY OF SEARCHING TITLES, ABSTRACTS, AND INDEX TERMS IN A FREE‐TEXT DATA BASE

The choice of a suitable data base for providing an information service is governed by factors of coverage, performance, and cost. The cost of the data base to subscribers is a known quantity, and the coverage is decided by the data base producers. This paper describes an investigation into the relative performance of the four major Chemical Abstracts Service magnetic tape data‐bases, Chemical Titles (CT), which contains the titles of citations only, Chemical Abstracts Condensates (CAC), which contains titles enriched with keyword phrases, Chemical‐Biological Activities (CBAC), and Polymer Science and Technology (POST), both of which contain full digests in addition to titles. The performance was measured in terms of the relative currency of the four data‐bases, and the retrieval efficiency of profiles searched against them. Fifty questions from industrial and government research organizations were used in the experiment. Search profiles corresponding to these questions were constructed for searching against each data‐base, output was assessed for relevance by users, and profile performance figures (precision and recall ratios) were calculated for each profile. The overall retrieval efficiency of profiles searched against data‐bases containing titles only, titles‐plus‐keywords, and titles‐plus‐digests, was calculated, and these results are presented.