How does one develop a fair distribution of equitable work loads for faculty involved in operating a cooperative education program? Attempts to specify the responsibilities required, estimate the amount of time needed to meet these responsibilities, and equate this time with the time required for meeting normal classroom requirements. (Author/RK)

A simulation experiment for the dissolution kinetics of steroids is described whose goals are to demonstrate the characteristics of the physical-chemical model for dissolution and to relate the physical-chemical model to the potential therapeutic availability of the drug. Computational details are given. (LBH)

Several examples of concrete mathematical models are discussed along with suggested criteria for good heuristic models. (MN)

This article examines the Pythagorean Theorem from a geometric point of view by suggesting some natural extensions of the theorem. The use of a more general theorem to prove a difficult one is suggested, where possible. The article includes figures and proofs. (Author/MA)

Presents a simple model whereby the work per cycle done on an external agent, and a sand reservoir, by a reversible heat engine can be analyzed explicitly. (Author/SL)

Analyzes the sudden drop in the isothermal entropy of mixing when two ideal quantum gases are made identical. (Author/SL)

Introduces the concept of mutual inertia, analogous to mutual inductance, through the study of oscillations in a periodic linear chain of particles, on an air-track, joined by loaded strings. (SL)

Demonstrates that a particle traveling in a helical path provides a mechanical model describing the quantum-mechanical wave function formalism. (SL)

This is the fourth and concluding article in a series on using mathematical techniques from history to provide an interesting way for middle graders to practice math. (Editor)

This paper considers one system of careers, Wisconsin school superintendents from 1940 through 1972, and examines the extent to which statistical characteristics of that system are consistent with a simple Markov model that assumes both individuals and jobs to be indistinguishable and careers at that level to be essentially random. (Author)

Timing stoplights and trying to determine the best way to allocate cycle time to the two directions is discussed. The simple case and improving the model are both considered. (MNS)

Psychometricians working in factor analysis and econometricians working in regression with measurement error in all variables are both interested in the rank of dispersion matrices under variation of diagonal elements. This paper reviews both fields; points out various small errors; and presents a methodological comparision of factor analysis and…

This paper develops and applies three nonparametric comparisons of the shapes of two item characteristic surfaces: (1) proportional latent odds; (2) uniform relative difficulty; and (3) item sensitivity. A method is presented for comparing the relative shapes of two item characteristic curves in two examinee populations who were administered an…

This paper describes a PASCAL program that computes both different types of transitions and learning statistics suitable for learning experiments in which a two-stage Markov model is used. The frequency counts of the different transitions are used for estimating the parameters of the two-stage Markov model. (Author/LMO)

Two articles describe a model for processing natural-language queries in information retrieval systems. Part I proposes a language interface based on fuzzy set techniques to handle the uncertainty inherent in natural-language semantics. Part II develops a model of the retrieval system and describes an implementation using a knowledge-based systems…