Author: "Université Paris Saclay (COmUE)-ONERA" - Searchworks@Jio Institute Digital Library Search Results

Your search keyword '"Université Paris Saclay (COmUE)-ONERA"' showing total 72 results

Start Over Author "Université Paris Saclay (COmUE)-ONERA"

72 results on '"Université Paris Saclay (COmUE)-ONERA"'

1. Low frequency Raman spectroscopy of few-atomic-layer thick hBN crystals

Author: Bernard Plaçais, Léonard Schué, I. Stenger, Mohamed Boukhicha, Bruno Berini, Julien Barjon, Annick Loiseau, Groupe d'Etude de la Matière Condensée (GEMAC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'étude des microstructures [Châtillon] (LEM - ONERA - CNRS), Centre National de la Recherche Scientifique (CNRS)-ONERA, Laboratoire Pierre Aigrain (LPA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), ANR-14-CE08-0018,GoBN,Hétérostructures de graphènes blanc et noir(2014), European Project: 696656,H2020,H2020-Adhoc-2014-20,GrapheneCore1(2016), Université Paris Saclay (COmUE)-ONERA-Centre National de la Recherche Scientifique (CNRS), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), ONERA-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), ONERA-Centre National de la Recherche Scientifique (CNRS)-Université Paris Saclay (COmUE), ONERA - The French Aerospace Lab [Châtillon], and Université Paris Saclay (COmUE)-ONERA
Subjects: Materials science, FOS: Physical sciences, Nanotechnology, 02 engineering and technology, Nitride, 01 natural sciences, law.invention, symbols.namesake, law, 0103 physical sciences, General Materials Science, Thin film, 010306 general physics, Spectroscopy, ComputingMilieux_MISCELLANEOUS, Condensed Matter - Materials Science, Thin layers, Graphene, business.industry, Mechanical Engineering, Materials Science (cond-mat.mtrl-sci), General Chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Mechanics of Materials, symbols, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Optoelectronics, van der Waals force, 0210 nano-technology, business, Raman spectroscopy, Raman scattering
Abstract: Hexagonal boron nitride (hBN) has recently gained a strong interest as a strategic component in engineering van der Waals heterostructures built with two dimensional crystals such as graphene. This work reports micro-Raman measurements on hBN flakes made of a few atomic layers, prepared by mechanical exfoliation. The temperature dependence of the Raman scattering in hBN is investigated first such as to define appropriate measurements conditions suitable for thin layers avoiding undesirable heating induced effects. We further focus on the low frequency Raman mode corresponding to the rigid shearing oscillation between adjacent layers, found to be equal to 52.5 cm-1 in bulk hBN. For hBN sheets with thicknesses below typically 4 nm, the frequency of this mode presents discrete values, which are found to decrease down to 46.0(5) cm-1 for a three-layer hBN, in good agreement with the linear-chain model. This makes Raman spectroscopy a relevant tool to quantitatively determine the number of layers in ultra thin hBN sheets, below 8L.
Published: 2017
Full Text: View/download PDF

2. Modelling crystal plasticity by 3D dislocation dynamics and the finite element method: The Discrete-Continuous Model revisited

Author: Sébastien Groh, Benoit Devincre, Arjen Roos, R. Gatti, A. Vattré, F. Feyel, O. Jamond, Laboratoire d'étude des microstructures [Châtillon] (LEM - ONERA - CNRS), ONERA-Centre National de la Recherche Scientifique (CNRS), ONERA - The French Aerospace Lab [Châtillon], ONERA-Université Paris Saclay (COmUE), Department of Biomedical Engineering, Beijing Jiaotong University (BJTU), Université Paris Saclay (COmUE)-ONERA-Centre National de la Recherche Scientifique (CNRS), and Université Paris Saclay (COmUE)-ONERA
Subjects: Dislocation creep, Materials science, Continuous modelling, Mechanical Engineering, Slip (materials science), Eigenstrain, Mechanics, Plasticity, Condensed Matter Physics, Finite element method, Condensed Matter::Materials Science, Mechanics of Materials, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Boundary value problem, Dislocation, ComputingMilieux_MISCELLANEOUS
Abstract: A unified model coupling 3D dislocation dynamics (DD) simulations with the finite element (FE) method is revisited. The so-called Discrete-Continuous Model (DCM) aims to predict plastic flow at the (sub-)micron length scale of materials with complex boundary conditions. The evolution of the dislocation microstructure and the short-range dislocation–dislocation interactions are calculated with a DD code. The long-range mechanical fields due to the dislocations are calculated by a FE code, taking into account the boundary conditions. The coupling procedure is based on eigenstrain theory, and the precise manner in which the plastic slip, i.e. the dislocation glide as calculated by the DD code, is transferred to the integration points of the FE mesh is described in full detail. Several test cases are presented, and the DCM is applied to plastic flow in a single-crystal Nickel-based superalloy.
Published: 2014
Full Text: View/download PDF

3. Evidence Combination Based on Credal Belief Redistribution for Pattern Classification

Author: Jean Dezert, Zhun-ga Liu, Fabio Cuzzolin, Yu Liu, Northwestern Polytechnical University [Xi'an] (NPU), Naval Aeronautical and Astronautical University, DTIS, ONERA, Université Paris Saclay (COmUE) [Palaiseau], Université Paris Saclay (COmUE)-ONERA, and Oxford Brookes University
Subjects: [PHYS]Physics [physics], Discounting, business.industry, Computer science, Singleton, Applied Mathematics, 02 engineering and technology, Machine learning, computer.software_genre, [SPI]Engineering Sciences [physics], Computational Theory and Mathematics, Classifier fusion, Artificial Intelligence, Control and Systems Engineering, 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, Artificial intelligence, Belief function theory, business, Classifier (UML), computer
Abstract: International audience; Evidence theory, also called belief functions theory, provides an efficient tool to represent and combine uncertain information for pattern classification. Evidence combination can be interpreted, in some applications, as classifier fusion. The sources of evidence corresponding to multiple classifiers usually exhibit different classification qualities, and they are often discounted using different weights before combination. In order to achieve the best possible fusion performance, a new Credal Belief Redistribution (CBR) method is proposed to revise such evidence. The rationale of CBR consists in transferring belief from one class not just to other classes but also to the associated disjunctions of classes (i.e., meta-classes). As classification accuracy for different objects in a given classifier can also vary, the evidence is revised according to prior knowledge mined from its training neighbors. If the selected neighbors are relatively close to the evidence, a large amount of belief will be discounted for redistribution. Otherwise, only a small fraction of belief will enter the redistribution procedure. An imprecision matrix estimated based on these neighbors is employed to specifically redistribute the discounted beliefs. This matrix expresses the likelihood of misclassification (i.e., the probability of a test pattern belonging to a class different from the one assigned to it by the classifier). In CBR, the discounted beliefs are divided into two parts. One part is transferred between singleton classes, whereas the other is cautiously committed to the associated meta-classes. By doing this, one can efficiently reduce the chance of misclassification by modeling partial imprecision. The multiple revised pieces of evidence are finally combined by Dempster-Shafer rule to reduce uncertainty and further improve classification accuracy. The effectiveness of CBR is extensively validated on several real datasets from the UCI repository, and critically compared with that of other related fusion methods.
Published: 2020
Full Text: View/download PDF

4. Multi-technique physico-chemical characterization of particles generated by a gasoline engine: Towards measuring tailpipe emissions below 23 nm

Author: Noble, J.A., Betrancourt, C., Tritscher, T., Spielvogel, J., Rahman, M., Boies, A., Lee, K.F., Bhave, A.N., Legendre, S., Lancry, O., Kreutziger, P., Rieker, M., Minutolo, Patrizia, Commodo, Mario, D’Anna, Andrea, Nuns, Nicolas, Desgroux, Pascale, Mercier, Xavier, Ngo, Linh Dan, Duca, Dumitru, Carpentier, Yvain, Noble, Jennifer, Ikhenazene, Raouf, Vojkovic, Marin, Irimiea, Cornelia, Ortega, Ismael, Lefevre, Guillaume, Yon, Jérôme, Faccinetto, Alessandro, Therssen, Eric, Ziskind, Michael, Chazallon, Bertrand, Pirim, Claire, Focsa, Cristian, Laboratoire de Physique des Lasers, Atomes et Molécules - UMR 8523 (PhLAM), Université de Lille-Centre National de la Recherche Scientifique (CNRS), Physique Moléculaire aux Interfaces (PMI), Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Physicochimie des Processus de Combustion et de l’Atmosphère - UMR 8522 (PC2A), Laboratory of Atmospheric Chemistry [Paul Scherrer Institute] (LAC), Paul Scherrer Institute (PSI), International Islamic University Malaysia [Kuala Lumpur], HORIBA Scientific [France], Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement - UMR 8516 (LASIRE), Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Centrale Lille Institut (CLIL), ANR-11-LABX-0005,Cappa,Physiques et Chimie de l'Environnement Atmosphérique(2011), Centre National de la Recherche Scientifique (CNRS)-Université de Lille, Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences Moléculaires (ISM), Université Montesquieu - Bordeaux 4-Université Sciences et Technologies - Bordeaux 1-École Nationale Supérieure de Chimie et de Physique de Bordeaux (ENSCPB)-Centre National de la Recherche Scientifique (CNRS), International Centre for Diarrhoeal Disease Research, International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B), Laboratoire de Spectrochimie Infrarouge et Raman - UMR 8516 (LASIR), Université de Lille, Sciences et Technologies, DMPE, ONERA, Université Paris Saclay (COmUE) [Palaiseau], Université Paris Saclay (COmUE)-ONERA, Complexe de recherche interprofessionnel en aérothermochimie (CORIA), Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), and Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Atmospheric Science, 010504 meteorology & atmospheric sciences, [SDE.MCG]Environmental Sciences/Global Changes, Internal combustion engine, Nanoparticles, Physico-chemical characterization, Mass spectrometry, Emission modeling, Context (language use), 010501 environmental sciences, 01 natural sciences, 7. Clean energy, Ultrafine particle, Process engineering, Gasoline direct injection, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, General Environmental Science, Petrol engine, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], [PHYS.PHYS]Physics [physics]/Physics [physics], [CHIM.ORGA]Chemical Sciences/Organic chemistry, business.industry, Particulates, Characterization (materials science), 13. Climate action, Environmental science, Particle, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], business
Abstract: Particulate emissions from on-road motor vehicles are the focus of intensive current research due to the impact of the ambient particulate matter (PM) levels on climate and human health. Constant improvement in engine technology has led to significant decrease in the number and mass of emitted PM, but particular concern is raised nowadays by the ultrafine particles. In this context, there is a critical lack of certification procedures for the measurement of the smallest-size ( 23 nm) particulate matter emissions. To support the engine development process as well as future certification procedures, a measurement technology for sub-23 nm particles must be designed. The development of a reliable measurement procedure entails understanding the formation and evolution of particles from the engine to the tailpipe via multiple analytical techniques and theoretical simulations. We present here extensive experimental characterization of ultrafine particles emitted by a gasoline direct injection single-cylinder engine as particle generator. The particles were sampled using a cascade impactor which allows size-separation into 13 different size bins. Chemical characterization of the collected size-selected particles was performed using mass spectrometry, which gives access to detailed molecular information on chemical classes of critical interest such as organosulphates, oxygenated hydrocarbons, nitrogenated hydrocarbons, metals, or polycyclic aromatic hydrocarbons. Additionally, the morphology of the emitted particles was probed with atomic force (AFM) and scanning electron microscopy (SEM). Tip-Enhanced Raman Spectroscopy (TERS) was applied for the first time to sub-10 nm combustion-generated particles to gather information on their nanostructure. The extensive database built from these multiple experimental characterizations has been used as input of a theoretical approach to simulate and validate engine out-emissions. These studies were performed in the framework of the H2020 PEMS4Nano project which aims to the development of a robust, reliable and reproducible measurement technology for particles down to 10 nm for both chassis dyno and real driving emissions (RDE).
Published: 2020
Full Text: View/download PDF

5. Wind Hazard and Turbulence Monitoring at Airports with Lidar, Radar, and Mode-S Downlinks: The UFO Project

Author: Frédéric Barbaresco, L. Thobois, Dmitry A. Kovalev, A.C.P. Oude Nijhuis, Oleg A. Krasnov, Alexander Yarovoy, S. de Haan, Danielle Vanhoenacker-Janvier, A. Dolfi-Bouteyre, Richard Wilson, Delft University of Technology (TU Delft), LEOSPHERE, Thales Air Systems, Thales Group [France], Royal Netherlands Meteorological Institute (KNMI), DOTA, ONERA, Université Paris Saclay (COmUE) [Palaiseau], Université Paris Saclay (COmUE)-ONERA, Université Catholique de Louvain = Catholic University of Louvain (UCL), STRATO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), and UCL - SST/ICTM/ELEN - Pôle en ingénierie électrique
Subjects: [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Atmospheric Science, Radar, 010504 meteorology & atmospheric sciences, System of measurement, Doppler radar, Mode (statistics), 01 natural sciences, law.invention, 010309 optics, symbols.namesake, Lidar, 13. Climate action, law, 0103 physical sciences, Turbulence kinetic energy, symbols, Environmental science, Visibility, Doppler effect, Image resolution, Physics::Atmospheric and Oceanic Physics, 0105 earth and related environmental sciences, Remote sensing
Abstract: This article presents the prospects of measurement systems for wind hazards and turbulence at airports, which have been explored in the Ultrafast Wind Sensors (UFO) project. At France’s Toulouse–Blagnac Airport, in situ, profiling, and scanning sensors have been used to collect measurements, from which wind vectors and turbulence intensities are estimated. A scanning 1.5-µm coherent Doppler lidar and a solid state X-band Doppler radar have been developed with improved update rates, spatial resolution, and coverage. In addition, Mode-S data downlinks have been collected for data analysis. Wind vector and turbulence intensity retrieval techniques are applied to demonstrate the capabilities of these measurement systems. An optimal combination of remote measurement systems is defined for all weather monitoring at airports. In this combination, lidar and radar systems are complementary for clear-air and rainy conditions, which are formulated in terms of visibility and rain rate. The added value of the measurement systems for high-resolution numerical weather prediction models is estimated by an observing system experiment, and a positive impact on the local wind forecast is demonstrated.
Published: 2018
Full Text: View/download PDF

6. A new adaptive switching median filter for impulse noise reduction with pre-detection based on evidential reasoning

Author: Yi Yang, Jean Dezert, Zhe Zhang, Deqiang Han, Xi'an Jiaotong University (Xjtu), DTIS, ONERA, Université Paris Saclay (COmUE) [Palaiseau], Université Paris Saclay (COmUE)-ONERA, and School of Aerospace Xi’an Jiaotong University (SKLSVMS)
Subjects: Computer science, Noise reduction, Image processing, 02 engineering and technology, Impulse noise, Reduction (complexity), [SPI]Engineering Sciences [physics], IMPULSE NOISE, 0202 electrical engineering, electronic engineering, information engineering, Median filter, IMAGE DENOISING, [INFO]Computer Science [cs], [MATH]Mathematics [math], Electrical and Electronic Engineering, [PHYS]Physics [physics], EVIDENTIAL REASONING, business.industry, Noise spectral density, MULTI-CRITERIA DETECTION, Evidential reasoning approach, 020206 networking & telecommunications, Pattern recognition, Filter (signal processing), ADAPTIVE MEDIAN FILTERING, Filter design, Control and Systems Engineering, Computer Science::Computer Vision and Pattern Recognition, Signal Processing, 020201 artificial intelligence & image processing, Computer Vision and Pattern Recognition, Artificial intelligence, business, Software
Abstract: International audience; Image denoising is a fundamental problem in image processing. The switching filtering is a popular approach to reduce the impulse noise. It faces two challenges including the impulse noise detection and filter design. The traditional detection methods based on single criterion or multiple criteria encounter uncertainty problems and produce many miss-detections and false alarms, especially when the image is severely corrupted. In this paper, the uncertainties encountered in the impulse noise detection are addressed using the theory of belief functions, and a multi-criteria detection strategy for the impulse noise based on evidential reasoning is proposed. Based on the pre-detection, an adaptive median filter is designed, which adaptively determines the size of the filtering window according to the estimated global noise density and the degree of local corruption. Experimental results and related analyses show that our proposed image denoising method for the impulse noise has superior performance compared with several state-of-the-art denoising methods.
Published: 2018
Full Text: View/download PDF

7. A mixed-dimensional CutFEM methodology for the simulation of fibre-reinforced composites

Author: Pierre Kerfriden, Iulia Carmen Mihai, Susanne Claus, MINES ParisTech - École nationale supérieure des mines de Paris, Université Paris sciences et lettres (PSL), School of Engineering [Cardiff], Cardiff University, DTIS, ONERA, Université Paris Saclay (COmUE) [Palaiseau], Université Paris Saclay (COmUE)-ONERA, ONERA-Université Paris Saclay (COmUE), Centre des Matériaux (MAT), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), DTIS, ONERA, Université Paris Saclay [Palaiseau], and ONERA-Université Paris-Saclay
Subjects: Trace (linear algebra), Computer science, Computation, CutFEM, 010103 numerical & computational mathematics, [SPI.MECA.MSMECA]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Materials and structures in mechanics [physics.class-ph], 01 natural sciences, lcsh:TA168, Stress (mechanics), Mixed-dimensional analysis, Phase-field model, 0101 mathematics, Composite material, Nonconforming finite element method, Engineering (miscellaneous), Coupling, Computational model, Applied Mathematics, Quasi-1D structural elements, [INFO.INFO-NA]Computer Science [cs]/Numerical Analysis [cs.NA], [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation, Finite element method, Computer Science Applications, 010101 applied mathematics, Nonlinear system, LaTIn solver, lcsh:Systems engineering, Modeling and Simulation, Embedding, lcsh:Mechanics of engineering. Applied mechanics, lcsh:TA349-359
Abstract: International audience; We develop a novel unfitted finite element solver for composite materials with quasi-1D fibrous reinforcements. The method belongs to the class of mixed-dimensional non-conforming finite element solvers. The fibres are treated as 1D structural elements that may intersect the mesh of the embedding structure in an arbitrary manner. No meshing of the unidimensional elements is required. Instead, fibre solution fields are described using the trace of the background mesh. A reg-ularised "cut" finite element formulation is carefully designed to ensure that analyses using such non-conforming finite element descriptions are stable. We also design a dedicated primal/dual operator splitting scheme to resolve the coupling between structure and fibrous reinforcements efficiently. The novel computational strategy is applied to the solution of stiff computational models whereby fibrous reinforcements may lose their bond to the embedding material above a certain level of stress. It is shown that the primal-dual 1D/3D CutFEM scheme is convergent and well-behaved in variety of scenarios involving such highly nonlinear structural computations. keywords: mixed-dimensional analysis, quasi-1D structural elements, CutFEM, nonconforming finite element method, LaTIn solver, phase-field model, fibre-reinforced composite
Published: 2020
Full Text: View/download PDF

8. Time-response of a wind turbine: role of kinematics

Author: Lepetit, Thomas, DEMR, ONERA, Université Paris Saclay (COmUE) [Palaiseau], Université Paris Saclay (COmUE)-ONERA, Douvenot, Rémi, DEMR, ONERA, Université Paris Saclay [Palaiseau], and ONERA-Université Paris-Saclay
Subjects: [SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, [SPI.ELEC] Engineering Sciences [physics]/Electromagnetism
Abstract: International audience; During the course of a recent research project, we carried out a measurement campaign inthe south-east of France, near Narbonne. There, we measured the time-varying RCS ofmany wind turbines in operation, and gathered data for several manufacturers as well as indifferent environmental conditions. Thus, we did assemble a large database of wind turbinesignatures (S-band).Due to their very large electrical size as well as their rotation, wind turbines RCS variesgreatly, by several tens of dBs, over a small angular range or time interval. Therefore, tounderstand the origin of the main contributions to the RCS for a given measurement, it isessential to have a good knowledge of wind turbine kinematics. To make the most of ourdatabase, we thus gathered extensive SCADA data, with the help of wind turbines operators,to help correlate signatures with kinematics.In this contribution, we share the lessons learned from the collected SCADA data, highlightthe main factors underpinning wind turbines RCS, analyze the possible shortcomings of ourinterpretation, and discuss possible avenues for future comparison with simulations.
Published: 2019

9. Numerical simulation and modelling of the influence of high-amplitude acoustic waves on a two-phase jet: application to the field of liquid-propellant rocket propulsion

Author: Rutard, Nicolas, DMPE, ONERA, Université Paris Saclay (COmUE) [Palaiseau], Université Paris Saclay (COmUE)-ONERA, UNIVERSITE PARIS-SACLAY, and Sébastien DUCRUIX
Subjects: PRESSION RADIATION, [PHYS]Physics [physics], COMBUSTION INSTABILITIES, INJECTION COAXIALE, [SPI]Engineering Sciences [physics], SUBCRITICAL CONDITIONS, LES, REGIME SUBCRITIQUE, INSTABILITE COMBUSTION, COAXIAL INJECTION, RADIATION PRESSURE
Abstract: The occurrence of high-frequency combustion instabilities in liquid-propellant rocket engines can be detrimental to propulsion systems. Consequently, space actors need to strengthen their understanding of the mechanisms that cause these instabilities. To this end, numerical simulation has become more and more attractive over time. Under subcritical operating conditions, the oxidizer inside the combustion chamber is in a liquid state. In such a case, numerical simulation must be able to reproduce every interaction mechanism between acoustics and the atomization of the liquid phase, because it may influence the combustion stability. In this perspective, this study consists in 1) setting up a methodology for the numerical simulation of an atomized two-phase jet under acoustic modulation, 2) validating the restitution of all the response mechanisms of the jet to acoustics, and 3) using the results of the simulations to progress in the understanding of the involved physical phenomena. The simulation strategy that is used is based on the coupling between a 4-equation diffuse interface method to simulate the gas and the largest liquid structures of the flow, and an Eulerian statistical approach to model the spray. In this work, the numerical simulation of an atomized two-phase jet subjected to a high amplitude acoustic modulation shows a good restitution of the flattening of the liquid core and its influence on the atomization process of the jet. In particular, the liquid core is shortened and the spray widens in one particular direction. The coupling between the injection system and the acoustic cavity and its influence on the atomization process of the liquid are also reproduced. Finally, a simplified modeling of the flow used to complement the simulation results reveals a progressive deviation of the liquid core, and therefore of the drops resulting from its atomization, by the acoustic radiation force. Thus, this work opens the way to reactive simulations capable of faithfully reproducing two-phase flames under acoustic disturbances in order to study their impact on combustion stability.; L’occurrence d'instabilités de combustion de haute fréquence au sein des moteurs-fusées à ergols liquides peut s'avérer dommageable pour l'intégrité des systèmes propulsifs. Par conséquent, les acteurs du spatial souhaitent renforcer leur compréhension des mécanismes à l'origine de ces instabilités. Pour cela, la simulation numérique s'est révélée au fil du temps de plus en plus attractive. Dans le cas particulier d'un fonctionnement en régime subcritique, le comburant se trouve à l'état liquide dans la chambre de combustion. Pour reproduire fidèlement les écoulements associés à ce régime de fonctionnement, la simulation numérique doit pouvoir restituer les mécanismes d'interaction entre les perturbations acoustiques et le processus d'atomisation de la phase liquide, car ils peuvent influencer la stabilité de la combustion. Dans cette optique, cette étude consiste 1) à mettre en place une méthodologie de simulation numérique de jet diphasique atomisé sous excitation acoustique, 2) à valider la restitution de l'ensemble des mécanismes de réponse du jet aux ondes acoustiques, et 3) à s'appuyer sur les résultats des simulations pour progresser vers une meilleure compréhension des phénomènes physiques mis en jeu. La stratégie de simulation utilisée est basée sur le couplage entre une méthode à interface diffuse à 4 équations pour simuler le gaz et les plus grosses structures liquides de l'écoulement, et une approche statistique Eulérienne pour modéliser le spray de gouttes. Dans ces travaux, la simulation numérique d'un jet diphasique atomisé soumis à une excitation acoustique de haute amplitude montre une bonne restitution de l'aplatissement du cœur liquide et de son influence sur le processus d'atomisation du jet. Notamment, le cœur liquide est raccourci et le spray s'élargit dans la direction orthogonale à l'axe de propagation acoustique. Un couplage important d'ores et déjà observé expérimentalement entre le système d'injection et la cavité acoustique ainsi que son influence sur le processus d'atomisation de la phase liquide sont également reproduits. Enfin, une modélisation simplifiée de l'écoulement destinée à compléter les résultats des simulations révèle une déviation progressive du cœur liquide, et donc des gouttes issues de son atomisation, par la force de radiation acoustique. Ces travaux ouvrent ainsi la voie à des simulations réactives capables de reproduire fidèlement le comportement de flammes diphasiques sous perturbation acoustique en vue d'en étudier l'impact sur la stabilité de la combustion.
Published: 2019

10. Apprentissage multi-tâche de l'élévation et de la sémantique à partir d'images aériennes

Author: Marcela Carvalho, Pauline Trouvé-Peloux, Frédéric Champagnat, Bertrand Le Saux, Andrés Almansa, DTIS, ONERA, Université Paris Saclay (COmUE) [Palaiseau], ONERA-Université Paris Saclay (COmUE), Mathématiques Appliquées Paris 5 (MAP5 - UMR 8145), Université Paris Descartes - Paris 5 (UPD5)-Institut National des Sciences Mathématiques et de leurs Interactions (INSMI)-Centre National de la Recherche Scientifique (CNRS), DTIS, ONERA, Université Paris Saclay [Palaiseau], ONERA-Université Paris-Saclay, and Université Paris Saclay (COmUE)-ONERA
Subjects: FOS: Computer and information sciences, Computer Science - Machine Learning, RESEAU NEURONES, Computer science, Computer Vision and Pattern Recognition (cs.CV), 0211 other engineering and technologies, Computer Science - Computer Vision and Pattern Recognition, IMAGERIE HAUTE RESOLUTION, Multi-task learning, 02 engineering and technology, NEURAL NETWORKS, Semantics, Machine learning, computer.software_genre, CLASSIFICATION, Machine Learning (cs.LG), SEMANTIC SEGMENTATION, [SPI]Engineering Sciences [physics], CARTOGRAPHIE URBAINE, SINGLE VIEW DEPTH ESTIMATION, Satellite imagery, [INFO]Computer Science [cs], Electrical and Electronic Engineering, [MATH]Mathematics [math], TELEDETECTION, 021101 geological & geomatics engineering, AERIAL IMAGERY, [PHYS]Physics [physics], APPRENTISSAGE AUTOMATIQUE, Artificial neural network, business.industry, DEEP LEARNING, Deep learning, 15. Life on land, Geotechnical Engineering and Engineering Geology, Sensor fusion, Data set, MULTITASK LEARNING, Artificial intelligence, LIDAR AERIEN, business, computer
Abstract: Aerial or satellite imagery is a great source for land surface analysis, which might yield land use maps or elevation models. In this investigation, we present a neural network framework for learning semantics and local height together. We show how this joint multi-task learning benefits to each task on the large dataset of the 2018 Data Fusion Contest. Moreover, our framework also yields an uncertainty map which allows assessing the prediction of the model. Code is available at https://github.com/marcelampc/mtl_aerial_images ., Comment: Published IEEE Geoscience and Remote Sensing Letters. Code https://github.com/marcelampc/mtl_aerial_images
Published: 2019
Full Text: View/download PDF

11. Euclid preparation

Author: Collaboration, Euclid, Barnett, R., Warren, S. J., Mortlock, D. J., Cuby, J. -G., Conselice, C., Hewett, P. C., Willott, C. J., Auricchio, N., Balaguera-Antolínez, A., Baldi, M., Bardelli, S., Bellagamba, F., Bender, R., Biviano, A., Bonino, D., Bozzo, E., Branchini, E., Brescia, M., Brinchmann, J., Burigana, C., Camera, S., Capobianco, V., Carbone, C., Carretero, J., Carvalho, C. S., Castander, F. J., Castellano, M., Cavuoti, S., Cimatti, A., Clédassou, R., Congedo, G., Conversi, L., Copin, Y., Corcione, L., Coupon, J., Courtois, H. M., Cropper, M., Da Silva, A., Duncan, C. A. J., Dusini, S., Ealet, A., Farrens, S., Fosalba, P., Fotopoulou, S., Fourmanoit, N., Frailis, M., Fumana, M., Galeotta, S., Garilli, B., Gillard, W., Gillis, B. R., Graciá-Carpio, J., Grupp, F., Hoekstra, H., Hormuth, F., Israel, H., Jahnke, K., Kermiche, S., Kilbinger, M., Kirkpatrick, C. C., Kitching, T., Kohley, R., Kubik, B., Kunz, M., Kurki-Suonio, H., Laureijs, R., Ligori, S., Lilje, P. B., Lloro, I., Maiorano, E., Mansutti, O., Marggraf, O., Martinet, N., Marulli, F., Massey, R., Mauri, N., Medinaceli, E., Mei, S., Mellier, Y., Metcalf, R. B., Metge, J. J., Meylan, G., Moresco, M., Moscardini, L., Munari, E., Neissner, C., Niemi, S. M., Nutma, T., Padilla, C., Paltani, S., Pasian, F., Paykari, P., Percival, W. J., Pettorino, V., Polenta, G., Poncet, M., Pozzetti, L., Raison, F., Renzi, A., Rhodes, J., Rix, H. -W., Romelli, E., Roncarelli, M., Rossetti, E., Saglia, R., Sapone, D., Scaramella, R., Schneider, P., Scottez, V., Secroun, A., Serrano, S., Sirri, G., Stanco, L., Sureau, F., Tallada-Crespí, P., Tavagnacco, D., Taylor, A. N., Tenti, M., Tereno, I., Toledo-Moreo, R., Torradeflot, F., Valenziano, L., Vassallo, T., Wang, Y., Zacchei, A., Zamorani, G., Zoubian, J., Zucca, E., Aix Marseille Université (AMU), INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), Dipartimento de Fisica Roma Tre (DF-Roma3), Università degli Studi Roma Tre, Consiglio Nazionale delle Ricerche [Bologna] (CNR), Institut de Biologie Intégrative de la Cellule (I2BC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Sénescence et stabilité génomique (SEN), Département Biologie des Génomes (DBG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Biologie Intégrative de la Cellule (I2BC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Dipartimento di Astronomia, Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO), Centre National d'Études Spatiales [Toulouse] (CNES), Institut de Physique des 2 Infinis de Lyon (IP2I Lyon), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Mullard Space Science Laboratory (MSSL), University College of London [London] (UCL), Centre de Physique des Particules de Marseille (CPPM), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Istituto di Astrofisica Spaziale e Fisica Cosmica - Milano (IASF-MI), Royal Observatory Edinburgh (ROE), University of Edinburgh, Max Planck Institute for Extraterrestrial Physics (MPE), Max-Planck-Gesellschaft, Département d'Astrophysique (ex SAP) (DAP), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Department of Physics [Helsinki], Falculty of Science [Helsinki], University of Helsinki-University of Helsinki, Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), University of Helsinki, Institut Régional de Médecine Physique et de Réadaptation Louis Pierquin [Nancy] (IRR Louis Pierquin), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Institut d'Astrophysique de Paris (IAP), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Dipartimento di Fisica e Astronomia [Bologna], University of Waterloo [Waterloo], Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Dipartimento di Fisica, Universita` di Roma Tor Vergata, Università degli Studi di Roma Tor Vergata [Roma], INAF - Osservatorio Astronomico di Bologna (OABO), Department of Agricultural, Food and Environmental Sciences, University of Perugia (DSA3), Università degli Studi di Perugia (UNIPG), Department of Biochemistry [Lausanne], Université de Lausanne (UNIL), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), DEMR, ONERA, Université Paris Saclay (COmUE) [Palaiseau], Université Paris Saclay (COmUE)-ONERA, Antarctic Research a European Network for Astrophysics (ARENA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Biomécanique et Bioingénierie (BMBI), Université de Technologie de Compiègne (UTC)-Centre National de la Recherche Scientifique (CNRS), Continental Dynamics Laboratory [CAGS Beijing], Institute of Geology [CAGS Beijing] (CAGS), Chinese Academy of Geological Sciences [Beijing] (CAGS), Ministry of Land and Resources (MLR)-Ministry of Land and Resources (MLR)-Chinese Academy of Geological Sciences [Beijing] (CAGS), Ministry of Land and Resources (MLR)-Ministry of Land and Resources (MLR), Oncology Institute of Southern Switzerland, Euclid Collaboration, Euclid Primeval Universe Science Working Group, Università degli Studi Roma Tre = Roma Tre University (ROMA TRE), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Helsingin yliopisto = Helsingfors universitet = University of Helsinki-Helsingin yliopisto = Helsingfors universitet = University of Helsinki, Helsingin yliopisto = Helsingfors universitet = University of Helsinki, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Università degli Studi di Perugia = University of Perugia (UNIPG), Université de Lausanne = University of Lausanne (UNIL), ONERA-Université Paris Saclay (COmUE), Barnett R., Warren S.J., Mortlock D.J., Cuby J.-G., Conselice C., Hewett P.C., Willott C.J., Auricchio N., Balaguera-Antolinez A., Baldi M., Bardelli S., Bellagamba F., Bender R., Biviano A., Bonino D., Bozzo E., Branchini E., Brescia M., Brinchmann J., Burigana C., Camera S., Capobianco V., Carbone C., Carretero J., Carvalho C.S., Castander F.J., Castellano M., Cavuoti S., Cimatti A., Cledassou R., Congedo G., Conversi L., Copin Y., Corcione L., Coupon J., Courtois H.M., Cropper M., Da Silva A., Duncan C.A.J., Dusini S., Ealet A., Farrens S., Fosalba P., Fotopoulou S., Fourmanoit N., Frailis M., Fumana M., Galeotta S., Garilli B., Gillard W., Gillis B.R., Gracia-Carpio J., Grupp F., Hoekstra H., Hormuth F., Israel H., Jahnke K., Kermiche S., Kilbinger M., Kirkpatrick C.C., Kitching T., Kohley R., Kubik B., Kunz M., Kurki-Suonio H., Laureijs R., Ligori S., Lilje P.B., Lloro I., Maiorano E., Mansutti O., Marggraf O., Martinet N., Marulli F., Massey R., Mauri N., Medinaceli E., Mei S., Mellier Y., Metcalf R.B., Metge J.J., Meylan G., Moresco M., Moscardini L., Munari E., Neissner C., Niemi S.M., Nutma T., Padilla C., Paltani S., Pasian F., Paykari P., Percival W.J., Pettorino V., Polenta G., Poncet M., Pozzetti L., Raison F., Renzi A., Rhodes J., Rix H.-W., Romelli E., Roncarelli M., Rossetti E., Saglia R., Sapone D., Scaramella R., Schneider P., Scottez V., Secroun A., Serrano S., Sirri G., Stanco L., Sureau F., Tallada-Crespi P., Tavagnacco D., Taylor A.N., Tenti M., Tereno I., Toledo-Moreo R., Torradeflot F., Valenziano L., Vassallo T., Wang Y., Zacchei A., Zamorani G., Zoubian J., Zucca E., Astronomy, Helsinki Institute of Physics, Department of Physics, Université Paris-Sud - Paris 11 (UP11)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Université Paris-Sud - Paris 11 (UP11)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Université Paris-Sud - Paris 11 (UP11)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Institut de Biologie Intégrative de la Cellule (I2BC), Université Paris-Sud - Paris 11 (UP11)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Université Paris-Sud - Paris 11 (UP11)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Università di Bologna [Bologna] (UNIBO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Aix Marseille Université (AMU), Institut Régional de Médecine Physique et de Réadaptation [Nancy] (IRR), PSL Research University (PSL)-PSL Research University (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), DEMR, ONERA, Université Paris Saclay [Palaiseau], ONERA-Université Paris-Saclay, Université Paris-Sud - Paris 11 (UP11)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Biologie Intégrative de la Cellule (I2BC), Université Paris-Sud - Paris 11 (UP11)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Science and Technology Facilities Council, Science and Technology Facilities Council (STFC), Barnett, R., Warren, S. J., Mortlock, D. J., Cuby, J. -G., Conselice, C., Hewett, P. C., Willott, C. J., Auricchio, N., Balaguera-Antolinez, A., Baldi, M., Bardelli, S., Bellagamba, F., Bender, R., Biviano, A., Bonino, D., Bozzo, E., Branchini, E., Brescia, M., Brinchmann, J., Burigana, C., Camera, S., Capobianco, V., Carbone, C., Carretero, J., Carvalho, C. S., Castander, F. J., Castellano, M., Cavuoti, S., Cimatti, A., Cledassou, R., Congedo, G., Conversi, L., Copin, Y., Corcione, L., Coupon, J., Courtois, H. M., Cropper, M., Da Silva, A., Duncan, C. A. J., Dusini, S., Ealet, A., Farrens, S., Fosalba, P., Fotopoulou, S., Fourmanoit, N., Frailis, M., Fumana, M., Galeotta, S., Garilli, B., Gillard, W., Gillis, B. R., Gracia-Carpio, J., Grupp, F., Hoekstra, H., Hormuth, F., Israel, H., Jahnke, K., Kermiche, S., Kilbinger, M., Kirkpatrick, C. C., Kitching, T., Kohley, R., Kubik, B., Kunz, M., Kurki-Suonio, H., Laureijs, R., Ligori, S., Lilje, P. B., Lloro, I., Maiorano, E., Mansutti, O., Marggraf, O., Martinet, N., Marulli, F., Massey, R., Mauri, N., Medinaceli, E., Mei, S., Mellier, Y., Metcalf, R. B., Metge, J. J., Meylan, G., Moresco, M., Moscardini, L., Munari, E., Neissner, C., Niemi, S. M., Nutma, T., Padilla, C., Paltani, S., Pasian, F., Paykari, P., Percival, W. J., Pettorino, V., Polenta, G., Poncet, M., Pozzetti, L., Raison, F., Renzi, A., Rhodes, J., Rix, H. -W., Romelli, E., Roncarelli, M., Rossetti, E., Saglia, R., Sapone, D., Scaramella, R., Schneider, P., Scottez, V., Secroun, A., Serrano, S., Sirri, G., Stanco, L., Sureau, F., Tallada-Crespi, P., Tavagnacco, D., Taylor, A. N., Tenti, M., Tereno, I., Toledo-Moreo, R., Torradeflot, F., Valenziano, L., Vassallo, T., Wang, Y., Zacchei, A., Zamorani, G., Zoubian, J., and Zucca, E.
Subjects: statistical [Methods], education, Astrophysics, Surveys, Astronomy & Astrophysics, 01 natural sciences, black-holes, Photometry (optics), surveys, quasars: general, 0201 Astronomical and Space Sciences, 0103 physical sciences, ionization, luminosity function, 010303 astronomy & astrophysics, stellar, Physics, methods: statistical, 010308 nuclear & particles physics, ly-alpha emission, Sigma, general [Quasars], Astronomy and Astrophysics, Quasar, neutral hydrogen, accretion flows, z-similar-to-6 quasars, 115 Astronomy, Space science, Astrophysics - Astrophysics of Galaxies, Redshift, Space and Planetary Science, Methods: statistical, Quasars: general, reionization, digital sky survey, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Data release, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: We provide predictions of the yield of $78$ may be selected from Euclid $OYJH$ photometry alone, but selection over the redshift interval $77.5$ should be found in the DR1 data release, expected in 2024. It will be possible to determine the bright-end slope of the QLF, $7, Comment: Published in A&A. Updated to match accepted version
Published: 2019
Full Text: View/download PDF

12. Accuracy of Heat Load Transfer in a Quasi-Dynamic Fluid-Structure Interaction

Author: Moretti, Rocco, Lazareff, Marc, Errera, Marc, Feyel, Frédéric, Soubrié, Tristan, Benyoucef, Farid, DAAA, ONERA, Université Paris-Saclay (COmUE) [Châtillon], Université Paris Saclay (COmUE)-ONERA, Centre des Matériaux (MAT), MINES ParisTech - École nationale supérieure des mines de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Safran tech, Andheo, and Safran Aircraft Engines
Subjects: METHODE DIRICHLET-ROBIN, [PHYS]Physics [physics], TRANSIENT CHT, METHODES D'INTERPOLATION, INTERPOLATION METHODS, PRECISION DE LA SOLUTION, INTERACTION THERMIQUE, QUADRATURE DE GAUSS, DIRICHLET-ROBIN METHOD, [SPI]Engineering Sciences [physics], THERMAL INTERACTION, GAUSS QUADRATURE, SYSTEME COUPLE FLUIDE-STRUCTURE, SOLUTION ACCURACY
Abstract: This paper is devoted to investigate the temporal and spatial accuracy in transient conjugate heat transfer problems where the influence of unsteadi-ness in the fluid is supposed to be negligible. The numerical method is based on an iterative procedure with interpolated boundary conditions on the solid side. Emphasis is put on these interpolation procedures. First it is shown that a temporal interpolation is by no means the most appropriate way of estimating the flow boundary conditions prescribed on the coupled solid surfaces. In contrast, when these conditions are based on the heat flux/temperature linearity, significantly better results are obtained. Indeed, they compare very well against a reference solution provided by a non-iterative and non-interpolated coupled computation. Moreover, important improvements were made by adequately defining the integral contribution of the boundary condition using the Gauss points in the finite element solid code. Finally, it was also revealed that a relevant approximation of the heat transfer requires a sufficiently fine solid mesh at the interface.; Cet article est consacré à l'étude de la précision temporelle et spatiale dans les problèmes aérothermiques en régime transitoire où l'influence des effets instationnaires dans le fluide est supposée être négligeable. La méthode numérique est basée sur une procédure itérative avec des conditions aux limites interpolées sur l'interface solide. L'accent est mis sur ces procédures d'interpolation. Tout d'abord, il est montré qu'une interpolation temporelle n'est en aucun cas le moyen le plus approprié d'estimer les conditions limites de l'écoulement prescrites sur les surfaces solides couplées. En revanche, lorsque ces conditions sont basées sur la linéarité flux de chaleur/température, les résultats obtenus sont nettement meilleurs. En effet, la comparaison avec une solution de référence obtenue par un calcul couplé non itératif et non interpolé est satisfaisante. De plus, d'importantes améliorations ont été apportées en définissant adéquatement la contribution intégrale de la condition limite à l'aide des points de Gauss situés sur l'interfaces du solide. Enfin, il a également été révélé qu'une approximation pertinente du transfert de chaleur nécessite un maillage solide suffisamment fin à l'interface fluide-structure.
Published: 2019

13. Précision du calcul de la charge thermique dans des problèmes d'interaction fluide-structure quasi-instationnaire

Author: Moretti, Rocco, Lazareff, Marc, Errera, Marc, Feyel, Frédéric, Soubrié, Tristan, Benyoucef, Farid, DAAA, ONERA, Université Paris-Saclay (COmUE) [Châtillon], Université Paris Saclay (COmUE)-ONERA, Centre des Matériaux (MAT), MINES ParisTech - École nationale supérieure des mines de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Safran tech, Andheo, and Safran Aircraft Engines
Subjects: METHODE DIRICHLET-ROBIN, [PHYS]Physics [physics], TRANSIENT CHT, METHODES D'INTERPOLATION, INTERPOLATION METHODS, PRECISION DE LA SOLUTION, INTERACTION THERMIQUE, QUADRATURE DE GAUSS, DIRICHLET-ROBIN METHOD, [SPI]Engineering Sciences [physics], THERMAL INTERACTION, GAUSS QUADRATURE, SYSTEME COUPLE FLUIDE-STRUCTURE, SOLUTION ACCURACY
Abstract: This paper is devoted to investigate the temporal and spatial accuracy in transient conjugate heat transfer problems where the influence of unsteadi-ness in the fluid is supposed to be negligible. The numerical method is based on an iterative procedure with interpolated boundary conditions on the solid side. Emphasis is put on these interpolation procedures. First it is shown that a temporal interpolation is by no means the most appropriate way of estimating the flow boundary conditions prescribed on the coupled solid surfaces. In contrast, when these conditions are based on the heat flux/temperature linearity, significantly better results are obtained. Indeed, they compare very well against a reference solution provided by a non-iterative and non-interpolated coupled computation. Moreover, important improvements were made by adequately defining the integral contribution of the boundary condition using the Gauss points in the finite element solid code. Finally, it was also revealed that a relevant approximation of the heat transfer requires a sufficiently fine solid mesh at the interface.; Cet article est consacré à l'étude de la précision temporelle et spatiale dans les problèmes aérothermiques en régime transitoire où l'influence des effets instationnaires dans le fluide est supposée être négligeable. La méthode numérique est basée sur une procédure itérative avec des conditions aux limites interpolées sur l'interface solide. L'accent est mis sur ces procédures d'interpolation. Tout d'abord, il est montré qu'une interpolation temporelle n'est en aucun cas le moyen le plus approprié d'estimer les conditions limites de l'écoulement prescrites sur les surfaces solides couplées. En revanche, lorsque ces conditions sont basées sur la linéarité flux de chaleur/température, les résultats obtenus sont nettement meilleurs. En effet, la comparaison avec une solution de référence obtenue par un calcul couplé non itératif et non interpolé est satisfaisante. De plus, d'importantes améliorations ont été apportées en définissant adéquatement la contribution intégrale de la condition limite à l'aide des points de Gauss situés sur l'interfaces du solide. Enfin, il a également été révélé qu'une approximation pertinente du transfert de chaleur nécessite un maillage solide suffisamment fin à l'interface fluide-structure.
Published: 2019

14. Improvement of the Viscous Penalty Method for Particle-Resolved Simulations

Author: Chadil, Mohamed-Amine, Vincent, Stéphane, Estivalezes, Jean-Luc, Institut de Mécanique et d'Ingénierie de Bordeaux (I2M), Institut National de la Recherche Agronomique (INRA)-Université de Bordeaux (UB)-École Nationale Supérieure d'Arts et Métiers (ENSAM), Arts et Métiers Sciences et Technologies, HESAM Université (HESAM)-HESAM Université (HESAM)-Arts et Métiers Sciences et Technologies, HESAM Université (HESAM)-HESAM Université (HESAM)-Institut Polytechnique de Bordeaux-Centre National de la Recherche Scientifique (CNRS), Institut de mécanique des fluides de Toulouse (IMFT), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées, Laboratoire Modélisation et Simulation Multi-Echelle (MSME), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université Gustave Eiffel, ONERA / DMPE, Université de Toulouse [Toulouse], PRES Université de Toulouse-ONERA, Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université Gustave Eiffel (UNIV GUSTAVE EIFFEL), ONERA - The French Aerospace Lab [Palaiseau], Université Paris Saclay (COmUE)-ONERA, HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-Arts et Métiers Sciences et Technologies, HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-Institut Polytechnique de Bordeaux-Centre National de la Recherche Scientifique (CNRS), and ONERA-PRES Université de Toulouse
Subjects: Physics::Fluid Dynamics, [PHYS]Physics [physics], [SPI]Engineering Sciences [physics], One-Fluid Model, Staggered Grids, Particle-Resolved DNS, Viscous Penalty Method, [SPI.MECA.MEFL]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph], Finite Volumes
Abstract: International audience; A numerical study of the parameters controlling the viscous penalty method is investigated to better set up Particle-Resolved Direct Numerical Simulations (PR-DNS) of particulate flows. Based on this analysis, improvements of the methods are proposed in order to reach an almost second order convergence in space. The viscous penalty method is validated in Stokes regime by simulating a uniform flow past a fixed isolated cylinder. Moreover, it is also utilized in moderate Reynolds number regime for a uniform flow past a square configuration of cylinder and compared in terms of friction factor to the well-known Ergun correlation.
Published: 2019
Full Text: View/download PDF

15. Infrared Hyperspectral and Ultraviolet Remote Measurements of Volcanic Gas Plume at MT Etna during IMAGETNA Campaign

Author: Y. Ferrec, Giuseppe Salerno, Tommaso Caltabiano, Stéphane Langlois, Delphy Rodriguez, Tjarda Roberts, Charlotte Segonne, Alessandro La Spina, Nathalie Huret, Laurence Croizé, Stéphane Chevrier, Valéry Catoire, Sébastien Payan, Armande Pola Fossi, Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National d’Études Spatiales [Paris] (CNES), TROPO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Istituto Nazionale di Geofisica e Vulcanologia - Sezione di Catania (INGV), Istituto Nazionale di Geofisica e Vulcanologia, DOTA, ONERA, Université Paris Saclay (COmUE) [Palaiseau], Université Paris Saclay (COmUE)-ONERA, Thales Air Systems, Thales Group [France], ANR-10-LABX-0100,VOLTAIRE,Geofluids and Volatil elements – Earth, Atmosphere, Interfaces – Resources and Environment(2010), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), ONERA-Université Paris Saclay (COmUE), PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Centre National d’Études Spatiales [Paris] (CNES), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), DOTA, ONERA, Université Paris Saclay [Palaiseau], ONERA-Université Paris-Saclay, and ANR: 10-LABX-0100,VOLTAIRE,Geofluids and Volatil elements – Earth, Atmosphere, Interfaces – Resources and Environment(2010)
Subjects: Daytime, 010504 meteorology & atmospheric sciences, Infrared, Astrophysics::High Energy Astrophysical Phenomena, Science, Infrared spectroscopy, Context (language use), 010502 geochemistry & geophysics, medicine.disease_cause, 01 natural sciences, 7. Clean energy, Physics::Geophysics, remote sensing, data retrieval, medicine, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, Computer Science::Databases, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Remote sensing, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], geography, Radiometer, geography.geographical_feature_category, volcanic plume, Hyperspectral imaging, hyperspectral, radiative transfer, Volcano, 13. Climate action, General Earth and Planetary Sciences, Astrophysics::Earth and Planetary Astrophysics, Ultraviolet
Abstract: International audience; Quantification of gaseous emission fluxes from volcanoes can yield valuable insights on processes occurring in the Earth's interior as part of hazard monitoring. It is also an important task in the framework of climate change, in order to refine estimates of natural emissions. Passive open-path UltraViolet (UV) scattered observation by UV camera allows the imaging of volcanic plumes and evaluation of sulfur dioxide (SO 2) fluxes at high temporal resolution during daytime. Another technique of imaging is now available in the InfraRed (IR) spectral domain. Infrared hyperspectral imagers have the potential to overcome the boundary of daytime sampling of the UV, providing measurements also during the night and giving access simultaneously to additional relevant gas species. In this context the IMAGETNA campaign of measurements took place at Mt Etna (Italy) in June 2015. Three different IR imagers (commercial and under developments) were deployed, together with a Fourier Transform InfraRed spectrometer (FTIR) instrument, a UV camera, a Long Wavelength InfraRed (LWIR) camera and a radiometer. We present preliminary results obtained by the two IR cameras under development, and then the IR hyperspectral imager results, coming from full physics retrieval, are compared to those of the UV camera. The comparison points out an underestimation of the SO2 Slant Column Densities (SCD) of the UV camera by a factor of 3.6. The detailed study of the retrieved SO2 SCD highlights the promising application of IR imaging in volcanology for remotely volcanic plume gas measurements. It also provides a way to investigate uncertainties in the SO2 SCD imaging in the UV and the IR.
Published: 2019
Full Text: View/download PDF

16. Continuity of Pontryagin Extremals with Respect to Delays in Nonlinear Optimal Control

Author: Bruno Hérissé, Riccardo Bonalli, Emmanuel Trélat, Laboratoire Jacques-Louis Lions (LJLL (UMR_7598)), Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Control And GEometry (CaGE ), Laboratoire Jacques-Louis Lions (LJLL), Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Inria de Paris, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), DTIS, ONERA, Université Paris Saclay (COmUE) [Palaiseau], ONERA-Université Paris Saclay (COmUE), and Université Paris Saclay (COmUE)-ONERA
Subjects: Time-delayed systems, 0209 industrial biotechnology, Control and Optimization, 02 engineering and technology, Network topology, 01 natural sciences, Projection (linear algebra), 020901 industrial engineering & automation, Shooting method, Dimension (vector space), Pontryagin extremals, Nonlinear optimal control, Shooting method for problems with delays, FOS: Mathematics, Applied mathematics, 0101 mathematics, Mathematics - Optimization and Control, Mathematics, Continuity with respect to delays, Applied Mathematics, 010102 general mathematics, State (functional analysis), Optimal control, AMS subject classifications. 49J15, 49K15, 49K40, Optimization and Control (math.OC), Trajectory, [MATH.MATH-OC]Mathematics [math]/Optimization and Control [math.OC], Constant (mathematics)
Abstract: Consider a general nonlinear optimal control problem in finite dimension, with constant state and/or control delays. By the Pontryagin Maximum Principle, any optimal trajectory is the projection of a Pontryagin extremal. We establish that, under appropriate assumptions, Pontryagin extremals depend continuously on the parameter delays, for adequate topologies. The proof of the continuity of the trajectory and of the control is quite easy, however, for the adjoint vector, the proof requires a much finer analysis. The continuity property of the adjoint with respect to the parameter delay opens a new perspective for the numerical implementation of indirect methods, such as the shooting method. We also discuss the sharpness of our assumptions., arXiv admin note: text overlap with arXiv:1709.04383
Published: 2019
Full Text: View/download PDF

17. Algorithmes de détection et de localisation en zone masquée

Author: Thai, Khac-Phuc-Hung, Rabaste, Olivier, Bosse, Jonathan, POULLIN, Dominique, Hinostroza, Israel, Letertre, Thierry, Chonavel, Thierry, DEMR, ONERA, Université Paris Saclay (COmUE) [Palaiseau], Université Paris Saclay (COmUE)-ONERA, Sondra, CentraleSupélec, Université Paris-Saclay (COmUE) (SONDRA), ONERA-CentraleSupélec-Université Paris Saclay (COmUE), Lab_STICC_TB_CID_TOMS, Mathématiques Appliquées Paris 5 (MAP5 - UMR 8145), Université Paris Descartes - Paris 5 (UPD5)-Institut National des Sciences Mathématiques et de leurs Interactions (INSMI)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Descartes - Paris 5 (UPD5)-Institut National des Sciences Mathématiques et de leurs Interactions (INSMI)-Centre National de la Recherche Scientifique (CNRS), IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT), Département Signal et Communications (IMT Atlantique - SC), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), DEMR, ONERA, Université Paris Saclay [Palaiseau], ONERA-Université Paris-Saclay, Sondra, CentraleSupélec, Université Paris-Saclay (SONDRA), and ONERA-CentraleSupélec-Université Paris-Saclay
Subjects: around-the-corner radar, multipath exploitation, [INFO.INFO-TS]Computer Science [cs]/Signal and Image Processing, detection and localization algorithm, urban environment, NLOS, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing, urban radar
Abstract: International audience; Detection and localization in urban environments is a very recent radar problem. In this article, we investigate the possibility of detecting and locating targets in NLOS areas with a single portable radar by exploiting multipath returns. We propose two algorithms which handle the information provided by multipath returns in different ways to detect and estimate the NLOS target position. We also present an original method to select the number of paths to take into account in the algorithms in order to maximize detection probabilities. Numerical results show good efficiency of the proposed algorithms for problems of both detection and localization. We show that applying these algorithms improves detection performance compared to a classic matched filter in a typical urban scenario. Experimental results on a real data set allow us to validate our multipath model in urban environments, and in particular to show that it is possible to retrieve the target location even with rough knowledge of the scene geometry.
Published: 2019
Full Text: View/download PDF

18. Adaptive optics precompensation of a GEO feeder link : the FEEDELIO experiment

Author: Serge Meimon, C. Petit, F. Mendez, P. Perrault, J. Montri, N. Védrenne, C. B. Lim, Jean-Marc Conan, V. Michau, Zoran Sodnik, Jean-François Sauvage, Bruno Fleury, C. Voland, A. Montmerle-Bonnefois, DOTA, ONERA, Université Paris Saclay [Châtillon], ONERA-Université Paris-Saclay, Agence Spatiale Européenne (ESA), European Space Agency (ESA), European Space Research and Technology Center [Noordwijk, The Netherlands] (ESRTC), DOTA, ONERA, Université Paris Saclay (COmUE) [Châtillon], and Université Paris Saclay (COmUE)-ONERA
Subjects: [PHYS]Physics [physics], [PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], Computer science, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, 7. Clean energy, 010309 optics, Light propagation, 0103 physical sciences, Key (cryptography), Electronic engineering, [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, Atmospheric turbulence, 0210 nano-technology, Adaptive optics, Link (knot theory), Throughput (business), Refractive index, ComputingMilieux_MISCELLANEOUS
Abstract: The FEEDELIO experiment took place in Tenerife in April 2019, and proved the efficiency of Adaptive-Optics pre-compensation of atmospheric turbulence, which is a key technology for achieving very high throughput optical GEO feeder links.
Published: 2019
Full Text: View/download PDF

19. Automatic Target Detection for Sparse Hyperspectral Images

Author: Bitar, Ahmad W., Jean-Philippe Ovarlez, Loong-Fah Cheong, Ali Chehab, Sondra, CentraleSupélec, Université Paris-Saclay (COmUE) (SONDRA), Université Paris Saclay (COmUE)-CentraleSupélec-ONERA, American University of Beirut [Beyrouth] (AUB), DEMR, ONERA, Université Paris Saclay (COmUE) [Palaiseau], Université Paris Saclay (COmUE)-ONERA, National University of Singapore (NUS), Saurabh Prasad, Jocelyn Chanussot, Bitar, Ahmad W., and ONERA-CentraleSupélec-Université Paris Saclay (COmUE)
Subjects: FOS: Computer and information sciences, [STAT.AP]Statistics [stat]/Applications [stat.AP], [INFO.INFO-TS] Computer Science [cs]/Signal and Image Processing, Computer Vision and Pattern Recognition (cs.CV), Image and Video Processing (eess.IV), Computer Science - Computer Vision and Pattern Recognition, [MATH] Mathematics [math], Electrical Engineering and Systems Science - Image and Video Processing, [INFO.INFO-TI] Computer Science [cs]/Image Processing [eess.IV], [STAT.AP] Statistics [stat]/Applications [stat.AP], [INFO.INFO-TS]Computer Science [cs]/Signal and Image Processing, [INFO.INFO-TI]Computer Science [cs]/Image Processing [eess.IV], FOS: Electrical engineering, electronic engineering, information engineering, [MATH]Mathematics [math]
Abstract: In this work, a novel target detector for hyperspectral imagery is developed. The detector is independent on the unknown covariance matrix, behaves well in large dimensions, distributional free, invariant to atmospheric effects, and does not require a background dictionary to be constructed. Based on a modification of the robust principal component analysis (RPCA), a given hyperspectral image (HSI) is regarded as being made up of the sum of a low-rank background HSI and a sparse target HSI that contains the targets based on a pre-learned target dictionary specified by the user. The sparse component is directly used for the detection, that is, the targets are simply detected at the non-zero entries of the sparse target HSI. Hence, a novel target detector is developed, which is simply a sparse HSI generated automatically from the original HSI, but containing only the targets with the background is suppressed. The detector is evaluated on real experiments, and the results of which demonstrate its effectiveness for hyperspectral target detection especially when the targets are well matched to the surroundings., Comment: Accepted for publication in the book "Hyperspectral Image Analysis - Advances in Signal Processing and Machine Learning". arXiv admin note: text overlap with arXiv:1711.08970, arXiv:1808.06490
Published: 2019
Full Text: View/download PDF

20. Distance transform regression for spatially-aware deep semantic segmentation

Author: Nicolas Audebert, Sébastien Lefèvre, Alexandre Boulch, Bertrand Le Saux, DTIS, ONERA, Université Paris Saclay [Palaiseau], ONERA-Université Paris-Saclay, Environment observation with complex imagery (OBELIX), Université de Bretagne Sud (UBS)-SIGNAUX ET IMAGES NUMÉRIQUES, ROBOTIQUE (IRISA-D5), Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Université de Bretagne Sud (UBS)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-CentraleSupélec-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Université de Rennes (UNIV-RENNES)-CentraleSupélec-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-CentraleSupélec, DTIS, ONERA, Université Paris Saclay (COmUE) [Palaiseau], Université Paris Saclay (COmUE)-ONERA, CentraleSupélec-Télécom Bretagne-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National de Recherche en Informatique et en Automatique (Inria)-École normale supérieure - Rennes (ENS Rennes)-Université de Bretagne Sud (UBS)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Télécom Bretagne-Université de Rennes 1 (UR1), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National de Recherche en Informatique et en Automatique (Inria)-École normale supérieure - Rennes (ENS Rennes)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), ONERA-Université Paris Saclay (COmUE), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)
Subjects: FOS: Computer and information sciences, Low overhead, Computer science, Computer Vision and Pattern Recognition (cs.CV), Computer Science - Computer Vision and Pattern Recognition, 02 engineering and technology, [INFO.INFO-NE]Computer Science [cs]/Neural and Evolutionary Computing [cs.NE], Regularization (mathematics), Convolutional neural network, 0202 electrical engineering, electronic engineering, information engineering, FOS: Electrical engineering, electronic engineering, information engineering, Segmentation, Neural and Evolutionary Computing (cs.NE), business.industry, Image and Video Processing (eess.IV), Process (computing), Computer Science - Neural and Evolutionary Computing, [INFO.INFO-CV]Computer Science [cs]/Computer Vision and Pattern Recognition [cs.CV], 020207 software engineering, Pattern recognition, Electrical Engineering and Systems Science - Image and Video Processing, Regression, Signal Processing, Spatial cues, 020201 artificial intelligence & image processing, Computer Vision and Pattern Recognition, Artificial intelligence, business, Distance transform, Software
Abstract: International audience; Understanding visual scenes relies more and more on dense pixel-wise classification obtained via deep fully convolutional neural networks. However, due to the nature of the networks, predictions often suffer from blurry boundaries and ill-segmented shapes, fueling the need for post-processing. This work introduces a new semantic segmentation regularization based on the regression of a distance transform. After computing the distance transform on the label masks, we train a FCN in a multi-task setting in both discrete and continuous spaces by learning jointly classification and distance regression. This requires almost no modification of the network structure and adds a very low overhead to the training process. Learning to approximate the distance transform back-propagates spatial cues that implicitly regularizes the segmentation. We validate this technique with several architectures on various datasets, and we show significant improvements compared to competitive baselines.
Published: 2019
Full Text: View/download PDF

21. DVB-T Airborne passive radar: Clutter Analysis and Experimental Results

Author: Dominique Poullin, Clement Berthillot, Agnes Santori, Marc Lesturgie, Olivier Rabaste, André, Cécile, Sondra, CentraleSupélec, Université Paris-Saclay (COmUE) (SONDRA), ONERA-CentraleSupélec-Université Paris Saclay (COmUE), Centre de Recherche de l'École de l'air (CReA), Armée de l'air et de l'espace, DEMR, ONERA, Université Paris Saclay (COmUE) [Palaiseau], Université Paris Saclay (COmUE)-ONERA, ONERA - The French Aerospace Lab [Palaiseau], and ONERA-Université Paris Saclay (COmUE)
Subjects: [PHYS]Physics [physics], 020301 aerospace & aeronautics, RADAR PASSIF, Computer science, [SPI] Engineering Sciences [physics], AEROPORTE, Transmitter, 0211 other engineering and technologies, ComputerApplications_COMPUTERSINOTHERSYSTEMS, 02 engineering and technology, Signal, Object detection, Passive radar, [PHYS] Physics [physics], [SPI]Engineering Sciences [physics], symbols.namesake, Bistatic radar, 0203 mechanical engineering, symbols, Clutter, DVB-T, Doppler effect, 021101 geological & geomatics engineering, Remote sensing
Abstract: International audience; An experimental airborne passive radar system exploiting DVB-T signal has been developped and embedded on a motoglider dedicated to test flight. Two experimental campaigns have been run to acquire of real data. This article presents the level of the different contributors observed in the experimental data and analyses the bistatic clutter spread.
Published: 2019

22. Near infrared adaptive optics flood illumination retinal angiography

Author: Elena, Gofas-Salas, Pedro, Mecê, Laurent, Mugnier, Aurélie Montmerle, Bonnefois, Cyril, Petit, Kate, Grieve, José, Sahel, Michel, Paques, Serge, Meimon, DOTA, ONERA, Université Paris Saclay (COmUE) [Palaiseau], Université Paris Saclay (COmUE)-ONERA, Institut de la Vision, Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut National de la Santé et de la Recherche Médicale (INSERM), Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts (CHNO), University of Pittsburgh School of Medicine, and Pennsylvania Commonwealth System of Higher Education (PCSHE)
Subjects: [SDV.IB.IMA]Life Sciences [q-bio]/Bioengineering/Imaging, Article
Abstract: International audience; Image-based angiography is a well-adapted technique to characterize vasculature, and has been used in retinal neurovascular studies. Because the microvasculature is of particular interest, being the site of exchange between blood and tissue, a high spatio-temporal resolution is required, implying the use of adaptive optics ophthalmoscopes with a high frame rate. Creating the opportunity for decoupled stimulation and imaging of the retina makes the use of near infrared (NIR) imaging light desirable, while the need for a large field of view and a lack of distortion implies the use of a flood illumination-based setup. However, flood-illumination NIR video sequences of erythrocytes, or red blood cells (RBC), have a limited contrast compared to scanning systems and visible light. As a result, they cannot be processed via existing image-based angiography methods. We have therefore developed a new computational method relying on a spatio-temporal filtering of the sequence to isolate blood flow from noise in low-contrast sequences. Applying this computational approach enabled us to perform angiography with an adaptive optics flood illumination ophthalmoscope (AO-FIO) using NIR light, both in bright-field and dark-field modalities. Finally, we demonstrate the capabilities of our system to differentiate blood flow velocity on a retinal capillary network in vivo.
Published: 2019
Full Text: View/download PDF

23. Tuning bimetallic catalysts for a selective growth of SWCNTs

Author: Salomé Forel, Annick Loiseau, Hakim Amara, Laure Catala, Christophe Bichara, Alice Castan, Vincent Huc, Ileana Florea, Costel Sorin Cojocaru, Talal Mallah, Frédéric Fossard, Laboratoire de physique des interfaces et des couches minces [Palaiseau] (LPICM), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Laboratoire d'étude des microstructures [Châtillon] (LEM - ONERA - CNRS), Université Paris Saclay (COmUE)-ONERA-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique du solide (Namur) (LPS), Facultés Universitaires Notre Dame de la Paix (FUNDP) - Namur, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace, Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Université de Strasbourg (UNISTRA), Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Centre de recherche de la matière condensée et des nanosciences (CRMCN), Université de la Méditerranée - Aix-Marseille 2-Université Paul Cézanne - Aix-Marseille 3-Centre National de la Recherche Scientifique (CNRS), Service de Chimie Moléculaire (SCM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), LEM, UMR 104 CNRS-ONERA, Université Paris Saclay (COmUE) [Châtillon], ONERA-Centre National de la Recherche Scientifique (CNRS)-Université Paris Saclay (COmUE), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Centre Interdisciplinaire de Nanoscience de Marseille (CINaM), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU), ANR-13-BS10-0015,SYNAPSE,Synthèse de Nanotubes à Propriétés Spécifiques(2013), ANR-10-EQPX-0050,TEMPOS,Microscopie electronique en transmission sur le plateau Palaiseau Orsay Saclay(2010), European Project: 604472,EC:FP7:NMP,FP7-NMP-2013-EU-Japan,IRENA(2013), Université Paris-Sud - Paris 11 (UP11)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Coalescence (physics), Materials science, Condensed Matter - Mesoscale and Nanoscale Physics, chemistry.chemical_element, Nanoparticle, FOS: Physical sciences, 02 engineering and technology, Applied Physics (physics.app-ph), Physics - Applied Physics, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Ruthenium, Catalysis, chemistry, Chemical engineering, Phenomenological model, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], General Materials Science, Solubility, 0210 nano-technology, Carbon, Bimetallic strip
Abstract: Recent advances in structural control during the synthesis of SWCNTs have in common the use of bimetallic nanoparticles as catalysts, despite the fact that their exact role is not fully understood. We therefore analyze the effect of the catalyst' s chemical composition on the structure of the resulting SWCNTs by comparing three bimetallic catalysts (FeRu, CoRu and NiRu). A specific synthesis protocol is designed to impede the catalyst nanoparticle coalescence mechanisms and stabilize their diameter distributions throughout the growth. Owing to the ruthenium component which has a limited carbon solubility, tubes grow in tangential mode and their diameter is close to that of their seeding nanoparticle. By using as-synthesized SWCNTs as a channel material in field effect transistors, we show how the chemical composition of the catalysts and temperature can be used as parameters to tune the diameter distribution and semiconducting-to-metallic ratio of SWCNT samples. Finally, a phenomenological model, based on the dependence of the carbon solubility as a function of catalyst nanoparticle size and nature of the alloying elements, is proposed to interpret the results., 10 pages, 6 figures
Published: 2018
Full Text: View/download PDF

24. Around the Corner Radar : Detection and localization of an NLOS target in urban environment

Author: Thai, Khac Phuc Hung, DEMR, ONERA, Université Paris Saclay (COmUE) [Palaiseau], Université Paris Saclay (COmUE)-ONERA, Université Européenne de Bretagne, Thierry Chonavel, André, Cécile, Département Signal et Communications (IMT Atlantique - SC), IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Lab-STICC_IMTA_CID_TOMS, Laboratoire des sciences et techniques de l'information, de la communication et de la connaissance (Lab-STICC), École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT), and Ecole nationale supérieure Mines-Télécom Atlantique
Subjects: PARTICLE FILTER, Radar ‘’around the corner’’, Urban environment, LOCALIZATION, MULTI-TRAJETS, [STAT.OT]Statistics [stat]/Other Statistics [stat.ML], RADAR, DETECTION, Détection, LOCALISATION, TRACKING, MULTIPATH, PISTAGE, FILTRE PARTICULAIRE, URBAN ENVIRONEMENT, Around the corner radar, NLOS, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing, MILIEU URBAIN, [SPI.SIGNAL] Engineering Sciences [physics]/Signal and Image processing
Abstract: The applications of radar techniques to the urban environment constitute an emerging subject. One of the main difficulties is related to the complexity of the propagation environment induced by the buildings present in the scene. Indeed, unlike conventional radar applications where the target is in line of sight of the radar, the presence of these buildings generates on the one hand shadow areas within which a target is not in line of sight, and on the other hand, many multipaths produced by reflections and diffractions on the surrounding surfaces. Classically, these multipaths are often seen as an inconvenience, limiting radar detection capabilities. However these multipaths can also be exploited to the advantage of the radar to detect and locate targets located in the shadows areas (target in NLOS).The objective of this thesis work is therefore to develop signal processing methods allowing the detection and localization of a target located in shadow areas in urban environment and to apply these techniques for detecting and locating a target in NLOS from realistic or even real signals.For this, we first proposed two solutions for detection and localization of a target by exploiting multipath information: the FMU algorithm which is based on a projection of the received signal on the subspace defined by the delays of the multipaths and the SLC algorithm that is based on a non-coherent integration of multipath energy. We have also improved on one hand our detection solution by proposing a method for selecting the number of paths based on the optimization of the probability of detection, and on the other hand our localization solution by proposing to use some penalization enabling to mitigate the ambiguity problem inherent to the "around-the-corner" problem. In a second step, we developed two particle filters to track a target in urban environment in the presence of multipaths. These algorithms have been applied to real data and showed promising results: even with an approximate knowledge of the geometry of the scene, it has been possible to detect, locate and track a target by exploiting only the information on multipath delays., Les applications des techniques radar au milieu urbain constituent un domaine émergent. Une des difficultés principale est liée à la complexité du milieu de propagation induit par les bâtiments présents dans la scène. En effet, contrairement aux applications radar classiques où la cible est en ligne de vue du radar, la présence de ces bâtiments génère d’une part des zones d’ombre à l’intérieur desquelles une cible n’est pas en visibilité directe, et d’autre part de nombreux multi-trajets produits par les possibles réflexions et diffractions sur les surfaces environnantes. Ces multi-trajets sont souvent vus comme une gêne, limitant les capacités de détection en radar. Or ils peuvent aussi être exploités à l’avantage du radar afin de détecter et localiser des cibles situées dans les zones d’ombre (cible en NLOS).L’objectif de ce travail de thèse est donc la mise en place de méthodes de traitement du signal permettant la détection et la localisation d’une cible en NLOS en milieu urbain et l’application de ces techniques pour détecter et localiser une cible en NLOS à partir de signaux réalistes voire réels.Pour cela, nous avons proposé dans un premier temps deux solutions pour la détection et la localisation de la cible en exploitant les multi-trajets : l’algorithme FMU qui est basé sur une projection du signal reçu sur le sous-espace défini par les retards des multi-trajets et l’algorithme SLC qui est basé sur une intégration non cohérente de l’énergie des multi-trajets. Nous avons également affiné d’une part notre solution de détection en proposant une méthode de sélection du nombre de trajets fondée sur l’optimisation de la probabilité de détection, et d’autre part notre solution de localisation en proposant d’utiliser des critères de pénalisation permettant de limiter dans une certaine mesure le problème d’ambiguïté inhérent à la problématique «around-the-corner».Dans un deuxième temps, nous avons développé deux filtres particulaires pour pister une cible en milieu urbain en présence de multi-trajets. Ces algorithmes ont été appliqués aux données réelles issues d’une expérimentation et ont montré des résultats prometteurs : même avec une connaissance approximative de la géométrie de la scène, il a été possible de détecter, localiser et suivre une cible en exploitant uniquement l’information fournie par les retards des multi-trajets.
Published: 2018

25. Atomic scale analyses of {\bb Z}-module defects in an NiZr alloy

Author: Abdullah Sirindil, Frédéric Mompiou, Raphael Kobold, Loïc Perrière, Denis Gratias, Gilles Patriarche, Sylvie Lartigue-Korinek, Marianne Quiquandon, Ecole Nationale Supérieure de Chimie de Paris- Chimie ParisTech-PSL (ENSCP), Physique de la Plasticité et Métallurgie (CEMES-PPM), Centre d'élaboration de matériaux et d'études structurales (CEMES), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie et des Matériaux Paris Est, UMR 7182 Université Paris 12 et CNRS, Institut de Chimie et des Matériaux Paris-Est (ICMPE), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12), Laboratoire de photonique et de nanostructures (LPN), Centre National de la Recherche Scientifique (CNRS), Laboratoire d'étude des microstructures [Châtillon] (LEM - ONERA - CNRS), Université Paris Saclay (COmUE)-ONERA-Centre National de la Recherche Scientifique (CNRS), Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), Institut de Chimie du CNRS (INC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-ONERA, Institut de Recherche de Chimie Paris (IRCP), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Ministère de la Culture (MC), Institut National des Sciences Appliquées (INSA)-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées (INSA)-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), ONERA-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Ministère de la Culture (MC), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), and Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Materials science, Intermetallic, HREM-HAADF, 02 engineering and technology, 010403 inorganic & nuclear chemistry, 01 natural sciences, Biochemistry, Atomic units, law.invention, [SPI.MAT]Engineering Sciences [physics]/Materials, Inorganic Chemistry, [PHYS.MECA.MEMA]Physics [physics]/Mechanics [physics]/Mechanics of materials [physics.class-ph], Structural Biology, law, Lattice (order), Scanning transmission electron microscopy, [CHIM]Chemical Sciences, General Materials Science, Physical and Theoretical Chemistry, defects, ComputingMilieux_MISCELLANEOUS, Condensed matter physics, Quasicrystal, twins, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Research Papers, 0104 chemical sciences, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Orthorhombic crystal system, sense organs, {\bb Z}-module, Electron microscope, 0210 nano-technology, Monoclinic crystal system, dislocations
Abstract: This article describes the observation and determination of -module defects (twins, translation faults and module dislocations) in NiZr by high-resolution electron microscopy (HREM), and scanning transmission electron microscopy bright-field (STEM-BF) and high-angle annular dark-field (STEM-HAADF)., Some specific structures of intermetallic alloys, like approximants of quasicrystals, have their unit cells and most of their atoms located on a periodic fraction of the nodes of a unique -module [a set of the irrational projections of the nodes of a (N > 3-dimensional) lattice]. Those hidden internal symmetries generate possible new kinds of defects like coherent twins, translation defects and so-called module dislocations that have already been discussed elsewhere [Quiquandon et al. (2016 ▸). Acta Cryst. A72, 55–61; Sirindil et al. (2017 ▸). Acta Cryst. A73, 427–437]. Presented here are electron microscopy observations of the orthorhombic phase NiZr – and its low-temperature monoclinic variant – which reveal the existence of such defects based on the underlying -module generated by the five vertices of the regular pentagon. New high-resolution electron microscopy (HREM) and scanning transmission electron microscopy high-angle annular dark-field (STEM-HAADF) observations demonstrate the agreement between the geometrical description of the structure in five dimensions and the experimental observations of fivefold twins and translation defects.
Published: 2018
Full Text: View/download PDF

26. Landing Gear Interwheel Tonal Noise Characterization with the Boundary Element Method

Author: Antoine Hajczak, Philippe Druault, Laurent Sanders, DAAA, ONERA, Université Paris-Saclay (COmUE) [Châtillon], Université Paris Saclay (COmUE)-ONERA, Institut Jean Le Rond d'Alembert (DALEMBERT), and Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Landing gear, Acoustics and Ultrasonics, Mechanical Engineering, Acoustics, Rotational symmetry, tonal noise, 02 engineering and technology, Condensed Matter Physics, 01 natural sciences, Directivity, boundary element method, [PHYS.MECA.ACOU]Physics [physics]/Mechanics [physics]/Acoustics [physics.class-ph], Noise, Axle, 020303 mechanical engineering & transports, 0203 mechanical engineering, Mechanics of Materials, 0103 physical sciences, Aeroacoustics, aeroacoustics, 010301 acoustics, Boundary element method, Parametric statistics
Abstract: International audience; Landing gear noise is mainly broadband in nature, but it can also feature some tonal contributions. Tonal noise significantly increases noise annoyance and can originate from facing cavities in landing gear wheels. The present work aims at using the Boundary Element Method (BEM) with a simple harmonic point source model to characterize the resonance between the two facing cylindrical cavities in the wheels of the generic nose landing gear LAGOON, where a flow independence of the tonal noise emission has been reported experimentally. Three configurations of increasing complexity are successively considered: a single wheel, the two facing wheels linked by an axle, and finally the whole landing gear, including the main strut. In terms of resonant frequencies, the BEM is shown to give results in very good agreement with analytical formulae and CFD/CAA computations from the literature. Some acoustic measurements are also performed for the whole LAGOON configuration and a very good agreement is observed between BEM results and the experimental database. The directivity of the resonant modes is detailed for each case and compared with success to CFD/CAA results, except for convective amplification effects. The amplification of each resonant mode is quantified through a so-called scattering factor and it is shown that the facing cavities present much sharper resonances than the single cavity, and that the presence of the main strut only increases the amplification of the axisymmetric mode. Finally, the modelisation of the interwheel space by an annular duct is discussed and a parametric study is conducted on the axle diameter. The results of this parametric study shed light on the annular duct model domain of validity while demonstrating the ability of the BEM to treat geometries of arbitrary complexity with low computational cost when analytical models are unavailable.
Published: 2018
Full Text: View/download PDF

27. Adaptive optics pre-compensation for GEO feeder links: the FEEDELIO experiment

Author: C. B. Lim, Jean-Marc Conan, A. Montmerle Bonnefois, C. Petit, J. Montri, Bruno Fleury, Serge Meimon, N. Védrenne, F. Mendez, V. Michau, P. Perrault, DOTA, ONERA, Université Paris Saclay (COmUE) [Châtillon], ONERA-Université Paris Saclay (COmUE), Université Paris Saclay (COmUE)-ONERA, DOTA, ONERA, Université Paris Saclay [Châtillon], and ONERA-Université Paris-Saclay
Subjects: [PHYS]Physics [physics], Scintillation, [PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], business.industry, Computer science, 020206 networking & telecommunications, 02 engineering and technology, 7. Clean energy, 01 natural sciences, Compensation (engineering), Power (physics), 010309 optics, 0103 physical sciences, Path (graph theory), 0202 electrical engineering, electronic engineering, information engineering, [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, Stage (hydrology), Aerospace engineering, business, Adaptive optics, Throughput (business), Atmospheric optics, ComputingMilieux_MISCELLANEOUS
Abstract: Adaptive-Optics (AO) pre-compensation of atmospheric turbulence effects is one of the most promising technologies for achieving very high throughput optical GEO feeder links. However, its great performance has been proven mostly through numerical simulations until now, and experimental work on the subject is still at a very preliminary stage [1]. The FEEDELIO experiment (FEEDELIO for FEEDEr Link adaptive Optics), contracted to ONERA by ESA and described in this paper, goes one step further towards an experimental validation of this concept. This paper describes the experimental implementation of an AO pre-compensated link on a 13 km slant path in Tenerife, Canary Islands. This experiment is designed to be representative of a GEO feeder link, and aims at demonstrating a significant increase of the mean received power and decrease of the power fluctuations thanks to AO. It will also allow to study the impact of the point-ahead angle on overall performance of the AO system. The FEEDELIO experiment is planned for spring 2019.
Published: 2018
Full Text: View/download PDF

28. Simulation de la signature infrarouge des phénomènes lumineux transitoires en moyenne atmosphère

Author: Romand, Frédéric, DOTA, ONERA, Université Paris Saclay (COmUE) [Palaiseau], Université Paris Saclay (COmUE)-ONERA, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Sorbonne Université, and Sébastien Payan
Subjects: Plasma chemistry, [PHYS.MECA.VIBR]Physics [physics]/Mechanics [physics]/Vibrations [physics.class-ph], Chimie plasma, Atmospheric radiative transfer, Chimie vibrationnelle, Phénomènes lumineux transitoires, Atmosphere luminous events, Vibrational chemistry, Transfert radiatif atmosphérique, Sprites, Rayonnement infrarouge, Infrared radiation
Abstract: Even if it hasn’t been observed yet, the existence of emissions in the middle and far infrared following a sprite is suspected and could be related to vibrational excitation of CO2. In atmospheric sciences, the chemical composition can be retrieved through different remote sensing methods. For the Defense, natural infrared emissions could cause false alarms through airborne and spaceborne optronic detection systems. That is why it is necessary to characterize the infrared emissions of sprites. To do so, a plasma-vibrational kinetic model has been developed and coupled to an atmospheric radiative transfer model. This model allows evaluating the energetic and chemical effects following the electrical perturbation caused by the propagation of streamers, main constituent elements of sprites. The evaluated signatures could be detectable for an observer situated in the stratosphere or in space. Otherwise, the effects of the uncertainties on the principal parameters of the model have been quantified through a sensitivity analysis. Finally, this work allowed defining instrumental specifications for the future mission HALESIS (High Altitude Luminous Events Studied by Infrared Spectro-imagery), which will record hyperspectral infrared images of sprites and other middle atmosphere luminous events.; Encore jamais été observé, le rayonnement infrarouge moyen et lointain consécutif aux sprites a été prédit et serait lié à l’excitation des états vibrationnels de CO2. En sciences de l’atmosphère, la composition chimique peut être retrouvée par des méthodes de télédétection infrarouge. Pour la Défense, les émissions infrarouges naturelles peuvent causer de fausses alarmes à travers les systèmes de veille optronique satellitaires ou aéroportés. C’est pourquoi il est nécessaire de caractériser les émissions infrarouges des sprites. Pour cela, un modèle de cinétique plasma-vibrationnelle a été développé et couplé à un modèle de transfert radiatif atmosphérique. Celui-ci permet de simuler les effets énergétiques et chimiques consécutifs à la perturbation électrique des streamers, éléments constitutifs des sprites. Les signatures infrarouges évaluées devraient être détectables pour un observateur situé dans la stratosphère ou dans l’espace. Par ailleurs, les effets des incertitudes sur les principaux paramètres du modèle ont été quantifiés à travers une étude de sensibilité. Enfin, ces travaux ont permis de définir certaines spécifications instrumentales pour la mission HALESIS (High Altitude Luminous Events Studied by Infrared Spectro-imagery), qui aura pour but d’observer les sprites et autres phénomènes lumineux de moyenne atmosphère dans l’infrarouge.
Published: 2018

29. Development of ZDES method based on two-equation turbulence and turbomachinery application

Author: Uribe, Cédric, ONERA, Université Paris Saclay (COmUE) [Meudon], Université Paris Saclay (COmUE)-ONERA, Sorbonne Université, Georges Gerolymos, Julien Marty, and André, Cécile
Subjects: Zonal detached eddy simulation, Hybrid RANS/LES method, Turbulence modelling, Turbomachinery, Turbomachines, Simulation numérique, Validation, Modélisation de la turbulence, Numerical simulation, [PHYS.MECA]Physics [physics]/Mechanics [physics], [PHYS.MECA] Physics [physics]/Mechanics [physics], Approche hybride RANS/LES
Abstract: Accurate secondary and transitional ﬂows predictions are essential to turbomachinery improvements. They cause additional losses and operating domain reduction. For example tip-leakage vortex ﬂow or corner separation ﬂow in H.P. compressor lead to total pressure losses and promote axial instabilities (surge). Various laminar-turbulent transition processes regulate turbine blade thermal load and thus turbine blades life. Usual CFD turbulence modellings (RANS method) fail to cope with such strongly ﬂuctuating, separated and transitional ﬂows. In response to these challenges, one solution relies in the hybrid RANS/LES method called ZDES (Zonal Detached Eddy Simulation (Deck 2012)) in its operating modes 0, 1 and 2 : boundary layers are modelled following a RANS method in their whole thickness for avoiding their expensive resolution following an LES method (resolution of the large turbulence scales) which is only used - if needed - far from the wall for high ﬁdelity prediction of separated ﬂows thanks to continuous RANS/LES interfaces. In view to allow ZDES method to be compatible with the majority of laminar-turbulent transition models applied for internal ﬂows, this work proposes numerous ZDES’s variants no more based on Spalart et Allmaras turbulence model (ZDES SA method) but on Menter k − ω SST turbulence model (ZDES SST method). With regards to a deconstruction of their performances in major issues, this work demonstrates the behavioral similarity of those two methods on common ﬂow test cases (mixing layer, backward-facing step, circular cylinder) undemanding for their underlying turbulence model in RANS regions. This work also demonstrates the advantage of ZDES SST over ZDES SA for an industrial relevant test case (high-pressure axial compressor rotor) much more demanding. It assesses various ways of improvement for ZDES method. Finally, it supplements this validation process with a new common test case (axisymetric hill) allowing to isolate the issue of turbulent boundary layer separation prediction in the absence of geometrical singularity., Aﬁn d’améliorer les caractéristiques d’une turbomachine, il est capital de prévoir correctement les écoulements secondaires et/ou transitionnels s’y développant. Ces écoulements peuvent être à l’origine de la réduction de ses performances et de son domaine de fonctionnement. À titre d’exemple la présence de tourbillons de jeu ou de décollements de coin sur les aubages de compresseur H.P. engendre des pertes de pression totale favorisant l’apparition d’instabilités axiales (pompage). Les multiples processus de transition laminaire-turbulent modulent la charge thermique subie par les aubes de turbine et conditionnent donc leur durée de vie. La nature généralement fortement instationnaire, décollée et transitionnelle de ces écoulements rend leur prévision délicate voire imprécise avec les modélisations de la turbulence utilisées en conception (approche RANS). En réponse à ces déﬁs une solution est l’approche hybride RANS/LES dite ZDES (Zonal Detached Eddy Simulation (Deck 2012)) dans ses modes de fonctionnement 0, 1 et 2 : les couches limites sont traitées par une approche RANS dans leur entière épaisseur aﬁn de s’y affranchir du coût excessif d’une approche LES (résolution des grandes échelles de la turbulence) qui est seulement utilisée - si nécessaire - sur le reste du domaine de calcul pour une prévision haute ﬁdélité des écoulements décollés, l’interface entre les deux approches étant continue. Aﬁn que cette approche soit compatible avec la majorité des modèles de transition laminaire-turbulent, en particulier en aérodynamique interne, ces travaux en proposent diverses variantes non plus basées sur le modèle de turbulence de Spalart et Allmaras (approche ZDES SA) mais sur le modèle k − ω SST de Menter (approche ZDES SST). Au regard d’une décomposition en problématiques majeures de leurs performances, ils démontrent la similitude comportementale de ces deux approches sur des cas d’écoulement génériques (couche de mélange, marche descendante, barreau cylindrique) peu exigeants vis-à-vis de leur modèle de turbulence sous-jacent au sein des régions RANS. Ils démontrent également l’avantage de la ZDES SST sur la ZDES SA sur un cas d’intérêt industriel (rotor de compresseur axial H.P.) autrement plus exigeant et évaluent diverses voies d’amélioration pour l’approche ZDES. Enﬁn ils enrichissent cette démarche d’évaluation d’un nouveau cas générique d’écoulement (bosse axisymétrique) permettant d’isoler la problématique de la prévision des décollements de couche limite turbulente en l’absence de singularité géométrique.
Published: 2018

30. Deep Depth from Defocus: how can defocus blur improve 3D estimation using dense neural networks?

Author: Carvalho, Marcela, Le Saux, Bertrand, Trouvé-Peloux, Pauline, Almansa, Andrés, Champagnat, Frédéric, DTIS, ONERA, Université Paris Saclay [Palaiseau], ONERA-Université Paris-Saclay, Université Paris Descartes - Paris 5 (UPD5), André, Cécile, DTIS, ONERA, Université Paris Saclay (COmUE) [Palaiseau], ONERA-Université Paris Saclay (COmUE), and Université Paris Saclay (COmUE)-ONERA
Subjects: [PHYS]Physics [physics], [SPI] Engineering Sciences [physics], DEPTH PREDICTION, SINGLE-IMAGE, DEPTH ESTIMATION, [MATH] Mathematics [math], ESTIMATION PROFONDEUR, [INFO] Computer Science [cs], [PHYS] Physics [physics], MONO-IMAGE, [SPI]Engineering Sciences [physics], [INFO]Computer Science [cs], PROFONDEUR PAR DEFOCALISATION, ADAPTATION DOMAINE, [MATH]Mathematics [math], DOMAIN ADAPTATION, DEPTH FROM DEFOCUS
Abstract: Depth estimation is of critical interest for scene understanding and accurate 3D reconstruction. Most recent approaches in depth estimation with deep learning exploit geometrical structures of standard sharp images to predict corresponding depth maps. However, cameras can also produce images with defocus blur depending on the depth of the objects and camera settings. Hence, these features may represent an important hint for learning to predict depth. In this paper, we propose a full system for single-image depth prediction in the wild using depth-from-defocus and neural networks. We carry out thorough experiments to test deep convolutional networks on real and simulated defocused images using a realistic model of blur variation with respect to depth. We also investigate the influence of blur on depth prediction observing model uncertainty with a Bayesian neural network approach. From these studies, we show that out-of-focus blur greatly improves the depth-prediction network performances. Furthermore, we transfer the ability learned on a synthetic, indoor dataset to real, indoor and outdoor images. For this purpose, we present a new dataset containing real all-focus and defocused images from a Digital Single-Lens Reflex (DSLR) camera, paired with ground truth depth maps obtained with an active 3D sensor for indoor scenes. The proposed approach is successfully validated on both this new dataset and standard ones as NYUv2 or Depth-in-the-Wild., L'estimation de la profondeur est d'un intérêt critique pour la compréhension de la scène et la reconstruction 3D précise. Les approches les plus récentes en matière d'estimation de profondeur avec l'apprentissage profond exploitent les structures géométriques des images nettes standard pour prédire les cartes de profondeur correspondantes. Toutefois, les caméras peuvent également produire des images avec un flou de défocalisation en fonction de la profondeur des objets et des paramètres de l'appareil photo. Par conséquent, ces caractéristiques peuvent représenter un indice important pour apprendre à prédire la profondeur. Dans cet article, nous proposons un système complet de prédiction de profondeur à image unique dans la nature en utilisant des réseaux neurones et le depth-from-defocus (DFD). Nous effectuons des expériences approfondies pour tester des réseaux convolutifs profonds sur des images défocalisées réelles et simulées en utilisant un modèle réaliste de variation du flou par rapport à la profondeur. Nous étudions également l'influence du flou sur la prédiction de la profondeur en observant l'incertitude du modèle avec une approche de réseau de neurones bayésien. À partir de ces études, nous montrons que le flou de défocalisation améliore considérablement les performances du réseau de prédiction de la profondeur. De plus, nous transférons la capacité apprise sur un ensemble de données d'intérieur synthétique vers des images réelles intérieures et extérieures. À cette fin, nous présentons un nouvel ensemble de données contenant des images réelles entièrement focalisées et défocalisées provenantes d’une caméra reflex numérique (DSLR) couplées à des cartes de profondeur obtenues avec un capteur 3D actif pour les scènes d’intérieur. L'approche proposée a été validée avec succès sur ce nouveau jeu de données et sur des nouvelles bases de données et standard tels que NYUv2 ou Depth-in-the-Wild.
Published: 2018

31. Beyond sentiments and opinions: exploring social media with appraisal categories

Author: Emmanuelle Kelodjoue, Valentina Dragos, Delphine Battistelli, DTIS, ONERA, Université Paris Saclay (COmUE) [Palaiseau], Université Paris Saclay (COmUE)-ONERA, Modèles, Dynamiques, Corpus (MoDyCo), Université Paris Nanterre (UPN)-Centre National de la Recherche Scientifique (CNRS), and ONERA-Université Paris Saclay (COmUE)
Subjects: BIG DATA, Big data, 02 engineering and technology, [INFO.INFO-AI]Computer Science [cs]/Artificial Intelligence [cs.AI], 0202 electrical engineering, electronic engineering, information engineering, Social media, Set (psychology), APPRAISAL THEORY, SOCIAL MEDIA, business.industry, OPINIONS, 05 social sciences, Sentiment analysis, Appraisal theory, Data science, Content analysis, DONNÉES SOCIALES, 020201 artificial intelligence & image processing, 0509 other social sciences, 050904 information & library sciences, Construct (philosophy), Psychology, Cyberspace, business, OPEN SOURCE, SENTIMENTS
Abstract: International audience; The digital era arrives with a whole set of disruptive technologies that creates both risk and opportunity for open sources analysis. Although the sheer quantity of online conversations makes social media a huge source of information, their analysis is still a challenging task and many of traditional methods and research methodologies for data mining are not fit for purpose. Social data mining revolves around subjective content analysis, which deals with the computational processing of texts conveying people’s evaluations, beliefs, attitudes and emotions. Opinion mining and sentiment analysis are the main paradigm of social media exploration and both concepts are often interchangeable. This paper investigates the use of appraisal categories to explore data gleaned for social media, going beyond the limitations of traditional sentiment and opinion-oriented approaches. Categories of appraisal are grounded on cognitive foundations of the appraisal theory, according to which people’s emotional response are based on their own evaluative judgments or appraisals of situations, events or objects. A formal model is developed to describe and explain the way language is used in the cyberspace to evaluate, express mood and subjective states, construct personal standpoints and manage interpersonal interactions and relationships. A general processing framework is implemented to illustrate how the model is used to analyze a collection of tweets related to extremist attitudes.
Published: 2018

32. Single-mode fiber coupling for satellite-to-ground telecommunication links corrected by adaptive optics

Author: Lim, C B, Petit, C., Saab, K., Fleury, B., Mendez, F., Montri, J., Védrenne, N., Michau, V., DOTA, ONERA, Université Paris Saclay [Châtillon], ONERA-Université Paris-Saclay, DOTA, ONERA, Université Paris Saclay (COmUE) [Châtillon], and Université Paris Saclay (COmUE)-ONERA
Subjects: telecommunication, [PHYS.PHYS]Physics [physics]/Physics [physics], single-mode fiber, coupling, satellite-to-ground, adaptive optics
Abstract: International audience; The need for high data rate communication systems has encouraged the development of new satellite-to-ground optical links using adaptive optics to compensate for atmospheric turbulence, while exploiting existing fiber components to limit their cost. Knowing the statistic distribution of the fading durations of the corrected flux coupled into a single-mode fiber is a cornerstone to design the optical transmission system (coding and interleaving protocols for example). Besides, results on such coupling efficiency statistics are not limited to the telecom applications and could be useful for astronomical applications, such as spectroscopy. In this context, an analytical model was developed at ONERA, along with a compact optical bench (LISA2), we integrated for experimental validation on the sky. Based on a previous study, an injection module was included to LISA2 to maximize the fiber-coupling and minimize the impact of static aberrations. The system integration along with the first results of its functional validation are presented.
Published: 2018

33. High loop rate adaptive optics flood illumination ophthalmoscope with structured illumination capability

Author: Pedro Mecê, C. Petit, Serge Meimon, Kate Grieve, Aurélie Bonnefois, Laurent M. Mugnier, Jose A. Sahel, Jessica Jarosz, Michel Paques, Elena Gofas-Salas, DOTA, ONERA, Université Paris Saclay (COmUE) [Palaiseau], Université Paris Saclay (COmUE)-ONERA, Institut de la Vision, Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut National de la Santé et de la Recherche Médicale (INSERM), Paris Adaptive-Optics for Retinal Imaging and Surgery (Paris Group), Quantel Medical, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts (CHNO), and The University of Pittsburgh School of Medicine (Department of Ophtalmology)
Subjects: Male, Optics and Photonics, IMAGE PROCESSING, Light, Image quality, Computer science, RETINAL NERVE FIBER LAYER, Structured illumination microscopy, Image processing, OPTIQUE ADAPTATIVE, 01 natural sciences, 010309 optics, 03 medical and health sciences, 0302 clinical medicine, Optics, OPHTALMIC OPTICS AND DEVICES, 0103 physical sciences, medicine, Humans, OPHTALMOLOGY, FUNCTIONAL MONITORING AND IMAGING, Electrical and Electronic Engineering, Adaptive optics, Engineering (miscellaneous), ACTIVE OR ADAPTIVE OPTICS, Retina, Pixel, Stray light, business.industry, Ophthalmoscopes, OPHTALMOLOGIE, EYE MOVEMENTS, Retinal Vessels, Equipment Design, eye diseases, Atomic and Molecular Physics, and Optics, medicine.anatomical_structure, STRAY LIGHT, Regional Blood Flow, Temporal resolution, 030221 ophthalmology & optometry, [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, Female, MEDICAL AND BIOLOGICAL IMAGING, business, IMAGE QUALITY, WAVE FRONT SENSING
Abstract: International audience; The design and performance of an adaptive optics flood illumination ophthalmoscope (AO-FIO) platform, based on eye motion and dynamic aberrations experimental analysis, are described. The system incorporates a custom-built real-time controller, enabling up to 70 Hz loop rate without jitter, and an AO-corrected illumination capable of projecting high-resolution features in the retina. Wide-field (2.7°×5.4°) and distortionless images from vessel walls, capillaries, and the lamina cribrosa are obtained with an enhanced contrast and signal-to-noise ratio, thanks to careful control of AO parameters. The high spatial and temporal resolution (image acquisition up to 200 Hz) performance achieved by this platform enables the visualization of vessel deformation and blood flow. This system opens up the prospect of a return to favor of flood illumination adaptive optics systems provided that its high pixel rate and structured illumination capabilities are exploited.; La conception et la performance de l’ophtalmoscope plein champ assisté par Optique Adaptative (OA), basés sur des analyses expérimentales des mouvements et aberrations oculaires, sont décrites. Le système est composé d’un calculateur en temps-réel qui permet d’atteindre une vitesse de boucle d’asservissement de 70Hz. Le système permet aussi la projection de motifs dans la rétine. Grâce au contrôle et la maîtrise d’un système d’Optique Adaptative, des images à grand champ (2.7x5.4°) sans distorsion des différentes régions de la rétine présentent une amélioration de contraste et de rapport signal sur bruit. La haute résolution spatio-temporelle permet également la visualisation des déformations vasculaire et du flux sanguin. Ce système ouvre des nouvelles perspectives en ophtalmoscopie plein-champ, qui pourrait s'imposer dans les années à venir à condition que sa haute résolution temporelle et sa capacité de projeter des motifs d’illumination soient exploitées.
Published: 2018
Full Text: View/download PDF

34. High loop rate adaptive optics flood illumination ophthalmoscope with structured illumination capability

Author: Gofas-Salas, Elena, Mecê, Pedro, Petit, Cyril, Jarosz, Jessica, Mugnier, Laurent, Montmerle Bonnefois, Aurélie, Grieve, Kate, Sahel, José-Alain, Paques, Michel, Meimon, Serge, DOTA, ONERA, Université Paris Saclay (COmUE) [Palaiseau], Université Paris Saclay (COmUE)-ONERA, Institut de la Vision, Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut National de la Santé et de la Recherche Médicale (INSERM), Paris Adaptive-Optics for Retinal Imaging and Surgery (Paris Group), Quantel Medical, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts (CHNO), and The University of Pittsburgh School of Medicine (Department of Ophtalmology)
Subjects: ACTIVE OR ADAPTIVE OPTICS, IMAGE PROCESSING, RETINAL NERVE FIBER LAYER, OPHTALMOLOGIE, EYE MOVEMENTS, OPTIQUE ADAPTATIVE, STRAY LIGHT, OPHTALMIC OPTICS AND DEVICES, [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, OPHTALMOLOGY, FUNCTIONAL MONITORING AND IMAGING, MEDICAL AND BIOLOGICAL IMAGING, IMAGE QUALITY, WAVE FRONT SENSING
Abstract: International audience; The design and performance of an adaptive optics flood illumination ophthalmoscope (AO-FIO) platform, based on eye motion and dynamic aberrations experimental analysis, are described. The system incorporates a custom-built real-time controller, enabling up to 70 Hz loop rate without jitter, and an AO-corrected illumination capable of projecting high-resolution features in the retina. Wide-field (2.7°×5.4°) and distortionless images from vessel walls, capillaries, and the lamina cribrosa are obtained with an enhanced contrast and signal-to-noise ratio, thanks to careful control of AO parameters. The high spatial and temporal resolution (image acquisition up to 200 Hz) performance achieved by this platform enables the visualization of vessel deformation and blood flow. This system opens up the prospect of a return to favor of flood illumination adaptive optics systems provided that its high pixel rate and structured illumination capabilities are exploited.; La conception et la performance de l’ophtalmoscope plein champ assisté par Optique Adaptative (OA), basés sur des analyses expérimentales des mouvements et aberrations oculaires, sont décrites. Le système est composé d’un calculateur en temps-réel qui permet d’atteindre une vitesse de boucle d’asservissement de 70Hz. Le système permet aussi la projection de motifs dans la rétine. Grâce au contrôle et la maîtrise d’un système d’Optique Adaptative, des images à grand champ (2.7x5.4°) sans distorsion des différentes régions de la rétine présentent une amélioration de contraste et de rapport signal sur bruit. La haute résolution spatio-temporelle permet également la visualisation des déformations vasculaire et du flux sanguin. Ce système ouvre des nouvelles perspectives en ophtalmoscopie plein-champ, qui pourrait s'imposer dans les années à venir à condition que sa haute résolution temporelle et sa capacité de projeter des motifs d’illumination soient exploitées.
Published: 2018
Full Text: View/download PDF

35. Estimation de profondeur mono-image par réseaux de neurones et flou de défocalisation

Author: Carvalho, Marcela, Le Saux, Bertrand, Trouvé, Pauline, Almansa, Andrés, Champagnat, Frédéric, DTIS, ONERA, Université Paris Saclay (COmUE) [Palaiseau], Université Paris Saclay (COmUE)-ONERA, Université Paris Descartes - Paris 5 (UPD5), André, Cécile, ONERA-Université Paris Saclay (COmUE), DTIS, ONERA, Université Paris Saclay [Palaiseau], and ONERA-Université Paris-Saclay
Subjects: ESTIMATION DE PROFONDEUR, [INFO.INFO-LO] Computer Science [cs]/Logic in Computer Science [cs.LO], DEEP LEARNING, [INFO.INFO-IT]Computer Science [cs]/Information Theory [cs.IT], APPRENTISSAGE PROFOND, REGRESSION, [INFO.INFO-LO]Computer Science [cs]/Logic in Computer Science [cs.LO], [INFO.INFO-IT] Computer Science [cs]/Information Theory [cs.IT], MACHINE LEARNING, PROFONDEUR PAR LE FLOU DE DEFOCALISATION, DFD, ESTIMATION DE LA PROFONDEUR, DEPTH FROM DEFOCUS
Abstract: International audience; L’estimation de la profondeur monoculaire à l’aide de réseaux de neurones profonds a atteint aujourd’hui d’excellentes performances. Cependant, il est difficile d’établir l’influence respective de l’architecture, de la fonction de coût et des conditions d’expérimentations sur ces résultats. Dans cet article, nous présentons une nouvelle architecture, appelée D3-Net, pour l’estimation de profondeur monoculaire. Cette architecture, simple à entraîner et ne reposant pas sur des modèles analytiques de la scène nous permet d’étudier l’influence de différentes fonctions de coûts (standards et proposées dans l’état de l’art) et différentes conditions expérimentales sur les performances d’estimation de profondeur. Cette étude nous a amené à choisir une fonction de coût correspondant à la norme L1, à laquelle on ajoute une fonction de coût adversaire lors qu’un grand nombre de données est disponible. Notre méthode atteint alors les performances de l’état de l’art sur la base NYUv2. De plus les approches d’estimation de profondeur par apprentissage exploitent uniquement les structures géométriques des scènes et ne prennent pas en compte un indice depuis longtemps utilisé pour l’estimation de profondeur : le flou de défocalisation. Nous présentons ici une analyse sur données simulées qui montre le gain en performance lorsque la base contient des images avec du flou de défocalisation. Nous étudions également l’influence du flou dans la prédiction de profondeur en observant l’incertitude du modèle avec une approche de réseau de neurones bayésienne.
Published: 2018

36. Maritime circular SAR processing issues: Antenna pattern veri- fication, sea-clutter analysis and ship image autofocus

Author: Cantalloube, Hubert, Pastoré-Guyonvarc’h, Laurette, Martineau, Philippe, Martinot-Lagarde, Joseph, Castet, Nicolas, Oriot, Hélène, DEMR, ONERA, Université Paris Saclay [Palaiseau], ONERA-Université Paris-Saclay, Renault Vehicles, DEMR, ONERA [Salon], ONERA, André, Cécile, DEMR, ONERA, Université Paris Saclay (COmUE) [Palaiseau], and Université Paris Saclay (COmUE)-ONERA
Subjects: [PHYS]Physics [physics], [SPI]Engineering Sciences [physics], [SPI] Engineering Sciences [physics], RADAR IMAGING, CIRCULAR SYNTHETIC, [PHYS] Physics [physics], SAR
Abstract: International audience; During two SAR acquisition campaigns in 2015 and 2017, several circular SAR acquisitions have been performed on sea surface and ships. The 2015 set is full polarimetric acquisition at both X & L band (8 channels with 300 & 150 MHz bandwidth each). The 2017 set is vertical polarisation at X band (two channels with 2 GHz bandwidth each). Several processing issues had to be addressed with these experiments: - Simultaneous antenna pattern & sea clutter backscatter table evaluation was required because of antenna pattern compensation abnomalies at X band. - The autofocus used above ground was useless on the moving sea surface, hence the ships images required autofocus with tiepoints on the ship itself to compensate her own motion. During the 2017 campaign, low resolution images were synthesised on board to assess correct target acquisition during flight.
Published: 2018

37. Countering illegal UAV flights : passive DVB radar potentiality

Author: Dominique Poullin, DEMR, ONERA, Université Paris Saclay (COmUE) [Palaiseau], and Université Paris Saclay (COmUE)-ONERA
Subjects: [PHYS]Physics [physics], RADAR DETECTION, BIRDS, Computer science, 010401 analytical chemistry, Real-time computing, Active systems, Radar detection, DIGITAL VIDEO BROADCASTING, 01 natural sciences, 0104 chemical sciences, law.invention, Passive radar, System requirements, [SPI]Engineering Sciences [physics], Identification (information), law, Component (UML), SURVEILLANCE, Digital Video Broadcasting, TARGET TRACKING, MODULATION, Radar
Abstract: International audience; Since a few years, illegal UAV(Unmanned Aerial Vehicle) flights have been observed in different countries and under various environments[1]. Following these malicious fligths, most of the countries decided to counter such illegal activities asking their main industrial and laboratories to provide an already existing global solution against such UAV activities. However, it seems that up to now, none active system has been validated as the universal ideal solution. This paper will analyse the main system requirements. Then the potential of a passive DVB-T (Digital Video Broadcasting- Terrestrial) component will be illustrated using experimental data for both the detection, identification, location and alert functions:•The expected benefits of such a passive DVB-T solution will be analysed by considering experimental results on multi-rotors UAV as well as on fixed wings UAV.•Furthermore, some limitations of such a passive countering UAV component/system will be outlined.In summary, the passive DVB-T component offers very attractive capabilities for struggling against UAV at ranges up to three kilometres and even more in terms of detection, identification, location and alert.The interest of passive component for struggling against UAV is quite new [2] and it has to be noticed that several papers were dedicated to such an application during the last Passive Coherent Location Meeting in Bonn Wachtberg in 2017[3][4][5].
Published: 2018
Full Text: View/download PDF

38. Imagerie SAR haute résolution aéroportée

Author: Oriot, Hélène, DEMR, ONERA, Université Paris Saclay (COmUE) [Palaiseau], Université Paris Saclay (COmUE)-ONERA, UNIVERSITE DE PARIS-SUD CENTRE D'ORSAY, and Sylvie MARCOS
Subjects: [PHYS]Physics [physics], SYSTEME RADAR, IMAGERIE SAR, INTERFEROMETRIE, DETECTION CIBLE MOBILE, SAR PROCESSING, AEROPORTEE, SAR IMAGERY, RADAR, INTERFEROMETRY, [SPI]Engineering Sciences [physics], RADAR SYSTEM, GMTI, AIRBORNE SENSOR
Abstract: With the growing number of operating spatial systems, SAR imagery has become a major topic of research in the remote sensing community. In France, most of the research focuses on the exploitation of satellite SAR images. On the contrary, given the lower availability of such data, the airborne domain concerns a smaller community. This report aims at presenting the specificities of high-resolution airborne radar imagery and their impacts on multi-channel applications.A first part is devoted to a theoretical analysis of airborne SAR processing in its different modalities. The various SAR processing approaches adapted to high resolution are presented from a geometric point of view rather than frequential point of view. Then, the principles of multichannel processing are presented with emphasis on the phenomenology associated with the improvement of the resolution: link between image registration and interferometric phase, behavior of point like scatterers, anisotropic or surfacic backscatters. A second part is dedicated to the impact of real acquisition systems on SAR processing and multichannel applications. Issues related to the radar hardware, the antenna particularities, non-linearities of the trajectories are discussed and illustrated on applications such as calibration of polarimetric data, 3D extraction, ground moving target detection .; Avec la multiplication des systèmes spatiaux, l’imagerie radar fait l’objet de nombreux travaux de recherche. En France, la majorité des travaux se concentre sur l’exploitation des images radar spatiales, de résolution de plus en plus fine. Le domaine aéroporté concerne une communauté plus restreinte étant donnée la moindre disponibilité de telles données. Ce rapport a pour vocation de présenter les spécificités de l’imagerie radar aéroportée haute résolution et d’en comprendre les impacts sur les applications multi-voies.Une première partie est consacrée à l’analyse théorique du traitement SAR aéroporté dans ses différentes modalités. Les diverses approches de traitement SAR adaptés à la haute résolution sont présentées selon un point de vue géométrique plutôt que fréquentiel. Puis, toujours sous ce même angle, les principes des traitements multivoies sont abordés en insistant sur les phénomènes apparaissant avec l’amélioration de la résolution : lien entre recalage d’images et phase interférométrique, comportement des rétrodiffuseurs ponctuels, surfaciques et anisotropes.Une deuxième partie est consacrée à l’étude de l’impact d’un système réel d’acquisition sur le traitement SAR et les applications multivoies. Les problématiques liées à la chaîne radar, aux diagrammes d’antennes, aux trajectoires non linéaires sont abordées.Enfin, différents travaux d’exploitation d’images radar haute résolution aéroportées (calibration de données polarimétriques, extraction du 3D sur les images SAR, détection de cibles mobiles) illustrent le propos.
Published: 2018

39. Texture Super Resolution for 3D Reconstruction

Author: Burns, Calum, DEMR, ONERA, Université Paris Saclay (COmUE) [Palaiseau], Université Paris Saclay (COmUE)-ONERA, Université Paris-Saclay, Frédéric Champagnat, and STAR, ABES
Subjects: Super résolution, [INFO.INFO-TS]Computer Science [cs]/Signal and Image Processing, [INFO.INFO-TS] Computer Science [cs]/Signal and Image Processing, Texture mapping, Reconstruction 3D, Texture, 3D Reconstruction, Super resolution
Abstract: Multi-view 3D reconstruction techniques have reached industrial level maturity : non-expert users are now able to use commercial software to produce quality, large scale, 3D models. These reconstructions use top of the line sensors such as LIDAR or DSLR cameras, mounted on tripods and moved around the scene. Such protocols are not designed to efficiently inspect large infrastructures with complex geometry. As the capabilities of micro-drones progress at a fast rate, it is becoming possible to delegate such tasks to them. This choice induces changes in the acquired data : rather than a set of carefully acquired images, micro-drones will produce a video sequence with varying image quality, due to such flaws as motion blur and defocus. Processing video data is challenging for photogrammetry software, due to the high combinatorial cost induced by the large number of images. We use the full image sequence in two steps. Firstly, a 3D reconstruction is obtained using a temporal sub-sampling of the data, then a high resolution texture is built from the full sequence. Texture allows the inspector to visualize small details that may be lost in the noise of the geometric reconstruction. We apply Super Resolution techniques to achieve texture quality augmentation. To reach this goal we developed an algorithmic pipeline that processes the video input and outputs a 3D model of the scene with super resolved texture. This pipeline uses a state of the art 3D reconstruction software for the geometric reconstruction step. The main contribution of this pipeline is the image registration method used to achieve the sub-pixel accuracy required for Super Resolution. Unlike the data on which Super Resolution is generally applied, our viewpoints are subject to relative 3D motion and are facing a scene with 3D geometry, which makes the motion field all the more complex. The intrinsic precision of current 3D reconstruction algorithms is insufficient to perform a purely geometric registration. Instead we refine the geometric registration with an optical flow algorithm. This approach is qualitatively to a competing state of the art method. qualitative comparisons are reinforced by a quantitative evaluation of the resulting image quality. For this we developed a quantitative evaluation protocol of Super Resolution techniques applied to 3D surfaces. This method is based on the Binary Fractal Targets proposed by S. Landeau. We extended these ideas to the context of curved surfaces. This method has been used to validate our choice of Super Resolution algorithm. Finally, specularities present on the scene surfaces induce artefacts in our Super Resolution results, due to the loss of photoconsistency among the set of images to be fused. To address this problem we propose two corrective methods designed to achieve photometric registration of our images and restore photoconsistency. The first method is based on a model of the illumination phenomena, valid in a specific setting, the second relies on local photometric equalization among the images. When tested on data polluted by varying illumination, both methods were able to eliminate these artefacts., La reconstruction 3D multi-vue atteint désormais un niveau de maturité industrielle : des utilisateurs non-experts peuvent produire des modèles 3D large-échelle de qualité à l'aide de logiciels commerciaux. Ces reconstructions utilisent des capteurs haut de gamme comme des LIDAR ou des appareils photos de type DSLR, montés sur un trépied et déplacés autour de la scène. Ces protocoles d'acquisition sont mal adaptés à l’inspection d’infrastructures de grande taille, à géométrie complexe. Avec l'évolution rapide des capacités des micro-drones, il devient envisageable de leur confier ce type de tâche. Un tel choix modifie les données d’acquisition : on passe d’un ensemble restreint de photos de qualité, soigneusement acquises par l’opérateur, à une séquence d'images à cadence vidéo, sujette à des variations de qualité image dues, par exemple, au bougé et au défocus.Les données vidéo posent problème aux logiciels de photogrammétrie du fait de la combinatoire élevée engendrée par le grand nombre d’images. Nous proposons d’exploiter l’intégralité des images en deux étapes. Au cours de la première, la reconstruction 3D est obtenue en sous-échantillonnant temporellement la séquence, lors de la seconde, la restitution haute résolution de texture est obtenue en exploitant l'ensemble des images. L'intérêt de la texture est de permettre de visualiser des détails fins du modèle numérisé qui ont été perdus dans le bruit géométrique de la reconstruction. Cette augmentation de qualité se fait via des techniques de Super Résolution (SR).Pour atteindre cet objectif nous avons conçu et réalisé une chaîne algorithmique prenant, en entrée, la séquence vidéo acquise et fournissant, en sortie, un modèle 3D de la scène avec une texture sur-résolue. Cette chaîne est construite autour d’un algorithme de reconstruction 3D multi-vues de l’état de l’art pour la partie géométrique.Une contribution centrale de notre chaîne est la méthode de recalage employée afin d’atteindre la précision sub-pixellique requise pour la SR. Contrairement aux données classiquement utilisées en SR, nos prises de vues sont affectées par un mouvement 3D, face à une scène à géométrie 3D, ce qui entraîne des mouvements image complexes. La précision intrinsèque des méthodes de reconstruction 3D est insuffisante pour effectuer un recalage purement géométrique, ainsi nous appliquons un raffinement supplémentaire par flot optique. Le résultat de cette méthode de restitution de texture SR est d'abord comparée qualitativement à une approche concurrente de l’état de l’art.Ces appréciations qualitatives sont renforcées par une évaluation quantitative de qualité image. Nous avons à cet effet élaboré un protocole d’évaluation quantitatif de techniques de SR appliquées sur des surfaces 3D. Il est fondé sur l'utilisation de mires fractales binaires, initialement proposées par S. Landeau. Nous avons étendu ces idées au contexte de SR sur des surfaces courbes. Cette méthode est employée ici pour valider les choix de notre méthode de SR, mais elle s'applique à l'évaluation de toute texturation de modèle 3D.Enfin, les surfaces spéculaires présentes dans les scènes induisent des artefacts au niveau des résultats de SR en raison de la perte de photoconsistence des pixels au travers des images à fusionner. Pour traiter ce problème nous avons proposé deux méthodes correctives permettant de recaler photométriquement nos images et restaurer la photoconsistence. La première méthode est basée sur une modélisation des phénomènes d’illumination dans un cas d'usage particulier, la seconde repose sur une égalisation photométrique locale. Les deux méthodes testées sur des données polluées par une illumination variable s'avèrent effectivement capables d'éliminer les artefacts.
Published: 2018

40. Multifunctional Ti–Me (Me=Al, Cu) thin film systems for biomedical sensing devices

Author: Filipe Vaz, C. Lopes, M. Vieira, M. Apreutesei, Luís Miguel Cunha, Joel Nuno Pinto Borges, J P Fernandes, N.P. Barradas, Philippe Steyer, Eduardo Alves, Marcos Rodrigues, Carlos J. Tavares, Universidade do Porto, Instituto Superior de Engenharia de Lisboa (ISEL), Centre of Technology and Systems (CTS), Faculdade de Ciências e Tecnologia = School of Science & Technology (FCT NOVA), Universidade Nova de Lisboa = NOVA University Lisbon (NOVA)-Universidade Nova de Lisboa = NOVA University Lisbon (NOVA), Centre de recherche du CHUM (CR), CHUM-Hôpital Notre-Dame, Instituto de Plasmas e Fusão Nuclear [Lisboa] (IPFN), Instituto Superior Técnico, Universidade Técnica de Lisboa (IST), Instituto Tecnológico e Nuclear (ITN), ITN, CFNUL, Matériaux, ingénierie et science [Villeurbanne] (MATEIS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Universidade do Minho, Departamento de Física [Minho] (DFUM), ONERA - The French Aerospace Lab [Châtillon], Université Paris Saclay (COmUE)-ONERA, and Instituto Nacional de Pesquisas da Amazônia (INPA)
Subjects: Atoms, Engineering, Metastable phases, Intermetallics, Thin film systems, Ciências Naturais::Ciências Físicas, Electric properties, Thin films, Ciências Físicas [Ciências Naturais], Nanotechnology, Discharge characteristics, 02 engineering and technology, European Social Fund, 01 natural sciences, [SPI.MAT]Engineering Sciences [physics]/Materials, Intermetallic phasis, 0103 physical sciences, Intermetallic systems, Resistivity values, [CHIM]Chemical Sciences, Instrumentation, ComputingMilieux_MISCELLANEOUS, Metallic films, 010302 applied physics, Science & Technology, business.industry, Ti-Me thin films, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Structural characterization, Engineering physics, Binary intermetallics, Sensing devices, Quality enhancement, Surfaces, Coatings and Films, 13. Climate action, Intermetallic compounds, Technical university, Electrical properties, Biomedical sensing devices, 0210 nano-technology, business, Copper, Aluminum
Abstract: Ti-Me binary intermetallic thin films based on a titanium matrix doped with increasing amounts of Me (Me = Al, Cu) were prepared by magnetron sputtering (under similar conditions), aiming their application in biomedical sensing devices. The differences observed on the composition and on the micro(structural) features of the films, attributed to changes in the discharge characteristics, were correlated with the electrical properties of the intermetallic systems (Ti-Al and Ti-Cu). For the same Me exposed areas placed on the Ti target (ranging from 0.25 cm2 to 20 cm2) the Cu content increased from 3.5 at.% to 71.7 at.% in the Ti-Cu system and the Al content, in Ti-Al films, ranged from 11 to 45 at.%. The structural characterization evidenced the formation of metastable Ti-Me intermetallic phases for Al/Ti atomic ratios above 0.20 and for Cu/Ti ratios above 0.25. For lower Me concentrations, the effect of the α-Ti(Me) structure domains the overall structure. With the increase amount of the Me into Ti structure a clear trend for amorphization was observed. For both systems it was observed a significant decrease of the electrical resistivity with increasing Me/Ti atomic ratios (higher than 0.5 for Al/Ti atomic ratio and higher than 1.3 for Cu/Ti atomic ratio). Although similar trends were observed in the resistivity evolution for both systems, the Ti-Cu films presented lower resistivity values in comparison to Ti-Al system., Operacional Factores de Competitividade – and by national funds through FCT – Fundação para a Ciência e a Tecnologia –, under the projects PEST-C/FIS/UI607/2013 and PEst-C/EME/UI0285/2013. J. Borges also acknowledges the support by the European social fund within the framework of realizing the project “Support of inter-sectoral mobility and quality enhancement of research teams at Czech Technical University in Prague”, CZ.1.07/2.3.00/30.0034.
Published: 2015
Full Text: View/download PDF

41. Uneven-order decentered Shapiro filters for boundary filtering

Author: Fabrice Falissard, ONERA - The French Aerospace Lab [Châtillon], ONERA-Université Paris Saclay (COmUE), and Université Paris Saclay (COmUE)-ONERA
Subjects: Physics and Astronomy (miscellaneous), WEATHER FORECASTING, Computation, DECENTERING, Boundary (topology), Geometry, 01 natural sciences, 010305 fluids & plasmas, Physics::Popular Physics, symbols.namesake, 0103 physical sciences, 0101 mathematics, AERODYNAMICS, SPATIAL FILTER, Mathematics, [SPI.ACOU]Engineering Sciences [physics]/Acoustics [physics.class-ph], Numerical Analysis, Spatial filter, Applied Mathematics, Mathematical analysis, HIGH-ORDER, Order (ring theory), AEROACOUSTICS, Aerodynamics, Computer Science Applications, Euler equations, 010101 applied mathematics, Computational Mathematics, BOUNDARY, TheoryofComputation_MATHEMATICALLOGICANDFORMALLANGUAGES, Modeling and Simulation, Compressibility, symbols, Aeroacoustics, Computer Science::Formal Languages and Automata Theory
Abstract: International audience; This paper addresses the use of Shapiro filters for boundary filtering. A new class of uneven-order decentered Shapiro filters is proposed and compared to classical Shapiro filters and even-order decentered Shapiro filters. The theoretical analysis shows that the proposed boundary filters are more accurate than the centered Shapiro filters and more robust than the even-order decentered boundary filters usable at the same distance to the boundary. The benefit of the new boundary filters isassessed for computations using the compressible Euler equations.
Published: 2015
Full Text: View/download PDF

42. Psychological processes associated with insomnia in patients with multiple sclerosis

Author: Marie-Christine Gély-Nargeot, Clarisse Carra-Dalliere, Pierre Labauge, Jeanne Bernard, Vanessa Schellaert, Jean-Baptiste Blache, Sophie Bayard, Khaalid Hassan Maudarbocus, Cindy Lebrun, Xavier Ayrignac, Dynamique des capacités humaines et des conduites de santé (EPSYLON), Université de Montpellier (UM)-Université Paul-Valéry - Montpellier 3 (UPVM)-Université Montpellier 1 (UM1), Département de neurologie [Montpellier], Hôpital Gui de Chauliac [Montpellier]-Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier)-Université Montpellier 1 (UM1)-Université de Montpellier (UM), Université de Montpellier (UM), Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier), CHU Montpellier, Euromov (EuroMov), ONERA - The French Aerospace Lab [Châtillon], Université Paris Saclay (COmUE)-ONERA, Université Montpellier 1 (UM1)-Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier)-Hôpital Gui de Chauliac [Montpellier]-Université de Montpellier (UM), and Université Montpellier 1 (UM1)-Université Paul-Valéry - Montpellier 3 (UM3)-Université de Montpellier (UM)
Subjects: Adult, Male, Multiple Sclerosis, [SDV]Life Sciences [q-bio], media_common.quotation_subject, medicine.medical_treatment, Emotions, Neurological examination, Comorbidity, Neurological disorder, Anxiety, 03 medical and health sciences, 0302 clinical medicine, Sleep Initiation and Maintenance Disorders, Physiology (medical), mental disorders, medicine, Safety behaviors, Humans, 030212 general & internal medicine, ComputingMilieux_MISCELLANEOUS, media_common, medicine.diagnostic_test, business.industry, Cognition, Middle Aged, medicine.disease, nervous system diseases, 3. Good health, Cognitive behavioral therapy, Cross-Sectional Studies, [SCCO.PSYC]Cognitive science/Psychology, Female, Self Report, Neurology (clinical), Worry, medicine.symptom, Sleep, Arousal, business, 030217 neurology & neurosurgery, Clinical psychology
Abstract: International audience; Study Objectives: Despite the high comorbidity of insomnia disorder (ID) with multiple sclerosis (MS), the relevance of psychological processes involved in the maintenance of insomnia is yet to be established in this neurological disorder. This study aimed to ascertain to what extent the suggested emotional, cognitive, and behavioral processes maintaining insomnia are relevant in people with insomnia and MS. Methods: A between-subjects design was used to compare 26 patients with insomnia and MS, with 31 patients with MS only, and with 26 matched neurological disease-free individuals with insomnia. All patients participated in a standardized clinical interview and completed a battery of self-reported measures of cognitive and somatic presleep arousal experienced at bedtime, sleep- or insomnia-related unhelpful beliefs, and sleep-related safety behaviors. All patients with MS underwent a neurological examination. Results: ID comorbid to MS was strongly associated with increased levels of cognitive and somatic arousal, higher endorsement of dysfunctional beliefs about the consequences of insomnia on daytime functioning, and worry about insomnia and more frequent engagement in sleep-related safety behaviors. Patients with MS with ID did not differ from neurological disease-free individuals with insomnia on these measures. No link was found between MS clinical peculiarities and ID diagnosis. Conclusions: ID comorbid to MS is associated with the classical psychological factors perpetuating ID in neurological disease-free individuals with insomnia. Primary care providers and neurologists should consider target-oriented therapies like cognitive behavioral therapy for chronic insomnia as a treatment approach for ID comorbid to MS.
Published: 2018
Full Text: View/download PDF

43. Generative Adversarial Networks for Realistic Synthesis of Hyperspectral Samples

Author: Nicolas Audebert, Sébastien Lefèvre, Bertrand Le Saux, Environment observation with complex imagery ( OBELIX ), Université de Bretagne Sud ( UBS ) -SIGNAUX ET IMAGES NUMÉRIQUES, ROBOTIQUE ( IRISA-D5 ), Institut de Recherche en Informatique et Systèmes Aléatoires ( IRISA ), CentraleSupélec-Université de Rennes 1 ( UR1 ), Université de Rennes ( UNIV-RENNES ) -Université de Rennes ( UNIV-RENNES ) -Télécom Bretagne-Institut National des Sciences Appliquées ( INSA ) -Institut National de Recherche en Informatique et en Automatique ( Inria ) -École normale supérieure - Rennes ( ENS Rennes ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Bretagne Sud ( UBS ) -CentraleSupélec-Université de Rennes 1 ( UR1 ), Université de Rennes ( UNIV-RENNES ) -Université de Rennes ( UNIV-RENNES ) -Télécom Bretagne-Institut National des Sciences Appliquées ( INSA ) -Institut National de Recherche en Informatique et en Automatique ( Inria ) -École normale supérieure - Rennes ( ENS Rennes ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Bretagne Sud ( UBS ) -Institut de Recherche en Informatique et Systèmes Aléatoires ( IRISA ), Université de Rennes ( UNIV-RENNES ) -Université de Rennes ( UNIV-RENNES ) -Télécom Bretagne-Institut National des Sciences Appliquées ( INSA ) -Institut National de Recherche en Informatique et en Automatique ( Inria ) -École normale supérieure - Rennes ( ENS Rennes ) -Centre National de la Recherche Scientifique ( CNRS ), DTIS, ONERA, Université Paris Saclay ( DTIS, ONERA, Université Paris Saclay (F-91123 Palaiseau - France) ), ONERA-Université Paris-Saclay, Environment observation with complex imagery (OBELIX), Université de Bretagne Sud (UBS)-SIGNAUX ET IMAGES NUMÉRIQUES, ROBOTIQUE (IRISA-D5), Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), CentraleSupélec-Télécom Bretagne-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National de Recherche en Informatique et en Automatique (Inria)-École normale supérieure - Rennes (ENS Rennes)-Université de Bretagne Sud (UBS)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Télécom Bretagne-Université de Rennes 1 (UR1), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National de Recherche en Informatique et en Automatique (Inria)-École normale supérieure - Rennes (ENS Rennes)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), DTIS, ONERA, Université Paris Saclay (COmUE) [Palaiseau], Université Paris Saclay (COmUE)-ONERA, Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Université de Bretagne Sud (UBS)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-CentraleSupélec-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Université de Rennes (UNIV-RENNES)-CentraleSupélec-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-CentraleSupélec, DTIS, ONERA, Université Paris Saclay [Palaiseau], Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), and ONERA-Université Paris Saclay (COmUE)
Subjects: FOS: Computer and information sciences, generative models, Computer science, hyperspectral image classification, Computer Vision and Pattern Recognition (cs.CV), 0211 other engineering and technologies, Computer Science - Computer Vision and Pattern Recognition, 02 engineering and technology, [INFO.INFO-NE]Computer Science [cs]/Neural and Evolutionary Computing [cs.NE], 010501 environmental sciences, Machine learning, computer.software_genre, [ INFO.INFO-CV ] Computer Science [cs]/Computer Vision and Pattern Recognition [cs.CV], 01 natural sciences, Spectral line, Adversarial system, [ INFO.INFO-TI ] Computer Science [cs]/Image Processing, Neural and Evolutionary Computing (cs.NE), [ INFO.INFO-NE ] Computer Science [cs]/Neural and Evolutionary Computing [cs.NE], 021101 geological & geomatics engineering, 0105 earth and related environmental sciences, business.industry, Deep learning, [INFO.INFO-CV]Computer Science [cs]/Computer Vision and Pattern Recognition [cs.CV], Hyperspectral imaging, Computer Science - Neural and Evolutionary Computing, deep learning, ComputingMethodologies_PATTERNRECOGNITION, [INFO.INFO-TI]Computer Science [cs]/Image Processing [eess.IV], Artificial intelligence, business, computer, Generative grammar, Interpolation, data augmentation
Abstract: International audience; This work addresses the scarcity of annotated hyperspectral data required to train deep neural networks. Especially, we investigate generative adversarial networks and their application to the synthesis of consistent labeled spectra. By training such networks on public datasets, we show that these models are not only able to capture the underlying distribution, but also to generate genuine-looking and physically plausible spectra. Moreover, we experimentally validate that the synthetic samples can be used as an effective data augmentation strategy. We validate our approach on several public hyper-spectral datasets using a variety of deep classifiers.
Published: 2018
Full Text: View/download PDF

44. AMICal Sat and ATISE: two space missions for auroral monitoring

Author: Mathieu Barthelemy, Mikhail Stepanov, Mikhail Panasyuk, Thierry Sequies, Emmanuelle Aubert, Etienne Le Coarer, Erik Kerstel, Benedicte Escudier, Fabien Apper, Guillaume Bourdarot, Arnau Busom Vidal, Hacheme Ayasso, Vladimir Kalegaev, Laurence Croizé, Melanie Prugniaux, Vincent Grennerat, Frédéric Romand, Alexander Basaev, Etienne Rolland, Sébastien Payan, Anne Vialatte, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP), D.V. Skobeltsyn Institute of Nuclear Physics (SINP), Lomonosov Moscow State University (MSU), Laboratoire Interdisciplinaire de Physique [Saint Martin d’Hères] (LIPhy), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Joseph Fourier - Grenoble 1 (UJF), Scientific-Manufacturing Complex 'Technological Centre' (SMC TC), Université Grenoble Alpes (UGA), CICS (GIPSA-CICS), Département Images et Signal (GIPSA-DIS), Grenoble Images Parole Signal Automatique (GIPSA-lab), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Stendhal - Grenoble 3-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Stendhal - Grenoble 3-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Grenoble Images Parole Signal Automatique (GIPSA-lab), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Stendhal - Grenoble 3-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Stendhal - Grenoble 3-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), DOTA, ONERA, Université Paris Saclay [Palaiseau], ONERA-Université Paris-Saclay, TROPO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), GIPSA - Communication Information and Complex Systems (GIPSA-CICS), Grenoble Images Parole Signal Automatique (GIPSA-lab ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Grenoble Images Parole Signal Automatique (GIPSA-lab ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), DOTA, ONERA, Université Paris Saclay (COmUE) [Palaiseau], ONERA-Université Paris Saclay (COmUE), Université Paris Saclay (COmUE)-ONERA, and Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)
Subjects: Atmospheric Science, spectroscopy, 010504 meteorology & atmospheric sciences, space weather, Space weather, lcsh:QC851-999, 7. Clean energy, 01 natural sciences, Space exploration, 0103 physical sciences, CubeSat, airglow, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Remote sensing, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], Spectrometer, Detector, Airglow, Observable, aurora, visible, [PHYS.PHYS.PHYS-SPACE-PH]Physics [physics]/Physics [physics]/Space Physics [physics.space-ph], 13. Climate action, Space and Planetary Science, Environmental science, lcsh:Meteorology. Climatology, Ionosphere
Abstract: A lack of observable quantities renders it generally difficult to confront models of Space Weather with experimental data and drastically reduces the forecast accuracy. This is especially true for the region of Earth’s atmosphere between altitudes of 90 km and 300 km, which is practically inaccessible, except by means of remote sensing techniques. For this reason auroral emissions are an interesting proxy for the physical processes taking place in this region. This paper describes two future space missions, AMICal Sat and ATISE, that will rely on CubeSats to observe the aurora. These satellites will perform measurements of auroral emissions in order to reconstruct the deposition of particle precipitations in auroral regions. ATISE is a 12U CubeSat with a spectrometer and imager payloads. The spectrometer is built using the micro-Spectrometer-On-a-Chip (μSPOC) technology. It will work in the 370–900 nm wavelength range and allow for short exposure times of around 1 s. The spectrometer will have six lines of sight. The joint imager is a miniaturized wide-field imager based on the Teledyne-E2V ONYX detector in combination with a large aperture objective. Observation will be done at the limb and will enable reconstruction of the vertical profile of the auroral emissions. ATISE is planned to be launched in mid 2021. AMICal Sat is a 2U CubeSat that will embed the imager of ATISE and will observe the aurora both in limb and nadir configurations. This imager will enable measuring vertical profiles of the emission when observing in a limb configuration similar to that of ATISE. It will map a large part of the night side auroral oval with a resolution of the order of a few km. Both the spectrometer and imager will be calibrated with a photometric precision better than 10% using the moon as a wide-field, stable and extended source. Ground-based demonstrators of both instruments have been tested in 2017 in Norway and Svalbard. Even though some issues still need to be solved, the first results are very encouraging for the planned future space missions. Data interpretation will be done using the forward Transsolo code, a 1D kinetic code solving the Boltzmann equation along a local vertical and enabling simulation of the thermospheric and ionospheric emissions using precipitation data as input.
Published: 2018
Full Text: View/download PDF

45. The GJ 504 system revisited. Combining interferometric, radial velocity, and high contrast imaging data

Author: Lagrange, A. -M., Marleau, G. -D., Mollière, P., Orazi, V. D, Baudino, J. -L., Bartucci, A. Musso, Elwain, M. Mc, Beuzit, J. -L., Delboulbe, A., Bonnefoy, M., Perraut, K., Lagrange, M., Delorme, P., Vigan, Arthur, Line, M., Rodet, L., Ginski, C., Mourard, D., Marleau, D., Samland, M., Tremblin, P., Ligi, R., Cantalloube, F., Molliere, P., Charnay, B., Kuzuhara, M., Janson, M., Morley, C., Homeier, D. D., D’Orazi, V., Klahr, H., Mordasini, C., Lavie, B., Baudino, L., Beust, H., Peretti, S., Musso Bartucci, A., Mesa, D., Bézard, B., Boccaletti, A., Galicher, R., Hagelberg, J., Desidera, S., Biller, B., Maire, A. -L., Allard, F., Borgniet, S., Lannier, J., Meunier, N., Desort, M., Alecian, E., Chauvin, G., Langlois, M., Henning, T., Mugnier, L., Mouillet, D., Gratton, R., Brandt, T., Mc Elwain, M., Beuzit, L., Tamura, M., Hori, Y., Brandner, W., Buenzli, E., Cheetham, A., Cudel, M., Feldt, M., Kasper, M., Keppler, M., Kopytova, T., Meyer, M., Perrot, C., Rouan, D., Salter, G., Schmidt, T., Sissa, E., Zurlo, A., Wildi, F., Blanchard, P., De Caprio, V., Delboulbé, A., Maurel, D., Moulin, T., Pavlov, A., Rabou, P., Ramos, J., Roelfsema, R., Rousset, G., Stadler, E., Rigal, François, Weber, L., Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology [2007-2019] (Grenoble INP [2007-2019])-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology [2007-2019] (Grenoble INP [2007-2019])-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Bordelais de Recherche en Informatique (LaBRI), Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure d'Électronique, Informatique et Radiocommunications de Bordeaux (ENSEIRB)-Université Sciences et Technologies - Bordeaux 1-Université Bordeaux Segalen - Bordeaux 2, Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Leiden Observatory [Leiden], Universiteit Leiden [Leiden], Laboratoire Gemini (LG), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS), University of Exeter, 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), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Department of Astronomy, Stockholm University, Zentrum für Astronomie der Universität Heidelberg (ZAH), Universität Heidelberg [Heidelberg], INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Physikalisches Institut [Bern], Universität Bern [Bern], Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève (UNIGE), Department of Biochemistry and Molecular Biology, Mayo Clinic, Observatoire de Paris, Université Paris sciences et lettres (PSL), Laboratoire d'Etude des Phénomènes de Transfert Appliqués aux Bâtiments (LEPTAB), Université de La Rochelle (ULR), Centre de Recherche en Nutrition Humaine d'Auvergne (CRNH d'Auvergne), Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), ONERA - The French Aerospace Lab [Châtillon], Université Paris Saclay (COmUE)-ONERA, Riken, RIKEN - Institute of Physical and Chemical Research [Japon] (RIKEN), National Astronomical Observatory of Japan (NAOJ), Recherche Nutrition Humaine, Hôpital de l'Hôtel-Dieu de Clermont-Ferrand, Groupe d'Acoustique de l'Université de Sherbrooke (GAUS), Département de génie mécanique [Sherbrooke], Université de Sherbrooke [Sherbrooke]-Université de Sherbrooke [Sherbrooke], University of Geneva, Genève, Chimie, Ingénierie Moléculaire et Matériaux d'Angers (CIMMA), Université d'Angers (UA)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Capodimonte (OAC), Laboratoire d'Informatique Fondamentale et Appliquée de Tours (LIFAT), Centre National de la Recherche Scientifique (CNRS)-Université de Tours-Institut National des Sciences Appliquées - Centre Val de Loire (INSA CVL), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), NOVA Optical Infrared Instrumentation Group, European Synchrotron Radiation Facility (ESRF), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Grenoble (LAOG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université Paris-Sud - Paris 11 (UP11)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris), PSL Research University (PSL), ONERA, Laboratoire de Chimie, Ingénierie Moléculaire et Matériaux d'Angers (CIMMA), Université de Tours-Institut National des Sciences Appliquées - Centre Val de Loire (INSA CVL), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université d'Angers (UA), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, School of Earth and Space Exploration, Arizona State University, P.O. Box 871404, Tempe, Leiden Observatory, Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA), Physikalisches Institut, Universitat Bern, Gesellschaftsstrasse 6, 3012, Bern, Switzerland, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), INAF-Osservatorio Astronomico di Brera (INAF-OAB), Haute résolution angulaire en astrophysique, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Pôle Planétologie du LESIA, Astrobiology Center of NINS (ABC), National Institutes of Natural Sciences [Tokyo] (NINS), Department of Astronomy, Stockholm University, AlbaNova University Center, 106 91, Stockholm, Sweden, Harvard University, ISDC, Geneva Observatory, University of Geneva, Instituto de Astronomia y Ciencias Planetarias de Atacama, Copayapu 485, Copiap, Atacama, Chile, Laboratoire Franco-Chilien d'Astronomie, UMI 3386, Institute for Advanced Study, Einstein Drive, Princeton, Exoplanets and Stellar Astrophysics Laboratory, NASA Goddard Space Flight Center, European Southern Observatory (ESO), Institute for Astronomy, Department of Physics, ETH Zürich, Nucleo de Astronomia, Facultad de Ingenieria y Ciencias, Universidad Diego Portales, Av. Ejercito 441, Santiago, Chile, TNO/TPD-Space Instrumentation, and Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)
Subjects: 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Population, FOS: Physical sciences, Astrophysics, 01 natural sciences, Luminosity, Angular diameter, 0103 physical sciences, education, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, education.field_of_study, [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Mechanics of the fluids [physics.class-ph], Stellar rotation, Astronomy and Astrophysics, Radius, Surface gravity, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Radial velocity, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Spectral energy distribution, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: The G-type star GJ504A is known to host a 3 to 35 MJup companion whose temperature, mass, and projected separation all contribute to make it a test case for the planet formation theories and for atmospheric models of giant planets and light brown dwarfs. We collected data from the CHARA interferometer, SOPHIE spectrograph, and VLT/SPHERE high contrast imager to revisit the properties of the system. We measure a radius of 1.35+/- 0.04Rsun for GJ504A which yields isochronal ages of 21+/-2Myr or 4.0+/-1.8Gyr for the system and line-of-sight stellar rotation axis inclination of $162.4_{-4.3}^{+3.8}$ degrees or $18.6_{-3.8}^{+4.3}$ degrees. We re-detect the companion in the Y2, Y3, J3, H2, and K1 dual band SPHERE images. The complete 1-4 $\mu$m SED shape of GJ504b is best reproduced by T8-T9.5 objects with intermediate ages ($\leq1.5$Gyr), and/or unusual dusty atmospheres and/or super-solar metallicities. All six atmospheric models used yield $\mathrm{T_{eff}=550 \pm 50}$K for GJ504b and point toward a low surface gravity (3.5-4.0 dex). The accuracy on the metallicity value is limited by model-to-model systematics. It is not degenerate with the C/O ratio. We derive $\mathrm{log\:L/L_{\odot}=-6.15\pm0.15}$ dex for the companion compatible with masses of $\mathrm{M=1.3^{+0.6}_{-0.3}M_{Jup}}$ and $\mathrm{M=23^{+10}_{-9} M_{Jup}}$ for the young and old age ranges, respectively. The semi-major axis (sma) is above 27.8 au and the eccentricity lower than 0.55. The posterior on GJ~504b's orbital inclination suggests a misalignment with GJ~504A rotation axis. We combine the radial velocity and multi-epoch imaging data to exclude additional objects (90\% prob.) more massive than 2.5 and 30 $\mathrm{M_{Jup}}$ with sma in the range 0.01-80 au for the young and old system ages, respectively. The companion is in the envelope of the population of planets synthetized with our core-accretion model., Comment: 33 pages, 25 figures. Accepted in Astronomy and Astrophysics
Published: 2018
Full Text: View/download PDF

46. Airborne high resolution SAR imagery

Author: Oriot, Hélène, André, Cécile, DEMR, ONERA, Université Paris Saclay (COmUE) [Palaiseau], Université Paris Saclay (COmUE)-ONERA, UNIVERSITE DE PARIS-SUD CENTRE D'ORSAY, and Sylvie MARCOS
Subjects: [PHYS]Physics [physics], SYSTEME RADAR, IMAGERIE SAR, INTERFEROMETRIE, [SPI] Engineering Sciences [physics], DETECTION CIBLE MOBILE, SAR PROCESSING, AEROPORTEE, SAR IMAGERY, RADAR, [PHYS] Physics [physics], INTERFEROMETRY, [SPI]Engineering Sciences [physics], RADAR SYSTEM, GMTI, AIRBORNE SENSOR
Abstract: With the growing number of operating spatial systems, SAR imagery has become a major topic of research in the remote sensing community. In France, most of the research focuses on the exploitation of satellite SAR images. On the contrary, given the lower availability of such data, the airborne domain concerns a smaller community. This report aims at presenting the specificities of high-resolution airborne radar imagery and their impacts on multi-channel applications.A first part is devoted to a theoretical analysis of airborne SAR processing in its different modalities. The various SAR processing approaches adapted to high resolution are presented from a geometric point of view rather than frequential point of view. Then, the principles of multichannel processing are presented with emphasis on the phenomenology associated with the improvement of the resolution: link between image registration and interferometric phase, behavior of point like scatterers, anisotropic or surfacic backscatters. A second part is dedicated to the impact of real acquisition systems on SAR processing and multichannel applications. Issues related to the radar hardware, the antenna particularities, non-linearities of the trajectories are discussed and illustrated on applications such as calibration of polarimetric data, 3D extraction, ground moving target detection ., Avec la multiplication des systèmes spatiaux, l’imagerie radar fait l’objet de nombreux travaux de recherche. En France, la majorité des travaux se concentre sur l’exploitation des images radar spatiales, de résolution de plus en plus fine. Le domaine aéroporté concerne une communauté plus restreinte étant donnée la moindre disponibilité de telles données. Ce rapport a pour vocation de présenter les spécificités de l’imagerie radar aéroportée haute résolution et d’en comprendre les impacts sur les applications multi-voies.Une première partie est consacrée à l’analyse théorique du traitement SAR aéroporté dans ses différentes modalités. Les diverses approches de traitement SAR adaptés à la haute résolution sont présentées selon un point de vue géométrique plutôt que fréquentiel. Puis, toujours sous ce même angle, les principes des traitements multivoies sont abordés en insistant sur les phénomènes apparaissant avec l’amélioration de la résolution : lien entre recalage d’images et phase interférométrique, comportement des rétrodiffuseurs ponctuels, surfaciques et anisotropes.Une deuxième partie est consacrée à l’étude de l’impact d’un système réel d’acquisition sur le traitement SAR et les applications multivoies. Les problématiques liées à la chaîne radar, aux diagrammes d’antennes, aux trajectoires non linéaires sont abordées.Enfin, différents travaux d’exploitation d’images radar haute résolution aéroportées (calibration de données polarimétriques, extraction du 3D sur les images SAR, détection de cibles mobiles) illustrent le propos.
Published: 2018

47. VLT/SPHERE astrometric confirmation and orbital analysis of the brown dwarf companion HR 2562 B

Author: Anne-Lise Maire, Hervé Beust, Anne-Marie Lagrange, Daniel Rouan, D. Perret, Stéphane Udry, Miriam Keppler, S. Daemgen, Michael Meyer, M. Feldt, Arthur Vigan, D. Maurel, Thomas Henning, L. Rodet, R. G. Gratton, J. C. Augereau, Hubert Klahr, C. Petit, Johan Olofsson, A. Delboulbe, Philippe Thébault, Silvano Desidera, R. Ligi, Maud Langlois, Wolfgang Brandner, Faustine Cantalloube, Valentina D'Orazi, A. Roux, Mickael Bonnefoy, Jose Ramos, Thibaut Moulin, L. Abe, Janis Hagelberg, L. Weber, Dino Mesa, M. Carle, H. Le Coroller, Anthony Boccaletti, Matthias Samland, A. Zurlo, Raphaël Galicher, A. Pavlov, Philippe Feautrier, Markus Janson, T. Schmidt, Yves Magnard, C. Lazzoni, Gael Chauvin, F. Rigal, Max-Planck-Institut für Astronomie (MPIA), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Dipartimento di Fisica e Astronomia G. Galilei, Università di Padova, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), INCT, Universidad de Atacama, calle Copayapu 485, Copiapo, Atacama, Chile, Laboratoire Franco-Chilien d'Astronomie, UMI 3386, Department of Astronomy, Stockholm University, AlbaNova University Center, 106 91, Stockholm, Sweden, Departamento de Física y Astronomía, Universidad de Valparaiso, Institute for Astronomy, Department of Physics, ETH Zürich, Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), University of Michigan, INAF - Osservatorio Astronomico di Brera (OAB), ISDC, Geneva Observatory, University of Geneva, Nucleo de Astronomia, Facultad de Ingenieria, Universidad Diego Portales, Avenida Ejercito 441, Santiago, Chile, Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA), ONERA - The French Aerospace Lab [Palaiseau], ONERA-Université Paris Saclay (COmUE), Astronomical Institute Anton Pannekoek, University of Amsterdam, Max-Planck-Gesellschaft, Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Università degli Studi di Padova = University of Padua (Unipd), Instituto de Astronomia y ciencias Planetarias de Atacama (INCT), Universidad de Atacama, Laboratoire Franco-Chilien d'Astronomie (LFCA), Universidad de Chile = University of Chile [Santiago] (UCHILE)-Pontificia Universidad Católica de Chile (UC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Universidad de Concepción - University of Concepcion [Chile], Stockholm University, Universidad de Valparaiso [Chile], Institute of Astronomy [ETH Zürich], Department of Physics [ETH Zürich] (D-PHYS), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich)- Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), University of Michigan [Ann Arbor], University of Michigan System, Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève = University of Geneva (UNIGE), Universidad Diego Portales [Santiago] (UDP), Universidad de Chile = University of Chile [Santiago] (UCHILE), Observatoire de la Côte d'Azur (OCA), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), DOTA, ONERA, Université Paris Saclay (COmUE) [Palaiseau], Astronomical Institute Anton Pannekoek (AI PANNEKOEK), University of Amsterdam [Amsterdam] (UvA), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Universita degli Studi di Padova, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Universidad de Concepción [Chile]-Pontificia Universidad Católica de Chile (UC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Universidad de Chile, Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich)-Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Université de Genève (UNIGE), Universidad de Chile, Centre National de la Recherche Scientifique (CNRS), DOTA, ONERA, Université Paris Saclay [Palaiseau], ONERA-Université Paris-Saclay, Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), and Université Paris Saclay (COmUE)-ONERA
Subjects: 010504 meteorology & atmospheric sciences, BROWN DWARFS, Brown dwarf, FOS: Physical sciences, METHODS: DATA ANALYSIS, Astrophysics, 01 natural sciences, [SPI]Engineering Sciences [physics], 0103 physical sciences, TECHNIQUES: IMAGE PROCESSING, Coordination network, Astrophysics::Solar and Stellar Astrophysics, European commission, STARS: INDIVIDUAL: HR 2562, 010303 astronomy & astrophysics, Orbital analysis, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, [PHYS]Physics [physics], Astronomy and Astrophysics, PLANETS AND SATELLITES: DYNAMICAL EVOLUTION AND STABILITY, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, TECHNIQUES: HIGH ANGULAR RESOLUTION, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: Context. A low-mass brown dwarf has been recently imaged around HR 2562 (HD 50571), a star hosting a debris disk resolved in the far infrared. Interestingly, the companion location is compatible with an orbit coplanar with the disk and interior to the debris belt. This feature makes the system a valuable laboratory to analyze the formation of substellar companions in a circumstellar disk and potential disk-companion dynamical interactions. Aims. We aim to further characterize the orbital motion of HR 2562 B and its interactions with the host star debris disk. Methods. We performed a monitoring of the system over ~10 months in 2016 and 2017 with the VLT/SPHERE exoplanet imager. Results. We confirm that the companion is comoving with the star and detect for the first time an orbital motion at high significance, with a current orbital motion projected in the plane of the sky of 25 mas (~0.85 au) per year. No orbital curvature is seen in the measurements. An orbital fit of the SPHERE and literature astrometry of the companion without priors on the orbital plane clearly indicates that its orbit is (quasi-)coplanar with the disk. To further constrain the other orbital parameters, we used empirical laws for a companion chaotic zone validated by N-body simulations to test the orbital solutions that are compatible with the estimated disk cavity size. Non-zero eccentricities (>0.15) are allowed for orbital periods shorter than 100 yr, while only moderate eccentricities up to ~0.3 for orbital periods longer than 200 yr are compatible with the disk observations. A comparison of synthetic Herschel images to the real data does not allow us to constrain the upper eccentricity of the companion., Accepted for publication in A&A. 14 pages, 14 figures, 3 tables. Updated to match published paper. Bug in the computation of the distributions of times at periastron passages corrected, minor effects on other orbital parameters
Published: 2018
Full Text: View/download PDF

48. The Dubins Car Problem with Delay and Applications to Aeronautics Motion Planning Problems

Author: Bonalli, Riccardo, Hérissé, Bruno, Maurer, Helmut, Trélat, Emmanuel, Laboratoire Jacques-Louis Lions (LJLL (UMR_7598)), Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Control And GEometry (CaGE ), Laboratoire Jacques-Louis Lions (LJLL), Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Inria de Paris, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), DTIS, ONERA, Université Paris Saclay (COmUE) [Palaiseau], Université Paris Saclay (COmUE)-ONERA, University of Münster, and ONERA-Université Paris Saclay (COmUE)
Subjects: [MATH.MATH-OC]Mathematics [math]/Optimization and Control [math.OC], ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2017

49. Online estimation of the wavefront outer scale profile from adaptive optics telemetry

Author: James Osborn, Timothy Butterley, A. Guesalaga, Benoit Neichel, Thierry Fusco, Elena Masciadri, J.-F. Sauvage, Carlos Correia, ITA, Pontificia Universidad Católica de Chile (UC), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Department of Physics, Centre for Advanced Instrumentation, Durham University, INAF - Osservatorio Astrofisico di Arcetri (OAA), Istituto Nazionale di Astrofisica (INAF), DOTA, ONERA, Université Paris Saclay (COmUE) [Palaiseau], ONERA-Université Paris Saclay (COmUE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), and Université Paris Saclay (COmUE)-ONERA
Subjects: Wavefront, Physics, Coherence time, Scale (ratio), business.industry, Turbulence, [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Astronomy and Astrophysics, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 01 natural sciences, Deformable mirror, law.invention, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], 010309 optics, Telescope, Optics, Space and Planetary Science, law, 0103 physical sciences, Adaptive optics, Linear combination, business, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS
Abstract: We describe an online method to estimate the wavefront outer scale profile, L0(h), for very large and future extremely large telescopes. The stratified information on this parameter impacts the estimation of the main turbulence parameters [turbulence strength, Cn2(h); Fried's parameter, r0; isoplanatic angle, θ0; and coherence time, τ0) and determines the performance of wide-field adaptive optics (AO) systems. This technique estimates L0(h) using data from the AO loop available at the facility instruments by constructing the cross-correlation functions of the slopes between two or more wavefront sensors, which are later fitted to a linear combination of the simulated theoretical layers having different altitudes and outer scale values. We analyse some limitations found in the estimation process: (I) its insensitivity to large values of L0(h) as the telescope becomes blind to outer scales larger than its diameter; (II) the maximum number of observable layers given the limited number of independent inputs that the cross-correlation functions provide and (III) the minimum length of data required for a satisfactory convergence of the turbulence parameters without breaking the assumption of statistical stationarity of the turbulence. The method is applied to the Gemini South multiconjugate AO system that comprises five wavefront sensors and two deformable mirrors. Statistics of L0(h) at Cerro Pachón from data acquired during 3 yr of campaigns show interesting resemblance to other independent results in the literature. A final analysis suggests that the impact of error sources will be substantially reduced in instruments of the next generation of giant telescopes.
Published: 2017
Full Text: View/download PDF

50. First Scattered-light Images of the Gas-rich Debris Disk around 49 Ceti

Author: C. H. Chen, A. Boccaletti, Abhijith Rajan, C. del Burgo, Dimitri Mawet, J. C. Augereau, Anne-Marie Lagrange, Christophe Pinte, Julien Milli, Steve Ertel, Elena Gofas-Salas, S. Wolff, J. B. Hagan, Aki Roberge, Dean C. Hines, Mamadou N'Diaye, Rémi Soummer, M. D. Perrin, Z. Wahhaj, David A. Golimowski, Olivier Absil, W. R. F. Dent, Elodie Choquet, Julien Girard, P. Hibon, Glenn Schneider, Mark Booth, David Mouillet, Mark C. Wyatt, Luca Matrà, Laurent Pueyo, Grant M. Kennedy, John H. Debes, C. A. Gomez Gonzalez, Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, European Southern Observatory [Santiago] (ESO), European Southern Observatory (ESO), Space Telescope Science Institute (STSci), Exoplanets and Stellar Astrophysics Lab, NASA Goddard Space Flight Center (GSFC), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Astrophysikalisches Institut und Universitätssternwarte, Pontificia Universidad Católica de Chile (UC), Space Sciences, Technologies and Astrophysics Research Institute (STAR), Université de Liège, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Instituto Nacional de Astrofísica, Óptica y Electrónica (INAOE), Atacama Large Millimeter/submillimeter Array (ALMA), Steward Observatory, University of Arizona, DOTA, ONERA, Université Paris Saclay [Palaiseau], ONERA-Université Paris-Saclay, Institute of Astronomy [Cambridge], University of Cambridge [UK] (CAM), Caltech Department of Astronomy [Pasadena], California Institute of Technology (CALTECH), Université Côte d'Azur (UCA), Arizona State University [Tempe] (ASU), Johns Hopkins University (JHU), NASA-California Institute of Technology (CALTECH), GSFC Exoplanets and Stellar Astrophysics Laboratory, Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), DOTA, ONERA, Université Paris Saclay (COmUE) [Palaiseau], ONERA-Université Paris Saclay (COmUE), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA), Université Paris Saclay (COmUE)-ONERA, Kennedy, Grant [0000-0001-6831-7547], Matr<U+FFFD>, Luca [0000-0003-4705-3188], Wyatt, Mark [0000-0001-9064-5598], and Apollo - University of Cambridge Repository
Subjects: 010504 meteorology & atmospheric sciences, FOS: Physical sciences, CIRCUMSTELLAR MATTER, Astrophysics, 01 natural sciences, 0103 physical sciences, TECHNIQUES: IMAGE PROCESSING, Angular resolution, Absorption (electromagnetic radiation), 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, [PHYS]Physics [physics], Debris disk, Infrared excess, Very Large Telescope, Scattering, Astronomy and Astrophysics, stars: individual (49 Ceti), Debris, [PHYS.PHYS.PHYS-SPACE-PH]Physics [physics]/Physics [physics]/Space Physics [physics.space-ph], 13. Climate action, Space and Planetary Science, [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], STAR : INDIVUDAL (49 CETI), Main sequence, Astrophysics - Earth and Planetary Astrophysics
Abstract: We present the first scattered-light images of the debris disk around 49 ceti, a ~40 Myr A1 main sequence star at 59 pc, famous for hosting two massive dust belts as well as large quantities of atomic and molecular gas. The outer disk is revealed in reprocessed archival Hubble Space Telescope NICMOS F110W images, as well as new coronagraphic H band images from the Very Large Telescope SPHERE instrument. The disk extends from 1.1" (65 AU) to 4.6" (250 AU), and is seen at an inclination of 73degr, which refines previous measurements at lower angular resolution. We also report no companion detection larger than 3 M_Jup at projected separations beyond 20 AU from the star (0.34"). Comparison between the F110W and H-band images is consistent with a grey color of 49 ceti's dust, indicating grains larger than >2microns. Our photometric measurements indicate a scattering efficiency / infrared excess ratio of 0.2-0.4, relatively low compared to other characterized debris disks. We find that 49 ceti presents morphological and scattering properties very similar to the gas-rich HD 131835 system. From our constraint on the disk inclination we find that the atomic gas previously detected in absorption must extend to the inner disk, and that the latter must be depleted of CO gas. Building on previous studies, we propose a schematic view of the system describing the dust and gas structure around 49 ceti and hypothetic scenarios for the gas nature and origin., Accepted for publication in ApJL. 7 pages, 4 figures
Published: 2017
Full Text: View/download PDF

Catalog

Books, media, physical & digital resources

See catalog results

Searchworks

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

Search

Search Constraints

Refine your results

Search Limiters

Topic

Publication Year Range

Language

Journal

Database

Publisher

72 results on '"Université Paris Saclay (COmUE)-ONERA"'

Search Results

Catalog

Select search scope, currently: Articles

Catalog

books, media & more in Jio Institute collections

Articles

journal articles & other e-resources