Site preference of refractory elements in γ′-Ni3Al alloyed with Ru

The influence of ruthenium (Ru) on the partitioning behavior of W, Re and Cr in γ′-Ni₃Al has been studied using the Dmol3 method based on the density functional theory. The calculated results show that W, Re and Cr have a preference for the Ni site in γ′-Ni₃Al alloyed with Ru. When Ru substitutes the central Ni atom, the site preference for W, Re and Cr varies. Furthermore, an electronic structure analysis of the alloy in terms of the Mulliken population and partial density of states was performed to elucidate the alloying mechanism of Ru in γ′-Ni₃Al. The results show that the strengthening effect of Ru in the alloy arises from a reduction in the binding energy of Ru as well as p-orbital hybridization between Ru and the host atoms.     

Open Problems in the Philosophy of Information

Abstract: The philosophy of information (PI) is a new area of research with its own field of investigation and methodology. This article, based on the Herbert A. Simon Lecture of Computing and Philosophy I gave at Carnegie Mellon University in 2001, analyses the eighteen principal open problems in PI. Section 1 introduces the analysis by outlining Herbert Simon's approach to PI. Section 2 discusses some methodological considerations about what counts as a good philosophical problem. The discussion centers on Hilbert's famous analysis of the central problems in mathematics. The rest of the article is devoted to the eighteen problems. These are organized into five sections: problems in the analysis of the concept of information, in semantics, in the study of intelligence, in the relation between information and nature, and in the investigation of values.     

Computer Modeling and the Fate of Folk Psychology

Although Paul Churchland and Jerry Fodor both subscribe to the so-called theory-theory – the theory that folk psychology (FP) is an empirical theory of behavior – they disagree strongly about FP's fate. Churchland contends that FP is a fundamentally flawed view analogous to folk biology, and he argues that recent advances in computational neuroscience and connectionist AI point toward development of a scientifically respectable replacement theory that will give rise to a new common-sense psychology. Fodor, however, wagers that FP will be largely preserved and vindicated by scientific investigations of behavior. Recent findings by developmental psychologists, I argue, will push both Churchlandians and Fodorians toward the pessimistic view that FP is a misguided theory that will never be displaced, because it is, so to speak, built into our cognitive systems. I explore the possibility of preserving optimism by rejecting the theory-theory and adopting the simulation theory , a competing view developed by Robert Gordon, Alvin Goldman, and Jane Heal. According to simulationists, common-sense interpretation of behavior is accomplished by means of pretense-like operations that deploy the cognitive system's own reasoning capabilities in a disengaged manner. Since on this view no theory-like set of principles would be needed, the simulation theory seems to enjoy a simplicity advantage over the theory-theory. Steven Stich and Shawn Nichols, however, contend that as the cognitive system would require special mechanisms for disengaged operation, the simplicity question cannot be resolved until suitable computational models are developed. I describe a set of models I have constructed to meet this need, and I discuss the contribution such models can make to determining FP's fate.     

Book Reviews

Books reviewed:
James Campbell, Recovering Benjamin Franklin
Elliot L. Jurist, Beyond Hegel and Nietzsche: Philosophy, Culture, and Agency     

The case for responsibility of the IT industry to promote equality for women in computing

This paper investigates the relationship between the role that information technology (IT) has played in the development of women’s employment, the possibility of women having a significant influence on the technology’s development, and the way that the IT industry perceives women as computer scientists, users and consumers. The industry’s perception of women and men is investigated through the portrayal of them in computing advertisements. While women are increasingly updating their technological skills and know-how, and through this process are entering some positions in the workplace traditionally occupied by men, these achievements are not mirrored in their social and occupational status. The computer industry and higher education have worryingly low numbers of women, while the possibility of women influencing the development of computer technology is just emerging in feminist research. This paper argues that, though the IT industry, through their self-regulatory codes, subscribes to equal treatment of sexes, races and persons with disabilities, the industry nevertheless paints a stereotyped picture of inequality when portraying men and women in computer advertisements. As long as such a perception of women prevails within the industry, it will stand as a barrier to women having equal access to computer technology. If advertisements influence the way society perceives major social constructs and issues, then the computing industry has a social responsibility to portray men and women in an equal and non-stereotypical fashion. An earlier version of this paper was presented at the ETHICOMP98 Conference, Rotterdam, Holland, March 1998.     

Novice construction of chess memory

Novice acquisition of skilled recall of chess positions was studied in an experiment in which two novices studied a series of five hundred chess positions during a period of several months. They spent fifteen minutes to half an hour a day teaching themselves these positions. As a result their skill in recalling chess positions rose from sixteen percent to somewhere between forty to fifty percent. The learning curve proved to have a shape which indicates that in the beginning learning is very fast but after some 100-150 studied positions the speed of learning decreases substantially. A computer simulation was used to model the results and analyse alternative explanations. Two alternative ways of thinking were tested. In the first, chunk construction was assumed to be based on the neighbourhood of associated pieces. The second model assumed a frequency-based correlative association process. Although the learning curves of the two models are very similar in shape to those of the subjects, the frequency-based associative model gave a better explanation for the data. This is why it is natural to suggest that common co-occurrence in addition to easily recognizable chess-specific characteristics, like colour and type of pieces, guide associative processes during chess players' learning of chess-specific chunks.