Causes of Boolean failures to retrieve relevant MEDLARS index references are: search formulator failed to include important terms, indexer failed to include important terms, and misunderstanding of user's needs. On the evidence of this test the Probabilistic search is at least a partial solution to these problems. (8 references) (Author/NH)

Compound words cause some difficulty in post-coordinate indexing systems: if too many are fractured, or the wrong categories are selected for fracturing noise will be produced at unacceptable levels on retrieval. (Author/MM)

Using 20 question-document pairs and the document corpus that had been searched to find them, a small-scale study was made of how effectively answer-providing documents can be retrieved by text searching. (MF)

Analyzes the nature of Boolean information retrieval in relation to the discrete weights of query terms, examines assigned weights from an approach involving thresholds, and generates an evaluation mechanism which allows the user to attach a threshold to the query term. Thirteen references are listed. (FM)

Explores the concept of cataloging, analyzes its functions and operations, and holds that as a control system bibliographic organization is subject to the laws of cybernetics. The role of relevance and the limitations of some regulatory devices are examined. (FM)

Presents five user experiments on incorporating behavioral information into the relevance feedback process in information retrieval, concentrating on ranking terms for query expansion and selecting new terms to add to the user's query. Topics include term ranking and user behavior; incorporating user behavior into term ranking; and user behavior…

Introduces two distribution schemes that partition documents over multiple processors and the corresponding multiprocessor retrieval algorithms that match relevant documents to user queries. The suggested framework is based on a general purpose hypercube multicomputer architecture with a dedicated disk for each node. A timing analysis for the…

Discusses user preferences for the representation, interpretation, and measurement of the relevance or usefulness of retrieved documents. Highlights include measurement of user judgments on documents; distance between rankings; measures of retrieval effectiveness; normalized performance measure; and the relationship of distance-based measures to…

Defines a fuzzy retrieval model as the basis for extending a weighted Boolean information retrieval system in which numeric query weights are replaced by linguistic descriptors that specify the degree of importance of the terms. A relevance classification process is described, and implementation and evaluation of the fuzzy retrieval model is…

Describes an approach that combines concepts from information retrieval, fuzzy set theory, and genetic programing to improve weighted Boolean query formulation via relevance feedback. Highlights include background on information retrieval systems; genetic algorithms; subproblem formulation; and preliminary results based on a testbed. (Contains 12…

Discussion of probabilistic information retrieval systems highlights the probability ranking principle and discusses when the standard retrieval policy is optimal. Topics discussed include calibration and refinement; independent assessment of relevance by the inquirer; certainty about the computed probabilities of relevance; and confidence and…

Discussion of document ranking methods to calculate the conceptual distance between a Boolean query and a document focuses on the Knowledge-Based Extension Boolean Model which evaluates weighted queries and documents effectively and avoids problems of previous methods. Semantic networks are discussed, and is-a hierarchies are explained. (21…

Examines the relationship between recall and precision in information retrieval performance and explains why a trade-off between them is unavoidable under certain conditions. Topics discussed include the theoretical behavior of precision and recall; mathematics of the recall curve; an example using a test document collection; and two-stage…

Demonstrates how recall and precision can be expressed using a topological approach to retrieval introduced by S.C. Cater (1986); investigates threshold and close match retrieval systems and optimal and non-optimal searching; and highlights relations with hypergeometric and non-standard distributions. Includes seven appendices of mathematical…