Search results for "Modèle"
showing 10 items of 311 documents
Modélisation du comportement des agriculteurs face au risque dans un modèle de programmation mathématique positive (PMP) à grande échelle
2017
Agricultural production is characterized for being a risky business due to weather variability, market instability, plant diseases as well as climate change and political economy uncertainty. The modelling of risk at farm level is not new, however, the inclusion of risk in Positive Mathematical Programming (PMP) models is particularly challenging. Most of the few existing PMP-risk approaches have been conducted at farm-type level and for a very limited and specific sample of farms. This implies that the modelling of risk and uncertainty at individual farm level and in a large scale system is still a challenging task. The aim of this paper is to formulate, estimate and test a robust methodol…
Le prix des paysages périurbains
2007
L'évaluation économique du prix des paysages périurbains utilise des analyses géographiques (occupation des sols, composition paysagère, distance à des biens paysagers, paysages vus : champ de vision, objets, formes). L'article fait le point sur la littérature en matière de méthode et de résultats et présente l'estimation du prix d'attributs paysagers dans la ceinture périurbaine de Dijon.
GEOV1: LAI, FAPAR essential climate variables and FCOVER global time series capitalizing over existing products. Part 2: Validation and intercomparis…
2013
International audience; This paper describes the scientific validation of the first version of global biophysical products (i.e., leaf area index, fraction of absorbed photosynthetically active radiation and fraction of vegetation cover), namely GEOV1, developed in the framework of the geoland-2/BioPar core mapping service at 1 km spatial resolution and 10-days temporal frequency. The strategy follows the recommendations of the CEOS/WGCV Land Product Validation for LAI global products validation. Several criteria of performance were evaluated, including continuity, spatial and temporal consistency, dynamic range of retrievals, statistical analysis per biome type, precision and accuracy. The…
Le site de Gaillardon à Ménétru-le-Vignoble (Jura) : un établissement de hauteur de l'Antiquité tardive et du haut Moyen Âge
2011
L'étude de l'établissement de Gaillardon à Ménétru-le-Vignoble s'inscrit dans le cadre d'un programme de recherche pluridisciplinaire engagé sur les sites de hauteur de l'Antiquité tardive et du haut Moyen Âge dans le département du Jura. Créé ex nihilo vers le début du ve siècle, ce lieu semble avoir été occupé de manière permanente jusqu'au vie siècle. Les aménagements identifiés à l'intérieur de l'enceinte maçonnée, qui enserre une superficie de 1,5 ha, suggèrent une concentration d'activités artisanales diversifiées. Certaines catégories de mobilier reflètent un niveau de vie aisé d'une partie des occupants ainsi que la présence d'une garnison ou d'une milice armée. Cet établissement pa…
Bias correction of dynamically downscaled precipitation to compute soil water deficit for explaining year-to-year variation of tree growth over north…
2017
This paper documents the accuracy of a post-correction method applied to precipitation regionalized by the Weather Research and Forecasting (WRF) Regional Climate Model (RCM) for improving simulated rainfall and feeding impact studies. The WRF simulation covers Burgundy (northeastern France) at a 8-km resolution and over a 20-year long period (1989–2008). Previous results show a strong deficiency of the WRF model for simulating precipitation, especially when convective processes are involved. In order to reduce such biases, a Quantile Mapping (QM) method is applied to WRF-simulated precipitation using the mesoscale atmospheric analyses system SAFRAN («Système d'Analyse Fournissant des Rense…
Bias the estimates of the returns ot education in the Mincerian earnings functions as a result of cohort effects
1986
Estimations de la rentabilité des études dans les fonctions de gains : problèmes de spécification, effets de génération
1986
Modelling and development of a generic observatory to harvest and analyze big data
2021
Big Data fascinate, both because of the value they hold that can provide a significant advantage in decision-making, and because of the challenges that their exploitation represents. These challenges are present at several levels of analytics workflows. At the level of the creation of software architectures, the volume and the velocity require at least enough performance to handle the ingestion and storage of data. The data variety has also an impact, as several new storage systems have emerged, each one corresponding to a specific need. The polystores are systems that integrate this diversity, to gain flexibility compared to the data warehouses, now too rigid. However, this diversification…
Climate change impact on the West African monsoon from June to October.
2015
Sixteen CMIP5 models are used toanalyse how climate changes over the West African Monsoon region between a “future period”, defined from 2031 to 2070under the rcp4.5 emission scenario, and the “current period”, defined from 1960 to 1999 under the historical emissionscenario. The results show an increase of the September to October rainfall amounts. Circulation anomalies include of anincreases of sea-level pressure over the Mediterranean Sea and Europe that allow a strengthening of the moisture flux fromEuro-Mediterranean regions into the Sahel. These changes are stronger in autumn.
The climate change effect on the african monsoon region : evolution of the precipitation and atmospheric fields in the CMIP3 and CMIP5 simulations un…
2013
The fourth IPCC report in 2007 established the synthesis of previously published work onthe effects of climate change on global and regional scales. It shows in particular that no consensuscan be found with regard to the future of rainfall — and atmospheric dynamics- associatedwith region — African monsoon. This dissertation revisits this issue in the light of new dataand using an approach avoiding over-representation of the number of simulations available forone type of model and taking into account the diversity of models and their evolution in time :twenty general circulation models (GCMs) participating in the exercises CMIP3 (twelve GCMs)and CMIP5 (eight GCMs) under the A1B emissions sc…