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Continuous Frequency Agile Horizontally Polarized Miniature Low-UHF Loop Antenna for IoT Applications
No full textInternational audienceA low profile, miniature, horizontally polarized loop antenna is proposed to work in the 400-450 MHz UHF band. The wide band coverage is obtained through continuous frequency reconfiguration through varicap loaded ends of the loop. A study on miniaturization effects on performance as well as on matching loads is presented. After the optimization the proposed antennaconfirms to work as a magnetic dipole with a total efficiency greater than 90% between 400 MHz and 440 MHz
Le Détroit touristique d’hier à aujourd’hui : automobile, ruine et MICE (Michigan Central Station), salon (Detroit Auto Show) au service d’une renaissance ? La question du tourisme événementiel régénératif - My Drive, My Show, My Business, My City, My Detroit, MOTOR CITY
No full text« Ce travail a bénéficié d’une aide du gouvernement français, gérée parl’Agence Nationale de la Recherche au titre du Pan d’investissement France2030, dans le cadre de l’Initiative d’Excellence d’Université Côte d’Azur portantla référence ANR-15-IDEX-01.»International audienceLong regarded as a symbol of American industrial decline, Detroit is now experiencing a touristic revival, with its attractiveness sustained—despite the city’s bankruptcy—by a persistent branding strategy. The city's image is carefully staged and narrated by Visit Detroit, a communications office that projects a dual discourse combining leisure-cultural appeal and business-tourism potential. Once the global capital of the automobile industry, Detroit endured profound economic hardship and deindustrialisation, leaving behind an urban landscape scarred by shrinkage and architectural decay. In parallel with the rise of the so-called ruin porn phenomenon—which aestheticises abandoned buildings and has captured the imagination of photographers and urban explorers—debates have emerged surrounding the ethical tensions between heritage in transition and voyeuristic tourism. Amid these discourses, a new urban and marketing strategy has taken shape, centred on hosting major events of the MICE type (Meetings, Incentives, Conferences, and Exhibitions). While some of these events follow conventional formats, there is a growing will for them to operate as regenerative initiatives that benefit Detroit’s entire community—its central neighbourhoods and impoverished outskirts alike—through the involvement of conscious, locally engaged visitors attuned to the city’s renewed social contract or “New Deal.” In this context, the very scars of the past have become assets in a broader strategy of touristic reinvention. New urban amenities are emerging or being repurposed through business tourism and convention activity—tools which, since the 19th century, have contributed to building a dynamic, forward-looking image of Detroit as a phoenix-like metropolis open to commerce and reinvention. This paper seeks to interrogate the role of regenerative event tourism within a new phase in the city’s touristic, industrial, financial, and land-use history, a phase whose trajectory began in the 2020s with the horizon of the 2030s in view. Overall, economic activity and communication efforts remain centred around the automobile, with Detroit’s industrial heritage undergoing regeneration as a foundational pillar of its transformation. The Henry Ford Museum, the Detroit Auto Show, and the adaptive reuse of former factories are now drawing not only investors, but also new forms of MICE engagement aimed at serving the city, its residents, and inclusive employment strategies. At the heart of this effort are two landmark infrastructures: the fully renovated Cobo Hall—now Huntington Place—and the symbolic Michigan Central Station. These sites, once derelict, are now being woven into curated touristic itineraries, reshaping perceptions of the city through both aesthetic and regenerative lenses. Despite decades of economic, social, environmental, and health crises, Detroit is betting on business tourism and event hosting to attract conventions, visitors, enterprises, and decision-makers—while rebranding itself through the lens of renewed amenities. The development of modern congress centres and an upgraded hotel offering aim to draw international events. At the forefront of this long-term strategy stands the Michigan Central Innovation District – Station (MCID-S), inaugurated in 2024 as a flagship initiative led by the Ford Motor Company. This initiative aspires to support a diverse, multi-ethnic city through a revitalised commercial and cultural offer, while instilling a renewed sense of civic pride around the city’s so-called “Renaissance.” This dynamic is further reinforced by the regeneration of specific neighbourhoods where art, music, and gastronomy contribute to a redefinition of the city's image—closely linked to its emerging MICE identity. Through a mixed-method approach including a social media-based questionnaire and targeted interviews with administrators at MCID-S, Cobo Hall, and Visit Detroit, this study sketches a singular touristic portrait of the metropolis, highlighting the roles of public and private actors and the direct and indirect impacts they generate. These findings illuminate an atypical form of urban reconversion, wherein automobiles, ruins, and event-driven strategies converge to foster renewed appeal. However fragile it may be, this renaissance reveals the transformative potential of post-industrial cities—made visible through a reinvention of their heritage and infrastructures via MICE-based regeneration.Longtemps considérée comme le symbole du déclin industriel américain, Détroit connaît aujourd’hui un renouveau touristique et une attractivité amplifiée par une notoriété entretenue coûte que coûte (malgré la faillite de la ville) à travers un service de communication Visit Detroit qui propose une mise en scène et en récit de la ville du Midwest dans un double discours loisir-culturel et d’affaires concernant son offre touristique. Jadis capitale mondiale de l’automobile, la ville a souffert de la désindustrialisation et d’une crise économique profonde, laissant derrière elle un paysage marqué par la décroissance urbaine et des bâtiments en ruine. Parallèlement au phénomène du « ruin porn », qui valorise l’esthétique des bâtiments abandonnés et qui suscite un engouement particulier chez les photographes et les explorateurs urbains, tout en amenant à des polémiques sur la réalité d’un patrimoine en transition ou d’un tourisme de voyeurisme ; une toute nouvelle stratégie marketing et de reconquête urbaine se fonde à partir de l’organisation d’évènement majeur de type MICE (Meetings, Incentives, Conferences, Exhibitions) classique, mais aussi avec une volonté que ces manifestations soient régénératives et profitables à l’ensemble de la communauté des habitants de la ville, de son centre et de la banlieue (aux forts taux de pauvreté) par l’intermédiaire de visiteurs impliqués-actifs sur le territoire et réceptifs de la nouvelle donne (New Deal) de Détroit. Dans ces conditions, ces stigmates du passé deviennent aujourd’hui des atouts dans une stratégie de reconversion touristique : de nouvelles aménités surgissent ou se réinventent par le biais du tourisme d’affaires et des conventions qui furent dès le XIXe siècle un instrument de développement d’une image dynamique et d’une métropole phœnix propice aux affaires. Nous proposons de s’interroger sur le rôle du tourisme événementiel régénératif dans le cadre d’une nouvelle étape de l’histoire touristique, industrielle et financière – foncière de la métropole américaine depuis les années 2020 avec pour horizon les années 2030. Globalement, l’activité économique et la communication centrées sur l’automobile, avec justement un patrimoine industriel en régénération comme un pilier essentiel de cette transformation, ouvrent des perspectives et hypothèses nouvelles. Le musée Henry Ford et surtout le Detroit Auto Show et les anciennes usines réhabilitées attirent les investisseurs, mais aussi impliquent une nouvelle approche des MICE au service de la ville, des habitants et de l’employabilité de toutes les couches de la société à travers une industrie de l’événementiel reposant sur deux grandes infrastructures modernisées pour le compte d’une croissance durable, le Cobo Hall (Huntington Place) et le landmark (bâtiment-architecture symbolique) Michigan Central Station. Ces vestiges sont progressivement intégrés dans des circuits touristiques que nous analysons, contribuant à changer le regard porté sur la ville par un effet double esthétique et régénératif à plus d’un titre. Malgré des décennies de crises sociales, économiques, financières, environnementales et sanitaires, Détroit mise sur le tourisme d’affaires et l’événementiel pour attirer des manifestations, des visiteurs, des entreprises et des décideurs tout en retirant une nouvelle image de ces aménités. L’ouverture de centres de congrès modernisés et le développement d’une offre hôtelière adaptée visent à attirer des événements internationaux. Le Michigan Central Innovation District - Station (MCID-S) et sa récente inauguration en 2024 est le fer de lance de cette stratégie à long terme d’un groupe, Ford*, voulant soutenir une ville diversifiée et multiethnique à travers une offre commerciale et culturelle renouvelée et d’insuffler le sentiment de fierté de tous les habitants pour la « Renaissance » de la ville. Cette dynamique est consolidée par la régénération de certains quartiers, où l’art, la musique et la gastronomie redéfinissent l’image de la ville associée étroitement au MICE. Ainsi, à travers un questionnaire envoyé sur les réseaux sociaux et un autre plus ciblé sur les administrateurs du MCID-S, Cobo Hall et Visit Detroit, nous aboutissons à un portrait touristique singulier de cette métropole et de leurs acteurs de l’événementiel qu’ils soient publics ou privés ainsi que des impacts directs, indirects produits. Ils illustrent une reconversion urbaine atypique, où l’automobile, les ruines et l’événementiel se complètent pour entamer une nouvelle attractivité. Cette renaissance, bien que fragile, témoigne du potentiel de transformation des villes post-industrielles à travers une réinvention de leur patrimoine et de leurs infrastructures par les MICE
Transport sédimentaire dans un bassin versant à régime montagnard sous influence méditerranéenne : retour d'expérience de 7 années de suivi et modélisation des flux en contexte de changement climatique (Roya, Alpes-Maritimes, France)
No full textInternational audienceAs other rivers of the Mediterranean Riviera, the Roya is a characterized by hydrological extremes, high sediment fluxes and dense valley floor land use. The research undertaken in the catchment aimed at characterizing and quantifying sediment fluxes at catchment scale, to define a prospective modelling of sediment fluxes in climate change context. Field monitoring since 2016 notably included RFID tracking and passive seismic monitoring. A 1000 years-return period flood that occurred on 2020/10/02 was a unique opportunity to analyze the system trajectory after such an intense event. The average and maximum distances of sediment transport in relation with the duration of the study and the excess unit stream power confirm that the Roya is particularly dynamic. The post-flood trajectory suggests increased mobility but will be maintained only with sufficient hydrology in the next years. This extreme event enables to analyze sediment fluxes at catchment scale in climate change context while questioning the resilience rhythm of the system.La Roya est un exemple caractéristique des cours d’eau de la Riviera méditerranéenne, avec une hydrologie contrastée et des flux sédimentaires importants, et une occupation dense du fond de vallée. Nous présentons ici une synthèse des recherches réalisées dans le bassin versant depuis 2016, qui ont essentiellement visé à caractériser et quantifier les dynamiques sédimentaires à l'échelle du bassin versant, pour dégager une vision prospective du devenir de ces flux à moyen terme. Le suivi de terrain a notamment couplé du traçage RFID et de la sismique passive. La tempête Alex du 02/10/2020 a donné l’occasion unique de capturer un tel événement et d'analyser la trajectoire du système après une crue de période de retour millénale sur la partie amont du bassin. Les analyses menées sur les distances moyennes et maximales de transport, la durée de suivi et la puissance spécifique, placent résolument la Roya dans la gamme des cours d’eau à transport solide intense, même sans inclure l’événement extrême d’octobre 2020. La trajectoire du système post-crue suggère une mobilité accrue et toujours d’actualité après déstructuration du lit. Un progressif retour à une simplification du profil en travers sous l’effet de la purge sédimentaire du système peut s’envisager, mais reste fortement conditionnée par l’hydrologie à venir. L’événement extrême du 02/10/2020 permet d’approfondir l’évaluation des flux sédimentaires en Roya en contexte de changement climatique en questionnant le rythme de résilience du système
An algebraic framework for geometrically continuous splines
No full text46 pages, 5 figures, 1 tableInternational audienceGeometrically continuous splines are piecewise polynomial functions defined on a collection of patches which are stitched together through transition maps. They are called -splines if, after composition with the transition maps, they are continuously differentiable functions to order on each pair of patches with stitched boundaries. This type of splines has been used to represent smooth shapes with complex topology for which (parametric) spline functions on fixed partitions are not sufficient. In this article, we develop new algebraic tools to analyze -spline spaces. We define -domains and transition maps using an algebraic approach, and establish an algebraic criterion to determine whether a piecewise function is -continuous on the given domain. In the proposed framework, we construct a chain complex whose top homology is isomorphic to the -spline space. This complex generalizes Billera-Schenck-Stillman homological complex used to study parametric splines. Additionally, we show how previous constructions of -splines fit into this new algebraic framework, and present an algorithm to construct a bases for -spline spaces. We illustrate how our algebraic approach works with concrete examples, and prove a dimension formula for the -spline space in terms of invariants to the chain complex. In some special cases, explicit dimension formulas in terms of the degree of splines are also given
Wave-kinetic dynamics of forced-dissipated turbulent internal gravity waves
No full text6 pages, 5 figures, 1 supplementary materialInternational audienceInternal gravity waves are an essential feature of flows stratified media, such as oceans and atmospheres. To investigate their dynamics, we perform simulations of the forced-dissipated kinetic equation describing the evolution of the energy spectrum of weakly nonlinear internal gravity waves. During the early evolution, the three well-known non-local interactions, the Elastic Scattering, the Induced-Diffusion, and the Parametric Sub-Harmonic Instability, together with the Super-Harmonic Instability play a prominent role. In contrast, local interactions are responsible for anisotropic energy cascade on longer time scales. We reveal emergence of a condensate at small horizontal wavevectors that can be interpreted as a pure wave-wave interaction-mediated layering process. We also observe the dynamical formation of an energy spectrum compatible with the Garrett-Munk prediction
Study and optimization of the selectivity of an odorant binding protein-based bioelectronic nose
No full textInternational audienceOver the past two decades, the use of odorant-binding proteins (OBPs) for the development of biosensors and bioelectronic noses (bioeNs) aimed at detecting and analyzing volatile organic compounds (VOCs) has been the subject of considerable research. However, there is a lack of fundamental studies for better understanding the interaction between OBPs and VOCs in gas phase. In this work, we investigated the effect of two key factors, namely relative humidity (RH) level and immobilization technique, on the selectivity of two OBP-based biosensors in gas phase. Concerning the effect of RH, the results showed that our active OBP (wild-type rat OBP3) lost its selectivity at 0% RH but retained good selectivity at 30% and 50% RH. To better understand the effect of this parameter, the hydration mechanism of the OBP was studied both experimentally and through molecular dynamics simulations. The effect of a cysteine residue, genetically added to the N-terminus of OBPs to control their orientation after immobilization on the chip, was evaluated. A significant reduction in selectivity was observed in the absence of cysteine. As expected, the introduction of this amino acid enabled to control the orientation of OBPs, making their binding pocket more accessible to VOCs and favoring specific interactions. Furthermore, we demonstrated that combining OBP-based biosensors with different properties can improve the discrimination capability of our bioeN. Finally, the ability of our system to detect essential oil vapors was tested, providing preliminary evidence that our bioeN is capable of detecting VOCs in complex media
Hidden quantum correlations in cavity-based quantum optics
No full textInternational audienceIn multimode optical systems, the spectral covariance matrix encodes all the information about quantum correlations between the quadratures of Gaussian states. Recent research has revealed that, in scenarios that are more common than previously thought, part of these correlations remain inaccessible to standard homodyne detection scheme. Formally, this effect can be attributed to a non-real spectral covariance matrix. In this work, we provide a systematic framework and explicit criteria for identifying experimental configurations leading to such a behavior. This study will facilitate the proper exploitation and optimal engineering of CV quantum resources
Quantifying and combining uncertainty for improving the behavior of Digital Twin Systems
No full textInternational audienceUncertainty is an inherent property of any complex system, especially those that integrate physical parts or operate in real environments. In this paper, we focus on the Digital Twins of adaptive systems, which are particularly complex to design, verify, and optimize. One of the problems of having two systems (the physical one and its digital replica) is that their behavior may not always be consistent. In addition, both twins are normally subject to different types of uncertainties, which complicates their comparison. In this paper we propose the explicit representation and treatment of the uncertainty of both twins, and show how this enables a more accurate comparison of their behaviors. Furthermore, this allows us to reduce the overall system uncertainty and improve its behavior by properly averaging the individual uncertainties of the two twins. An exemplary incubator system is used to illustrate and validate our proposal
Exact continuous relaxations of l0-regularized criteria with non-quadratic data terms
No full textInternational audienceWe propose a new class of exact continuous relaxations of l0-regularized criteria involving non-quadratic data terms such as the Kullback-Leibler divergence and the logistic regression, possibly combined with an l2 regularization. We first prove the existence of global minimizers for such problems and characterize their local minimizers.Then, we propose the l0 Bregman Relaxation (B-rex), a continuous approximation of the l0 pseudo-norm defined in terms of suitable Bregman distances, which leads to an exact continuous relaxations of the original l0-regularized problem in the sense that it does not alter its set of global minimizers and reduces the non-convexity by eliminating certain local minimizers. Both features make the relaxed problem more amenable to be solved by standard non-convex optimization algorithms. In this spirit, we consider the proximal gradient algorithm and provide explicit computation of proximal points for the B-rex penalty in several cases. Finally, we report a set of numerical results illustrating the geometrical behavior of the proposed B-rex penalty for different choices of the underlying Bregman distance, its relation with convex envelopes, as well as its exact relaxation properties in 1D/2D and higher dimensions
On the ε-Euler-Maruyama scheme for time-inhomogeneous jump-driven SDEs
No full textInternational audienceWe consider a class of general SDEs with a jump integral term driven by a time-inhomogeneous Poisson random measure. We propose a two-parameters Euler-type scheme for this SDE class and prove an optimal rate for the strong convergence with respect to the -norm and for the weak convergence, considering integration over uniform time-steps.One of the primary issues to address in this context is the approximation of the noise structure when it can no longer be expressed as the increment of random variables. We extend the Asmussen--Rosiński approach to the case of a fully dependent jump coefficient and time-dependent Poisson compensation, handling contribution of jumps smaller than with an appropriate Gaussian substitute and exact simulation for the large jumps contribution. For any , under hypotheses required to control the -moments of the process, we obtain a strong convergence rate of order . Under standard regularity hypotheses on the coefficients, we obtain a weak convergence rate of , where is the Blumenthal--Getoor index of the underlying Lévy measure. We compare this scheme with the Rubenthaler's approach where the jumps smaller than are neglected, providing strong and weak rates of convergence in that case too. The theoretical rates are confirmed by numerical experiments afterwards. We apply this model class for some anomalous diffusion model related to the dynamics of rigid fibres in turbulence