Une institution en quête de légitimité : le contrat stratégique pour l'Ecole en Communauté française de Belgique

Cette intervention visait à interroger les difficultés existantes dans l'école secondaire de la Communauté française de Belgique et susceptibles d'entraver la mise en oeuvre du programme éducatif affirmé dans le Contrat stratégique pour l'Ecole

Organisation du système scolaire et éducation religieuse en Belgique francophone : une rencontre plus complexe

Au départ de constats tirés d'une pratique de formateur d'enseignants et d'une recherche réalisée dans une école primaire officielle auprès d'enfants qui étaient interrogés sur leurs représentations de la mort, la question du traitement de l'éducation religieuse par l'école en CFWB est posée en trois étapes : les dispositions institutionnelles qui tendent à exacerber les différences ; les visions du monde portées par des références religieuses ; les modalités de contrôle exercées sur les cours philosophiques

Growing dust grains in protoplanetary discs - I. Radial drift with toy growth models

In a series of papers, we present a comprehensive analytic study of the global motion of growing dust grains in protoplanetary discs, addressing both the radial drift and the vertical settling of the particles. Here we study how the radial drift of dust particles is affected by grain growth. In a first step, toy models in which grain growth can either be constant, accelerate or decelerate are introduced. The equations of motion are analytically integrable and therefore the grains dynamics is easy to understand. The radial motion of growing grains is governed by the relative efficiency of the growth and migration processes which is expressed by the dimensionless parameter Lambda, as well as the exponents for the gas surface density and temperature profiles, denoted p and q respectively. When Lambda is of order unity, growth and migration are strongly coupled, providing the most efficient radial drift. For the toy models considered, grains pile up when -p+q+1/2<0. Importantly, we show the existence of a second process which can help discs to retain their solid materials. For accelerating growth, grains end up their migration at a finite radius, thus avoiding being accreted onto the central star.Comment: 12 pages, 9 figures. Accepted for publication in MNRAS. v2: typos correcte

Calibration and improved prediction of computer models by universal Kriging

This paper addresses the use of experimental data for calibrating a computer model and improving its predictions of the underlying physical system. A global statistical approach is proposed in which the bias between the computer model and the physical system is modeled as a realization of a Gaussian process. The application of classical statistical inference to this statistical model yields a rigorous method for calibrating the computer model and for adding to its predictions a statistical correction based on experimental data. This statistical correction can substantially improve the calibrated computer model for predicting the physical system on new experimental conditions. Furthermore, a quantification of the uncertainty of this prediction is provided. Physical expertise on the calibration parameters can also be taken into account in a Bayesian framework. Finally, the method is applied to the thermal-hydraulic code FLICA 4, in a single phase friction model framework. It allows to improve the predictions of the thermal-hydraulic code FLICA 4 significantly

Cartographic Generalisation Aware of Multiple Representations

posterInternational audienc

A framework to formalize multi-scales land-use generalization in the ScaleMaster 2.0

shortInternational audienceThis article presents a general framework to formalize the generalization of land-use coverages within the ScaleMaster2.0 model, a multi-scale automatic generalization system, developed to facilitate smooth transitions (i.e. cartographic continuum) between level of details in a multi-representation database (MRDB). The article describes the land-use simplification method developed, the strategy used to manage generalization on large areas, and the way to formalize multi-scales land-use generalization rules in the ScaleMaster2.0. Finally, an experiment is provided on two da-tasets to illustrate the proposition: a land-use coverage in the area of Dakar (Senegal) and a map of sedimentary floor off the coast of Brittany (France)

Generalising Unusual Map Themes from OpenStreetMap

workshopInternational audienc

Recursive regularization step for high-order lattice Boltzmann methods

A lattice Boltzmann method (LBM) with enhanced stability and accuracy is presented for various Hermite tensor-based lattice structures. The collision operator relies on a regularization step, which is here improved through a recursive computation of non-equilibrium Hermite polynomial coefficients. In addition to the reduced computational cost of this procedure with respect to the standard one, the recursive step allows to considerably enhance the stability and accuracy of the numerical scheme by properly filtering out second (and higher) order non-hydrodynamic contributions in under-resolved conditions. This is first shown in the isothermal case where the simulation of the doubly periodic shear layer is performed with a Reynolds number ranging from $10^4$ to $10^6$, and where a thorough analysis of the case at $Re=3\times 10^4$ is conducted. In the latter, results obtained using both regularization steps are compared against the BGK-LBM for standard (D2Q9) and high-order (D2V17 and D2V37) lattice structures, confirming the tremendous increase of stability range of the proposed approach. Further comparisons on thermal and fully compressible flows, using the general extension of this procedure, are then conducted through the numerical simulation of Sod shock tubes with the D2V37 lattice. They confirm the stability increase induced by the recursive approach as compared with the standard one.Comment: Accepted for publication as a Regular Article in Physical Review

Y-a-t-il des outils de réforme et de gestion de la politique étrangère française ?

En France, la politique étrangère est si proche de l’absolu régalien, de l’essence même de la souveraineté nationale, qu’elle ne peut être traitée comme les autres politiques publiques. En effet, la politique étrangère se réforme, ou plus précisément, elle se refonde et se réoriente. Pour autant, elle n’a jamais fait l’objet d’un « livre blanc » comme c’est le cas dans d’autres pays. L’absence de « livre blanc » s’explique par le caractère singulier de la politique étrangère face aux autres politiques gouvernementales. Le processus décisionnel demeure en apparence dispersé et éclaté entre plusieurs acteurs de premier rang. L’absence de livre blanc permet d’expliquer certaines lacunes, plus particulièrement au niveau de la prospective. Malgré des tentatives de réformes, les pratiques d’élaboration et d’énonciation de la politique étrangère devront changer dans le contexte européen.The creation of foreign policy in France is near the core of a definition of French national sovereignty and the regalian power. As such, it cannot be treated in the same way as other areas of public policy. Indeed, French foreign policy develops along its own path compared with the foreign policy of other countries and with the policy formation in domestic areas. France, unlike other countries, does not have a tradition of white papers in foreign affairs. This situation could be explained by the special place of foreign policy compared to that of other government policies. Control of the decision-making process is dispersed between a multitude of stakeholders. The absence of a white paper approach may explain particular analytical gaps. However French foreign policy will ultimately be forced to change, even converge, by the wider European context