Operational and denotational semantics of prolog

AbstractA Vienna Definition Language operational semantics of PROLOG, which includes the cut, the database, and the extra-logical operations, is presented. This semantics serves as the basis for deriving a denotational-continuation-style semantics of PROLOG through a systematic transformation of the operational semantics by a method described by Berry

Social construction of information technology supporting work

In the beginning of 1999, the CIO of a Portuguese company in the automobile industry was debating with himself whether to abandon or to continue supporting the MIS his company had been using for years. This MIS had been supporting the company’s production processes and the procurement of resources for these processes. However, in spite of the fact that the MIS system had been deployed under the CIO’s tight control, the CIO felt strong opposition to the use of this MIS system, opposition that was preventing the MIS system from being used to its full potential. Moreover, the CIO was at lost as to how to ensure greater compliance to his control and fuller use of the MIS system. Therefore, the CIO decided that he needed someone external to the company to help him understand the fundamental reasons, technical, social, or cultural, for the opposition to the MIS system

AB and Berry phases for a quantum cloud of charge

We investigate the phase accumulated by a charged particle in an extended quantum state as it encircles one or more magnetic fluxons, each carrying half a flux unit. A simple, essentially topological analysis reveals an interplay between the Aharonov-Bohm phase and Berry's phase.Comment: 10 pages, TAUP 2110-93. Te

The REVERE project:Experiments with the application of probabilistic NLP to systems engineering

Despite natural language’s well-documented shortcomings as a medium for precise technical description, its use in software-intensive systems engineering remains inescapable. This poses many problems for engineers who must derive problem understanding and synthesise precise solution descriptions from free text. This is true both for the largely unstructured textual descriptions from which system requirements are derived, and for more formal documents, such as standards, which impose requirements on system development processes. This paper describes experiments that we have carried out in the REVERE1 project to investigate the use of probabilistic natural language processing techniques to provide systems engineering support

Self-Efficacy and Adult Development

A major theme in the contemporary study of human development across the life span is that people have the capacity for personal agency. Innumerable writers emphasize that individuals can exert intentional influence over their experiences and actions, the circumstances they encounter, the skills they acquire, and thus ultimately the course of their development

An Information Retrieval Approach for Automatically Constructing Software Libraries

Although software reuse presents clear advantages for programmer productivity and code reliability, it is not practiced enough. One of the reasons for the only moderate success of reuse is the lack of software libraries that facilitate the actual locating and understanding of reusable components. This paper describes a technology for automatically assembling large software libraries which promote software reuse by helping the user locate the components closest to her/his needs. Software libraries are automatically assembled from a set of unorganized components by using information retrieval techniques. The construction of the library is done in two steps. First, attributes are automatically extracted from natural language documentation by using a new indexing scheme based on the notions of lexical affinities and quantity of information. Then a hierarchy for browsing is automatically generated using a clustering technique which draws only on the information provided by the attributes. Thanks to the free-text indexing scheme, tools following this approach can accept free-style natural language queries. This technology has been implemented in the GURU system, which has been applied to construct an organized library of AIX utilities. An experiment was conducted in order to evaluate the retrieval effectiveness of GURU as compared to INFOEXPLORER a hypertext library system for AIX 3 on the IBM RISC System/6000 series. We followed the usual evaluation procedure used in information retrieval, based upon recall and precision measures, and determined that our system performs 15% better on a random test set, while being much less expensive to build than INFOEXPLORER

Chaos in computer performance

Modern computer microprocessors are composed of hundreds of millions of transistors that interact through intricate protocols. Their performance during program execution may be highly variable and present aperiodic oscillations. In this paper, we apply current nonlinear time series analysis techniques to the performances of modern microprocessors during the execution of prototypical programs. Our results present pieces of evidence strongly supporting that the high variability of the performance dynamics during the execution of several programs display low-dimensional deterministic chaos, with sensitivity to initial conditions comparable to textbook models. Taken together, these results show that the instantaneous performances of modern microprocessors constitute a complex (or at least complicated) system and would benefit from analysis with modern tools of nonlinear and complexity science

Correlations of chaotic eigenfunctions: a semiclassical analysis

We derive a semiclassical expression for an energy smoothed autocorrelation function defined on a group of eigenstates of the Schr\"odinger equation. The system we considered is an energy-conserved Hamiltonian system possessing time-invariant symmetry. The energy smoothed autocorrelation function is expressed as a sum of three terms. The first one is analogous to Berry's conjecture, which is a Bessel function of the zeroth order. The second and the third terms are trace formulae made from special trajectories. The second term is found to be direction dependent in the case of spacing averaging, which agrees qualitatively with previous numerical observations in high-lying eigenstates of a chaotic billiard.Comment: Revtex, 13 pages, 1 postscript figur