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Modélisation et visualisation de la progression des compétences : une intégration sémantique de graphes pédagogiques et d'IA générative
No full textInternational audienceIn the field of pedagogical engineering and competency management, modeling learning paths explicitly is essential for personalizing training and guiding educational decisions. This work proposes an integrated approach that combines semantic and graphical representations of competencies with generative AI to enhance the interpretation of learning paths. Competencies are modeled as nodes in a lightweight ontology derived from structured frameworks (e.g., ROME, ESCO), with links representing pedagogical relationships such as prerequisites or complementarities. Learner profiles are visualized dynamically to reflect competency acquisition and guide optimal progression. Generative AI enriches this graph by generating contextualized descriptions, annotating resources, and suggesting related competencies to expand learning trajectories. This approach improves the clarity of training pathways, supports adaptive learning, and fosters more strategic use of competency frameworks, contributing to the development of explainable, interoperable learning systems
Le projet 4BLife : intégrer le vieillissement des batteries dans le dimensionnement et la gestion des micro-réseaux
No full textInternational audienceThis paper presents the results of the 4BLife project, which aims to integrate aging laws into the sizing and management of storage systems using lithium-ion batteries. This involves defining one or more aging models as well as tools for performance characterization and State of Health (SoH) monitoring. Laboratory and field data are used to identify aging models and validate SoH tracking tools. Two battery technologies, LFP and NMC, suitable for both embedded and stationary applications, are studied. The integration of aging laws into the design and management of stationary storage systems is explored through simulation. The validation of aging impacts under real-world operating conditions is currently under investigation.Ce papier présente les résultats du projet 4BLife dont l'objectif est d'intégrer des lois de vieillissement dans le dimensionnement et la gestion de dispositifs de stockage utilisant des batteries lithium-ion. Cela nécessite de définir une ou plusieurs lois de vieillissement ainsi que des outils de caractérisation de performances et de suivi de l'état de santé (SoH). Des données en laboratoire et de terrain sont exploitées pour identifier les modèles de vieillissement et valider les outils de suivi de SoH. Deux technologies de batteries LFP et NMC aptes à fonctionner en condition embarquée et stationnaire sont étudiées. L'intégration de lois de vieillissement dans le dimensionnement et la gestion de systèmes de stockage stationnaire est abordée par la simulation. La validation des impacts sur le vieillissement des batteries en condition réelle est en cours d'étude
Singularities and Regular Correction for Elliptic Problems with Non-Constant Coefficients and Dirac Sources on the Boundary
No full textWe focus on the singularity of the potentials generated by Dirac sources located on the boundary. The diffusivity parameters of the medium are non-constant. We present and prove a singular/regular expansion of these potentials, following a prediction-correction approach. The singularity is made explicit using the fundamental Green's kernel of the Laplace operator. The regular correction problem can be efficiently solved using classical finite element methods. A numerical discussion highlights the relevance of this approach in achieving significant accuracy.</div
Elucidating the modulation of oat starch-protein complex molecular structure and starch digestion under microwave field treatment
No full textInternational audienceThe effects of microwave (MW) and water bath (WB) treatments on the physicochemical properties and digestibility of oat protein-starch complexes were investigated. The textural and rheological results indicated that the MW treated group exhibited greater hardness, elasticity, and cohesiveness, as well as higher G′, G″, and apparent viscosity. The results of Fourier transform infrared spectroscopy and X-ray diffraction revealed that the rapid heating by MW promoted the formation of hydrogen bonds, more stable double-helix structures, and ordered structures, thereby enhancing starch-protein complex formation. SEM further validated these findings, showing that the gel network structure formed under MW treatment was denser and more stable, which resisted enzymatic hydrolysis. Starch digestion and LOP-CPS kinetic fitting results demonstrated a slower starch digestion rate in the MW treated group. Confocal laser scanning microscope analysis of the starch-protein interactions during digestion revealed that the physical barrier formed around the starch matrix hindered the binding of starch to amylase, making the starch less susceptible to hydrolysis. Therefore, MW treatment enhanced the gel structure of starch-protein complexes while decreasing their digestibility, positioning it as a promising approach for the development of slow-digesting foods
SiC MOSFET turn-off overvoltage measurement
No full textInternational audienceSelecting the appropriate measurement system is crucial in power electronics. This is especially important during MOSFET's turn-off process, where it is essential to measure the voltage rise and accurately capture the peak overvoltage. During turn-off, the interaction between the MOSFET and the parasitic element of the PCB creates a resonance. This phenomenon leads to an overvoltage, which peaks at the resonance frequency and can potentially damage the device. This paper discusses the characteristics of the measurement system needed to capture the peak overvoltage accurately. A step-by-step guide is proposed to ensure the correct selection of the probe and its correct use. This guide is experimentally validated on a three-level converter, where drain-source voltage measurements have been performed with and without a ground reference. The drain to source measurement method proposed in this paper is accurate, costeffective and capable of minimizing induced noise
Using SiC JBS diode as voltage clamping in SSCB application: performances and limitations
No full textInternational audienceThe performances and limitation of SiC JBSdiodes used as clamping devices for SSCB havebeen investigated trough simulation andexperimental measurements. The simulationsevaluations are based on CAD and electro-thermal circuit modelling of packaged devices.The simulations have been done on a wideblocking voltage range, form 80V to 1.7kV. Anoptimal trade-off in terms of layout and avalanchecapability has been found. A failure criterion interms of power density has been established,linked to device top metal layers melting (around500°C) and measured on commercial devices.Avalanche to Nominal current Ratio variesbetween 6 up to 10 depending on themanufacturer. A LTspice electro-thermal modelallows to predict the required SiC devices area toachieve specific performances. Finally, ademonstrator of 1.2kV-2x50A-SOT227 SiC JBSclamping diode is presented
Investigations on Phase-Modular PFC with Integrated DC-Link Energy Buffer for On-Board Battery Chargers
No full textInternational audienceIn this paper a two-stage bidirectional Power FactorCorrection (PFC) boost-buck topology featuring a novelbuilt-in energy storage buffer functionality is proposed,specifically tailored for (isolated) On-Board Charger(OBC) applications. Main concept idea is to allow acertain amount of voltage oscillation at twice the linefrequency at the output of the boost PFC stage (allowinga significant reduction of the dc-bus capacitor), and letthe cascaded step down converter, namely the SeriesConnected Buck-type (SCB) Pulsating Power Buffer(PPB), to dynamically absorb the pulsating energy,aiming at supplying a stiff voltage for the multi-portDC transformer (DCX) stage feeding the battery. Thetopology incorporates modular single-phase totem-pole(TP) modules that deliver 3.6 kW each in a three-phaseset-up, or can be configured in parallel for single-phaseoperation at 2.4 kW each, resulting in total output powersof 11 kW and 7.2 kW, respectively. The proposed activebuffer solution allows enhancing the power density ofthe system, by minimizing the capacitor size, and makesuse of varied semiconductor devices with breakdownvoltages of 750 V and 1.2 kV. A Multi Objective Optimization (MOO) process is adopted to seek for the mosteffective balance between bulk capacitance and inductivecomponents against losses and switching frequencies,thus achieving peak power density. Comprehensive analytical and simulation results are shown to validate theeffectiveness of the proposal, together with a sketch ofthe actual experimental prototype
Cost and Efficiency Optimization for a Reconfigurable E-Bike Battery System for EPE'25
No full textInternational audienceThis study optimized and evaluated the module voltage level of an e-bike's reconfigurable battery system for efficiency and costs against a conventional powertrain. For micromobility applications, findings indicate that with today's semiconductor switches, these systems remain less competitive than a conventional, two-level inverter powertrain, with a 5% efficiency and 18% cost disadvantage
Energetic Properties of the Fast Charging and Driving of an Electric Vehicle -A Ragone Analysis
No full textInternational audienceThe energy efficiency of EV's is analysed for the charging and for the driving process where real parameters of a product of the automotive industry are considered. The efficiency in the charging mode is analysed and represented in function of the charging time. The maximum charging power allowed by the manufacturer is defining the lowest efficiency. After the calculation in a situation with an ideal charging station the influence of the resistance of the charging cable is taken into consideration. For the driving mode, the efficiency is estimated with the help of a special tool called "The Theory of Ragone plots". The driving efficiency is calculated for the maximum possible propulsion power of the car and is represented in a dimensionless Ragone representation. The rated power of the car is represented in reference to the maximum possible power that can deliver the car battery
