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Author Correction: Reconfigurable biconcave lens antenna based on plasma technology
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Les Cifre en tiers-lieux: interstices singuliers entre recherche et action
No full textNational audienceSelon le rapport France Tiers-Lieux (2021), les tiers-lieux font émerger des pratiques de recherche et d’innovation en dehors des cadres habituels de la science (laboratoires de recherche, grandes entreprises). Ces espaces d’expérimentation invitent à penser les façons de faire recherche autrement par rapport à larecherche académique classique. Toutefois, la littérature scientifique comporte peu de travaux portant spécifiquement sur les interactions qu’entretiennent les tiers-lieux et la recherche.Après avoir situé les approches de recherche en tiers-lieux, nous proposons d’en saisir les manifestations et les enjeux, à travers quatre récits d’expérience en contrat doctoral Cifre, présentant des situations de recherche singulières à la rencontre entre savoirs d’action et connaissances scientifiques
Towards a Unifying Reference Model for Digital Twins of Cyber-Physical Systems
No full textInternational audienceDigital twins are sophisticated software systems for the representation, monitoring, and control of cyber-physical systems, including automotive, avionics, smart manufacturing, and many more. Existing definitions and reference models of digital twins are overly abstract, impeding their comprehensive understanding and implementation guidance. Consequently, a significant gap emerges between abstract concepts and their industrial implementations. We analyze popular reference models for digital twins and combine these into a significantly detailed unifying reference model for digital twins that reduces the concept-implementation gap to facilitate their engineering in industrial practice. This enhances the understanding of the concepts of digital twins and their relationships and guides developers to implement digital twins effectively
Unveiling the Hidden Feast: A Model to Translate Molecular Detection Into Predation Rate—Application Example on Biological Control by Generalist Predators in Agricultural Fields
No full textInternational audienceFew processes are as decisive as predation in shaping the structure and dynamics of ecological communities. For most predator species, however, the number of prey items killed by a predator in a day (predation rate) remains impossible to assess because direct observations are scarce or impossible to acquire. For such species, molecular gut content analyses are routinely used to test for the presence of a prey in the predator's gut. Specifically, our model uses a novel mechanistic representation of predation and digestion to integrate field data on prey detection and laboratory data on prey molecular signal decay in the predator's gut. Model fit provides an estimate of the slope and intercept of the digestion curve (molecular signal decay) and an estimate of the predation rate. In a case study targeting 25 carabid beetle species and 5 types of prey in agricultural fields (winter wheat), we use our model to estimate predation rates for each predator–prey pair. Based on predation rate estimates, we introduce a new biocontrol indicator at community scale and explore its potential for advanced agroecological research. We discuss the performance of our model on the basis of the scant information available in the literature and detail its conditions of application to highlight its advantages over existing predation models
Dynamical Systems. Paths of twelve mathematicians and physicists to chaos and its applications
No full textInternational audienceThis book offers a captivating exploration of the intersection between mathematics, chaos theory, and dynamical systems through the personal journeys of twelve renowned mathematicians and physicists from China, Europe, Russia, and the USA.The first section of this book provides an intimate look into the formative experiences and early steps of these scientists. In these life stories, the names of other famous mathematicians arise, crisscrossing all the stories in unexpected ways. The second part of this book explores the practical applications of chaotic attractors in various fields. These include chaos-based encryption in cryptography, sensor and actuator placement in Chua circuits for control systems, and chaotic dynamics in remote sensing for crop modeling. It also highlights the role of chaos theory in the development of memristors following Leon Chua’s 1971 discovery, leading to advances in nonlinear dynamics, hyperchaos, and memristor-based systems. The chapters further examine how chaos theory addresses modern challenges suchas modeling COVID-19 spread using SEIR models and optimizing mobile network design, demonstrating the wide-reaching impact of chaotic systems in real-world applications.This book will be of great value to students and researchers in mathematics, physics, engineering, and related disciplines seeking to deepen their understanding of chaotic dynamical systems and their applications
Environnement d'Exécution Matériel/Logiciel pour la protection GPSA de Coeurs Embarqués RISC-V
No full textInternational audienceState-of-the-art hardware countermeasures against fault attacks are based, among others, on control-flow and code integrity checking. Generalized Path Signature Analysis and Continuous Signature Monitoring can assert these integrity properties. However, supporting such mechanisms requires a dedicated compiler flow and does not support indirect jumps. This work proposes a technique based on a hardware/software runtime to generate those signatures while executing unmodified off-the-shelf RISC-V binaries. To the best of our knowledge, this is the first solution for providing this level of protection against fault injection on unmodified binaries. The proposed approach has been implemented on a pipelined processor, and experimental results show an average slowdown of ×3.35 and an area overhead of at least ×1.86 compared to unprotected implementations
Multifunctional Dual-Band Metasurface-Based Transmit- and Reflect-Arrays at Sub-THz
No full textInternational audienceIn this paper, we present the design of a dual-band multifunctional metasurface-based (MMS) transmit- and reflect-array (TRA) antennas for wave manipulation at sub-terahertz (sub-THz). The proposed design allows independent beam control in both transmission and reflection hemispheres. The MMS exploits 1-bit phase control of the incident wave over a wide bandwidth while maintaining remarkably low insertion and reflection losses, using only three metallic layers. Passive dual-band TRA antennas, consisting of 30×30 unit-cells (UCs), are demonstrated based on the metasurface phase modulation capability. These features make the proposed MMS a highly promising solution for next-generation sub-THz applications, offering independent full space beamforming and steering coverage
Dispositifs à base de Phosphure de Gallium pour l'optique non-linéaire intégrée
No full textInternational audienceNous comparons ici différentes plateformes de Phosphure de Gallium pour la fabrication de nano-guides d'onde pour des applications de photonique non-linéaire intégrée. La comparaison des plateformes se fait particulièrement sur l'analyse des pertes dans l'infrarouge. Nous démontrons l'état de l'art pour la plateforme GaP sur GaAs
Characterization and modeling of polyoxometalate-based ionic liquids. Force field refinement and insights into their dynamical behavior
No full textInternational audienceIonic liquids (ILs) are salts with melting points below 100 °C, being a more sustainable alternative to organic solvents because of their negligible vapor pressure and high thermal stability. The recently developed branch of polyoxometalate-based ILs (POM-ILs) incorporates the unique properties (redox, catalytic) of POMs to the advantages of ILs, opening the door to further advancements and applications in the field. In the present work we have synthesized and characterized new POM-ILs. Motivated by this progress and building upon current knowledge on simulations of classical ILs, we also propose a computational setup to describe the dynamic behavior of bulk POM-ILs through atomistic molecular dynamics simulations. The cationic part is an organic PR4+ unit, and POMs are well-known systems such as Lindqvist, Keggin and Wells-Dawson, among others. Part of the work presents variations made to the (reference) AMBER force field atomic parameters σ and ε, and their justification. We observe that changes applied remarkably affect the molecular mobilities (diffusivities or viscosities) of the system. Our analysis establishes that one set of the tested parameters reproduces the relative experimental viscosities for the family of compounds analyzed. Taking this setup, we further describe computationally the local and bulk dynamical properties, detailing the anion-cation interactions. One remarkable fact is that the experimental diffusivities are reproduced with very little microscopic molecular motion, that is, the mobility of the constituent parts is very limited, mostly restricted to a local position