Presents a manually constructed knowledge representation aimed at increasing the effectiveness of information retrieval systems. The framework of first order theories is used to analyze the properties of this new structure. The analysis demonstrates that the retrieval function takes term dependencies into account and distinguishes between…

Explains a new methodology for thesaurus design that is specifically geared for use by novice end-users, and describes a faceted hierarchical thesaurus organization which provides an economical information retrieval system in a corporate setting. (Author/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)

Discusses expert systems and their value as components of information retrieval systems related to semantic inference, and describes IOTA, a model of an intelligent information retrieval system which emphasizes natural language query processing. Experimental results are discussed and current and future developments are highlighted. (Author/LRW)

Describes a model of an information retrieval system based on a thesaurus with weights. Appropriate terms are defined, and inclusiveness and two other fundamental properties of the system are presented. (CWM)

Describes a study that tested the effectiveness of a thesaurus as a search-aid in free text searching of a Finnish full text database. Linguistic and conceptual approaches are discussed; five search modes are explained; recall and precision are examined; and the use of proximity operators is discussed. (Contains 29 references.) (LRW)

Presents an algorithm for computation of discrimination values in automatic construction of dictionaries for information retrieval. (Author/PF)

Summarizes studies of pseudoclassification, a process of utilizing user relevance assessments of certain documents with respect to certain queries to build term classes designed to retrieve relevant documents. Conclusions are reached concerning the effectiveness and feasibility of constructing term classifications based on human relevance…

Describes a project that is developing an intelligent search intermediary to help users locate relevant passages in large full text databases. (The system automatically reformulates Boolean queries to improve search results and presents retrieved passages in decreasing order of estimated relevance.) The current status of the project and plans for…

The current state of information retrieval (IR) evaluation is reviewed with criticisms directed at the available test collections and the research and evaluation methodologies used, including precision and recall rates for online searches and laboratory tests not including real users. Automatic text retrieval systems are also discussed. (32…

The application of the theory of fuzzy sets to the description of information retrieval systems makes it possible (1) to take into account the fact that the degree of importance of the particular terms is of a continuous character, (2) to formalize the relations between terms describing documents and information requests (fuzzy thesaurus).…

Assesses the impact of current coverage and indexing policies on MEDLINE's retrieval performance in the medical behavioral sciences literature by comparing retrievals in EXCERPTA MEDICA, PSYCHINFO, SCISEARCH, and SOCIAL SCISEARCH. Searches were made with descriptors, cited references, and natural language, and recall, precision, and novelty ratios…

Describes technique for automatic book indexing requiring dictionary of terms with text strings that count as instances of term and text in form suitable for processing by text formatter. Results of experimental application to portion of book text are presented, including measures of precision and recall. Ten references are noted. (EJS)

A new method for concentrating keywords of a thesaurus, based on a mathematical study of the distribution of characters in a defined natural language. (Author/KP)

Examines early and current approaches to automatic thesaurus construction and describes an approach to automatic generation of global thesauri based on the term discrimination value model and on an appropriate clustering algorithm. Preliminary results of implementation of the method are reported. (46 references) (Author/MES)