Describes two similarity measures used in citation and co-citation analysis--the Jaccard index and Salton's cosine formula--and investigates the relationship between the two measures. It is shown that Salton's formula yields a numerical value that is twice Jaccard's index in most cases, and an explanation is offered. (13 references) (CLB)

Describes a string-searching algorithm for multiple patterns in a text string; explains the construction of a pattern-matching machine; presents a theoretical analysis and empirical evidence that supports the sublinearity of the algorithm; and compares this algorithm with the Boyer-Moore algorithm for a single pattern. (Contains 10 references.)…

Sixty-one students provided the Library of Congress (LC) subject terms they would use to search an academic library catalog in 30 hypothetical searches. Students had difficulty developing strategies. The study concluded that LC subject cataloging needs rationalization. (KP)

Presents three text compression methods of increasing power and evaluates each based on the trade-off between compression gain and processing time. The advantages of using hash coding for speed and optimal arithmetic coding to successor information for compression gain are discussed. (26 references) (Author/CLB)

A comparative evaluation of results in terms of recall and precision from queries submitted to systems with automatic and manual subject indexing. Differences were attributed to query formulation. The effectiveness of automatic indexing was found equivalent to manual indexing. (Author/KP)

Reports on a controlled experiment that compared cloze procedure (human tendency to complete a familiar but not quite finished pattern) and comprehension quiz as measures of computer program understanding. Program comprehension measures, experimental materials, administration, and results are highlighted. Twenty-six references and sample questions…

Reports a study that examined 10 collections of mainly scientific subject areas indexed using Farradane's system of relational indexing. It compared (1) the use of relations, (2) the use of concept types, (3) the cross sections (or shape) of abstracts, and (4) the properties of "nodes." Statistical tables and graphs are included.…

Presents two partitioning methods for signature files and a method of fast weight computation to implement a document ranking strategy. Storage requirements, number of disk accesses, and processing time for these methods are compared with two other access methods. Merits of the partitioning methods are summarized. (20 references) (MES)

Identifies four components of a good predictive lossless image compression method: (1) pixel sequence, (2) image modeling and prediction, (3) error modeling, and (4) error coding. Highlights include Laplace distribution and a comparison of the multilevel progressive method for image coding with the prediction by partial precision matching method.…

Outlines the concepts and facilities of SLC-II, a basic support for R&D in automatic documentation and language translation, and gives a detailed description of its use in automatic indexing. The design and running of a full-scale pilot project is described, with a parallel experiment in the effectiveness of "thesaurus enrichment" by semiautomatic…

Results of study examining identification of important literature in quantum mechanics using gamma test of association on two literature sets indicates that use of citation analysis alone or historical analysis alone will not result in same set of literature being produced. List of historical sources and 19 references are appended. (EJS)

Discusses properties of multiple attribute tree (MAT) and inverted file structures; establishes suitability of MAT data structure for bibliographic files using worst-case performance measures; provides arguments to establish MAT average case superiority; and proposes an efficient adaptation of MAT data structure to exploit special features of MAT…

Compares the performance of inverted and signature file organizations in handling incrementally specified Boolean queries to an information retrieval system. The discussion covers the impact of more sophisticated signature file organizations, related problems, and possible future work. (65 references) (CLB)

Presents new methods for compressing bit matrices in large information retrieval systems which exploit possible correlations between rows of words and columns of documents. Three encoding methods are tested and compared--Shannon-Fano, arithmetic, and Huffman--and an appendix discusses binomial coefficients. (20 references) (LRW)

Presents model of algorithm design (activity in software development) based on analysis of protocols of two subjects designing three convex hull algorithms. Automation methods, methods for studying algorithm design, role of discovery in problem solving, and comparison of different designs of case study according to model are highlighted.…