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Multi-Objective PSO for the Sizing of a 12-Pulse Diode Rectifier: A Comparative Analysis at Room and Cryogenic Temperatures
No full textInternational audienceThis paper compares the optimal sizing of a 12pulse diode rectifier operating at room temperature (293 K) and at cryogenic temperature (77 K). First, a diode database is constructed from diode measurements at both temperatures. Then, using the PSO (Particle Swarm Optimization) algorithm, the converters are sized to maximise efficiency and minimise volume. The results show that the converter designed to operate at 77 K achieves efficiency levels comparable to those at 293 K (without cooling penalty). However, the cryogenic design offers significant volume advantages over the room temperature design, making it particularly beneficial for applications where volume and weight are limited
Vers une éco-conception proactive : État de l'art sur le développement de produit et perspectives de recherche
No full textInternational audienceVers une éco-conception proactive : État de l'art sur le développement de produit et perspectives de recherch
Explorer l'architecture des jumeaux numériques : Rôle, définition et état de l'art
No full textInternational audienceExplorer l'architecture des jumeaux numériques : Rôle, définition et état de l'ar
Unmixing Mean Embeddings for Domain Adaptation with Target Label Proportion
No full textWe introduce a novel approach to domain adaptation within the context of Learning from Label Proportions (LLP). We address the challenging scenario where labeled samples are available in the source domain, but only bags of unlabeled samples with their corresponding label proportions are accessible in the target domain. Our proposed method, bagMME (Bag Matching Mean Embeddings), tackles the distributional shift between domains by focusing on matching class-conditional distributions. A key contribution of bagMME is a simple yet effective unmixing strategy that leverages the target label proportions to estimate the target class-conditional mean embeddings. These estimated target means are then aligned with their corresponding source class-conditional means, thereby reducing the domain discrepancy. We theoretically demonstrate the soundness of our approach and its effectiveness in mitigating distributional shifts. Extensive experiments on various computer vision datasets, including Office-31, Office-Home, VisDA-2017, and digit datasets, showcase the superior performance of bagMME compared to state-of-the-art baselines. Our results highlight the critical role of incorporating target label proportions into the learning process for improved generalization on the target domain.</div
Cathelicidin-BF: A Potent Antimicrobial Peptide Leveraging Charge and Phospholipid Recruitment against Multidrug-Resistant Clinical Bacterial Isolates
No full textInternational audienceCathelicidin-BF (CatBF) is a LL-37 homologous antimicrobial peptide (AMP) isolated from Bungarus fasciatus with an exceptional portfolio of antimicrobial, antiviral, antifungal, and anticancer activities. Contrary to many AMPs, it showed a good pharmacological profile with a half-life of at least 1 h in serum and efficacy against bacterial infections in mice. To evaluate its potential against resistant nosocomial infections, we assessed its activity against 81 clinically relevant resistant bacterial isolates. CatBF exhibited minimum inhibitory concentrations (MICs) as low as 0.5 μM against carbapenem-resistant Acinetobacter baumannii, Klebsiella pneumoniae, and Escherichia coli. Its wide-ranging activity, unaffected by resistance mechanisms or Gram phenotype, prompted us to investigate its molecular mode of action. NMR spectroscopy, paramagnetic probes, and molecular dynamics (MD) simulations were employed to define its structure, penetration depth, and orientation in various membrane models, including micelles, bicelles, oriented bilayers, and vesicles. We found that CatBF's potent activity relies on its strong charge, allowing membrane neutralization at low peptide/lipid ratios and selective recruitment of charged phospholipids. At higher concentrations, a change in peptide orientation reveals membrane invagination and the formation of transient pores possibly leading to bacterial death. Our findings highlight the potential of CatBF as a model for developing resistance-independent agents to combat multidrug-resistant (MDR) bacterial infections
Modulation of textural properties in microwave treated gluten-free quinoa sponge cake by alkaline amino acids
No full textInternational audienceLysine (Lys) and Arginine (Arg) (0.6%) was added to the quinoa flour to improve the textural quality and physical properties of gluten-free sponge cake treated with different heating methods. The gluten-free sponge cake fortified Lys and Arg increased cell density and surface area fraction, compared to water bath (WB) treatment, with the microwave (MW) treatment further enhancing these effects. Furthermore, MW combined Lys treatment showed the best texture characteristics of sponge cake. The water distribution determined by 1H NMR presented that water molecules are bound by the protein network structure. FTIR spectrum proved MW combined with Lys promoted the transition from disordered structure to ordered structure of protein in quinoa sponge cake, which enhanced the expansion of protein molecules and the exposure of hydrophobic regions, thus promoting protein aggregation. SDS-PAGE revealed when alkaline amino acids were present, they can regulate the ordered aggregation of protein molecules under MW alternating electric field, leading to enhanced intermolecular interactions. Finally, microstructure evaluations by SEM demonstrated MW combined with alkaline amino acids formed a stable three-dimensional gel network structure, thus improving the quality of gluten-free quinoa sponge cake. Therefore, the study findings pointed to the feasibility of using MW to improve the physical and textual quality of quinoa gluten-free food
Analysis of imbalanced data from porosity measurements on high-pressure hydrogen vessel (Type IV)
No full textInternational audienceOur research focuses on the critical role of porosity in composites used for high-pressure hydrogen storage vessels (HPV), highlighting its negative impact on safety and performance of the HPV. Poorly controlled porosity compromises the vessel's mechanical integrity and increases the risk of premature failure.In this study, we employed X-ray tomography to visualize, locate, and quantify porosities in these vessels. The objective was to link processing parameters, specifically filament winding, to the porosities observed. Since the tomographic measurements were performed on entire vessels, we are faced with a small dataset, with significant imbalances in the number, size, and volume of the porosities.To improve our analysis, we implemented advanced data processing methodologies to handle the industrial datasets. Specifically, we identified a significant imbalance between defect classes in the data from the manufacturing and testing of type IV hydrogen vessels. This asymmetry complicates the analysis and prediction of results. To overcome this, we evaluated and compared methods such as Weighted Logistic Regression, Weighted Decision Trees, and the Discrete Minimax Classifier (DMC) which adapt their strategies to improve the detection of minority classes and enhance the classification of porosity-related data. These techniques help identify the most critical defects while accounting for the data imbalances.Our findings demonstrate that these adapted algorithms significantly improve sensitivity to minority classes, particularly by reducing false negatives in critical defect detection. Preliminary results show notable improvements over traditional analysis techniques, highlighting the potential of these advanced methods for optimizing porosity analysis in high-pressure hydrogen vessels.By focusing on the identification of influential parameters and addressing data-related challenges, our research contributes to a deeper understanding of the effects of porosity on tank performance. This progress offers promising prospects for improving the safety and efficiency of hydrogen tanks by implementing more rigorous control strategies throughout the manufacturing process
Three-phase Active-Split source inverter with step-up/step-down DC bus voltage capabilities for traction application
No full textInternational audienceThis paper aims at proposing a new single stage DC-AC inverter with both step-up and step-down DC bus voltage capability. For a two-level inverter, the low speed operation points induce low modulation index values and poor efficiency. The proposed topology can operate in a new step-down mode to drive the motor with a DC bus voltage lower than the source for low-speed region, while still benefiting of an unaltered step-up function of the DC bus voltage. Meaning that the addition of the step-down function does not induce additional losses during step-up operation. The converter is validated both by simulation and experimentally. In step-down mode, reduced phase current ripple can be achieved, as well as reduced DClink capacitor temperature
400 V SiC MOSFET empowering three-level topologies for highly efficient applications from motor-drives to AI
No full textThis paper was presented at the EPE 2025 conference and was subsequently selected for publication in the special issue of Elsevier's PEDC journal. Therefore, only the abstract appears on the conference website.International audienceThe introduction of 400 V SiC MOSFET technology bridges the voltage range gap between 200 V medium-voltage MOSFETs and 600 V super-junction MOSFETs. This technology is characterized by low switching losses and low onstate resistance, making it suitable for 2-level topologies in 120 VAC or 300 VDC systems or 3level topologies with typical input voltages ranging from 180 VAC to 350 VAC or 400 VDC to 600 VDC. The technology concept is presented, and its efficiency and power density gains are demonstrated through measurements on test boards representing a 3-level ANPC general purpose inverter and a 3-level FC PFC for highlyefficient power supplies