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Résultats de la recherche (212 résultats)

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  • A nonlinear dynamical model of landslide evolution
  • Chaos ; Concept ; Glissement de terrain ; Géomorphodynamique ; Modèle ; Prévision ; Risque naturel ; Versant
  • Chaos ; Concept ; Earth surface processes ; Forecast ; Landslide ; Model ; Natural hazards ; Slope
  • A nonlinear dynamical model for the evolution of landslide is proposed. The parameters of this model are obtained through an improved iterative algorithm of inversion developed in the paper. Based on the nonlinear dynamical model and nonlinear
  • the capability and merit of the nonlinear dynamic model.
  • dynamical systems (NDS) theory, the approaches to determining the Lyapunov exponents, the predictable timescale and the stability criterion of the evolutional state of landslide are given. A case study of the Xintan slope is presented to illustrate
  • 2002
  • Spatial representations of habitat in competition-colonization models
  • Ecosystem ; Fractals ; Habitat ; Interspecific competition ; Model ; Population dynamics ; Simulation
  • Compétition interspécifique ; Dynamique des populations ; Ecosystème ; Fractale ; Habitat ; Modèle ; Simulation
  • Ecological models with species differentiated by competition and colonization traits analyze landscape patterns in two phases (habitat and nonhabitat). The consequences of representing landscape patterns as a continuous surface of habitat quality
  • 2002
  • Computational fluid dynamics and the physical modelling of an upland urban river
  • Cours d'eau ; Crue ; Ecoulement fluvial ; England ; Espace urbain ; Modèle ; Modèle numérique ; Risque ; Royaume-Uni ; West Yorkshire
  • England ; Flood ; Model ; Numerical model ; Risk ; Stream ; Stream flow ; United Kingdom ; Urban area ; West Yorkshire
  • This paper describes the application of a commercially available, three-dimensional computational fluid dynamic (CFD) model to simulate the flow structure in an upland river that is prone to flooding. Simulations use a rectangular channel geometry
  • , smooth sidewalls and a bed topography obtained from the field site that contains a subdued pool-riffle sequence. Results are presented from the numerical and flume models for the water surface and streamwise velocity pattern and for the secondary flows
  • simulated in the numerical model. Results suggest that the streamwise velocity is the main influence on the flow structure at the discharge and channel configuration studied.
  • 2002
  • Explaining regional economic performance : an historical application of a dynamic multi-regional CGE model
  • Australie ; Croissance économique ; Economie régionale ; Modèle ; Modèle d'entrée-sortie ; Modèle multirégional ; Niveau de vie ; Simulation ; Tasmania
  • Australia ; Economic growth ; Input-output model ; Living standard ; Model ; Multiregional model ; Regional economy ; Simulation ; Tasmania
  • Un modèle multirégional de l'économie australienne permet d'identifier les causes des performances divergentes de la croissance entre la Tasmanie (croissance plus lente) et le reste du pays. Périodes 1992-93 et 1998-99. Les facteurs possibles sont à
  • 2002
  • Dynamics of secondary airflow and sediment transport over and in the lee of transverse dunes
  • Bibliographie ; Contrainte de cisaillement ; Couche limite ; Dune ; Eolien ; Géomorphodynamique ; Modèle ; Simulation ; Transport sédimentaire ; Tunnel à vent ; Turbulence ; Vitesse du vent
  • Aeolian features ; Bibliography ; Boundary layer ; Dune ; Earth surface processes ; Model ; Sediment transport ; Shear stress ; Simulation ; Turbulence ; Wind speed
  • Recent research literature on secondary airflow and sediment transport patterns over flow-transverse dunes is reviewed. Various issues surrounding the behaviour, modelling and sedimentological implications of near-surface airflow dynamics over dunes
  • are discussed, including the Law of the Wall; the Jackson and Hunt airflow model; the effects of streamline compression, acceleration and curvature on stoss slope shear stress; and, in particular, recent efforts to characterize secondary lee-side airflow
  • patterns. A revised conceptual model of lee-side airflow is presented and areas for further research are identified.
  • 2002
  • Regolith stripping and the control of shallow translational hillslope failure : application of a two-dimensional coupled soil hydrology-slope stability model, Hawke's Bay, New Zealand
  • Geotechnics ; Hydrology ; Landslide ; Model ; New Zealand ; North Island ; Precipitation ; Regolith ; Slope ; Slope dynamics ; Soil moisture ; Threshold
  • Dynamique de versant ; Glissement de terrain ; Géotechnique ; Humidité du sol ; Hydrologie ; Modèle ; North Island ; Nouvelle-Zélande ; Précipitation ; Régolithe ; Seuil ; Versant
  • This paper explores the hypothesised influence of progressive regolith stripping and redeposition on slope failure using a recently developed process-based model. This model couples dynamic hydrology with slope stability analysis, allowing to relax
  • the previous assumption concerning the role of pore water pressures on slope stability. The model is then used to investigate both changing triggering thresholds as well as changing mechanisms for slope instability in New Zealand hill country.
  • 2002
  • Scale effects of hortonian overland flow and rainfall-runoff dynamics : laboratory validation of a process-based model
  • Echelle ; Ecoulement ; Expérimentation ; Modèle ; Orage ; Pente de versant ; Précipitation ; Simulation ; Versant
  • Experimentation ; Model ; Precipitation ; Rainstorm ; Runoff ; Scale ; Simulation ; Slope ; Slope gradient
  • lengths were increased. The runoff data were used to validate a simple process-based model that combines the Philip-two-term infiltration equation with the kinematic wave overland flow principle. The predicted and experimental results agreed well
  • . Laboratory findings were extrapolated with the aid of the model to slopes and rainfall durations similar to those found under West African conditions.
  • 2002
  • Bibliography ; Coastal dynamics ; Coastal environment ; Coastal geomorphology ; Coastal protection ; Model ; Scale ; Sediment transport
  • Bibliographie ; Dynamique littorale ; Echelle ; Géomorphologie littorale ; Littoral ; Modèle ; Protection du littoral ; Transport sédimentaire
  • Observations of mesoscale beach evolution are reviewed : observations of beach change; nearshore bar systems; long-term datasets; mesoscale modelling. As engineers and other marine scientists become increasingly interested in issues of scale
  • 2002
  • Cirque glaciaire ; Cumbria ; England ; Glaciaire ; Géomorphométrie ; Modèle ; Royaume-Uni ; Scotland ; Simulation ; Statistique
  • Cirque ; Cumbria ; England ; Geomorphometry ; Glacial features ; Model ; Scotland ; Simulation ; Statistics ; United Kingdom
  • model introduced here is far from being a complete model of cirque development. In particular it lacks the dynamics of cirque erosion and does not consider the interaction between bedrock and the cirque glacier. Rather, it is a kinematic model : certain
  • 2002
  • Alaska ; Antarctica ; Bibliography ; Concept ; Floating ice processes ; Glacier ; Glacier dynamics ; Glacier fluctuation ; Greenland ; Ice sheet ; Iceberg ; Model ; Seasonal variation
  • Alaska ; Antarctique ; Bibliographie ; Calotte glaciaire ; Concept ; Dynamique glaciaire ; Fluctuation du glacier ; Glaciel ; Glacier ; Groenland ; Iceberg ; Modèle ; Variation saisonnière ; Vêlage
  • Based on a review of observations on different types of calving glaciers, a simple calving model is proposed. Advance or retreat of the calving front is not driven by changes in the calving rate, but by flow-induced changes in the geometry
  • of the terminal region. This model is essentially different from prior suggestions in which some empirical relation - most commonly the water-depth model - is used to calculate calving rate and the rate of retreat or advance of the terminus.
  • 2002
  • Brunei ; Hydrology ; Mass movement ; Model ; Precipitation ; Slope ; Slope dynamics ; Soil erosion ; Soil moisture ; Tropical rain forest ; Tropical zone
  • Brunéi ; Dynamique de versant ; Erosion des sols ; Forêt tropicale ; Humidité du sol ; Hydrologie ; Modèle ; Mouvement de masse ; Précipitation ; Versant ; Zone intertropicale
  • also make important contributions to the ecological dynamics of the tropical rainforest system. A deterministic modelling framework based on the infinite slope model and a simple hillslope hydrology model based on water storage and the continuity
  • 2002
  • Applied geography ; Decision model ; Dynamic model ; Geographical information system ; Model ; Operational research ; Optimization ; Regional science ; Research ; Spatial analysis ; Spatial interaction
  • Analyse spatiale ; Géographie appliquée ; Interaction spatiale ; Microsimulation ; Modèle ; Modèle de décision ; Modèle dynamique ; Optimisation ; Recherche ; Recherche opérationnelle ; Science régionale ; Système d'information géographique
  • Le but de cet article est de récapituler les arguments justifiant la nécessité et les avantages de l'utilisation des systèmes d'information géographique qui permettent de réaliser des modèles d'aide à la décision dans divers domaines de la science
  • régionale. Une série d'exemples d'application pratique développée au département de géographie de l'Université de Leeds est présentée à partir de deux méthodologies principales : modèles d'interaction spatiale et modèles de microsimulation.
  • 2002
  • Concept ; Erosion ; Geomorphogenesis ; Isostasy ; Landscape dynamics ; Model ; Peneplain ; Topography
  • Concept ; Dynamique du paysage ; Erosion ; Géomorphogenèse ; Isostasie ; Modèle ; Pénéplaine ; Topographie
  • 2002
  • Alaska ; Cold area ; Forest ; Landslide ; Model ; Mountain ; Slope ; Slope dynamics ; Soil moisture ; Soil properties ; Vegetation dynamics
  • Alaska ; Cèdre ; Dynamique de la végétation ; Dynamique de versant ; Forêt ; Glissement de terrain ; Humidité du sol ; Modèle ; Montagne ; Propriétés du sol ; Versant ; Zone froide
  • ; and reduced strength of decaying roots. A simple slope stability model is used to evaluate the relative influence of soil moisture changes and loss of root strength on landslide frequency and to evaluate the timing of landslides relative to the onset of cedar
  • 2002
  • Géographies d'une ville industrielle américaine : Lowell en modèles chronographiques
  • Industrial city ; Industry ; Massachusetts ; Spatial dynamics ; Spatial organization ; Spatial structure ; United States of America ; Urban history ; Urban region
  • Des modèles chronographiques à moyenne échelle, proposant une mise en espace de Lowell au Massachusetts, prennent en compte deux siècles d'histoire industrielle. Ils présentent des systèmes spatiaux successifs transposables à beaucoup de régions
  • 2002
  • Canada ; Channel geometry ; Confluent ; Fluvial dynamics ; Numerical model ; Quebec ; Runoff ; Spatial analysis ; Stream ; Surface water ; Turbulence
  • Analyse spatiale ; Canada ; Confluence ; Cours d'eau ; Dynamique fluviale ; Eau de surface ; Ecoulement ; Géométrie hydraulique ; Modèle numérique ; Québec ; Turbulence
  • small changes in water surface height. These results are interpreted with respect to visual observations of the flow structures. Simulated water surface topography from three-dimensional numerical modelling is also compared with the detailed field
  • 2002
  • Bilan hydrique ; Biogéographie ; Etats-Unis ; Habitat ; Humidité du sol ; Hêtre ; Indice ; Modèle numérique de terrain ; Méthodologie ; Ohio ; Végétation
  • Beech ; Biogeography ; Digital elevation model ; Habitat ; Index ; Methodology ; Ohio ; Soil moisture ; United States of America ; Vegetation ; Water budget
  • . It concludes that a water-budget approach is applicable to a wide range of studies exploring vegetation-site linkages, and in terms of global change, this approach offers the additional benefit of being a dynamic model.
  • 2002
  • Direction du vent ; Domaine aride ; Désert ; Eolien ; Modèle ; Namibie ; Topographie ; Transport éolien ; Vallée ; Vent ; Vitesse du vent
  • Aeolian features ; Aeolian transport ; Arid area ; Desert ; Model ; Namibia ; Topography ; Valley ; Wind ; Wind speed
  • This paper investigates the impacts of dryland valley topography on wind speed and direction in order to understand better the effects of a valley on aeolian sediment dynamics. Anemometers and wind vanes were used to measure airflow characteristics
  • upwind, within and downwind of a dry valley in the central Namib desert. A conceptual model indicating the potential implications of these data for aeolian sediment transport processes in the vicinity of dryland valleys is presented.
  • 2002
  • Landslide characteristics and slope instability modeling using GIS, Lantau Island, Hong Kong
  • Data base ; Forecast ; Geographical information system ; Hong Kong ; Landslide ; Model ; Regression analysis ; Slope ; Slope dynamics ; Thematic map ; Tropical zone
  • Analyse de régression ; Base de données ; Carte thématique ; Dynamique de versant ; Glissement de terrain ; Hong Kong ; Modèle ; Prévision ; Système d'information géographique ; Versant ; Zone intertropicale
  • of landslide frequency with the physical parameters contibuting to the initiation of landslides on Lantau Island in Hong Kong. This GIS database is then used to obtain a logistic regression model for predicting slope instability. This model is then imported
  • 2002
  • The effects of survey frequency on estimates of scour and fill in a braided river model
  • Alberta ; Braided channel ; Canada ; Carrying capacity ; Channel geometry ; Fluvial dynamics ; Model ; Sediment transport ; Spatial analysis ; Stream
  • Alberta ; Analyse spatiale ; Canada ; Capacité de charge ; Chenal anastomosé ; Cours d'eau ; Dynamique fluviale ; Géométrie hydraulique ; Modèle ; Transport sédimentaire
  • model it is possible to essentially eliminate compensation resulting from variation in discharge by maintaining constant discharge. Also, river-bed topography can be mapped relatively easily and frequently using a flume. Hence, a small-scale braided
  • gravel-bed river model is used in this study to examine the magnitude and nature of scour-fill and to relate the spatial pattern of compensation to braided channel kinetics.
  • 2002