D. E. Stevenson

A critical look at quality in large-scale simulations

There is a disconnect between ASCI science and management. The author proposes an alternative paradigm. Simulation quality depends on the quality of insights gained, but software engineering is not the discipline to develop those insights. The author also proposes a definition for validation and differentiates it from current internal quality and verification approaches.

Empirical evidence for the existence and uses of metacognition in computer science problem solving

We describe the second phase of an ongoing study whose aims are to explore how computer science students solve problems and to understand the relationship between metacognition and schemata. This research uses verbal protocols from computer science students, and based on the analysis of their transcripts, empirical evidence supports metacognition as a significant role in computer science problem solving. For the problem solved in this research, the students reveal a pattern in their interactions between metacognitive processes and the domain-specific strategies used to develop a program.

Intestinal alkaline phosphatase activity in relation to age in humans

Early studies of a few subjects suggested that intestinal alkaline phosphatase (IAP) activities in children 5 years of age or less were higher than in older individuals. To further investigate this finding, the IAP and disaccharidase activities of 298 subjects (133 were 5 years of age or less) with normal intestinal histology were assayed. Ninety-five of the children had serum alkaline phosphatase determined. The youngest individual with a low lactase activity was 5 years of age, which supported the earlier findings. When the whole population was tested, there was no correlation between the intestinal and serum alkaline phosphatase values. The mean IAP activity of subjects 1 year old and less was greater than in older individuals, but there was greater statistical dispersion and the data were not normally distributed. When studying the natural logarithm of the data, a wide dispersion of values about the mean in the 0 to 3 year-old age group was observed. This qualitative behavior is characteristic of functions involving the base of the natural logarithm and of processes that “age” in a simple way.

Using Bloom's taxonomy to code verbal protocols of students solving a data structure problem

We describe a preliminary study exploring how computer science students solve a problem in an attempt to understand differences between the successful and the unsuccessful problem solver. Students followed a verbal protocol as they solved a data structures problem, and we analyzed the transcripts of these problem-solving sessions, classifying the statements students made using the revised Blooms taxonomy. Based on our analysis in this case study, we conclude that the successful problem solver seems to move more frequently from one type of cognitive process to another than the unsuccessful problem solver. For the particular data structure problem the students attempted to solve, we observed that all problem solvers, successful or unsuccessful, tend to follow patterns in their problem-solving process.

The Michelson-Morley experiment: a case study on validation

The Michelson-Morley experiment can be examined, using standard mathematical concepts of error analysis, as a case study in validation. A few philosophical principles focusing on scientific confirmation help elucidate the formal logical concepts that result in a foundation for scientific validation. The author proposes two research directions.

Frontiers for computer science in computational science

Computational Science (<i>CPLSC</i>) is an emerging discipline characterized by interdisciplinary team efforts and high precision computing. Computer science is just one dimension of this new discipline.We describe the Clemson program focusing on three major issues: <i>(i)</i> what are the foundations of <i>CPLSC</i>, <i>(ii)</i> how are we to educate computer science students in <i>CPLSC</i>, and <i>(iii)</i> what role does computer science play in <i>CPLSC</i> research?

Performance of Mutual Exclusion Algorithms on Hypercubes

Three popular algorithms commonly used for providing mutual exclusion in non-shared in e na o ry in od e Is a re des crihe d. Imp le mentation of these algorithms on Intel iPSC/2 suggests that selection of mutex algorithm should be based on ease of inaplenzentaiion aid ease of extension rath.er than merely on, the number of messages exchanged dirring execution.

BIOBELL — A simulation system for biochemistry and biophysics

The BIOBELL simulation system is designed to simulate biochemical kinetics and nuclear magnetic resonance phenomena. The system uses portable software from the PORT Library and GASP system. The user language is illustrated. The implementation of the portable compiler - compiler and portable stiff ordinary differential equation solver are discussed. Guidelines for similar projects are given.

Exploring an information-based approach to computation and computational complexity

We present the background and justification for a new approach to studying computation and computational complexity. We focus on categories of problems and categories of solutions which provide the logical definition on which to base an algorithm. Computational capability is introduced via a formalization of computation termed a model of computation. The concept of algorithm is formalized using the methods of Traub, Wasilkowski and Woźniakowski, from which we can formalize the differences between deterministic, non-deterministic, and heuristic algorithms. Finally, we introduce our measure of complexity: the Hartley entropy measure. We provide many examples to amplify the concepts introduced.

Introducing Computational Science Methods Using Parallax

We briefly describe the Clemson computational science and engineering course. We describe a parallax case study for studying floating-point computation. We outline our presentation of error analysis and a slight abstraction of IEEE arithmetic that we call Wilkinson arithmetic. The students are asked to determine how far parallax is usable given the parameters of the model. We provide one analysis of the problem and topical ideas for students.