Discusses the design of a model-based management information system in terms of mathematical/statistical, information processing, and human factors issues and presents a prototype system for interlibrary loan networks. (Author/CWM)

Describes class exercises where undergraduates construct and test mathematical models using data and issues related to social security. The students collect data and forecast economic and demographic variables that determine future tax rates. They then discuss government policies that are derived from their models. (MJP)

Describes the use of Mathcad, an interactive software package that responds to mathematical input, in an undergraduate economics class. Mathcad uses a rules-based programming language that "reads" the relationships among variables and constraints defined by the user, solves for unknowns, and graphs for one or more equations. (MJP)

Maintains that most economics textbooks continue to repeat past mistakes concerning returns to scale and economies of scale under assumptions of constant and nonconstant input prices. Provides an adaptation for a calculus-based intermediate microeconomics class that demonstrates the pointwise relationship between returns to scale and economies of…

A stochastic multidimensional unfolding (MDU) procedure is presented to represent individual differences in phased or sequential decision processes spatially. A Monte Carlo analysis demonstrates estimation proficiency and the appropriateness of the proposed model selection heuristic, and an application to capture awareness, consideration, and…

Describes five basic concepts, such as displacement, velocity, momentum, force, and moment of force. Discusses an experimental model to improve the intuitive understanding of acceleration in a straight line and a non-linear situation. (YP)

Discusses the global change of climate. Presents the trend of climate change with graphs. Describes mathematical climate models including expressions for the interacting components of the ocean-atmosphere system and equations representing the basic physical laws governing their behavior. Provides three possible responses on the change. (YP)

Presents a device to illustrate the concepts of entropy of mixing and the contribution of one term in the Gibb's equation. Notes the device is relatively easy to construct and provides a visual demonstration on diffusion. (MVL)

A pooled cross-section time series model is used to evaluate the effect of the 1977 Canadian firearms legislation on the provincial homicide rate between 1969 and 1989. Results agree with most studies that indicate no significant effect of this legislation on homicide rates. (SLD)

This review features new examples of using the computer relative to college-level mathematics to enhance pedagogy, solve problems, and model real-life situations. Included is a LOGO program that can be used to create and to stimulate subsequent investigations of spirolaterals, those figures generated by repeatedly drawing basic loops. (JJK)

Presents the origin and mathematics of Hubble's Law of the expanding universe. Discusses limitations to this law and the related concepts of standard candles, elliptical galaxies, and streaming motions, which are conspicuous deviations from the law. The third of three models proposed as explanations for streaming motions is designated: The Great…

Presents a simple mathematical model in which resultant speed is the sum or difference between wind speed and runner speed and a more complex model that assumes that only a proportion of the wind's speed affects one's running speed to describe the time difference between running with and without wind. (MDH)

A mathematical model is proposed to describe how group differences in distributions of abilities, which are distinct from the target ability, influence the probability of a correct item response. In the multidimensional approach, differential item functioning is considered a function of the educational histories of the examinees. (SLD)

Using longitudinal data on career paths of 3,941 special educators, maximum likelihood estimators are derived for the parameters of a discrete-time hazard model, and it is shown that the model can be fit using standard logistic regression software. Illustrative computer codes from the Statistical Analysis System (SAS) are offered. (SLD)

Describes a study that used transaction log analysis to investigate the use of subject searching in the University of California's Online Union Catalog, MELVYL. Mathematical models of trends and patterns in the data are presented, problems with subject searching are explained, and remedies to subject searching problems are suggested. (62…