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Towards optimal reconfigurable constant multipliers
No full textInternational audienceThis paper introduces a novel algorithm for generating run-time reconfigurable single constant multipliers (RSCMs) which are optimal within their model in terms of hardware cost. Optimality is ensured by an exhaustive exploration of the design space mixing constraint programming, depth-first search, and branch-and-prune techniques. The cost model of previous works is also refined. Compared to the state of the art, this approach enables much larger constant sets, and also significantly improves the performance of the resulting architectures. Applications to neural network inference and small floating point multiplication units are evaluated
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
Intraluminal pressure triggers a rapid and persistent reinforcement of endothelial barriers
No full textInternational audienceIn response to mechanical cues, endothelial cells elicit highly sensitive cellular response pathways that contribute to the regulation of the physiology and disorders of the vascular system. However, it remains relatively unexplored how endothelial tissues process and integrate the intraluminal pressure, and in turn regulate the permeation flow across the vessel wall. Leveraging a tissue engineering approach to create microvessels (MVs), we measured real-time permeation flow induced by intraluminal pressures ranging from 0.1 to 2.0 kPa. Our findings reveal that mechanically stimulated MVs strengthen their barrier function within seconds of exposure to pressures below 1 kPa, with this enhanced barrier function persisting for 30 minutes. We demonstrate that this barrier reinforcement is linked to the closure of paracellular gaps. Additionally, we observe that it is associated with, and depends on, actin cytoskeleton reorganization, including the accumulation of stress fibers near intercellular junctions and the broadening of adherence junction protein localization. These findings provide insights into the ability of endothelial tissues to regulate interstitial fluid flow in response to sudden increases in blood pressure
Lithography processes
No full textMasterThis course introduces the fundamentals of photolithography, a key technique in micro-nanofabrication used to transfer patterns onto substrates. It provides a detailed explanation of the process steps: substrate preparation, photoresist coating and baking, UV exposure, development, and etching. The principles of operation and the parameters affecting resolution and pattern quality are discussed, including photoresist selection, film thickness, and exposure conditions. The course briefly mentions other techniques such as electron-beam and laser lithography to place photolithography in the broader context of available methods. It emphasizes the importance of mastering these processes for the fabrication of microelectronic devices and MEMS. Finally, a comparison of the constraints and applications of photolithography is presented, along with concrete examples from research conducted at LAAS-CNRS
Conventional micro and nanofabrication techniques and processes
No full textInternational audienceThis presentation will show how established micro- and nanofabrication techniques contribute to progress in electronics, sensing technologies, and medical applications. After introducing the cleanroom environment, essential for controlling contamination and ensuring high-precision fabrication, it will highlight versatile processes for creating thin films, patterning materials, and defining structures at micro- and nanoscales.The talk will showcase advanced lithography and etching techniques that enable the miniaturization of components, unlocking new possibilities for high-performance devices. Examples of ongoing projects, such as the development of sensitive gas sensors for environmental and health applications, will illustrate the transition from fabrication processes to real-world solutions.Finally, an overview of current research will demonstrate how micro- and nanotechnologies are evolving to meet the demands of future applications, particularly in life sciences and cancer diagnostics, paving the way for smarter, more efficient, and more integrated devices
Euronanolab Lithography Expert Group
No full textNational audienceThis presentation by the lithography expert group of the EuroNanoLab network details the actions carried out in 2024-2025, including the organization of online workshops on laser lithography, e-beam and mask fabrication, as well as a face-to-face meeting on ion lithography. It offers a comparison of resist processes with common masks and patterns, to characterize resolution, profile and ease of use. Staff exchanges are facilitated between platforms thanks to Erasmus+ and NFFA. A collaborative database on resits, tools and processes is under construction. The initiative encourages knowledge sharing and the collective resolution of technical problems. Finally, actions that can be transposed to Renatech can be proposed, such as cross-training and inter-platform comparison projects.Cette présentation du groupe d’experts lithographie du réseau EuroNanoLab détaille les actions menées en 2024-2025, notamment sur l'organisation de workshops en ligne sur la lithographie laser, e-beam et la fabrication de masques, ainsi qu’une réunion présentielle sur la lithographie ionique. Elle propose une comparaison des procédés de résines avec des masques et motifs communs, pour caractériser la résolution, le profil et la facilité d’utilisation. Des échanges de personnels sont facilités entre plateformes grâce à Erasmus+ et NFFA. Une base de données collaborative sur les résines, outils et procédés est en construction. L’initiative encourage le partage des connaissances et la résolution collective de problèmes techniques. Enfin, des actions transposables à Renatech peuvent être proposées, comme des formations croisées et des projets de comparaison inter-plateformes
Multi-block local outlier factor anomaly detection of complex industrial systems
No full textInternational audienceAnomaly detection is critical in industrial systems for ensuring equipment reliability and improving product quality, especially with the increasing complexity of electronic board production. However, traditional anomaly detection approaches often fail when dealing with high-dimensional data and limited system knowledge. To address this gap, this article aims to develop an effective unsupervised method for anomaly detection suitable for large-scale industrial contexts with minimal prior knowledge. The proposed Multi-block Local Outlier Factor (MLOF) method combines a variable decomposition technique based on Mutual Information and spectral clustering with a local anomaly detection algorithm using the Local Outlier Factor. The method was validated on the Tennessee Eastman Process and real-world industrial cases from Surface Mount Technology production lines, notably by comparing its results with 5 other methods in the literature. Results demonstrate a 15% improvement in anomaly detection performance compared to classical LOF on benchmark data and effective application in detecting anomalies in real production scenarios. The MLOF method represents a significant step forward in anomaly detection for complex systems, offering robust, scalable, and accurate solutions even in data-intensive and knowledge-scarce environments
Collage d'une cellule photovoltaïque GaAs sur substrat de cuivre par thermocompression pour l'hybridation photovoltaïque-thermoélectrique
No full textInternational audiencePhotovoltaic thermoelectric hybridization is a pathway to produce electric power using the heat generated in a photovoltaic cell as a heat source for a Seebeck thermoelectric generator. However, previous studies showed the need to reduce the thermal resistance between the photovoltaic cell and the thermoelectric generator to achieve high power conversion efficiency. To minimize this thermal resistance, we propose in this study a method for transferring the cell onto a custom copper substrate and removing the growth substrate from the epitaxial layer by Au-Au interdiffusion bonding and full substrate etching. Using various characterization methods, we identify the challenges in each process step for upscaling this process on a larger surface. The first cell transfer attempt achieved a mirror-like surface roughness on the epitaxial layer. Analysis of the defects caused by the bonding and the etching step allow us to identify optimizations to apply the process to the centimeter-scale area
Modular Simulator for DAE-Based Systems Using DEVS Formalism
No full textInternational audienceModeling and Simulation of dynamic structure systems present some difficulties, particularly those represented by Differential-Algebraic Equations (DAEs), as structural changes often require modifying equations.To address this, we propose a methodology to build simulators based on Theory of Modeling and Simulation, laying as a foundation for rigorously handling such systems. Our proposal consists of a modular, domainindependent simulator where system's behavior can be represented by DAEs. Systems are represented as graphs, dynamically updated at each step based on predefined scenarios. The simulator automatically generates and processes equations using transformation rules applied to input graphs. To demonstrate the feasibility of our proposal, we apply it to the domain of power systems, particularly the Load Flow Analysis process
