Search results for "Modélisation"
showing 10 items of 222 documents
Apprend-on mieux en école rurale ?
2007
07121
Modèle dynamique multiniveau et holonique pour la simulation d'un système complexe à grande échelle avec environnement spatial : Application à la sim…
2020
Nowadays, with the emergence of connected objects and cars, road traffic systems become more and more complex and exhibit hierarchical behaviours at several levels of detail. The multilevel modeling approach is an appropriate approach to represent traffic from several perspectives. Multilevel models are also an appropriate approach to model large-scale complex systems such as road traffic. However, most of the multilevel models of traffic proposed in the literature are static because they use a set of predefined levels of detail and these representations cannot change during simulation. Moreover, these multilevel models generally consider only two levels of detail. Few works have been inter…
Les modèles multiniveaux dans l'analyse écologique : le cas de la recherche en éducation
1997
Multilevel analysis are a recent development of mathematical modelling, adapted to the problem of ecological analysis in social sciences, in other words capable of producing the effects of surroundings on individuals' behaviour. One of the ideal fields for multilevel analysis is in the educational sector, where students' learning takes place in particular class and on particular premises. This article is concerned with a comparison between the classical treatment and the multilevel treatment of the problem of ecological analysis, from both a theorical and an empirical results point of view.
Dissimilar joining of copper to stainless steel and TA6V to stainless steel by high power beams : understanding and modeling of physicochemical pheno…
2010
The present study is dedicated to the comprehension of the mechanism of materials mixing during dissimilar welding by high power beam sources. We have been interested in joining of two couples of metallic materials which present different metallurgical problems: •copper- stainless steel (miscibility gap, important difference in physical properties);•TA6V- stainless steel (oxidation on air, formation of intermetallic phases which made the joint brittle).For the first couple of materials, continuous laser Nd:YAG welding and electron beam welding have been applied. The experimental study of morphology evolution, composition, microstructure and mechanical properties has allowed establishing the…
Empirical tests of the multicentric urban models
1999
Since the seventies the effects of city size growth and diversification of economic activities on the multipolarisation of economic activities have questioned the theoretical and empirical appropriateness of the monocentric urban pattern to explain and describe the spatial organization of the modern metropolitan areas. New assumptions were based on multicentric and nonmonocentric urban economics models, which have become the core of new economic geography analysis during the nineties. At the same time, a lot of empirical studies have attempted to describe the urban economic patterns of North American metropolitan areas. Using this empirical literature, the aim of this paper is to propose a …
Construction et évaluation d’un modèle de simulation dans un contexte interdisciplinaire
2015
Le travail présenté ici s’inscrit dans le cadre de l’ANR TransMonDyn, qui vise à étudier les transformations dans les systèmes de peuplement sur le temps long, au moyen de modèles conceptuels ou implémentés sous forme informatique. Cette étude s’appuie sur un formalisme, développé au sein du projet, définissant la transformation comme une transition entre un régime 1 et un régime 2. Le projet TransMonDyn repose sur l’analyse d’un ensemble de douze cas d’études empiriques, les transitions, dont les localisations autant que les échelles spatiales et temporelles sont extrêmement diverses.
Original strain energy density functions for modeling of anisotropic soft biological tissue
2017
This thesis has focused on the construction of strain energy densities for describing the non-linear behavior of anisotropic materials such as biological soft tissues (ligaments, tendons, arterial walls, etc.) or fiber-reinforced rubbers. The densities we have proposed have been developed with the mathematical theory of invariant polynomials, particularly the Noether theorem and the Reynolds operator. Our work involved two types of anisotropic materials, the first with a single fiber family and the second with a four-fiber family. The concept of polyconvexity has also been studied because it is well known that it plays an important role for ensuring the existence of solutions. In the case o…
RVVS 2013
2013
Matériaux composites soumis à de grandes vitesses de sollicitation
2006
International audience; L'objet de ce travail est de modéliser la réponse à des sollicitations quasi-statiques et dynamiques de deux matériaux composites utilisés dans l'industrie automobile : un tissu verre/polypropylène et une matrice polypropylène renforcée de fibres courtes en verre. Pour ce faire, des essais mécaniques à différentes vitesses de sollicitation (de 10-4s-1 à 100s-1 ) ont été menés. La campagne expérimentale nous a permis d'identifier pour chacun des matériaux les phénomènes dissipatifs prépondérants et de quantifier leur part dans la déformation totale, en fonction de la vitesse. Nous proposons ensuite un modèle unifié de comportement permettant de répondre de manière coh…
Agroecological engineering
2015
Earth has recently entered the new era of the Anthropocene, during which the rise of human activities are impacting for the first time ecosystems and climate on the global scale. Since the 1960s the green revolution has improved food production in quantity using industrially-designed agriculture, which has led to global pollution by pesticides and losses of food quality, biodiversity and soil carbon. As a consequence there is a need to implement agroecological practices in order to produce food safely and in a sustainable way. This virtual issue presents principles and applications of agroecological engineering, exemplified in 19 selected review articles from the journal Agronomy for Sustai…