Cours d'eau ; Géométrie hydraulique ; Modèle ; Modèle cellulaire
Channel geometry ; Model ; Stream
This paper outlines the principles of cellular modelling in fluvial geomorphology and addresses issues of model formulation and validation in the context of numerical modelling more generally. In doing so it seeks to highlight the prospects
for using cellular approaches to develop an improved understanding of both rivers and models.
Braided channel ; Channel geometry ; Concept ; Fluvial dynamics ; Model ; Numerical model ; Stream
The AA. test the representation of braided channel morphodynamics in the Murray-Paola model, MP model, against the known characteristics (mainly from a sequence of high resolution digital elevation models) of a physical model of a braided stream
. It achieves this by initiating the model from real braided topography rather than white noise. This extension of the application of the MP model is used to identify characteristics that are not reproduced, to investigate their causes, propose modifications
and discuss both the implications for the formation of braiding and alternative modelling strategies.
Central places ; Economic model ; Geography ; Mathematical model ; Model ; Urban model
Parmi les nombreuses définitions géographiques du terme de modèle, l'A. retient la plus efficace, celle selon laquelle le modèle est une simplification de la réalité territoriale, exprimée schématiquement, et qui permet d'avoir une perception
globale et souvent immédiate des phénomènes géographiques. L'article, après avoir examiné les rapports entre modèles et paradigmes, décrit les diverses catégories de modèles. - (MR)
Concept ; Dynamic model ; Economic theory ; Fractal geometry ; Model ; Random process ; Statistics ; Stochastic model
The A. concludes that « in spite of its simplicity (no exogenous uncertainty, no inventories, no capital, etc.), the basic structure implies a highly complex nonlinear dynamic model which generates cycles of high order as well as irregular behavior
endogenously ». Application of the theory of fractals to Keynesian models. - (CN)
Choice ; Mathematics ; Model ; Probability ; Stochastic model ; Utility fonction
The invariance property is noteworthy as it applies to the multinomial logit model or to the generalized extreme-value models. It constitutes a major problem for these models. However, the AA. argue that it is a useful theoretical concept precisely
by bringing out heterogeneity. An alternative representation of the class of random utility models possessing the invariance property is suggested. The characterization is stated in terms of the choice probabilities, and of the probability distribution
This article focuses the attention on energy models in relation to spatial systems. After a discussion of three types of methods used in the field of energy modelling (econometric models, input-output analysis and programming models), the framework
of a multi-component regional energy-econometric model is presented.
Behaviour ; Decision ; Model ; Probability ; Space time ; Spatial behaviour ; Spatial choice ; System
These models are suggested as a means for bridging the methodological and philosophical gap between models of discretionary and constrained spatial behavior. The focus is on psychologically justifiable rather than normative decision models.
Afrique du Sud ; Eolien ; Littoral ; Modèle ; Vent
Coastal environment ; Eolian features ; Model ; South Africa ; Wind
Three boundary layer models are applied to a wind energy siting investigation in the Saldanha Bay area. The different models were then tested and results compared. Favourable results were obtained for further development of the models. - (AJC)
Optimal models of river branching angles in Models in geomorphology.
Angle de confluence ; Cours d'eau ; Géographie physique ; Géomorphométrie ; Modèle ; Optimisation ; Réseau de drainage
Derives an optimality model for the geometry of stream junctions and discusses the effects on angles of the two parameters that compose the general optimal angular geometry models.
Utilisation d'un modèle analytique incluant un modèle de précipitation, un modèle d'écoulement et un modèle d'érosion permettant d'établir la densité de drainage d'un bassin-versant.
A way of modelling investment in a multisectoral model
Capacité de production ; Capitaux ; Géographie humaine ; Investissement ; Modèle multisectoriel ; Modélisation ; Prix ; Secteur économique ; Technologie ; Travail
The paper contains an example of how to introduce heterogeneity of capital in the model framework given by Leif Johansen's so called MSG-model. Heterogeneity of capital is in terms of differences among sectors and differences among vintages
Les modèles implicites dans l'enseignement de la géographie
Centre-périphérie ; Didactique ; Enseignement de la géographie ; Généralités sur la géographie ; Modèle ; Modèle explicite ; Modèle implicite ; Modèle zonal
Les modèles implicites dans l'enseignement de la géographie sont véhiculés dès le cours élémentaire, en particulier le modèle zonal ne correspondant pas à la réalité. Le modèle centre-périphérie serait plus adapté pour rendre compte des réalités