Optimal setpoint control of complex heat exchanger systems

This paper presents an approach for calculating the best way of distributing the streams following through a certain class of complex heat exchanger systems in order to achieve maximum heat recovery within the system. A computer code has been developed by which the described method is demonstrated, off-line, for two real cases. This program can be readily integrated into an over-all, on-line computer control system for any complex process consisting of an exchanger system of this class. Using an accurate and detailed heat exchanger model, the exit temperatures of each exchanger are calculated by a simple mathematical procedure based on Gilmour's design method. This procedure has been included in a general model for the complete scheme of the system. The scheme is made up of a series of heat exchanger groups with parallel paths in each group. The optimal distribution of the streams within a group is found by the direct search method of Hooke and Jeeves, modified to include constraints; while the overall optimization of the system is achieved via dynamic programming.     

Technologizing Africa: On the bumpy information highway

Although the microcomputer and the Internet continue to advance rapidly in Western cultures, developing nations, especially those in Africa, are lagging behind—a situation that continues to widen the gap between the haves and the have-nots of the world. This article offers the rare opportunity to get a glimpse of Africa on the information highway and documents the use of computers in the educational systems of three African nations: Ghana, Kenya, and Egypt. It documents the progress these countries have made in exposing their citizens to information technology and reveals the challenges they face in closing the digital divide that Africans continue to experience. In presenting how these countries adapt to technological change, one may better understand why Africa's ride on the information highway is rutted.     

Analysing fun as a candidate software requirement

Analysis of concepts related to fun is used to suggest the main areas where fun may be important to software design. The issue is important as many analyses and design methods fail to allow for designs aimed at user enjoyment, even though computer games are now a major industry. The main cases seem to be either where enjoyment is the chief aim (requirement) of the design, or where learning is important. The phenomena of flow experiences are also important here, and raise the issue of designing for desirable cognitive modes of interaction, as well as for desired end results. However the relationship of learning and fun, while clearly important, is complicated.     

Dialoguing with developers and suppliers of adaptive computer technologies: Data and recommendations

The authors report on findings on computer technology needs and concerns of 725 Canadian college and university students with a wide range of disabilities. The vast majority of this sample population uses computers and almost half need an adaptation to use computers effectively. The authors provide information about computer technologies used by students with different disabilities, describe adaptations/adaptive computer technologies that students find useful, report issues faced by users and non-users of computers in postsecondary education, and discuss reasons why students are not using needed adaptations/adaptive technology. Based on these findings, the authors provide recommendations for adaptive computer hardware and software developers and vendors. Published online: 21 March 2002     

A mini imitation game: How individuals model social robots via behavioral outcomes and social roles

In past works, social robots have been designed to mimic human appearances and behavior. However, little is known about how human beings may imitate social robots. Drawing on social cognitive theory and the Media Equation, this study focuses on the modeling effects of social robots in an environment protection context. A lab experiment (N = 128) with a between-subjects factorial design was conducted to examine how social robots’ behavioral outcomes and social roles affected individuals’ modeling behavior. This study suggested that social robots’ positive behavioral outcomes were effective in evoking users’ modeling tendencies serially through social presence and identification or only through identification. Robots’ mere presentation of behavior with no outcomes exerted effects serially through social presence and identification. Additionally, assigning social robots an instructor role led to users’ modeling behavior serially through users’ perception of robots’ expertise and credibility. The study analyzed the psychological mechanisms behind users’ modeling behavior.