HAL Portal Cnam (French National Conservatory for Arts and Crafts)
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Impact de modèles fluide et structure sur les vibrations induites par décrochage d'une pale d'éolienne à l'arrêt
No full textInternational audienceThis study aims at identifying the conditions that produce stall induced vibrations on a blade of the IEA15MW wind turbine at standstill. Several levels of modelisation are used and compared for both the aerodynamic and the structure in order to understand what is the impact of each model on SIV.Cette étude a pour objectif d'identifier les conditions produisant des vibrations induites par décrochage sur une pale de l'IEA15MW à l'arrêt. Plusieurs niveaux de modélisation fluide et structure sont utilisés et comparés afin de comprendre l'impact de chaque modèle sur ces vibrations
Influence of TimeGAN-Generated Scenarios on Optimal Design for Renewable Energy Systems
No full textInternational audienceThis study explores the influence of variability of natural resources and electrical consumption on the optimal biobjective design of isolated renewable energy microgrids. The variability is generated by synthetic time-series data produced by TimeGAN. The two primary objectives are to minimize the Levelized Cost of Energy (LCOE) and the Loss of Power Supply in Hours (LPSH). The approach integrates rule-based energy management and stochastic scenario variations of photovoltaic (PV), wind turbine (WT) production, and consumption profiles. The results demonstrate how variations in input scenarios impact the Pareto-optimal front, offering insights into system design robustness under uncertainty. The findings underscore the importance of addressing variability in renewable energy systems and pave the way for future work on stochastic optimization and multi-criteria decision-making for more resilient and sustainable energy solutions
Elaboration of novel biocomposite hydrogel polymers made of alginate and sepiolite and endowed with enhanced properties
No full textInternational audienceNowadays growing attention is given to the design and development of novel interpenetrating polymer networks (IPN) from the combination of hydrogel polymers loaded with natural clay. In this work, we used the eco-friendly IPN strategy to develop novel hydrogel biocomposite beads, made of alginate (ALG), with improved clay dispersion, higher pH sensitivity, better stretchability and swellability, together with enhanced regenerability properties and delayed biodegradability. Fibrous clay, namely, sodium sepiolite (NaS), was loaded into alginate simple biocomposite network (SBN) beads, via manual co-grinding mixture/encapsulation method, at different sepiolite loads. Alginate double biocomposite network (DBN) beads were also prepared at different sepiolite loads, via the diffusion of acrylamide monomers (AAM) inside alginate single biocomposite network (SBN) beads, followed by external and in situ free radical polymerization of AAM into polyacrylamide (pAAM), using ammonium persulfate (APS) as polymerization initiator and N,Nmethylenebisacrylamide (Bis) as covalent crosslinker agent. The as-elaborated SBN and DBN beads were then characterized by digital camera recording, XRD analysis, ATR-FTIR characterization and SEM observation. FTIR results showed that NaS and pAAM were successfully incorporated into DBN beads, while partially exfoliated morphology was obtained with XRD analysis, which revealed the enhancement of fibrous clay dispersion, even at relatively high sepiolite loads. Besides, SEM microscopy confirmed the porous spongious nature of DBN beads. The properties of the as-elaborated SBN and DBN beads were also evaluated by test touching, swelling rate measurements, adsorption/desorption experiments and biodegradability evaluation. DBN beads properties were always found enhanced in comparison with those of SBN beads. This suggests that the synergetic effect between IPN and biocomposite structure improves the stretchability of the DBN beads, their stability in water whatever the pH and their swelling behavior (up to 2000 g/g adsorbed water after 110 min, which was nevertheless found dependent on the pH and on sepiolite load). Moreover, DBN beads displayed enhanced adsorption/desorption properties Extended author information available on the last page of the article Polymer Bulletin toward methylene blue (MB) dye (no reduction in MB adsorption capacity after 5 cycles), very good regenerability (ethanol being used as effective eluting agent) and delayed biodegradability (complete degradation only after 8 days in the presence of sepiolite). In summary, this work showed an interesting and safe IPN/biocomposite approach to develop high-performance alginate biocomposite polymers as a promising system toward their use in eco-friendly processes.</div
Pourquoi choisir un niveau marin extrême «unique » ne fonctionne pas à l’île d’Yeu : quelle méthode pour l’évaluation des risques à l’île d’Yeu (085) ?
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Imagerie ultrasonore 3D par rayonnement de plaque mince appliquée à l'interaction homme-machine sans contact
No full textThe wide range of digital technology applications and the diverse contexts in which they are used drive the development of integrated multimodal interaction devices, enabling both tactile and contactless interactions with screens. This thesis contributes to this field through the development of a sensor for contactless gestural interaction based on the acoustic radiation of thin plates such as display screens. This radiation, controlled by a limited number of piezoelectric transducers coupled to the plate, is reflected by objects in the volume above and captured by microphones set in the plane of the plate. Using a 3D imaging technique based on unfocused ultrasound emission combined with tensor decomposition using HOSVD, this work achieved real-time imaging (33 Hz) of the volume (160 x 110 x 80 mm3) above the plate, with a spatial resolution of 1 mm. These advancements enabled first applications of detection and tracking of finger movements in air. Additionally, the hand movements generate a Doppler shift, which was utilized to identify 11 distinct 3D gestures performed by 19 participants. A low-complexity recurrent neural network was used to detect and classify these contactless gestures with no noticeable latency. In addition to contactless interaction, the methods developed in this thesis for fast imaging with a small number of transducers and Doppler pattern recognition open up new applications in medical imaging and non-destructive testing.La multiplicité des usages du numérique et la variété des contextes d'utilisation poussent au développement de dispositifs d'interactions multimodaux intégrés permettant une interaction tactile tangible ou sans-contact avec des écrans. Dans ce contexte, ces travaux de thèse ont porté sur le développement d'un capteur pour l'interaction gestuelle sans contact reposant sur le rayonnement acoustique de plaques minces, telles que des écrans. Ce rayonnement, contrôlé par un faible nombre de transducteurs piézoélectriques couplés à la plaque, est réfléchi par les objets du volume situés au-dessus et capté par des microphones placés dans le plan de la plaque. En s'appuyant sur une méthode d'imagerie 3D par émission ultrasonore non focalisée combinée à une décomposition tensorielle par HOSVD, ces travaux ont permis de produire une image en temps réel (33 Hz) du volume (160 x 110 x 80 mm3) au-dessus de la plaque avec une résolution spatiale de 1 mm. Ces résultats permettent de premières applications de détection et de suivi de déplacement de doigts dans l'air. Le mouvement des mains produit également un décalage Doppler qui a été exploité pour reconnaître 11 gestes 3D réalisés au-dessus de la plaque par 19 participants. Un réseau de neurones récurrent de faible complexité permet leur détection et classification sans latence perceptible. Au-delà de l'interaction sans contact, les méthodes développées dans cette thèse d'imagerie rapide à faible nombre de transducteurs et de reconnaissance de motifs Doppler ouvrent des perspectives d'applications en imagerie médicale ou contrôle non destructif
Reference Life Cycle Assessment of Smart Insoles with Piezoresistive Sensors for Motion Analysis
No full textInternational audienceThe environmental impact of wearable electronics is a growing concern. This study applies a Life Cycle Assessment (LCA) to smart insoles with piezoresistive sensors, comparing an experimental prototype (XP) to a commercial model (CO). Using a cradle-to-grave approach aligned with ISO 14040 and 14044, the analysis quantifies impacts across material extraction, manufacturing, transport, use, and end-of-life. The results indicate that XP insoles have a significantly greater environmental impact than the optimized CO models. Materials, particularly PDMS and electronic components, along with manufacturing energy, are the primary contributors to this outcome. Normalization and weighting identify key environmental hotspots, emphasizing the role of eco-design in enhancing sustainability
Exploring multidrug resistance patterns in community-acquired Escherichia coli urinary tract infections with machine learning
No full textInternational audienceWhile associations of antibiotic resistance traits are not random in multidrug-resistant (MDR) bacteria, clinically relevant resistance patterns remain underexplored. This study used association-set mining to explore resistance associations within E. coli isolates from community-acquired urinary tract infection isolates collected from 2018 to 2022 by France’s national surveillance system. Association-set mining was applied separately to extended-spectrum beta-lactamase-producing E. coli (ESBL-EC) and non-ESBL-EC. MDR patterns with expected support (reflecting pattern frequency) and conditional lift (reflecting association strength) higher than expected by chance ( P -value ≤ 0.05) were used to construct resistance association networks and analyzed according to time, age, and gender. The number of isolates increased from 360,287 in 2018 to 629,017 in 2022. More MDR patterns were selected in ESBL-EC than non-ESBL-EC (2022: 1770 vs 93 patterns), with higher respective network densities (2022: 0.301 vs 0.100). Fluoroquinolone, third-generation cephalosporin, and penicillin resistance were strongly associated in ESBL-EC. Median network densities increased from 2018 to 2022 in both ESBL-EC (0.238–0.301, P -value = 0.06, Pearson test) and non-ESBL-EC (0.074–0.100, P -value = 0.04). Across all years, median densities were higher in men than in women (ESBL-EC 2022: 0.305 vs 0.271; non-ESBL-EC: 0.128 vs 0.094) and higher in individuals over 65 than under 65 (ESBL-EC: 0.289 vs 0.275; non-ESBL-EC: 0.103 vs 0.088). These findings highlight temporal, age-specific, and gender-specific variations in resistance patterns, underscoring the potential of machine learning to understand them and inform antibiotic strategies
Peer-to-Peer Market and DSO Coordination Simulation on GPU
No full textInternational audienceThe energy transition requires increasing renewable energy production and consumer flexibility. These changes will likely take place in the distribution grid. In addition, consumer flexibility should be managed in a decentralized way to respect people’s privacy. Solutions for a decentralized market that can handle the physical transport state already exist in the literature. Nevertheless, these implementations are not suited for the distribution grid as they do not scale up well with the problem size when simulated on a single machine. In this contribution, we propose an endogenous Peer-to-peer market on a graphics processing Unit (GPU) to allow the scaling up of these algorithms. The algorithm relies on a consensus between a peer-to-peer market and the distribution system operator that solves an optimal power flow. As the bottleneck of this computation is the optimal flow, we used the speed-up brought by the GPU parallelization to conduct a study on significant test cases to gain time by modifying the interactions. It has been shown that if the coordination is poorly designed, it can prevent the computation from converging. Nevertheless, the average computation time in the European TestFeeder can be halved with a different coordination. The open-source framework of this article allows anyone to conduct a parametric study on their case
Communicating the risk of erosion: the effects of map-based communication on risk perception and affect
No full textInternational audienceThis study firstly aims to understand the impacts of map representations of coastal erosion on risk perception and affects of lay citizens. Secondly, it aims to study the effect of differing design of cartographic features on observation and interpretation of the message conveyed by different maps. Seven maps were presented to the participants (N = 50), varying according endogenous (abstraction, regalian cartridge) and exogenous characteristics (background, colours). A questionnaire interrogated risk perception and affect before and after observation, while eye-tracking data were recorded during the observation of each map. This experiment shows that communicating erosion risk by maps reduces perceived knowledge of risk but also reduces fear of the risk. The abstraction level significantly impacts observation patterns: correlation maps seem to guide visual attention in a more relevant way and to convey the message more clearly and effectively than other types of maps. But there is no influence of the other characteristics even if interviews show that colours seem to influence the message interpretatio
Static linking: pitfalls, harms and challenges
No full textInternational audienceA static library or a statically linked library contains functions and data that can be included in a computer program at build-time such that the library does not need to be accessible in a separate file at run-time. Static linking is an old concept that, during the 2000s, was considered a legacy approach and was gradually phased out in favor of dynamic libraries.Dynamic libraries offer significant advantages in code reusability, security, and memory efficiency. In contrast, static libraries provide potential speed optimization by reducing dead code and enabling seamless code integration without relying on API or ABI stability, including the application of custom patches to upstream code.In the 2010s, this seamless code integration became known by various terms, such as vendoring (Go terminology), packing, bundling, browserifying (JavaScript terminology), and uber-jar (Java terminology). At its essence, it represents a form of static linking, even within interpreted languages.The widespread use of static linking presents significant challenges for release managers and security managers. While some workarounds, such as Static-Built-Using package metadata, binNMU, or mass rebuilds, exist, they are often insufficient or overly cumbersome in practice.Moreover, following a Thompson-like argument, a Reflections on Static Trusting Trust approach should be undertaken from a security perspective to ensure the removal of insecure code. Practical assistance could be obtained from reproducible builds, though these lack theoretical guarantees.Introducing new concepts, such as Transiently Stable Dynamic Linking and leaf static linking, could help alleviate certain challenges and contribute to improving the current status quo.</p