HAL Portal Cnam (French National Conservatory for Arts and Crafts)
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Experimental and numerical investigation of laser intensity distribution influence on laser pressure loading
No full textInternational audienceLaser shock applications are numerous and various. They all require to know how pressure loading-due to laser irradiation-is influenced by laser parameters. This study aims at analyzing the influence of laser intensity distribution on pressure loading. This work presents the results from laser shots proceeded at LULI2000 on aluminum with LiF window targets. First, laser parameters are introduced and the radial distribution of laser intensity is estimated, thanks to a fourfold Gaussian distribution. Then, the experimental results and post-mortem samples are analyzed. Afterward, two methodologies to estimate the laser pressure loading-considering the laser intensity distribution-are described, applied, and compared. The first one with the monodimensional multi-physics simulation code ESTHER and the second one coupling the use of both ESTHER and the bidimensional (2D) hydrodynamics simulation code HESIONE [Aubert et al., J. Laser Appl. 31, 042014 (2019)]. The discussion presents the accuracy of these two methodologies regarding the experimental results. Comparison with a perfect top-hat laser intensity distribution highlights the edge effects. Finally, future possible works are suggested such as testing the methodology on other laser facilities or using a 2D/3D multi-physics simulation code
Machine learning et logements collectifs : quand l’algorithme rencontre la transition énergétique
No full textInternational audienceDepuis le début des années 2020, le secteur immobilier français est impacté par la hausse des coûts de construction et les nouvelles réglementations environnementales (RE 2020). Dans ce contexte, la valeur verte, définie comme l’augmentation du prix d’un bien immobilier liée à celle de ses performances énergétiques, devient un enjeu clé. Cet article, réalisé en collaboration avec le Groupe Vivialys, propose une méthode d’estimation de cette valeur à l’aide d’outils issus du machine learning sur des bases de données ouvertes portant exclusivement sur des logements collectifs. Les résultats menés lors de cette collaboration montrent que les logements plus performants énergétiquement bénéficient d’une revalorisation mesurable, offrant ainsi un outil d’aide à la décision pour les acteurs du marché immobilier
Impact of varying epoch length in accelerometry data processing on physical activity intensity classification in adults: considerations for public health
No full textInternational audienceImpact of varying epoch length in accelerometry data processing on physical activity intensity classification in adults: considerations for public health Preferred mode of presentation: poster ICDAM 2025 streams Data collection methods, including development, adaptation and validation Data analysis methods, including data sciences/AI</div
Burn-out militant: Comment s'engager sans se cramer
No full textInternational audienceMontée de l'extrême droite, backlash antiféministe, accroissement des inégalités, dérèglement climatique... Les causes à défendre ne manquent pas, et il y a urgence ! Aujourd'hui, les militants sont mis à rude épreuve. Car, que ce soit dans des associations de quartiers, de solidarité, de défense des droits ou écologistes, s'engager est souvent chronophage, coûter émotionnellement, bref épuisant. Les burn-out n'est pas réservé au monde du travail. Les milieux militants connaissent aussi leur lot de personnes et de collectifs qui s'arrêtent, épuisés. Alors comment se protéger et protéger les autres ? Comment faire en sorte que celles et ceux qui s'engagent continuent à (tenter de) changer le monde sans s'esquinter la santé ? Véritable guide pour militer sans se cramer, ce livre vise à aider les personnes et les collectifs qui s'engagent à éviter la surchauffe
Recension de l’ouvrage de Nicolas Roux, La précarité durable. Vivre en emploi discontinu
No full textInternational audienceIntroduction Dès le titre de l’ouvrage, Nicolas Roux annonce le paradoxe qu’il souhaite interroger : comment un enchaînement de contrats courts peut-il être accepté et supporté par des individus alors même que dans certains secteurs, il ne constitue ni un sas vers la stabilité en emploi, ni la conséquence d’une chute sociale, mais devient la norme ? L’auteur reprend ainsi son travail de thèse (2017) pour explorer comment les salarié·es, premier·ères concerné·es, vivent cette précarité durabl..
Functional Interval Observers‐Based Fault‐Tolerant Control for Linear Parameter‐Varying Systems
No full textInternational audienceThis study deals with passive Fault Tolerant Control (FTC) based on Functional Interval Observers (FIO) for Linear Parameter‐Varying systems. First, positive systems theory is used to design an asymptotic FIO, giving the upper and lower bounds of the state variable function. Next, an norm‐based method is proposed to attenuate the effect of uncertainties and to improve the accuracy of the proposed observer. Then, a FIO‐based FTC law is designed to reduce the fault effect and stabilize the closed‐loop system based on an index. Stability conditions are expressed in terms of Linear Matrix Inequalities. Finally, a simulation example is given to verify the effectiveness of the proposed techniques
Observing the Yardang unit at Gale crater on Mars with ChemCam’s RMI
No full textInternational audienceThe Remote Microscopic Imager (RMI) of the ChemCam instrument onboard Curiosity rover provides high-resolution imaging capabilities [1,2]. RMI was first designed to document the LIBS analysis on rocks and soils located at few meters from the rover. RMI progressively proved also to be a powerful long distance imaging reconnaissance tool, thanks to its 700mm focal length. In particular, a new software was uploaded in 2015 to automatically focus up to infinity, a capability which was not implemented in the original design [3]. Since then, RMI has been regularly used to investigate distant various landscapes. Among these, the so-called « Light-toned Yardang unit » [4] was first observed beginning sol 1183 (Figure 1). Several RMI image mosaics acquired up to Sol 1998 helped to identify successive sequences of aeolian deposition-erosion. This is among the youngest sedimentary layers that can be observed in Gale crater with Curiosity cameras. It is interpreted as a succession of fossil aeolian dunes and deflation surfaces [4, 5]. The Yardang unit could result from cyclic changes from semi-arid to arid conditions, including wind regime changes. No hydrated mineral has been detected from orbital imaging spectroscopy. Still, there is interest in finding out the role that water may have played in the induration and diagenesis of the rocks that make up this Yardang unit[5].Between Sols 3671 and 4389, several new long distance RMI mosaics have been acquired while pointing at the base of the Yardang unit. The closer vantage point helps to identify multiple morphologies such as fine-scale layering, wind erosion patterns, or scallops. These features were not accessible nor resolved from orbital imagery only. They could shed light on the formation process of this massive unit. Figure 2 shows an example of a 10800x3200 pixels mosaic corresponding to an assemblage of 60 individual RMI frames which were acquired during three 20x1 sequences between Sols 4384 and 4389.Curiosity has already driven 34 km since the landing in 2012. If Curiosity ever reaches the base of the Yardang unit [6], it would provide the opportunity to sample it directly and reveal its bulk composition, in addition to deriving information from distant geomorphological investigations
De l’accompagnement numérique à la coproduction de l’accès aux services publics : le cas des conseillers France services
No full textInternational audienceThe dematerialisation of public services has led to an increase in the rate of non-use of entitlements. In response, the French government has created the new job of "Conseillers France Services" to help users with their day-to-day administrative procedures. This support consists of co-production mediated by the digital tools of public administrations. First, the analysis of the work of the CFS has highlighted a diversity of support situations resulting from the variability of users, their requests, the associated procedures and the tools to be used. Then, the activity of the CFS, analysed through the prism of the capabilities, was considered as the creation of an enabling environment for users, thus opening up prospects for the recognition and development of the CFS profession.La dématérialisation des services publics a augmenté le taux de non-recours aux droits. En réponse, l’État a créé le nouveau métier de Conseiller France services pour accompagner les usagers dans leurs démarches administratives quotidiennes. Cet accompagnement consiste en une coproduction médiée par les outils numériques des administrations publiques. L’analyse du travail des CFS a d’abord mis en lumière une diversité de situations d’accompagnement résultant de la variabilité des usagers, de leurs demandes, des procédures associées et des outils utilisés. Puis, l’activité des CFS a été analysée au prisme des capabilités, et considérée comme la création d’un environnement capacitant pour l’usager, ouvrant ainsi sur des perspectives pour la reconnaissance et le développement du métier de CFS