HAL-Université de Bretagne Occidentale
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Environnement et climat : brève sociohistoire pour les ingénieurs
No full textInternational audienceThis article provides a historical perspective on environmental issues to help a better understandig of the current climate situation. From the 1970s to 2020, a panorama emerges from the fields of ecological science, political philosophy, environmental management and climate governance, highlighting the tensions surrounding these issues. It appears that the warnings of the 1970s and 1980s were not taken seriously enough: economists, industrialists and political leaders downplayed the damage caused by Western lifestyles. In particular, they discredited critics and maintained the status quo of growth.Cet article propose une mise en perspective historique des questions environnementales pour aider à mieux appréhender la situation climatique actuelle. Ainsi se dessine, des années 1970 à 2020, entre science de l’écologie, philosophie politique, gestion de l’environnement et gouvernance du climat, un panorama qui met en évidence les tensions autour de ces questions. Il apparaît que les alertes des années 1970 et 1980 n’ont pas été suffisamment prises au sérieux : économistes, industriels et dirigeants politiques ont minimisé les nuisances engendrées par le mode de fonctionnement occidental. Ils en ont notamment discrédité les critiques, et ont maintenu le statu quo de la croissance
Magnetic pulse welding of Al-5754 with Al-7075 and MARS 380: Weldability windows and ballistic testing
No full textInternational audienceJoining dissimilar materials encounters significant engineering challenges due to the contrast in material properties that makes conventional welding not feasible. Magnetic Pulse Welding (MPW) offers a solid-state joining technique that overcomes these issues by using impact to create strong bonds without melting the substrate materials. This study investigates the weldability of aluminum alloy Al-5754 with Al-7075 and MARS 380 steel, used in armouring solutions of defense systems, by the use of MPW. In this work, weldability windows are investigated by varying standoff distances between the coating material and its substrate (0.25-4.5 mm) and discharge energies (5-13 kJ) with both O-shape and U-shape inductors. Mechanical strength of the welded joints were assessed through single lap shear tests, identifying optimal welding parameters. Then, the velocity profiles of the flyer plates were measured using heterodyne velocimetry to understand the dynamics of the impact. Then, substructures assembled with the optimal welding conditions were subjected to ballistic testing using 7.62×51 mm NATO and 9×19 mm Parabellum munitions to evaluate the resilience of the welds under ballistic impact. The outcomes demonstrate that MPW effectively joins Al-5754 with both Al-7075 and MARS 380, producing robust welds capable of withstanding ballistic impacts under certain conditions. This research advances the application of MPW in lightweight ballistic protection of defense systems, contributing to the development of more resilient and lighter protective structures
Hands Off, Avatars On : vers une approche modulaire pour la modification corporelle en temps réel en réalité augmentée
No full textInternational audienceVisual body modification in Augmented Reality (AR) offers new opportunities to study perception and embodiment. However, achieving real-time, egocentric body transformation remains technically challenging due to the need for accurate tracking, segmentation, and rendering. We present a modular AR platform designed for real-time visual hand replacement using video see-through displays. The system integrates six independent modules—video extraction, hand tracking, avatar animation, segmentation, hand erasing, and rendering—communicating via shared memory for low-latency processing. Each module supports multiple implementations, allowing adaptability to different experimental goals. Our open-source platform enables controlled manipulation of hand appearance, supporting perceptual and behavioral studies involving body image and interaction
Semi-Supervised Deep Learning Models for Automatic Identification of Benthic Fauna
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Experimental Procedures for Mixed-Mode Fracture Testing of Bonded Beams Using a Dual-Actuator Load Frame
No full textInternational audienceExperimental Procedures for Mixed-Mode Fracture Testing of Bonded Beams Using a Dual-Actuator Load Fram
Analyse et reconception d'une séance d'enseignement en Sciences de l'Ingénieur en classe de CPGE TSI.
No full textInternational audienceAnalyse et reconception d'une séance d'enseignement en Sciences de l'Ingénieur en classe de CPGE TSI
Kernel-Based Machine Learning Surrogates for RF Circulator Design
No full textInternational audienceMachine learning has attracted significant interest in the microwave community in recent years. It has the potential to greatly enhance design flows, but the choice of the algorithm and, more importantly, of the deployment strategy are nontrivial and may seem intimidating with respect to traditional approaches. This paper is intended as a proof of concept. It demonstrates a simple, effective, and elegant way to build and use feature-based surrogate models in order to improve the design process of RF circulators. The models are able to predict key metrics of the frequency response of the device, depending on its geometry. These models are then used to select configurations that meet the desired specifications
Defining a recommendation system to configure personalized assistance for individuals with cognitive impairments due to a traumatic brain injury
No full textInternational audienceSmart assistive technologies are increasingly being used to support independent living. Occupational therapists perceive such technologies as useful to helping their clients become more independent in their everyday activities, particularly individuals having sustained a traumatic brain injury. However, adapting and configuring these technologies to meet each person’s individual needs remain challenging. In this study, occupational therapists and computer scientists collaborate to develop a recommendation system designed to assist in configuring a smart assistive technology that helps people having sustained a traumatic brain injury cook safely. The relevance of the recommendations made by this case-based recommendation system was first evaluated by comparing the recommended assistant options with the selections of an expert occupational therapist. Then, we questioned the final users, i.e. occupational therapists, about the usefulness of such a system. This first prototype demonstrated promising results, with about 80% correct recommendations for selection (with an average percentage ranging from 77.0% to 86.2% depending on the threshold set for recommended functionalities, using a database of 16 cases). Additionally, the system was found to be robust against an unbalanced database and has been estimated as useful and relevant by end-users, who remain the final decision-makers. The latter also expressed concerns and suggested improvements, which were incorporated early in the development process to enhance acceptance and facilitate the tool’s integration into clinical practice. As a result, the tools and methods used by the multidisciplinary team led to the successful development of a generic human-centered recommendation system that can be used to personalize smart assistive technologies to each unique person’s needs
