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Undercut error and compensating trajectory simulation versus experiments comparison when contour turning of Inconel 718 thin-walled parts
No full textInternational audienceWhen machining thin-walled parts, one of the main sources of deformation is bending under the effect of cutting forces. This phenomenon generates an undercut defect that can lead to alterations in the dimensions of the finished part. In practice, this problem requires a long and costly iterative trial-and-error loop to be corrected. The solution is not always obvious, as it may involve either modifying the machining parameters, the tool path or the machining fixture. To anticipate these difficulties and help in the decision-making process when developing machining sequences, the use of simulation is of interest. Initially, the aim of this study is to compare the geometric defect measured during machining trials and predicted by simulation. The tests were carried out by turning thin Inconel 718 parts, the geometry of which is a representative portion of a turbine disc. In simulation, a model representing the part's flexibity is coupled to a model that aims to predict the cutting forces applied. Secondly, a strategy is proposed for defining a compensating trajectory by simulation, with the aim of minimising the geometric defect. The geometric defect is measured after a test using this compensating trajectory. The results show a promising correlation between simulation and experimental testing, and point the way to improvements that will lead to a broader scope of validity
Intelligence artificielle et blockchain pour la gestion décentralisée de l'énergie dans une communauté énergétique de bâtiments intelligents
No full textThe development of collective self-consumption communities, where local actors share renewable energy and flexibility, requires new decentralized energy management approaches. This thesis focuses on the design and implementation of intelligent and distributed control strategies for managing local photovoltaic production, consumption, and storage within a real-life energy community.The first part introduces a forecasting framework based on LSTM neural networks to predict short-term energy production and demand using historical data from a smart grid demonstrator. These forecasts guide decisions in a multi-agent energy management system, where each agent—representing a building, an electric vehicle, or a storage unit—optimizes its energy usage according to individual preferences, balancing cost, comfort, and the use of local renewable energy. Three coordination strategies are investigated: rule-based control, ADMM optimization, and market-based negotiation between agents.The influence of forecast uncertainty is analyzed through week-long simulations comparing predicted and real data. Results demonstrate the sensitivity of decentralized coordination strategies to prediction errors and underline the trade-offs between robustness and performance.Finally, the complete system is deployed on Raspberry Pi devices and connected to a user-friendly simulation platform developed with Streamlit. This setup integrates forecasting, optimization, and blockchain-based energy exchange via smart contracts, enabling secure, transparent, and autonomous operation without relying on a central authority.Overall, this modular and scalable architecture provides a realistic, accessible, and privacy-preserving framework for enabling intelligent energy communities and supporting the energy transitionLe développement des communautés d’autoconsommation collective, où des acteurs locaux partagent énergie renouvelable et flexibilité, nécessite de nouvelles approches de gestion décentralisée de l’énergie. Cette thèse s’intéresse à la conception et à la mise en œuvre de stratégies de contrôle intelligentes et distribuées pour gérer la production photovoltaïque, la consommation et le stockage au sein d’une communauté énergétique réelle.La première partie propose un cadre de prévision basé sur des réseaux de neurones LSTM afin d’anticiper la production et la demande d’énergie à court terme à partir de données historiques issues d’un démonstrateur de réseau intelligent. Ces prévisions orientent les décisions dans un système de gestion multi-agents, où chaque agent — représentant un bâtiment, un véhicule électrique ou une unité de stockage — optimise son usage énergétique selon ses préférences individuelles, en arbitrant entre coût, confort et utilisation des énergies renouvelables locales. Trois stratégies de coordination sont étudiées : le contrôle par règles, l’optimisation ADMM et la négociation de type marché entre agents.L’influence de l’incertitude des prévisions est analysée à travers des simulations sur une semaine complète, comparant données prédites et données réelles. Les résultats mettent en évidence la sensibilité des stratégies de coordination décentralisée face aux erreurs de prévision, ainsi que les compromis entre robustesse et performance.Enfin, l’ensemble du système est déployé sur des Raspberry Pi et connecté à une plateforme de simulation conviviale développée avec Streamlit. Cette configuration intègre prévision, optimisation et échanges énergétiques basés sur la blockchain via des contrats intelligents, permettant un fonctionnement sûr, transparent et autonome sans autorité centrale.Dans son ensemble, cette architecture modulaire et évolutive propose un cadre réaliste, accessible et respectueux de la vie privée pour le déploiement de communautés énergétiques intelligentes et l’accélération de la transition énergétiqu
Fostering the cultural heritage exhibition co-design process: a scientific and industrial perspective
No full textInternational audienceIn recent years, the museum sector has faced new ethical and social challenges, including public inclusion, content accessibility and ecological responsibility. In order to address these challenges, the use of interactive museum installations (IMI) has emerged as a potential solution for a new form of mediation. However, this shift in the mediation process necessitates a corresponding evolution in design practices and methodologies. To facilitate this development, this study proposes to characterise and formalise the challenges encountered in the sector from the point of view of methodological tools. To this end, this study proposes a systematic literature review to establish the academic challenges that remain to be met. To provide a comprehensive evaluation, a sectoral workshop was analysed to assess the impact of resolving these issues. Ultimately, interviews with professionals in the sector have facilitated a more comprehensive examination of the question of implementing design tools in applied processes. This analysis has facilitated the identification of the challenges that must be addressed to introduce methodological contributions to this particular co-design process
Enhancing dental model accuracy through optimized vat photopolymerization additive manufacturing parameters
No full textInternational audienceThis study investigates the key additive manufacturing (AM) process parameters that influence the dimensional accuracy of dental models produced using the vat photopolymerization Digital Light Processing (DLP) technology. By applying the Taguchi method, 7AM process factors were analyzed. A standardized post-processing protocol was used to maintain consistency, allowing a focused assessment of the printing parameters. Dimensional deviations were analyzed using 3D scanning and point cloud comparison software, with particular attention to reducing warping and shrinkage. The results identified layer thickness, projector power, exposure energy, and vat temperature as the key AM factors affecting the accuracy of the final model. These findings highlight the importance of optimizing these parameters to achieve high-quality dental models, contributing to future advancements in precision and efficiency. Further research is recommended to determine optimal settings for different resins and more complex dental structures
EDUCAUSE 2024 French and Japanese Delegation Joint Report - EN: Visits to Houston Community College, Texas A&M University, San Antonio College, University of Texas at San Antonio
No full textThe Annual Conference 2023 held in Chicago in October marked the 10th anniversary of the EDUCAUSEFrench Delegation. This milestone is obviously an opportunity for us to look back on the road travelled in adecade.From the beginning, this initiative has sought to provide the French higher education community with aninternational perspective on digital issues, by bringing together complementary profiles capable of assessing themajor trends and prospects. This has taken the form of ongoing participation in the EDUCAUSE AnnualConferences since 2013, which has been significantly enriched over the years. From an initial philosophy ofsimple participation that prevailed in the early years, the members of this Delegation have gradually becomeinvolved at various levels of EDUCAUSE, within the framework of the conferences and beyond (see theinfographic below).We have now twenty presentations selected on a range of topical subjects. Several of our members are alsoinvolved each year as proposal reviewers for the EDUCAUSE Annual Conference, and as members of therespective program committees (in 2019 and 2023). Finally, some of us sit on expert panels for the EDUCAUSEHorizon Report and the annual Top-10 issues, are active in various thematic Community Groups (XR andLearning Spaces in particular), or are involved as writers of reference articles and translators of tools.We should also mention the nearly thirty site visits that have also been carried out since 2013 before or after theEDUCAUSE Annual Conferences, which, in addition to the remarkable welcome we have always received, haveprovided us with an invaluable insight into the field through high-quality discussions
Maritime piracy bibliometric analysis: A literature overview and map review
No full textInternational audienceAbstract Maritime piracy represents a significant international challenge, impacting both economic stability and political dynamics. Researchers from diverse disciplines have been drawn to this multifaceted issue, each aiming to understand and address different aspects of piracy’s impact and implications. This study offers a comprehensive overview of maritime piracy research based on bibliographic analysis. Its objective is threefold. First, to delineate the key domains of inquiry within maritime piracy research. These domains encompass a wide range of topics, including the socio-economic drivers of piracy, the legal frameworks governing maritime security, and computer science to analyse piracy acts. Second, to identify major contributions in the field, recognising seminal works, influential authors and significant findings related to maritime piracy. Lastly, to discern emerging research trends within maritime piracy, and to identify novel areas of inquiry, innovative methodologies and promising avenues for future exploration. Furthermore, the most popular datasets from these studies that include relevant information are presented in this work
What You See is What You Get: Exploring Novel Hands-Free Methods of Virtual Body Control for Avatars
No full textInternational audienceDespite the growing interest in making Virtual Reality (VR) applications more accessible to users with impairments, VR accessibility still remains critical. In the context of shared virtual environments where users are represented by an avatar, controlling and animating in real time this virtual body can be especially challenging for users that suffer from paraplegia or other impairments that strongly reduce mobility. This paper thus aims to explore new control modalities over an avatar in VR involving extremely little or no movement at all of users’ physical body. We conducted an experiment in which healthy participants (n=24) could control a virtual body via head and eye-gaze interaction methods in a manipulation and a navigation tasks. Results indicated good usability scores with both methods and elicited a satisfying level of agency, while the workload constructs were significantly influenced by the interaction modality and the type of task carried out
Refining Research in Gameful Design
No full textInternational audienceTransforming daily chores into game-like activities has long been a tantalizing promise. Whether it is completing homework, washing dishes, or even filing taxes, many of these tasks have been incorporated into serious games or gamified interventions. Yet, the question remains: why do such efforts often fall short, leaving mundane tasks as unappealing as ever? In this article, we argue that the literature on game interventions could benefit from a methodological shift to better understand the impact of game mechanics on human psychology. We illustrate this point by presenting two experimental protocols that isolate game elements, providing a clearer understanding of their effects on the desired outcomes. The results of both studies are not disclosed here, as our focus is solely on the protocols themselves
Modélisation par poutre équivalente anisotrope des hydrofoils composites : du couplage fluide-structure vers l'optimisation des performances hydrodynamiques
No full textIn sailing conditions, foils are subjected to significant hydrodynamic forces and, as a result, undergo substantial deformation. This thesis focuses on the optimization of flexible foil designs made from composite materials, which, under certain conditions, exhibit a bending-torsion coupling that affects the angle of attack of a deformed foil. This thesis presents a methodology for numerically estimating and optimizing the performance of a flexible hydrofoil. The numerical model used in this work couples an equivalent beam model developed in AbaqusTM with a potential flow code, PUFFIn. Two experimental campaigns are conducted to validate the numerical models: the first in air, to validate the equivalent beam model, and the second in the current tank at Ifremer in Boulogne-sur-Mer, enabling the validation of the coupling between PUFFIn and AbaqusTM. This model is then used to optimize the structure and geometry of a flexible hydrofoil. Finally, the thesis presents a validation of the numerical tools developed, with the aim of moving beyond the use of the commercial software AbaqusTM.En navigation, les foils sont soumis à d’importants efforts hydrodynamiques et, en conséquence, se déforment de manière significative. Cette thèse s’intéresse à l’optimisation de designs de foils souples en matériaux composites, qui dans certaines conditions, sont caractérisés par un couplage flexion-torsion influant sur l’angle d’attaque d’un foil déformé. Cette thèse présente une méthodologie pour estimer et optimiser numériquement les performances d’un hydrofoil souple. Le modèle numérique retenu dans cette thèse est un couplage entre un modèle de poutre équivalente développé dans AbaqusTM et un code fluide parfait, PUFFIn. Deux campagnes expérimentales sont réalisées pour valider les modèles numériques. Une première en air pour valider le modèle de poutre équivalente et une seconde dans le bassin de courant de l’Ifremer de Boulogne-Sur-mer, permettant la validation du couplage entre PUFFIn et AbaqusTM. Ce modèle est ensuite exploité pour optimiser la structure et la géométrie d’un hydrofoil souple et pour finir, une validation des outils numériques développés dans cette thèse, ayant pour but de s’affranchir du logiciel commercial AbaqusTM, est présentée
Contrôle grid-forming pour la restauration du système de transmission à partir du réseau de distribution
No full textThe increasing penetration of renewable energy sources and the decentralization of power generation are reshaping the roles of transmission and distribution networks in system op-eration and restoration. This thesis explores the contribution of power converters in the distribution network to MV and HV system restoration. A key objective of this work isthe development of a converter control capable of autonomously energizing transformersand grid sections while ensuring current limitation and system stability. The thesis begins with a theoretical foundation on Grid-ForMing control (GFM), including current limitation techniques and stability analysis under large disturbances. It then proposes a virtual power-based method to enhance large disturbance stability of GFM. The proposed solutions are then extended to unbalanced conditions and MV applications, and validated experimental lyacross various fault scenarios. Then, the work addresses direct transformer energization,analyzing inrush current behavior and demonstrating how the developed GFM can miti-gate these effects while maintaining stable operation. Subsequently, the thesis presents adistributed blackstart scenario on a distribution network benchmark. The aim is to demon-strate a sequential re-energization from the distribution system up to the transmission grid,while maintaining voltage quality and respecting converter limitationsL’intégration croissante des énergies renouvelables et la décentralisation de la production sont en train de redéfinir le rôle des réseaux de transport et de distribution dans l’exploitation et la restauration du système. Cette thèse étudie la contribution des convertisseurs de puissance dans le réseau de distribution `a la restauration des réseaux de moyenne et haute tension. Un objectif central de ce travail est le développement d’une commande de convertisseur capable de mettre sous tension de manière autonome des transformateurs et des sections de réseau,tout en assurant la limitation du courant et la stabilité du système. La thèse débute par une base théorique du contrôle Grid-Forming (GFM), incluant les techniques de limitation de courant et l’analyse de la stabilité lors de fortes perturbations. Elle propose ensuite une méthode de puissance virtuelle visant à améliorer la stabilité du GFM en régime de grandes perturbations. Les solutions proposées sont étendues aux conditions d´déséquilibrées et aux applications en moyenne tension, puis validées expérimentalement sur différents scénarios de défaut. Le travail s’intéresse ensuite `a la mise sous tension directe de transformateurs, en analysant le comportement du courant d’appel et en montrant comment le GFM développé peut en atténuer les effets tout en maintenant un fonctionnement stable. Enfin, la thèse présente un scénario de blackstart sur un réseau de distribution. L’objectif est de démontrer un redémarrage séquentiel du réseau de distribution jusqu’au réseau de transport, tout en garantissant la qualité de la tension et en respectant les limites des convertisseurs