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Challenges of operating multiple distributed generators with different primary control strategies in microgrids: Interactions and performance assessment
No full textInternational audienceThis study investigates the effectiveness of hybrid power-sharing control strategies in microgrid systems. It integrates various droop controllers, including conventional droop, universal droop, dVOC, and VSG. The contribution of each controller is evaluated in terms of system stability, efficiency, and adaptability. These assessments consider how different test conditions influence overall system performance. The performance analysis focuses on power sharing during both transient and steady-state conditions. It accounts for DERs connected through complex transmission line impedances and subjected to variable local loads. The study concludes with extensive real-time simulations using the Typhoon HIL 604 platform. These scenarios test different operating conditions to identify the most stable microgrid configuration
An iterative CP approach for handling min/max worload constraints in preemptive JSP
No full textInternational audienceAn iterative CP approach for handling min/max worload constraints in preemptive JS
Runtime Monitoring for Safety-Critical Vision-based Runway Detection
No full textInternational audienc
Polyconvex double well functions
No full textThis version fixes a flaw in the main theorem of the previous version.International audienceWe investigate polyconvexity of the double well function for given matrices . Such functions are fundamental in the modeling of phase transitions in materials, but their non-convex nature presents challenges for the analysis of variational problems. Polyconvexity of is related to the singular values of the matrix difference . We prove that is polyconvex if and only if the square of the largest singular value does not exceed the sum of the squares of the other singular values. This condition allows the function to be decomposed into the sum of a strictly convex part and a null Lagrangean. As a direct application of this result, we prove an existence and uniqueness theorem for the corresponding Dirichlet minimization problem of the integral functional
A path planning heuristic for automated guided vehicles in container terminals
No full textInternational audienceThe use of Automated Guided Vehicles for container transportation within container termi- nals has emerged as a promising approach to enhance their efficiency and competitiveness over the last two decades. This development has created a need to optimize the utilization of these resources, partic- ularly through efficient path planning within their operating environment. In this work, we propose a Integer Linear Programming-based heuristic to address the problem of collision-free path planning for Automated Guided Vehicles in automated container terminals, where multiple transportation missions need to be performed by each vehicle. The method is evaluated and tested through extensive numeri- cal experiments. Conclusions are drawn regarding its efficiency, and directions for future research are suggested
CLOE: Fonction de perte basée sur Christoffel pour Autoencoder appliquée à de la détection d'anomalies
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Extended-Precision FMA under Parameterized Double-Word Overlap: Tight Error Bounds and Examples
No full textWe study fast fused multiply--add (FMA) kernels for approximating in extended precision using double-word (DW) representations in floating-point (FP) arithmetic. We focus on how worst-case guarantees depend on the overlap between the high and low parts, modeled by parameterized conditions of the form (and two- and three-parameter variants for multiple DW inputs). We consider the dominance regime and its DW analogues (e.g., and ), which occur in fast paths for elementary-function evaluation and in cancellation-free constructions. Within this regime, we tighten and extend error analyses for several FMA-based schemes used in recent extended-precision implementations. We analyze FP/DW and DW/DW variants, derive explicit worst-case constants for both the returned low part and the overall relative error, and provide matching worst-case examples. The resulting bounds give a unified and quantitative view of how DW-overlap assumptions affect the accuracy of fast extended-precision FMA building blocks
Gaussian-like fixed point and variational properties of integral discriminants
No full textInternational audienceWe consider partition functions Z(g) = exp (-g(x))dx where g is a nonnegative polynomial action (a degree-2n form) vanishing only at the origin. Such integrals, known as integral discriminants, appear in statistical mechanics, quantum field theory, and the theory of exponential families. We show that the associated Boltzmann measure dµ = exp(-g(x))dx satisfies a fixed-point property identity relating in a simple manner its degree-2n moments to the coefficients of g. This generalizes familiar identities for the exponential distribution (degree-1) on the positive orthant and the Gaussian measure (degree-2). We further show that g is characterized by three variational principles, including a maximum-entropy principle under scaled moments constraints, extending the Gaussian extremality principle to arbitrary even-degree homogeneous actions. Exploiting these identities in a truncatedmoment numerical scheme (known as the Moment-SOS hierarchy), strengthens the standard semidefinite relaxations, and results in a much faster convergence, thus allowing more efficient approximations of the partition function Z(g) as well as moments of µ
940-nm VCSELs grown by molecular beam epitaxy on Ge(001)
No full textInternational audienceVertical-cavity surface-emitting laser (VCSEL) structures emitting near 940 nm were grown by solid source molecular beam epitaxy (MBE) on Ge(001) substrates. The VCSEL MBE-growth was realized upon a virtual substrate composed of GaAs on Ge grown by melatorganic vapour phase epitaxy (MOVPE). In situ monitoring during MBE growth employed multispectral reflectometry and magnification-inferred curvature imaging for real-time growth analysis. Curvature measurements revealed progressive compressive stress, while optical reflectivity data confirmed uniform layer growth and accurate stopband formation. Fabricated devices with mesa diameters of 35-40 µm, corresponding to oxide apertures of approximately 11-16 µm, exhibited room-temperature lasing under continuous-wave bias with threshold currents below 3 mA. To the best of our knowledge, this is the first demonstration of monolithically integrated 940 nm VCSELs grown on Ge substrates by MBE. These results confirm the viability of MBE-grown VCSELs on Ge with in situ process control for scalable optoelectronic integration
Programming the Optoelectronic Properties of Atomically Precise Gold Nanoclusters Using the Conformational Landscape of Intrinsically Disordered Proteins
No full textInternational audienceThe rational design of hybrid nanomaterials with precisely controlled properties remains a central challenge in materials science. While atomically precise gold nanoclusters (Au‐NCs) offer molecule‐like control over a metallic core, tuning their optoelectronic behavior via surface engineering is often empirically driven. Here, we establish a design principle by demonstrating that the conformational landscape of intrinsically disordered proteins (IDP) can be used as a programmable scaffold to rationally modulate the photophysical properties of a covalently bound Au‐NC. We synthesized a series of bioconjugates between Au 25 nanoclusters and bioengineered IDPs containing a variable number of cysteine anchoring points. A combination of mass spectrometry, small‐angle X‐ray scattering, and modeling on the conjugates indicates that increasing the number of covalent anchors systematically restricts the conformational ensemble, inducing a progressively more compact protein shell around nanoclusters. This structural rigidification at the interface directly translates into a 15‐fold enhancement of the Au‐NC near‐infrared photoluminescence and a six‐fold increase in its average lifetime. Our findings demonstrate that the conformational plasticity of IDPs and the capacity to engineer them can be harnessed as a molecular tuning knob, moving to a new regime of programmable soft‐matter control over the properties of quantum‐confined nanomaterials for tailored biotechnological applications