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Enhancing Optimal Power Flow Feasibility: A Novel Comparative Study of Approximation Techniques
No full textInternational audienceThis experimental study investigates three approximation methods (quadratic, linear, and logarithmic) of the Optimal Power Flow problem (OPF) in comparison to traditional DC-OPF approximations using benchmark cases from the MATPOWER library. The quality and efficiency of each method is assessed using novel error metrics in respect to the AC-OPF baseline, with a focus on phase angle, voltage magnitude and generation costs. Results demonstrate promise in outperforming DC-OPF while maintaining computational efficiency, especially in the case of the quadratic approximation. Findings indicate an attainable balance between accuracy and complexity and contribute to power system modeling with implications for real-time power system management and the integration of sustainable energy
A Grid-Connected Wireless Power Transfer System with LCC-Series Compensation, Interleaved Converters, and CC/CV Charging for Wide Power Range Applications
No full textInternational audienceA 1 kW grid-connected wireless power transfer (WPT) system integrating LCC-Series (LCC-S) compensation network and interleaved converters at both input and output stages is presented in this paper. This combination achieves excellent voltage regulation and provides high efficiency over a wide range of power levels. An interleaved power factor correction (PFC) boost converter provides high input power quality meeting the IEEE 519 total harmonic distortion (THD) standards while an interleaved buck converter at the output stage minimizes the output current ripple and provides effective battery charging strategy. The constant current/constant voltage (CC/CV) charging scheme is implemented using a single proportional integral (PI) controller. The full analog design and operation reduce costs and improves reliability and noise immunity. Experimental results validate the robust performance of the system, making it suitable for practical applications
Energy-Based Model Representation for Design and Optimization of Piezoelectric Energy Harvesting Systems
No full textThe authorsacknowledge IRCICA (Research Institute onsoftware and hardware devices for informationand Advanced communication, USR CNRS3380) for providing equipment and facilities thatwere essential in advancing the project. The authors also wish to acknowledge the valuablecontributions of Frederic Giraud, Anis Kaci,Christophe Giraud-Audine, Clément Maillet,Cédric Lapeyronie and Sophie Barrau.International audienceThis paper presents a modular and adaptivemodelling and simulation tool for piezoelectricenergy harvesting (PEH) systems, applicable toportable micro-systems, such as wearabledevices, sensors, or bio-medical devices. Themain distinguishing feature of this tool is that it isdesigned to optimize the design phase and theenergy management strategies, thanks to asystemic approach. By employing EnergeticMacroscopic Representation (EMR) andinversion-based control, the tool facilitatesflexible analysis across varying levels of detail.Using this tool, a validated model is constructed,enabling the testing of power converter strategiesthat connect piezoelectric elements to loads, aswell as the evaluation of two energy harvestingstrategies for imposed displacement systems.This work demonstrates the potential of advancedmodelling techniques to enhance the design andimplementation of piezoelectric energy recoverysystem
Analysis of a one dimensional energy dissipating free boundary model with nonlinear boundary conditions. Existence of weak solutions
No full textThis work is part of a general study on the long-term safety of the geological repository of nuclear wastes. A diffusion equation with a moving free boundary in one dimension is introduced and studied. The model describes some mechanisms involved in corrosion processes at the surface of carbon steel canisters in contact with a claystone formation. The main objective of the paper is to prove the existence of weak solutions to the problem which are maximal in time. For this, a time semidiscrete minimizing movements scheme based on a Wasserstein-like distance is introduced. The existence of solutions to the scheme is proved. Then, using a priori estimates, it is shown that as the time step goes to zero these solutions converge up to extraction towards a maximal weak solution to the free boundary model
Optical Fiber-Based Nanoporous Molecularly Imprinted Polymer Sensors for the Detection of Acute Kidney Injury Biomarkers Quinolinic Acid and Tryptophan
No full textInternational audienceThe urinary quinolinic acid (QA) / L-tryptophan (T) ratio is a non-invasive prognostic biomarker for the early detection of acute kidney injury (AKI). We describe a rapid, sensitive, robust, and cost-effective detection tool in the form of a disposable optical fiber sensor for potential AKItesting, based on molecularly imprinted polymers (MIPs). AKI is a sudden and life-threatening deterioration of kidney functions. It occurs in >50% of intensive care patients and is associated to multiple organ damage. Thus, AKI is a sign of severity, requiring urgent care. AKI is often rapidly reversible at its early stage, but the current markers for AKI provide late diagnosis and they are not suitable for continuous monitoring. Therefore the implementation of point-of-care tests in clinical settings would foster its early assessment so as to trigger a rapid treatment and save numerous lives. Herein, nanoporous MIP layers endowed with a fluorescent naphthalimide reporter monomer were synthesized on the surface of optical fiber waveguides, via in situ evanescent wave photopolymerization, initiated by a visible-light sensitive photoiniferter. The photoiniferter allowed to further coat the MIP with polyethylene glycol brushes, which acted as an anti-fouling polymer layer for enhanced sensing performance of the waveguide in urine samples. The MIP-coated optical fibers exhibited specific fluorescence enhancement when binding QA and T in spiked urine. MIP binding was also selective as no recognition was observed with dipicolinic acid and D-tryptophan, which are very close structural analogues of QA and T, as well as with urea and creatinine, the major constituents of urine
Global attractor of a PDE model for the kinetics of Trichoderma fungi
No full textPartial differential equations (PDEs) are essential tools for modeling and understanding complex natural processes, particularly in biology. This research explores the growth of the fungus Trichoderma in the complex structure of soils, focusing on the production of enzymes (cellulase) during substrate degradation. The proposed reaction-diffusion model is spatialized by taking into account the diffusion of each component. We analyze the existence and uniqueness of the solutions of the obtained PDE problems, as well as their asymptotic behavior. Our results reveal the presence of a global attractor, a fundamental feature with essential implications for the long-term behavior of the system. Numerical simulations are used to illustrate the attributes of this global attractor and provide additional information on the dynamic behavior of the system
Investir dans la formation des DSIN : un pari gagnant
No full textInternational audienceFormer les directeurs et directrices des systèmes d’information et du numérique, c’est leur donner les clés pour agir dans un environnement complexe et mouvant. Depuis 2016, l’A-DSI, l’AMUE, le CSIESR et l’IH2EF unissent leurs forces pour proposer un parcours qui conjugue savoirs, pratique et réseau
Adaptive Load-Carrying Control using Quadrotors in a Tandem Configuration
No full textInternational audienceThis paper presents an adaptive control strategy for cooperative cargo transportation using quadcopters in a tan-dem configuration. By modeling the payload and the unmanned aerial vehicles (UAVs) as a unified rigid-body system, the proposed framework addresses the dynamic interactions among them, ensuring robust performance in tasks such as cargo transportation. The system uses an underactuated adaptive control approach, capable of dealing with variations in payload weight while maintaining stability and agility during flight. The proposed strategy is validated through numerical experiments, demonstrating its effectiveness in trajectory tracking tasks. The results show the system's ability to adapt the parameters of the system modeling to the observed and measured values, guaranteeing the tracking of the proposed trajectory and the robust payload handling. This work contributes to the development of cooperative aerial cargo transportation systems, with applications in transportation missions that exceed the individual capacity of each UAV
Projet NINSAR : Définition des itinéraires agroécologiques utilisant les robots
No full textThe poster provides an overview of Mohammad Naim’s doctoral work within the French national project NINSAR, which focuses on designing agroecological farming pathways supported by agricultural robots. It summarizes how the thesis examines the transition toward Agriculture 5.0, evaluates how robotic operations align with agroecological principles, studies farmers’ acceptance of robots, analyzes current robotic technologies, and explores business models for sustainable deployment.The poster presents the doctoral research of Mohammad Naim, conducted within the French national project NINSAR (New ItiNerarieS for Agroecology using cooperative Robots), and outlines how the thesis contributes to this broader research programme. The NINSAR project, as framed in the poster title and structure, is positioned as a national effort to define agroecological routes using robotics, integrating technological innovation with ecological, social, and economic sustainability goals. Within this context, the thesis investigates how autonomous agricultural systems can be designed, evaluated, and adopted without compromising core agroecological principles. The thesis analyzes the transition from Agriculture 4.0 to Agriculture 5.0 through the thirteen agroecological principles defined by the High Level Panel of Experts, assessing how emerging robotic and data-driven systems can support more sustainable production models. It evaluates three major categories of robotic field operations (data collection, soil and crop management, and navigation/communication) and links them to four principle-level agroecological indicators, finding strong contributions to soil health and synergy and weaker support for recycling. The work also conducts an empirical study of French farmers using the Technology Acceptance Model 2, identifying perceived usefulness as the central predictor of adoption, complemented by ease of use and social influence. A complementary technical study clusters 71 agricultural robots into five functional categories, illustrating the increasing specialization of robotic platforms and cost differences between electric and endothermic systems. The thesis further extends to the economic and industrial dimension of the NINSAR project by engaging manufacturers through semi-structured interviews to construct business model canvases aimed at identifying viable pathways for scaling agroecological robots. Taken together, the poster shows that Naim’s thesis forms a core component of NINSAR by integrating agronomic, technological, social, and economic analyses to support the development of robotics aligned with agroecological transition goals.Le poster présente les travaux doctoraux de Mohammad Naim, réalisés dans le cadre du projet national français NINSAR (New ItiNerarieS for Agroecology using cooperative Robots), et décrit la manière dont la thèse contribue à ce programme de recherche. Le projet NINSAR, tel qu’il apparaît dans le titre et la structure du poster, se positionne comme un effort national visant à définir des trajectoires agroécologiques appuyées par la robotique, en intégrant l’innovation technologique aux dimensions écologiques, sociales et économiques de la durabilité. Dans ce contexte, la thèse étudie comment des systèmes agricoles autonomes peuvent être conçus, évalués et adoptés sans compromettre les principes fondamentaux de l’agroécologie. La thèse analyse la transition de l’Agriculture 4.0 vers l’Agriculture 5.0 à travers les treize principes agroécologiques définis par le High Level Panel of Experts, en évaluant la capacité des systèmes robotiques et numériques émergents à soutenir des modèles de production plus durables. Elle examine trois grandes catégories d’opérations robotiques au champ (collecte de données, gestion des sols et des cultures, navigation/communication) et les relie à quatre indicateurs agroécologiques, montrant une contribution forte à la santé des sols et à la synergie, mais plus limitée au recyclage. Le travail inclut également une étude empirique auprès d’agriculteurs français utilisant le modèle TAM2 (Technology Acceptance Model 2), révélant que l’utilité perçue constitue le principal déterminant de l’adoption, complétée par la facilité d’usage et l’influence sociale. Une étude technique complémentaire regroupe 71 robots agricoles en cinq catégories fonctionnelles, illustrant la spécialisation croissante des plateformes robotiques et les différences de coût entre les systèmes électriques et endothermiques. La thèse s’étend enfin à la dimension économique et industrielle du projet NINSAR en impliquant des fabricants à travers des entretiens semi-directifs pour construire des canevas de modèles d’affaires (Business Model Canvas) permettant d’identifier des voies viables pour le déploiement de robots agroécologiques. Dans l’ensemble, le poster montre que la thèse de Naim constitue un élément central de NINSAR en intégrant des analyses agronomiques, technologiques, sociales et économiques pour soutenir le développement d’une robotique alignée sur les objectifs de transition agroécologique
Long Range Cortical Interactions During Comparison of Sensory and Cognitive Information
No full textInternational audienceAdapting our behavior to our environment depending on contextual demands involves large, distributed networks of cortical and subcortical areas. Prefrontal (PFC) and lateral intraparietal area (LIP) process both sensory and cognitive factors in very similar manner. However, their respective contributions to visual processing and cognitive control remain largely unclear. In this study, macaque monkeys performed a modified delay-match to sample task while we simultaneously recorded neuronal activity from V4, LIP and PFC. We show differential PFC/LIP dynamics: PFC exhibits successive encoding of different cognitive processes, while LIP shows more stable representations that integrate both sensory and cognitive signals.</div