Le système informatique GEMAU

GEMAU is a software system for writing and adapting computer operating systems, especially in electronic switching. It generates abstract or virtual machines in formalizing the notions of objects and of relations between these objects. Solutions are proposed for banalisation, hierachy, protection, acces control mechanisms, execution and representation domains.     

Étude par microscopie électronique de composés NbGe,NbSi et NbGeSi de structure A15

NbGe, NbSi and NbGeSi compounds with the A15 structure, produced by chemical vapour deposition, were examined by transmission electron microscopy. These examinations showed that inhomogeneities, voids, precipitates and fibrous zones were embedded in the A15 matrix of the grains. The results are correlated with the superconducting properties of the materials and are discussed in terms of the instability of the A15 phase.     

Optical rotation of branched polysaccharides

Summary Correlation between optical activity and conformational behavior is attempted for the series of oligomannosides and pure mannan polysaccharide. Then, the principle of decomposing the contribution to optical rotation into some basic components is extended to the case of branched polymers. It is shown that the derived relationship fits the experimental rotation data gathered for this series. Conclusions about the influence of branching on solution behavior of galactomannan chains are drawn.     

Expert guided integration of induced knowledge into a fuzzy knowledge base

This paper proposes a method for building accurate and interpretable systems by integrating expert and induced knowledge into a single knowledge base. To favor the cooperation between expert knowledge and data, the induction process is run under severe constraints to ensure the fully control of the expert. The procedure is made up of two hierarchical steps. Firstly, a common fuzzy input space is designed according to both the data and expert knowledge. The compatibility of the two types of partitions, expert and induced, is checked according to three criteria : range, granularity and semantic interpretation. Secondly, expert rules and induced rules are generated according to the previous common fuzzy input space. Then, induced and expert rules have to be merged into a new rule base. Thanks to the common universe resulting from the first step, rule comparison can be made at the linguistic level only. The possible conflict situations are managed and the most important rule base features, consistency, redundancy and completeness, are studied. The first step is thoroughly described in this paper, while the second is only introduced.     

Efficient numerical solution of Neumann problems on complicated domains

Abstract We consider elliptic partial differential equations with Neumann boundary conditions on complicated domains. The discretization is performed by composite finite elements. The a priori error analysis typically is based on precise knowledge of the regularity of the solution. However, the constants in the regularity estimates possibly depend critically on the geometric details of the domain and the analysis of their quantitative influence is rather involved. Here, we consider a polyhedral Lipschitz domain Ω with a possibly huge number of geometric details ranging from size O(ε) to O(1). We assume that Ω is a perturbation of a simpler Lipschitz domain Ω. We prove error estimates where only the regularity of the partial differential equation on Ω is needed along with bounds on the norm of extension operators which are explicit in appropriate geometric parameters. Since composite finite elements allow a multiscale discretization of problems on complicated domains, the linear system which arises can be solved by a simple multi-grid method. We show that this method converges at an optimal rate independent of the geometric structure of the problem.     

Knowledge-based Intelligent Diagnosis of Ground Robot Collision with Non Detectable Obstacles

The paper describes the application of fuzzy techniques to analyze motion problems in a mobile robot. The robot is equipped with ultrasound sensors used for obstacle detection, but, in some cases, small obstacles are out of the range of the sensors and can be dragged by the robot without being detected. Using other variables as, measured velocity, undershoots of that velocity or changes in battery voltage, a fuzzy system is able to determine those situations. The paper also analyzes the knowledge extraction process for the application using expert and induced knowledge (from data collected during navigation tasks) in a cooperative way, dealing with integration and simplification issues. The expert knowledge was used for describing the robot behaviour in order to identify the variables that should be used with the aim of detecting a collision of the vehicle against an undetected obstacle, as well as proposing a suitable recovery action. Data collected in real trials were used for inducing knowledge so as to complete and validate the expert knowledge. Both kind of knowledge were integrated in the final fuzzy-based system. The aim is to build up a knowledge base, which is interpretable and accurate at the same time, and it is used by our fuzzy system in order to solve the motion problems under consideration.     

Recursive Petri nets

In order to design and analyse complex systems, modelers need formal models with two contradictory requirements: a high expressivity and the decidability of behavioural property checking. Here we present and develop the theory of such a model, the recursive Petri nets. First, we show that the mechanisms supported by recursive Petri nets enable to model patterns of discrete event systems related to the dynamic structure of processes. Furthermore, we prove that these patterns cannot be modelled by ordinary Petri nets. Then we study the decidability of some problems: reachability, finiteness and bisimulation. At last, we develop the concept of linear invariants for this kind of nets and we design efficient computations specifically tailored to take advantage of their structure.     

L'Année Psychologique: History of the founding of a 100-year-old French journal.

The authors present the history of the founding of the French journal L'Année Psychologique. The names of T. Ribot (1839–1916), H. Beaunis (1830–1921), and A. Binet (1857–1911) are closely associated with the journal. Ribot's election to the chair of Experimental and Comparative Psychology at the Collège de France in 1888 marked the official emancipation of psychology in France. Because there was no laboratory associated with the chair, Beaunis, a physiological psychologist from Nancy, proposed to Ribot the creation of the first French laboratory of experimental psychology (1889). Under Beaunis's direction, this laboratory was established at the Sorbonne in Paris but was in fact dependent on another educational institution, L'Ecole Pratique des Hautes Etudes. In 1893 the laboratory's research was first published in a yearly journal named Travaux du Laboratoire de Psychologie Physiologique (2 volumes: 1893–1894). Binet, who joined the laboratory in 1891, was not satisfied by the form of this publication. With Beaunis's agreement, he then created L'Année Psychologique in 1894 to develop the reputation of the laboratory's research. The authors present the evolution and vicissitudes of the journal from 1895 to 1912, with a glance up to the present. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

X‐Ray Absorption Spectroscopy Characterizations on PGM‐Free Electrocatalysts: Justification,Advantages, and Limitations

Transition metals embedded in nitrogen‐doped carbon matrices (denoted as M‐N‐C) are the leading platinum group metal (PGM)‐free electrocatalysts for the oxygen reduction reaction (ORR) in acid, and are the most promising candidates for replacing platinum in practical devices such as fuel cells. Two of the long‐standing puzzles in the field are the nature of active sites for the ORR and the reaction mechanism. Poor understanding of the structural and mechanistic basis for the exceptional ORR activity of M‐N‐C electrocatalysts impedes rational design for further improvements. Recently, synchrotron‐based X‐ray absorption spectroscopy (XAS) has been successfully implemented to shed some light on these two issues. In this context, a critical review is given to detail the contribution of XAS to the advancement of the M‐N‐C electrocatalysis to highlight its advantages and limitations.     

Mass transfer measurements and modeling in a microchannel photocatalytic reactor

The main objective of this paper was to evaluate the influence of mass transfer on the photocatalytic efficiency at a low flow rate in the order of several mL per hour. Several continuous flow microchannel reactors have been used to study the degradation of salicylic acid (SA) taken as a model pollutant. The photocatalytic degradation of salicylic acid, under UV illumination of 1.5 mW cm⁻², was assessed from the outlet concentration measured by liquid chromatography HPLC. It was shown that the degradation of SA by UV was limited by mass transfer. Numerical simulations have allowed establishing a relationship of the Sherwood number valuable for all the microchannel geometries. Computational fluid dynamics with Comsol Multiphysics is useful for predicting the degradation yield for a given geometry of the microreactor. The best representation of the experimental data is obtained by introducing a kinetic law taking into account mass transfer limitation.