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Tunable polarization-entangled near-infrared photons from orthogonal GaAs nanowires
No full textQuantum entanglement is a fundamental resource for emerging quantum technologies, enabling secure communication and enhanced sensing. For decades, generating polarization entangled states has been mainly achieved using bulk crystals with spontaneous parametric down conversion (SPDC), preventing scalability and on chip integration. Miniaturizing the quantum source provides access to more versatility and tunability while enabling an easier integration to other devices, notably necessary for satellite-based quantum communication, and eventually reducing fabrication costs. This challenging task can be achieved with Zinc Blende GaAs nanowires. They already have shown an efficient photon pairs generation via SPDC at 1550 nm. Here we demonstrate that a pair of orthogonal GaAs nanowires constitutes a new nanoscale platform to control the quantum state at telecommunication wavelength, enabling a transition from polarization entangled to separable states as a function of the pump polarization, with fidelities reaching 90
Explorer les relations sensibles à la biodiversité :quelle est l’influence des chants d’oiseaux sur le rapportdes citoyens à l’espace urbain ? Une étude des perceptions sonores des espaces végétalisés des habitatscollectifs au sein de la métropole de Lyon
No full textInternational audienceUrban planning faces new challenges that question the place of biodiversity in urban spaces and the benefits it brings to city dwellers. In developing strategies to protect biodiversity, we need to take in consideration the role of residents, particularly those living in private multi-family residential dwellings. These residents can choose to favorize a diversity of species by adapting the layout and management of their gardens. To mobilize them effectively, we need to better understand their relationship with biodiversity and identify ways to encourage them to play a more active role in its protection. One way of creating links with biodiversity is through sound: biodiversity produces sounds that can be appreciated by the public, particularly birds, whose diverse songs depend on the composition and layout of gardens. This article examines the relevance of a sensitive approach based on the sounds produced by biodiversity to better understand the relationship between residents and the city. It explores the emotions and feelings that bird songs provide to residents, the knowledge and values they associate with theses, and assesses whether this auditory component of biodiversity can inspire intentions to transform the city and foster bird protection. To this end, we conducted an in situ survey combining listening sessions and directive interviews with 34 residents living in multi-family residential dwellings in the Metropolis of Lyon. The results show that bird song has a positive impact on the living environment and encourages residents to think about the ecological quality of their garden landscapes. However, résidents do not necessarily perceive theses as connected to other urban areas, and while some express a desire to protect birds, this intention is mostly confined to private spaces.L’aménagement de la ville doit répondre à de nouveaux enjeux qui questionnent la place de la biodiversité dans les espaces urbains et les bénéfices qu’elle apporte aux citadins. Dans les stratégies qui sont déployées pour la valoriser, il ne faut pas négliger le rôle que jouent les habitants vivant notamment dans les copropriétés privées. Ces derniers peuvent en effet choisir de favoriser ou non la présence d’une diversité d’espèces en adaptant l’aménagement et la gestion de leur jardin. Leur mobilisation suppose de mieux comprendre les relations qu’ils entretiennent avec la biodiversité et d’identifier des moyens pour les rendre plus acteurs de sa protection. La relation sonore est une des modalités permettant d’entrer en interaction avec elle : en effet, les espèces animales produisent des sons, audibles par les citoyens. C’est particulièrement vrai pour les oiseaux dont la diversité des chants dépend notamment de la composition et de l’agencement des jardins. Cet article interroge la pertinence d’une approche sensible orientée sur les sons que produit la biodiversité pour mieux appréhender la relation des habitants à la ville. Elle vise à questionner les émotions et les sentiments que procurent les chants d’oiseaux aux habitants, les savoirs et les valeurs qu’ils y associent et à évaluer si cette composante sonore de la biodiversité peut créer une intention de transformer la ville et d’agir en faveur des oiseaux. Pour cela, nous nous sommes appuyés sur une méthode d’enquête in situ, mêlant écoutes et entretiens menés auprès de 34 habitants résidant dans des copropriétés de la Métropole de Lyon. Il en ressort que les chants d’oiseaux influencent favorablement le cadre de vie des habitants. Ils permettent aussi à ces derniers d’engager une réflexion sur la qualité écologique des structures paysagères de leur jardin. Il apparaît en revanche que les habitants ne le pensent pas forcément en continuité avec d’autres espaces de la ville. Si pour certains émerge une volonté de protéger les oiseaux, celle-ci se cantonne plutôt à l’échelle de l’espace privé
Comment les choix de design d'interface mène à des effets environnementaux indirects par l'intensification des usages: Une évaluation environnementale empirique des applications de messagerie
No full textInternational audienceIn sustainable HCI, the 'Cornucopian Paradigm' describes how the expansion of digital services goes hand in hand with the growth of digital infrastructure and its environmental footprint. Yet, the mechanisms driving this paradigm are not well understood at the design level. As a case study, we investigate how messaging apps factor in the cornucopian paradigm by conducting a feature analysis of 17 apps complemented with 12 user interviews. We identify four scale-up mechanisms that explain how design contributes to the cornucopian paradigm. These mechanisms all contribute to use intensification, i.e., digital practices becoming more intensive and leading to more data intensity, to infrastructure expansion, and indirectly to device obsolescence and replacement. Our analysis of use intensification builds upon a set of recurring cornucopian design patterns we identified in messaging apps. To mitigate the cornucopian paradigm, we propose a set of moderation heuristics to guide design decisions.Dans le champ de l'IHM soutenable (SHCI), le « paradigme de la corne d'abondance » décrit comment l'expansion des services numériques s'accompagne de l'expansion des infrastructures numériques et de leur impact environnemental. Pourtant, les mécanismes sous-jacents à ce paradigme restent mal compris au niveau du design. À titre d'étude de cas, nous analysons comment les applications de messagerie s'intègrent à ce paradigme en réalisant une analyse des fonctionnalités de 17 applications, complétée par 12 entretiens utilisateurs. Nous identifions quatre mécanismes d'accroissement qui expliquent comment le design contribue au paradigme de la corne d'abondance. Ces mécanismes contribuent tous à l'intensification des usages (quand les pratiques numériques deviennent plus intensives, entraînant une augmentation du volume de données), à l'expansion des infrastructures et, indirectement, à l'obsolescence et au remplacement des appareils. Notre analyse de l'intensification des usages s'appuie sur un ensemble de design patterns récurrents liés au paradigme de la corne d'abondance, que nous avons identifiés dans les applications de messagerie. Afin d'atténuer les effets de ce paradigme, nous proposons un ensemble d'heuristiques de modération pour guider les décisions de design numérique
DEFORMATION-AWARE SIMULATOR FOR HANDHELD ULTRASOUND IMAGING
No full textInternational audienceRealistic ultrasound simulation is essential for training and algorithm development. However, most existing methods generate single-frame images from thin slices of the probe's field of view, neglecting tissue deformation and spatial continuity across frames. We propose a physics-based simulation pipeline, fully compatible with any scatterer-based ultrasound simulator, which employs finite element modeling to update local scatterer maps under large-scale stability constraints, given the probe trajectory and tissue geometry. The framework produces continuous and anatomically accurate ultrasound sequences with physically consistent speckle evolution, providing a practical tool for training, visualization, and the development of freehand ultrasound reconstruction algorithms.</div
Review of Prognosis Approaches Applied to Power SiC MOSFETs for Health State and Remaining Useful Life Prediction
No full textInternational audienceThe use of Silicon Carbide (SiC) MOSFETs significantly improves converter performance by increasing efficiency and reducing costs, to the detriment of electro-magnetic emission and reliability. Implementing a predictive maintenance strategy based on a prognosis tool can mitigate this limitation. This literature review offers a methodological synthesis of prognosis design tools for SiC MOSFETs, while also encompassing studies on IGBTs and silicon-based power MOSFETs where these approaches are transferable. The analysis focuses on wear-out prognosis under nominal operating conditions of standard package device, excluding environmental constraints. Articles published up to 2025 were identified in the OpenAlex database using a keyword-based search and manually filtered according to the study scope. Most reviewed works rely on Data-Based prognosis methods, mostly based on neural networks, though out-of-sample validation remains uncommon. Our study also highlights the dependence of Data-Based prognosis performance on the shape of degradation indicator trends. Moreover, the estimation of prediction uncertainty is rarely addressed in the reviewed literature. Despite notable methodological advances, ensuring the reliability of prognosis tools for SiC MOSFETs remains an ongoing research challenge
Numerical analysis of 3D crack initiation under rolling contact fatigue in polycrystals with subsurface inclusions and surface dents
No full textInternational audienceRolling contact fatigue (RCF) remains a critical challenge in the design and longevity of mechanical components such as rolling element bearings, gears, and railway tracks. This study presents a novel numerical model to simulate crack initiation under RCF conditions, focusing on both subsurface and surface initiation mechanisms. The model incorporates polycrystalline microstructures generated with Voronoi tessellations, and random crystallographic orientations. Contact stresses are computed using the highly efficient Green-FFT method, enabling high resolution 3D analysis. The Tanaka–Mura fatigue crack initiation model is used. This model is grounded in the physical mechanism of dislocation energy accumulation within slip bands, with initiation occurring when the accumulated energy reaches a critical fracture energy. Slip band geometry is determined based on grain orientation and geometry. The model is applied to two scenarios: subsurface initiation near an inclusion and surface initiation near a dent. By simulating multiple microstructures, statistical analyses of crack position, orientation, and initiation life are conducted. Key results include the influence of inclusion stiffness on initiation sites, the alignment of cracks near inclusions, and the preferential initiation of cracks near dents. Additionally, increasing Hertz pressure reduces mean initiation life and decreases its variability, while the number of grains within the stress concentration volume significantly affect initiation life dispersion. The study highlights the necessity of 3D modeling to capture the complex, out-of-plane crack initiation behaviors that cannot be adequately represented in 2D simulations
Actes de la 9ème édition du colloque Pédagogie et Formation du Groupe INSA: Adaptation des parcours de formation aux nouveaux enjeux des métiers de l'ingénieur : quelles transformations et quels impacts ?
No full textNational audienceL’évolution du métier d’ingénieur implique une nécessaire réévaluation des parcours de formation, deleurs contenus, des méthodes et outils d’enseignement-apprentissage. À partir de retours d’expérienceet d’expérimentations dans nos établissements, nous pourrons analyser l’impact de ces transformationssur les acquis des étudiants, le développement de leurs compétences et réfléchir aux moyens de favoriserleur engagement dans ces différents dispositifs.La 9e édition du colloque Pédagogie et Formation du Groupe INSA entend questionner ces problématiqueset permettre d’échanger sur les actions en place, le déploiement de projets à l’échelle du groupe (notamment INSA 2025) et les partenariats développés ces deux dernières années
Hotspots Analysis and Prediction for Mobile Networking Applications
No full textInternational audienceUnderstanding the dynamics of mobile traffic is highly valuable for a variety of fields, such as transportation and networking. In particular, analyzing hotspots, i.e., areas presenting an increased popularity at certain times, is crucial for adequate planning and management operations. Yet, despite its importance, we lack today a precise definition of the term hotspot in the community. The essential of this contribution is based on a unique mobile phone dataset collected by a French mobile operator in the city of Paris. In this work, we propose a new definition for the hotspot concept while highlighting the major weaknesses of the literature. Moreover, we provide an extensive benchmarking for the hotspot forecasting problem. Our results show that Long Short-Term Memory (LSTM) gives the best performance for the hotspot prediction problem, and we consider it for a robotic aerial base station (RABS) deployment application. In order to minimize the RABSs travel distance, we mathematically model the problem and introduce a greedy and Particle Swarm Optimization (PSO) algorithms to solve it. The results in terms of coverage ratio and travel distance showcase the difference between a prediction-based approach and a non-prediction-based approach
Quand le cinéma révèle les héritages industriels de la ville
No full textInternational audienceLe Juge Fayard, dit "le Shériff” (The Judge Fayard, "aka the Sheriff") is a film directed by Yves Boisset in 1977 and shot almost entirely in Saint-Étienne in 1976. This conference took place at the Saint-Étienne's Cinematheque, following the screening of the film, for an audience of researchers, students and the general public. It offers a look back at the various filming locations, with a particular focus on industrial heritage: Saint-Étienne as seen by the Juge Fayard."Le Juge Fayard, dit le Shériff" est un film réalisé par Yves Boisset en 1977 et presque intégralement tourné à Saint-Étienne en 1976. Cette conférence se tient à la Cinémathèque de Saint-Étienne, à la suite de la projection du film, devant un auditoire regroupant chercheurs, étudiants et grand public. Elle propose de retour sur les différents lieux de tournage, en s'arrêtant plus particulièrement sur les héritages industriels : Saint-Étienne vue par le Juge Fayard
EFFECT OF NON-UNIFORM CASING TREATMENT ON THE PERFORMANCE AND OPERABILITY OF THE ECL5 FAN STAGE
No full textThis study investigates unsteady aeroelastic phenomena occurring at off-design conditions in the open test case ECL5 fan stage, a configuration representative of modern lightweight ultrahigh bypass ratio (UHBR) architectures. Both simulations and experiments reveal the onset of small-scale aerodynamic disturbances along subsonic speed lines, known to trigger convective Non-Synchronous Vibration (NSV). This NSV, observed experimentally across 55-90% design speed and involving multiple blade eigenmodes, poses significant risks to fan operability and structural integrity. A promising mitigation strategy is the use of axial-slot casing treatments, which reduce blockage by extracting low-momentum flow in the rotor tip region and reinjecting it upstream with a more favourable momentum. This mechanism disrupts the development of coherent aerodynamic disturbance patterns, thereby delaying or suppressing NSV inception.The present work focuses on designing and evaluating nonuniform casing treatments for the ECL5 fan stage, with emphasis on maintaining performance outside NSV-critical regions. Unlike previous studies that primarily optimize fully circumferential configurations, this investigation explores the potential of partial treatments. Such circumferentially non-uniform designs reduce performance penalties while still preventing disturbances growth.A comprehensive numerical campaign was conducted, including four treatment configurations assessed over multiple speeds and mass flow rates. Results demonstrate that partial treatments can reproduce much of the stabilizing effect of fullcoverage treatments while limiting efficiency losses. The findings deliver design criteria for maximizing NSV suppression with minimal performance impact.</div