An investigation was made into the relative performance of the four major Chemical Abstracts Service magnetic tape data-bases. 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. (5 references) (Author/NH)

An n-gram is a string of characters, usually adjacent, extracted from a section of continuous text that can be used in spelling error detection and correction, query expansion, information retrieval, dictionary search, text compression, and language identification applications. This article provides an introduction to the use of n-grams in textual…

Surveys the literature of the field. Includes a 152-item bibliography. (PF)

Indexing is the preprocessing of information to enable its retrieval, ranging from classification-based (precoordinate) to keyword searching (postcoordinate) approaches. This article describes a framework for modelling information retrieval systems in terms of sets of objects, relationships, and functions and discusses the application of indexing…

Discusses the design of interfaces for online systems and suggests requirements that must be met to offer maximum aid to inexperienced users. Highlights include the online search process, user data, query processing, database descriptors, semantic links, multilingual processing, search strategies, and distributed systems. A 20-page bibliography…