Author: "A, Pradalier" / Publisher: hal ccsd - Searchworks@Jio Institute Digital Library Search Results

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160 results on '"A, Pradalier"'

1. Kinetic plasma-sheath self-organization

Author: Munschy, Yann, Bourne, Emily, Dif-Pradalier, Guilhem, Donnel, Peter, Ghendrih, Philippe, Grandgirard, Virginie, Sarazin, Yanick, Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and European Project: 824158,H2020-EU.1.4. - EXCELLENT SCIENCE - Research Infrastructures ,EoCoE-II(2019)
Subjects: Kinetic, [PHYS]Physics [physics], Sheath, simulation, Plasma physics, Plasma wall interaction
Abstract: The interaction between a plasma and a solid surface is studied in a (1D-1V) kinetic framework using a localized particle and convective energy source. Matching the quasineutral plasma region and sheath horizon is addressed in the fluid framework with a zero heat flux closure. It highlights non-polytropic nature of the physics of parallel transport. Shortfalls of this approach compared to a reference kinetic simulation, highlighting the importance of the heat flux, leads to addressing the sound velocity, non-collisional closure and higher moment closure. No gain in the predictive capability is obtained. The kinetic constraint at the sheath horizon is discussed and modified to account for conditions that are actually met in simulations, namely quasineutrality with a small but finite charge density. Analyzing the distribution functions shows that collisional transfer is mandatory to achieve steady-state self-organization on the open field lines.
Published: 2023

2. Gyrokinetic turbulence studies of the transition from open to closed field lines in tokamaks

Author: Donnel, Peter, Dif Pradalier, G., G. Di, Giannatale, Villard, L., V., Grandgirard, Nguyen, L., K., Obrejan, E., Bourne, X., Garbet, P., Ghendrih, Munschy, Yann, Y., Sarazin, R., Varennes, Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Swiss Plasma Center (SPC), Ecole Polytechnique Fédérale de Lausanne (EPFL), DAM Île-de-France (DAM/DIF), 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), and icard, valerie
Subjects: [PHYS]Physics [physics], [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], [PHYS.PHYS.PHYS-PLASM-PH] Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], [PHYS] Physics [physics]
Abstract: International audience
Published: 2022

3. Physics of E x B staircases

Author: Dif-Pradalier, G., Clairet, F., Diamond, P., Donnel, P., Garbet, X., Ghendrih, V., Grandgirard, A., Medvedeva, A., Milovanov, A., Sarazin, Y., Vermare, L., Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), University of California [San Diego] (UC San Diego), University of California (UC), UCSD-CNRS Joint Research Chemistry Laboratory (UMI 3555), University of California (UC)-University of California (UC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), CEA Cadarache, Laboratoire de Mécanique, Modélisation et Procédés Propres (M2P2), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), Italian National agency for new technologies, Energy and sustainable economic development [Frascati] (ENEA), Laboratoire de Physique des Plasmas (LPP), Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
Subjects: [PHYS]Physics [physics], [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph]
Abstract: International audience
Published: 2022

4. Author Correction: Transport barrier onset and edge turbulence shortfall in fusion plasmas. [Communications Physics 5, 259 (2022)]

Author: Guilhem Dif-Pradalier, Philippe Ghendrih, Yanick Sarazin, Elisabetta Caschera, Frédéric Clairet, Yann Camenen, Peter Donnel, Xavier Garbet, Virginie Grandgirard, Yann Munschy, Laure Vermare, Fabien Widmer, Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Physique des interactions ioniques et moléculaires (PIIM), and Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Plasma Physics (physics.plasm-ph), Physics::Fluid Dynamics, Physics::Plasma Physics, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], Physics::Space Physics, General Physics and Astronomy, FOS: Physical sciences, Physics - Plasma Physics
Abstract: Magnetic confinement fusion offers the promise of sustainable and safe energy production on Earth. Advanced experimental scenarios exploit the fascinating yet uncommon ability of confined plasmas to bifurcate into states of enhanced performance upon application of additional free energy sources. Self-regulation of small-scale turbulent eddies is essential to accessing these improved regimes. However, after several decades, basic principles for these bifurcations are still largely debated and clarifications from first principles lacking. We show here, computed from the primitive kinetic equations, establishment of a state of improved confinement through self-organisation of plasma microturbulence. Our results highlight the critical role of the interface between plasma and material boundaries and demonstrate the importance of propagation of turbulence activity beyond regions of convective drive. These observations strongly suggest a paradigm shift where the magnetised plasma at the onset of enhanced performance self-organises into a globally critical state, ‘nonlocally’ controlled by fluxes of turbulence activity.
Published: 2022

5. Role of avalanche transport in competing drift wave and interchange turbulence

Author: Ghendrih, Philippe, Dif-Pradalier, Guilhem, Panico, Olivier, Sarazin, Yanick, Bufferand, Hugo, Ciraolo, Guido, Donnel, Peter, Fedorczak, Nicolas, Garbet, Xavier, Grandgirard, Virginie, Hennequin, Pascale, Serre, Eric, Tamain, Patrick, Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), École polytechnique (X), Centre National de la Recherche Scientifique (CNRS), and Aix Marseille Université (AMU)
Subjects: History, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], Computer Science Applications, Education
Abstract: We complete the 2D 2-fields turbulence model previously used with an interchange-like instability by slightly modifying the parallel loss terms to drive drift wave instabilities. We show that the instability driven by temperature fluctuations of the sheath losses is identical to that of the drift wave turbulence. The linear analysis is performed and used to select control parameters that yield identical maximum growth rates for the interchange alone and drift wave alone instability. Combining the two instabilities doubles the maximum growth rate. The non-linear simulations are used to analyse the SOL width. The simulations allow one to identify a low field side SOL region where interchange and drift wave are unstable and a high field side SOL region where only the drift wave is unstable. The SOL profiles appear exponential in the region close to the source but depart from a simple exponential fall-off in the far SOL. The low field side SOL width is found to be larger in the interchange alone case, slightly smaller when both instabilities are present and finally narrower when only the drift waves. For the high field side SOL, without interchange, the drift wave SOL width is observed to be identical to that on the low field side and larger than that when both instabilities at play. The Sherwood dimensionless parameter, ratio of convective particle flux divided by the diffusive particle flux, is used to compare the efficiency of turbulent transport. The profiles of the Sherwood parameter for time and flux surface averaged transport indicate that turbulent transport is dominant close to the separatrix but is less effective towards the far SOL. The Sherwood parameter evolution, determined with the flux-surface averaged transport, indicates that outward avalanche transport with corrugations governs the case with interchange only. When combining the two instabilities, outward avalanche transport is less pronounced and inward avalanche transport is observed, reducing the overall turbulent transport efficiency. The avalanche transport with drift waves only compared to interchange only is found to be inhibited.
Published: 2022

6. Unraveling the competition/synergy between turbulence and 3D magnetic perturbations

Author: Varennes, Robin, Garbet, Xavier, Bourne, Emilie, Vermare, L., Sarazin, Yanick, Dif-Pradalier, Guilhem, Grandgirard, Virginie, Ghendrih, Philippe, Donnel, Peter, Peret, Mathieu, Obrejan, Kevin, Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire de Physique des Plasmas (LPP), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and icard, valerie
Subjects: [NLIN] Nonlinear Sciences [physics], [NLIN]Nonlinear Sciences [physics]
Abstract: International audience
Published: 2022

7. New advances to prepare GYSELA-X code for exascale global gyrokinetic plasma turbulence simulations: porting on GPU and ARM architectures

Author: Grandgirard, Virginie, Obrejan, Kevin, Midou, Dorian, Asahi, Y, Bernard, P-E, Bigot, J, Bourne, E, Dechard, J, Dif- Pradalier, G, Donnel, P, Garbet, X, Gueroudji, A, Hager, G, Murai, H, Ould-Ruis, Yacine, Padioleau, T, Nguyen, L, Peybernes, M, Sarazin, Y, Sato, M, Tsuji, M, Vezolle, P, Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Japan Atomic Energy Agency, Hewlett Packard Enterprise (Hewlett Packard) (HPE), Maison de la Simulation (MDLS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut National de Recherche en Informatique et en Automatique (Inria)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), AS+ Groupe EOLEN, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), RIKEN Center for Computational Science [Kobe] (RIKEN CCS), RIKEN - Institute of Physical and Chemical Research [Japon] (RIKEN), 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), Ecole Polytechnique Fédérale de Lausanne (EPFL), the Association for Computing Machinery (ACM), and the Swiss National Supercomputing Centre (CSCS)
Subjects: [NLIN]Nonlinear Sciences [physics]
Abstract: International audience
Published: 2022

8. Impact of magnetic ripple on neoclassical equilibrium in gyrokinetic simulations

Author: R Varennes, X Garbet, L Vermare, Y Sarazin, G Dif-Pradalier, V Grandgirard, P Ghendrih, P Donnel, M Peret, K Obrejan, E Bourne, Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire de Physique des Plasmas (LPP), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Varennes, Robin
Subjects: stochastic transport, Nuclear Energy and Engineering, neoclassical transport, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], [PHYS.PHYS.PHYS-PLASM-PH] Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], plasma flow, Condensed Matter Physics
Abstract: The effect of magnetic field ripple on tokamak plasma without turbulence is studied numerically and augmented with a reduced analytical model that includes neoclassical processes in the presence of non-axisymmetric perturbation and stochastic transport. For this study, a magnetic field ripple perturbation has been implemented in the GYSELA gyrokinetic code. This implementation has been verified thanks to a test of toroidal angular momentum conservation. The GYSELA code was then successfully benchmarked against the NEO code, which solves the drift kinetic equation, and against the reduced model in the collisionality range ν ⋆ ∈ [0.05–0.5] for several amplitudes of the magnetic ripple. An observation, shared by the model, the NEO code and GYSELA simulations is that the thermal drive of the mean poloidal velocity—measured by the k V P coefficient—decreases sharply for large yet experimentally relevant magnetic ripple amplitudes, and may even change sign.
Published: 2022

9. A Graph-based Approach to the Initial Guess of UWB Anchor Self-Calibration

Author: Pradalier, Cedric, Richard, Antoine, Schroepfer, Pete, Georgia Tech Lorraine [Metz], Ecole Nationale Supérieure des Arts et Metiers Metz-Georgia Institute of Technology [Atlanta]-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), and European Project: H2020 project BugWright2
Subjects: UWB, Localization, [INFO.INFO-RB]Computer Science [cs]/Robotics [cs.RO], [SCCO.COMP]Cognitive science/Computer science, [INFO.INFO-CG]Computer Science [cs]/Computational Geometry [cs.CG], Triangulation
Abstract: This article considers the challenge of recovering an initial topology of a mesh of devices based on noisy and incomplete measurements of their inter-distances. In comparison to earlier approaches, this paper provides a first guess of the topology, as opposed to recovering a precise geometry of each device. Using a graph-based model of the problem and properties of the 2D and 3D simplices, we show: (a) a topologically correct solution can be recovered when the solution is unique; (b) we can identify which vertices cannot be recovered and why, using a graph structure; and (c) the challenges due to local symmetries in making the solution nonunique. Results in simulation and with a mesh of UWB anchors demonstrate the applicability of the approach.
Published: 2022

10. Formation of the radial electric field profile in the WEST tokamak

Author: L. Vermare, P. Hennequin, C. Honoré, M. Peret, G. Dif-Pradalier, X. Garbet, J. Gunn, C. Bourdelle, F. Clairet, J. Morales, R. Dumont, M. Goniche, P. Maget, R. Varennes, the WEST Team, Laboratoire de Physique des Plasmas (LPP), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: Physics, [PHYS]Physics [physics], Nuclear and High Energy Physics, Tokamak, law, Electric field, Condensed Matter Physics, ComputingMilieux_MISCELLANEOUS, Computational physics, law.invention
Abstract: Sheared flows are known to reduce turbulent transport by decreasing the correlation length and/or intensity of turbulent structures. The transport barrier that takes place at the edge during improved regimes such as H mode, corresponds to the establishment of a large shear of the radial electric field. In this context, the radial shape of the radial electric field or more exactly of the perpendicular E × B velocity appears as a key element in accessing improved confinement regimes. In this paper, we present the radial profile of the perpendicular velocity measured using Doppler back-scattering system at the edge of the plasma, dominated by the E × B velocity, during the first campaigns of the WEST tokamak. It is found that the radial velocity profile is clearly more sheared in lower single null configuration (with the B × ∇B magnetic drift pointing toward the active X-point) than in upper single null configuration for ohmic and low current plasmas (B = 3.7 T and q 95 = 4.7), consistently with the expectation comparing respectively ‘favourable’ versus ‘unfavourable’ configuration. Interestingly, this tendency is sensitive to the plasma current and to the amount of additional heating power leading to plasma conditions in which the E × B velocity exhibits a deeper well in USN configuration. For example, while the velocity profile exhibits a clear and deep well just inside the separatrix concomitant with the formation of a density pedestal during L–H transitions observed in LSN configuration, deeper E r wells are observed in USN configuration during similar transitions with less pronounced density pedestal.
Published: 2022

11. Effet des pesticides sur la morphologie des diatomées benthiques d'eau douce : le cas du glyphosate

Author: Chéron, Sarah, Venkataramanan, Aishwarya, Martinez, Clara, Hamon, Huyên Phong, Heudre, David, Pradalier, Cédric, Usseglio-Polatera, Philippe, Devin, Simon, Felten, Vincent, Laviale, Martin, and Laviale, Martin
Subjects: [SDE.BE] Environmental Sciences/Biodiversity and Ecology, Glyphosate, [SDV.EE] Life Sciences [q-bio]/Ecology, environment, Diatomées, Analyse d'images, AMPA, Morphologie
Abstract: La directive-cadre sur l'eau stipule que les masses d'eau doivent atteindre le "bon état écologique" dans l'UE. Bien que de nombreux indicateurs existent, ils ne sont pas toujours en mesure de révéler les effets subtils d'une faible pression épisodique sur de longues durées d'exposition. Il est donc essentiel de développer des indicateurs d'alerte précoce de la qualité des eaux de surface. A cet effet, l'étude des biofilms phototrophes semble particulièrement pertinente en raison de leur rôle majeur dans les écosystèmes aquatiques. Au sein de ces biofilms, les diatomées occupent une place particulière, puisqu'elles sont déjà intégrées dans la batterie d'outils d'évaluation de la qualité des eaux de surface. Parmi les différents paramètres sur lesquels repose la détermination de la classe de qualité, l'observation de formes tératologiques (déformation des frustules, irrégularité des stries...) est considérée comme révélateur d'un stress [1]. Toutefois, ces déformations sont difficiles à identifier et à dénombrer, et il est également délicat d'en qualifier l'intensité. Il en résulte que cet élément de l'Indice Biologique Diatomées (IBD) est mal renseigné. Il apparait donc nécessaire de développer une méthodologie standardisée pour réaliser les différentes étapes de détection et caractérisation des déformations des diatomées. Dans cette étude, nous présentons les premiers résultats de mise au point d'une telle approche, à partir de bioessais de laboratoire,réalisés sur la diatomée benthique d'eau douce Nitzschia palea. Dans un premier temps, la culture a été exposée à court terme (7 jours) au glyphosate et à son principal produit de dégradation (AMPA) afin de déterminer les concentrations de contaminants inhibant 5, 10 et 50% de leur croissance (valeurs IC5, IC10 et IC50). Ces concentrations et une concentration environnementale ont ensuite été utilisées pour exposer les cultures dans des conditions semi-statiques pendant 28 jours afin d'évaluer le potentiel tératogène du glyphosate et de l'AMPA sur la morphologie des diatomées. Pour chaque échantillon, des images ont été acquises au microscope optique et la morphologie des cellules a été analysée à l'aide de différents descripteurs en lien avec la taille et la forme des cellules. Ces descripteurs ont ensuite été mis en relation avec les déformations observées qui ont été analysées qualitativement (type de déformations) et quantitativement (abondance relative, sévérité). Enfin, cette approche manuelle est comparée à une approche basée sur l'intelligence artificielle en cours de développement permettant de caractériser automatiquement les effets de ces contaminants sur la morphologie des diatomées
Published: 2022

12. Intrinsic rotation drive in tokamaks: the competition between turbulence and magnetic braking

Author: Varennes, R, Garbet, X, Vermare, L., Sarazin, Y, Dif-Pradalier, G, Grandgirard, V, Ghendrih, P, Donnel, P, Peret, M, Obrejan, K, Bourne, E, Varennes, Robin, Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire de Physique des Plasmas (LPP), Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
Subjects: [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], [PHYS.PHYS.PHYS-PLASM-PH] Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph]
Abstract: This workshop is devoted to the theory of magnetic confinement systems; International audience
Published: 2022

13. Interplay between magnetic braking and turbulent stress tensor regarding plasma flow

Author: Varennes, R, Gendrih, P, Vermare, L., Garbet, X, Sarazin, Y, Grandgirard, V, Dif- Pradalier, G, Donnel, P, Peret, M, Varennes, Robin, Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire de Physique des Plasmas (LPP), Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
Subjects: [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], [PHYS.PHYS.PHYS-PLASM-PH] Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph]
Abstract: International audience
Published: 2022

14. Synergy of turbulent momentum drive and magnetic braking

Author: Varennes, R., Garbet, X., Vermare, L., Sarazin, Y., Dif-Pradalier, G., Grandgirard, V., Ghendrih, P., Donnel, P., Peret, M., Obrejan, K., Bourne, E., Varennes, Robin, Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire de Physique des Plasmas (LPP), Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
Subjects: [PHYS]Physics [physics], [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], [PHYS.PHYS.PHYS-PLASM-PH] Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], General Physics and Astronomy
Abstract: In absence of external torque, plasma rotation in tokamaks results from a balance between collisional magnetic braking and turbulent drive. The outcome of this competition and cooperation is essential to determine the plasma flow. A reduced model, supported by gyrokinetic simulations, is first used to explain and quantify the competition only. The ripple amplitude above which magnetic drag overcomes turbulent viscosity is obtained. The synergetic impact of ripple on the turbulent toroidal Reynolds stress is explored. Simulations show that the main effect comes from an enhancement of the radial electric field shear by the ripple, which in turn impacts the residual stress.
Published: 2022

15. Safety factor impact on the radial electric field in gyrokinetic simulations

Author: Varennes, R, Peret, M, Vermare, L., Garbet, X, Sarazin, Y, Grandgirard, V, Dif- Pradalier, G, Gendrih, P, Donnel, P, Varennes, Robin, Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire de Physique des Plasmas (LPP), Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
Subjects: [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], [PHYS.PHYS.PHYS-PLASM-PH] Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph]
Abstract: International audience
Published: 2022

16. The use of remote sensing tools for accurate charcoal kilns’ inventory and distribution analysis: Comparative assessment and prospective

Author: Cláudia Oliveira, Stéphanie Aravecchia, Cédric Pradalier, Vincent Robin, Simon Devin, Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC), Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Terre et Environnement de Lorraine (OTELo), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Georgia Tech Lorraine [Metz], Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Georgia Institute of Technology [Atlanta]-CentraleSupélec-Ecole Nationale Supérieure des Arts et Metiers Metz-Centre National de la Recherche Scientifique (CNRS), and ANR-15-IDEX-0004,LUE,Isite LUE(2015)
Subjects: 010506 paleontology, Global and Planetary Change, LiDAR, 060102 archaeology, Spatial analysis, Deep learning, 06 humanities and the arts, 15. Life on land, Management, Monitoring, Policy and Law, Charcoal kiln, 01 natural sciences, [SPI.AUTO]Engineering Sciences [physics]/Automatic, 13. Climate action, Automatic detection, 0601 history and archaeology, Computers in Earth Sciences, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, 0105 earth and related environmental sciences, Earth-Surface Processes
Abstract: International audience; Historical charcoal production is one of the significant factors affecting today’s forest dynamics. A key challenge is to develop tools to investigate historical charcoal production over large areas, allowing a more comprehensive understanding of past impacts and history of charcoal production over a given landscape. In this study, high-resolution remote-sensing airborne LiDAR images over a large woodland area were used to compare manual on-screen versus algorithm-based automatic methods to inventory charcoal kilns with inputs of field-validated data. The results revealed that (1) the on-screen detection method provided less false-positives, (2) the automatic method detects a higher number of kilns and (3) kiln distribution seemed to be connected mostly to land ownership rather than to environmental variables. This study validates a new method of charcoal kilns’ inventory and spatial analysis that can be applied to other areas to better understand the effect of past biomass harvesting for charcoal production on forest dynamics.
Published: 2021

17. Interface transport barriers in magnetized plasmas

Author: Claudia Norscini, Thomas Cartier-Michaud, Guilhem Dif-Pradalier, Xavier Garbet, Philippe Ghendrih, Virginie Grandgirard, Yanick Sarazin, Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: [PHYS.PHYS.PHYS-COMP-PH]Physics [physics]/Physics [physics]/Computational Physics [physics.comp-ph], [PHYS.PHYS.PHYS-FLU-DYN]Physics [physics]/Physics [physics]/Fluid Dynamics [physics.flu-dyn], [PHYS.PHYS.PHYS-CLASS-PH]Physics [physics]/Physics [physics]/Classical Physics [physics.class-ph], Nuclear Energy and Engineering, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], Physics::Space Physics, [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph], [PHYS.COND.CM-SM]Physics [physics]/Condensed Matter [cond-mat]/Statistical Mechanics [cond-mat.stat-mech], Condensed Matter Physics
Abstract: We address the formation of Interface Transport Barriers using a generic turbulent transport model, reduced to 2D, and used to investigate interchange turbulence in magnetized plasmas. The generation of a transport barrier at the edge-scrape off layer (SOL) plasma interface is governed by a zonation regime in the edge region with closed-field lines. The barrier is triggered by a gap in the turbulent spectrum between zero, the zonal flow wave vector, and the wave vector of the spectrum maximum. This gap is controlled by the energy injection wave vector of the interchange instability and the Rhine scale that bounds the inverse cascade. Increasing the magnitude of the turbulence drive at a given gap reinforces the transport barrier. In the interface transport barrier regime, edge relaxation bursts of turbulence regenerate the zonal flows that are eroded by damping processes such as collisions. The duration of the quiescent phase between the quasi-periodic relaxation events is then governed by the ion collision frequency. Such an interface transport barrier can play the role of a seed barrier prior to a full bifurcation to improved confinement.
Published: 2021

18. Filling Gaps in Micro-Meteorological Data

Author: Joseph Tanny, Lior Fine, Offer Rozenstein, Matthieu Geist, Cédric Pradalier, Antoine Richard, Georgia Institute of Technology [Lorraine, France], Agricultural Research Organization - the Volcani Center, Google Research, Georgia Tech Lorraine [Metz], Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Georgia Institute of Technology [Atlanta]-CentraleSupélec-Ecole Nationale Supérieure des Arts et Metiers Metz-Centre National de la Recherche Scientifique (CNRS), and Pradalier, Cedric
Subjects: [SDV.SA]Life Sciences [q-bio]/Agricultural sciences, [SDV.SA] Life Sciences [q-bio]/Agricultural sciences, 0303 health sciences, Gap filling, 010504 meteorology & atmospheric sciences, Computer science, Sampling (statistics), [INFO.INFO-LG] Computer Science [cs]/Machine Learning [cs.LG], Attention-Models, computer.software_genre, 01 natural sciences, Evapo-Transpiration, 03 medical and health sciences, Information extraction, [INFO.INFO-LG]Computer Science [cs]/Machine Learning [cs.LG], Simple (abstract algebra), Data efficiency, Data mining, Marginal distribution, Architecture, computer, Gap-Filling, 030304 developmental biology, 0105 earth and related environmental sciences, Interpolation
Abstract: Filling large data-gaps in Micro-Meteorological data has mostly been done using interpolation techniques based on a marginal distribution sampling. Those methods work well but need a large horizon of the previous events to achieve good results since they do not model the system but only rely on previously encountered iterations. In this paper, we propose to use multi-head deep attention networks to fill gaps in Micro-Meteorological Data. This methodology couples large-scale information extraction with modeling capabilities that cannot be achieved by interpolation-like techniques. Unlike Bidirectional RNNs, our architecture is not recurrent, it is simple to tune and our data efficiency is higher. We apply our architecture to real-life data and clearly show its applicability in agriculture, furthermore, we show that it could be used to solve related problems such as filling gaps in cyclic-multivariate-time-series.
Published: 2020

19. Identification of antibiotics triggering the dissemination of antibiotic resistance genes by SXT/R391 elements using a dedicated high-throughput whole-cell biosensor assay

Author: Christophe Merlin, Hélène Guilloteau, Patrick Billard, Veronica L. Roman, Cédric Pradalier, Xavier Bellanger, Laboratoire de Chimie Physique et Microbiologie pour les Matériaux et l'Environnement (LCPME), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Georgia Tech Lorraine [Metz], Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Georgia Institute of Technology [Atlanta]-CentraleSupélec-Ecole Nationale Supérieure des Arts et Metiers Metz-Centre National de la Recherche Scientifique (CNRS), Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC), Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Terre et Environnement de Lorraine (OTELo), and Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Microbiology (medical), Imipenem, [SDV.BIO]Life Sciences [q-bio]/Biotechnology, medicine.drug_class, Automated data processing, Antibiotics, Computational biology, Biosensing Techniques, Biology, medicine.disease_cause, 03 medical and health sciences, Drug Resistance, Multiple, Bacterial, [INFO.INFO-AU]Computer Science [cs]/Automatic Control Engineering, medicine, Bioluminescence, Pharmacology (medical), Gene, Escherichia coli, 030304 developmental biology, Pharmacology, 0303 health sciences, 030306 microbiology, [SDV.BBM.BM]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Molecular biology, [SDV.MP.BAC]Life Sciences [q-bio]/Microbiology and Parasitology/Bacteriology, Anti-Bacterial Agents, High-Throughput Screening Assays, Infectious Diseases, Conjugation, Genetic, DNA Transposable Elements, Bioreporter, Mobile genetic elements, medicine.drug
Abstract: Background Mobile genetic elements (MGEs) are widely involved in the dissemination of antibiotic resistance genes and some of them, such as the integrative and conjugative element SXT, are even induced by specific antibiotics at sub-lethal concentrations. Objectives This work explores collateral effects of a broad range of antibiotics on the mobility of the SXTMO10 element using a specifically designed high-throughput screening test. Methods Twenty-five promoters involved in the mobility of SXT and six artificial constitutive promoters were transcriptionally fused to luxCDABE bioluminescent genes and introduced into Escherichia coli strains with or without SXT to build whole-cell biosensors for a large-scale screening involving 48 antibiotics. A bioluminescent assay implementing a classical agar diffusion approach was coupled to an automated data processing pipeline developed to extract and analyse luminescence data from over 2000 antibiotic/biosensor combination profiles. Results In addition to quinolones previously reported as inducing the expression of SXT mobility genes, we found that specific antibiotics belonging to other classes, such as imipenem and azithromycin, also behave as inducers. The use of a control set of constitutive biosensors also revealed an unexpected intricate relationship between cell respiration and light production that allowed the identification of antibiotics interfering with the respiration process. Conclusions The effect of antibiotics goes beyond the interaction with their primary cell targets and may lead to adverse effects such as triggering the dissemination of resistance by MGEs, sometimes in unpredictable ways. Identifying such MGE-triggering antibiotics is of prime importance for better controlling collateral effects during therapy.
Published: 2021

20. Combined Grid and Feature-based Mapping of Metal Structures with Ultrasonic Guided Waves

Author: Ouabi, Othmane-Latif, POMAREDE, Pascal, Zeghidour, Neil, Geist, Matthieu, Declercq, Nico, Pradalier, Cédric, Georgia Tech Lorraine [Metz], Centre National de la Recherche Scientifique (CNRS)-CentraleSupélec-Georgia Institute of Technology [Lorraine, France]-Georgia Institute of Technology [Atlanta]-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Ecole Nationale Supérieure des Arts et Metiers Metz-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Google Brain, Paris, and Georgia Institute of Technology [Atlanta]
Subjects: [SPI.ACOU]Engineering Sciences [physics]/Acoustics [physics.class-ph], [INFO.INFO-RB]Computer Science [cs]/Robotics [cs.RO], [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing
Abstract: The ultrasonic mapping of plate-based facilities is an essential step towards the robotic inspection of large metal structures such as storage tanks or ship hulls. This work proposes a novel framework that exploits ultrasonic echoes to recover grid-based and feature-based spatial representations jointly. We aim to improve on a previous mapping method [1] subject to errors due to interference, and which provides plate geometry estimates without uncertainty assessment. The grid can represent, all along the mapping process, both areas identified as inside or outside the current plate and areas whose state is still unknown, making it is suitable e.g. for detecting a change of plate, or for use in a later active-sensing strategy. We also leverage the resulting spatial information to filter out candidate plate edges that are no longer relevant, mitigating the detrimental effect of interference. We test the approach in simulation, with acoustic data acquired manually and with a real robot. Results show that it is effective for building combined map representations and robust to echo misdetection, contrary to a more standard mapping approach.
Published: 2021

21. Impact of non-axisymmetric magnetic field perturbations on flows

Author: Varennes, R, Garbet, X, Vermare, L, Sarazin, Y, Grandgirard, V, Dif-Pradalier, Guilhem, Peret, M, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Laboratoire de Physique des Plasmas (LPP), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), European Project: 633053,H2020,EURATOM-Adhoc-2014-20,EUROfusion(2014), icard, valerie, and Implementation of activities described in the Roadmap to Fusion during Horizon 2020 through a Joint programme of the members of the EUROfusion consortium - EUROfusion - - H20202014-01-01 - 2018-12-31 - 633053 - VALID
Subjects: [PHYS]Physics [physics], ComputingMilieux_MISCELLANEOUS, [PHYS] Physics [physics]
Abstract: International audience
Published: 2021

22. How to prepare the GYSELA-X code to future exascale edge-core simulations

Author: Grandgirard, Virginie, Asahi, Y, Bigot, J, Bourne, E, Dif-Pradalier, Guilhem, Donnel, P, Garbet, X, Ghendrih, Ph., Güçlü, Yaman, Kormann, K, Midou, D, Munschy, Y, Obrejan, K, Passeron, Ch, Varennes, R, Sarazin, Y, Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Japan Atomic Energy Agency, Maison de la Simulation (MDLS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut National de Recherche en Informatique et en Automatique (Inria)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Ecole Polytechnique Fédérale de Lausanne (EPFL), Max-Planck-Institut für Plasmaphysik [Garching] (IPP), Association for Computing Machinery (ACM), and the Swiss National Supercomputing Centre (CSCS)
Subjects: [PHYS]Physics [physics], ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2021

23. Machine learning techniques to characterize functional traits of plankton from image data

Author: Eric C. Orenstein, Sakina‐Dorothée Ayata, Frédéric Maps, Érica C. Becker, Fabio Benedetti, Tristan Biard, Thibault de Garidel‐Thoron, Jeffrey S. Ellen, Filippo Ferrario, Sarah L. C. Giering, Tamar Guy‐Haim, Laura Hoebeke, Morten Hvitfeldt Iversen, Thomas Kiørboe, Jean‐François Lalonde, Arancha Lana, Martin Laviale, Fabien Lombard, Tom Lorimer, Séverine Martini, Albin Meyer, Klas Ove Möller, Barbara Niehoff, Mark D. Ohman, Cédric Pradalier, Jean‐Baptiste Romagnan, Simon‐Martin Schröder, Virginie Sonnet, Heidi M. Sosik, Lars S. Stemmann, Michiel Stock, Tuba Terbiyik‐Kurt, Nerea Valcárcel‐Pérez, Laure Vilgrain, Guillaume Wacquet, Anya M. Waite, Jean‐Olivier Irisson, Laboratoire d'océanographie de Villefranche (LOV), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de la Mer de Villefranche (IMEV), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université Laval [Québec] (ULaval), Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD [France-Nord])-Université de Lille-Université du Littoral Côte d'Opale (ULCO)-Centre National de la Recherche Scientifique (CNRS), Universidade Federal de Santa Catarina = Federal University of Santa Catarina [Florianópolis] (UFSC), Institute of Biogeochemistry and Pollutant Dynamics [ETH Zürich] (IBP), Department of Environmental Systems Science [ETH Zürich] (D-USYS), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich)- Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), 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), Scripps Institution of Oceanography (SIO), University of California [San Diego] (UC San Diego), University of California-University of California, National Oceanography Centre [Southampton] (NOC), University of Southampton, Israel Oceanographic and Limnological Research - IOLR (ISRAEL), Universiteit Gent = Ghent University [Belgium] (UGENT), Alfred Wegener Institute for Polar and Marine Research (AWI), DTU Centre for Ocean Life, Technical University of Denmark [Lyngby] (DTU), Laboratoire de Vision et Systèmes Numériques (LVSN), Institut Mediterrani d'Estudis Avancats (IMEDEA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Universidad de las Islas Baleares (UIB), Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC), Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Terre et Environnement de Lorraine (OTELo), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Institut Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), Swiss Federal Insitute of Aquatic Science and Technology [Dübendorf] (EAWAG), Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Toulon (UTLN), Helmholtz-Zentrum Hereon, Georgia Tech Lorraine [Metz], Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Georgia Institute of Technology [Atlanta]-CentraleSupélec-Ecole Nationale Supérieure des Arts et Metiers Metz-Centre National de la Recherche Scientifique (CNRS), Écologie et Modèles pour l'Halieutique (EMH), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Kiel University, University of Rhode Island (URI), Woods Hole Oceanographic Institution (WHOI), Cukurova University, Centro Oceanografico de Malaga [Fuengirola, Spain] (COM), Instituto Español de Oceanografía. Málaga (Spain), Dalhousie University [Halifax], Centre National de la Recherche Scientifique (CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Institut national des sciences de l'Univers (INSU - CNRS), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Collège de France (CdF (institution))-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Écologie et Modèles pour l'Halieutique (IFREMER EMH), Institut Français de Recherche pour l'Exploitation de la Mer - Atlantique (IFREMER Atlantique), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Centre National de la Recherche Scientifique (France), Belmont Forum, Université Laval, Natural Sciences and Engineering Research Council of Canada, Research Foundation - Flanders, ETH Zürich, Gordon and Betty Moore Foundation, National Science Foundation (US), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Brasil), Agence Nationale de la Recherche (France), Ministerio de Economía y Competitividad (España), Institut Universitaire de France, Simons Foundation, Sorbonne Université, Processus et interactions de fine échelle océanique (PROTEO), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-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)-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)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), 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)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Nord]), Scripps Institution of Oceanography (SIO - UC San Diego), University of California (UC)-University of California (UC), Israel Oceanographic and Limnological Research (IOLR), Universiteit Gent = Ghent University (UGENT), Danmarks Tekniske Universitet = Technical University of Denmark (DTU), Ecole Nationale Supérieure des Arts et Metiers Metz-Georgia Institute of Technology [Atlanta]-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Dynamique et durabilité des écosystèmes : de la source à l’océan (DECOD), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Unité Halieutique Grand Ouest (HALGO), Instituto Español de Oceanografía (IEO), Málaga., ANR-19-CE01-0006,RhiCycle,Role des Rhizaria dans les cycles biogéochimiques de l'océan épi- et mésoplélagique(2019), ANR-18-BELM-0003,WWW.PIC,World Wide Web of Plankton Image Curation(2018), Laboratoire d'océanographie de Villefranche [LOV], Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 [LOG], Universidade Federal de Santa Catarina = Federal University of Santa Catarina [Florianópolis] [UFSC], Institute of Biogeochemistry and Pollutant Dynamics [ETH Zürich] [IBP], Centre européen de recherche et d'enseignement des géosciences de l'environnement [CEREGE], National Oceanography Centre [Southampton] [NOC], Universiteit Gent = Ghent University [UGENT], Alfred Wegener Institute for Polar and Marine Research [AWI], Laboratoire de Vision et Systèmes Numériques [LVSN], Institut Mediterrani d'Estudis Avancats [IMEDEA], Laboratoire Interdisciplinaire des Environnements Continentaux [LIEC], Institut Universitaire de France [IUF], Swiss Federal Insitute of Aquatic Science and Technology [Dübendorf] [EAWAG], Institut méditerranéen d'océanologie [MIO], Écologie et Modèles pour l'Halieutique [EMH], University of Rhode Island [URI], Woods Hole Oceanographic Institution [WHOI], and Institut Français de Recherche pour l'Exploitation de la Mer [IFREMER]
Subjects: [SDV.EE]Life Sciences [q-bio]/Ecology, environment, DIEL VERTICAL MIGRATION, CELL-VOLUME, Functional trait-based ecology, plankton, imaging, machine learning, PHOTOSYNTHETIC CHARACTERISTICS, Biology and Life Sciences, Aquatic Science, Oceanography, SIZE, Centro Oceanográfico de Málaga, PHYTOPLANKTON, LIFE-HISTORY TRAITS, FLUORESCENCE, Medio Marino, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, GONAD MORPHOLOGY, MARINE COPEPODS, PELAGIC COPEPODS, SDG 15 - Life on Land
Abstract: Plankton imaging systems supported by automated classification and analysis have improved ecologists' ability to observe aquatic ecosystems. Today, we are on the cusp of reliably tracking plankton populations with a suite of lab-based and in situ tools, collecting imaging data at unprecedentedly fine spatial and temporal scales. But these data have potential well beyond examining the abundances of different taxa; the individual images themselves contain a wealth of information on functional traits. Here, we outline traits that could be measured from image data, suggest machine learning and computer vision approaches to extract functional trait information from the images, and discuss promising avenues for novel studies. The approaches we discuss are data agnostic and are broadly applicable to imagery of other aquatic or terrestrial organisms., SDA acknowledges funding from CNRS for her sabbatical in 2018–2020. JOI acknowledges funding from the Belmont Forum, grant ANR-18-BELM-0003-01. This work is a contribution to the scientific program of Québec Océan and the Takuvik Joint International Laboratory (UMI3376; CNRS - Université Laval). FM was supported by an NSERC Discovery Grant (RGPIN-2014-05433). MS is supported by the Research Foundation - Flanders (FWO17/PDO/067). FB received support from ETH Zürich. MDO is supported by the Gordon and Betty Moore Foundation and the U.S. National Science Foundation. ECB is supported by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) under the grant agreement no. 88882.438735/2019-01. TB is supported by the French National Research Agency (ANR-19-CE01-0006). NVP is supported by the Spanish State Research Agency, Ministry of Science and Innovation (PTA2016-12822-I). FL is supported by the Institut Universitaire de France (IUF). HMS was supported by the Simons Foundation (561126) and the U.S. National Science Foundation (CCF-1539256, OCE-1655686). LS was supported by the Chair VISION from CNRS/Sorbonne Université.
Published: 2021

24. Learning the Propagation Properties of Plate-like Structures for Lamb Wave-based Mapping

Author: Ouabi, Othmane-Latif, POMAREDE, Pascal, Declercq, Nico, Zeghidour, Neil, Geist, Matthieu, Pradalier, Cédric, Georgia Tech Lorraine [Metz], Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Georgia Institute of Technology [Atlanta]-CentraleSupélec-Ecole Nationale Supérieure des Arts et Metiers Metz-Centre National de la Recherche Scientifique (CNRS), Georgia Institute of Technology [Atlanta], and Google Research [Paris]
Subjects: Lamb waves, Acoustic mapping, [INFO.INFO-RB]Computer Science [cs]/Robotics [cs.RO], Helmholtz equation, Model learning, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing, Optimal beamforming, [PHYS.MECA.ACOU]Physics [physics]/Mechanics [physics]/Acoustics [physics.class-ph]
Abstract: The inspection of sizeable plate-based metal structures such as storage tanks or marine vessel hulls is a significant stake in the industry, which necessitates reliable and time-efficient solutions. Although Lamb waves have been identified as a promising solution for long-range non-destructive testing, and despite the substantial progress made in autonomous navigation and environment sensing, a Lamb-wave-based robotic system for extensive structure monitoring is still lacking. Following previous work on ultrasonic Simultaneous Localization and Mapping (SLAM), we introduce a method to achieve plate geometry inference without prior knowledge of the material propagation properties, which may be lacking during a practical inspection task in challenging and outdoor environments. Our approach combines focalization to adjust the propagation model parameters and beamforming to infer the plate boundaries location by relying directly on acoustic measurements acquired along the mobile unit trajectory. For each candidate model, the focusing ability of the corresponding beamformer is assessed over high-pass filtered beamforming maps to further improve the robustness of the plate geometry estimates. We then recover the optimal space-domain beamformer through a simulated annealing optimization process. We evaluate our method on three sets of experimental data acquired in different conditions and show that accurate plate geometry inference can be achieved without any prior propagation model. Finally, the results show that the optimal beamformer outperforms the beamformer resulting from the predetermined propagation model in non-nominal acquisition conditions.
Published: 2021

25. Interplay between core, edge and scrape-off layer in turbulent magnetised plasmas: Lessons learnt from an information theoretic measure, the 'transfer entropy' to assess causality in nonlinear plasma dynamics

Author: Dif-Pradalier, G., Ph. Ghendrih, Sarazin, Y., Garbet, X., Grandgirard, V., Munschy, Y., Varennes, R., laure vermare, Camenen, Y., Widmer, F., Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Physique des interactions ioniques et moléculaires (PIIM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), European Project: 633053,H2020,EURATOM-Adhoc-2014-20,EUROfusion(2014), European Project: 824158,H2020-EU.1.4. - EXCELLENT SCIENCE - Research Infrastructures ,EoCoE-II(2019), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU), and European Project: 824158,EoCoE-II
Subjects: [PHYS]Physics [physics], [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph]
Abstract: International audience; The present manuscript is meant to provide a companion pedagogical approach to an information theoretic measure, the "Transfer Entropy" method, useful to assess causality in complex (time series) datasets. This manuscript describes useful basics for the forthcoming discussion on the causal chain of events that leads to the onset of a spontaneous and stable edge transport barrier in flux-driven gyrokinetics when core, edge and scrape-off layer regions self-consistently interplay.
Published: 2021

26. Wave trapping and E × B staircases

Author: Philippe Ghendrih, Yanick Sarazin, G. Dif-Pradalier, C. Gillot, Laure Vermare, Xavier Garbet, V. Grandgirard, R Varennes, O Panico, Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), École normale supérieure de Lyon (ENS de Lyon), Laboratoire de Physique des Plasmas (LPP), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), National Science Foundation under Grant No. NSF PHY-1748958, and École normale supérieure - Lyon (ENS Lyon)
Subjects: Physics, Wave packet, Mechanics, Condensed Matter Physics, 01 natural sciences, Instability, [PHYS.PHYS.PHYS-GEN-PH]Physics [physics]/Physics [physics]/General Physics [physics.gen-ph], 010305 fluids & plasmas, Shear (sheet metal), Amplitude, 0103 physical sciences, Zonal flow, Refraction (sound), Wavenumber, 010306 general physics, Shear flow
Abstract: International audience; A model of E×B staircases is proposed, based on a wave kinetic equation coupled to a poloidal momentum equation. A staircase pattern is idealised as a periodic radial structure of zonal shear layers that bound regions of propagating wave packets, viewed as avalanches. Wave packets are trapped in shear flow layers due to refraction. In this model an E × B staircase motif emerges due to the interaction between propagating wave packets (avalanches) and trapped waves in presence of an instability drive. Amplitude, shape, and spatial period of the staircase E × B flow are predicted as functions of the background fluctuation spectrum and the growth rate of drift waves. The zonal flow velocity radial profile is found to peak near its maxima and to flatten near its minima. The optimum configuration for staircase formation is a growth rate that is maximum at zero radial wave number. A mean shear flow is responsible for a preferential propagation speed of avalanches. It is not a mandatory condition for the existence of staircase solutions, but has an impact on their spatial period.
Published: 2021

27. Evaluation of prioritized deep system identification on a path following task

Author: Antoine Mahe, Antoine Richard, Matthieu Geist, Stéphanie Aravecchia, Cédric Pradalier, Georgia Tech Lorraine [Metz], Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Georgia Institute of Technology [Atlanta]-CentraleSupélec-Ecole Nationale Supérieure des Arts et Metiers Metz-Centre National de la Recherche Scientifique (CNRS), and Google Research [Paris]
Subjects: 0209 industrial biotechnology, business.industry, Computer science, Mechanical Engineering, Control (management), System identification, 02 engineering and technology, Systems modeling, Machine learning, computer.software_genre, Industrial and Manufacturing Engineering, Task (project management), Identification (information), 020901 industrial engineering & automation, Artificial Intelligence, Control and Systems Engineering, Control theory, [INFO.INFO-RB]Computer Science [cs]/Robotics [cs.RO], Artificial intelligence, Electrical and Electronic Engineering, business, Baseline (configuration management), computer, Software, Importance sampling
Abstract: This paper revisits system identification and shows how new paradigms from machine learning can be used to improve it in the case of non-linear systems modeling from noisy and unbalanced dataset. We show that using importance sampling schemes in system identification can provide a significant performance boost in modeling, which is helpful to a predictive controller. The performance of the approach is first evaluated on simulated data of a Unmanned Surface Vehicle (USV). Our approach consistently outperforms baseline approaches on this dataset. Moreover we demonstrate the benefits of this identification methodology in a control setting. We use the model of the Unmanned Surface Vehicle (USV) in a Model Predictive Path Integral (MPPI) controller to perform a track following task. We discuss the influence of the controller parameters and show that the prioritized model outperform standard methods. Finally, we apply the Model Predictive Path Integral (MPPI) on a real system using the know-how developed here.
Published: 2021

28. Zonal instability and wave trapping

Author: David Zarzoso, O Panico, G. Dif-Pradalier, Yanick Sarazin, C. Gillot, Xavier Garbet, E Bourne, V. Grandgirard, Laure Vermare, Philippe Ghendrih, R Varennes, Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), École normale supérieure de Lyon (ENS de Lyon), Physique des interactions ioniques et moléculaires (PIIM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique des Plasmas (LPP), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Garbet, Xavier, and École normale supérieure - Lyon (ENS Lyon)
Subjects: Physics, History, Zonal flow (plasma), Trapping, Mechanics, 01 natural sciences, Power law, Instability, 010305 fluids & plasmas, Computer Science Applications, Education, Collision operator, Flow (mathematics), Physics::Plasma Physics, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], [PHYS.PHYS.PHYS-PLASM-PH] Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], 0103 physical sciences, Physics::Space Physics, Diffusion (business), 010306 general physics, Sign (mathematics)
Abstract: This paper presents a model for zonal flow generation based on a wave kinetic equation coupled to a poloidal momentum equation in a regime where wave trapping matters. Several models of the wave collision operator have been tested: Krook, diffusion and diffusion plus an instability growth rate. Conditions for zonal instability have been identified. It is found that a zonal instability is possible in all cases. However the force is a power law of the zonal velocity, so different from the quasi-linear case of random phases that produces a force that is linear in velocity. Also the zonal force may change sign, leading to flow radial profiles that are not sinusoidal.
Published: 2021

29. Model order reduction approach to one-dimensional collisionless closure problem

Author: Gillot, Camille, Dif-Pradalier, Guilhem, Garbet, Xavier, Ghendrih, Philippe, Grandgirard, Virginie, Sarazin, Yanick, CEA Cadarache, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), and Sarazin, Yanick
Subjects: [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], [PHYS.PHYS.PHYS-PLASM-PH] Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph]
Published: 2021

30. Key role of phase dynamics & diamagnetic drive on Reynolds stress in fusion plasma turbulence

Author: Sarazin, Y., Dif-Pradalier, Guilhem, Ghendrih, Ph., Garbet, X., Berger, A., Bigué, R., Bourne, Emilie, Grandgirard, Virginie, Obrejan, Kevin, Varennes, R., Vermare, L., icard, valerie, Implementation of activities described in the Roadmap to Fusion during Horizon 2020 through a Joint programme of the members of the EUROfusion consortium - EUROfusion - - H20202014-01-01 - 2018-12-31 - 633053 - VALID, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Laboratoire de Physique des Plasmas (LPP), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and European Project: 633053,H2020,EURATOM-Adhoc-2014-20,EUROfusion(2014)
Subjects: [PHYS]Physics [physics], [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], [PHYS.PHYS.PHYS-PLASM-PH] Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], ComputingMilieux_MISCELLANEOUS, [PHYS] Physics [physics]
Abstract: International audience
Published: 2021

31. A sensor fusion framework for wearable sensor suites

Author: Chahine, Georges, Vaidis, Maxime, Pomerleau, François, Pradalier, Cédric, UMI GT CNRS, Georgia Institute of Technology [Atlanta]-Centre National de la Recherche Scientifique (CNRS), Georgia Institute of Technology [Atlanta], and Georgia Institute of Technology [Lorraine, France]
Subjects: [SPI]Engineering Sciences [physics], ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION
Abstract: International audience; We present a generalized mapping framework that can withstand the challenges incurred by working in unstructured outdoor environments, such as a snowy forest. The proposed method takes advantage of a sensor fusion scheme, where sensors such as cameras and lidars are used in order to reconstruct the surrounding natural environment. Although mapping techniques such as SLAM and ICP cannot themselves properly handle the complexity of natural scenes, they do have the potential to contribute to the global solution in a proposed sensor fusion scheme, based on a factor graph architecture. In this paper, we propose an innovative map registration scheme for visual maps, and show how it can improve the reconstruction quality after data fusion. We also analyze the behavior and sensitivity of factor graphs to uncertainties, by comparing the residual error with different parameter combinations such as variances, using an exhaustive grid search with ground truth comparison. Finally, we suggest an ICP-inferred loop closure, capable of compensating position and attitude drift. The experiments are carried out by recording in a snowy forest using a wearable sensor suite. In the experiments, ground truth was acquired using a millimeter-accurate total station. The proposed framework is shown to be robust and likewise capable of providing estimates that are otherwise unattainable using classic techniques, such as visual SLAM and ICP for lasers. Finally, a visible improvement in the map reconstruction quality is shown, and the proposed framework achieves a translation error of 0.36 meters.
Published: 2021

32. Formation of the radial electric field profile in WEST tokamak

Author: Vermare, Laure, Dif-Pradalier, Guilhem, Hennequin, Pascale, Gunn, James, Garbet, Xavier, Artaud, Jean-Francois, Gurcan, Ozgur, Bourdelle, Clarisse, Clairet, Frédéric, Fedorczak, Nicolas, Honoré, Cyrille, Morales, Jorge, Sarazin, Yanick, Grandgirard, Virginie, Varennes, Robin, Vezinet, Didier, Peret, Mathieu, Dumont, Rémi, Goniche, Marc, Maget, Patrick, icard, valerie, Implementation of activities described in the Roadmap to Fusion during Horizon 2020 through a Joint programme of the members of the EUROfusion consortium - EUROfusion - - H20202014-01-01 - 2018-12-31 - 633053 - VALID, Laboratoire de Physique des Plasmas (LPP), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), The WEST Team, and European Project: 633053,H2020,EURATOM-Adhoc-2014-20,EUROfusion(2014)
Subjects: [PHYS]Physics [physics], [PHYS] Physics [physics]
Abstract: International audience; The shear of the radial electric field at the edge is widely accepted to be responsible for turbulence reductionin edge transport barriers and thought as a key ingredient of the improved confinement of H-mode plasmas.Nevertheless, a full understanding of how its profile builds up at the edge is still lacking. It can either beformulated as the result of a competition between several mechanisms that generate and damp flows or as theresult of a non-ambipolar particle flux, which enhances radial charge separation imposing a radial electric fieldprofile. Among possible mechanisms, one can think of turbulence generated flow via Reynolds stress, ion orbitlosses, toroidal magnetic ripple and the effect of neutral friction at the edge. Based on previous results obtainedon Tore Supra, the radial profile of the perpendicular flow expected in WEST can be separated in three spatialareas. Inside ρ = 0.8, the radial electric field is dominated by losses of thermal ions in the magnetic ripple while between 0.7 < ρ < 0.95, a competition between this latter and the generation of large scale flows byturbulence appears as a possible explanation of the measured poloidal asymmetry of the mean perpendicularvelocity. In addition, edge conditions such as contact points and parallel dynamics in the scrape-off-layer(SOL) influence the edge profiles beyond ρ = 0.9 (3). This contribution presents unexpected differences in theradial electric field profile observed in WEST between Lower Single Null (LSN) and Upper Single Null (USN)configurations and a study of the competition between specific mechanisms playing a role in the formationof this profile.
Published: 2021

33. Interplay between core, edge and scrape-off layer in turbulent magnetised plasmas

Author: Dif-Pradalier, Guilhem, Ghendrih, Ph., Sarazin, Y., Garbet, X., Grandgirard, V, Munschy, Y., Varennes, R., Vermare, L., Camenen, Y., Widmer, F., icard, valerie, Implementation of activities described in the Roadmap to Fusion during Horizon 2020 through a Joint programme of the members of the EUROfusion consortium - EUROfusion - - H20202014-01-01 - 2018-12-31 - 633053 - VALID, and Energy Oriented Center of Excellence : toward exascale for energy - EoCoE-II - - H2020-EU.1.4. - EXCELLENT SCIENCE - Research Infrastructures 2019-01-01 - 2022-06-30 - 824158 - VALID
Subjects: [PHYS.PHYS.PHYS-PLASM-PH] Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], [PHYS] Physics [physics]
Abstract: The present manuscript is meant to provide a companion pedagogical approach to an information theoretic measure, the "Transfer Entropy" method, useful to assess causality in complex (time series) datasets. This manuscript describes useful basics for the forthcoming discussion on the causal chain of events that leads to the onset of a spontaneous and stable edge transport barrier in flux-driven gyrokinetics when core, edge and scrape-off layer regions self-consistently interplay.
Published: 2021

34. Towards an automatic detection of charcoal production platforms in airborne LiDAR images

Author: Oliveira, Cláudia, Aravecchia, Stéphanie, May, L., Pradalier, Cedric, Robin, Vincent, Devin, Simon, Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC), Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Terre et Environnement de Lorraine (OTELo), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Georgia Tech Lorraine [Metz], Ecole Nationale Supérieure des Arts et Metiers Metz-Georgia Institute of Technology [Atlanta]-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Georgia Institute of Technology [Atlanta], and OLIVEIRA, Cláudia
Subjects: [SDE.BE] Environmental Sciences/Biodiversity and Ecology, [INFO.INFO-LG]Computer Science [cs]/Machine Learning [cs.LG], [SHS.ENVIR] Humanities and Social Sciences/Environmental studies, [SHS.ENVIR]Humanities and Social Sciences/Environmental studies, [INFO.INFO-LG] Computer Science [cs]/Machine Learning [cs.LG], [SDE.BE]Environmental Sciences/Biodiversity and Ecology, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2020

35. A Comprehensive Benchmark of Neural Networks for System Identification

Author: Richard, Antoine, Mahé, Antoine, Pradalier, Cedric, Rozenstein, Offer, Geist, Matthieu, Georgia Tech Lorraine [Metz], Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Georgia Institute of Technology [Atlanta]-CentraleSupélec-Ecole Nationale Supérieure des Arts et Metiers Metz-Centre National de la Recherche Scientifique (CNRS), Laboratoire Lorrain de Recherche en Informatique et ses Applications (LORIA), Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Machine Learning and Computational Biology (ABC), Department of Algorithms, Computation, Image and Geometry (LORIA - ALGO), Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire Lorrain de Recherche en Informatique et ses Applications (LORIA), Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Pradalier, Cedric, Ecole Nationale Supérieure des Arts et Metiers Metz-Georgia Institute of Technology [Atlanta]-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), and Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)
Subjects: [INFO.INFO-AI] Computer Science [cs]/Artificial Intelligence [cs.AI], [INFO.INFO-RB] Computer Science [cs]/Robotics [cs.RO], [INFO.INFO-RB]Computer Science [cs]/Robotics [cs.RO], [INFO.INFO-AI]Computer Science [cs]/Artificial Intelligence [cs.AI]
Abstract: This paper compares a wide variety of neural network architectures applied in the context of black-box modeling for robotics and control. We compare six different architectural concepts and four activation functions, with over three hundred different models. Those models were applied to three robotics datasets to show the differences in performance between the architectures along with their limitations.
Published: 2019

36. Smooth Local Planning Incorporating Steering Constraints

Author: Cédric Pradalier, Wolfram Burgard, Freya Fleckenstein, Christian Dornhege, Wera Winterhalter, Department of Computer Science [Freiburg], University of Freiburg [Freiburg], Georgia Tech Lorraine [Metz], Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Georgia Institute of Technology [Atlanta]-CentraleSupélec-Ecole Nationale Supérieure des Arts et Metiers Metz-Centre National de la Recherche Scientifique (CNRS), and Pradalier, Cedric
Subjects: 0106 biological sciences, Flexibility (engineering), 0209 industrial biotechnology, Computer science, [INFO.INFO-RB] Computer Science [cs]/Robotics [cs.RO], Context (language use), 02 engineering and technology, 01 natural sciences, Motion (physics), 020901 industrial engineering & automation, Control theory, 11. Sustainability, Path (graph theory), Local planning, Key (cryptography), Robot, [INFO.INFO-RB]Computer Science [cs]/Robotics [cs.RO], Instant centre of rotation, 010606 plant biology & botany
Abstract: Individually controllable and steerable wheels provide vehicles with greater flexibility and efficiency. A key challenge in the context of such vehicles lies in the effective planning of the motion commands in order to properly deal with the potentially large required changes in the steering angles and to properly incorporate the given motion constraints. Especially large vehicles often perform large steering angle changes only while standing to prevent physical damage to the robot. In this paper, we introduce a novel planner for vehicles with individually controllable and steerable wheels and two novel methods to incorporate steering constraints. The latter are designed to provide smooth changes of the instantaneous center of rotation (ICR). Extensive experiments in simulation and on the real robot reveal that our methods allow for an effective planning of steering commands, reduce the travel time by decreasing the time spent standing for wheel reconfigurations, and additionally enable the vehicle to accurately follow a given path.
Published: 2019

37. Laser-Supported Monocular Visual Tracking for Natural Environments

Author: Georges Chahine, Cédric Pradalier, Pradalier, Cedric, Georgia Tech Lorraine [Metz], Université de Franche-Comté (UFC), and Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Georgia Institute of Technology [Atlanta]-CentraleSupélec-Ecole Nationale Supérieure des Arts et Metiers Metz-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0209 industrial biotechnology, Monocular, Computer science, business.industry, Reliability (computer networking), [INFO.INFO-RB] Computer Science [cs]/Robotics [cs.RO], [INFO.INFO-CV]Computer Science [cs]/Computer Vision and Pattern Recognition [cs.CV], Scale (descriptive set theory), 02 engineering and technology, Laser, Natural (archaeology), law.invention, Constraint (information theory), 020901 industrial engineering & automation, [INFO.INFO-CV] Computer Science [cs]/Computer Vision and Pattern Recognition [cs.CV], law, 0202 electrical engineering, electronic engineering, information engineering, [INFO.INFO-RB]Computer Science [cs]/Robotics [cs.RO], Eye tracking, 020201 artificial intelligence & image processing, Computer vision, Artificial intelligence, Set (psychology), business
Abstract: This paper presents and demonstrates a 2D laser-supported visual tracking solution, that can achieve reliable performance in unstructured scenes such as those seen in natural environment surveys. The method is shown to sufficiently stabilize scale and account for scale drift, as well as improve overall reliability. The suggested method is minimally invasive, does not require any additional parameter and does not necessarily require a laser, which can be replaced by any set of points with known depth, with no constraint on the temporal continuity of known points. We also test our method on 4 surveys, captured in a natural riverine environment, that proved to be challenging even for the state-of-the-art in visual tracking.
Published: 2019

38. IMPACT OF A RIPPLED MAGNETIC FIELD ON FLOWS

Author: Varennes, R., laure vermare, Garbet, X., Sarazin, Y., Dif- Pradalier, G., Grandgirard, V., Zarzoso, D., Peret, M., Bourne, E., Faganello, M., Dumont, R., Obrejan, K., Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Institut de Recherche sur la Fusion par confinement Magnétique (IRFM)
Subjects: [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2020

39. Transport in Fusion Plasmas: Is the Tail Wagging the Dog?

Author: Guilhem Dif-Pradalier, Ph. Ghendrih, Sarazin, Y., Widmer, F., Camenen, Y., Garbet, X., Gillot, C., Grandgirard, V., laure vermare, icard, valerie, Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Aix Marseille Université (AMU), Laboratoire de Physique des Plasmas (LPP), Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
Subjects: [PHYS]Physics [physics], [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], [PHYS.PHYS.PHYS-PLASM-PH] Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], ComputingMilieux_MISCELLANEOUS, [PHYS] Physics [physics]
Abstract: International audience
Published: 2020

40. Utilisation d’images microscopiques artificielles en complément d’images réelles pour la détection automatique de diatomées par apprentissage profond

Author: Faure-Giovagnoli, Pierre, Venkataramanan, Aishwarya, Heudre, David, DE GARIDEL-THORON, Thibault, Usseglio-Polatera, Philippe, Pradalier, Cedric, Laviale, Martin, Laviale, Martin, Georgia Institute of Technology [Lorraine, France], Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC), Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Terre et Environnement de Lorraine (OTELo), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Zone Atelier du Bassin de la Moselle [LTSER France] (ZAM), Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Direction Régionale de l'Environnement, de l'Aménagement et du Logement - Grand Est (DREAL Grand Est), 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), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Terre et Environnement de Lorraine (OTELo), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Institut Ecologie et Environnement (INEE), and Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [SDE.BE] Environmental Sciences/Biodiversity and Ecology, MESH: qualité de l’eau, bioindication, diatomées, analyse d’images, reconnaissance automatique, apprentissage machine, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, [SDV.EE.ECO] Life Sciences [q-bio]/Ecology, environment/Ecosystems, [SDE.BE]Environmental Sciences/Biodiversity and Ecology
Abstract: International audience; Les diatomées sont des microalgues présentes dans tous les milieux aquatiques. Ces organismes sont utilisés en routine comme bioindicateur de la qualité écologique des eaux douces dans le cadre de la mise en œuvre de la Directive Cadre européenne sur l'Eau (DCE). Les indices biologiques actuels basés sur les diatomées reposent sur des critères morphologiques (forme et ornementation de l’exosquellette siliceux, le frustule) pas toujours faciles à caractériser en routine (i.e. à l’aide de méthodes optiques conventionnelles). L’identification est donc chronophage, souvent sujette à de multiples biais (expérience de l'opérateur, qualité de l'image) et nécessite un niveau élevé d’expertise.Ceci justifie le développement d'un outil plus robuste, basé sur une classification automatique des diatomées. Cet objectif est toujours un défi d’actualité, depuis les premières tentatives datant des années 90. Dans ce contexte, le développement récent des approches d’apprentissage profond pour identifier et quantifier les traits des organismes à partir d’images semble prometteur pour résoudre les problèmes rencontrés jusqu’à présent. Notre objectif est donc de proposer un nouvel outil d’identification des diatomées basé sur des algorithmes de reconnaissance automatique de formes à partir d’images individuelles. Par rapport à l’approche classique d’identification des diatomées, cet outil se veut notamment plus robuste car indépendant de l’opérateur et permettra d’améliorer (gain de temps, coût) ceux actuellement disponibles dans le cadre du suivi réglementaire de l’état écologique des cours d’eau.Le développement de cet outil implique 1/l’acquisition d’une base de données représentative du milieu naturel (banques d’images de diatomées) qui permette 2) le développement des algorithmes d’identification des diatomées. En première approche, une banque simplifiée d’images représentatives de 209 espèces de diatomées (environ 9 000 images au total) a été créée à partir de guides d’identification en libre accès. Cette base d’images a permis de générer environ 30 000 images composites simulant des images d’échantillons naturels. Ceci a permis le développement de premiers algorithmes de détection (diatomées vs. débris) et de classification (espèces présentes). Les premiers résultats obtenus montrent que l’outil de reconnaissance permet de distinguer les diatomées présentes sur un échantillon (précision de 90%) ainsi que les débris (précision de 99%). L’outil a également été testé sur quelques images réelles avec une précision pouvant atteindre 86% pour les débris et 73% pour les diatomées présentes. Ces résultats encourageants démontrent la faisabilité de notre approche (preuve de concept). La banque d’images sera donc consolidée afin de la rendre plus représentative de l’ensemble des espèces indicatrices de diatomées retrouvées dans une zone géographique donnée (e.g. bassin de la Moselle, bassin Rhin-Meuse) et ainsi d’améliorer la performance des algorithmes de reconnaissance.
Published: 2020

41. Classification automatique des diatomées par apprentissage profond pour l’amélioration du diagnostic écologique des milieux aquatiques

Author: Faure-Giovagnoli, Pierre, Venkataramanan, Aishwarya, Figus, Cécile, Heudre, David, DE GARIDEL-THORON, Thibault, Noûs, Camille, Usseglio-Polatera, Philippe, Pradalier, C., Laviale, Martin, Laviale, Martin, Lorraine Artificicial Intelligence - - LOR-AI2020 - ANR-20-THIA-0010 - PNIA - VALID, Georgia Tech Lorraine [Metz], Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Georgia Institute of Technology [Atlanta]-CentraleSupélec-Ecole Nationale Supérieure des Arts et Metiers Metz-Centre National de la Recherche Scientifique (CNRS), Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Terre et Environnement de Lorraine (OTELo), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Zone Atelier du Bassin de la Moselle [LTSER France] (ZAM), Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Direction Régionale de l'Environnement, de l'Aménagement et du Logement - Grand Est (DREAL Grand Est), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Collège de France (CdF (institution))-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Laboratoire Cogitamus, ANR-20-THIA-0010,LOR-AI,Lorraine Artificicial Intelligence(2020), Ecole Nationale Supérieure des Arts et Metiers Metz-Georgia Institute of Technology [Atlanta]-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Terre et Environnement de Lorraine (OTELo), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), and 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)
Subjects: [SDE.BE] Environmental Sciences/Biodiversity and Ecology, qualité de l’eau, diatomées, analyse d’images, apprentissage machine, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, bioindication, reconnaissance automatique
Abstract: National audience; Les diatomées sont des microalgues présentes dans tous les milieux aquatiques. Ces organismes sont utilisés en routine comme bioindicateur de la qualité écologique des eaux douces dans le cadre de la mise en œuvre de la Directive Cadre européenne sur l'Eau (DCE). Les indices biologiques actuels basés sur les diatomées reposent sur des critères morphologiques (forme et ornementation de l’exosquellette siliceux, le frustule) pas toujours faciles à caractériser en routine (i.e. à l’aide de méthodes optiques conventionnelles). L’identification est donc chronophage, souvent sujette à de multiples biais (expérience de l'opérateur, qualité de l'image) et nécessite un niveau élevé d’expertise.Ceci justifie le développement d'un outil plus robuste, basé sur une classification automatique des diatomées. Cet objectif est toujours un défi d’actualité, depuis les premières tentatives datant des années 90. Dans ce contexte, le développement récent des approches d’apprentissage profond pour identifier et quantifier les traits des organismes à partir d’images semble prometteur pour résoudre les problèmes rencontrés jusqu’à présent. Notre objectif est donc de proposer un nouvel outil d’identification des diatomées basé sur des algorithmes de reconnaissance automatique de formes à partir d’images individuelles. Par rapport à l’approche classique d’identification des diatomées, cet outil se veut notamment plus robuste car indépendant de l’opérateur et permettra d’améliorer (gain de temps, coût) ceux actuellement disponibles dans le cadre du suivi réglementaire de l’état écologique des cours d’eau.Le développement de cet outil implique 1/l’acquisition d’une base de données représentative du milieu naturel (banques d’images de diatomées) qui permette 2) le développement des algorithmes d’identification des diatomées. En première approche, une banque simplifiée d’images représentatives de 209 espèces de diatomées (environ 9 000 images au total) a été créée à partir de guides d’identification en libre accès. Cette base d’images a permis de générer environ 30 000 images composites simulant des images d’échantillons naturels. Ceci a permis le développement de premiers algorithmes de détection (diatomées vs. débris) et de classification (espèces présentes). Les premiers résultats obtenus montrent que l’outil de reconnaissance permet de distinguer les diatomées présentes sur un échantillon (précision de 90%) ainsi que les débris (précision de 99%). L’outil a également été testé sur quelques images réelles avec une précision pouvant atteindre 86% pour les débris et 73% pour les diatomées présentes. Ces résultats encourageants démontrent la faisabilité de notre approche (preuve de concept). La banque d’images sera donc consolidée afin de la rendre plus représentative de l’ensemble des espèces indicatrices de diatomées retrouvées dans une zone géographique donnée (e.g. bassin de la Moselle, bassin Rhin-Meuse) et ainsi d’améliorer la performance des algorithmes de reconnaissance.
Published: 2020

42. Deep Representation Learning for Domain Adaptation of Semantic Image Segmentation

Author: Benbihi, Assia, Pradalier, Cedric, Geist, M., Georgia Tech Lorraine [Metz], Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Georgia Institute of Technology [Atlanta]-CentraleSupélec-Ecole Nationale Supérieure des Arts et Metiers Metz-Centre National de la Recherche Scientifique (CNRS), and DASTILLUNG, NADEGE
Subjects: [SPI.AUTO] Engineering Sciences [physics]/Automatic, ComputingMilieux_MISCELLANEOUS, [SPI.AUTO]Engineering Sciences [physics]/Automatic
Abstract: International audience
Published: 2019

43. Design and Implementation of Computer Vision based In-Row Weeding System

Author: Xiaolong Wu, Cédric Pradalier, Stéphanie Aravecchia, Georgia Tech Lorraine [Metz], Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Georgia Institute of Technology [Atlanta]-CentraleSupélec-Ecole Nationale Supérieure des Arts et Metiers Metz-Centre National de la Recherche Scientifique (CNRS), and Pradalier, Cedric
Subjects: 0209 industrial biotechnology, Dependency (UML), Computer science, Control (management), Environmental pollution, 02 engineering and technology, 020901 industrial engineering & automation, 0202 electrical engineering, electronic engineering, information engineering, [INFO.INFO-RB]Computer Science [cs]/Robotics [cs.RO], Computer vision, [INFO]Computer Science [cs], Delays, 2. Zero hunger, Control systems, business.industry, Deep learning, Tracking, [INFO.INFO-RB] Computer Science [cs]/Robotics [cs.RO], Agriculture, 15. Life on land, Pesticide, Cameras, Three-dimensional displays, 020201 artificial intelligence & image processing, Precision agriculture, Artificial intelligence, Weed, business, Robots
Abstract: International audience; Autonomous robotic weeding systems in precision farming have demonstrated their full potential to alleviate the current dependency on herbicides or pesticides by introducing selective spraying or mechanical weed removal modules, thus reducing the environmental pollution and improving the sustainability. However, most previous works require fast weed detection system to achieve real-time treatment. In this paper, a novel computer vision based weeding control system is presented, where a non-overlapping multi-camera system is introduced to compensate the indeterminate classification delays, thus allowing for more complicated and advanced detection algorithms, e.g. deep learning based methods. The suitable tracking and control strategies are developed to achieve accurate and robust in-row weed treatment, and the performance of the proposed system is evaluated in different terrain conditions in the presence of various delays.
Published: 2018

44. Illumination Robust Monocular Direct Visual Odometry for Outdoor Environment Mapping

Author: Cédric Pradalier, Xiaolong Wu, Pradalier, Cedric, Georgia Tech Lorraine [Metz], Université de Franche-Comté (UFC), and Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Georgia Institute of Technology [Atlanta]-CentraleSupélec-Ecole Nationale Supérieure des Arts et Metiers Metz-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0209 industrial biotechnology, Monocular, business.industry, Computer science, [INFO.INFO-RB] Computer Science [cs]/Robotics [cs.RO], ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, Initialization, [INFO.INFO-CV]Computer Science [cs]/Computer Vision and Pattern Recognition [cs.CV], 02 engineering and technology, Simultaneous localization and mapping, 020901 industrial engineering & automation, [INFO.INFO-CV] Computer Science [cs]/Computer Vision and Pattern Recognition [cs.CV], Robustness (computer science), Motion estimation, 0202 electrical engineering, electronic engineering, information engineering, RGB color model, [INFO.INFO-RB]Computer Science [cs]/Robotics [cs.RO], 020201 artificial intelligence & image processing, Computer vision, Artificial intelligence, Visual odometry, business, Reflection mapping, ComputingMethodologies_COMPUTERGRAPHICS
Abstract: Vision-based localization and mapping in outdoor environments is still a challenging issue, which requests significant robustness against various unpredictable illumination changes. In this paper, an illumination-robust direct monocular SLAM system that focuses on modeling outdoor scenery is presented. To deal with global and local lighting changes, such as solar flares, the state-of-art illumination invariant photometric costs for RGB-D and stereo SLAM systems are revisited in the context of their monocular counterpart, where the camera motion and scene structure are jointly optimized with a reasonably poor initialization. Based on our analysis, a combined cost is proposed to achieve a high-precision motion estimation with an improved convergence radius. The proposed system is extensively evaluated on the synthetic and real-world datasets regarding accuracy, robustness, and processing time, where our approach outperforms systems with other costs and state-of-art DSO and ORBSLAM2 systems.
Published: 2018

45. How to resort to apprenticeship in Italy ? A review of recent reforms and how it has been adopted by the actors

Author: Dif-Pradalier, Maël, Zarka, Samuel, Haute Ecole Spécialisée de Suisse Occidentale (HES-SO), Laboratoire interdisciplinaire pour la sociologie économique (LISE), Centre National de la Recherche Scientifique (CNRS)-Conservatoire National des Arts et Métiers [CNAM] (CNAM), and HESAM Université (HESAM)-HESAM Université (HESAM)
Subjects: Italie, [SHS.SOCIO]Humanities and Social Sciences/Sociology, Stage de formation, Disparité régionale, Apprentissage, Législation de l'apprentissage, [SHS]Humanities and Social Sciences
Abstract: International audience; Le manque d’engagement des entreprises italiennes dans l’apprentissage est fréquemment corrélé au coût du dispositif, comparativement à d’autres formules contractuelles. Toutefois, ce résultat interroge : si la concurrence entre contrats est si vive, comment saisir le recours à l’apprentissage lorsqu’il a lieu ? Pour répondre à cette question, l’article part de textes règlementaires et de statistiques touchant le fait apprenti en Italie, qui seront mis en regard d’un matériau d’entretiens auprès d’acteurs de l’apprentissage (responsables régionaux, employeurs et apprentis). Cette démarche permet de réveler plusieurs types d’encastrement au sein desquels le contrat d’apprentissage peut prendre sens : les compromis d’une entreprise familiale du nord du pays ou la perspective d’émigration d’un jeune diplômé d’un institut technique. De ce fait, cet article nous renseigne sur les conditions de primo-engagement en Italie.
Published: 2019

46. ELF : Embedded Localisation of Features in pre-trained CNN

Author: Matthieu Geist, Cédric Pradalier, Assia Benbihi, Georgia Tech Lorraine [Metz], Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Georgia Institute of Technology [Atlanta]-CentraleSupélec-Ecole Nationale Supérieure des Arts et Metiers Metz-Centre National de la Recherche Scientifique (CNRS), and DASTILLUNG, NADEGE
Subjects: FOS: Computer and information sciences, business.industry, Computer science, Computer Vision and Pattern Recognition (cs.CV), Detector, Computer Science - Computer Vision and Pattern Recognition, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, Pattern recognition, 02 engineering and technology, 010501 environmental sciences, 01 natural sciences, [SPI.AUTO]Engineering Sciences [physics]/Automatic, Maxima and minima, [SPI.AUTO] Engineering Sciences [physics]/Automatic, Robustness (computer science), 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, Saliency map, Artificial intelligence, business, Feature detection, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: This paper introduces a novel feature detector based only on information embedded inside a CNN trained on standard tasks (e.g. classification). While previous works already show that the features of a trained CNN are suitable descriptors, we show here how to extract the feature locations from the network to build a detector. This information is computed from the gradient of the feature map with respect to the input image. This provides a saliency map with local maxima on relevant keypoint locations. Contrary to recent CNN-based detectors, this method requires neither supervised training nor finetuning. We evaluate how repeatable and how ‘matchable’ the detected keypoints are with the repeatability and matching scores. Matchability is measured with a simple descriptor introduced for the sake of the evaluation. This novel detector reaches similar performances on the standard evaluation HPatches dataset, as well as comparable robustness against illumination and viewpoint changes on Webcam and photo-tourism images. These results show that a CNN trained on a standard task embeds feature location information that is as relevant as when the CNN is specifically trained for feature detection.
Published: 2019

47. Questioning the quasilinear nature of turbulent transport by means of gyrokinetic flux-driven nonlinear simulations

Author: Gillot, C., Dif-Pradalier, G., Sarazin, Y., Caschera, E., Ghendrih, Ph, Garbet, X., Grandgirard, V., Latu, G., Passeron, C., Bourdelle, C., Zarzoso, D., Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Physique des interactions ioniques et moléculaires (PIIM), and Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [PHYS]Physics [physics], Physics::Plasma Physics
Abstract: International audience; Efficiently operating a nuclear fusion device requires understanding and predicting turbulent transport processes. Reduced quasilinear models, backed on gyrokinetic gradient-driven nonlinear simulations, reveal extremely powerful in recovering experimentally measured steady state fluxes at low cost. However, flux-driven nonlinear simulations as well as experimental measurements reveal new features, such as transient and non-local dynamics like avalanches and turbulence self-organization close to marginal stability. We perform gyrokinetic simulations with GYSELA code [1] and focus on the impact of such forcing on turbulence properties. In particular, we study numerically the effect on stationary zonal flow on turbulent structures, and access the quasilinear nature of fluctuations. The angular rotation of electric potential structures is computed as the best-fitting non-linear registration of 3D images. This results in a mostly toroidal rotation. Its projection against q, i.e. the direction transverse to B and contained on magnetic surfaces, agrees well with the same projection of the stationary zonal flow velocity. This suggests that the parallel dynamic compensates the poloidal ExB drift on average, so as to yield a mostly toroidal motion. This explains why the ballooning character is preserved despite significant poloidal flows. The sign of the computed radial velocity correlates well with that of the stationary zonal flow shear rate, as already reported [2, 3]. This leads to either converging or diverging layers at local extrema of zonal flows. Most surprisingly, turbulent correlation time and length are affected differently in these 2 different layers, hence questioning the universal picture of turbulence decorrelation by zonal flows. Finally, the complex temporal dynamics of inferred velocities suggest a different role for zonal flow fluctuations. Quasilinear framework assumes that the linear relationship between perturbations hold in the non-linear regime. Phase relations between electric potential and pressure are investigated numerically. The heat flux is decomposed into the product of pressure and radial ExB velocity fluctuation amplitudes times the sine of the phase shift. Statistical analysis shows that the phase distribution is radially-uniform over the whole radial domain 0≤r/a≤1 and narrow around 0.3 rad ± 0.1 rad. The majority of the flux variance appears to be governed by the amplitude fluctuations. Those phase relations have been compared to the expected linear properties computed with the quasilinear code QuaLiKiz [4], run with time-averaged profiles. QuaLiKiz prediction for the phase shift is higher, around 0.6 rad , and exhibits a stronger radial dependency. The possible roles of nonlocal features and of the proximity to marginal stability are currently explored and will be reported.
Published: 2019

48. Persistence of linear ITG mode properties in flux-driven turbulent non-linear simulations

Author: Gillot, C., Dif-Pradalier, Guilhem, Sarazin, Y., Caschera, E., Ghendrih, Ph, Garbet, X., Grandgirard, V., Latu, G., Passeron, C., Bourdelle, C., Zarzoso, D., Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), École des Ponts ParisTech (ENPC), Physique des interactions ioniques et moléculaires (PIIM), and Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics::Fluid Dynamics, [PHYS]Physics [physics], Physics::Plasma Physics, Physics::Space Physics, Physics::Atmospheric and Oceanic Physics
Abstract: International audience; Objective: Find a reduced description for turbulence in tokamak plasmasMethod: Analysis of GYSELA simulation 3D output What are turbulent vortices’ dynamics?  How to reduce the description?Results:• Zonal flows act as toroidal motion, and zonal shear acts as radial motion• Zonal shear yields stationary tilt of turbulent eddies• Pressure-potential phase shift distribution is narrow, around quasi-linear value• QuaLiKiz linear prediction in qualitative agreement with GYSELA simulation
Published: 2019

49. On-plate localization and mapping for an inspection robot using ultrasonic guided waves: a proof of concept

Author: Pradalier, Cedric, POMAREDE, Pascal, Steckel, Jan, Georgia Tech Lorraine [Metz], Ecole Nationale Supérieure des Arts et Metiers Metz-Georgia Institute of Technology [Atlanta]-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Laboratoire d'Etude des Microstructures et de Mécanique des Matériaux (LEM3), Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Arts et Métiers Sciences et Technologies, HESAM Université (HESAM)-HESAM Université (HESAM), Active Perception Lab - Universiteit Antwerpen (APL), and Universiteit Antwerpen
Subjects: [SPI.ACOU]Engineering Sciences [physics]/Acoustics [physics.class-ph], [INFO.INFO-TS]Computer Science [cs]/Signal and Image Processing, [INFO.INFO-RB]Computer Science [cs]/Robotics [cs.RO]
Abstract: This paper presents a proof-of-concept for a local-ization and mapping system for magnetic crawlers performing inspection tasks on structures made of large metal plates. By relying on ultrasonic guided waves reflected from the plate edges, we demonstrate that it is possible to recover the plate geometry and robot trajectory to a precision comparable to the signal wavelength. The approach is tested using real acoustic signals acquired on test metal plates using lawnmower paths and random-walks. To the contrary of related works, this paper focuses on the practical details of the localization and mapping algorithm.
Published: 2019

50. Impact of Turbulence driven Asymmetries & Anisotropy on Neoclassical Transport

Author: Donnel, P., Garbet, X., Sarazin, Y., Grandgirard, V., Asahi, Y., Caschera, E., Dif-Pradalier, G., Ghendrih, Ph, Gillot, C., Latu, G., Passeron, C., Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), CEA Cadarache, Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information (CEA-LETI), Direction de Recherche Technologique (CEA) (DRT (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: [PHYS]Physics [physics], ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2019

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