My personal history in the early explorations of computer graphics

Gary Demos discovered computer graphics while hearing a computer-generated film presentation at CalTech in 1970 by John Whitney Sr. Gary then began working under the direction of Ivan Sutherland in Utah to develop early computer graphics hardware and software. In 1974 Gary and John Whitney Jr. started the “Motion Picture Project” at Information International to produce computer generated simulated scenes for movies (Futureworld, Looker, and Tron) and commercials. These early computer-generated visuals were quite challenging given the level of software and hardware technology available in the 1970’s. In 1981 Gary and John left Information International to form Digital Productions, where they produced effects for the movies Last Starfighter and “2010”, which were both released in 1984. Digital Productions used the Cray XMP computer, together with the Digital Film Printer that they had developed at Information International. Following a hostile takeover by Omibus of Digital Productions in 1986, Whitney/Demos Productions was formed, using a Thinking Machine parallel computer. This paper describes the technical challenges and achievements of this early visual computing.     

Genetic subsets regression

Subset regression procedures have been shown to provide better overall performance than stepwise regression procedures. However, due to the combinatorial nature of evaluating each potential subset, subset regression techniques are costly to use. To resolve this difficulty, the use of a simple genetic algorithm (GA) is proposed to reduce the number of subsets which must be evaluated. Any of a number of popular criteria, including Mallows' C_p, MSE, R², AIC, etc., can be used to drive the search strategy associated with the use of the GA. Several illustrated examples on its use are provided.     

A multi-institutional, multinational study of programming concepts using card sort data

Abstract: This paper presents a case study of the use of a repeated single‐criterion card sort with an unusually large, diverse participant group. The study, whose goal was to elicit novice programmers' knowledge of programming concepts, involved over 20 researchers from four continents and 276 participants drawn from 20 different institutions. In this paper we present the design of the study and the unexpected result that there were few discernible systematic differences in the population. The study was one of the activities of the National Science Foundation funded Bootstrapping Research in Computer Science Education project (2003).     

An Adaptable Oscillator-Based Controller for Autonomous Robots

This paper proposes a unique oscillator-based robot controller with learning abilities to effectively guide a team of robots operating in uncertain environments. To verify this, we designed four separate controllers and compared their performance in a series of tests in several different environments. The experiments used a team of three robots to explore arenas with variable lighting and different obstacle patterns, with a goal of having the team as a whole absorb as much light as possible. The four controllers were: a reactive controller, an oscillator with fixed parameters, an oscillator whose parameters changed based on the pattern of sensor information received, and an oscillator-based controller that used reinforcement learning. Experiments confirmed that the proposed method outperforms the others in all environments tested. This material is based upon work supported in part by the U.S. Army Research Office under grant/contract number DAAG55-98-1-0011.     

Supporting Scientific Collaboration: Methods, Tools and Concepts

This paper discusses the interrelationship between e-Science and CSCW in terms of key substantive, methodological and conceptual innovations made in both fields. In so doing, we hope to draw out the existing relationship between CSCW and e-Science research, and to map out some key future challenges where the two areas of research may become more closely aligned. In considering what may be required to draw the two more closely together, the paper focuses primarily on investigations that have been undertaken in two dedicated initiatives into e-Science, along with the key issues emerging from these studies.     

Enterprise Performance Management: Making it Work

Abstract

Enterprise performance management (EPM) is the integration of control and improvement methods imbedded with analytics. Its methods include the strategy map, balanced scorecards, costing (including activity based cost management), budgeting, forecasting and resource capacity requirements planning. These methods fuel other core solutions such as customer relationship management (CRM), supply chain management (SCM), risk management, and human capital management systems, as well as lean management and Six Sigma initiatives.     

THE RELATIONSHIP OF CONTROL AND LEARNING TO PROJECT PERFORMANCE

ABSTRACT

Management controls can be divided into two types that can have opposite effects on organizational learning: behavioral controls, which promote efficiency but also stifle much of the learning opportunity, and outcome controls, which foster interaction among stakeholders can add to the learning environment. This article reports on a study that confirms these observations and explores the nature of their direct and indirect influences on project performance. Data from a sample of software development professionals confirms that behavioral controls and learning directly influence project performance, while outcome controls contribute only indirectly through their impact on learning.     

Testing the robustness of the dysphoria factor of the Simms et al. (2002) model of posttraumatic stress disorder.

The Simms et al. (2002) four-factor structure of posttraumatic stress disorder (PTSD) has been supported in many factor analytic studies, and the specificity of the dysphoria factor has been questioned because of its strong associations with measures of depression and anxiety. This study addressed this issue by conducting a confirmatory factor analysis while controlling for the symptoms of major depression (MD) and generalized anxiety disorder (GAD). Data from individuals who satisfied Criterion A of the diagnostic criteria for a Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM–IV) diagnosis of PTSD (n = 12,467) in the 2004–2005 National Epidemiologic Study on Alcohol and Related Conditions (NESARC) were used in the analysis. The results showed that after controlling for MD and GAD, the factor loadings for dysphoria items were significantly attenuated, although they remained relatively high and statistically significant. The present findings contribute to the debate regarding how PTSD should be conceptualized and assessed in future issues of the DSM. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Strength variability of single flax fibres

Due to the typical large variability in the measured mechanical properties of flax fibres, they are often employed only in low grade composite applications. The present study aims to investigate the reasons for the variability in tensile properties of flax fibres. It is found that an inaccuracy in the determination of the cross-sectional area of the fibres is one major reason for the variability in properties. By applying a typical circular fibre area assumption, a considerable error is introduced into the calculated mechanical properties. Experimental data, together with a simple analytical model, are presented to show that the error is increased when the aspect ratio of the fibre cross-sectional shape is increased. A variability in properties due to the flax fibres themselves is found to originate from the distribution of defects along the fibres. Two distinctive types of stress–strain behaviours (linear and nonlinear) of the fibres are found to be correlated with the amount of defects. The linear stress–strain curves tend to show a higher tensile strength, a higher Young’s modulus, and a lower strain to failure than the nonlinear curves. Finally, the fibres are found to fracture by a complex microscale failure mechanism. Large fracture zones are governed by both surface and internal defects; and these cause cracks to propagate in the transverse and longitudinal directions.