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L'insuffisance professionnelle d'un agent contractuel justifiant son licenciement doit être appréciée sérieusement et pendant une période raisonnable
No full textInternational audienceNote sous CAA Bordeaux, 4 février 2025, no 23BX00203, Commune de Bella
Reachability for multiagent control systems via Lyapunov functions
No full textInternational audienceThis paper concerns the problem of reachability of a given state for a multiagent control system in . In such a system, at every time each agent can choose his/her velocity which depends both on his/her position and on the position of the whole crowd of agents (modeled by a probability measure on ). The main contribution of the paper is to study the above reachability problem with a given rate of attainability through a Lyapunov method adapted to the Wasserstein space of probability measures. As a byproduct we obtain a new comparison result for viscosity solutions of Hamilton Jacobi equations in the Wasserstein space
Variability of damping properties for viscoelastic composite plates of flax fibers
No full textInternational audienceThis paper aims at taking into account uncertainties of material and physical properties of flax/epoxy composite structures and evaluating their impacts onto the variability of free vibration responses. The natural character of the fiber indeed induces a quite important variability to properties of composite structures, leading to a noticeable variability of responses, possibly hindering its use. The variability of elastic moduli and thicknesses for flax/epoxy multi-layer structures is here modeled to investigate their influence on the variability of damping characteristics such as damping frequency and damping. The quantification of input uncertainties comes from an experimental campaign. The non-linear vibration problem of composite structures is solved by a High Order Newton method. The Monte Carlo Simulation method associated to a Modal Stability Procedure is here proposed using homotopy perturbation technique to deal with the frequency-dependent structure. Two viscoelastic constitutive laws are considered, the generalized Maxwell model and the Fractional derivative Zener model. The test case is a cantilever flax/epoxy rectangular plate and three stacking sequences are considered. The propagation of uncertainties is performed in order to determine the output variability level and the most influent parameters regarding damping characteristics of this structure
Polynomial Bridgeland Stability Conditions on the Category of Coherent Sheaves
No full textIn this short note, we provide a broad class of examples of stability conditions on the category of coherent sheaves which generalise Gieseker stability. We refer to them as "adapted to coherent sheaves" and they admit Harder--Narasimhan and Jordan--Hölder filtrations. We also study the particular case of Bayer's polynomial Bridgeland stability conditions, and their relation to the gauge theoretical counterpart introduced by Dervan--McCarthy--Sektnan
Aligning individual brains with Fused Unbalanced Gromov-Wasserstein
No full textIndividual brains vary in both anatomy and functional organization, even within a given species. Inter-individual variability is a major impediment when trying to draw generalizable conclusions from neuroimaging data collected on groups of subjects. Current co-registration procedures rely on limited data, and thus lead to very coarse inter-subject alignments. In this work, we present a novel method for inter-subject alignment based on Optimal Transport, denoted as Fused Unbalanced Gromov Wasserstein (FUGW). The method aligns cortical surfaces based on the similarity of their functional signatures in response to a variety of stimulation settings, while penalizing large deformations of individual topographic organization. We demonstrate that FUGW is well-suited for whole-brain landmark-free alignment. The unbalanced feature allows to deal with the fact that functional areas vary in size across subjects. Our results show that FUGW alignment significantly increases between-subject correlation of activity for independent functional data, and leads to more precise mapping at the group level
Sustainable 4D Printed Meta Biocomposite Materials for Programmable Structural Shape Changing
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Un prince oublié ou la figure de la légitimité dynastique: Louis le Grand Dauphin et l'Espagne de Philippe V
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Model-Free Speed Control for Pumping Kite Generator Systems Based on Nonlinear Hyperbolic Tangent Tracking Differentiator
No full textInternational audienceThis paper investigates the emerging field of grid-connected wind-powered pumping kite generator system (PKGS), focusing on the challenges associated with the generator/motor speed control. Conventional use of proportional–integral (PI) controllers faces difficulties in meeting requirements for dynamic response, tracking performance, stability, and disturbance rejection encountered in this technology, notably the periodical variation in the rotational speed reference in maximum power point tracking in generation phases and the dynamic response for the step reference in transient ones. To overcome these limitations, a model-free controller (MFC) approach is introduced, also known as intelligent PID controllers. Unlike traditional methods, MFC does not rely on a control model of the system and adapts to uncertainties and disturbances through online estimation based on the system’s input–output behavior. To further improve the control performances, a tracking differentiator based on a nonlinear hyperbolic tangent function is integrated in the MFC. The effectiveness of the proposed strategy is proved through simulations in MATLAB/Simulink. The results highlight the superior performances of the proposed MFC approach in terms of speed control accuracy, response time, and robustness
