HAL Portal de Univ. Gustave Eiffel
Not a member yet
72847 research outputs found
Sort by
On Arrangements of Quadrics in Decomposing the Parameter Space of 3D Digitized Rigid Motions
No full textInternational audienceComputing the arrangement of quadrics in 3D is a fundamental problem in symbolic computation, with challenges arising when handling degenerate cases and asymptotic critical values. State-of-the-art methods typically require a generic change of coordinates to manage these asymptotes, rendering certain problems intractable. A specific instance of this challenge appears in digital geometry, where comparing 3D shapes up to isometry requires applying a 3D rigid motion on and mapping the result back to , a process typically achieved via a digitization operator. However, such motions do not preserve the topology of digital objects, making the analysis of digitized rigid motions crucial. Our main contribution is the decomposition of the 6D parameter space of digitized rigid motions for image patches of radius up to three. This problem reduces to computing the arrangement of up to 741 quadrics, some of which are degenerate. To address the computational challenges, we introduce and implement a new algorithm for computing arrangements of quadrics in 3D, specifically designed to handle degenerate directions and asymptotic critical values. This approach allows us to overcome the limitations of existing methods, making the problem tractable in the context of digital geometry
LES EXISTENCES CONTRARIÉES DU DOSSIER MÉDICAL PARTAGÉ (DMP). Retour sur une innovation numériqueau long cours
No full textInternational audienceThis article traces the little-known history of the shared medical record (dossier médical partagé - DMP), seen as an innovation whose trajectory, and especially its extraordinary genesis, warrants analysis. The authors look at the representations, decisions and practices that have governed the DMP’s multiple development projects at national level, from its creation in the 2000s to the recent project to integrate it into the “Mon espace santé” portal, which materialized in 2022. The DMP is characterized by cyclical phases of difficulties, suspensions and relaunching, and, 20 years after its first launch, by the fact that it has not yet fully stabilized or achieved its initial objectives. Paying attention to the multiple temporalities of the innovation process, the analysis brings to light the two major conceptions of healthcare IT that have underpinned the development of the DMP. Italso highlights the importance of the political and institutional context, as well as the instability of the project's governance and the role of several of its actors, which contributed to hampering the translation efforts undertaken.L’article retrace l’histoire encore mal connue du dossier médical partagé (DMP) en analysant les représentations, les décisions et les pratiques qui ont présidé, à l’échelle nationale, à ses multiples projets de développement, depuis sa création au cours des années 2000 jusqu’à son récent projet d’intégration au sein du portail « Mon espace santé », qui s’est concrétisé en 2022. La perspective d’analyse invite à considérer le DMP comme une innovation dont il importe de retracer la trajectoire et, notamment, l’extraordinaire genèse. Le dossier médical partagé a en effet pour caractéristique d’avoir donné lieu à des phases cycliques de difficultés, d’arrêt et de relance, et, 20 ans après son démarrage, de ne pas être totalement stabilisé et de ne pas avoir encore atteint les objectifs fixés initialement. En prêtant attention aux temporalités multiples du processus d’innovation, l’analyse met au jour les deux grandes conceptions de l’informatique de santé qui ont sous-tendu les modalités de développement du DMP. Elle met également en évidence l’importance du contexte politique et institutionnel, ainsi que l’instabilité des modalités de gouvernance du projet et le rôle joué par plusieurs de ses acteurs, qui ont contribué à entraver les efforts de traduction mis en oeuvre
Transports et mobilités : autonomisation ou pleine affiliation à l’histoire des sciences et des techniques ?
No full textInternational audienc
Une nouvelle définition pour les treillis m-cambriens
No full textThis work has been accepted as an extended abstract for the FPSAC 2025 conference. A long version of this work will be available later.International audienceThe Cambrian lattices, introduced in (Reading, 2006), generalize the Tamari lattice to any choice of Coxeter element in any finite Coxeter group. They are further generalized to the m-Cambrian lattices (Stump, Thomas, Williams, 2015). However, their definitions do not provide a practical setup to work with combinatorially.In this paper, we provide a new equivalent definition of the m-Cambrian lattices on simple objects called m-noncrossing partitions, using a simple and effective comparison criterion. It is obtained by showing that each interval has a unique maximal chain that is c-increasing, which is computed by a greedy algorithm. Our proof is uniform, involving all Coxeter groups and all choices of Coxeter element at the same time.This work has been accepted as an extended abstract for the FPSAC 2025 conference. A long version of this work will be available later.Les treillis cambriens, introduits dans (Reading, 2006), généralisent le treillis de Tamari à tout choix d'élément de Coxeter dans tout groupe de Coxeter fini. Ils ont été généralisé en les treillis m-cambriens (Stump, Thomas, Williams, 2015), mais ces définitions ne fournissent pas de modèle combinatoire pratique.Dans cet article, nous donnons une nouvelle définition des treillis m-cambriens sur des objets simples appelés m-partitions non croisées, avec un critère de comparaison simple et efficace. Elle est obtenue en montrant que chaque intervalle a une unique chaîne maximale c-croissante, calculée par un algorithme glouton. Notre preuve est uniforme et implique tous les groupes de Coxeter et tous les choix d'élément de Coxeter à la fois.Cet article a été accepté comme résumé étendu pour la conférence FPSAC 2025. Une version longue de ce travail sera disponible ultérieurement
EFAS score – Validation of Mandarin and Cantonese versions by the Score Committee of the European Foot and Ankle Society (EFAS)
No full textInternational audienceBackground: The Score Committee of the European Foot and Ankle Society (EFAS) developed, validated, and published the EFAS Score in 14 languages. Currently, the Mandarin and Cantonese versions completed data acquisition and underwent further validation. Methods: The data were collected pre-operatively and post-operatively at a minimum follow-up of 3 months and mean follow-up of 6 months. Item reduction, scale exploration, confirmatory analyses and responsiveness were executed using classical test theory and item response theory. Results: The internal consistency was confirmed in the Mandarin/Cantonese versions (Cronbach’s Alpha 0.83/0.80). The Standard Error of Measurement (SEM) was 0.36/0.35 and is similar to other language versions. Between baseline and follow-up, 80 %/84 % of patients showed an improvement on their EFAS score, with good responsiveness (effect size 1.34/1.52). Conclusions: The Mandarin and Cantonese EFAS Score versions were successfully validated in patients with a wide variety of foot and ankle pathologies. All score versions are freely available at www.efas.ne
Matching random colored points with rectangles (Corrigendum)
No full textGiven n>0, let be a set of points, chosen uniformly at random. Let be a random partition, or coloring, of in which each point of is included in uniformly at random with probability . Corujo et al.~(JOCO 2023) studied the random variable equal to the number of points of that are covered by the rectangles of a maximum matching of using pairwise-disjoint rectangles. Each rectangle is axis-aligned and covers exactly two points of of the same color. They designed a deterministic algorithm to match points of , and the algorithm was modeled as a discrete stochastic process over a finite set of states. After claiming that the stochastic process is a Markov chain, they proved that almost surely for large enough. The issue is that such a process is not actually a Markov one, as we discuss in this note. We argue this issue, and correct it by obtaining the same result but considering that the stochastic process is not Markov, but satisfies some kind of first-order homogeneity property that allows us to compute its marginal distributions
Interest rate pass-through in the euro area: After two decades of crises, a return to normality?
No full textdiv>This paper investigates the monetary policy transmission in the euro area countries over two decades of single currency. This period was marked by financial, sovereign debt and health crises, as well as by episodes of low and high inflation rates. To face these challenges, the European Central Bank used both conventional and unconventional monetary policy measures of an unprecedented scale. We study whether, and if so to what extent, these different events have affected the transmission of monetary policy to retail bank interest rates in several euro area countries. Our results confirm previous findings, namely that interest rate passthrough has been influenced by the various crises that occurred over the course of the euro area existence. After the pandemic, however, we observe a return to a near complete transmission of monetary policy impulses to lending rates, likely under the effect of a reduction in excess liquidity
How scientific networks can help advancing both scientific knowledge and public policies: the case study of the “Plastics, Environment and Health” network
No full textInternational audienceThe “Plastics, Environment and Health” research network (groupement de recherche, GDR) created in 2019 gathers the French scientific community working on plastic pollution in all environments (soil, air, water) and their impact on ecosystems and human health. The scientific objective is to rapidly increase knowledge on plastic pollution by supporting collaboration of researchers from different fields such as ecotoxicology, chemistry, physics, microbiology, oceanography and social science. Research is carried out at each stage of the plastic life cycle, (from resource extraction all the way to removal and remediation) and across the entire air-soil-water continuum, integrating transfers of both plastic particles (macro, micro- and nanoplastics) and plastic chemicals (e.g., additives) between different environmental compartments. In this context, the GDR supports the development of multi-scale and transdisciplinary approaches across three main axes: Axis 1 - Air-soil-water continuum: contamination levels and transfer between compartments; Axis 2 - Interactions and transformation of plastics in environmental compartments and living organisms; Axis 3. Plastic pollution risk assessment for ecosystems and human health. To do so, the GDR’s actions focus on (1) training and sharing of scientific knowledge, including developments towards innovation, (2) support for collaboration and interdisciplinarity between network members, (3) dissemination, structuring of the community and its national and international influence, and (4) support for public policy and/or decision-making by strengthening the link between scientists, decision-makers and the plastic industry. To date the research network includes more than 50 laboratories spread across France and over 300 scientists in the field of physics, chemistry, biology, ecology and social sciences. Such a network constitutes a powerful tool to build robust science-based knowledge significantly contributing to the international effort, to disseminate state-of-the-art scientific advances and research priorities needed to tackle plastic pollution to Society and to inform policy makers. This talk will present the French taskforce addressing 'Plastic, Environment, and Health' within the national research network, where the entire community works collaboratively to tackle the urgent challenges of plastic pollution, its environmental consequences, and the associated risks to human health. We will also discuss the importance of building a French-speaking community to support multilingualism in international political science interactions
Travailler sur et avec une ville sur le temps long : choix méthodologiques et posture du/de la chercheur.e. Exemple du projet de recherche-action Care et cAdre de vie en BAnlieueS (CABAS) à Gennevilliers (92)
No full textCommunication orale lors d'un séminaire méthodologique du Lab'UrbaNational audienceMa communication s’appuie sur le projet de recherche-action CABAS pour Care et cAdre de vie en BAnlieueS (https://cabas.hypotheses.org/). Cette recherche s’intéresse de façon globale au cadre de vie (traitements paysagers, offre alimentaire, conditions de vie santé et bien-être...) des populations comme à l’attention portée aux territoires de banlieues et à leurs habitant.es. Il s’agit, en mobilisant le concept de care en géographie sociale et de la santé, d’interroger les modalités du prendre soin des personnes et des territoires des espaces dits périphériques aux grandes métropoles. À ce jour, l’équipe est composée de chercheur.es (en géographie sociale, de la santé, du commerce...), de professionnel.les locaux (agent.es de la collectivité, élu.es, salarié.es associatifs), d’artistes (compagnie d’arts de rue La Commune mesure, danseuse et chorégraphe Elodie Escarmelle) et d’habitantes.Cette communication se concentrera sur le volet santé du projet et son déploiement à Gennevilliers (92). Celui-ci associe plus particulièrement l’équipe de recherche à la Direction municipale de la santé et de la prévention de la ville de Gennevilliers (via la responsable Service Prévention santé et le coordinateur de l’observatoire local de santé), à la Direction générale transition écologique de la commune (via la cheffe de projet alimentation durable) et le CCAS (Centre Communal d’Action Sociale).Ma proposition visera avant tout de discuter la posture particulière d’une chercheure travaillant avec et sur le territoire de Gennevilliers depuis de nombreuses années. Il s’agira en effet de discuter la tension inhérente à un partenariat qui s’ancre dans le temps long avec, ici, la ville de Gennevilliers. Cette tension renvoie à la nécessité de s’appuyer sur des relations de travail/interconnaissances fortes pour mener à bien une recherche-action (ex : temps long de la construction d’une compréhension mutuelle entre différents membres du projet ; temps long nécessaire à la connaissance fine du territoire afin de bien comprendre les enjeux locaux, les actions des partenaires, leurs histoires...) ; mais aussi aux limites qu’impliquent de travail sur le long terme ( ex : trop (?) forte connaissance du terrain et de ces acteur.trices, familiarité avec les acteurs qui sont à la fois sujet des observations et partenaires, manque de recul ...). Je propose aussi de discuter la posture particulière d’une chercheuse à la fois observatrice et actrice engagée dans des dynamiques locales de lutte contre les inégalités de santé (ex : « influence » de la recherche sur des politiques locales via la co-construction des sujets de stage, via le montage de projet avec d’autres partenaires...). Mon intervention permettrait également d’expliciter certains choix et déploiement des méthodes qui apparaissent particuliers au format et objectif de cette recherche-action. Bien qu’à ce stade du projet, des méthodes relativement classiques des sciences sociales soient mobilisées (entretiens semi-directifs, observations participantes, diagnostic territorial mené par des stagiaires de Master...) le projet a vocation à développer des formats plus hybrides (ex : partenariat avec une danseuse chorégraphe et un groupe de femmes), et ce, en s’appuyant sur ce qui a pu être expérimenté dans un précédent programme de recherche-action participative menée à Gennevilliers (La ville côté femmes 2014-2020). Enfin, ces réflexions nous inciteront aussi à questionner la réplicabilité et la transposabilité des méthodologies de recherche-action
Assessing the impact of crisis cell decisions during flash flood
No full textInternational audienceCatastrophic weather-related events, such as flash floods, require efficient decisions to reduce people’s exposure while avoiding unnecessary decisions. To provide efficient decisions, a crisis management cell composed of decision-makers and experts must be able to centralize information and make relevant choices. Our study proposes an agentbased model which can be used to assess various strategies for flood crisis management. Our study focuses on the application of several decisions taking into account both their interactions and the time of their implementation. We model people’s behaviors during their daily activities and their adaptation to flooding and to the authorities’ decisions with the GAMA platform. Preliminary results indicate that the time of decision implementation impacts people’s exposure to flooding and that combining specific decisions enhances the efficiency of crisis management. This approach helps limit ineffective decisions and select those that provide a trade-off between flood exposure and daily activities’ disruption