The suggestion that the IDIOSCAL model be fitted by the TUCKALS2 algorithm for three-way components analysis is examined. The claim that resulting coordinate matrices will be identical is supported when the data matrices are semidefinite. Counterexamples for indefinite matrices are also constructed. (SLD)

Describes a study funded by the Commission of the European Community that applied document retrieval algorithms to the "Excerpta Medica" database using the EMTREE thesaurus. Nonhierarchical relations were added to enrich the thesaurus, and document ranking is discussed in terms of the conceptual distance between the documents and the…

Proposes a model of knowledge-based information retrieval (KBIR) that is based on a hierarchical concept graph (HCG) which shows relationships between index terms and constitutes a hierarchical thesaurus as a knowledge base. Conceptual distance between a query and an object is discussed and the use of Boolean operators is described. (25…

A method of automatically selecting items for inclusion in a test with constraints on item content and statistical properties was applied to real data. Tests constructed manually from the same data and constraints were compared to tests constructed automatically. Results show areas in which automated assembly can improve test construction. (SLD)

Differences in students' (aged 12-14) construction and analysis of mathematical algorithms may be explained by the differences between predicative and functional cognitive structures. Analyzes the central role of internal and external representations and the characteristics of each. Discusses prototypical research design and development of a…

The ability of the NORMIX algorithm to recover overlapping population structures was compared to the OVERCLUS procedure and another clustering procedure in a Monte Carlo study. NORMIX is found to be more accurate than other procedures in recovering overlapping population structure when appropriate implementation options are specified. (SLD)

Database Tomography (DT) is a system which includes algorithms for extracting multi-word phrase frequencies and performing phrase proximity analyses on any type of large textual database. DT was used to derive technical intelligence from a near-earth space (NES) database derived from the Science Citation Index and the Engineering Compendex.…

Applies neural network methods for forecasting 1991-95 per-pupil expenditures in U.S. public elementary and secondary schools. Forecasting models included the National Center for Education Statistics' multivariate regression model and three neural architectures. Regarding prediction accuracy, neural network results were comparable or superior to…

Presents a student module modeling knowledge states and learning skills of students in the field of Newtonian dynamics. Uses data recorded during the exploratory activity in microworlds to infer mental representations concerning the concept of force. A fuzzy algorithm able to follow the cognitive states the student goes through in solving a task…

Evaluates the effectiveness of spelling-correction and string-similarity matching methods in retrieving similar words in a Malay dictionary associated with a set of query words. Describes experiments that showed the best search combination used a stemming algorithm, and calculates retrieval effectiveness and relevant means measures from weighted…

Compares traditional mathematical models with computer simulations. Shows the strengths and flexibility of algorithmic computational simulations through a program designed to investigate and extend understanding in one of the most enduring questions in social choice research. Discusses solutions to this problem from each approach--analytic and…

In information retrieval (IR), the aim of genetic algorithms (GA) is to help a system to find, in a huge documents collection, a good reply to a query expressed by the user. Analysis of phenomena seen during the implementation of a GA for IR has led to a new crossover operation, which is introduced and compared to other learning methods.…

A statistical power algorithm based on the Fisher Z method is developed for cutoff-based random clinical trials and the single cutoff-point (regression-discontinuity) design that has no randomization. This article quantifies power and sample size estimates for various levels of power and cutoff-based assignment. (Author/SLD)

Reports on a study, Project REMODEL, that implemented and evaluated innovations in lecture, laboratory, and assessment for students in the introductory sequence for undergraduate chemistry. Results indicate that special sessions and conceptual exam questions can improve students' abilities to work successfully with both concepts and algorithms.…

The equivalence of pencil and paper Rasch item calibrations when used in a computer adaptive test administration was explored in this study. Items (n=726) were precalibarted with the pencil and paper test administrations. A computer adaptive test was administered to 321 medical technology students using the pencil and paper precalibrations in the…