Analyse et contrôle de la qualité des données utilisées lors des expertises de barrages

National audienceLes données utilisées lors de l'expertise de barrages ont été structurées sous la forme d'indicateurs. Ces indicateurs sont fréquemment " imparfaits " car ils contiennent incertitude, imprécision ou incomplétude. Nous proposons une voie d'analyse et de contrôle de ces imperfections basée sur (i) l'identification et l'explicitation des sources d'imperfections sous forme de critères, (ii) la quantification des critères sur une échelle de notation, (iii) l'agrégation de ces notes par la méthode d'analyse multicritère ELECTRE TRI. Au final est obtenu un score de qualité associé à chaque indicateur. Cette représentation des imperfections a notamment pour objectif la définition d'actions correctives pour le système d'évaluation afin d'améliorer la qualité des indicateurs en réduisant les imperfections qui leur sont associées. La démarche est appliquée à un cas réel au cours d'une revue décennale / Data used during dam review were structured as indicators. These indicators are frequently imperfect as they contain uncertainty, imprecision, incompleteness. In this paper, we propose an analysis and control of these imperfections based on (i) the identification of the various sources of imperfection and their definition as criteria, (ii) the providing of a reliable way to assess these criteria and (iii) the aggregation of the values resulting from the assessment of the criteria using the multi-criteria analysis ELECTRE TRI. A quality score associated to each data is obtained at the end of the process. This imperfection representation notably aims at proposing corrective actions to improve the quality of indicators by lowering the linked imperfections. This approach was applied to a real-case study

A dam assessment support system based on physical measurements, sensory evaluations and expert judgements

In engineering system control, human beings can play various key roles, in particular concerning measurement, global assessment and decision. This paper focuses on methods that allow the representation and aggregation of heterogeneous data (sensory evaluations, physical measurements, outputs of mathematical models, etc.) used in a global dam assessment process. It is acknowledged that in such complex systems many of the variables involved are evaluated with uncertainty. We propose a possibility theory-based approach to deal with all the different uncertain pieces of information and propagate them in aggregation models for global dam assessment. Finally, decision-making and communication applications relating to dam safety are presented

Estimation de la qualité des données d'expertise des barrages

National audienceLa maîtrise des risques de rupture des barrages est d'une importance majeure dans notre société de par les enjeux associés. De plus, la pertinence des actions de maintenance ou de réparation d'un barrage dépend de la connaissance de sa performance vis-à-vis de ses principaux modes de rupture et de la fiabilité de cette connaissance. Nous nous intéressons ici à l'estimation de la fiabilité du résultat du modèle d'évaluation possibiliste de la performance des barrages, développé par le Cemagref, à partir de l'estimation de la qualité de ses données d'entrée. Ce modèle est en effet basé sur l'utilisation de données multisources hétérogènes et imparfaites (imprécises, incertaines et incomplètes). Cette communication détaille plus particulièrement les phases d'analyse et de validation des grilles d'analyse de la qualité des données et d'agrégation des critères de ces grilles de qualité. / The control of failure risks of dams is of major importance in our society as regards the associated consequences. Moreover, the relevance of maintenance or repair actions depends on the dam performance knowledge as regards their main failure modes and the reliability of this knowledge. Here, the estimation of the result reliability of the dam performance assessment model, based on evidence theory and developed by the Cemagref, will be considered. The result reliability estimation is done by the quality estimation of the input data. This performance assessment model is based on the use of multisource, heterogeneous and imperfect data (imprecise, uncertain and incomplete data). This communication is more detailing the analysis validation phases of the grids of data quality analysis and the aggregation phase of the criteria of these quality grids

Aide à la décision pour l'expertise des barrages

National audienceUn modèle d'évaluation des performances des barrages vis-à-vis de leurs principaux modes de rupture et de dégradation a été développé (Curt, 2008). Les données d'entrée (indicateurs) et de sortie (performance du barrage) de ce modèle sont des distributions de possibilité. Cette communication est axée sur la problématique de la prise de décision associée à ce résultat possibiliste : comment prioriser les actions de maintenance à entreprendre sur le barrage et comment transmettre l'information aux gestionnaires ? Nous proposons une analyse comparative des méthodes de défuzzification afin de sélectionner les méthodes répondant le mieux à cette problématique d'aide à l'expertise des barrages. / An assessment model of dam performances as regards their main failure modes and degradation modes was developed (Curt, 2008). The input data (indicators) and the ouput data (dam performance) of this model are possibility distributions. This paper focuses on the problematic of decision making associated to this possibility result: how to classify maintenance actions that have to be made on that dam and how to convey this result to dam managers? A comparative analysis of defuzzyfication methods is provided; those methods allow to best answer to this problematic of dam expertise

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

Joint analysis of environmental and risk policies: Methodology and application to the French case

International audienceFrench public authorities have to manage the protection of the environment and risks. This study proposes a method for analyzing the French law on environmental hazards and the protection of the environment in the context of land planning. The main question asked is: Do the difficulties of implementing environmental policies stem from the complexity of the law or from the organization of local land management? The final aim is to offer reading keys to aid local planning decisions in France. The approach proposed is based on collecting and organizing the regulations, analyzing their application in practice, and comparing the legal standpoints to the logic of local decision-makers. This study demonstrates the extent to which French environmental regulations are complex and how they can be adapted locally in order to improve their application and efficiency

Joint analysis of environmental and risk policies: Methodology and application to the French case

International audienceFrench public authorities have to manage the protection of the environment and risks. This study proposes a method for analyzing the French law on environmental hazards and the protection of the environment in the context of land planning. The main question asked is: Do the difficulties of implementing environmental policies stem from the complexity of the law or from the organization of local land management? The final aim is to offer reading keys to aid local planning decisions in France. The approach proposed is based on collecting and organizing the regulations, analyzing their application in practice, and comparing the legal standpoints to the logic of local decision-makers. This study demonstrates the extent to which French environmental regulations are complex and how they can be adapted locally in order to improve their application and efficiency

Assessing the environmental and social co-benefits and disbenefits of natural risk management measures

International audienceRisk management measures (RMM) participate in the sustainability of cities and communities through the protection of these socio-eco-environmental systems against threatening events, and by ensuring system recovery. They include structural measures that are grey or green/blue solutions, or hybrid solutions combining the two former types. These measures can provide environmental and social co-benefits (e.g., improved biodiversity, recreational services) and disbenefits (e.g., the development of unwanted flora, concentrations of pollutants). The aim of this article is to provide an approach to assess and compare RMMs by considering these different dimensions. An application to three natural hazards-floods, coastal floods and wildfiresis proposed. The approach takes the form of a procedure to assess the co-benefits/disbenefits of the various RMMs and some technical specifications. It allows comparing the performances of one RMM against another and collectively discussing the choice of RMMs that takes into account a wide range of dimensions. The approach is based on the formulation of eight sustainability criteria and thirty-one indicators. The results were graphically displayed as several types of diagram: one radar chart per RMM, compiling all the indicators; one radar chart by type of risk studied (flood, wildfire and coastal flooding) based on averages of indicators per criterion; a table of the global score assigned to each RMM calculated with an arithmetic mean or a weighted mean. The approach relies on an interdisciplinary research team and involves end-users in a focus group for the validation step. This approach constitutes a transparent base for decisionmaking processes in the context of sustainable spatial planning against natural risks