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

Projet UNIT GIMIROB : Gestion Immobilière, Maintenance, Inspection pouR les Ouvrages et les Bâtiments

Méthodes et approchesInternational audienceLe projet GIMIROB constitue un produit de formation portant sur divers aspects liés à la gestion des ouvrages de génie civil et des bâtiments. Il se situe à l'interface des besoins de connaissance des ingénieurs en construction civile qui souhaitent mieux appréhender des problématiques de gestion de patrimoine(s), et des gestionnaires de patrimoine(s) qui souhaitent mieux comprendre comment le vieillissement des matériaux et des ouvrages affectent le patrimoine. Les modules de formation de base sont pour l'instant disponibles. Ils ont été produits par un collectif de 8 établissements et une équipe de 12 personnes sur des supports multiples (pages web, fichiers pdf, présentations ou document OpenOffice) à l'aide de la chaîne éditoriale Opale-Scenari. Les supports de formation seront prochainement accessibles que le portail d'UNIT. La suite du projet consistera à étendre les modules de formation et à les rendre plus interactifs les uns avec les autres pour qu'ils participent à un support effectif de web-formation

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

Experimental and numerical investigation of the response of geocell-reinforced walls to horizontal localized impact

International audienceThe aim of this work is to study the effect of a localized impact on a wall made of soil reinforced with geocells. First, two structures were tested with an impacting remote-controlled car. Such experiments, carried out on 1/10th-scale model structures for practical reasons, are designed to mimic the mechanical response of an alveolar geocell reinforcement system. Two types of constitutive materials were considered for the geocells with very different mechanical properties. The test structures were dismantled after the tests to analyse the influence of the impact on the cell layers, especially within their bulk. Examining the video of the tests captured with two high-speed cameras also helped understanding the phenomena that occurred during impact. These experiments were completed by numerical simulations whose objective was to understand more clearly the causes of the phenomena observed either within the dismantled structures or in the videos

SNP mining in C. clementina BAC end sequences; transferability in the Citrus genus (Rutaceae), phylogenetic inferences and perspectives for genetic mapping

<p>Abstract</p> <p>Background</p> <p>With the increasing availability of EST databases and whole genome sequences, SNPs have become the most abundant and powerful polymorphic markers. However, SNP chip data generally suffers from ascertainment biases caused by the SNP discovery and selection process in which a small number of individuals are used as discovery panels. The ongoing International Citrus Genome Consortium sequencing project of the highly heterozygous Clementine and sweet orange genomes will soon result in the release of several hundred thousand SNPs. The primary goals of this study were: (i) to estimate the transferability within the genus <it>Citrus </it>of SNPs discovered from Clementine BACend sequencing (BES), (ii) to estimate bias associated with the very narrow discovery panel, and (iii) to evaluate the usefulness of the Clementine-derived SNP markers for diversity analysis and comparative mapping studies between the different cultivated <it>Citrus </it>species.</p> <p>Results</p> <p>Fifty-four accessions covering the main <it>Citrus </it>species and 52 interspecific hybrids between pummelo and Clementine were genotyped on a GoldenGate array platform using 1,457 SNPs mined from Clementine BES and 37 SNPs identified between and within <it>C. maxima, C. medica, C. reticulata </it>and <it>C. micrantha</it>. Consistent results were obtained from 622 SNP loci. Of these markers, 116 displayed incomplete transferability primarily in <it>C. medica, C. maxima </it>and wild <it>Citrus </it>species. The two primary biases associated with the SNP mining in Clementine were an overestimation of the <it>C. reticulata </it>diversity and an underestimation of the interspecific differentiation. However, the genetic stratification of the gene pool was high, with very frequent significant linkage disequilibrium. Furthermore, the shared intraspecific polymorphism and accession heterozygosity were generally enough to perform interspecific comparative genetic mapping.</p> <p>Conclusions</p> <p>A set of 622 SNP markers providing consistent results was selected. Of the markers mined from Clementine, 80.5% were successfully transferred to the whole <it>Citrus </it>gene pool. Despite the ascertainment biases in relation to the Clementine origin, the SNP data confirm the important stratification of the gene pools around <it>C. maxima, C. medica </it>and <it>C. reticulata </it>as well as previous hypothesis on the origin of secondary species. The implemented SNP marker set will be very useful for comparative genetic mapping in <it>Citrus </it>and genetic association in <it>C. reticulata</it>.</p