Enhancing physical activity assessment in a French large cohort: Feasibility and acceptability of using wearable accelerometers

International audienc

Révolutions technologiques, révolution du travail ?

International audienc

Towards the digital twin of a multi-stage forming process for metallic sheets

International audienceDigital twins are a major constituent of advanced and smart manufacturing, to decrease the time tomarket, improve process efficiency and reduce waste production. There seems to be a common unders-tanding on the different levels of integration of the communication between the physical object and thedigital object, i.e., digital model, shadow and twin, with the digital twin being the stage when it sendsactions to perform in real-time to the physical object, for an efficient execution of the process. In thefield of material forming, digital models are well established nowadays, based on finite element simula-tions and physics-based constitutive equations to represent the material mechanical behavior, althoughin general the high calculation time prevents any real-time interaction. The aim of this study is to designfirst a digital shadow of a progressive multi-step sheet forming process, aiming at a digital twin in asecond step. The target is to adjust the process parameters according to the mechanical properties va-riations. The physical process involves cutting of rectangular blanks, U-draw bending, springback anda last calibration stage to compensate for the springback. To provide a reliable representation of themechanical behavior under complex stress states and large strains, distortional hardening is consideredalong with isotropic hardening. An analysis of variations of the mechanical properties of DP600 steelwas performed, to generate several material parameter sets. Based on finite element simulations of themulti-step process, a sensitivity analysis of the forming process outputs to the mechanical propertiesvariations is carried out. The results highlight the operating principle of the digital twin, stressing outthe required sensors

Towards an embedded architecture based back-end processing for AGV SLAM applications

International audiencePlace recognition plays a crucial role in the Simultaneous Localization and Mapping (SLAM) process of self-driving cars. Over time, motion estimation is prone to accumulating errors, leading to drift. The ability to accurately recognize previously visited areas through the place recognition system allows for the correction of these drift errors in real-time. Recognizing places based on the structural aspects of the environment tends to be more resilient against variations in lighting, which can cause incorrect identifications when using feature-based descriptors. Nevertheless, research has predominantly focused on using depth sensors for this purpose. Inspired by a LiDAR-based approach, we introduce an inter-modal geometric descriptor that leverages the structural information obtained through a stereo camera.Using this descriptor, we can achieve real-time place recognition by focusing on the structural appearance of the scene derived from a 3D vision system. Our experiments on the KITTI dataset and our self-collected dataset show that the proposed approach is comparable to state-of-the-art methods, all while being low-cost. We studied the algorithm’s complexity to propose an optimized parallelization on GPU and FPGA architectures. Performance evaluation on different hardware (Jetson AGX Xavier and Arria 10 SoC) shows that the real-time requirements of an embedded system are met. Compared to a CPU implementation, processing times showed a speed-up between 4x and 10x, depending on the architecture

Méthode d’évaluation en temps réel du style de prise de décision de l’utilisateur pour les scénarios d’un simulateur d’évacuation

International audienceThe aim of this research work is, firstly, to develop an algorithm for observing and classifying in real time the user's decision-making style in a situation of uncertainty in a virtual environment. Secondly, this algorithm will enable us to adapt the scenario in real time, so that the user in simulation is faced with personalized situations of increasing difficulty. We will establish a multi-factorial model of decision-making under uncertainty. Experiments, statistical methods and this model will enable us to determine the extent to which each of these factors influences decision-making in a complex situation. We will then be able to determine how an algorithm can typologize in real-time decision-making categories in a way that is useful for a scenario generator. The model will be applied to a priority use case: the simulation of building evacuation in the event of fire.L’objet de ce travail de recherche est, dans un premier temps, de développer un algorithme d’observation et de classification en temps réel du style de prise de décision de l’utilisateur·ice en situation d'incertitude dans un environnement virtuel. Dans un second temps, celui-ci permettra d’adapter le scénario en temps réel pour mettre la personne en simulation face à des situations personnalisées adaptées de difficulté croissante. Nous établirons un modèle multi-factoriel de prise de décision en situation d'incertitude. Des expériences, méthodes statistiques et ce modèle nous permettront de savoir dans quelle mesure chacun de ses facteurs influence la prise de décision dans une situation complexe. Nous pourrons ensuite déterminer comment un algorithme peut typologiser les catégories de prise de décision en temps réel de manière utile pour un générateur de scénario. Le modèle sera appliqué dans un cas d’usage prioritaire : la simulation d’évacuation de bâtiment en cas d’incendie

Madagascar : le rôle clé des réseaux sociaux dans la chute du pouvoir

The conversationLa crise politique malgache de 2025 illustre la centralité des dynamiques informationnelles dans les mobilisations contemporaines. Déclenchée par des délestages électriques à Antananarivo, la contestation s’est rapidement muée en mouvement national, structuré et amplifié par les réseaux sociaux. Ces plateformes ont permis la diffusion virale de récits contestataires, la coordination en temps réel des actions et la construction d’une narration politique alternative. La génération Z, acteur numérique majeur, a mobilisé hashtags, vidéos citoyennes et livestreams pour imposer son rythme à l’espace public. L’entrée du CAPSAT sur la scène numérique a marqué une hybridation inédite entre action militaire et communication, accélérant la déstabilisation du pouvoir. Cette séquence révèle une vulnérabilité informationnelle structurelle : absence de veille stratégique, exposition aux campagnes d’amplification étrangères et recomposition rapide des rapports entre État, société et acteurs hybrides

A comparative analysis of active learning and commercial optimization framework: Optimization of submerged entry nozzle in continuous casting

International audienceA comparative analysis of active learning and commercial optimization framework: Optimization of submerged entry nozzle in continuous castin

Is There Such a Thing as Science-Based Consulting? The Intervention-Research Model in Management

International audienceThe article focuses on an intervention-research model in management consulting (MC) allowing to carry out science base consulting processes. It aims to clarify the principles of intervention research and its specific contributions for the creation of knowledge in MC. Based on a reflective analysis of some 2,000 intervention-research studies in management carried out by a French research unit that has specialized in this methodology since 1974, we propose a model of intervention research to carry out science based MC processes. We then apply this model to two contrasting case studies to put it to the test and identify elements that are fruitful for discussion on scientific consultancy and its divergences with consulting without any scientific intend

Dietary consumption trajectory profiles over time of French adults from the NutriNet-Santé cohort (2014-2022): Multicriteria analysis of sustainability

International audienceDietary patterns significantly impact climate change and morbidity, making transitions to sustainable diets urgent. Few studies explore repeated dietary measures collected over several years or variations across distinct consumer profiles characterized by sociodemographic and dietary patterns.Objective: Our study aims to identify dietary trajectory profiles in French adults (2014-2022), assessing environmental, nutritional, and health outcomes.Methods: Consumption data from 17,187 NutriNet-Santé cohort participants (52% women, average age 48y, SD = 16) were collected via food frequency questionnaires in 2014 (weighted to the French Census), 2018, and 2022. Dietary trajectory profiles were modeled using Group-based multi-trajectory modeling based on principal component analysis of energy-adjusted consumption data. Associations with environmental (greenhouse gas (GHG) emissions) and nutritional (adherence to French dietary guidelines, diet quality index) dimensions were assessed via multivariable mixed models. Health impacts were evaluated as Disability-Adjusted Life Years (DALYs)avoided, using the Comparative Risk Assessment approach.Results: Six dietary trajectory profiles (P) with distinct starting diets and evolutions were identified. P0 had average intakes, while P1 and P5 were meat-focused, with P5 showing the highest animal consumption. P3 and P4 leaned plant-based, with P4 maintaining high fish and plant intakes, and P3 increasing ruminant meat. P2 initially high in salty or sweet fatty foods, shifted significantly toward plant-based diets. Over time, GHG emissions decreased (-5% to -14%), diet quality (PNNS-GS2 score) improved (+12% to +174%), and health risks declined in four profiles due to reduced red meat and higher whole grains/fruits but increased for P4 and P5 due to processed meat.Conclusion: These profiles reflect diverse population segments with distinct dietary profiles and degrees of sustainability improvements. However, significant advancements remain limited, highlighting the need for further research on economic, psychological, and cultural factors to guide sustainable changes.</p

Intégration d’un Jumeau Numérique et définition collaborative de ses usages dans le cadre d’une pédagogie active

International audienceEn appui sur le projet JENII, cette contribution se propose de documenter un cas d’usage lié à l’intégration du Jumeau Numérique d’un atelier de production industrielle à un bloc d’enseignement déjà établi depuis plusieurs années en classe préparatoire de formation d’ingénieur. L’étude de la logique de conception et des différents rôles remplis par les acteurs de l’équipe pédagogique donne à voir des dynamiques de prescription (enseignant-concepteur) et de façonnage (tuteurs) des usages dont la mise en dialogue semble alimenter et définir chemin faisant les fonctions remplies par l’ingénieur pédagogique