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[Departement_IRSTEA]Eaux [TR1_IRSTEA]ARCEAU [ADD1_IRSTEA]Hydrosystèmes et risques naturels; International audience; The Rhône river basin is a highly populated area in southeastern France, with a high concentration of alpine glaciers which have been rapidly retreating in the last decades as the climate warms. In order to anticipate potential issues and conflicts concerning water resources in the high alpine valleys, there is a strong need for local-to-regional projections of glacier and snow hydrological contributions. In this study, we present ALPGM (ALpine Parameterized Glacier Model), a fully parameterized glacier model, which makes use of the most recent available data and reanalysis to simulate the evolution of all the ~660 glaciers in the French Alps for the 1984-2100 period. It computes glacier-wide yearly surface mass balances (SMB) using machine learning, and it updates the glacier geometry by redistributing the glacier-wide SMB values along the glacier elevations according to a glacier-specific parameterized function.

The positioning of connected objects has become a major enabling feature for a variety of applications and services in the Internet of Things (IoT) domain. To avoid prohibitive power consumption and hardware complexity at the IoT nodes to be localized, one alternative to the conventional Global Positioning System (GPS) consists in making opportunistic use of location-dependent radio metrics, out of the sensor data packets that may be transmitted from these end-devices to their serving gateways.In this thesis, we focus on the Received Signal Strength Indicator (RSSI) radio metrics, which are available by default in Long Range (LoRa) low data rate transmissions, while targeting fingerprinting-based localization for the final application. So as to accurately position LoRa nodes at the city scale through fingerprinting, one first needs to build an accurate prior RSSI map of the radio environment (offline), typically based on a few real field measurements. This prior radio map is subsequently used as a reference (for comparison) during the online localization phase. One main goal of this work is hence to obtain an exhaustive and accurate prior map, given sparse and non-uniformly distributed RSSI measurements, while applying advanced machine learning approaches.Firstly, we discuss the main general challenges of the map reconstruction itself, in light of our specific fingerprinting-based localization context. In particular, by means of theoretical bounds characterizing the best RSSI-based positioning accuracy in case of both fingerprinting (i.e., considering a prior radio map) or parametric positioning (i.e., considering a link-wise range-dependent power path loss model), we illustrate and discuss the impact of RSSI dynamics as a function of space with respect to the final positioning performance. Further, we also describe and analyze the experimental datasets used in our study, including a dataset related to the Grenoble city area, which is still under extension, while devising metrological and pre-processing aspects. These experimental data have been exploited to feed both the underlying radio models with realistic parameters, as well as the learning algorithms used for map reconstruction with realistic inputs.Secondly, we briefly recall the main ideas behind supervised and semi-supervised learning approaches, their main working assumptions, as well as their classical models. In particular, we present a Neural Architecture Search (NAS) approach, which is a recent technique allowing to automatically find a Neural Network (NN) model with an optimized architecture suited to a given problem.We then cover a first application of this NAS to the RSSI map reconstruction problem, in combination with data augmentation techniques, where only a limited amount of labeled input data is available for learning.Finally, taking also advantage from having access to side (meta-)information about the local area (e.g., city layout, terrain elevation, gateway location, etc...), we solve out the generalization problem for each city (typically, over gateways). The NAS algorithm is then applied again to find the NN model with the best architecture for each of the supposed settings, depending on the amount of such prior side information. On this occasion, we show for instance that using additional views improves the final accuracy of the RSSI map reconstruction, especially in sub-areas close to the gateways where larger variations of the average received signal power are usually ob- served (ultimately, with a prominent beneficial impact onto positioning performance accordingly).; La détermination de la position d'objets connectés est devenue une fonctionnalité majeure pour une variété d'applications et de services dans le domaine de l'Internet des objets (IoT). Afin d'éviter une consommation d'énergie prohibitive et une complexité matérielle importante au niveau des nœuds IoT à localiser, une alternative au système conventionnel de positionnement global par satellites (GPS) consiste à faire usage, de manière opportuniste, de métriques radio dépendantes de la position, en s'appuyant en particulier sur les paquets de données qui peuvent être transmis par ces mêmes noeuds-capteurs à leurs stations de base de rattachement. Dans cette thèse, nous nous concentrons sur la puissance moyenne reçue, ou RSSI (Received Signal Strength Indicator), qui est une métrique disponible par défaut dans le cadre de communications à longue portée et à faible débit de données de type LoRa (Long Range), tout en ciblant une localisation basée sur la reconnaissance de signatures radio, ou fingerprinting, en termes d'application finale. Afin de positionner avec précision les nœuds LoRa à l'échelle d'une ville grâce via ces techniques de fingerprinting, il est nécessaire d'établir préalablement une carte RSSI suffisamment précise de l'environnement radio (hors ligne), généralement à partir de quelques mesures réelles collectées sur le terrain. Cette carte radio préalable est ensuite utilisée comme référence (pour comparaison) pendant la phase de localisation temps-réel (en ligne). L'objectif principal de ce travail est donc d'obtenir une carte préalable exhaustive et précise, à partir de mesures RSSI éparses et non-uniformément distribuées, en appliquant des approches avancées d'apprentissage automatique. Tout d'abord, nous discutons des principaux défis inhérents à la reconstruction de la carte radio elle-même, à la lumière de notre application spécifique de localisation. En particulier, à l'aide de limites théoriques caractérisant la meilleure précision de positionnement atteignable à partir de mesures RSSI dans le cas du fingerprinting (c.-à-d., en considérant une carte radio préalable) ou d'un positionnement paramétrique (c.-à-d., en considérant un modèle d'atténuation au niveau d'un lien radio, en fonction de la distance entre émetteur et récepteur), nous illustrons et discutons l'impact de la dynamique spatiale du RSSI (c.-à-d., en fonction de l'espace 2D) sur les performances finales de positionnement. En outre, nous décrivons et analysons les jeux de données expérimentales utilisés dans le cadre de notre étude, dont un jeu relatif à la zone urbaine de Grenoble, qui est actuellement encore en cours d'extension, tout en revenant sur quelques aspects métrologiques, ainsi que sur les premiers post-traitements appliqués. Ces données expérimentales ont été exploitées pour alimenter à la fois les modèles radio sous-jacents (avec des paramètres réalistes) et les algorithmes de reconstruction de cartes (avec des données d'entrée réalistes pour les étapes d'apprentissage, de validation et de test).Dans un deuxième temps, nous rappelons brièvement les principales idées qui sous-tendent les approches d'apprentissage supervisé et semi-supervisé, leurs principales hypothèses de travail, ainsi que leurs modèles classiques. En particulier, nous présentons une technique récente dite de Neural Architecture Search (NAS), qui permet de trouver automatiquement un modèle de réseau neuronal (NN) avec une architecture optimisée, adaptée à un problème donné.Nous appliquons ensuite ce NAS à notre problème spécifique de reconstruction de cartes RSSI, en combinaison avec des techniques d'augmentation de données, pour lesquelles seule une quantité limitée de données étiquetées en entrée est nécessaire pour réaliser l'apprentissage.Enfin, en tirant également profit de l'accès à des (méta-)informations secondaires concernant la zone locale de travail (par exemple, le plan de la ville, l'élévation du terrain, l'emplacement des stations de base, etc...), nous résolvons un problème de généralisation (c.-à-d., entre stations de base "apprises" et "non-apprises") pour chacune des villes testées. L'algorithme NAS est ensuite appliqué à nouveau afin de trouver le modèle NN présentant la meilleure architecture, en fonction de la quantité d'information secondaire disponible. A cette occasion, nous montrons par exemple que l'utilisation de vues supplémentaires en complément des mesures de puissance améliore la précision finale de la reconstruction de la carte RSSI, en particulier dans les sous-zones proches des stations de base, où des variations plus importantes de la puissance moyenne du signal reçu sont généralement observées (avec, en fin de compte, un impact positif présumément plus important en termes de performances de positionnement).

Coastal areas are highly diverse, ecologically rich, regions of key socio-economic activity, and are particularly sensitive to sea- level change. Over most of the 20th century, global mean sea level has risen mainly due to warming and subsequent expansion of the upper ocean layers and the melting of glaciers and ice caps. Over the last three decades, increased mass loss of the Greenland and Antarctic ice sheets has also started to contribute significantly to contemporary sea-level rise. The future mass loss of these ice sheets, which combined represent a sea-level rise potential of ~65 m, constitutes the main source of uncertainty in long-term (centennial to millennial) sea-level rise projections. Improved knowledge of the magnitude and rate of future sea-level change is therefore of utmost importance. Moreover, sea level does not change uniformly across the globe, and can differ greatly at both regional and local scales. The most appropriate and feasible sea level mitigation and adaptation measures in coastal regions strongly depend on local land use and associated risk aversion. Here, we advocate that addressing the problem of future sea-level rise and its impacts requires (i) bringing together a transdisciplinary scientific community, from climate and cryospheric scientists to coastal impact specialists, and (ii) interacting closely and iteratively with users and local stakeholders to co-design and co-build coastal climate services, including addressing the high-end risks. Following these principles, as also adopted in the EU project “Projecting sea-level rise: from projections to local implications” (PROTECT), we encourage the formation of research consortia that cover the entire knowledge chain. In this way global sea-level science can be linked to effective coastal climate services at the scale of risk and adaptation

The current trend in electric autonomous vehicles design is based on pre-existing models of cities which have been built for cars. The carbon footprint of cities cannot be reduced until the overall requirement for vehicles is reduced and more green and pedestrianized zones are created for better livability. However, such green zones cannot be scaled without providing autonomous mobility solutions, accessible to people with reduced mobility. Such solutions need to be capable of operating in spaces shared with pedestrians, which makes this a much harder problem to solve as compared to traditional autonomous driving. This thesis serves as a starting point to develop such autonomous mobility solutions. The work is focused on developing a navigation system for autonomous vehicles operating around pedestrians. The suggested solution is a proactive framework capable of anticipating pedestrian reactions and exploiting their cooperation to optimize the performance while ensuring pedestrians safety and comfort.A cooperation-based model for pedestrian behaviors around a vehicle is proposed. The model starts by evaluating the pedestrian tendency to cooperate with the vehicle by a time-varying factor. This factor is then used in combination with the space measurements to predict the future trajectory. The model is based on social rules and cognitive studies by using the concept of the social zones and then applying the deformable virtual zone concept (DVZ) to measure the resulting influence in each zone. Both parts of the model are learnt using a data-set of pedestrians to vehicle interactions by manually annotating the behaviors in the data-set.Moreover, the model is exploited in the navigation system to control both the velocity and the local steering of the vehicle. Firstly, the longitudinal velocity is proactively controlled. Two criteria are considered to control the longitudinal velocity. The first is a safety criterion using the minimum distance between an agent and the vehicle’s body. The second is proactive criterion using the cooperation measure of the surrounding agents. The latter is essential to exploit any cooperative behavior and avoid the freezing of the vehicle in dense scenarios. Finally, the optimal control is derived using the gradient of a cost function combining the two previous criteria. This is possible thanks to a suggested formulation of the cooperation model using a non-central chi distribution for the distance between the vehicle and an agent.A smooth steering is derived using a proactive dynamic channel method for the space exploration. The method depends on evaluating the navigation cost in a channel (sub-space) using a fuzzy cost model. The channel with the minimum cost is selected, and a human-like steering is affected using a Quintic spline candidate path between channels. Finally, the local steering is derived using a sliding mode path follower.The navigation is evaluated using PedSim simulator under ROS in pedestrian-vehicle interaction scenarios. The navigation is tested with different pedestrian density and sparsity. The proactive framework managed to navigate the vehicle producing smooth trajectories while maintaining the pedestrians’ safety and reducing the travel time in comparison with traditional reactive methods (Risk-RRT).; La tendance actuelle dans la conception des véhicules électriques autonomes est basée sur des modèles préexistants de villes qui ont été construits pour les voitures. L'empreinte carbone des villes ne peut être réduite tant que les besoins globaux en véhicules ne sont pas réduits et que davantage de zones vertes ne soient créées pour une meilleure habitabilité. Cependant, Le nombre de ces zones ne peuvent être augmentées sans fournir des solutions de mobilité autonomes et accessibles à tous. De telles solutions doivent être capables de fonctionner dans des espaces partagés avec les piétons, ce qui rend ce problème beaucoup plus difficile par rapport à la conduite autonome traditionnelle. Comme point de départ pour développer de telles solutions, cette thèse pose des jalons pour développer de telles solutions et se focalise sur la navigation pour les véhicules autonomes à proximité des piétons. La solution proposée est un cadre proactif capable d'anticiper les réactions des piétons et d'exploiter leur coopération pour optimiser la performance tout en assurant leur sécurité.Dans un premier temps, un modèle de comportement des piétons est proposé. Le modèle commence par évaluer la tendance des piétons à coopérer avec le véhicule par un paramètre dépendant du temps. Cette tendance est ensuite utilisée combinée à des mesures spatiales pour prédire la trajectoire future. Le modèle est basé sur des règles sociales et des études cognitives en utilisant le concept de zones sociales. Il intègre ensuite le concept de zone virtuelle déformable (ZVD) pour mesurer l'influence résultante dans chaque zone. Les deux parties du modèle sont entrainées grâce à un corpus de données vidéos annoté où des piétons interagissent avec un véhicule.Dans un second temps, La vitesse et les manœuvres du véhicule sont étudiées. Premièrement, deux critères sont considérés pour contrôler la vitesse longitudinale. Le premier est un critère de sécurité qui utilise la distance minimale entre un agent et le châssis du véhicule. Le second est un critère proactif qui utilise la mesure de coopération des agents environnants. Ce dernier est indispensable pour exploiter tout comportement coopératif et éviter le gel du véhicule dans des scénarios denses. Enfin, le contrôle optimal est dérivé en utilisant le gradient d'une fonction de coût combinant les deux critères précédents. Ceci est possible grâce à une formulation suggérée du modèle de coopération utilisant une distribution Chi non centrale pour la distance entre le véhicule et un agent.Un cadre de canaux dynamiques et proactifs est suggéré pour la manœuvre locale. La méthode dépend de l'évaluation du coût de navigation dans un canal (sous-espace) à l'aide d'un modèle de coût flou. Le canal avec le moindre coût est sélectionné et une transition douce est réalisée à l'aide d'une spline Quintique entre les canaux. Enfin, la control local est calculé à l'aide d'un contrôleur de mode glissant.La navigation est évaluée à l'aide du simulateur PedSim sous ROS dans des scénarios d'interaction piéton-véhicule. La navigation est testée avec différentes densités et parcimonie de piétons. Le cadre proactif a produit des trajectoires de véhicules fluides tout en maintenant la sécurité des piétons et en réduisant le temps de trajet par rapport aux méthodes réactives traditionnelles (Risk-RRT).

We present here the results obtained during an intensive field campaign conducted in the framework of the French “BIO-MAÏDO” (Bio-physico-chemistry of tropical clouds at Maïdo (Réunion Island): processes and impacts on secondary organic aerosols’ formation) project. This study integrates an exhaustive chemical and microphysical characterization of cloud water obtained in March–April 2019 at Reunion Island (Indian Ocean). Fourteen cloud samples have been collected along the slope of this mountainous island. A comprehensive chemical characterization of these samples is performed, including inorganic ions, metals, oxidants, and organic matter (organic acids, sugars, amino acids, carbonyls, and low-soluble volatile organic compounds (VOCs)). Cloud water presents high molecular complexity with elevated water-soluble organic matter content partly modulated by microphysical cloud properties. As expected, our findings show the presence of compounds of marine origin in cloud water samples (e.g., chloride, sodium) demonstrating ocean–cloud exchanges. However, the non-sea salt fraction of sulphate varies between 38 and 91 %, indicating the presence of other sources. Also, the presence of amino acids and for the first time in cloud waters of sugars, clearly indicates that biological activities contribute to the cloud water chemical composition. A significant variability between events is observed in the dissolved organic content (25.5 ± 18.4 mgC L−1), with levels reaching up to 62 mgC L−1. This variability was not similar for all the measured compounds, suggesting the presence of dissimilar emission sources or production mechanisms. For that, a statistical analysis is performed based on back-trajectory calculations using the CAT (Computing Atmospheric Trajectory Tool) model associated with land cover registry. These investigations reveal that air mass origins and microphysical variables do not fully explain the variability observed in cloud chemical composition, highlighting the complexity of emission sources, multiphasic transfer, and chemical processing in clouds. Additionally, several VOCs (oxygenated and low-soluble VOCs) were analysed in both gas and aqueous phases. Significant levels of biogenic low-soluble VOCs were detected in the aqueous phase, indicating the cloud-terrestrial vegetation exchange. Cloud scavenging of VOCs is assessed and compared to Henry’s law equilibrium to evaluate potential super or sub saturation conditions. The evaluation reveals the supersaturation of low-soluble VOCs from both natural and anthropogenic sources. Our results depict even higher supersaturation of terpenoids, suggesting their importance in the aqueous phase chemistry in highly impacted tropical areas.

International audience

International audience; In a context of densification of urban centers and climate change, coastal megacities in emerging countries have to face new issues about water management. With more than 9 million inhabitants, Ho Chi Minh City (HCMC), the economic capital of Vietnam, is in full demographic and economic expansion. The city does not have water treatment networks that meet the urgent needs. Indeed, in 2020, less than 15% of the population is connected to a sewerage network and treatment plant. The deterioration of water quality of Saigon River crossing the city is dramatic. Ho Chi Minh City authorities therefore plan to build new sanitation networks and ten wastewater treatment plants (WWTPs) over the next fifteen years, drawing inspiration from the centralized water management models of industrialized countries. However, the question arises of the relevance of this extremely expensive choice and not necessarily adapted to the particular conditions of this megacity in tropical monsoon zone and under the influence of tidal cycles. Using the estuarine biogeochemical model (C-GEM), this study aims at assessing the water quality of the Saigon River (oxygen depletion, nutrients concentration) in response to three scenarios of HCMC development (population growth and new water management infrastructures). In addition, projected new climatic conditions (temperature, hydrology) will be considered. The results of three scenarios show that the construction of new WWTPs is relevant. However, the rapid population growth in HCMC will make improvements support by WWTPs not sufficient to turn the water quality in Saigon River from a state of bad quality to good as expected.

Tesis Doctoral.-- Doctoral programme of Physics.-- Doctor by the Université Grenoble Alpes and the Universitat de les Illes Balears., Sea Surface Height (SSH) observations describing scales in the range 10 - 100 km are crucial to betterunderstand energy transfers across scales in the open ocean and to quantify vertical exchanges of heatand biogeochemical tracers. The Surface Water Ocean Topography (SWOT) mission is a new wide-swathaltimetric satellite which is planned to be launched in 2022. SWOT will provide information on SSH at akilometric resolution, but uncertainties due to various sources of errors will challenge our capacity to extractthe physical signal of structures below a few tens of kilometers. Filtering SWOT noise and errors is a keystep towards an optimal interpretation of the data.The aim of this study is to explore image de-noising techniques to assess the capabilities of the future SWOTdata to resolve the oceanic fine scales. Pseudo-SWOT data are generated with the SWOT simulator forOcean Science, which uses as input the SSH outputs from high-resolution Ocean General Circulation Models(OGCMs). Several de-noising techniques are tested, to find the one that renders the most accurate SSHand its derivatives fields while preserving the magnitude and shape of the oceanic features present. Thetechniques are evaluated based on the root mean square error, spectra and other diagnostics.In Chapter 3, the pseudo-SWOT data for the Science phase is analyzed to assess the capabilities of SWOT toresolve the meso- and submesoscale in the western Mediterranean. A Laplacian diffusion de-noising techniqueis implemented allowing to recover SSH, geostrophic velocity and relative vorticity down to 40 - 60 km. Thisfirst step allowed to adequately observe the mesoscale, but space is left for improvement at the submesoscale,specially in better preserving the intensity of the SSH signal.In Chapter 4, another de-noising technique is explored and implemented in the same region for the satellite’sfast-sampling phase. This technique is motivated by recent advances in data assimilation techniques to removespatially correlated errors based on SSH and its derivatives. It aims at retrieving accurate SSH derivatives,by recovering their structure and preserving their magnitude. A variational method is implemented whichcan penalize the SSH derivatives of first, second, third order or a combination of them. We find that thebest parameterization is based on a second order penalization, and find the optimal parameters of this setup.Thanks to this technique the wavelengths resolved by SWOT in this region are reduced by a factor of 2,whilst preserving the magnitude of the SSH fields and its derivatives., In Chapter 5, we investigate the finest spatial scale that SWOT could resolve after de-noising in severalregions, seasons and using different OGCMs. Although a method is found to mitigate the impact of SWOTinstrumental noise and errors, large uncertainties remain due to the incomplete understanding of the impactof fast unbalanced motions (e.g. internal gravity waves) on SSH signals, and therefore the impact on theperformance of the de-noising algorithm. Our study focuses on different regions and seasons in order todocument the variety of regimes that SWOT will sample. The de-noising algorithm performs well even inthe presence of intense unbalanced motions, and it systematically reduces the smallest resolvable wavelength.Advanced de-noising algorithms also allow to reliably reconstruct SSH gradients (related to geostrophicvelocities) and second order derivatives (related to geostrophic vorticity). Our results also show that asignificant uncertainty remains about SWOT’s finest resolved scale in a given region and season because ofthe large spread in the level of variance predicted among our high-resolution ocean model simulations.The de-noising technique developed, implemented and tested in this doctoral thesis allows to recover, insome cases, SWOT spatial scales as low as 15 km. This method is a very useful contribution to achieving theobjectives of the SWOT mission. The results found will help better understand the ocean’s dynamics andoceanic features and their role in the climate system., I would like to acknowledge CNES and FP7 funding, which made possible this PhD. Also, I would like toacknowledge other sources of funding that allowed me to carry out different activities during my PhD: thePre-SWOT project and COST Action ES140.

The upcoming Surface Water Ocean Topography (SWOT) satellite altimetry mission is expected to yield two-dimensional high-resolution measurements of Sea Surface Height (SSH), thus allowing for a better characterization of the mesoscale and submesoscale eddy field. However, to fulfill the promises of this mission, filtering the tidal component of the SSH measurements is necessary. This challenging problem is crucial since the posterior studies done by physical oceanographers using SWOT data will depend heavily on the selected filtering schemes. In this paper, we cast this problem into a supervised learning framework and propose the use of convolutional neural networks (ConvNets) to estimate fields free of internal tide signals. Numerical experiments based on an advanced North Atlantic simulation of the ocean circulation (eNATL60) show that our ConvNet considerably reduces the imprint of the internal waves in SSH data even in regions unseen by the neural network. We also investigate the relevance of considering additional data from other sea surface variables such as sea surface temperature (SST)., Accepted for publication in IEEE IGARSS 2020 conference

The work in this thesis falls in the category of comprehending dynamical systems relatedto thin liquid films driven by gravity; mainly shallow water models and lubrication equations.From a modeling point of view, we have derived from one hand 3-equation shallow water modelsfor Newtonian fluids with constant viscosity that describe the evolution of the fluid’s height, velocityand a new defined variable equivalent to the shear rate. Such models succeed in capturingunstable regimes and in giving satisfactory numerical results for the instability threshold andthe wave speed at moderate distance from threshold. On the other hand, a lubrication equationand a shallow water model were derived for a non Newtonian fluid- known as a bi-viscousfluid- whose rheology approximates that of pseudo plastic and Bingham fluids. Concerning theanalysis part, the global existence of nonnegative weak solutions for lubrication equations, suchas the Derrida-Lebowitz-Speer-Spohn equation, is proved starting from nonnegative weak solutionsfor appropriate viscous shallow-water equations (playing with drag terms and capillarityformula). The novelty in this work is to show that the BF entropy which is introduced forlubrication equations in the context of thin films is encoded inside the BD entropy introducedfor compressible Navier Stokes equations with density dependent viscosity. We also investigatethe dissipative solution of Navier Stokes system of Oldroyd-B rheology, as well as the globalweak solution for degenerate lake system of Bingham rheology.; Cette thèse porte sur la compréhension de systèmes dynamiques liés aux films liquides mincesentraînés par la gravité; principalement des modèles d’eau peu profonde et des équations delubrification. D’un point de vue modélisation, nous avons obtenu d’une part des modèles à 3équations des eaux peu profondes pour les fluides newtoniens à viscosité constante décrivantl’évolution de la hauteur du fluide, de sa vitesse et d’une nouvelle variable définie équivalenteau taux de cisaillement. De tels modèles parviennent à capturer des régimes instables et àdonner des résultats numériques satisfaisants pour l’étude de seuil d’instabilité et de la phasede l’onde à une distance modérée du seuil. D’autre part, une équation de lubrification et unmodèle d’eau peu profonde ont été obtenu à partir d’un modèle de fluide non-Newtonien connusous le nom de fluide bi-visqueux- dont la rhéologie se rapproche de celle des fluides pseudoplastiqueset de Bingham. Concernant la partie analyse, l’existence globale de solutions faiblesnon négatives pour les équations de lubrification, telles que l’équation de Derrida-Lebowitz-Speer-Spohn, partant des solutions faibles non négatives pour les équations appropriées d’eaupeu profonde visqueuse (en manipulant les termes de traînée et la formule de capillarité), estmontrée. La nouveauté dans ce travail est de montrer que l’entropie BF qui a été introduitepour les équations de lubrification dans le contexte des films minces est encodée dans l’entropieBD introduite pour Navier-Stokes compressible avec viscosités dépendant de la densité. Ons’intéresse également aux solutions dissipatives pour des systèmes incompressible et compressiblede type Oldroyd ainsi qu’aux solutions faibles pour un système dégénéré de type Bingham.

SUMMARYIn late June 2016, the Harmalière clayey landslide (located 30 km south of the city of Grenoble, French Alps) was dramatically reactivated at the headscarp after a 35-yr-long period of continuous but limited activity. The total involved volume, which moved as sliding blocks of various sizes, was estimated to be about 2 × 10 6 m3. Two seismometers were installed at the rear of the main headscarp in August 2016, on both sides of a developing fracture delineating a block with a volume of a few hundred cubic metres. For 4 months, they continuously recorded seismic ambient vibrations and microearthquakes until the block broke. Five seismic parameters were derived from the monitoring: the cumulative number of microearthquakes (CNe), the seismic energy (SE), the block resonance frequency (fB), the relative variation in Rayleigh wave velocity (dV/V) deduced from noise cross-correlations between the two sensors and the associated correlation coefficient (CC). All parameters showed a significant precursory signal before the rupture, but at very different times, which indicates the complexity of the rupture mechanism in this clay material.

International audience; Dendrogeomorphic analyses provide long and continuous chronologies of mass movements that are useful for the detection of trends related to climate change. Socio-environmental changes can, however, induce non-stationarities. This study addresses the following questions: (1) How does the evolution of forest cover induce non-stationarities in tree-ring based reconstructions of snow avalanche activity? (2) How are trends inherent to tree-ring approaches distinguishable from real fluctuations in avalanche activity? Using dendrogeomorphic techniques, we reconstructed snow avalanches in six adjacent paths in the French Alps. Results show two distinct trends in process activity between 1750 and 2016. In the southern paths, the frequency of snow avalanches increased sharply in the 1970s. The distribution of tree ages, as well as old topographic maps, allow an attribution of this trend to the destruction of large parts of the forest stand by a large snow avalanche in the 1910-20 s. This extreme event induced a sudden change in the capability of newly colonizing trees to record subsequent snow avalanches. In the northern paths, by contrast, progressive afforestation starting in the mid-19th century, as well as colonization of the release areas after World War II, resulted in a strong reduction in snow avalanche activity since the 1930s. Even if global warming remains a possible additional driver of snow avalanche activity at the study sites, the rural exodus and the abatement of pastoral practices during the 19th and 20th centuries are the main explanations for the observed trends in process activity. Results also illustrate a need to clarify the complex interrelations among forest evolution, global warming, social practices, and the process activity itself when interpreting trends in mass movements. (C) 2020 Elsevier Ltd. All rights reserved

OZCAR-RI, the French Critical Zone Research Infrastructure gathers 20 observatories sampling various compartments of the Critical Zone, and having historically developed their own data management and distribution systems. However, these efforts have generally been conducted independently. This has led to a very heterogeneous situation, with different levels of development and maturity of the systems and a general lack of visibility of data from the entire OZCAR-RI community. To overcome this difficulty, a common Information System (Theia/OZCAR IS) was built to make these in situ observation FAIR (Findable, Accessible, Interoperable, Reusable). The IS will allow the data to be visible in the European eLTER-RI (European Long Term Ecosystem Research) Research Infrastructure to which OZCAR-RI contributes.The IS architecture was designed after consultation of the users, data producers and IT teams involved in data management. A common data model including all the requested information and based on several metadata standards was defined to set up information fluxes between observatories IS and the Theia/OZCAR IS. Controlled vocabularies were defined to develop a data discovery web portal offering a faceted search with various criteria, including variables names and categories that were harmonized in a thesaurus published on the web. The communication will describe the IS architecture, the pivot data model and open source solutions used to implement the data portal that allows data discovery. The communication will also present future steps to implement data downloading and interoperability services that will allow a full implementation of these FAIR principles.

The work in this thesis falls in the category of comprehending dynamical systems relatedto thin liquid films driven by gravity; mainly shallow water models and lubrication equations.From a modeling point of view, we have derived from one hand 3-equation shallow water modelsfor Newtonian fluids with constant viscosity that describe the evolution of the fluid’s height, velocityand a new defined variable equivalent to the shear rate. Such models succeed in capturingunstable regimes and in giving satisfactory numerical results for the instability threshold andthe wave speed at moderate distance from threshold. On the other hand, a lubrication equationand a shallow water model were derived for a non Newtonian fluid- known as a bi-viscousfluid- whose rheology approximates that of pseudo plastic and Bingham fluids. Concerning theanalysis part, the global existence of nonnegative weak solutions for lubrication equations, suchas the Derrida-Lebowitz-Speer-Spohn equation, is proved starting from nonnegative weak solutionsfor appropriate viscous shallow-water equations (playing with drag terms and capillarityformula). The novelty in this work is to show that the BF entropy which is introduced forlubrication equations in the context of thin films is encoded inside the BD entropy introducedfor compressible Navier Stokes equations with density dependent viscosity. We also investigatethe dissipative solution of Navier Stokes system of Oldroyd-B rheology, as well as the globalweak solution for degenerate lake system of Bingham rheology., Cette thèse porte sur la compréhension de systèmes dynamiques liés aux films liquides mincesentraînés par la gravité; principalement des modèles d’eau peu profonde et des équations delubrification. D’un point de vue modélisation, nous avons obtenu d’une part des modèles à 3équations des eaux peu profondes pour les fluides newtoniens à viscosité constante décrivantl’évolution de la hauteur du fluide, de sa vitesse et d’une nouvelle variable définie équivalenteau taux de cisaillement. De tels modèles parviennent à capturer des régimes instables et àdonner des résultats numériques satisfaisants pour l’étude de seuil d’instabilité et de la phasede l’onde à une distance modérée du seuil. D’autre part, une équation de lubrification et unmodèle d’eau peu profonde ont été obtenu à partir d’un modèle de fluide non-Newtonien connusous le nom de fluide bi-visqueux- dont la rhéologie se rapproche de celle des fluides pseudoplastiqueset de Bingham. Concernant la partie analyse, l’existence globale de solutions faiblesnon négatives pour les équations de lubrification, telles que l’équation de Derrida-Lebowitz-Speer-Spohn, partant des solutions faibles non négatives pour les équations appropriées d’eaupeu profonde visqueuse (en manipulant les termes de traînée et la formule de capillarité), estmontrée. La nouveauté dans ce travail est de montrer que l’entropie BF qui a été introduitepour les équations de lubrification dans le contexte des films minces est encodée dans l’entropieBD introduite pour Navier-Stokes compressible avec viscosités dépendant de la densité. Ons’intéresse également aux solutions dissipatives pour des systèmes incompressible et compressiblede type Oldroyd ainsi qu’aux solutions faibles pour un système dégénéré de type Bingham.

Legged robots have a huge potential field of application that ranges from routine and dangerous works, to help in the treatment of children with autism. Nevertheless, employing these complex machines on a real application requires safety guarantees on their functioning. This is traditionally approached by over-sizing the robot design, but, since how resources should be distributed is unknown, these robots are still quite restricted in their capabilities, yet without formal safety guarantees and too expensive for most simple tasks. A quantitative analysis to determine how fast and precise, and therefore how expensive should sensors, actuators and computers be has never been investigated in the existing scientific literature. There is a long theoretical and practical work to be done in this regard and it is the goal of this thesis to initiate this discussion.Based on concepts from robust control theory, considering bounded uncertainties, we propose to quantify the effect of main sources of uncertainty on the balance control of the center of mass of the robot, since it is unstable and fundamental to develop any other task. As a first result, we established conditions to ensure the safe balance of the robot. Then, we provided control choices to reduce the restrictiveness on the motion of the robot and its cost.; Les robots à pattes ont un énorme champ d’applications potentiel, allant des travaux routiniers et dangereux, à l’assistance comme intermédiaires rassurants entre des enfants autistes et leur entourage. Cependant, l’utilisation de ces machines complexes requiert des garanties de sécurité sur leur fonctionnement. Ceci est traditionnellement abordé en sur-dimensionnant la conception du robot. Toutefois, comme la répartition des ressources est inconnue, leurs capacités sont encore assez limitées, sans garanties de sécurité formelles et trop coûteux pour la plupart des tâches simples. Une analyse quantitative visant à déterminer la rapidité et la précision, et donc le coût, des capteurs, des actionneurs et des calculateurs n’a jamais été étudiée dans la littérature scientifique existante. Il y a là tout un travail théorique et pratique qui reste à réaliser et le but de cette thèse est d'initier cette discussion.Sur la base des concepts de la théorie du contrôle robuste, prenant en compte des incertitudes bornées, nous proposons de quantifier l’effet des principales sources d’incertitude sur le contrôle de l'équilibre du centre de gravité du robot, car il est instable et fondamental pour développer toute autre tâche. Comme premier résultat, nous avons déterminé les conditions nécessaires pour assurer l'équilibre du robot en toute sécurité. Ensuite, nous fournissons des choix de contrôle pour réduire le caractère restrictif du mouvement du robot et de son cout.

This thesis work deals with the problems of joint scheduling for maintenance operations and missions for industrial vehicle fleets. The aim is to develop a methodology to adapt the joint scheduling of maintenance and missions according to the vehicles health state but also according to the missions features. These features correspond to the conditions of usage severity that have a significant impact on the truck deterioration and must be taken into account to adapt at best the maintenance operations schedule according to the deterioration evolution. The implementation of a decision support methodology to manage a fleet would improve productivity and reduce the maintenance costs while making the most of the fleet capacity. However, the joint scheduling problem for a fleet is a complex problem to solve and three main dimensions has to be considered. The first one is to jointly schedule missions and maintenance operations in a static case. The second one is to integrate the available monitoring information and the different events that can occur to update the schedule and treat the problem in a dynamic way. The third dimension is the fleet dimension that involves managing several vehicles in parallel. The first step is to jointly schedule the maintenance activity and the missions for a truck in a static case. It is assumed that all the missions to be performed are known and that no monitoring information is available. To do this, a vehicle deterioration model is defined to estimate its remaining useful lifetime to make decisions. It is a model with varying parameters since the vehicle operates under different conditions of usage severity according to the missions. It is the central point for setting up a scheduling algorithm to avoid any excessive risk of failure. The scheduling process is naturally optimized according to a criterion based on either the maintenance costs or the operating incomes. Once this methodology has been defined, it must be completed to include information on the vehicle deterioration, failure occurrences and new missions that may be requested. A dynamic approach has then been developed to solve the scheduling problem for a vehicle. If a breakdown occurs, the schedule must be updated because it is no longer adapted to the evolution of the current vehicle deterioration. Likewise, when a new mission is available, an update is essential because the priority order of the missions, defined by their deadlines, must be considered as soon as possible to avoid delay penalties. On the other hand, deterioration information can have a varying influence on the current schedule. Then, the schedule robustness has to be studied to avoid changing the mission order and the maintenance dates too often. The last step is to integrate the fleet dimension in the decision-making process. It is no longer just a question of mission order and timing for maintenance operations, but also of deciding which vehicle is assigned to which mission. The decision-making process then depends on the whole fleet. An analysis of the impact of considering the fleet dimension in the static case and then in the dynamic case is led. Simulation results are used to illustrate the developed methods and aim at showing their interest and the cost savings they generate., Ces travaux de thèse traitent des problèmes de planification conjointe des opérations de maintenance et des missions pour des flottes de véhicules industriels. Le but est de développer une méthodologie permettant d’adapter la plan- ification conjointe des maintenances et des missions en fonction de l’état de santé des véhicules mais également en fonction des caractéristiques des missions. Ces caractéristiques correspondent aux conditions de sévérité d’usage qui ont un impact important sur la dégradation du camion et doivent être prise en compte pour adapter au mieux la planification des opérations de maintenance en fonction de l’évolution de la dégradation. La mise en place d’une méthodologie d’aide à la décision pour gérer une flotte permettrait d’améliorer la productivité, de réduire les coûts de maintenance tout en utilisant au mieux la capacité de la flotte. Cependant, le problème de planification conjointe pour une flotte est un problème complexe à résoudre nécessitant de considérer trois dimensions. La première est de planifier conjointement les missions et les maintenances de façon statique. La seconde est d’intégrer, de façon dynamique, les informations de surveillance disponibles et les différents événements pouvant se produire pour mettre à jour le planning. La troisième dimension est la dimension flotte qui implique de gérer plusieurs véhicules en parallèle. La première étape consiste à planifier conjointement les activités de maintenance et les missions pour un camion dans un cas statique. On suppose alors qu’on connait toutes les missions à planifier et qu’aucune information de surveillance n’est disponible. Pour cela, on définit un modèle de dégradation du véhicule afin d’estimer sa durée de vie résiduelle pour prendre les décisions. C’est un modèle avec des valeurs de paramètres variables car le véhicule évolue dans des conditions de sévérité d’usage différentes en fonction des missions. Il est le point central pour mettre en place un algorithme de planification afin d’éviter les risques de panne trop importants. La planification est naturellement optimisée en fonction d’un critère basé soit sur les coûts de maintenance, soit sur les revenus d’exploitation. Une fois cette méthodologie définie, elle est complétée pour intégrer les informations relatives à la dégradation du véhicule, les occurrences de panne et les nouvelles missions qui peuvent demandées. Une approche dynamique pour résoudre le problème de planification pour un véhicule a donc été développée. Si une panne survient, le planning est mis à jour car il n’est plus adapté à l’évolution de la dégradation réelle du véhicule. De même, lorsque qu’une nouvelle mission est disponible, une mise à jour est indispensable car l’ordre de priorité des missions, défini par leurs dates limites de livraison, doit être pris en compte au plus vite pour éviter les pénalités de retard. En revanche, une information de dégradation peut avoir une influence variable sur le planning en cours. Il s’agit donc d’étudier la robustesse du planning pour éviter de changer trop souvent l’ordre des missions et les dates de maintenance. La dernière étape consiste à intégrer la dimension flotte dans la prise de décision. Ce n’est donc plus juste une question d’ordre des missions et de planification des maintenances au bon moment mais il faut également décider à quelle mission est attribuée à quel véhicule. La prise de décision dépend alors de l’état de la flotte. Une analyse de l’impact de la prise en compte de la dimension flotte dans le cas statique, puis dans le cas dynamique est menée. Des résultats de simulation permettent d’illustrer les méthodes développées et de montrer leur intérêt et les gains en termes de coûts qu’elles engendrent.

International audience; Human-driven global environmental changes have considerably increased the risk of biological invasions, especially the spread of human parasites and their vectors. Among exotic species that have major impacts on public health, the dengue fever mosquito Aedes aegypti originating from Africa has spread worldwide during the last three centuries. Although considerable progress has been recently made in understanding the history of this invasion, the respective roles of human and abiotic factors in shaping patterns of genetic diversity remain largely unexplored. Using a genome-wide sample of genetic variants (3,530 ddRAD SNPs), we analyzed the genetic structure of Ae. aegypti populations in the Caribbean, the first introduced territories in the Americas. Fourteen populations were sampled in Guyane and in four islands of the Antilles that differ in climatic conditions, intensity of urbanization, and vector control history. The genetic diversity in the Caribbean was low (He = 0.14-0.17), as compared with a single African collection from Benin (He = 0.26) and site-frequency spectrum analysis detected an ancient bottleneck dating back ∼300 years ago, supporting a founder event during the introduction of Ae. aegypti. Evidence for a more recent bottleneck may be related to the eradication program undertaken on the American continent in the 1950s. Among 12 loci detected as FST-outliers, two were located in candidate genes for insecticide resistance (cytochrome P450 and voltage-gated sodium channel). Genome-environment association tests identified additional loci associated with human density and/or deltamethrin resistance. Our results highlight the high impact of human pressures on the demographic history and genetic variation of Ae. aegypti Caribbean populations.

Snow interception by the forest canopy controls the spatial heterogeneity of subcanopy snow accumulation leading to significant differences between forested and nonforested areas at a variety of scales. Snow intercepted by the forest canopy can also drastically change the surface albedo. As such, accurately modeling snow interception is of importance for various model applications such as hydrological, weather, and climate predictions. Due to difficulties in the direct measurements of snow interception, previous empirical snow interception models were developed at just the point scale. The lack of spatially extensive data sets has hindered the validation of snow interception models in different snow climates, forest types, and at various spatial scales and has reduced the accurate representation of snow interception in coarse-scale models. We present two novel empirical models for the spatial mean and one for the standard deviation of snow interception derived from an extensive snow interception data set collected in an evergreen coniferous forest in the Swiss Alps. Besides open-site snowfall, subgrid model input parameters include the standard deviation of the DSM (digital surface model) and/or the sky view factor, both of which can be easily precomputed. Validation of both models was performed with snow interception data sets acquired in geographically different locations under disparate weather conditions. Snow interception data sets from the Rocky Mountains, US, and the French Alps compared well to the modeled snow interception with a normalized root mean square error (NRMSE) for the spatial mean of ≤10 % for both models and NRMSE of the standard deviation of ≤13 %. Compared to a previous model for the spatial mean interception of snow water equivalent, the presented models show improved model performances. Our results indicate that the proposed snow interception models can be applied in coarse land surface model grid cells provided that a sufficiently fine-scale DSM is available to derive subgrid forest parameters.

This work analyses the EMI problems that may arise in the large electric networkson industrial plants, taking into account the switching harmonics injected in these systems bypower converters. The harmonics were studied in the frequency band from DC up to a few tens ofMHz. To model the propagation of the switching harmonics in long electric cables, an accurateand computationally ecient simulation method is proposed. It is t to simulate the behaviorof medium frequency parasitic signals in large cabling networks, e.g. on industrial plants, buildings,and others. This method can be useful in the designing of such systems, contributing tothe development of protection measures against dysfunction or damage that may be caused byEMI phenomena in the network.; Dans cette thèse sont analysés les problèmes liés à la CEM qui peuvent se produiredans un réseau électrique industriel de grandes dimensions, prenant en compte les harmoniquesintroduits dans le système par le découpage des convertisseurs de puissance. Les harmoniques ontété étudiés dans la bande de fréquence entre DC et quelques dizaines de MHz. Pour modéliserla propagation des harmoniques de découpage dans les longs câbles électriques, une méthode desimulation précise et de bas coût computationnel a été proposée. Cette méthode est adaptée poursimuler le comportement des signaux parasite dans les câblages longs présents dans les réseauxindustriels, des bâtiments ou autre, et peut être utile pour le dimensionnement de ces réseaux, envue du développement de méthodes de protection contre des dysfonctionnements et dommagesqui peuvent être causés par des phénomènes d'interférence électromagnétique.

International audience; Flash floods are amongst the most important natural hazards in Europe, particularly in the Mediterranean region creating economical damage and life risk. This study investigates the factors that control the hydrological response in a set of 13 catchments, partially nested and ranging from 0.17 to 42 km2, located in Ardèche, a Mediterranean region prone to flash floods. The period of interest is 2012-2015. The Claduègne catchment (42 km2), which contains the other 12 catchments, is part of the OHMCV observatory and the OZCAR research infrastructure. This catchment can be separated into two distinctively different parts with a basaltic plateau in the upstream part and sedimentary rock in the downstream part (each about 50%). The sub-catchments are distributed over these two parts and different land use forms (forest, cultivated soils and grasslands). For most of the sub-catchments, no discharge rating curve exists, so the focus of the analysis mainly lies on the time component of the hydrological response as well as on descriptors of the rainfall-runoff event and catchment properties. Several characteristic times were calculated for each catchment based on a set of 49 to 158 events depending on the catchment and various statistical methods were applied in order to estimate the importance of different factors on the hydrological response on two levels: (A) inter-comparison of the catchments with regards to their properties and averaged event characteristics. (B) comparison of the storm events for each catchment considered separately with regards to the rain characteristics, initial degree of wetness and seasonality. A simple estimate of lag time was shown to be able to characterize the dynamics of each catchment and provide an estimate of time of concentration, if calculated for a selection of impulsive events. A relationship between catchment size and parsimonious time step to describe rainfall forcing was also established. Besides the catchment's size, we found the geology to be an important factor influencing the catchments' response, with the catchments in the sedimentary part reacting faster. On the catchment-level, a strong seasonal variation of event characteristics was found. The most intense, shortest events take place in autumn, while the events in spring are particularly long and slow. Two sub-catchments have singular behaviors. One was shown to react much faster and one much slower than expected. This suggests additional in-situ investigations in order to understand the hydrological processes.

[Departement_IRSTEA]Eaux [TR1_IRSTEA]ARCEAU [ADD1_IRSTEA]Hydrosystèmes et risques naturels; International audience; OZCAR, the French Critical Zone Research Infrastructure (RI) gathers around 20 observatories sampling various compartments of the Critical Zone, in France and in southern countries. Given their long history, most of them have developed their own data/metadata portals. There is however a need to gather all the data in a common Information System (Theia-OZCAR IS) to make the data visible, findable and easy to explore; allow their preservation and their citation; favor their reuse and sharing; be interoperable with European infrastructures by adopting international standards (controlled vocabularies and OGC compliant webservice). To build the portal, the project team visited the existing data centers and future users to understand current practices and collect future users' needs. This revealed the heterogeneous levels of data management maturity, variable names nomenclature and data exposition; and that finding data by variables was the point of interest of future users. The starting postulate when building the Theia-OZCAR IS is that databases stay next to data producers, which ensures the best data quality. A continuous information flow between observatories IS and the Theia-OZCAR IS will keep information up to date. Suppliers push data and metadata to the Theia-OZCAR IS, through a common data model, using an extraction script maintained locally and the data portal will provide an advanced search interface to explore the data as well as standardized services that can be harvested by other portals. The paper presents the approach and the first portal prototype, based on principles that can be reused by other disciplines/data portals.

[Departement_IRSTEA]Eaux; International audience; A large part of total solid flux is transported as suspension in mountainous rivers. It is crucial for water resource management and for environmental issues to be able to model and to understand these fluxes. However, suspended load is known to be highly variable in time and space, as fine sediments can originate from various erosion processes and from various sources. Among the different methodologies available for analyzing the suspended sediment flux dynamics, hysteretic loops in discharge and suspended load signals are commonly used to assess sediment sources and production processes. However, the shape of these loops is often analyzed qualitatively for a single or a small number of catchments. Hence it is still unclear how the geomorphological catchment properties influence the variability of the flow rate - suspended sediment concentration relationship through the hysteresis effects. This is particularly true in mountainous catchments where important sources of fine sediments may originate from the river bed in addition to hillslopes. In this study we analyzed quantitatively ten long-term series of high-frequency observations of suspended sediment load measured in contrasted alpine catchments. Hysteresis effects were analyzed in a high number of automated sampled events and the dominant response for each catchment was sought. This was done by using a normalized hysteresis index developed by Lloyd et al. (2016), which we weighted by the mass transported during each event. The various catchments were characterized with a normalized geomorphological index expressing the relative importance of sediment sources originating from the river bed or from eroded areas as a function of the distance to the outlet of the catchment. The dominant hysteresis response of the ten alpine catchments studied was found to be greatly linked to their geomorphological index. These results suggest that the sediment source configuration upstream of a measuring station drives hysteresis effects and thus the variability of the flow rate-suspended sediment concentration relationship.

This work analyses the EMI problems that may arise in the large electric networkson industrial plants, taking into account the switching harmonics injected in these systems bypower converters. The harmonics were studied in the frequency band from DC up to a few tens ofMHz. To model the propagation of the switching harmonics in long electric cables, an accurateand computationally ecient simulation method is proposed. It is t to simulate the behaviorof medium frequency parasitic signals in large cabling networks, e.g. on industrial plants, buildings,and others. This method can be useful in the designing of such systems, contributing tothe development of protection measures against dysfunction or damage that may be caused byEMI phenomena in the network., Dans cette thèse sont analysés les problèmes liés à la CEM qui peuvent se produiredans un réseau électrique industriel de grandes dimensions, prenant en compte les harmoniquesintroduits dans le système par le découpage des convertisseurs de puissance. Les harmoniques ontété étudiés dans la bande de fréquence entre DC et quelques dizaines de MHz. Pour modéliserla propagation des harmoniques de découpage dans les longs câbles électriques, une méthode desimulation précise et de bas coût computationnel a été proposée. Cette méthode est adaptée poursimuler le comportement des signaux parasite dans les câblages longs présents dans les réseauxindustriels, des bâtiments ou autre, et peut être utile pour le dimensionnement de ces réseaux, envue du développement de méthodes de protection contre des dysfonctionnements et dommagesqui peuvent être causés par des phénomènes d'interférence électromagnétique.

International audience; The past decades have seen an increasing interest on the biology of photosynthetic species living in aquatic environments, including diverse organisms collectively called "algae." If we consider the relative size of scientific communities, marine and freshwater plants have been overall less studied than terrestrial ones. The efforts put on land plants were motivated by agriculture and forestry, applications for human industry, easy access to terrestrial ecosystems, and convenient cultivation methods in fields or growth chambers. By contrast, the fragmentary knowledge on the biology of algae, the hope to find in this biodiversity inspiration for biotechnologies, and the emergency created by the environmental crisis affecting oceans, lakes, rivers, or melting glaciers, have stressed the importance to make up for lost time. Needed efforts embrace a broad spectrum of disciplines, from environmental and evolutionary sciences, to molecular and cell biology. In this multiscale view, functional genomics and ecophysiology occupy a pivotal position linking molecular and cellular analyses and ecosystem-level studies. Without pretending to be exhaustive and with few selected references, six grand challenges, requiring multidisciplinary approaches, are introduced below.

International audience; The transport of suspended sediment is associated with important social, economic, and environmental issues. It is still unclear, however, how suspended sediments eroded on hillslopes are transferred downstream through the river system. In this study, we aimed to investigate this process by applying a sediment budget approach to a typical 3.5-km-long Alpine braided reach. Using high-frequency suspended load measurements combined with Monte Carlo simulations for uncertainty propagation, we observed a significant buffering behavior of the reach studied. Thirty-two of the 48 events observed during the 2-month campaign showed significant differences between upstream and downstream mass transported as suspension, despite the reach studied was short compared to the upstream drainage area (130 km(2)). These differences at the event scale varied widely within an envelope comprised between a net erosion equivalent to 74% of upstream suspended mass and a net deposition equivalent to 71%. Budgets were found to be controlled at a nearly instantaneous time scale by the liquid discharges and the suspended sediment concentrations in an opposite way: for low upstream concentrations, net erosion increased when the discharges increased, while above a certain concentration, net deposition increased when the concentrations increased. Moreover, coarse particles mobility in the reach (characterized via bedload transport measurements) appeared to have a strong influence on the availability of suspended particles as both quantities evolved concomitantly through time. These observations have important implications for our understanding and modeling of the transfer of suspended particles in gravel bedded streams.

Territorial ecology is a research field which proposes to analyse the functioning of a territory under the perspective of the flows of matter and energy which passes by and characterize it. This analysis is particularly led through the concept of territorial metabolism. Through this lens, flows are considered in their material dimension but also under the light of the actor systems and of the political and socio-economic issues which influence them. Thus, territorial ecology tends to underline socio-ecological transition levers on the scale of territories.This thesis proposes to test these concepts through a field study in the mid Rhône valley. Looking back to the end of the 18th century, the research firstly underlines how a socio-ecological regime is progressively set around the industry sector and the heavy infrastructures at the scale of the territory. Then, the thesis describes how this regime gets materialized into today’s metabolism through the analysis of four different kinds of flows (energy, water, toxic elements, food). This metabolism is described as intensive and toxic – according to the level of intensity and toxicity of the flows at stake – as well as absorbing – in the way it deals with other territories’ metabolic functions (waste management, food production). These properties of the Rhône-Médian’s metabolism implicate limited capacity for local actors (inhabitants, public actors, farmers) to act towards the reduction or the transformation of these flows. However, within a context of change in production systems and of residentialisation, several local initiatives emerge. Through this process, local actors gain a better understanding and better capabilities to act on the flows of energy and matter in order to engage with sustainable territorial development. These local initiatives lead to several forms of reassessment of existing power relationships but the industrial socio-ecological regime remains, partly because some lock-ins which structure and self-sustain this regime are not questioned.; L’écologie territoriale est un champ de recherche qui propose d’analyser le fonctionnement d’un territoire sous l’angle des flux de matières et d’énergie qui le traversent et le caractérisent. Cette analyse est notamment menée à travers le concept du métabolisme territorial. Sous cet angle, les flux sont envisagés à la fois dans leur dimension matérielle et à la lumière des systèmes d’acteurs et des enjeux socio-économiques et politiques qui les influencent. L’écologie territoriale tend en cela à mettre en exergue des leviers de transition socio-écologique à l’échelle des territoires.Cette thèse propose la mise à l’épreuve de ces concepts à travers un terrain d’étude situé dans la moyenne vallée du Rhône. En remontant à la fin du XVIIIe siècle, la recherche souligne tout d’abord comment se met en place, à l’échelle de celui-ci, un régime socio-écologique fondé sur l’industrie et les infrastructures lourdes. Ensuite, à partir de l’analyse de quatre types de flux (énergétiques, hydriques, toxiques, alimentaires), la thèse propose de caractériser la manière dont ce régime se matérialise aujourd’hui dans le métabolisme. Ce métabolisme est alors qualifié d’intensif et de toxique – par l’intensité et la toxicité des flux mis en jeu – ainsi que d’absorbant – en ce qu’il assure des fonctions métaboliques répondant aux besoins d’autres territoires (traitement de déchets, production alimentaire). Les caractéristiques de ce métabolisme impliquent alors une faible capacité des acteurs locaux (habitants, acteurs publics, agriculteurs) à agir sur les flux pour leur réduction ou leur transformation. Pourtant, dans un contexte de mutations des systèmes productifs et de résidentialisation, plusieurs initiatives émergent de ces mêmes acteurs locaux pour comprendre et agir sur les flux de matière et d’énergie, dans une perspective de développement territorial durable. Celles-ci conduisent à des formes de remise en question des équilibres de pouvoir existants mais le régime socio-écologique industriel persiste, en partie en ce que les verrous qui le structurent et l’auto-entretiennent ne sont pas questionnés.

Territorial ecology is a research field which proposes to analyse the functioning of a territory under the perspective of the flows of matter and energy which passes by and characterize it. This analysis is particularly led through the concept of territorial metabolism. Through this lens, flows are considered in their material dimension but also under the light of the actor systems and of the political and socio-economic issues which influence them. Thus, territorial ecology tends to underline socio-ecological transition levers on the scale of territories.This thesis proposes to test these concepts through a field study in the mid Rhône valley. Looking back to the end of the 18th century, the research firstly underlines how a socio-ecological regime is progressively set around the industry sector and the heavy infrastructures at the scale of the territory. Then, the thesis describes how this regime gets materialized into today’s metabolism through the analysis of four different kinds of flows (energy, water, toxic elements, food). This metabolism is described as intensive and toxic – according to the level of intensity and toxicity of the flows at stake – as well as absorbing – in the way it deals with other territories’ metabolic functions (waste management, food production). These properties of the Rhône-Médian’s metabolism implicate limited capacity for local actors (inhabitants, public actors, farmers) to act towards the reduction or the transformation of these flows. However, within a context of change in production systems and of residentialisation, several local initiatives emerge. Through this process, local actors gain a better understanding and better capabilities to act on the flows of energy and matter in order to engage with sustainable territorial development. These local initiatives lead to several forms of reassessment of existing power relationships but the industrial socio-ecological regime remains, partly because some lock-ins which structure and self-sustain this regime are not questioned.; L’écologie territoriale est un champ de recherche qui propose d’analyser le fonctionnement d’un territoire sous l’angle des flux de matières et d’énergie qui le traversent et le caractérisent. Cette analyse est notamment menée à travers le concept du métabolisme territorial. Sous cet angle, les flux sont envisagés à la fois dans leur dimension matérielle et à la lumière des systèmes d’acteurs et des enjeux socio-économiques et politiques qui les influencent. L’écologie territoriale tend en cela à mettre en exergue des leviers de transition socio-écologique à l’échelle des territoires.Cette thèse propose la mise à l’épreuve de ces concepts à travers un terrain d’étude situé dans la moyenne vallée du Rhône. En remontant à la fin du XVIIIe siècle, la recherche souligne tout d’abord comment se met en place, à l’échelle de celui-ci, un régime socio-écologique fondé sur l’industrie et les infrastructures lourdes. Ensuite, à partir de l’analyse de quatre types de flux (énergétiques, hydriques, toxiques, alimentaires), la thèse propose de caractériser la manière dont ce régime se matérialise aujourd’hui dans le métabolisme. Ce métabolisme est alors qualifié d’intensif et de toxique – par l’intensité et la toxicité des flux mis en jeu – ainsi que d’absorbant – en ce qu’il assure des fonctions métaboliques répondant aux besoins d’autres territoires (traitement de déchets, production alimentaire). Les caractéristiques de ce métabolisme impliquent alors une faible capacité des acteurs locaux (habitants, acteurs publics, agriculteurs) à agir sur les flux pour leur réduction ou leur transformation. Pourtant, dans un contexte de mutations des systèmes productifs et de résidentialisation, plusieurs initiatives émergent de ces mêmes acteurs locaux pour comprendre et agir sur les flux de matière et d’énergie, dans une perspective de développement territorial durable. Celles-ci conduisent à des formes de remise en question des équilibres de pouvoir existants mais le régime socio-écologique industriel persiste, en partie en ce que les verrous qui le structurent et l’auto-entretiennent ne sont pas questionnés.

We want a biped robot to walk safely in a crowd. This involves two aspects: balance and col- lision avoidance. The first implies avoiding kinematic and dynamical failures of the unstable walking dynamics of the robot; the second refers to avoiding collisions with people. We want to be able to solve both problems not only now but also in the future. We can ensure balance indefinitely by entering in a cyclic walk or by making the robot stop after a couple of steps. Nonetheless, we cannot give a comparable guarantee in collision avoidance for many reasons: impossibility of having absolute knowledge of where people are moving, kinematic/dynamical limitations of the robot, adversarial crowd motion, etc. We address this limitation with a standard strategy for crowd navigation, known as passive safety, that allows us to formulate a unified Model Predictive Control approach for balance and collision avoidance in which we require the robot to stop safely in finite time. In addition, we define a novel safe navigation strategy based on the premise of avoiding collisions for as long as possible that minimizes their occurrence and severity. We propose a lexicographic formulation that produces motions that comply with such premise.We increase the degrees of freedom of the locomotion of a biped robot by allowing the duration and orientation of its steps to vary online. This introduces nonlinearities in the con- straints of the optimization problems we solve. We approximate these nonlinear constraints with safe linear constraints so that satisfying the latter implies satisfying the former. We pro- pose a novel method (Safe Sequential Quadratic Programming) that ensures feasible Newton iterates in the solution of nonlinear problems based on this redefinition of constraints.We make a series of simulations of a biped robot walking in a crowd to evaluate the performance of our proposed controllers. We are able to attest the reduction in the number and in the severity of collisions with our proposed navigation strategy in comparison with passive safety, specially when there is uncertainty in the motion of people. We show typical behaviors of the robot that arise when we allow the online variation of the duration and orientation of the steps and how it further improves collision avoidance. We report the computational cost of our proposed numerical method for nonlinear problems in comparison with a standard method. We show that we only need one Newton iteration to arrive to a feasible solution but that the CPU time is dependent on the amount of active set factorizations needed to arrive to the optimal active set.; Un robot bipède doit pouvoir marcher en toute sécurité dans une foule. Pour cela, il faut prendre en compte deux aspects : l'équilibre et l’évitement des collisions. Maintenir l’équilibre implique d’éviter les défaillances dynamiques et cinématiques de la dynamique instable du robot. Pour ce qui est de l’évitement des collisions, il s’agit d’éviter le contact entre le robot et des individus. Nous voulons être capables de satisfaire ces deux contraintes simultanément, à l’instant présent mais aussi dans le futur. Nous pouvons assurer l’équilibre du robot indéfiniment en le faisant entrer dans un cycle limite de marche ou en le faisant s’arrêter après quelques pas. Néanmoins, une telle garantie pour l’évitement d’obstacle n’est pas possible pour plusieurs raisons : impossibilité de connaître de manière absolue la direction vers laquelle les individus se dirigent, limitations cinématiques et dynamiques du robot, mouvement non-coopératif de la foule, etc. Nous traitons ces limitations avec une stratégie standard de navigation dans une foule, appelée passive safety, qui nous permet de formuler une loi de commande prédictive avec laquelle nous assurons l’équilibre et l’évitement des collisions, de manière unifiée, en faisant s’arrêter le robot de manière sécurisée et en temps fini. De plus, nous définissons une nouvelle stratégie de navigation sûre basée sur le principe d’évitement des collisions aussi longtemps que possible, qui a la propriété de minimiser leur apparition et sévérité. Nous proposons une formulation lexicographique qui synthétise des mouvements conformes à ce principe.Nous augmentons les degrés de liberté de la locomotion d’un robot bipède en permettant la variation de l’orientation et de la durée des pas en ligne. Cependant, cela introduit des non-linéarités dans les contraintes de nos problèmes d’optimisation. Nous faisons des approximations de ces contraintes non-linéaires avec des contraintes linéaires sûres de sorte que la satisfaction des secondes implique la satisfaction des premières. Nous proposons une nouvelle méthode de résolution des problèmes non-linéaires (Optimisation Quadratique Successive Sûre) qui assure la faisabilité des itérations de Newton en utilisant cette redéfinition des contraintes.Nous simulons la marche d’un robot bipède dans une foule pour évaluer la performance de nos lois des commandes. D’une part, nous réussissons à réduire (statistiquement) la quantité et la sévérité des collisions en comparaison avec la méthode de passive safety, spécialement dans les conditions d’incertitude de la marche du robot dans une foule. D’autre part, nous montrons des exemples de comportements typiques du robot, qui découlent de la liberté de choisir l’orientation et la durée des pas. Nous rapportons le coût de calcul de notre méthode de résolution des problèmes non-linéaires en comparaison avec une méthode standard. Nous montrons qu’une seule itération de Newton est nécessaire pour arriver à une solution faisable, mais que le coût de calcul dépend du nombre de factorisations de l’active set dont nous avons besoin pour arriver à l’active set optimal.

The purpose of this study is to propose : (i) a new low thermal inertia mold concept for rapid manufacturing of high performance composite materials in order to meet industrial challenges, (ii) a new modeling approach for suitable thermomechanical optimizations based on the exploitation of an inexpensive finite element model. This approach relies on the three following tasks : (i) to develop a process for the convective coefficient estimation and for the thermoregulator modeling, both taking into account heating technological constrains (fluid nature, thermal power, thermal regulation, pump), (ii) to develop a thermomechanical optimization approach under stress, based on surrogate methods and optimization by genetic algorithm, (iii) to approve the whole approach using experimental campaigns allowing the comparison with numerical results., Ce travail a pour but de proposer : (i) un nouveau concept d’outillage à faible inertie thermique destiné à la transformation rapide des composites hautes performances visant à répondre aux enjeux industriels, (ii) une nouvelle approche du dimensionnement et de l’optimisation thermique de l’outillage basée sur l’exploitation d’un modèle éléments finis peu coûteux. La démarche s’appuie sur trois axes principaux : (i) mettre en place un processus permettant d’estimer le coefficient convectif et de modéliser le thermorégulateur avec la prise en compte des données technologiques du système de chauffe (fluide, puissance thermique, régulation, pompe),(ii) développer une démarche d’optimisation thermomécanique sous contrainte, reposant sur des méthodes de métamodélisation et d’optimisation par algorithme génétique, (iii) qualifier la démarche complète à l’aide de campagnes expérimentales permettant la confrontation aux résultats numériques.

The purpose of this study is to propose : (i) a new low thermal inertia mold concept for rapid manufacturing of high performance composite materials in order to meet industrial challenges, (ii) a new modeling approach for suitable thermomechanical optimizations based on the exploitation of an inexpensive finite element model. This approach relies on the three following tasks : (i) to develop a process for the convective coefficient estimation and for the thermoregulator modeling, both taking into account heating technological constrains (fluid nature, thermal power, thermal regulation, pump), (ii) to develop a thermomechanical optimization approach under stress, based on surrogate methods and optimization by genetic algorithm, (iii) to approve the whole approach using experimental campaigns allowing the comparison with numerical results.; Ce travail a pour but de proposer : (i) un nouveau concept d’outillage à faible inertie thermique destiné à la transformation rapide des composites hautes performances visant à répondre aux enjeux industriels, (ii) une nouvelle approche du dimensionnement et de l’optimisation thermique de l’outillage basée sur l’exploitation d’un modèle éléments finis peu coûteux. La démarche s’appuie sur trois axes principaux : (i) mettre en place un processus permettant d’estimer le coefficient convectif et de modéliser le thermorégulateur avec la prise en compte des données technologiques du système de chauffe (fluide, puissance thermique, régulation, pompe),(ii) développer une démarche d’optimisation thermomécanique sous contrainte, reposant sur des méthodes de métamodélisation et d’optimisation par algorithme génétique, (iii) qualifier la démarche complète à l’aide de campagnes expérimentales permettant la confrontation aux résultats numériques.

International audience; Artificial basins are used to recharge groundwater by many municipalities to improve the sustainability of storm water management. Despite its increasing operational implementation, artificial recharge still raises numerous questions related to its impact on groundwater quality. In this paper, a 3D numerical model of MAR basin/ aquifer system was implemented in order to simulate the fate of water and pollutants. It was used to illustrate the complex distribution in time and space of a tracer contaminant injected in the basin. The model was based on a well instrumented storm water infiltration basin located in Chassieu (Lyon area, France). The well-known Richards model was used to simulate the water flow in the saturated and unsaturated zone of the study site. The transfer of solutes in the basin/aquifer system was modelled by the advection-dispersion-equation (ADE). The model was calibrated during a rain event using hydraulic head and electric conductivity data from a set of piezometers located around the basin. The flow model was validated on a one month period of basin operation presenting several rain events. The model was then used to simulate the fate of a solute pollutant considered as a tracer during a high intensity rain event. This simplified test case illustrated the mechanism of capillary trapping in the vadose zone and the effect of sampling point location on concentration measurements. Three main results were obtained: (1) capillary trapping promoted a retention of up to 20% of the injected tracer in the vadose zone, (2) 0 to 24% of the injected solute concentration could be recovered depending on the piezometer location, (3) the averaged concentration decreased by 50% if the measuring device is lowered by 5 m under the water table. These results were strongly site and event dependant but observed trends should be considered while discussing punctual water quality measurements used to monitor MAR systems. It also allowed to suggest some guidelines for sampling point positioning.

16 pags., 7 figs., 2 tabs., We have analyzed potential harmful trace elements (PHTE; Pb, Hg, Zn, As and Cu) on sediment cores retrieved from lake Marboré (LM) (2612 m a.s.l, 42°41′N; 0° 2′E). PHTE variability allowed us to reconstruct the timing and magnitude of trace metal pollutants fluxes over the last 3000 years in the Central Pyrenees. A statistical treatment of the dataset (PCA) enabled us to discern the depositional processes of PHTE, that reach the lake via direct atmospheric deposition. Indeed, the location of LM above the atmospheric boundary layer makes this lake an exceptional site to record the long-range transport of atmospheric pollutants in the free troposphere. Air masses back-trajectories analyses enabled us to understand the transport pathways of atmospheric pollutants while lead isotopic analyses contributed to evaluate the source areas of metal pollution in SW Europe during the Late Holocene. PHTE variability, shows a clear agreement with the main exploitation phases of metal resources in Southern Europe during the Pre-Industrial Period. We observed an abrupt lead enrichment from 20 to 375 yrs CE mostly associated to silver and lead mining and smelting practices in Southern Iberia during the Roman Empire. This geochemical data suggests that regional atmospheric metal pollution during the Roman times rivalled the Industrial Period. PHTE also increased during the High and Late Middle Ages (10–15 centuries) associated to a reactivation of mining and metallurgy activities in high altitude Pyrenean mining sites during climate amelioration phases. Atmospheric mercury deposition in the Lake Marboré record mostly reflects global emissions, particularly from Almadén mines (central Spain) and slightly fluctuates during the last three millennia with a significant increase during the last five centuries. Our findings reveal a strong mining-related pollution legacy in alpine lakes and watersheds that needs to be considered in management plans for mountain ecosystems as global warming and human pressure effects may contribute to their future degradation., Financial support has been received by the Sobrarbe Geoparkhrough the project“Reconstrucción de la minería histórica en la Comarca del Sobrarbe y su impacto ambiental durante el Antropoceno”and by the Spanish Ministry of Economy and Competitiveness(MINECO) project MEDLANT (CGL2016-76215-R). This work is also supported by the FEDER funds through the INTERREG V-A Spain-France-Andorra (POCTEFA 2014-2020, REPLIM project, Ref. EFA056/15)

Mastering the visual quality of industrial goods is a more and more important concern for companies nowadays, in numerous business sectors. In order to ensure this mastery, industrial companies adopt methods and processes based on visual inspection of products. Nonetheless, human visual inspection in the industry is showing a problematical variability of its results, partly due to the subjective aspect of this kind of control. From this assessment, several strategies has been developed to reduce this variability. The first one consists in modelling and formalizing the human control process to help industrial operators to control more repeatedly. The second lies in developing automated inspection systems, naturally very repeatable, but however still currently not very flexible and adaptable in terms of applications. The development of more generic systems, capable of detecting various types of anomalies on various types of products, is a current challenge for the automated inspection.This thesis work deals with bringing these two approaches together. Drawing inspiration from the human visual control processes to develop an automated control system, and more precisely from the use of various lighting angles to observe a product, we aim to bring together the strong repeatability of automatedsystems with the flexibility of the human practices. To this end, a detailed study is proposed, from the specifications of an automated inspection system inspired by the human control in an industrial context, to the development of its different components : the acquisition of multi-lighting information, the extraction of features from the images and their reduction, and finally the classification leading to a decision concerning the product’s quality. For each step a bibliographic study of the existing methods is produced and contrasted with the industrial constrains. Moreover, some innovative methodological contributions for the extraction and the reduction of features are also proposed. The first one consists in using coefficients coming from Discrete Modal Decomposition of images as relevant features for classification. The second one lies in proposing a new feature selection method using a criteria based on T² statistic and control charts. The union between the bibliographic investigations and the methodological contributions coming out of this thesis work leads finally to a proposition for an innovative approach of automated visual control using a multi-lighting information. The implementation of this approach on industrial plastic samples enable to highlight the interest of this method to detect visual defects, in comparison to a more classic method using only one lighting angle.; La maitrise de la qualité visuelle des produits constitue un enjeu toujours plus important pour les entreprises à l’heure actuelle, dans de très nombreux secteurs d’application. Afin de garantir cette maîtrise, les industriels se dotent de méthodes et processus axés sur le contrôle visuel des produits. Néanmoins, le contrôle visuel humain en industrie est confronté à des problèmes de variabilité des résultats, dus en partie à l’aspect subjectif de ce type d’inspection. A partir de ce constat, différentes stratégies ont été développées pour réduire cette variabilité. La première consiste en la modélisation et la formalisation du contrôle humain pour aider les opérateurs à réaliser le contrôle de manière plus répétable. La seconde réside dans le développement de systèmes de contrôle automatisés, très répétables par nature, mais cependant encore à l’heure actuelle peu flexibles et adaptables en terme d’applications. Le développement de systèmes plus génériques en terme de variété de défauts à détecter et de types de pièces à observer constitue donc un challenge pour le domaine de l’inspection automatisée.Ce travail de thèse porte sur le rapprochement de ces deux approches. En s’inspirant des pratiques du contrôle visuel humain pour développer un système de contrôle automatisé, et plus particulièrement de l’exploitation de divers angles d’éclairages pour observer les produits, nous souhaitons allier la forte répétabilité des systèmes automatiques avec la flexibilité des pratiques humaines. Dans cet objectif, une étude détaillée est proposée, partant de la définition du cahier de charges d’un système de contrôle automatisé inspiré du contrôle humain dans un contexte industriel, puiss’intéressant ensuite à ses différentes composantes : l’acquisition de l’information multi-éclairages, l’extraction d’attributs des images et leur réduction, et enfin la classification menant à une décision quant à la qualité du produit inspecté. Pour chaque étape une étude bibliographique des méthodes existantes est menée et mise en regard des contraintes de l’application industrielle. De plus, des contributions méthodologiques innovantes pour l’extraction et la réduction d’attributs sont également proposées. La première consiste en l’utilisation de paramètres issus de la Décomposition Modale Discrète des images comme descripteurs pertinents dans un objectif de classification. La seconde réside dans la proposition d’une nouvelle méthode de sélection d’attributs mettant en oeuvre un critère d’évaluation fondé sur la statistique du T² et les cartes de contrôle. L’union des investigations bibliographiques et des contributions méthodologiques issues de ces travaux de thèse mène enfin à la proposition d’une approche innovante exploitant une information multi-éclairages pour le contrôle visuel automatisé. La mise en oeuvre de cette approche sur des échantillons issus de l’industrie plastique permet de mettre en avant l’intérêt de cette dernière pour la détection de défaut d’aspect par rapport à une méthode plus classique n’exploitant qu’un seul angle d’éclairage.

This paper describes an integrated, high-resolution dataset of hydro-meteorological variables (rainfall and discharge) concerning a number of high-intensity flash floods that occurred in Europe and in the Mediterranean region from 1991 to 2015. This type of dataset is rare in the scientific literature because flash floods are typically poorly observed hydrological extremes. Valuable features of the dataset (hereinafter referred to as EuroMedeFF database) include i) its coverage of varied hydro-climatic regions, ranging from Continental Europe through the Mediterranean to Arid climates, ii) the high space-time resolution radar-rainfall estimates, and iii) the dense spatial sampling of the flood response, by observed hydrographs and/or flood peak estimates from post-flood surveys. Flash floods included in the database are selected based on the limited upstream catchment areas (up to 3000 km2), the limited storm durations (up to 2 days), and the unit peak flood magnitude. The EuroMedeFF database comprises 49 events that occurred in France, Israel, Italy, Romania, Germany, and Slovenia, and constitutes a sample of rainfall and flood discharge extremes in different climates. The dataset may be of help to hydrologists as well as other scientific communities because it offers benchmark data for the identification and analysis of the hydro-meteorological causative processes, evaluation of flash flood hydrological models and for hydro-meteorological forecast systems. The dataset also provides a template for the analysis of the space-time variability of flash flood-triggered rainfall fields and of the effects of their estimation on the flood response modelling. The dataset is made available to the public as a "public dataset" with the following DOI: (https://doi.org/10.6096/mistrals-hymex.1493).

In modern society, use of information and communication technologies (ICTs) is a key component in the prevention of exclusion from many common modern day activities. ICTs could promote social engagement, facilitate access to social networks, and contribute to the improvement of the quality of life and management of patients suffering from Alzheimer-type disease. The aim of our doctoral research was to study the particular difficulties of olderpeople in using these technologies, but also the conditions of the assistance they can benefit from. The objective of this thesis project was to determine whether elderly encountered specific difficulties in using new ICT, in order to offer them an adapted support and to propose care and assistance professionals and volunteers a series of recommendations (a pedagogy) on how to learn the use of these technologies to people with moderate to severe cognitive disorders. Of particular interest in the present study are landline, mobile phones, and tablet computers, which are more readily portable, offer simpler functionality than most computers, and therefore are potentially very useful for aging people, included people with neurocognitive disorders. A performance-based assessment and a comparison of the capacity of ICT use of young and old adults has shown that older adults are characterized by a greater number of commission, unlike initiation, addition, or omission errors, and a need for more precise and explicit cues, especially for the use of mobile technologies. Exploring the link between the nature of errors produced in the use of ICTs and cognitive skills indicatedthe determinant factor of inhibition abilities as well as episodic memory, in particular the spontaneous recovery process, as has been observed in other contexts. These abilities were related to commission errors and not to omissions. The participation of people with neurocognitive disorders in a tablet computer-training program using the errorless learning and the spaced-retrieval technique allowed to improve performance as well as attitudes towards technologies. Structuring the informative environment and automation of some basic procedures essential to the use of ICTs therefore appears as a very probable orientation to alleviate the difficulties of the elderly.; Il est de plus en plus admis que les nouvelles technologies de l’information et de la communication (TIC) pourraient contribuer à la prévention de l’isolement et au développement du sentiment de bien-être des adultes âgés, ainsi qu’à l’amélioration de la qualité de vie et de prise en charge des patients souffrant de maladie de type Alzheimer. Le but de cette recherche doctorale a été d’étudier de manière approfondie les difficultés particulières des personnes âgées à utiliser ces technologies et les modalités de l’aide dont elles sont encore en capacité de bénéficier, ceci dans le but de proposer aux professionnels ou bénévoles du soin ou de l’accompagnement une série de recommandations (une pédagogie) sur l’art et la manière d’apprendre l’usage des ces technologies à des personnes atteintes de troubles cognitifs modérés à sévères. Notre recherche s’est en particulier intéressée au téléphone (fixe et mobile) et à la tablette tactile, celle-ci paraissant offrir l’avantage d’une plus grande simplicité d’utilisation que les ordinateurs, et ainsi présenter un intérêt particulier pour les adultes âgés avec ou sans troubles neurocognitifs. Les résultats d’évaluations en situation avec comparaison des capacités d’utilisation des TIC d’adultes jeunes et âgés montrent que ces derniers se caractérisent par un plus grand nombre d’erreurs d’exécution et non d’omissions, d’additions d’action ou d’erreurs d’initiation, ainsi qu’un réel besoin en aides plus précises et explicites. L’exploration du lien entre la nature des erreurs produites lors de l’utilisation des TIC et les compétences cognitives met en avant le caractère déterminant de la préservation des capacités d’inhibition et de la mémoire épisodique, en particulier du processus de récupération spontanée. Ces capacités se révèlent être liées aux erreurs d’exécution et non aux omissions comme cela a été observé dans d’autres contextes. La participation de personnes présentant des difficultés cognitives à un programme d’initiation à l’utilisation des tablettes tactiles, intégrant les principes de l’apprentissage sans erreur et de la récupération espacée, a permis d’améliorer les performances lors de leur utilisation et leur attitude générale à l’égard de la technologie. La recherche d’une structuration de l’environnement informatif et d’une automatisation de certaines procédures de base indispensables à l’utilisation des TIC constitue donc une approche favorable au dépassement ou contournement des difficultés des personnes âgées.

Thèse préparée dans le cadre d’une cotutelle entre la Communauté Université Grenoble Alpes et Nanyang Technological University, Singapour; The development of portable electronics, electric vehicles and renewable energies has attracted great interest in the search for new solutions for energy storage. The autonomy of current Li-ion batteries is not yet sufficient to meet the needs of these different applications. Indeed, graphite, the most used anode material, has a relatively low specific capacity of 372 mAh.g-1 which limits the battery life. It is therefore necessary to substitute graphite with a more efficient material. The ternary oxides of the AB2O4 type (A, B: transition metals) are particularly interesting candidates because of their relatively high specific capacity (from 750 to 1000 mAh.g-1). In particular, ZnFe2O4 is a promising material with a theoretical capacity of 1000 mAh.g-1 and a low working voltage (1.5V vs Li / Li +). It is also a cheap, abundant and non-toxic material. In addition, the nanostructuring of this material would ensure good mechanical stability and improve the kinetics of lithium during charge / discharge cycles. The objective of this thesis is the synthesis of ZnFe2O4 nanoparticles by a laser pyrolysis process and the evaluation of their electrochemical performances against metallic lithium. This thesis work is divided into two parts: firstly, the influence of various synthesis parameters (nature and flow rates of the gases, precursors used, etc.) on the crystalline phases and the morphologies obtained is studied. In a second step, several of the nanopowders obtained by laser pyrolysis are tested in half-cell cycling to evaluate the electrochemical performance and understand the mechanisms governing the storage of lithium in these materials. This thesis work was carried out jointly by the Grenoble-Alpes University and the Nanyang Technological University in Singapore, and in collaboration with the AIME laboratory of the University of Montpellier; Le développement de l’électronique portable, des véhicules électriques et des énergies renouvelables a suscité un grand intérêt dans la recherche de nouvelles solutions pour le stockage de l’énergie. L’autonomie des batteries Li-ion actuelles n’est pas encore suffisante pour répondre aux besoins de ces différentes applications. En effet, le graphite, matériau d’anode le plus utilisé, possède une capacité spécifique relativement faible de 372 mAh.g-1 qui limite l’autonomie des batteries. Il est donc nécessaire de substituer le graphite par un matériau plus performant. Les oxydes ternaires de type AB2O4 (A, B : métaux de transition) sont des candidats particulièrement intéressants de par leur capacité spécifique relativement élevée (de 750 à 1000 mAh.g-1). En particulier, ZnFe2O4 est un matériau prometteur avec une capacité théorique de 1000 mAh.g-1 et une faible tension de travail (1,5V vs Li/Li+). C’est aussi un matériau peu cher, abondant et non toxique. De plus, la nanostructuration de ce matériau permettrait d’assurer une bonne stabilité mécanique et d’améliorer la cinétique du lithium lors des cycles charge/décharge.L’objectif de cette thèse est la synthèse de nanoparticules de ZnFe2O4 par un procédé de pyrolyse laser et l’évaluation de leurs performances électrochimiques face à du lithium métallique. Ce travail de thèse se divise en deux parties : tout d’abord, l’influence de différents paramètres de synthèse (nature et débits des gaz, précurseurs utilisés, …) sur les phases cristallines et les morphologies obtenues est étudiée. Dans un second temps, plusieurs des nanopoudres obtenues par pyrolyse laser sont testées en cyclage en demi-cellule pour en évaluer les performances électrochimiques et comprendre les mécanismes régissant le stockage du lithium dans ces matériaux.Ce travail de thèse a été réalisé en cotutelle entre l’université Grenoble-Alpes et l’université technologique de Nanyang à Singapour, et en collaboration avec le laboratoire AIME de l’université de Montpellier.

To support the urban farm emergence trend in large metropolises, we propose decision support tools based on mathematical programs to design market gardening farms targetting the demands of different categories of clients in local fresh fruits and vegetables. Technical solutions develop rapdily, but the strong constraints linked to urban farming, such as limited surface and high operating costs, make difficult to define viable and sustainable business models for urban market gardeners. Three mixed integer linear programming models are presented : A tactical farm planning model, a plurennial strategic sizing model for diversified fruit and vegetable farms, and a client combination selection model. Numerical results and model performances are presented, based on multi-products, multi-techniques and multi-periods real cases. Our main contributions are the consideration of the perishable nature of fruits and vegetables in strategic production systems sizing models, including notably the investments and workforce sizing.; Pour accompagner le développement des fermes urbaines professionnelles et des circuits courts et de proximité dans les grandes métropoles, nous proposons des outils à base de programmes mathématiques d’aide à la conception de fermes maraîchères diversifiées ciblant les demandes de différents types de clients en fruits et légumes frais locaux. Les solutions techniques de culture en ville se développent rapidement, mais compte-tenu des contraintes fortes de la production agricole urbaine (foncier limité, coûts opérationnels élevés), la définition de modèles économiques viables pour des fermes pérennes est un vrai défi pour les maraîchers urbains. Trois modèles en programmation linéaire mixte sont présentés et confrontés aux résultats du terrain : un modèle de planification tactique des fermes maraîchères, un modèle de dimensionnement stratégique des fermes maraîchères et un modèle de sélection de la meilleure combinaison de clients. Des résultats numériques et les performances des modèles sont présentés à partir de cas concrets multi-produits, multi-techniqueset multi-périodes. Nos contributions résident dans la prise en compte de la périssabilité des produits frais dans le dimensionnement stratégique des systèmes de production, incluant le dimensionnement de la main d’oeuvre agricole.

Rare-earth-based (RE) nanolaminates have attracted attention recently because of their complicated magnetism and their potential as precursors for strongly correlated two-dimensional materials. In this work, we synthesized a class of nanolaminates with a Mo4RE4Al7C3 chemistry, where RE = Ce or Pr. Powder samples of both phases were characterized with respect to structure and composition. Single crystals of Mo4Ce4Al7C3 were used for magnetization measurements. The crystal structure was investigated by means of x-ray diffraction and scanning transmission electron microscopy. Magnetization analysis reveals a ferromagnetic ground state with a Curie temperature of similar to 10.5 K. X-ray absorption near-edge structure provides experimental evidence that Ce is in a mixed-valence state. X-ray magnetic circular dichroism shows that only the Ce atoms with 4f(1) configuration occupying one of the two possible sites are ferromagnetically coupled, with a saturation moment of similar to 1.2 mu(B) per atom. We thus classify Mo4Ce4Al7C3 as a ferromagnetic, mixed-valence compound. Funding Agencies|Knut and Alice Wallenberg (KAW) Foundation through a Fellowship [0358, KAW 2015.0043]; Swedish Research council [642-2013-8020]; Flag-ERA JTC; chair of excellence program of the Nanosciences Foundation (Universite Grenoble-Alpes Foundation); Federation Wallonie-Bruxelles through the Action de Recherche Concertee "3D nanoarchitecturing of 2D crystals" [16/21-077]; European Union [696656]; Belgium FNRS (Flag-ERA) [R. 50.01.18.F]; Fonds de la Recherche Scientifique de Belgique (F.R.S. -FNRS) [2.5020.11]; Linkoping Ultra Electron Microscopy Laboratory

In modern society, use of information and communication technologies (ICTs) is a key component in the prevention of exclusion from many common modern day activities. ICTs could promote social engagement, facilitate access to social networks, and contribute to the improvement of the quality of life and management of patients suffering from Alzheimer-type disease. The aim of our doctoral research was to study the particular difficulties of olderpeople in using these technologies, but also the conditions of the assistance they can benefit from. The objective of this thesis project was to determine whether elderly encountered specific difficulties in using new ICT, in order to offer them an adapted support and to propose care and assistance professionals and volunteers a series of recommendations (a pedagogy) on how to learn the use of these technologies to people with moderate to severe cognitive disorders. Of particular interest in the present study are landline, mobile phones, and tablet computers, which are more readily portable, offer simpler functionality than most computers, and therefore are potentially very useful for aging people, included people with neurocognitive disorders. A performance-based assessment and a comparison of the capacity of ICT use of young and old adults has shown that older adults are characterized by a greater number of commission, unlike initiation, addition, or omission errors, and a need for more precise and explicit cues, especially for the use of mobile technologies. Exploring the link between the nature of errors produced in the use of ICTs and cognitive skills indicatedthe determinant factor of inhibition abilities as well as episodic memory, in particular the spontaneous recovery process, as has been observed in other contexts. These abilities were related to commission errors and not to omissions. The participation of people with neurocognitive disorders in a tablet computer-training program using the errorless learning and the spaced-retrieval technique allowed to improve performance as well as attitudes towards technologies. Structuring the informative environment and automation of some basic procedures essential to the use of ICTs therefore appears as a very probable orientation to alleviate the difficulties of the elderly., Il est de plus en plus admis que les nouvelles technologies de l’information et de la communication (TIC) pourraient contribuer à la prévention de l’isolement et au développement du sentiment de bien-être des adultes âgés, ainsi qu’à l’amélioration de la qualité de vie et de prise en charge des patients souffrant de maladie de type Alzheimer. Le but de cette recherche doctorale a été d’étudier de manière approfondie les difficultés particulières des personnes âgées à utiliser ces technologies et les modalités de l’aide dont elles sont encore en capacité de bénéficier, ceci dans le but de proposer aux professionnels ou bénévoles du soin ou de l’accompagnement une série de recommandations (une pédagogie) sur l’art et la manière d’apprendre l’usage des ces technologies à des personnes atteintes de troubles cognitifs modérés à sévères. Notre recherche s’est en particulier intéressée au téléphone (fixe et mobile) et à la tablette tactile, celle-ci paraissant offrir l’avantage d’une plus grande simplicité d’utilisation que les ordinateurs, et ainsi présenter un intérêt particulier pour les adultes âgés avec ou sans troubles neurocognitifs. Les résultats d’évaluations en situation avec comparaison des capacités d’utilisation des TIC d’adultes jeunes et âgés montrent que ces derniers se caractérisent par un plus grand nombre d’erreurs d’exécution et non d’omissions, d’additions d’action ou d’erreurs d’initiation, ainsi qu’un réel besoin en aides plus précises et explicites. L’exploration du lien entre la nature des erreurs produites lors de l’utilisation des TIC et les compétences cognitives met en avant le caractère déterminant de la préservation des capacités d’inhibition et de la mémoire épisodique, en particulier du processus de récupération spontanée. Ces capacités se révèlent être liées aux erreurs d’exécution et non aux omissions comme cela a été observé dans d’autres contextes. La participation de personnes présentant des difficultés cognitives à un programme d’initiation à l’utilisation des tablettes tactiles, intégrant les principes de l’apprentissage sans erreur et de la récupération espacée, a permis d’améliorer les performances lors de leur utilisation et leur attitude générale à l’égard de la technologie. La recherche d’une structuration de l’environnement informatif et d’une automatisation de certaines procédures de base indispensables à l’utilisation des TIC constitue donc une approche favorable au dépassement ou contournement des difficultés des personnes âgées.

[Departement_IRSTEA]Eaux [TR1_IRSTEA]ARCEAU [ADD1_IRSTEA]Hydrosystèmes et risques naturels; International audience; OZCAR (Critical Zone Observatories: Research and Applications) is a national distributed infrastructure associatingmost of the French observation sites dedicated to the observation and monitoring of the Critical zone, the thinouter veneer of Earth's continents extending from the top of the vegetation canopy down to groundwater. OZCAR includes more than 60 highly instrumented sites/observatories for long-term measurements of biological,chemical and physical parameters of groundwater, river water, glaciers, soils, and wetlands in France and overseas.Each observatory focuses on one or more components of the CZ but importantly OZCAR is covering most of thelateral and vertical compartments of the CZ from mountains to costal areas.These observatories have been set up formerly to answer a local/regional scientific issue (ie. flood event prediction,acid rain resilience. . . ) but they all share the overarching question issue of predicting the response of the CZ toperturbation ranging from the second to the millions of year.They all aim at seeking and understanding the dynamic architecture of the CZ, identifying the elementaryprocesses in order to determine mass and energy budgets, to be implemented in numerical predictive models.OZCAR's crosscutting scientific approach to sites and disciplines using the breadth and richness of its observatoriesfrom mountains to costal areas will allow:- Concepts and instruments to be exchanged- To test hypotheses- To construct realistic predictive models of Earth's surface evolution in response to global change at the localscale.Through environmental data portal and modeling platforms, OZCAR is not only a research infrastructure opento the scientific community, it is also aiming at advising policy makers and stakeholders on the water, soil, and biodiversity resource and the landscape scale.

Emerging evidence indicates that microtubule-associated proteins (MAPs) are implicated in synaptic function; in particular, mice deficient for MAP6 exhibit striking deficits in plasticity and cognition. How MAP6 connects to plasticity mechanisms is unclear. Here, we address the possible role of this protein in dendritic spines. We find that in MAP6-deficient cortical and hippocampal neurons, maintenance of mature spines is impaired, and can be restored by expressing a stretch of the MAP6 sequence called Mc modules. Mc modules directly bind actin filaments and mediate activity-dependent stabilisation of F-actin in dendritic spines, a key event of synaptic plasticity. In vitro, Mc modules enhance actin filament nucleation and promote the formation of stable, highly ordered filament bundles. Activity-induced phosphorylation of MAP6 likely controls its transfer to the spine cytoskeleton. These results provide a molecular explanation for the role of MAP6 in cognition, enlightening the connection between cytoskeletal dysfunction, synaptic impairment and neuropsychiatric illnesses. Fil: Peris, Leticia. Universite Grenoble Alpes; Francia Fil: Bisbal, Mariano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; Argentina. Universite Grenoble Alpes; Francia Fil: Martinez Hernandez, José. Universidad del País Vasco; España. Universite Grenoble Alpes; Francia Fil: Saoudi, Yasmina. Universite Grenoble Alpes; Francia Fil: Jonckheere, Julie. Universite Grenoble Alpes; Francia Fil: Rolland, Marta. Universite Grenoble Alpes; Francia Fil: Sebastien, Muriel. Universite Grenoble Alpes; Francia Fil: Brocard, Jacques. Universite Grenoble Alpes; Francia Fil: Denarier, Eric. Universite Grenoble Alpes; Francia Fil: Bosc, Christopher. Universite Grenoble Alpes; Francia Fil: Guerin, Christophe. Universite Grenoble Alpes; Francia. Inserm; Francia Fil: Gory Fauré, Sylvie. Universite Grenoble Alpes; Francia Fil: Deloulme, Jean Christophe. Universite Grenoble Alpes; Francia Fil: Lanté, Fabien. Universite Grenoble Alpes; Francia Fil: Arnal, Isabelle. Universite Grenoble Alpes; Francia Fil: Buisson, Alain. Universite Grenoble Alpes; Francia Fil: Goldberg, Yves. Universite Grenoble Alpes; Francia Fil: Blanchoin, Laurent. Inserm; Francia. Universite Grenoble Alpes; Francia Fil: Delphin, Christian. Universite Grenoble Alpes; Francia Fil: Andrieux, Annie. Universite Grenoble Alpes; Francia

[Departement_IRSTEA]Eaux [TR1_IRSTEA]SEDYVIN [ADD1_IRSTEA]Adaptation des territoires au changement global [Departement_IRSTEA]Eaux [TR1_IRSTEA]SEDYVIN [ADD1_IRSTEA]Adaptation des territoires au changement global; International audience; The medium-high mountain ranges of Western Europe are undergoing rapid socio-environmental changes. The aim of this study is to show that their landscape can be strongly shaped by the actions of avalanche activity, humans and climate. The study area is the Rothenbachkopf-Rainkopf complex, a site representative of avalanche-prone areas of the Vosges Mountains (France). A geo-historical approach documents regular avalanche activity over more than 200 years on 13 paths. A diachronic analysis of historical maps and photographs demonstrates substantial afforestation (from 60 to 80% of the total surface since 1832). LIDAR data and field surveys highlight the existence of a longitudinal and transversal structure of trees. Hence, the avalanche, human and climate activity footprints are retained by the landscape, which rapidly adapts to these changing drivers. Specifically, the pattern of tree species and heights results from a near equilibrium with regular avalanche activity sometimes disturbed by major avalanches that induce quasi-cyclic changes in the landscape mosaic. The afforestation trend is attributable to profound changes in silvo-pastoral practices, supplemented by the impact of climate change. The wider relevance of the results in relation to the local context is discussed, as well as outlooks that can refine our understanding of this complex system.

[Departement_IRSTEA]Eaux [TR1_IRSTEA]ARCEAU [ADD1_IRSTEA]Hydrosystèmes et risques naturels [Departement_IRSTEA]Eaux [TR1_IRSTEA]ARCEAU [ADD1_IRSTEA]Hydrosystèmes et risques naturelsSpecial Section: Hydrological Observatories; International audience; The French critical zone initiative, called OZCAR (Observatoires de la Zone Critique-Application et Recherche or Critical Zone Observatories-Application and Research) is a National Research Infrastructure (RI). OZCAR-RI is a network of instrumented sites, bringing together 21 pre-existing research observatories monitoring different compartments of the zone situated between "the rock and the sky," the Earth's skin or critical zone (CZ), over the long term. These observatories are regionally based and have specific initial scientific questions, monitoring strategies, databases, and modeling activities. The diversity of OZCAR-RI observatories and sites is well representative of the heterogeneity of the CZ and of the scientific communities studying it. Despite this diversity, all OZCAR-RI sites share a main overarching mandate, which is to monitor, understand, and predict ("earthcast") the fluxes of water and matter of the Earth's near surface and how they will change in response to the "new climatic regime." The vision for OZCAR strategic development aims at designing an open infrastructure, building a national CZ community able to share a systemic representation of the CZ , and educating a new generation of scientists more apt to tackle the wicked problem of the Anthropocene. OZCAR articulates around: (i) a set of common scientific questions and cross-cutting scientific activities using the wealth of OZCAR-RI observatories, (ii) an ambitious instrumental development program, and (iii) a better interaction between data and models to integrate the different time and spatial scales. Internationally, OZCAR-RI aims at strengthening the CZ community by providing a model of organization for pre-existing observatories and by offering CZ instrumented sites. OZCAR is one of two French mirrors of the European Strategy Forum on Research Infrastructure (eLTER-ESFRI) project.

Background: Large observational implementation studies are needed to triangulate the findings from randomized control trials as they reflect “real-world” everyday practice. In a pilot study, we attempted to provide additional and complementary insights on the real-life treatment of allergic rhinitis (AR) using mobile technology. Methods: A mobile phone app (Allergy Diary, freely available in Google Play and Apple App stores) collects the data of daily visual analog scales (VAS) for (i) overall allergic symptoms, (ii) nasal, ocular, and asthma symptoms, (iii) work, as well as (iv) medication use using a treatment scroll list including all medications (prescribed and over the counter (OTC)) for rhinitis customized for 15 countries. Results: A total of 2871 users filled in 17 091 days of VAS in 2015 and 2016. Medications were reported for 9634 days. The assessment of days appeared to be more informative than the course of the treatment as, in real life, patients do not necessarily use treatment on a daily basis; rather, they appear to increase treatment use with the loss of symptom control. The Allergy Diary allowed differentiation between treatments within or between classes (intranasal corticosteroid use containing medications and oral H1-antihistamines). The control of days differed between no [best control], single, or multiple treatments (worst control). Conclusions: This study confirms the usefulness of the Allergy Diary in accessing and assessing everyday use and practice in AR. This pilot observational study uses a very simple assessment (VAS) on a mobile phone, shows novel findings, and generates new hypotheses. © 2018 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd.

– The research presented in this PhD thesis has as purpose to enrich the body of knowledge over thestudies of sustainability, by filling the gap between its definition and its use within a continuous improvementsframework. This thesis addresses, the issues associated with the sustainability of continuous improvementprograms, the possible reasoning behind that hurdle, a new interpretation of the term sustainability, theidentification of the elements that could characterize this definition, and the presentation of a maturity-benchmarkmodel formulated from the results of a self-assessment survey.A literature review and the PRISMA methodology were used to identify sustainability interpretations that werecategorized using different dimensions. With results from an exploratory research, this thesis also identifies a group of sixteen elements with the potentiality to characterize this sustainability. A self-assessment survey wasdesigned to evaluate such elements, by taking into account their deployment within an enhancement cycle in theform of PDCA. The findings show that in fact, sustainability itself has a series of paradoxes, especially whentransitioning it on a continuous improvement framework, in which it becomes a dynamic definition.Also, this thesis demonstrates how the elements identified are perceived, from the impact on sustainability in whichtwo large groups can be identified, those that are inclined to a more technical character and those that have a morenoticeable human interaction, and the way they are deployed in companies, where can be clearly seen, the fact thatthe stages Check and Act are less developed.One of the most important contributions in this thesis is the way in which the deployment of elements favouringthe sustainability of continuous improvement approaches can be approached within companies. To do this, thedesign of a positioning model, based on maturity, is proposed. It enables companies to assess the degree of maturityof their improvement initiatives and target areas that need particular vigilance., Résumé – La recherche présentée dans cette thèse de doctorat a pour but d'enrichir l’ensemble des connaissances sur les études de pérennité, en comblant l'écart entre sa définition et son utilisation dans un contexte d'amélioration continue. Cette thèse aborde les questions liées à la pérennisation des démarches d'amélioration continue : quelles sont les raisons qui expliquent les difficultés à la mise en œuvre d’une pérennisation ? en quoi une nouvelle interprétation du terme pérennité peut aider à la pérennisation des démarches d’amélioration continue ? quels sont les éléments qui, caractérisent cette définition ? et quel modèle de référence de maturité pouvons-nous proposer ? Une analyse bibliographique et l'utilisation de la méthodologie PRISMA ont été utilisées pour identifier les interprétations de la pérennité qui ont été catégorisées à l'aide de différentes dimensions. Avec les résultats d'une recherche exploratoire, cette thèse identifie également un groupe de seize éléments ayant le potentiel de caractériser cette pérennisation. Une enquête d'auto-évaluation a été conçue pour évaluer ces éléments, en tenant compte de leur déploiement au sein d'un cycle d'amélioration reprenant le cycle PDCA. Les résultats montrent que la pérennité elle-même présente une série de paradoxes. En particulier lorsqu'elle s’applique à un contexte d'amélioration continue, dans lequel une définition dynamique est nécessaire. Cette thèse montre également comment les éléments identifiés sont perçus, et plus particulièrement quel est leur impact sur la pérennité. Il est ainsi possible d’identifier deux grands groupes d’éléments : ceux qui ont un caractère plus technique et ceux qui ont une interaction humaine plus perceptible. De même, l’étude de la façon avec laquelle ces éléments sont déployés dans les entreprises, permet d’observer clairement que les étapes Check et Act de leur mise en œuvre en entreprise sont les étapes les moins développées.L'un des apports les plus importants dans cette thèse est la manière dont le déploiement des éléments favorisant la pérennisation des démarches d'amélioration continue peut-être abordé au sein des entreprises. Pour ce faire, la conception d'un modèle de positionnement, basé sur la maturité, est proposé. Il permet aux entreprises d'évaluer le degré de maturité de leurs initiatives d'amélioration et de cibler les éléments sur lesquels apporter une vigilance particulière.