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Le juge et les garanties de passif : quelques rappels utiles sur le traitement judiciaire des garanties
No full textInternational audienceNote sous Com., 28 mai 2025, no 24-13.182 (no 291 F-D
Combined Deep KKL and NMPC for Modeling Muscle Co-contraction Under Measurement Delays
No full textThis paper addresses the modeling of robust control through muscle co-contraction, a fundamental physiological strategy that modulates mechanical impedance and stabilizes limb dynamics. Here, the neuromusculoskeletal system is modeled as nonlinear dynamics actuated by antagonist muscles, subject to uncertainties and significant output measurement delays. To account for muscle co-contraction for robust control in simulation, we propose a closed-loop control framework based on Nonlinear Model Predictive Control (NMPC) and test it for a forearm stabilization task (inverted pendulum). While NMPC is well-suited for handling system constraints and mimicking physiological objectives, its real-time implementation requires the estimation of the instantaneous initial state, which is unavailable due to the delays. To address this, we introduce a delay-compensating Kazantzis-Kravaris-Luenberger (KKL) observer. This observer embeds the nonlinear dynamics into a stable linear latent space, enabling explicit delay compensation through a chain of predictors. To overcome the analytical complexity of the required transformation maps, we employ a Deep Learning approach to approximate the observer dynamics. Finally, the performance and robustness of the Deep KKL-NMPC scheme are validated through extensive simulations of posture stabilization and dynamic tracking tasks under stochastic environmental disturbances
Physics-Informed Neural Estimation of State and Unknown Input inAutonomic Cardiac Dynamics with Left-Invertibility Constraints
No full textInternational audienceUnderstanding brain–heart interaction (BHI) requires models that capture how the central nervous system and the cardiovascular system co-regulate each other under internal and external stressors to preserve homeostasis and give rise to macroscopic physiological states such as sleep, arousal, or vigilance. At the core of this loop are interoceptive variables, defined as latent autonomic control signals that encode the body’s internal state and drive cardiac adjustments; however, these variables are not directly measurable. Recovering these hidden drives from peripheral cardiac signals requires taking into account nonlinear dynamics and physiological confounds, as well as limited measurement data. This work proposes a physics-informed neural estimator for simultaneous state estimation and reconstruction of unknown control inputs in a nonlinear, coupled model of autonomic cardiac regulation. The estimator enforces model-based constraints along with data-driven regularization, and embeds structural identifiability conditions derived from the system itself, yielding guarantees without prescribing a dynamical prior for the unknown input. Validation of stressevokedcardiac recordings shows the accurate recovery of heart rate, along with estimates of state (being blood pressure) and the unknown control input (being the blood-pressure setpoint); hence, enabling physiology-consistent, left-invertible inferenceof interoceptive autonomic dynamics
Trésors cachés, louis exhibé : la monnaie comme objet théâtral chez Plaute et Molière
No full textInternational audienceLa plume des dramaturges fait des deux trésors monétaires cachés par un avare des « objets théâtraux » (Martial Poirson), dans L’Aululaire de Plaute et L’Avare de Molière, en opposition avec le louis d’or exhibé par Dom Juan face au pauvre. L’analyse porte sur les fonctions multiples de ces monnaies : objet dramaturgique comme moteur de l’intrigue, transactionnel dans l’économie domestique, scénique selon sa place dans la scénographie, symbolique en tant qu’objectif ultime ou marque de pouvoi
"Grant fu la jeste, bien en doit on parler". Mélanges en l'honneur de Bernard Ribémont
No full textInternational audienceProfesseur de littérature médiévale à l’université d’Orléans de 1991 à 2018, après une première carrière de mathématicien et d’ingénieur, Bernard Ribémont a exploré ce champ sous de multiples angles, notamment le droit et l’encyclopédisme, tout en fondant des structures de recherche, des collections et des revues majeures. Esprit curieux et audacieux, il s’est distingué par son œuvre foisonnante, son engagement interdisciplinaire et son énergie hors du commun. Les trente-sept contributions réunies dans le présent volume rendent hommage à son travail autour de quatre axes qui lui tiennent à cœur : les sciences et les savoirs, les rapports entre littérature, droit et histoire, l’œuvre de Christine de Pizan et la chanson de geste
Congruences for hook lengths of partitions
No full text14 pages, all comments are welcome ! arXiv admin note: text overlap with arXiv:2107.06793International audienceRecently, Amdeberhan et al. proved congruences for the number of hooks of fixed even length among the set of self-conjugate partitions of an integer , therefore answering positively a conjecture raised by Ballantine et al.. In this paper, we show how these congruences can be immediately derived and generalized from an addition theorem for self-conjugate partitions proved by the second author. We also recall how the addition theorem proved before by Han and Ji can be used to derive similar congruences for the whole set of partitions, which are originally due to Bessenrodt, and Bacher and Manivel. Finally, we extend such congruences to the set of -asymmetric partitions defined by Ayyer and Kumari, by proving an addition-multiplication theorem for these partitions. Among other things, this contains as special cases the congruences for the number of hook lengths for the self-conjugate and the so-called doubled distinct partitions
Sustainable sandwich composites with 3D-printed perforated panels and natural fibers for noise control
No full textInternational audienceThis study presents the design, fabrication, and acoustic evaluation of eco-friendly sandwich composites integrating 3D-printed micro-perforated panels (MPPs) with natural fiber core layers. MPPs, produced from Polylactic Acid (PLA) and Thermoplastic Polyurethane (TPU) via fused deposition modeling, were manufactured with varying hole diameters (1.0 mm, 1.3 mm), center-to-center spacings (3.0 mm, 5.0 mm), and thicknesses (0.5 mm, 1.5 mm). Hemp and waste wool fibers were used as core layers. The effects of structural and material parameters on the sound absorption coefficient (SAC), noise reduction coefficient (NRC), NRC-modified values, and sound absorption average (SAA) were evaluated through a systematic experimental investigation. The findings showed that sandwich composites with a waste wool core and TPU panels exhibited superior acoustic performance, with optimal MPP designs identified as 1.3 mm diameter and 1.5 mm thickness, combined with 3.0 mm spacing for wideband absorption and 5.0 mm spacing for targeted low-frequency absorption. Statistical analysis confirmed that hole diameter, hole spacing, panel thickness and material selection had a significant impact on acoustic performance. These results were theoretically validated through an theoretical modeling approach. The findings highlighted the potential of using 3D printing and natural fibers to create sustainable sandwich structures with optimal acoustic performance, offering a practical design framework for tailoring panel configurations to target frequency ranges and enabling eco-friendly, high-performance noise control solutions in architectural, transportation, and industrial applications
Revisiting FRB 20121102A: milliarcsecond localisation and a decreasing dispersion measure
No full textInternational audienceFRB 20121102A is the original repeating fast radio burst (FRB) source and also the first to be localised to milliarcsecond precision using very-long-baseline interferometry (VLBI). It has been active for over 13 years and resides in an extreme magneto-ionic environment in a dwarf host galaxy at a distance of ~1 Gpc. In this work, we use the European VLBI Network (EVN) to (re-)localise FRB 20121102A and its associated persistent radio source (PRS). We confirm that the two are co-located -- improving on previous results by a factor of ~4 and constraining the FRB and PRS co-location to ~12 pc transverse offset. Over a decade, the PRS luminosity on milliarcsecond scales remains consistent with measurements on larger angular scales, showing that the PRS is still compact. We also present the detection of 18 bursts with the Nancay Radio Telescope (NRT) as part of our ÉCLAT monitoring program. These bursts, together with previously published results, show that the observed dispersion measure (DM) of FRB 20121102A has dropped by ~25 pc/cc in the past five years, highlighting a fractional decrease in the local DM contribution of >15%. We discuss potential physical scenarios and highlight possible future observations that will help reveal the nature of FRB 20121102A, which is one of only a few known FRBs with a luminous PRS
L’empowerment en santé : la révolution douce des associations de patients
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Rapid cell turnover to model adipocyte size distribution
No full textInternational audienceWhite adipose tissue, composed of adipocyte cells, primarily stores energy as lipid droplets. The size of adipocytes varies significantly within the tissue according to the amount of stored lipids. A striking observation is that the adipocyte size distribution is bimodal, and thus, this tissue is lacking a characteristic size.We propose a novel dynamical model, based on a partial differential equation, to represent the adipocyte size distribution. The model assumes continuous adipocyte growth, with a velocity dependent on cell radius and extracellular lipid availability, together with constant rates of cell recruitment and death.We prove the existence and local stability of a unique stationary solution for a broad range of growth velocity functions. Choosing a parsimonious formulation, we show that only three parameters are enough to describe adipocyte size distributions measurements in rats. These parameters are robustly estimated through approximate Bayesian computation, and the model demonstrates excellent agreement with experimental data. This mechanistic, three-parameter framework offers a new and interpretable approach to characterizing adipocyte size distributions