Discusses term position as a search tactic in Boolean retrieval systems and describes ranked output systems that have used term weighting. The use of term proximity devices in ranked output systems is proposed, the algorithms used are explained, and a search experiment with a test collection is described. (19 references) (LRW)

Investigates document ranking methods in thesaurus-based Boolean information retrieval systems and proposes a new thesaurus-based ranking algorithm called the Extended Relevance algorithm. Performance comparisons are made between the Extended Relevance algorithm and previous thesaurus-based ranking algorithms. (Contains 20 references.) (LRW)

Describes the advantages of a prototype retrieval system that uses statistically based ranked retrieval of records rather than traditional boolean methods, especially for end users. Several new techniques are also discussed including bit mapping, pruning, methods of building inverted files, and types of search engine. (26 references) (EAM)

Discusses the interpretation of nominal compounds in the context of natural language processing for information retrieval. Knowledge-intensive algorithms that can successfully interpret compounds found in technical documents are described, and experiments are reported that indicate these algorithms may be unnecessary for improving retrieval…

Discussion of the problem of control in documentary information retrieval (IR) systems focuses on feedback mechanisms. Information needs are discussed, particularly the Problem Oriented Information Need (POIN); the structure of an adaptive IR system is described; and the design of algorithms for automated IR systems is explained. (33 references)…