Author: "EDF ( EDF )" - Searchworks@Jio Institute Digital Library Search Results

Your search keyword '"EDF ( EDF )"' showing total 7,072 results

Start Over Author "EDF ( EDF )"

7,072 results on '"EDF ( EDF )"'

1. Optimisation de l'analyse en champs de transformation non uniformes pour le comportement du combustible MOX en service.

Author: MMC ; EDF R&D ; EDF - EDF, Matériaux et Structures ; Laboratoire de Mécanique et d'Acoustique [Marseille] (LMA_CNRS) ; Ecole Centrale de Marseille - Aix Marseille Université - CNRS - Ecole Centrale de Marseille - Aix Marseille Université - CNRS, Matériaux et Structures ; Laboratoire de Mécanique et d'Acoustique (LMA) ; CNRS - CNRS - Laboratoire de Mécanique et d'Acoustique [Marseille] (LMA_CNRS) ; Ecole Centrale de Marseille - Aix Marseille Université - CNRS - Ecole Centrale de Marseille - Aix Marseille Université, Largenton, Rodrigue, Michel, Jean-Claude, Suquet, Pierre, MMC ; EDF R&D ; EDF - EDF, Matériaux et Structures ; Laboratoire de Mécanique et d'Acoustique [Marseille] (LMA_CNRS) ; Ecole Centrale de Marseille - Aix Marseille Université - CNRS - Ecole Centrale de Marseille - Aix Marseille Université - CNRS, Matériaux et Structures ; Laboratoire de Mécanique et d'Acoustique (LMA) ; CNRS - CNRS - Laboratoire de Mécanique et d'Acoustique [Marseille] (LMA_CNRS) ; Ecole Centrale de Marseille - Aix Marseille Université - CNRS - Ecole Centrale de Marseille - Aix Marseille Université, Largenton, Rodrigue, Michel, Jean-Claude, and Suquet, Pierre
Abstract: National audience, Le combustible nucléaire MOX ADU, irradié dans les réacteurs à eau pressurisée, est un composite particulaire triphasé. La modélisation de son comportement, viscoélastique linéaire vieillissant avec déformation libre, passe donc par la construction de lois macroscopiques faisant intervenir les effets microstructuraux. Pour homogénéiser ce comportement, la méthode par champs de transformation non uniformes NTFA avait été choisie, avec extension au 3D et prise en compte des déformations libres dans [1]. Les prédictions de ce modèle NTFA par rapport à des calculs de référence (Finite Element Method) étaient excellentes. Le modèle était également performant en temps de calcul (modèle à relativement faible nombre de variables internes). Néanmoins, du fait de la linéarité de notre comportement viscoélastique local, nous avons cherché à réduire le nombre de variables internes de ce modèle pour le rendre encore plus performant en temps d'exécution. Ces travaux sont exposés dans ce document.

2. Long-Term Tests and Advanced Post-Test Characterizations of the Oxygen Electrode in Solid Oxide Electrolysis Cells

Author: Celikbilek, Ozden, Sassone, Giuseppe, Prioux, Manon, Ferreira Sanchez, Dario, Benayad, Anass, Hubert, Maxime, Morel, Bertrand, Vulliet, Julien, Léon, Aline, Laurencin, Jérôme, ARC-Nucleart CEA Grenoble (NUCLEART), Laboratoire d'Innovation pour les Technologies des Energies Nouvelles et les nanomatériaux (LITEN), Institut National de L'Energie Solaire (INES), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de L'Energie Solaire (INES), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Département Technique Conversion et Hydrogène (DTCH), Paul Scherrer Institute (PSI), Département des Technologies des NanoMatériaux (DTNM), CEA Le Ripault (CEA Le Ripault), Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), European Institute For Energy Research (EIFER), Universität Karlsruhe (TH)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), ANR-22-PEHY-0008,CELCER-EHT,Ceramic Cells for durable performant and cost efficient HTE(2022), and European Project: 874577,NewSOC
Subjects: [SPI]Engineering Sciences [physics], General Medicine
Abstract: International audience; Solid oxide electrolysis cells (SOEC) are a promising energy conversion technology for the production of green hydrogen via steam electrolysis. However, performance loss remains a bottleneck for large-scale commercialization. Here, we investigate the different types of degradation occurring in a state-of-the-art cell composed of La0.6Sr0.4Co0.2Fe0.8O3-Ce0.8Gd0.2O2 (LSCF-GDC) composite for the oxygen electrode, GDC for the barrier layer, Y0.16Zr0.84O1.92 (8YSZ) for the electrolyte and Ni-YSZ for the fuel electrode. Electrochemical impedance spectra measured before and after operation at 750 °C for 2000 hours at -1 A cm-2 in SOEC mode revealed no significant evolution for the oxygen electrode contribution. To investigate potential degradation of this electrode, we performed multi-modal chemical imaging based on synchrotron X-ray diffraction (µ-XRD) with a resolution at the micrometer-scale. In addition, we monitored the evolution of the chemical composition and chemical environment before and after ageing using laboratory X-ray photoelectron spectroscopy (XPS). All these analyses revealed a slight evolution of the crystal lattice parameter in the oxygen electrode and the inter-diffusion layer. It was also found that Sr segregation accelerates with ageing. However, more severe ageing conditions and/or longer ageing durations are required in order to observe an effect on the performance.
Published: 2023

3. Accounting for meteorological biases in simulated plumes using smarter metrics

Author: Pierre J. Vanderbecken, Joffrey Dumont Le Brazidec, Alban Farchi, Marc Bocquet, Yelva Roustan, Élise Potier, Grégoire Broquet, Centre d'Enseignement et de Recherche en Environnement Atmosphérique (CEREA), École des Ponts ParisTech (ENPC)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Modélisation INVerse pour les mesures atmosphériques et SATellitaires (SATINV), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), This study has been funded by the national research project ANR-ARGONAUT no. ANR-19-CE01-0007 (PollutAnts and gReenhouse Gases emissiOns moNitoring from spAce at high ResolUTion). Joffrey Dumont Le Brazidec is supported by the European Union's Horizon 2020 research and innovation programme under grant agreement no. 958927 (Prototype system for a Copernicus CO2service). All the figures were drawn using CVD-friendly colour maps. This was made possible using a Python wrapper around Fabio Crameri's perceptually uniform colour maps , available here: https://www.fabiocrameri.ch/colourmaps/ (last access: 14 March 2023). CEREA is a member of Institut Pierre-Simon Laplace (IPSL). The authors jointly thank the associate editor, Lok Lamsal, and the two anonymous referees for the relevant comments they made during the review of this article., and ANR-19-CE01-0007,ARGONAUT,Suivi des émissions de polluants et de gaz à effet de serre à haute résolution depuis l'espace(2019)
Subjects: Atmospheric Science, plume, image analysis, [SDU]Sciences of the Universe [physics], emission, satellite, environmental modeling, meteorology, simulation
Abstract: In the next few years, numerous satellites with high-resolution instruments dedicated to the imaging of atmospheric gaseous compounds will be launched, to finely monitor emissions of greenhouse gases and pollutants. Processing the resulting images of plumes from cities and industrial plants to infer the emissions of these sources can be challenging. In particular traditional atmospheric inversion techniques, relying on objective comparisons to simulations with atmospheric chemistry transport models, may poorly fit the observed plume due to modelling errors rather than due to uncertainties in the emissions. The present article discusses how these images can be adequately compared to simulated concentrations to limit the weight of modelling errors due to the meteorology used to analyse the images. For such comparisons, the usual pixel-wise ℒ2 norm may not be suitable, since it does not linearly penalise a displacement between two identical plumes. By definition, such a metric considers a displacement as an accumulation of significant local amplitude discrepancies. This is the so-called double penalty issue. To avoid this issue, we propose three solutions: (i) compensate for position error, due to a displacement, before the local comparison; (ii) use non-local metrics of density distribution comparison; and (iii) use a combination of the first two solutions. All the metrics are evaluated using first a catalogue of analytical plumes and then more realistic plumes simulated with a mesoscale Eulerian atmospheric transport model, with an emphasis on the sensitivity of the metrics to position error and the concentration values within the plumes. As expected, the metrics with the upstream correction are found to be less sensitive to position error in both analytical and realistic conditions. Furthermore, in realistic cases, we evaluate the weight of changes in the norm and the direction of the four-dimensional wind fields in our metric values. This comparison highlights the link between differences in the synoptic-scale winds direction and position error. Hence the contribution of the latter to our new metrics is reduced, thus limiting misinterpretation. Furthermore, the new metrics also avoid the double penalty issue.
Published: 2023

4. Un algorithme de calcul de trajectoires de particules au sein de maillages 3D non-structurés robuste en pas de temps pour des approches lagrangiennes stochastiques

Author: Guilhem Balvet, Jean-Pierre Minier, Christophe Henry, Yelva Roustan, Martin Ferrand, Mécanique des Fluides, Energies et Environnement (EDF R&D MFEE), EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Centre d'Enseignement et de Recherche en Environnement Atmosphérique (CEREA), École des Ponts ParisTech (ENPC)-EDF R&D (EDF R&D), Université Côte d’Azur, Inria, CNRS, Sophia Antipolis, France, and financial support by ANRT through the EDF-CIFRE contract number 2020/1387
Subjects: FOS: Computer and information sciences, Statistics and Probability, temporal integration, Applied Mathematics, Lagrangian stochastic modeling particle-mesh PDF temporal integration trajectory in 3-D unstructured mesh time-splitting methods anticipation error, Classical Physics (physics.class-ph), FOS: Physical sciences, Physics - Classical Physics, trajectory in 3-D unstructured mesh, Statistics - Computation, time-splitting methods, [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph], Lagrangian stochastic modeling, particle-mesh PDF, Computation (stat.CO), anticipation error
Abstract: International audience; The purpose of this paper is to propose a time-step-robust cell-to-cell integration of particle trajectories in 3-D unstructured meshes in particle/mesh Lagrangian stochastic methods. The main idea is to dynamically update the mean fields used in the time integration by splitting, for each particle, the time step into sub-steps such that each of these sub-steps corresponds to particle cell residence times. This reduces the spatial discretization error. Given the stochastic nature of the models, a key aspect is to derive estimations of the residence times that do not anticipate the future of the Wiener process. To that effect, the new algorithm relies on a virtual particle, attached to each stochastic one, whose mean conditional behavior provides free-of-statistical-bias predictions of residence times. After consistency checks, this new algorithm is validated on two representative test cases: particle dispersion in a statistically uniform flow and particle dynamics in a non-uniform flow.; L’objectif de ce papier est de proposer un algorithme robuste en pas de temps permettant l’intégration face à face de la trajectoire de particules dans des maillage 3-D non-structurés pour des méthodes lagrangiennes stochastiques. L’idée principale est de mettre à jour de façon dynamique les champs moyens utilisés dans l’intégration temporelle. Pour ce faire, pour chaque particule, on subdivise le pas de temps en sous pas de temps, de façon à ce que chacun de ceux-ci correspondent au temps de résidence de la particule dans une cellule. Ce faisant on réduit l’erreur de discrétisation spatiale. Étant donnée la nature stochastique du modèle, un aspect prépondérant est de pouvoir dériver des estimations du temps de résidence des particules dans les cellules qui n’anticipent pas le futur des processus de Wiener. Dans ce but, le nouvel algorithme est basé sur une particule virtuelle attachée à chaque particule stochastique, dont le comportement conditionné moyen permet d’obtenir des temps de résidence qui ne sont entachés d’aucun biais statistique. Après une vérification de consistance, ce nouvel algorithme est validé sur deux cas de tests représentatifs : une dispersion de polluants dans un écoulement statistiquement uniforme et un écoulement non-uniforme dans lequel on traque la dynamique des particules.
Published: 2023

5. Numerical Investigations of a Two-Way Coupled Fluid–Structure Interaction Approach for Fast Transients in Fluid-Filled Flexible Piping Systems

Author: Daude, Frédéric, Galon, Pascal, Shams, Afaque, Institut des Sciences de la mécanique et Applications industrielles (IMSIA - UMR 9219), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École Nationale Supérieure de Techniques Avancées (ENSTA Paris)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), ElectRotechnique et MEcanique des Structures (EDF R&D ERMES), EDF R&D (EDF R&D), CEA- Saclay (CEA), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: [PHYS.MPHY]Physics [physics]/Mathematical Physics [math-ph]
Abstract: International audience
Published: 2023

6. A viscoelastic flow model of Maxwell-type with a symmetric-hyperbolic formulation

Author: Boyaval, Sébastien, Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (LHSV), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), MATHematics for MatERIALS (MATHERIALS), Centre d'Enseignement et de Recherche en Mathématiques et Calcul Scientifique (CERMICS), École des Ponts ParisTech (ENPC)-École des Ponts ParisTech (ENPC)-Inria de Paris, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), and ANR-15-CE01-0013,SEDIFLO,Modélisation et simulation du transport solide en rivières(2015)
Subjects: Mechanics of Materials, FOS: Mathematics, General Materials Science, Mathematics - Numerical Analysis, Numerical Analysis (math.NA), [MATH.MATH-NA]Mathematics [math]/Numerical Analysis [math.NA]
Abstract: Maxwell models for viscoelastic flows are famous for their potential to unify elastic motions of solids with viscous motions of liquids in the continuum mechanics perspective. But the usual Maxwell models allow one to define well motions mostly for one-dimensional flows only. To define unequivocal multi-dimensional viscoelastic flows (as solutions to well-posed initial-value problems) we advocated in [ESAIM:M2AN 55 (2021) 807-831] an upper-convected Maxwell model for compressible flows with a symmetrichyperbolic formulation. Here, that model is derived again, with new details.
Published: 2023

7. Nonatomic aggregative games with infinitely many types

Author: Paulin Jacquot, Cheng Wan, Centre de Mathématiques Appliquées - Ecole Polytechnique (CMAP), École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), TROPICAL (TROPICAL), École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS)-Inria Saclay - Ile de France, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Optimisation, Simulation, Risque et Statistiques pour les Marchés de l’Energie (EDF R&D OSIRIS), EDF R&D (EDF R&D), and EDF (EDF)-EDF (EDF)
Subjects: FOS: Computer and information sciences, TheoryofComputation_MISCELLANEOUS, Computer Science::Computer Science and Game Theory, Information Systems and Management, General Computer Science, media_common.quotation_subject, 0211 other engineering and technologies, Monotonic function, 02 engineering and technology, Management Science and Operations Research, generalized variational inequality, Industrial and Manufacturing Engineering, nonatomic aggregative game, Computer Science - Computer Science and Game Theory, 0502 economics and business, Convergence (routing), FOS: Mathematics, 050207 economics, Mathematics - Optimization and Control, Finite set, Parametric statistics, Mathematics, media_common, Sequence, 021103 operations research, 05 social sciences, ComputingMilieux_PERSONALCOMPUTING, TheoryofComputation_GENERAL, Coupling (probability), Infinity, Optimization and Control (math.OC), variational equilibrium, Modeling and Simulation, Variational inequality, [MATH.MATH-OC]Mathematics [math]/Optimization and Control [math.OC], [INFO.INFO-DC]Computer Science [cs]/Distributed, Parallel, and Cluster Computing [cs.DC], coupling aggregative constraints, Mathematical economics, monotone game, Computer Science and Game Theory (cs.GT)
Abstract: We define and analyze the notion of variational Wardrop equilibrium for nonatomic aggregative games with an infinity of players types. These equilibria are characterized through an infinite-dimensional variational inequality. We show, under monotonicity conditions, a convergence theorem enables to approximate such an equilibrium with arbitrary precision. To this end, we introduce a sequence of nonatomic games with a finite number of players types, which approximates the initial game. We show the existence of a symmetric Wardrop equilibrium in each of these games. We prove that those symmetric equilibria converge to an equilibrium of the infinite game, and that they can be computed as solutions of finite-dimensional variational inequalities. The model is illustrated through an example from smart grids: the description of a large population of electricity consumers by a parametric distribution gives a nonatomic game with an infinity of different players types, with actions subject to coupling constraints., arXiv admin note: substantial text overlap with arXiv:1806.06230
Published: 2022

8. Assessment of one-way coupling methods from a potential to a viscous flow solver based on domain- and functional-decomposition for fixed submerged bodies in nonlinear waves

Author: Michel Benoit, Fabien Robaux, Institut de Recherche sur les Phénomènes Hors Equilibre (IRPHE), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (LHSV), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), École Centrale de Marseille (ECM), Laboratoire National d’Hydraulique et Environnement (EDF R&D LNHE), and EDF R&D (EDF R&D)
Subjects: Physics::Fluid Dynamics, Fluid-structure interaction, Potential-viscous coupling, Functional decomposition, Fluid Dynamics (physics.flu-dyn), FOS: Physical sciences, General Physics and Astronomy, Physics - Fluid Dynamics, Domain decomposition, [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph], Nonlinear water waves, Coupling methods, Mathematical Physics
Abstract: To simulate the interaction of ocean waves with marine structures, coupling approaches between a potential flow model and a viscous model are investigated. The first model is a fully nonlinear potential flow (FNPF) model based on the Harmonic Polynomial Cell (HPC) method, which is highly accurate and best suited for representing long distance wave propagation. The second model is a CFD code, solving the Reynolds-Averaged Navier-Stokes (RANS) equations within the \openfoam toolkit, more suited to represent viscous and turbulent effects at local scale in the body vicinity. Two one-way coupling strategies are developed and compared in two dimensions, considering fully submerged and fixed structures. A domain decomposition (DD) strategy is first considered, introducing a refined mesh in the body vicinity on which the RANS equations are solved. Boundary conditions and interpolation operators from the FNPF results are developed in order to enforce values at its outer boundary. The second coupling strategy considers a decomposition of variables (functional decomposition, FD) on the local grid. As the FNPF simulation provides fields of variables satisfying the irrotational Euler equations, complementary velocity and pressure components are introduced as the difference between the total flow variables and the potential ones. Those complementary variables are solutions of modified RANS equations. Comparisons are presented for nonlinear waves interacting with a horizontal cylinder of rectangular cross-section. The loads exerted on the body computed from the four simulation methods (standalone FNPF, standalone CFD, DD and FD coupling schemes) are compared with experimental data. It is shown that both coupling approaches produce an accurate representation of the loads and associated hydrodynamic coefficients over a large range of incident wave steepness and Keulegan-Carpenter number., Comment: 39 Pages, 12 figures, 2 tables
Published: 2022

9. Stable schemes for second-moment turbulent models for incompressible flows

Author: Ferrand, Martin, Hérard, Jean-Marc, Norddine, Thomas, Ruget, Simon, Centre d'Enseignement et de Recherche en Environnement Atmosphérique (CEREA), École des Ponts ParisTech (ENPC)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), EDF R&D (EDF R&D), EDF (EDF), Institut de Mathématiques de Marseille (I2M), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), and École des Ponts ParisTech (ENPC)
Subjects: second-moment turbulent closure, [MATH.MATH-AP]Mathematics [math]/Analysis of PDEs [math.AP], [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph], hyperbolic systems, Riemann problem, incompressible turbulent flows
Abstract: International audience; A stable scheme is proposed in this paper in order to obtain approximate solutions of second-moment turbulent models for incompressible flows with or without thermal transport equation. The analysis of the convective terms, which includes the solution of the associated Riemann problem, enables to propose a standard projection scheme, and to get rid of spurious oscillations.
Published: 2023

10. Intercalated Organic Redox-active Anions for Enhanced Capacity of Layered Double Hydroxides

Author: Gerlach, Patrick, Douard, Camille, Gaalich, Insaf, Athouël, Laurence, Sarmet, Julien, Leroux, Fabrice, Tavoit-Gueho, Christine, Stevens, Philippe, Toussaint, Gwenaëlle, Brousse, Thierry, Institut des Matériaux Jean Rouxel (IMN), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Nantes université - UFR des Sciences et des Techniques (Nantes univ - UFR ST), Nantes Université - pôle Sciences et technologie, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ)-Nantes Université - pôle Sciences et technologie, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ)-Nantes Université - Ecole Polytechnique de l'Université de Nantes (Nantes Univ - EPUN), Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ), Réseau sur le stockage électrochimique de l'énergie (RS2E), Aix Marseille Université (AMU)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Collège de France (CdF (institution))-Université de Picardie Jules Verne (UPJV)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Pau et des Pays de l'Adour (UPPA)-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA)-Nantes Université (Nantes Univ)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM), Université de Montpellier (UM), Institut de Chimie de Clermont-Ferrand (ICCF), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Institut national polytechnique Clermont Auvergne (INP Clermont Auvergne), Université Clermont Auvergne (UCA)-Université Clermont Auvergne (UCA), Laboratoire des Matériels Électriques (EDF R&D LME), EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), EDF (EDF), ANR-20-CE05-0024,LaDHy,hydroxydes lamellaires pour systèmes de stockage innovants(2020), and ANR-10-LABX-0076,STORE-EX,Laboratory of excellency for electrochemical energy storage(2010)
Subjects: [CHIM]Chemical Sciences
Abstract: International audience; A Layered Double Hydroxide (LDH) compound LDH ([Mg 2 Al(OH) 6 ] + x 2 H 2 O) intercalated with a redox active organic anion, Anthraquinone-2-sulfonate (AQS), has been envisioned as an electrode material for high power aqueous based battery. The purpose is to use this interlayer redox active molecule for the enhancement of the specific capacity at the LDH composite electrode, which should allow fast charge transfer at the negative electrode for high power storage applications. This is achieved by the reduction of AQS in charge and oxidation in discharge within a redox inactive LDH matrix. The first charge of this new material [Mg 2 Al(OH) 6 ] + [AQSO 3 ] − x 2 H 2 O leads to a capacity of 100 mAh g −1 at − 0.78 V vs Ag/AgCl (based on the weight of the active material) when operated in aqueous 1 M sodium acetate electrolyte. However, low cycling stability was observed, since a drastic loss in specific capacity occurs after the first charge. This study focuses at elucidating the mechanism behind this phenomenon via in situ UV/vis experiments. Subsequently, the dissolution of charged AQS anions into the electrolyte during the first charge of the anode has been identified and quantified. Such understanding of fading mechanism might lead to the design of improved LDH-based electrodes, which utilize redox active anions working in the positive potential range with enhanced cycling ability.
Published: 2023

11. Training Deep Surrogate Models with Large Scale Online Learning

Author: Meyer, Lucas, Schouler, Marc, Caulk, Robert Alexander, Ribés, Alejandro, Raffin, Bruno, EDF R&D (EDF R&D), EDF (EDF), Saclay Industrial Lab for Artificial Intelligence Research (SINCLAIR AI Lab), THALES [France]-TOTAL FINA ELF-EDF (EDF), Data Aware Large Scale Computing (DATAMOVE ), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire d'Informatique de Grenoble (LIG), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), and European Project: 956560,REGALE
Subjects: FOS: Computer and information sciences, Online Deep Learning, Large Scale Dataset, Computer Science - Artificial Intelligence, High Performance Computing, FOS: Physical sciences, Partial Differential Equations, Computational Physics (physics.comp-ph), Numerical Simulations, [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation, Surrogate Models, [INFO.INFO-AI]Computer Science [cs]/Artificial Intelligence [cs.AI], Synthetic Data, [PHYS.PHYS.PHYS-COMP-PH]Physics [physics]/Physics [physics]/Computational Physics [physics.comp-ph], Artificial Intelligence (cs.AI), Training Framework, Computer Science - Distributed, Parallel, and Cluster Computing, Distributed, Parallel, and Cluster Computing (cs.DC), [INFO.INFO-DC]Computer Science [cs]/Distributed, Parallel, and Cluster Computing [cs.DC], Physics - Computational Physics
Abstract: The spatiotemporal resolution of Partial Differential Equations (PDEs) plays important roles in the mathematical description of the world's physical phenomena. In general, scientists and engineers solve PDEs numerically by the use of computationally demanding solvers. Recently, deep learning algorithms have emerged as a viable alternative for obtaining fast solutions for PDEs. Models are usually trained on synthetic data generated by solvers, stored on disk and read back for training. This paper advocates that relying on a traditional static dataset to train these models does not allow the full benefit of the solver to be used as a data generator. It proposes an open source online training framework for deep surrogate models. The framework implements several levels of parallelism focused on simultaneously generating numerical simulations and training deep neural networks. This approach suppresses the I/O and storage bottleneck associated with disk-loaded datasets, and opens the way to training on significantly larger datasets. Experiments compare the offline and online training of four surrogate models, including state-of-the-art architectures. Results indicate that exposing deep surrogate models to more dataset diversity, up to hundreds of GB, can increase model generalization capabilities. Fully connected neural networks, Fourier Neural Operator (FNO), and Message Passing PDE Solver prediction accuracy is improved by 68%, 16% and 7%, respectively.
Published: 2023

12. Reduced order modeling of rotating structures featuring geometric nonlinearity with the direct parametrisation of invariant manifolds method

Author: Martin, Adrien, Opreni, Andrea, Vizzaccaro, Alessandra, Salles, Loic, Thomas, Olivier, Frangi, Attilio, Touzé, Cyril, Institut des Sciences de la mécanique et Applications industrielles (IMSIA - UMR 9219), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École Nationale Supérieure de Techniques Avancées (ENSTA Paris)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), École Nationale Supérieure de Techniques Avancées (ENSTA Paris), Institut Polytechnique de Paris (IP Paris), Politecnico di Milano [Milan] (POLIMI), University of Bristol [Bristol], Département d’Aérospatiale et de Mécanique [Liège], Université de Liège, HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM), and Sapienza, Universita di Roma
Subjects: [SPI.MECA.VIBR]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Vibrations [physics.class-ph], Reduced order Model, invariant manifold, geometric nonlinearity, rotating structure
Abstract: International audience; The direct parametrisation method for invariant manifolds (DPIM) is applied to rotating structures. Reduced- order models of arbitrary order expansion can be derived for non-autonomous systems of nonlinear differential equations stemming from finite element models of continuous structures. The method is applied to a rotating simplified fan blade with comparisons to full order model simulations.
Published: 2023

13. The ecological causes of functional distinctiveness in communities

Author: Munoz, François, Klausmeier, Christopher A, Gaüzère, Pierre, Kandlikar, Gaurav, Litchman, Elena, Mouquet, Nicolas, Ostling, Annette, Thuiller, Wilfried, Algar, Adam C, Auber, Arnaud, Cadotte, Marc W, Delalandre, Léo, Denelle, Pierre, Enquist, Brian J, Fortunel, Claire, Grenié, Matthias, Loiseau, Nicolas, Mahaut, Lucie, Maire, Anthony, Mouillot, David, Pimiento, Catalina, Violle, Cyrille, Kraft, Nathan J B, Laboratoire Interdisciplinaire de Physique [Saint Martin d’Hères] (LIPhy ), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Michigan State University [East Lansing], Michigan State University System, Laboratoire d'Ecologie Alpine (LECA ), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), University of Missouri [Columbia] (Mizzou), University of Missouri System, Laboratoire Service d' Experimentations Aquacoles [Palavas les Flots] (LSEA MARBEC), MARine Biodiversity Exploitation and Conservation (UMR MARBEC), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM), University of Texas at Austin [Austin], Laboratoire Environnement de Conception & Architecture (LECA), Université Paris-Saclay-Département Systèmes et Circuits Intégrés Numériques (DSCIN), Laboratoire d'Intégration des Systèmes et des Technologies (LIST (CEA)), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Laboratoire d'Intégration des Systèmes et des Technologies (LIST (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Lakehead University, Laboratoire Ressources Halieutiques (LRH), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), University of Toronto at Scarborough, Centre d’Ecologie Fonctionnelle et Evolutive (CEFE), Université Paul-Valéry - Montpellier 3 (UPVM)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut Agro Montpellier, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Université de Montpellier (UM), Georg-August-University = Georg-August-Universität Göttingen, University of Arizona, Botanique et Modélisation de l'Architecture des Plantes et des Végétations (UMR AMAP), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université de Montpellier (UM), German Centre for Integrative Biodiversity Research (iDiv), Centre de Synthèse et d’Analyse sur la Biodiversité (CESAB), Fondation pour la recherche sur la Biodiversité (FRB), Laboratoire National d’Hydraulique et Environnement (EDF R&D LNHE), EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Universität Zürich [Zürich] = University of Zurich (UZH), University of California (UC), University of Zurich, and Munoz, François
Subjects: Ecology, source, Evolution, Community assembly, Fitness landscape, 10125 Paleontological Institute and Museum, 1105 Ecology, Evolution, Behavior and Systematics, 560 Fossils & prehistoric life, Behavior and Systematics, [SDE]Environmental Sciences, Source-sink dynamics, sink dynamics, Coexistence, Ecological interactions, Functional traits
Abstract: International audience; Recent work has shown that evaluating functional trait distinctiveness, the average trait distance of a species to other species in a community offers promising insights into biodiversity dynamics and ecosystem functioning. However, the ecological mechanisms underlying the emergence and persistence of functionally distinct species are poorly understood. Here, we address the issue by considering a heterogeneous fitness landscape whereby functional dimensions encompass peaks representing trait combinations yielding positive population growth rates in a community. We identify four ecological cases contributing to the emergence and persistence of functionally distinct species. First, environmental heterogeneity or alternative phenotypic designs can drive positive population growth of functionally distinct species. Second, sink populations with negative population growth can deviate from local fitness peaks and be functionally distinct. Third, species found at the margin of the fitness landscape can persist but be functionally distinct. Fourth, biotic interactions (positive or negative) can dynamically alter the fitness landscape. We offer examples of these four cases and guidelines to distinguish between them. In addition to these deterministic processes, we explore how stochastic dispersal limitation can yield functional distinctiveness. Our framework offers a novel perspective on the relationship between fitness landscape heterogeneity and the functional composition of ecological assemblages.
Published: 2023

14. LEARNING FUNCTIONS DEFINED OVER SETS OF VECTORS WITH KERNEL METHODS

Author: Sow, Babacar, Le Riche, Rodolphe, Pelamatti, Julien, Zannane, Sanaa, Keller, Merlin, Laboratoire d'Informatique, de Modélisation et d'Optimisation des Systèmes (LIMOS), Ecole Nationale Supérieure des Mines de St Etienne (ENSM ST-ETIENNE)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Institut national polytechnique Clermont Auvergne (INP Clermont Auvergne), Université Clermont Auvergne (UCA)-Université Clermont Auvergne (UCA), École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT), Institut Henri Fayol (FAYOL-ENSMSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Département Génie mathématique et industriel (FAYOL-ENSMSE), Ecole Nationale Supérieure des Mines de St Etienne (ENSM ST-ETIENNE)-Institut Henri Fayol, Centre National de la Recherche Scientifique (CNRS), EDF R&D (EDF R&D), EDF (EDF), Management des Risques Industriels (EDF R&D MRI), and EDF (EDF)-EDF (EDF)
Subjects: Surrogate models, Clouds of points, Sets of vectors, [MATH]Mathematics [math], Gaussian process, Semi-definite positive kernel, [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation
Abstract: International audience; We consider the problem of learning time-consuming functions defined over unordered sets of vectors. Such functions arise frequently, in particular in the context of networks of devices whose number is not fixed and that interact with each other. A working example is the modeling of a wind farm. Unordered sets of vectors are a mix of integer and continuous input variables suitable for functions that are permutation-invariant. The time-consuming aspect of the functions is, classically, treated by approximating them with a Gaussian process.This study addresses the problem of defining valid and efficient covariance kernels over cloudsof points in the context of Gaussian process surrogate modeling. We review methods for defining such kernels. These kernels are compared on a set of analyticalfunctions inspired from different engineering problems, such as the design of experiments andthe modeling of wind farms production. The extrapolation properties of the kernels are testedon geometrically transformed clouds.We show that modeling 2D clouds of points as supports of discrete uniform distributions should be preferred to a Gaussian representation of the clouds. A detailed investigation of the good performance of MMD-based kernels illustrates how they adapt their hyperparameters to the geometrical properties of the studied functions.
Published: 2023

15. Reduced-order modeling of geometrically nonlinear rotating structures using the direct parametrisation of invariant manifolds

Author: Martin, Adrien, Opreni, Andrea, Vizzaccaro, Alessandra, Debeurre, Marielle, Salles, Loic, Frangi, Attilio, Thomas, Olivier, Touzé, Cyril, Institut des Sciences de la mécanique et Applications industrielles (IMSIA - UMR 9219), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École Nationale Supérieure de Techniques Avancées (ENSTA Paris)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), École Nationale Supérieure de Techniques Avancées (ENSTA Paris), Institut Polytechnique de Paris (IP Paris), Politecnico di Milano [Milan] (POLIMI), University of Bristol [Bristol], Laboratoire d’Ingénierie des Systèmes Physiques et Numériques (LISPEN), Arts et Métiers Sciences et Technologies, HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM), HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM), Imperial College London, and Université de Liège
Subjects: [PHYS.MECA.VIBR]Physics [physics]/Mechanics [physics]/Vibrations [physics.class-ph], rotating structure, [PHYS.MECA.STRU]Physics [physics]/Mechanics [physics]/Structural mechanics [physics.class-ph], nonlinear normal modes, invariant manifold, geometric nonlinearity
Abstract: International audience; The direct parametrisation method for invariant manifolds is a nonlinear reduction technique which derives nonlinear mappings and reduced-order dynamics that describe the evolution of dynamical systems along a low-dimensional invariant-based span of the phase space. It can be directly applied to finite element problems. When the development is performed using an arbitrary order asymptotic expansion, it provides an efficient reduced-order modeling strategy for geometrically nonlinear structures. It is here applied to the case of rotating structures featuring centrifugal effect. A rotating cantilever beam with large amplitude vibrations is first selected in order to highlight the main features of the method. Numerical results show that the method provides accurate reduced-order models (ROMs) for any rotation speed and vibration amplitude of interest with a single master mode, thus offering remarkable reduction in the computational burden. The hardening/softening transition of the fundamental flexural mode with increasing rotation speed is then investigated in detail and a ROM parametrised with respect to rotation speed and forcing frequencies is detailed. The method is then applied to a twisted plate model representative of a fan blade, showing how the technique can handle more complex structures. Hardening/softening transition is also investigated as well as interpolation of ROMs, highlighting the efficacy of the method.
Published: 2023

16. Melissa: coordinating large-scale ensemble runs for deep learning and sensitivity analyses

Author: Schouler, Marc, Caulk, Robert Alexander, Meyer, Lucas, Terraz, Théophile, Conrads, Christoph, Friedemann, Sebastian, Agarwal, Achal, Baldonado, Juan Manuel, Pogodziński, Bartłomiej, Sekuła, Anna, Ribes, Alejandro, Raffin, Bruno, Data Aware Large Scale Computing (DATAMOVE ), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire d'Informatique de Grenoble (LIG), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), EDF R&D (EDF R&D), EDF (EDF), Saclay Industrial Lab for Artificial Intelligence Research (SINCLAIR AI Lab), THALES [France]-TOTAL FINA ELF-EDF (EDF), Institute of Bioorganic Chemistry [Poznań], Polska Akademia Nauk = Polish Academy of Sciences (PAN), European Project: 956560,REGALE, and European Project: 824158,H2020-EU.1.4. - EXCELLENT SCIENCE - Research Infrastructures ,EoCoE-II(2019)
Subjects: distributed systems, [PHYS]Physics [physics], [STAT]Statistics [stat], Supercomputing, Surrogate Modeling, Deep learning, Orchestration Framework, [INFO]Computer Science [cs], Sensitivity analysis
Abstract: International audience; Large-scale ensemble runs typically consist of executing thousands of physical simulation instances according to a range of different input parameters. These ensemble runs enable sensitivity analyses, deep surrogate trainings, reinforcement learning, and data assimilation, but they rely on volumes of data that are too large to store. For example, a recent data assimilation ensemble study generated 1.3 PB of data [@yashiro2020]. These enormous volumes of data hinder scientific analyses in two ways: first, the I/O speeds are the slowest component in supercomputers; the incongruence between slow read/write speeds compared to the rapid generation of data leads to a degradation and plateau of performance. Second, the file systems on supercomputers are not designed to allocate such large volumes of data to singular studies. To avoid this I/O limitation, scientists reduce their study size by running low resolution simulations or down-sampling output data in space and time. However, the I/O problem only becomes more pronounced as the speed and size of supercomputers continues to advance faster than I/O speeds of storage disks.
Published: 2023

17. Stable GSTC Formulation for Maxwell’s Equations

Author: Nicolas Lebbe, Kim Pham, Agnes Maurel, Université Côte d'Azur (UCA), Centre National de la Recherche Scientifique (CNRS), Modélisation et méthodes numériques pour le calcul d'interactions onde-matière nanostructurée (ATLANTIS), Inria Sophia Antipolis - Méditerranée (CRISAM), Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Alexandre Dieudonné (JAD), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS)-Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la mécanique et Applications industrielles (IMSIA - UMR 9219), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École Nationale Supérieure de Techniques Avancées (ENSTA Paris)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Institut Langevin - Ondes et Images (UMR7587) (IL), Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Université Paris sciences et lettres (PSL), Nicolas Lebbe acknowledge support from French defence procurement agency under the ANR ASTRID Maturation program, grant agreement number ANR-18-ASMA-0006-01. Kim Pham acknowledges support from the Agence de l’Innovation de Défense (AID) from the Direction Générale de l’Armement (DGA), under grant n° 2019 65 0070 and the Agence Nationale de la Recherche under grant ANR-19-CE08-0006., ANR-18-ASMA-0006,OPERA,Optique planaire adaptative(2018), ANR-19-CE08-0006,METARESO,Propagation d'ondes dans des Métamatériaux Résonants(2019), Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Alexandre Dieudonné (LJAD), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS)-Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS)-Université Côte d'Azur (UCA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École Nationale Supérieure de Techniques Avancées (ENSTA Paris)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-EDF R&D (EDF R&D), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], Asymptotic analysis, Metafilms, [PHYS.MPHY]Physics [physics]/Mathematical Physics [math-ph], Metasurface, Numerical implementation of the enlarged GSTCs, Electrical and Electronic Engineering, Generalized sheet transition conditions (GSTC), Two-scale homogenization technique
Abstract: We revisit the classical zero-thickness Generalized Sheet Transition Conditions (GSTCs) which are a key tool for efficiently designing metafilms able to control the flow of light in a desired way. It is shown that it is more convenient to use an enlarged formulation of the GSTC in which the original metafilm is replaced by GSTCs that exclude the layer from the physical or computational domain. These new "layer" transition conditions have the same form as their "sheet" analogues hence they do not necessitate additional complications in their use; their advantage is that they provide a well-posed problem hence guaranty the stability of numerical schemes in the timedomain. These assessments are demonstrated for an all-dielectric structure; the effective susceptibility tensors are derived thanks to asymptotic analysis combined with homogenization technique and bounds for the susceptibilities entering the balance of energy are provided. While negative constant susceptibilities appear in the classical zero-thickness GSTCs, their values in the enlarged formulation are always positive which ensure the stability of the effective problem. Validation of the effective model is provided by means of comparison with direct numerics in two and three dimensions.
Published: 2022

18. Influence of emission size distribution and nucleation on number concentrations over Greater Paris

Author: Karine Sartelet, Youngseob Kim, Florian Couvidat, Maik Merkel, Tuukka Petäjä, Jean Sciare, Alfred Wiedensohler, Centre d'Enseignement et de Recherche en Environnement Atmosphérique (CEREA), École des Ponts ParisTech (ENPC)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Institut National de l'Environnement Industriel et des Risques (INERIS), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Institute for Atmospheric and Earth System Research (INAR)
Subjects: Atmospheric Science, [SDU]Sciences of the Universe [physics], 114 Physical sciences
Abstract: With the growing evidence that high particle number concentrations may impact health, modelling their emissions and understanding formation processes is necessary, especially in cities where many people are exposed. As emission inventories of particle numbers and size distribution over cities are usually not available, a methodology is defined to estimate them from PM2.5 emissions and ratios of PM1 / PM2.5 and PM0.1 / PM2.5 by activity sector. In this methodology, a fitting parameter αem is used to redistribute the number concentrations in the lowest emission diameter range. This parameter is chosen by comparing measured and simulated number concentrations during non-nucleation days. The emission size distribution is then finely discretised by conserving both mass and number in each of the size ranges where emissions are specified. The methodology is applied over Greater Paris during the MEGAPOLI campaign (July 2009). Three-dimensional simulations are performed using the chemistry transport model Polair3D/Polyphemus coupled to the aerosol module SSH-aerosol to represent the evolution of particles by condensation, evaporation, coagulation, and nucleation, with a sectional approach for the size distribution. The model is first compared to measurements during non-nucleation days, and the influence over the month of July 2009 of three different nucleation parameterisations is assessed, i.e. binary (sulfuric acid, water), ternary (sulfuric acid, ammonia, water), and heteromolecular (extremely low-volatility organic compounds (ELVOCs) from monoterpenes and sulfuric acid). The modelled number concentrations compare very well to measurements, with an average normalised mean error of 42 % for the daily number concentrations of particles larger than 10 nm and 37 % for the number concentrations of particles larger than 100 nm. The influence of the binary nucleation is low, and the ternary nucleation scheme leads to better simulated number concentrations (in terms of bias and error) at only one site out of three, but it systematically reduces the model to measurement correlation, suggesting that ternary nucleation may not be the dominant process in new particle formation. However, the relative bias and error, as well as the correlation at suburban sites, are systematically improved using the heteromolecular nucleation scheme involving sulfuric acid and ELVOCs from monoterpenes. This suggests that heteromolecular nucleation may be important in cities, especially at suburban sites in summer, and that a better characterisation of the emissions of ELVOC precursors from traffic is needed.
Published: 2022

19. Proportional marginal effects for global sensitivity analysis

Author: Herin, Margot, Idrissi, Marouane Il, Chabridon, Vincent, Iooss, Bertrand, DECISION, LIP6, Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Performance, Risque Industriel, Surveillance pour la Maintenance et l’Exploitation (EDF R&D PRISME), EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Institut de Mathématiques de Toulouse UMR5219 (IMT), Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Saclay Industrial Lab for Artificial Intelligence Research (SINCLAIR AI Lab), THALES [France]-TOTAL FINA ELF-EDF (EDF), Méthodes d'Analyse Stochastique des Codes et Traitements Numériques (GdR MASCOT-NUM), and Centre National de la Recherche Scientifique (CNRS)
Subjects: Methodology (stat.ME), FOS: Computer and information sciences, Cooperative game theory, [MATH.MATH-ST]Mathematics [math]/Statistics [math.ST], Proportional values, FOS: Mathematics, Mathematics - Statistics Theory, Statistics Theory (math.ST), Shapley effects, Dependence, Sobol' indices, [STAT.ME]Statistics [stat]/Methodology [stat.ME], Statistics - Methodology
Abstract: Performing (variance-based) global sensitivity analysis (GSA) with dependent inputs has recently benefited from cooperative game theory concepts.By using this theory, despite the potential correlation between the inputs, meaningful sensitivity indices can be defined via allocation shares of the model output's variance to each input. The ``Shapley effects'', i.e., the Shapley values transposed to variance-based GSA problems, allowed for this suitable solution. However, these indices exhibit a particular behavior that can be undesirable: an exogenous input (i.e., which is not explicitly included in the structural equations of the model) can be associated with a strictly positive index when it is correlated to endogenous inputs. In the present work, the use of a different allocation, called the ``proportional values'' is investigated. A first contribution is to propose an extension of this allocation, suitable for variance-based GSA. Novel GSA indices are then proposed, called the ``proportional marginal effects'' (PME). The notion of exogeneity is formally defined in the context of variance-based GSA, and it is shown that the PME allow the distinction of exogenous variables, even when they are correlated to endogenous inputs. Moreover, their behavior is compared to the Shapley effects on analytical toy-cases and more realistic use-cases.
Published: 2023

20. Variance-based importance measures in the linear regression context: Review, new insights and applications

Author: Clouvel, Laura, Iooss, Bertrand, Chabridon, Vincent, Il Idrissi, Marouane, Robin, Frédérique, PERformance et prévention des Risques Industriels du parC par la simuLation et les EtudeS (EDF R&D PERICLES), EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Performance, Risque Industriel, Surveillance pour la Maintenance et l’Exploitation (EDF R&D PRISME), Méthodes d'Analyse Stochastique des Codes et Traitements Numériques (GdR MASCOT-NUM), Centre National de la Recherche Scientifique (CNRS), Institut de Mathématiques de Toulouse UMR5219 (IMT), Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [STAT]Statistics [stat], Linear model, Proportional values, Relative weight analysis, Variance decomposition, Shapley effects, Multicollinearity, Sensitivity analysis
Abstract: In the context of regression analysis, importance measures are effective tools to perform feature selection or to interpret a model by ranking the most influential regressors. In particular, variance-based importance measures (VIMs) are prominent in the field of statistics, but also in the most recent field of global sensitivity analysis, due to their accessible interpretation as variance shares of the explained variable. By focusing on the linear regression model, this work aims at revisiting the overview of the most well-founded methods (some of them being rather old and sometimes, misunderstood), while clarifying their respective positioning, conditions of use, intrinsic capabilities, and interpretation. Some challenges are discussed, such as the case of dependent inputs and the case of a high input dimension. A particular set of VIMs, called the Johnson indices, has shown the potential to solve both previously mentioned challenges. Their equivalence with other known VIMs, the Lindeman-Merenda-Gold (LMG) indices, is proved in the case of two inputs. The practical relevancy of such tools is highlighted through their empirical study on simulated data, as well as public datasets. An application to classification tasks (logistic regression) is also presented in the supplementary material.
Published: 2023

21. Advanced nanoscale characterizations of solid oxide cell electrodes

Author: Giuseppe Sassone, Ozden Celikbilek, Maxime Hubert, Katherine Develos Bagarinao, Thomas David, Laure Guetaz, Isabelle Martin, Julie Villanova, Lea Rorato, Bertrand Morel, Aline Léon, Jérôme Laurencin, ARC-Nucleart CEA Grenoble (NUCLEART), Laboratoire d'Innovation pour les Technologies des Energies Nouvelles et les nanomatériaux (LITEN), Institut National de L'Energie Solaire (INES), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de L'Energie Solaire (INES), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Département Technique Conversion et Hydrogène (DTCH), Intelligent Systems Institute [Tsukuba] (IS AIST), National Institute of Advanced Industrial Science and Technology (AIST), Département des Technologies des NanoMatériaux (DTNM), CAMECA SAS, European Synchroton Radiation Facility [Grenoble] (ESRF), European Institute For Energy Research (EIFER), Universität Karlsruhe (TH)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), ANR-22-PEHY-0008,CELCER-EHT,Ceramic Cells for durable performant and cost efficient HTE(2022), and European Project: 874577,NewSOC
Subjects: [PHYS]Physics [physics], General Medicine
Abstract: Solid oxide cells (SOCs) have attracted a growing attention thanks to their high efficiency and ability to operate in both electrolysis (SOEC) and fuel cell (SOFC) modes. Despite its great potential, the current SOC technology faces significant cell degradation during long-term operation. The degradation phenomena are still not well understood as they involve complex and intricate processes arising at different length scales. Additionally, it has been shown that the degradation rate under SOEC operation is generally higher than in SOFC mode. To address this issue, durability tests were performed in SOEC mode at 750, 800 and 850 °C for 2000 h at -1 A cm-2 in 10/90 vol.% H2/H2O and dry air. The electrochemical performance of the cells was assessed using electrochemical impedance spectroscopy. In addition, advanced characterization techniques with nanometer and atomic resolution have been used to study material degradation after long-term testing.
Published: 2023

22. Disodium naphthalene dicarboxylate based negative electrode engineering for organic-inorganic hybrid sodium batteries

Author: Roberto Russo, François Rabuel, Mathieu Morcrette, Carine Davoisne, Gregory Gachot, Arash Jamali, Gwenaelle Toussaint, Philippe Stevens, Matthieu Becuwe, Laboratoire des Matériels Électriques (EDF R&D LME), EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Laboratoire réactivité et chimie des solides - UMR CNRS 7314 (LRCS), Université de Picardie Jules Verne (UPJV)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Réseau sur le stockage électrochimique de l'énergie (RS2E), Aix Marseille Université (AMU)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Collège de France (CdF (institution))-Université de Picardie Jules Verne (UPJV)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Pau et des Pays de l'Adour (UPPA)-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA)-Nantes Université (Nantes Univ)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM), Université de Montpellier (UM), Advanced Lithium Energy Storage Systems - ALISTORE-ERI (ALISTORE-ERI), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Plateforme Analytique (PFA), Université de Picardie Jules Verne (UPJV), and EDF (EDF)
Subjects: Renewable Energy, Sustainability and the Environment, General Materials Science, [CHIM.MATE]Chemical Sciences/Material chemistry, Waste Management and Disposal, Industrial and Manufacturing Engineering
Abstract: International audience; This article presents the engineering of disodium naphthalene dicarboxylate (Na2-NDC) based negative organic electrodes for sodium-ion batteries. Firstly, different synthesis strategies were used to modify the morphology and crystal structure of the active material particles in order to improve their electrochemical performance. The engineering of the electrodes was then carried out to maximize the composite performances, which were initially evaluated in half-cells against Na. After electrode optimization, a complete cell was assembled by coupling the Na2-NDC negative electrode with Na3V2(PO4)2F3 (NVPF) as an inorganic-based cathode, to obtain a complete so-called “hybrid” cell. A thorough electrochemical study of the complete cell was carried out to evaluate the cell stability during cycling using different electrolyte additives. Thanks to the electrode and electrolyte optimizations, the NVPF/Na2-NDC hybrid cell demonstrated remarkable electrochemical performance, in terms of reversible capacity, cycling stability and rate performance. The full cells in the present work showed an energy density between 260 and 300 Wh/kg in the first cycle at low C-rate, and an energy density of 120–155 Wh/kg after 400 cycles, superior to those previously reported in the literature for the hybrid cell.In addition, a series of post-mortem analyses were carried out, based on GC/MS analysis, UV–Vis spectroscopy and electron microscopy (SEM/EDX), to understand the evolution of the performance over time and thus guide future research in this field to design the next generation of more durable and easily recycled sodium-ion battery.
Published: 2023

23. PEPR TASE: Technologies avancées des systèmes energétiques

Author: Guillemoles, Jean-François, Azais, Philipe, Retiere, Nicolas, Institut de Recherche et Développement sur l'Energie Photovoltaïque (IRDEP), Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Institut Photovoltaïque d’Ile-de-France (IPVF), 91120 Palaiseau, France (IPVF), École polytechnique (X)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire de Génie Electrique de Grenoble (G2ELab ), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), and Université Grenoble Alpes (UGA)
Subjects: [SPI]Engineering Sciences [physics], [SDE]Environmental Sciences, [CHIM]Chemical Sciences, [SHS]Humanities and Social Sciences
Abstract: International audience; Programme d'augmentation de la part des énergies renouvelables dans le mix réseau(Plan Pluriannuel de l'Energie : PPE)• Installations massives d'EnR : de 48,6 GWc fin 2017 à 100 -110 GWc en 2028• PV : 35 à 44 GWc, Eolien : ~ 33 - 35 GWc, dont 5 à 6 GWc en mer, hydro. ~26,5 GWp• connectés au réseau (36 % de l'électricité fournie par ENR).• Développer les infrastructures de recharge des véhicules électriques, l'écrêtement des pointes etl'autoconsommation, la flexibilité et la résilience des réseaux• En 2050: besoin en énergie finale ~1 060 TWh (1 628 TWh en 2018), dont ~580 TWh électriquesOpérer une transition responsable• Qui mette l’humain au centre , qui soit bien appropriée socialement;• Qui soit conforme au développement durable et minimise les impacts environnementaux;Plan de réindustrialisation et de souveraineté (France Relance)• Moderniser l’appareil productif et décarboner l'industrie ;• (Re)localiser les activités stratégiques critiques ;• Innover, en soutenant les investissements en R&D tout en développant les compétences.
Published: 2023

24. Modelling the atmospheric chlorine 36 dry deposition on grass usingmicrometeorology

Author: Sourabie, Déo-Gratias, Hebert, Didier, Lourino-Cabana, Beatriz, Benedetti, Lucilla, Vitorge, Elsa, Guillou, Valery, Maro, Denis, Laboratoire de Radioécologie de Cherbourg-Octeville (IRSN/PSE-ENV/SRTE/LRC), Service de recherche sur les transferts et les effets des radionucléides sur les écosystèmes (IRSN/PSE-ENV/SRTE), Institut de Radioprotection et de Sûreté Nucléaire (IRSN)-Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Laboratoire National d’Hydraulique et Environnement (EDF R&D LNHE), EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), EDF DIPDE, IRSN, EDF, and European Geosciences Union
Subjects: [SDU]Sciences of the Universe [physics], [SDE]Environmental Sciences, Dry deposits, chlorine 36, AMS, Micrometeorology, Modelling
Abstract: International audience; Chlorine 36 (36Cl, T1/2 = 301,000 years) is a radionuclide with natural and anthropogenic origin that can be rejected during decommissioning of nuclear power plants or chronically during recycling of used nuclear fuels. Once emitted into the atmosphere, chlorine 36 (gas and particles) can be transferred to the soil and vegetation cover by dry and wet deposition. However, quantitative constraints of these deposits are very scarce. Because of its relatively high mobility in the geosphere and its high bioavailability, chlorine 36 fate in the environment should be studied for environmental and human impact assessments. The aim of this study is therefore to develop dry depositional models for the gaseous and particulate fractions of chlorine 36. The model used for the parameterization of gaseous chlorine 36 dry deposition on grass is the << Big-leaf >> model based on the electrical analogy (Seinfield 1985). It was adapted from the Bah (2020) model developed for iodine. For particulate chlorine 36, the Damay Pellerin (2017) model was used. This model requiring the diameter of particulate chlorine 36 to be known, a sample of aerosol was taken in the chlorine 36 plume to determine on which particle size it is fixed. The sampling was performed on a low pressure impinger (LPI, DEKATI) of 13 levels for particles with diameters between 30nm and 10μm. In order to obtain model input data, meteorological and micrometeorological parameters were measured continuously at the IRSN La Hague technical platform (PTILH, France). The PTILH is located 2 km north of Orano La-Hague plant which emits small quantities of chlorine 36. An ultrasonic anemometer (Young 81000V) installed at a height of 4,5 m from the ground measured the direction (°), the velocity u (m/s) and the air friction velocity u* (m/s), the sensible heat flux H, the Monin-Obukhov length (L) and the atmospheric stability (1/L). A weather station (Spectrum Watchdog, series 2000) measured temperature Ts (°C), relative humidity RH (%), dew point (°C), global radiation SR (Wat/m^2) and photosynthetic active radiation PAR (μM/m^2.s). Sampling campaigns of 2 weeks were also conducted at the PTILH site to determine experimental depositional rates of chlorine 36. Chlorine 36 measurements were carried out by acceleration mass spectrometry at CEREGE-LN2C (France).The particle size distribution of the aerosol sample from chlorine 36 plume shows two peaks, a main one at 2μm and a second one at 10μm, typical distribution of marine aerosol. The modelsyield chlorine 36 depositional velocities between 6,7.10-3 and 10-2 m/s for the particulate fraction,and between 5.10-3 and 1,3.10-2 m/s for the gaseous one. The total dry depositional velocities(particles and gas) calculated from the model are less than one order of magnitude than the onesobtained experimentally.
Published: 2023

25. Decomposition of Convex High Dimensional Aggregative Stochastic Control Problems

Author: Adrien Seguret, Clemence Alasseur, J. Frédéric Bonnans, Antonio De Paola, Nadia Oudjane, Vincenzo Trovato, Optimisation, Simulation, Risque et Statistiques pour les Marchés de l’Energie (EDF R&D OSIRIS), EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), CEntre de REcherches en MAthématiques de la DEcision (CEREMADE), Université Paris Dauphine-PSL, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Finance des Marchés d'Energie (FiME Lab), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-CREST-EDF R&D (EDF R&D), Dynamical Interconnected Systems in COmplex Environments (DISCO), Inria Saclay - Ile de France, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire des signaux et systèmes (L2S), CentraleSupélec-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-CentraleSupélec-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Laboratoire des signaux et systèmes (L2S), CentraleSupélec-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Department of Electrical and Electronic Engineering [London] (DEEE), Imperial College London, Department of civil, environmental and mechanical engineering [Trento], University of Trento [Trento], and The first, second, third and fifth author thank the FiME Lab (Institut Europlace de Finance). The third author was supported bythe PGMO project 'Optimal control of conservation equations', itself supported by iCODE(IDEX Paris-Saclay) and the HadamardMathematics LabEx
Subjects: 93E20, 65K10, 90C25, 90C39, 90C15, Control and Optimization, Optimization and Control (math.OC), AMS subject classifications : 93E20,65K10, 90C25, 90C39, 90C15, Applied Mathematics, Stochastic optimization, [SPI.NRJ]Engineering Sciences [physics]/Electric power, Stochastic gradient, FOS: Mathematics, [MATH.MATH-OC]Mathematics [math]/Optimization and Control [math.OC], Mathematics - Optimization and Control, Uzawa's algorithm, Lagrangian decomposition
Abstract: We consider the framework of convex high dimensional stochastic control problems, in which the controls are aggregated in the cost function. As first contribution, we introduce a modified problem, whose optimal control is under some reasonable assumptions an $\varepsilon$-optimal solution of the original problem. As second contribution, we present a decentralized algorithm whose convergence to the solution of the modified problem is established. Finally, we study the application of the developed tools in an engineering context, studying a coordination problem for large populations of domestic thermostatically controlled loads (TCLs), 24 pages
Published: 2023

26. The Contextuality of Privacy Issues in Interactive Services, and its Consequences for Design

Author: Fréjus, Myriam, Guibourdenche, Julien, Martini, Dominique, EDF R&D SEQUOIA, EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), TECHnologies pour la Coopération, l’Interaction et les COnnaissances dans les collectifs (Tech-CICO), Institut Charles Delaunay (ICD), and Université de Technologie de Troyes (UTT)-Centre National de la Recherche Scientifique (CNRS)-Université de Technologie de Troyes (UTT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Consent, Design, Privacy, Situated analysis, [SCCO.PSYC]Cognitive science/Psychology, Context, [SHS.PSY]Humanities and Social Sciences/Psychology, [INFO.INFO-HC]Computer Science [cs]/Human-Computer Interaction [cs.HC], Lived experience, Privacité, Conception, Consentement, Analyse située, Expérience vécue, Contexte, Données personnelles
Abstract: International audience; We are interested in how issues relating to privacy and confidentiality are incorporated when using interactive services. Two smart home services based on the use of data from "smart" electricity meters have been evaluated to establish the guarantees and forms of interaction necessary for their appropriation. We show that, given the contextual, dynamic and social nature of privacy, normative responses such as those promoted by the regulator (predefinition of sensitive data, prior to use consent, privacy as the default setting) are insufficient. As mentioned in previous works, the design choices must promote as components of the systems the user control of data throughout the interaction, as well as transparency of the data, processing and actors. However, our results highlight an important dimension not previously addressed: the need to adopt a temporal and diachronic vision of privacy and to broaden the question of interaction beyond use by considering the life cycle of the service and of the relationship with its suppliers.; Nous nous intéressons à la façon dont les questions de vie privée et de sa préservation s'instancient dans l'utilisation de services interactifs. Deux services relatifs à l'habitat et basés sur l'exploitation de données issues de compteurs électriques « intelligents » ont été évalués pour établir les garanties et formes d'interactions nécessaires à leur appropriation. Nous montrons que, compte tenu de la nature contextuelle, dynamique et sociale de la privacy, les réponses normatives telles que celles promues par le législateur (prédéfinition des données sensibles, consentement a priori, privacy intégrée seulement au stade de la conception du système) sont insuffisantes. Comme cela a pu être évoqué dans des travaux antérieurs, les choix de conception doivent favoriser la maîtrise des données dans l'interaction en proposant des moyens d'actions et une transparence des données, traitements et acteurs, en tant que composantes des systèmes. Toutefois, nos résultats mettent en exergue une dimension importante non traitée jusqu'alors : la nécessité d'adopter une vision temporelle et diachronique de la privacy, pour élargir la question de l'interaction au-delà de l'utilisation en considérant la durée de vie du service et de la relation avec ses fournisseurs.
Published: 2023

27. PANAME – Project synergy of atmospheric research in the Paris region

Author: Haeffelin, Martial, Kotthaus, Simone, Bastin, Sophie, Bouffies-Cloché, Sophie, Cantrell, Chris, Christen, Andreas, Dupont, Jean-Charles, Foret, Gilles, Gros, Valérie, Lemonsu, Aude, Leymarie, Juliette, Lohou, Fabienne, Madelin, Malika, Masson, Valéry, Michoud, Vincent, Price, Jeremy, Ramonet, Michel, Ribaud, Jean-Francois, Sartelet, Karine, Wurtz, Jean, Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), SPACE - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Albert-Ludwigs-Universität Freiburg, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12), Laboratoire d'aérologie (LAERO), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Pôle de recherche pour l'organisation et la diffusion de l'information géographique (PRODIG (UMR_8586 / UMR_D_215 / UM_115)), Université Paris 1 Panthéon-Sorbonne (UP1)-Institut de Recherche pour le Développement (IRD)-AgroParisTech-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), United Kingdom Met Office [Exeter], Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Centre d'Enseignement et de Recherche en Environnement Atmosphérique (CEREA), École des Ponts ParisTech (ENPC)-EDF R&D (EDF R&D), and EDF (EDF)-EDF (EDF)
Subjects: [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph]
Abstract: International audience; The Paris region (France) is increasingly the focus of urban atmospheric research. Numerous national and international research projects have chosen Europe’s largest metropolitan region as their study area to better understand and predict critical hazards (incl. heat, air pollution, thunderstorms) in the context of a changing climate. Located on rather flat terrain in continental, mid-latitude climates, the densely populated Paris region is very suitable for the evaluation of urban processes in numerical simulations at different scales. The European research infrastructures ACTRIS and ICOS are developing strategies for the improved operational monitoring of air pollution and greenhouse gas budgets, respectively. Various research projects are conducting fundamental process studies and model developments to investigate the dynamics and chemistry of the urban atmosphere and its interactions with the rural surroundings and regional-scale flow to better quantify associated health risks and inform sustainable planning.In addition to numerous modelling activities (chemistry-transport, numerical weather prediction, climate projections), diverse atmospheric observations are collected. These include dense surface station networks, turbulent flux towers, and ground-based atmospheric remote sensing to monitor the atmospheric boundary layer. This multi-project context motivates the pooling of resources.To facilitate efficient project synergy and to optimise the coordination of the individual experimental campaigns, the PANAME initiative (https://paname.aeris-data.fr/) was established. PANAME provides a framework to optimise the design of the Paris region measurement network and helps to standardise the operations. A professional, multi-disciplinary data portal is developed at the French AERIS atmospheric data centre to host the PANAME observations and model results. Here, data are collected and formatted, standardised advanced products are derived from the diverse sensor networks and high-quality visualisations are generated in near real-time. The presentation will provide an overview on the scientific objectives of the on-going projects, the deployment of measurements and simulation tools, and the data portal design.
Published: 2023

28. A Quantization Procedure for Nonlinear Pricing with an Application to Electricity Markets

Author: Jacquet, Quentin, van Ackooij, Wim, Alasseur, Clémence, Gaubert, Stéphane, Optimisation, Simulation, Risque et Statistiques pour les Marchés de l’Energie (EDF R&D OSIRIS), EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), TROPICAL (TROPICAL), Centre de Mathématiques Appliquées - Ecole Polytechnique (CMAP), École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS)-Inria Saclay - Ile de France, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Laboratoire de Finance des Marchés d'Energie (FiME Lab), Université Paris Dauphine-PSL, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-CREST-EDF R&D (EDF R&D), and École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Optimization and Control (math.OC), FOS: Mathematics, [MATH.MATH-OC]Mathematics [math]/Optimization and Control [math.OC], Mathematics - Optimization and Control
Abstract: We consider a revenue maximization model, in which a company aims at designing a menu of contracts, given a population of customers. A standard approach consists in constructing an incentive-compatible continuum of contracts, i.e., a menu composed of an infinite number of contracts, where each contract is especially adapted to an infinitesimal customer, taking his type into account. Nonetheless, in many applications, the company is constrained to offering a limited number of contracts. We show that this question reduces to an optimal quantization problem, similar to the pruning problem that appeared in the max-plus based numerical methods in optimal control. We develop a new quantization algorithm, which, given an initial menu of contracts, iteratively prunes the less important contracts, to construct an implementable menu of the desired cardinality, while minimizing the revenue loss. We apply this algorithm to solve a pricing problem with price-elastic demand, originating from the electricity retail market. Numerical results show an improved performance by comparison with earlier pruning algorithms.
Published: 2023

29. A comparison between Bayesian and ordinary kriging based on validation criteria: application to radiological characterisation

Author: Wieskotten, Martin, Crozet, Marielle, Iooss, Bertrand, Lacaux, Céline, Marrel, Amandine, EA2151 Laboratoire de Mathématiques d'Avignon (LMA), Avignon Université (AU), Institut des Sciences et technologies pour une Economie Circulaire des énergies bas carbone (ISEC), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Commission des méthodes d'analyse du CEA (CETAMA), Département de recherche sur les procédés pour la mine et le recyclage du combustible (DMRC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Performance, Risque Industriel, Surveillance pour la Maintenance et l’Exploitation (EDF R&D PRISME), EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Méthodes d'Analyse Stochastique des Codes et Traitements Numériques (GdR MASCOT-NUM), Centre National de la Recherche Scientifique (CNRS), Institut de Mathématiques de Toulouse UMR5219 (IMT), Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Institut de recherche sur les systèmes nucléaires pour la production d'énergie bas carbone (IRESNE), and Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3)
Subjects: Methodology (stat.ME), FOS: Computer and information sciences, model validation, [MATH.MATH-ST]Mathematics [math]/Statistics [math.ST], FOS: Mathematics, Mathematics - Statistics Theory, kriging, geostatistics, Statistics Theory (math.ST), uncertainty, Statistics - Methodology
Abstract: In decommissioning projects of nuclear facilities, the radiological characterisation step aims to estimate the quantity and spatial distribution of different radionuclides. To carry out the estimation, measurements are performed on site to obtain preliminary information. The usual industrial practice consists in applying spatial interpolation tools (as the ordinary kriging method) on these data to predict the value of interest for the contamination (radionuclide concentration, radioactivity, etc.) at unobserved positions. This paper questions the ordinary kriging tool on the well-known problem of the overoptimistic prediction variances due to not taking into account uncertainties on the estimation of the kriging parameters (variance and range). To overcome this issue, the practical use of the Bayesian kriging method, where the model parameters are considered as random variables, is deepened. The usefulness of Bayesian kriging, whilst comparing its performance to that of ordinary kriging, is demonstrated in the small data context (which is often the case in decommissioning projects). This result is obtained via several numerical tests on different toy models, and using complementary validation criteria: the predictivity coefficient (Q${}^2$), the Predictive Variance Adequacy (PVA), the $\alpha$-Confidence Interval plot (and its associated Mean Squared Error alpha (MSEalpha)), and the Predictive Interval Adequacy (PIA). The latter is a new criterion adapted to the Bayesian kriging results. Finally, the same comparison is performed on a real dataset coming from the decommissioning project of the CEA Marcoule G3 reactor. It illustrates the practical interest of Bayesian kriging in industrial radiological characterisation.
Published: 2023

30. Equilibration process of out-of-equilibrium sea-states induced by strong depth variation: Evolution of coastal wave spectrum and representative parameters

Author: Yuxiang Ma, Jie Zhang, Michel Benoit, Dalian University of Technology, Laboratoire National d’Hydraulique et Environnement (EDF R&D LNHE), EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (LHSV), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), Institut de Recherche sur les Phénomènes Hors Equilibre (IRPHE), and Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Environmental Engineering, Ocean Engineering, [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph], ComputingMilieux_MISCELLANEOUS
Abstract: International audience; Recent studies showed both experimental and numerical evidence that the occurrence probability of freak waves could be significantly enhanced as results of non-equilibrium dynamics induced by strong depth variations. The sea-state is characterized by strong non-Gaussian behavior in a short spatial extent after the depth transition, covering a few wavelengths. In this work, we investigate the complete equilibration process of an out-of-equilibrium sea-state via high-fidelity numerical simulations. In the simulations, the region after the depth transition is set as long as around one hundred wavelengths, such that the spectral adaptation develops and terminates eventually. The results are analyzed with spectral, cross-spectral and statistical approaches. It is shown that there are two stages with different spatial scales in the equilibration process. In the short scale, the sea-state is characterized by significant changes in wave statistics, freak wave occurrence probability is intensified. In the long scale, the wave spectrum undergoes strong modulation, the spectral peak disintegrate into a relative broad band, and low-frequency waves are enhanced as well. We show evidence that the spectral changes in the long scale are due to interactions of free components. The wave nonlinearity is shown to be positively correlated to the magnitude of the dynamical responses, but irrelevant to the length of the spatial scales in the equilibration process. In the established shallow-water equilibrium, the freak wave occurrence probability becomes less than Gaussian expectation and the waves are asymmetric in the vertical direction and symmetric in the horizontal.
Published: 2023

31. Electrochemical Behavior of Morphology-Controlled Copper (II) Hydroxide Nitrate Nanostructures

Author: Julien Sarmet, Christine Taviot-Gueho, Rodolphe Thirouard, Fabrice Leroux, Camille Douard, Insaf Gaalich, Thierry Brousse, Gwenaëlle Toussaint, Philippe Stevens, Institut de Chimie de Clermont-Ferrand (ICCF), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Institut national polytechnique Clermont Auvergne (INP Clermont Auvergne), Université Clermont Auvergne (UCA)-Université Clermont Auvergne (UCA), Institut des Matériaux Jean Rouxel (IMN), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Nantes université - UFR des Sciences et des Techniques (Nantes univ - UFR ST), Nantes Université - pôle Sciences et technologie, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ)-Nantes Université - pôle Sciences et technologie, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ)-Nantes Université - Ecole Polytechnique de l'Université de Nantes (Nantes Univ - EPUN), Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ), Réseau sur le stockage électrochimique de l'énergie (RS2E), Aix Marseille Université (AMU)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Collège de France (CdF (institution))-Université de Picardie Jules Verne (UPJV)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Pau et des Pays de l'Adour (UPPA)-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA)-Nantes Université (Nantes Univ)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM), Université de Montpellier (UM), Laboratoire des Matériels Électriques (EDF R&D LME), EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), ANR-20-CE05-0024,LaDHy,hydroxydes lamellaires pour systèmes de stockage innovants(2020), and ANR-10-LABX-0076,STORE-EX,Laboratory of excellency for electrochemical energy storage(2010)
Subjects: [CHIM.CRIS]Chemical Sciences/Cristallography, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], [CHIM]Chemical Sciences, General Materials Science, General Chemistry, Condensed Matter Physics
Abstract: International audience; Nanostructure control is an important issue when using electroactive materials in energy conversion and storage devices. In this study, we report various methods of synthesis of nanostructured copper (II) hydroxide nitrate (Cu-2(OH)(3)NO3) with a layered hydroxide salt (LHS) structure using various synthesis methods and investigate the correlation between nanostructure, morphology, and their pseudocapacitive electrochemical behavior. The variations in nanostructure size and morphology were comprehensively explored by combining X-ray diffraction (XRD) and scanning electron microscopy (SEM), while the electrochemical activity was characterized using cyclic voltammetry. We demonstrate that Cu-2(OH)(3)NO3-LHS nanostructured submicron particles produced by alkaline precipitation with 88% of the copper cations can cycle with a two-electron redox process. Unfortunately, the electroactivity decreases rapidly from the first cycle due to the occurrence of structural transformations and subsequent electrochemical grinding. However, samples obtained by ultrasonication and microwave synthesis, two original synthesis methods for LHS materials, formed of nanosized crystalline domains agglomerated in micron-sized particles, represent a good compromise between capacity and cyclability. Moreover, by using pair distribution function analysis on electrode materials after repeated cycling, we were able to follow the chemical and structural changes occurring in Cu-2(OH)(3)NO3 materials during electrochemical cycling with first a quick transformation to Cu2O and then the appearance of Cu metal and copper acetate Cu(II)(2)(O2CCH3)(4)center dot 2H(2)O.
Published: 2023

32. A ROS-based kinematic calibration tool for serial robots: the unburdeing of a crucial task

Author: Pascal, Caroline, Doaré, Olivier, Chapoutot, Alexandre, Unité d'Informatique et d'Ingénierie des Systèmes (U2IS), École Nationale Supérieure de Techniques Avancées (ENSTA Paris), Institut des Sciences de la mécanique et Applications industrielles (IMSIA - UMR 9219), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École Nationale Supérieure de Techniques Avancées (ENSTA Paris)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), and Carnot TSN, Carnot Mines, CIEDS project APRO
Subjects: [SPI.AUTO]Engineering Sciences [physics]/Automatic
Abstract: The use of serial robots for industrial and research purposes is often limited by a flawed positioning accuracy, caused by the differences between the robot nominal model, and the real one. Such an issue can be solved by means of kinematic calibration, which are usually tedious and intricate tasks. In this paper, we propose a complete kinematic calibration procedure relying on established geometric modeling, measurements design and parameters identification methods, as well as multiple integration tools, to provide a high adaptability as well as a simplified handling. The overall process was bundled up in a ROS-based modular and user-friendly kinematic calibration package for serial robots, whose main objective is to offer a smooth and fully integrated framework. Our solution was successfully tested using a motion tracking device, and allowed to increase the overall positioning accuracy of two different serial robots by 75% in a matter of hours.
Published: 2023

33. Combining Dantzig-Wolfe and Benders decompositions to solve a large-scale nuclear outage planning problem

Author: Halil Şen, Rodolphe Griset, François Vanderbeck, Boris Detienne, Marc Porcheron, Pascale Bendotti, Optimisation, Simulation, Risque et Statistiques pour les Marchés de l’Energie (EDF R&D OSIRIS), EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Reformulations based algorithms for Combinatorial Optimization (Realopt), Laboratoire Bordelais de Recherche en Informatique (LaBRI), Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure d'Électronique, Informatique et Radiocommunications de Bordeaux (ENSEIRB)-Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure d'Électronique, Informatique et Radiocommunications de Bordeaux (ENSEIRB)-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), RealOpt, Université de Bordeaux (UB)-École Nationale Supérieure d'Électronique, Informatique et Radiocommunications de Bordeaux (ENSEIRB)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-École Nationale Supérieure d'Électronique, Informatique et Radiocommunications de Bordeaux (ENSEIRB)-Centre National de la Recherche Scientifique (CNRS)-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), Formulations étendues et méthodes de décomposition pour des problèmes génériques d'optimisation (EDGE), and Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest
Subjects: Mathematical optimization, Information Systems and Management, General Computer Science, Computer science, Benders decomposition, 020209 energy, 0211 other engineering and technologies, ComputerApplications_COMPUTERSINOTHERSYSTEMS, 02 engineering and technology, Management Science and Operations Research, Benders' decomposition, Electricity demand, 7. Clean energy, Industrial and Manufacturing Engineering, Dantzig-Wolfe decomposition, 0202 electrical engineering, electronic engineering, information engineering, Decomposition (computer science), Production (economics), 021103 operations research, business.industry, Scale (chemistry), Nuclear outage scheduling, Integer programming, OR in energy, Modeling and Simulation, [MATH.MATH-OC]Mathematics [math]/Optimization and Control [math.OC], Electricity, business
Abstract: International audience; Optimizing nuclear unit outages is of significant economic importance for the French electricity company EDF, as these outages induce a substitute production by other more expensive means to fulfill electricity demand. This problem is quite challenging given the specific operating constraints of nuclear units, the stochasticity of both the demand and non-nuclear units availability, and the scale of the instances. To tackle these difficulties we use a combined decomposition approach. The operating constraints of the nuclear units are built into a Dantzig-Wolfe pricing subproblem whose solutions define the columns of a demand covering formulation. The scenarios of demand and non-nuclear units availability are handled in a Benders decomposition. Our approach is shown to scale up to the real-life instances of the French nuclear fleet.
Published: 2022

34. Numerical Resolution of McKean-Vlasov FBSDEs Using Neural Networks

Author: Maximilien Germain, Joseph Mikael, Xavier Warin, Laboratoire de Probabilités, Statistiques et Modélisations (LPSM (UMR_8001)), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), EDF (EDF), EDF R&D (EDF R&D), Optimisation, Simulation, Risque et Statistiques pour les Marchés de l’Energie (EDF R&D OSIRIS), EDF (EDF)-EDF (EDF), Laboratoire de Finance des Marchés d'Energie (FiME Lab), EDF (EDF)-EDF (EDF)-CREST-Université Paris Dauphine-PSL, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)
Subjects: Statistics and Probability, 65C30, 68T07, 49N80, 35Q89, General Mathematics, McKean-Vlasov FBSDEs, mean-field games, Deep BSDE, [MATH.MATH-PR]Mathematics [math]/Probability [math.PR], machine learning, Optimization and Control (math.OC), FOS: Mathematics, MSC 65C30, 68T07, 49N80, 35Q89, [MATH.MATH-OC]Mathematics [math]/Optimization and Control [math.OC], [MATH]Mathematics [math], Mathematics - Optimization and Control, Neural networks
Abstract: We propose several algorithms to solve McKean-Vlasov Forward Backward Stochastic Differential Equations. Our schemes rely on the approximating power of neural networks to estimate the solution or its gradient through minimization problems. As a consequence, we obtain methods able to tackle both mean field games and mean field control problems in moderate dimension. We analyze the numerical behavior of our algorithms on several examples including non linear quadratic models., 29 pages, revised version, to appear in Methodology and Computing in Applied Probability
Published: 2022

35. Graded damage in quasi‐brittle solids

Author: Nunziante Valoroso, Claude Stolz, Institut des Sciences de la mécanique et Applications industrielles (IMSIA - UMR 9219), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École Nationale Supérieure de Techniques Avancées (ENSTA Paris)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Dipartimento di Ingegneria [Napoli], Università degli Studi di Napoli 'Parthenope' = University of Naples (PARTHENOPE), Institut de Recherche en Génie Civil et Mécanique (GeM), Centre National de la Recherche Scientifique (CNRS)-École Centrale de Nantes (Nantes Univ - ECN), Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ)-Nantes université - UFR des Sciences et des Techniques (Nantes univ - UFR ST), Nantes Université - pôle Sciences et technologie, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ)-Nantes Université - pôle Sciences et technologie, Nantes Université (Nantes Univ)-Nantes Université - Institut Universitaire de Technologie Saint-Nazaire (Nantes Univ - IUT Saint-Nazaire), Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ)-Nantes Université - Ecole Polytechnique de l'Université de Nantes (Nantes Univ - EPUN), and Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ)
Subjects: damage mechanics, fracture, generalized standard materials, gradient, Lagrange multipliers, regularization, thick level sets, Numerical Analysis, Applied Mathematics, General Engineering, [SPI.MECA]Engineering Sciences [physics]/Mechanics [physics.med-ph]
Abstract: International audience; A novel approach to damage modeling for quasi-brittle solids is presented relying upon a differential inclusion that is closely related to the one of implicit gradient models. The proposed formulation naturally fits in the socalled non-local standard approach, whereby the framework of GeneralizedStandard Materials is extended to include gradients of internal variables to account for the physics of the fracture phenomenon in a regularized sense, i.e. via extended constitutive equations in which a length scale parameter brings to the macro level information about material microstructure. This concept is fully embodied into the present approach to quasi-brittle fracture, whereby progressive damage occurs in layers of finite thickness where the gradient of damage is bounded and a fully damaged region is understood as a fracture with no ambiguity. Key to the effective implementation of the model are the choice of two constitutive functions and the implicit tracking of regions in a state of progressive damage via Lagrange multipliers acting on internal constraints. The ideas are developed for a general Cauchy continuum and representative numerical simulations are included that demonstrate the model capabilities.
Published: 2022

36. Modelling extinction/re-ignition processes in fire plumes under oxygen-diluted conditions using flamelet tabulation approaches

Author: Ma, Li, Nmira, Fatiha, Consalvi, Jean-Louis, Mécanique des Fluides, Energies et Environnement (EDF R&D MFEE), EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Institut universitaire des systèmes thermiques industriels (IUSTI), and Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [SPI]Engineering Sciences [physics], flamelet progress variable model, Fuel Technology, Modeling and Simulation, General Chemical Engineering, Large eddy simulation, reduced-oxygen environments, steady laminar flamelet model, General Physics and Astronomy, Energy Engineering and Power Technology, General Chemistry, Fire plumes
Abstract: International audience; The main objective of this article is to investigate the capability of the flamelet progress variable (FPV) model to capture the extinction processes observed in under-ventilated fire scenarios. To this end, large eddy simulation (LES) of the methane line fire plumes in oxygen-reduced environments down to global extinction, investigated experimentally at the University of Maryland (UMD), is performed. Two experimental burner configurations, that differ by the presence (anchored) or not (non-anchored) of an oxygen anchor to stabilise the flame base, are considered leading to two different extinction modes. Both the FPV and the steady laminar flamelet (SLF) model coupled with a presumed filtered density function (FDF) are considered. The Rank Correlated Full Spectrum k-distribution (RCFSK) model is used as a gas radiative property model. In both non-anchored and anchored scenarios, the FPV model reproduces with fidelity the evolution of the fire plume structure, radiative loss, and combustion efficiency with decreasing XO2 down to global extinction, without introducing any adjustable constant. The extinction in the non-anchored scenario occurs owing to flame-based detachment coupled to the generation of a buoyancy-driven vortex and is found to be very sensitive to the grid resolution in the near burner region. The present results suggest that these processes can be adequately resolved with a spatial resolution of 2.5 mm in this region. The SLF model, for its part, provides reliable predictions comparable to the FPV as long as no local extinction/re-ignition process occurs.
Published: 2022

37. A decomposition method by interaction prediction for the optimization of maintenance scheduling

Author: Chancelier, Jean-Philippe, Bittar, Thomas, Carpentier, Pierre, Chancelier, J-Ph, Lonchampt, J��r��me, Centre d'Enseignement et de Recherche en Mathématiques et Calcul Scientifique (CERMICS), École des Ponts ParisTech (ENPC), Performance, Risque Industriel, Surveillance pour la Maintenance et l’Exploitation (EDF R&D PRISME), EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Optimisation et commande (OC), Unité de Mathématiques Appliquées (UMA), École Nationale Supérieure de Techniques Avancées (ENSTA Paris)-École Nationale Supérieure de Techniques Avancées (ENSTA Paris), and École Nationale Supérieure de Techniques Avancées (ENSTA Paris)
Subjects: Optimization and Control (math.OC), FOS: Mathematics, General Decision Sciences, [MATH.MATH-OC]Mathematics [math]/Optimization and Control [math.OC], Management Science and Operations Research, Mathematics - Optimization and Control
Abstract: Optimizing maintenance scheduling is a major issue to improve the performance of hydropower plants. We study a system of several physical components of the same family: either a set of turbines, a set of transformers or a set of generators. The components share a common stock of spare parts and experience random failures that occur according to known failure distributions. We seek a deterministic preventive maintenance strategy that minimizes an expected cost depending on maintenance and forced outages of the system. The Auxiliary Problem Principle is used to decompose the original large-scale optimization problem into a sequence of independent subproblems of smaller dimension while ensuring their coordination. Each subproblem consists in optimizing the maintenance on a single component. Decomposition-coordination techniques are based on variational techniques but the maintenance optimization problem is a mixed-integer problem. Therefore, we relax the dynamics and the cost functions of the system. The resulting algorithm iteratively solves the subproblems on the relaxed system with a blackbox method and coordinates the components. Relaxation parameters have an important influence on the optimization and must be appropriately chosen. An admissible maintenance strategy is then derived from the resolution of the relaxed problem. We apply the decomposition algorithm on a system with 80 components. It outperforms the reference blackbox method applied directly on the original problem.
Published: 2022

38. Online hierarchical forecasting for power consumption data

Author: Malo Huard, Margaux Brégère, Statistique mathématique et apprentissage (CELESTE), Inria Saclay - Ile de France, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire de Mathématiques d'Orsay (LMO), Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Optimisation, Simulation, Risque et Statistiques pour les Marchés de l’Energie (EDF R&D OSIRIS), EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Statistical Machine Learning and Parsimony (SIERRA), Département d'informatique - ENS Paris (DI-ENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Inria de Paris, Institut National de Recherche en Informatique et en Automatique (Inria), Laboratoire de Mathématiques d'Orsay (LMO), and Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
Subjects: FOS: Computer and information sciences, Consumption (economics), Computer Science - Machine Learning, Mathematical optimization, Demand Forecasting, Mean squared error, Series (mathematics), Computer science, Generalized additive model, Machine Learning (stat.ML), Machine Learning (cs.LG), Time Series Clustering, Online Learning, Forecasts Reconciliation, Electricity, [STAT.ML]Statistics [stat]/Machine Learning [stat.ML], Online Aggregation, [MATH.MATH-ST]Mathematics [math]/Statistics [math.ST], Statistics - Machine Learning, Benchmark (computing), Business and International Management, Linear combination, Projection (set theory), Hierarchical time series, Subspace topology
Abstract: We study the forecasting of the power consumptions of a population of households and of subpopulations thereof. These subpopulations are built according to location, to exogenous information and/or to profiles we determined from historical households consumption time series. Thus, we aim to forecast the electricity consumption time series at several levels of households aggregation. These time series are linked through some summation constraints which induce a hierarchy. Our approach consists in three steps: feature generation, aggregation and projection. Firstly (feature generation step), we build, for each considering group for households, a benchmark forecast (called features), using random forests or generalized additive models. Secondly (aggregation step), aggregation algorithms, run in parallel, aggregate these forecasts and provide new predictions. Finally (projection step), we use the summation constraints induced by the time series underlying hierarchy to re-conciliate the forecasts by projecting them in a well-chosen linear subspace. We provide some theoretical guaranties on the average prediction error of this methodology, through the minimization of a quantity called regret. We also test our approach on households power consumption data collected in Great Britain by multiple energy providers in the Energy Demand Research Project context. We build and compare various population segmentations for the evaluation of our approach performance.
Published: 2022

39. An algorithmic framework for the optimization of deep neural networks architectures and hyperparameters

Author: Keisler, Julie, Talbi, El-Ghazali, Claudel, Sandra, Cabriel, Gilles, Optimisation, Simulation, Risque et Statistiques pour les Marchés de l’Energie (EDF R&D OSIRIS), EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), EDF (EDF), Centre de Recherche en Informatique, Signal et Automatique de Lille - UMR 9189 (CRIStAL), and Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS)
Subjects: FOS: Computer and information sciences, Computer Science - Machine Learning, Time Series Forecasting, Computer Science - Artificial Intelligence, Evolutionary Algorithm, Neural Architecture Search, Computer Science - Neural and Evolutionary Computing, Metaheuristics, [INFO.INFO-NE]Computer Science [cs]/Neural and Evolutionary Computing [cs.NE], Directed Acyclic Graphs, Machine Learning (cs.LG), [INFO.INFO-AI]Computer Science [cs]/Artificial Intelligence [cs.AI], Artificial Intelligence (cs.AI), [INFO.INFO-LG]Computer Science [cs]/Machine Learning [cs.LG], Neural and Evolutionary Computing (cs.NE), Hyperparameter optimization, AutoML
Abstract: In this paper, we propose an algorithmic framework to automatically generate efficient deep neural networks and optimize their associated hyperparameters. The framework is based on evolving directed acyclic graphs (DAGs), defining a more flexible search space than the existing ones in the literature. It allows mixtures of different classical operations: convolutions, recurrences and dense layers, but also more newfangled operations such as self-attention. Based on this search space we propose neighbourhood and evolution search operators to optimize both the architecture and hyper-parameters of our networks. These search operators can be used with any metaheuristic capable of handling mixed search spaces. We tested our algorithmic framework with an evolutionary algorithm on a time series prediction benchmark. The results demonstrate that our framework was able to find models outperforming the established baseline on numerous datasets.
Published: 2023

40. Size effects in the toughening of brittle materials by heterogeneities: a non-linear analysis of front deformations

Author: Lebihain, Mathias, Vasoya, Manish, Lazarus, Véronique, Laboratoire Navier (NAVIER UMR 8205), École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Université Gustave Eiffel, Texas A&M University [College Station], Institut des Sciences de la mécanique et Applications industrielles (IMSIA - UMR 9219), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École Nationale Supérieure de Techniques Avancées (ENSTA Paris)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-EDF R&D (EDF R&D), and EDF (EDF)-EDF (EDF)
Subjects: Condensed Matter - Materials Science, Brittle failure, three-dimensional fracture, effective toughness, [SPI.MECA.MEMA]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Mechanics of materials [physics.class-ph], Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, coplanar perturbation, stress intensity factor, circular crack
Abstract: International audience; Traditional computational approaches in simulating crack propagation in perfectly brittle materials rely on the estimate of stress intensity factors along the rupture front. This proves highly challenging in 3D when the crack geometry departs from very specific cases for which analytical solutions are available, like e.g. the penny-shaped crack geometry. Here, we extend the first-order theory of Gao and Rice (1987), and predict the distribution of the mode I stress intensity factor KI along the front of a tensile coplanar crack that is slightly perturbed from a reference penny-shaped configuration, up to second order in the perturbation amplitude. Our theory is validated against analytical solutions available for embedded elliptical cracks, and its range of validity is further assessed using numerical simulations performed on cosine front perturbations of varying mode and amplitude. It is then used to develop a homogenization framework for the toughness of weakly disordered media. The effective toughness and its fluctuations are bridged quantitatively to the intensity of the toughness fluctuations and their spatial structure. Our theoretical predictions are compared to the results of ~1 million simulations of crack propagation building on our second-order theory and Fast Fourier Transforms. We show that the impact of toughness heterogeneities is size-dependent, as they generally weaken the material when the crack size is lower or comparable to the typical heterogeneity size, but reinforces it otherwise. It results in an apparent R-curve behavior of the brittle composite at the macroscale.
Published: 2023

41. X-ray microtomography investigation of damage fields ahead of cracks in CT and SENT C-Mn steel samples

Author: Richi Kumar, Jacques Besson, Andrew King, Anna Dahl, Thilo F. Morgeneyer, Centre des Matériaux (CDM), Mines Paris - PSL (École nationale supérieure des mines de Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Matériaux et Mécanique des Composants (EDF R&D MMC), EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Soleil proposal 20181343, and European Project: 755269,H2020-Euratom-1.2. - Contribute to the development of solutions for the management of ultimate nuclear waste ,NFRP-2016-2017-1,GEMMA(2017)
Subjects: [SPI]Engineering Sciences [physics], Mechanics of Materials, Modeling and Simulation, Computational Mechanics
Abstract: International audience
Published: 2023

42. Interleaved Electroactive Molecules into LDH Working on Both Electrodes of an Aqueous Battery-Type Device

Author: Julien Sarmet, Fabrice Leroux, Christine Taviot-Gueho, Patrick Gerlach, Camille Douard, Thierry Brousse, Gwenaëlle Toussaint, Philippe Stevens, Institut de Chimie de Clermont-Ferrand (ICCF), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Institut national polytechnique Clermont Auvergne (INP Clermont Auvergne), Université Clermont Auvergne (UCA)-Université Clermont Auvergne (UCA), Institut des Matériaux Jean Rouxel (IMN), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Nantes université - UFR des Sciences et des Techniques (Nantes univ - UFR ST), Nantes Université - pôle Sciences et technologie, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ)-Nantes Université - pôle Sciences et technologie, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ)-Nantes Université - Ecole Polytechnique de l'Université de Nantes (Nantes Univ - EPUN), Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ), Réseau sur le stockage électrochimique de l'énergie (RS2E), Aix Marseille Université (AMU)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Collège de France (CdF (institution))-Université de Picardie Jules Verne (UPJV)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Pau et des Pays de l'Adour (UPPA)-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA)-Nantes Université (Nantes Univ)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM), Université de Montpellier (UM), Laboratoire des Matériels Électriques (EDF R&D LME), EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), EDF (EDF), and ANR-20-CE05-0024,LaDHy,hydroxydes lamellaires pour systèmes de stockage innovants(2020)
Subjects: layered double hydroxide, Organic Chemistry, Pharmaceutical Science, [SDV.BBM.BM]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Molecular biology, Analytical Chemistry, LDH-ferrocene battery-type device, Chemistry (miscellaneous), Drug Discovery, LDH-riboflavin, Molecular Medicine, [CHIM]Chemical Sciences, Physical and Theoretical Chemistry, riboflavin, layered double hydroxide riboflavin LDH-riboflavin LDH-ferrocene battery-type device, [SDV.BBM.BC]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biochemistry [q-bio.BM]
Abstract: International audience; By selecting two electroactive species immobilized in a layered double hydroxide backbone (LDH) host, one able to act as a positive electrode material and the other as a negative one, it was possible to match their capacity to design an innovative energy storage device. Each electrode material is based on electroactive species, riboflavin phosphate (RF) on one side and ferrocene carboxylate (FCm) on the other, both interleaved into a layered double hydroxide (LDH) host structure to avoid any possible molecule migration and instability. The intercalation of the electroactive guest molecules is demonstrated by X-ray diffraction with the observation of an interlayer LDH spacing of about 2 nm in each case. When successfully hosted into LDH interlayer space, the electrochemical behavior of each hybrid assembly was scrutinized separately in aqueous electrolyte to characterize the redox reaction occurring upon cycling and found to be a rapid faradic type. Both electrode materials were placed face to face to achieve a new aqueous battery (16C rate) that provides a first cycle-capacity of about 7 mAh per gram of working electrode material LDH/FCm at 10 mV/s over a voltage window of 2.2 V in 1M sodium acetate, thus validating the hybrid LDH host approach on both electrode materials even if the cyclability of the assembly has not yet been met.
Published: 2023

43. Development and Validation of a new formulation of Hybrid Temporal Large-Eddy Simulation

Author: Duffal, Vladimir, Manceau, Remi, de Laage de Meux, Benoit, Mécanique des Fluides, Energies et Environnement (EDF R&D MFEE), EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Laboratoire de Mathématiques et de leurs Applications [Pau] (LMAP), Université de Pau et des Pays de l'Adour (UPPA)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS), Computational AGility for internal flows sImulations and compaRisons with Experiments (CAGIRE), Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Pau et des Pays de l'Adour (UPPA), and ANR-17-CE06-0005,MONACO_2025,Modélisation de la convection naturelle : un défi pour l'ambition Tout Numérique 2025(2017)
Subjects: [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph]
Abstract: International audience
Published: 2023

44. On the coalitional decomposition of parameters of interest

Author: Idrissi, Marouane Il, Bousquet, Nicolas, Gamboa, Fabrice, Iooss, Bertrand, Loubes, Jean-Michel, Performance, Risque Industriel, Surveillance pour la Maintenance et l’Exploitation (EDF R&D PRISME), EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Institut de Mathématiques de Toulouse UMR5219 (IMT), Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Saclay Industrial Lab for Artificial Intelligence Research (SINCLAIR AI Lab), THALES [France]-TOTAL FINA ELF-EDF (EDF), Laboratoire de Probabilités, Statistique et Modélisation (LPSM (UMR_8001)), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Méthodes d'Analyse Stochastique des Codes et Traitements Numériques (GdR MASCOT-NUM), and Centre National de la Recherche Scientifique (CNRS)
Subjects: Methodology (stat.ME), FOS: Computer and information sciences, sensitivity analysis, probability theory, statistics, [MATH.MATH-ST]Mathematics [math]/Statistics [math.ST], combinatorics, FOS: Mathematics, Mathematics - Statistics Theory, Statistics Theory (math.ST), interpretability, [STAT.ME]Statistics [stat]/Methodology [stat.ME], Statistics - Methodology
Abstract: Understanding the behavior of a black-box model with probabilistic inputs can be based on the decomposition of a parameter of interest (e.g., its variance) into contributions attributed to each coalition of inputs (i.e., subsets of inputs). In this paper, we produce conditions for obtaining unambiguous and interpretable decompositions of very general parameters of interest. This allows to recover known decompositions, holding under weaker assumptions than stated in the literature.
Published: 2023

45. Revisiting facet nucleation under mixed mode I+III loading with T-stress and mode-dependent fracture properties

Author: Aurélien Doitrand, Dominique Leguillon, Gergely Molnár, Véronique Lazarus, Matériaux, ingénierie et science [Villeurbanne] (MATEIS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Institut Jean Le Rond d'Alembert (DALEMBERT), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Mécanique des Contacts et des Structures [Villeurbanne] (LaMCoS), Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la mécanique et Applications industrielles (IMSIA - UMR 9219), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École Nationale Supérieure de Techniques Avancées (ENSTA Paris)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-EDF R&D (EDF R&D), and EDF (EDF)-EDF (EDF)
Subjects: [PHYS]Physics [physics], Mechanics of Materials, Modeling and Simulation, Crack front segmentation, Computational Mechanics, T-stress, Crack nucleation, Mode I+III
Abstract: We study the problem of crack front segmentation into facets under mixed mode I+III loading. Discrete facet network nucleation is determined based on the match asymptotic expansion approach of the coupled criterion considering both the influence of T-stress (parallel to the initial crack front) and modedependent fracture properties. We show that considering exclusively either T-stress or mode dependent properties, facet nucleation may be more favorable than straight crack propagation but in conditions that are incompatible with experimental observations. It is only by coupling mode-dependent fracture properties with T-stress that we are able to determine configurations compatible with experimental observations for which facet nucleation is more likely to occur than straight crack propagation. These configurations depend on the T-stress magnitude and critical shear energy release rate. We thus highlight that crack front segmentation into facets is material and loading dependent phenomenon that is not related to a sole mode mixity threshold but also to T-stress magnitude and shear critical energy release rate.
Published: 2023

46. Homogenized transition conditions for plasmonic metasurfaces

Author: Nicolas Lebbe, Agnès Maurel, Kim Pham, Institut Langevin - Ondes et Images (UMR7587) (IL), Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la mécanique et Applications industrielles (IMSIA - UMR 9219), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École Nationale Supérieure de Techniques Avancées (ENSTA Paris)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), ANR-10-IDEX-0001,PSL,Paris Sciences et Lettres(2010), ANR-19-CE08-0006,METARESO,Propagation d'ondes dans des Métamatériaux Résonants(2019), and ANR-10-LABX-0024,WIFI,Institut Langevin : Ondes et Images, du Fondamental à l'Innovation(2010)
Subjects: [PHYS]Physics [physics], surface plasmons, metasurfaces, plasmonics
Abstract: International audience; The present study aims to model the optical response of plasmonic metasurfaces made of a periodic arrangement of metallic particles with arbitrary shape and subwavelength dimensions. By combining homogenization with quasistatic plasmonic eigenmode expansion, the metasurface is replaced by a zero-thickness interface associated with frequency-dependent effective susceptibilities. The resulting discontinuities of the fields are responsible for strong interaction with the incoming light at the resonances when the complex permittivity of the metal passes close to the real permittivity of an eigenmode. Our modeling provides a physical picture of resonances in plasmonic metasurfaces, and it allows for a huge decrease in the numerical cost of their computations. In addition, comparisons with direct numerics in two dimensions evidence its predictive force at any incidence, particle shape, and arrangement.
Published: 2023

47. Tracking a killer shrimp: Dikerogammarus villosus invasion dynamics across Europe

Author: Ismael Soto, Ross N. Cuthbert, Danish A. Ahmed, Antonín Kouba, Sami Domisch, Jaime R. G. Marquez, Ayah Beidas, Giuseppe Amatulli, Jens Kiesel, Longzhu Q. Shen, Margarita Florencio, Herlander Lima, Elizabeta Briski, Florian Altermatt, Gaït Archambaud‐Suard, Peter Borza, Zoltan Csabai, Thibault Datry, Mathieu Floury, Maxence Forcellini, Jean‐François Fruget, Patrick Leitner, Marie‐Hélène Lizée, Anthony Maire, Anthony Ricciardi, Ralf B. Schäfer, Rachel Stubbington, Gea H. Van der Lee, Gábor Várbíró, Ralf C. M. Verdonschot, Peter Haase, Phillip J. Haubrock, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses [University of South Bohemia] (CENAKVA), Faculty of Fisheries and Protection of Waters [University of South Bohemia], University of South Bohemia -University of South Bohemia, Helmholtz Centre for Ocean Research [Kiel] (GEOMAR), Queen's University [Belfast] (QUB), Gulf University for Science and Technology (GUST), Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Yale University [New Haven], Christian-Albrechts University of Kiel, Risques, Ecosystèmes, Vulnérabilité, Environnement, Résilience (RECOVER), Aix Marseille Université (AMU)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), RiverLy - Fonctionnement des hydrosystèmes (RiverLy), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Laboratoire d'Ecologie des Hydrosystèmes Naturels et Anthropisés (LEHNA), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École Nationale des Travaux Publics de l'État (ENTPE)-Centre National de la Recherche Scientifique (CNRS), ARALEP, Laboratoire National d’Hydraulique et Environnement (EDF R&D LNHE), EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Universität Duisburg-Essen = University of Duisburg-Essen [Essen], Senckenberg Research Institute and Natural History Museum [Frankfurt], Senckenberg – Leibniz Institution for Biodiversity and Earth System Research - Senckenberg Gesellschaft für Naturforschung, Leibniz Association-Leibniz Association, Leverhulme TrustECF-2021-001, Federal Ministry of Education & Research (BMBF)033W034A, European Project: 871128,eLTER PLUS (2020), UNIVERSITY OF SOUTH BOHEMIA CESKE BUDEJOVICE CZE, Partenaires IRSTEA, Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), and Kuwait Foundation for the Advancement of Sciences (KFAS)PR1914SM-01
Subjects: invasive alien species, Water and Food, time-series, [SDE.MCG]Environmental Sciences/Global Changes, long-term monitoring, Water en Voedsel, biological invasion, freshwater ecosystem, SDG 3 - Good Health and Well-being, [SDE]Environmental Sciences, crustacean, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Biologie, Ecology, Evolution, Behavior and Systematics, SDG 15 - Life on Land
Abstract: AimInvasive alien species are a growing problem worldwide due to their ecological, economic and human health impacts. The “killer shrimp” Dikerogammarus villosus is a notorious invasive alien amphipod from the Ponto-Caspian region that has invaded many fresh and brackish waters across Europe. Understandings of large-scale population dynamics of highly impactful invaders such as D. villosus are lacking, inhibiting predictions of impact and efficient timing of management strategies. Hence, our aim was to assess trends and dynamics of D. villosus as well as its impacts in freshwater rivers and streams.LocationEurope.MethodsWe analysed 96 European time series between 1994 and 2019 and identified trends in the relative abundance (i.e. dominance %) of D. villosus in invaded time series, as well as a set of site-specific characteristics to identify drivers and determinants of population changes and invasion dynamics using meta-regression modelling. We also looked at the spread over space and time to estimate the invasion speed (km/year) of D. villosus in Europe. We investigated the impact of D. villosus abundance on recipient community metrics (i.e. abundance, taxa richness, temporal turnover, Shannon diversity and Pielou evenness) using generalized linear models.ResultsPopulation trends varied across the time series. Nevertheless, community dominance of D. villosus increased over time across all time series. The frequency of occurrences (used as a proxy for invader spread) was well described by a Pareto distribution, whereby we estimated a lag phase (i.e. the time between introduction and spatial expansion) of approximately 28 years, followed by a gradual increase before new occurrences declined rapidly in the long term. D. villosus population change was associated with decreased taxa richness, community turnover and Shannon diversity.Main ConclusionOur results show that D. villosus is well-established in European waters and its abundance significantly alters ecological communities. However, the multidecadal lag phase prior to observed spatial expansion suggests that initial introductions by D. villosus are cryptic, thus signalling the need for more effective early detection methods.
Published: 2023

48. A hybrid shell-beam element for straight thin-walled tubular structures

Author: Pascal-Abdellaoui, Y., Daude, F., Stolz, Claude, Lafon, P., Galon, P., Institut des Sciences de la mécanique et Applications industrielles (IMSIA - UMR 9219), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École Nationale Supérieure de Techniques Avancées (ENSTA Paris)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), EDF R&D (EDF R&D), EDF (EDF), CEA- Saclay (CEA), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: shell kinematics, explicit time integration, straight thin-walled tubes, [SPI.MECA.MSMECA]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Materials and structures in mechanics [physics.class-ph], Finite-Element method, Beam kinematics
Abstract: International audience; A novel beam model is proposed in order to consider deformations of its cross-section in the context of straight thin-walled tubes. For this purpose, the straight beam kinematics is enriched by addition of orthogonal shell-type displacement field of the tube section. The considered displacement field is composed of three contributions: classical linear beam and linear shell terms in conjunction with the non-linear coupling between local deformation of the section and its global rotation. Both Euler-Bernoulli and Love-Kirchhoff hypotheses for beam and shell kinematics, respectively, are adopted as well as the thin-walled assumption. First-order shear deformation for the radial variable and Fourier expansion in terms of the circumferential variable are also considered for the mid-surface displacement field. Then, the stress tensor is obtained under plane stress conditions. The virtual power principle is finally used to obtain the equations of motion satisfied by the corresponding generalized forces. Afterwards, an explicit updated Lagrangian Finite-Element approach using a lumped mass matrix is proposed for solving the tube governing equations and the stability condition of the time integration is given. Test-cases are then chosen to assess the present tube finiteelement. Both static and dynamic problems are considered. First, the proposed model is compared to analytical solutions. Finally, a tube subjected to a distributed patch loading is studied. The influence of the number of Fourier modes, of warping and coupling terms is examined. The proposed model makes it possible to retrieve classical shell solution of the cross-section deformation with significant computational savings.
Published: 2023

49. On the use of a local $\hat R$ to improve MCMC convergence diagnostic

Author: Moins, Théo, Arbel, Julyan, Dutfoy, Anne, Girard, Stéphane, Modèles statistiques bayésiens et des valeurs extrêmes pour données structurées et de grande dimension (STATIFY), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), PERformance et prévention des Risques Industriels du parC par la simuLation et les EtudeS (EDF R&D PERICLES), EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Chaire Stress Test - BNP Paribas/Ecole polytechnique/Fondation de l'X., and Moins, Théo
Subjects: [STAT]Statistics [stat], [STAT] Statistics [stat]
Abstract: Diagnosing convergence of Markov chain Monte Carlo is crucial and remains an essentially unsolved problem. Among the most popular methods, the potential scale reduction factor, commonly named $\hat R$, is an indicator that monitors the convergence of output chains to a target distribution, based on a comparison of the between-and within-variances. Several improvements have been suggested since its introduction in the 90s. Here, we aim at better understanding the $\hat R$ behaviour by proposing a localized version that focuses on quantiles of the target distribution. This new version relies on key theoretical properties of the associated population value. It naturally leads to proposing a new indicator $\hat R_\infty$, which is shown to allow both for localizing the Markov chain Monte Carlo convergence in different quantiles of the target distribution, and at the same time for handling some convergence issues not detected by other $\hat R$ versions.
Published: 2023

50. Shapley effects and proportional marginal effects for global sensitivity analysis: application to computed tomography scan organ dose estimation

Author: Foucault, Anais, Il Idrissi, Marouane, Iooss, Bertrand, Ancelet, Sophie, Laboratoire d épidémiologie des rayonnements ionisants (IRSN/PSE-SANTE/SESANE/LEPID), Service de recherche sur les effets biologiques et Sanitaires des rayonnements ionisants (IRSN/PSE-SANTE/SESANE), Institut de Radioprotection et de Sûreté Nucléaire (IRSN)-Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Performance, Risque Industriel, Surveillance pour la Maintenance et l’Exploitation (EDF R&D PRISME), EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Institut de Mathématiques de Toulouse UMR5219 (IMT), Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Saclay Industrial Lab for Artificial Intelligence Research (SINCLAIR AI Lab), THALES [France]-TOTAL FINA ELF-EDF (EDF), Méthodes d'Analyse Stochastique des Codes et Traitements Numériques (GdR MASCOT-NUM), and Centre National de la Recherche Scientifique (CNRS)
Subjects: FOS: Computer and information sciences, [STAT.AP]Statistics [stat]/Applications [stat.AP], Epidemiology, Proportional marginal effects, Radiation dose, Applications (stat.AP), Shapley effects, Statistics - Applications, Simulation
Abstract: Concerns have been raised about possible cancer risks after exposure to computed tomography (CT) scans in childhood. The health effects of ionizing radiation are then estimated from the absorbed dose to the organs of interest which is calculated, for each CT scan, from dosimetric numerical models, like the one proposed in the NCICT software. Given that a dosimetric model depends on input parameters which are most often uncertain, the calculation of absorbed doses is inherently uncertain. A current methodological challenge in radiation epidemiology is thus to be able to account for dose uncertainty in risk estimation. A preliminary important step can be to identify the most influential input parameters implied in dose estimation, before modelling and accounting for their related uncertainty in radiation-induced health risks estimates. In this work, a variance-based global sensitivity analysis was performed to rank by influence the uncertain input parameters of the NCICT software implied in brain and red bone marrow doses estimation, for four classes of CT examinations. Two recent sensitivity indices, especially adapted to the case of dependent input parameters, were estimated, namely: the Shapley effects and the Proportional Marginal Effects (PME). This provides a first comparison of the respective behavior and usefulness of these two indices on a real medical application case. The conclusion is that Shapley effects and PME are intrinsically different, but complementary. Interestingly, we also observed that the proportional redistribution property of the PME allowed for a clearer importance hierarchy between the input parameters.
Published: 2023
Full Text: View/download PDF

Catalog

Books, media, physical & digital resources

See catalog results

Searchworks

Select search scope, currently: Articles Catalog books, media & more in Jio Institute collections Articles journal articles & other e-resources

Search

Search Constraints

Refine your results

Search Limiters

Topic

Publication Year Range

Language

Publication Type

Journal

Database

Publisher

7,072 results on '"EDF ( EDF )"'

Search Results

Catalog

Select search scope, currently: Articles

Catalog

books, media & more in Jio Institute collections

Articles

journal articles & other e-resources