Search results for "Modélisation"

L'approche sociologique des effets du contexte scolaire: méthodes et difficultés

2005

05058; International audience; L'analyse des effets contextuels dans le domaine de l'éducation constitue un champ derecherche en plein développement, dont les enjeux sont autant scientifiques que politiques.Le texte présente de manière précise comment les chercheurs en Education dont l'orientationest sociologique (ou économique) abordent ces questions, à partir d'une enquête récente,conduite au niveau de l'école primaire française, permettant d'évaluer et d'explorer ce typed'effets, en se focalisant sur l'influence de la composition sociale de la classe fréquentée. Letexte explicite la démarche et les étapes successives suivies, les modèles statistiques estiméset les difficultés méthodologi…

Modeling and numerical simulation of the propagation of pitting corrosion of iron in chlorinated medium : contribution to the evaluation of the durab…

2012

This study deals with the understanding of the mechanisms of pitting corrosion susceptible to occur on carbon steel selected for high level nuclear waste containers. Transport/reaction models have been developed in order to simulate, by finite element method, the propagation of a pit on iron in chlorinated medium. For conservative models, pit is activated by imposing a potential on metal. Thanks to different parametric studies (geometry, environment…) simulations have permitted to classify, by severity order, the factors responsible of the increase or the inhibition of the localized corrosion rate. Otherwise, experiments on occluded (called « lead-in-pencil ») electrodes confirm that confin…

Essai de Modélisation du Comportement du Public de Théâtre : une Approche Conceptuelle et méthodologique

1995

Les traces de la vitesse entre réseau et territoire : approche géohistorique de la croissance du réseau ferroviaire français

2016

The interaction between space and network are frequently questioned in the academic literature, by asking the economical and demographical impacts of a new infrastructure, often studied at the scale of a project. This work aims to investigate the components of the interaction in both large spatial and temporal scales. The hypothesis is that the temporal depth and the national scale could bring new explanations. This work is based on the collect, the exploitation and the analysis of the large spatio-temporal database FRANcE (French Railway Network). It identifies all sections of the network since the 19th century and the population census. This database also contains the traces of the speed,…

Précipitations et relief en Afrique orientale et australe : modélisations statistiques et géostatistiques.

2008

By considering two examples in Eastern and Southern Africa, this work has two aims: a better understanding of the influence of topography on the spatial distribution of rainfall and an optimal interpolation of station rainfall data, taking into account topography. To this end, an original methodology is developped, partly derived from previous studies focusing on extratropical regions.First, a statistical model is defined. With the help of a multi-scalar decomposition of topographical information into descriptors, a multiple linear regression is performed. This model is used to better understand the relationship between rainfall and topography. In Eastern Africa, the spatial distribution of…

Modélisation dynamique de la croissance d'un réseau de transport : méthodes mixtes pour l'explication des écarts au modèle

2019

International audience; Les effets territoriaux du développement des infrastructures de transport font l’objet d’une littérature abondante et suscite une controverse scientifique qui est régulièrement réactivée. Quand certains dénoncent les négligences méthodologiques (Offner, 1993, 2014) associée à une pression politique voire idéologique, d’autres ont cherché minutieusement à regarder l’évolution parallèle des réseaux et des trajectoires démographiques dans une perspective de longue durée (Bretagnolle, 1999, 2003, 2010 ; Mimeur et al., 2017) en concluant à une coévolution des deux systèmes. Il en ressort qu’une attention particulière doit être apportée aux contextes territoriaux dans lesq…

Integration of thermal building simulation and VR techniques for sustainable building projects

2013

Déjà présent sur HAL mais sans le fichier pdf; The importance of energy efficiency and integration of advances in building design and VR technology have led this research to focus on thermal simulation results visualized in a virtual environment to optimize building design. This paper combines the principle of integration for thermal calculation and scientific visualization in VR. The method is to use CAD models (extensively used in architectural design) to analyze a building's thermal performance and visualize it, as well as simulating it through VR technology. Interaction between users and objects in a virtual world are certainly through techniques of visualization metaphors. The object o…

Exploration of future changes of residential locations in an urban agglomeration using an individual-based simulation model (Mobisim)

2015

To ensure that housing supply is suitable to households’ needs and preferences represents a major planning concern. These needs and preferences depend on the households’ characteristics and on their lifecycle changes (union, birth, divorce…). Residential choice factors are numerous (housing and residential environment characteristics) and their role is often different according to the types of households. Residential dynamics involve a great variety of elements, in interaction with each other, and the causal relationships are difficult to identify. Thus, it is not possible to predict the households’ residential behaviour, nor their possible evolutions, without a suitable tool. To study intr…

Etude de l'influence de l'hydratation des laitiers sur les propriétés de transfert gazeux dans les matériaux cimentaires

2015

Cements with high slag content are currently studied as possible candidate for nuclear waste containment materials. In this context it is important to know their microstructure and the transport properties (permeability and diffusion) of the gases that are formed by the radiolysis of the water present in this material. According to literature, these properties are strongly impacted by the addition of blast furnace slag. The aim of this work is to correlate the hydration processes of slag blended cements with their transport properties. In the first part of this work, the hydration of the slag blended cements, for which only few results have been reported to date, has been studied. Silicon-2…

Probabilité d'apparition d'un phénomène parasitaire et choix de modèles de régression logistique

2007

Epidemiological processes are now using spatial statistics and modelling tools. The main objective of most health risks studies consists in identifying potential contamination sources and factors capable of explaining their localization. Health data often prove binary (typically presence/absence) and specific methods such as binary logistic regression have to be used. This method's output consists in a probability for the pathogen of interest. A posterior classification of each sample is then conducted using a probability threshold. The method used to maximize this threshold is called the ROC curve which consists in giving a representation of the behaviour of the model and then to choose th…