La méthode Inondabilité : appropriation par les hydrologues de la vulnérabilité dans le diagnostic sur le risque d'inondation

Direction d'ouvrage : Sylvia Becerra et Anne PeltierLa méthode Inondabilité a été développée dans les années 1990 par le Cemagref pour disposer d'un outil d'évaluation du risque d'inondation à l'échelle du bassin versant et proposer un cadre de négociation sur la notion de risque acceptable. Elle repose sur l'idée d'exprimer aléa (intensité physique du phénomène naturel) et vulnérabilité (sensibilité d'un usage du sol aux inondations) avec une même unité hydrologique, la période de retour. Pour l'aléa, il s'agit de la période de retour de la première crue inondante. Pour la vulnérabilité, l'usager indique le niveau de protection souhaité en terme de période de retour, le corollaire étant qu'il accepte ou tolère d'être inondé par des crues plus importantes. Après un rappel sur les principes de la méthode Inondabilité, nous présentons une discussion sur la définition hydrologique de la vulnérabilité, et un travail complémentaire effectué sur l'évaluation économique du consentement à payer pour bénéficier de mesures de protection contre les inondations. / The Inondabilite method has been developed in the nineties by Cemagref as a tool for flood risk assessment at a basin scale. The main idea was to propose a framework of negotiation on acceptable flood risk. Both components, flood hazard and flood vulnerabilty were defined as a return period, the former being related to the first overflowing event, the latter being related to the expected level of protection. After a presentation on the Inondabilite framework, a discussion gives the advantages and limitations of such hydrological assessment of flood vulnerability. A complementary work is presented on the economical assessment of the willingness of population to pay for flood risk mitigation

Stable climate and surface mass balance in Svalbard over 1979–2013 despite the Arctic warming

With the help of the regional climate model MAR (Modèle Atmosphérique Régional) forced by the ERA-Interim reanalysis (MARERA) and the MIROC5 (Model for Interdisciplinary Research on Climate) global model (MARMIROC5) from the CMIP5 (Coupled Model Intercomparison Project) database, we have modelled the climate and surface mass balance of Svalbard at a 10 km resolution over 1979–2013. The integrated total surface mass balance (SMB) over Svalbard modelled by MARERA is negative (−1.6 Gt yr−1) with a large interannual variability (7.1 Gt) but, unlike over Greenland, there has been no acceleration of the surface melt over the past 35 years because of the recent change in atmospheric circulation bringing northwesterly flows in summer over Svalbard, contrasting the recent observed Arctic warming. However, in 2013, the atmospheric circulation changed to a south–southwesterly flow over Svalbard causing record melt, SMB (−20.4 Gt yr−1) and summer temperature. MIROC5 is significantly colder than ERA-Interim over 1980–2005 but MARMIROC5 is able to improve the near-surface MIROC5 results by simulating not significant SMB differences with MARERA over 1980–2005. On the other hand, MIROC5 does not represent the recent atmospheric circulation shift in summer and induces in MARMIROC5 a significant trend of decreasing SMB (−0.6 Gt yr−2) over 1980–2005

One way to design the control law of a mini-UAV.

International audienceThis paper deals with a method used to design the control law of the μDrone MAV. This vehicle uses six propellers to fly and the dynamic model approximation for the motion is a MIMO linear time-invariant system. As we want to design a linear regulator, it is necessary to build a robust feedback control law. The LQ state feedback regulator design is applied to a standard model, tacking into account some perturbations. This is why the model is augmented with a perturbation vector and an observable subsystem is extracted in order to build a state estimator whose gain is the solution of a LQ problem. The subsystem is then decomposed into a controllable set and an uncontrollable one. The use of an asymptotic rejection strategy of the influence of uncontrollable modes gives the possibility to find a state feedback applied only to the controllable ones. Here again feedback matrix is chosen as the solution of a LQ problem. To compute the weighting matrices of quadratic criterions we use a “partial observability gramian”. The great advantage of this method is due to the use of only three scalars to synthesize the control law

La méthode Inondabilité : appropriation par les hydrologues de la vulnérabilité dans le diagnostic sur le risque d'inondation

La méthode Inondabilité a été développée dans les années 1990 par le Cemagref pour disposer d'un outil d'évaluation du risque d'inondation à l'échelle du bassin versant et proposer un cadre de négociation sur la notion de risque acceptable. Elle repose sur l'idée d'exprimer aléa (intensité physique du phénomène naturel) et vulnérabilité (sensibilité d'un usage du sol aux inondations) avec une même unité hydrologique, la période de retour. Pour l'aléa, il s'agit de la période de retour de la première crue inondante. Pour la vulnérabilité, l'usager indique le niveau de protection souhaité en terme de période de retour, le corollaire étant qu'il accepte ou tolère d'être inondé par des crues plus importantes. Après un rappel sur les principes de la méthode Inondabilité, nous présentons une discussion sur la définition hydrologique de la vulnérabilité, et un travail complémentaire effectué sur l'évaluation économique du consentement à payer pour bénéficier de mesures de protection contre les inondations. / The Inondabilite method has been developed in the nineties by Cemagref as a tool for flood risk assessment at a basin scale. The main idea was to propose a framework of negotiation on acceptable flood risk. Both components, flood hazard and flood vulnerabilty were defined as a return period, the former being related to the first overflowing event, the latter being related to the expected level of protection. After a presentation on the Inondabilite framework, a discussion gives the advantages and limitations of such hydrological assessment of flood vulnerability. A complementary work is presented on the economical assessment of the willingness of population to pay for flood risk mitigation.Inondabilité; Vulnerabilité; Crue; Evaluation des risques; Economie; Aléa; Consentement à payer

OpenML Benchmarking Suites

Machine learning research depends on objectively interpretable, comparable, and reproducible algorithm benchmarks. Therefore, we advocate the use of curated, comprehensive suites of machine learning tasks to standardize the setup, execution, and reporting of benchmarks. We enable this through software tools that help to create and leverage these benchmarking suites. These are seamlessly integrated into the OpenML platform, and accessible through interfaces in Python, Java, and R. OpenML benchmarking suites are (a) easy to use through standardized data formats, APIs, and client libraries; (b) machine-readable, with extensive meta-information on the included datasets; and (c) allow benchmarks to be shared and reused in future studies. We also present a first, carefully curated and practical benchmarking suite for classification: the OpenML Curated Classification benchmarking suite 2018 (OpenML-CC18)