Publications scientifiques de l'Université de Reims Champagne-Ardenne
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Event-Driven Control of Hybrid Systems Using Batches Petri Nets: Application to High Throughput Manufacturing Systems
No full textInternational audienceThe problem considered in this work concerns the control of hybrid systems, studied from the discrete event systems theory viewpoint. The objective is to compute a transient control trajectory for reaching a steady state from a given initial state. The hybrid systems are modeled by a class of hybrid Petri nets called controlled generalized batches Petri nets, which introduce variable delays on continuous flows for modeling and analysis of dynamical systems. The key contributions of this study are as follows: two event-driven control strategies are proposed for reaching a target steady state, offering advantages in terms of control actions and time performance. These strategies are based on ON/OFF state transitions, with the firing flow either limited to its steady flow or maximal flow; two algorithms are presented to implement these control strategies effectively; a case study of a bottling production line, a high throughput manufacturing system, is provided, demonstrating the application of the proposed methods and evaluating their efficiency in terms of time performance and the number of generated events. Note to Practitioners—In this work, two event-driven control strategies for reaching a steady state from a given initial state are presented. We use controlled generalized batches Petri nets that are suitable discrete event formalism for the modeling of complex systems such as transportation systems, high throughput production lines and, crowds behavior. This Petri net could model groups of moving entities with given forms (speed, density, length), which allows to consider variable delays of transfer elements due to congestion or groups merging. The objective is to reach a target steady state characterized by constant flows and also particular forms of the entities groups. This is a challenging issue because the existing formalisms and methods usually allow to reach a given steady setting without considering the forms of the entities groups. The proposed control strategies could be used, for example, during a recovery mode in order to reach the steady state after a system’s shutdown, failure or malicious attack. Their effectiveness is shown on the Perrier mineral water bottling production line
Anticipating bioeconomy transitions: An integrative systems approach for exploring uncertain futures
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German Legal dogmatics and its contribution to the "scientificity" of law. An epistemological analysis of a law creation and application process
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La variété italienne comme seuil dramaturgique chez Vincent Macaigne et Anne-Sophie Pauchet
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Root certification using disk arithmetic
No full textSplitting algorithms provide a list of all the roots of a polynomial, however, most numerical implementations lack the proper framework to provide certification, i.e. a computer assisted proof that the list is correct. This article adresses this issue, regardless of the underlying splitting algorithm, with minimal computational overhead. To ensure a strict control of the computational errors that is robust enough to withstand intensive iterations, we revisit and extend the theory of disk arithmetic. We also present two results, one regarding the localization of roots and one regarding the convergence of numerical refinements using Newton's method. The assumptions of both results can be certifiably checked numerically, using disk arithmetic and IEEE 754 compliant roundings. We release a compagnon in C-code that implements those results and has been used in [MV2025] to provide a computer assisted certification of the first ever tera-scale splitting
Optimizing CO2 emission estimates in Paris through enhanced urban atmospheric monitoring
No full textInternational audienceAs part of the EU-funded PAUL project (ICOS Cities), the metropolitan area of Paris, in parallel with Munich and Zurich, has been instrumented with various observing systems to define the most-suitable approaches for CO2 emissions monitoring. This effort is underpinned by an extensive urban atmospheric monitoring network, comprising nine towers equipped with high-accuracy and mid-cost sensors designed to capture variations in atmospheric concentrations. Driven by 1-km meteorological fields (from WRF), the Stochastic Time-Inverted Lagrangian Transport (STILT) model has been employed for backward simulations of CO2 enhancements based on state-of-the-art high-resolution inventories for 2023. Transport errors have been significantly reduced ( from about 4-5 m/s to 1~2 m/s) through the assimilation of three-dimensional wind profiles obtained from multiple Lidar data over Paris (Urbisphere project), using 3DVar data cycling assimilation. Fossil fuel emissions (TNO, AirParif) and biogenic emissions (using offline VPRM MODIS and Sentinel-2) serve as prior inventories in our inverse modeling framework. This framework employs a Bayesian inversion technique producing hourly fluxes with time-varied adaptive mesh grids (1 km in the downtown area, gradually aggregated to 100 km across the region), balancing computational efficiency with inversion accuracy near monitoring sites. However, direct comparisons revealed systematic discrepancies in the inversion results, particularly in the adjustments between anthropogenic and biogenic emissions. To address this, radiocarbon (14C) observations from two Parisian sites were incorporated as additional constraints, improving the partitioning of fossil fuel and biogenic contributions in the inversion
La preuve et la publicité : quelles perspectives pour le notaire ? Interventions des étudiants du Master 2 Droit notarial de l'université de Reims
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Ni dire ni taire
No full textInternational audienceDans ce chapitre (le dernier de l'essai), nous raisonnons depuis nos propres pratiques le faire du poème en vidéo
Améliorer la santé au travail et la motivation dans le secteur médico-social par le biais d’une formation à la théorie de l’autodétermination : une étude quasi expérimentale menée dans le cadre du programme « Un chez soi d’abord »
No full textInternational audienceL’objectif du dispositif français « un chez soi d’abord (UCSD) » est d’accompagner les publics précaires (sans-abris) atteints des troubles mentaux sévère au travers du logement. Inspiré des modèles nord-américains du logement d’abord, ce dispositif a pour particularité de fonder ses pratiques sur les principes du rétablissement en santé mentale (Deegan, 1997) et sur les principes de la théorie de l’autodétermination (TAD ; Ryan et Deci, 2017). La TAD étant théorie de la motivation humaine qui examine le processus par lequel les facteurs biologiques et socio-culturels renforcent ou affaiblissent les capacités inhérentes à la croissance psychologique, à l’engagement et au bien-être. Ainsi, le dispositif UCSD vient en contre-pied du modèle classique d’accompagnement social dont les pratiques seraient perçus comme frustrants à l’égard des besoins psychologique au sens de la TAD. Si les différents professionnels présents au sein de ces structures (e. g. Infirmière, éducateurs) sont formés aux grands principes de ces approches, ils ne sont toutefois pas formés aux détails de la TAD et de ce que cela implique pour l’accompagnement de ce public particulier, ni accompagnés dans l’intégration de ces principes théoriques à leur pratique et identité professionnelle. À partir d’une recherche quasi-expérimentale longitudinale, cette étude a pour objectif de tester l’efficacité d’une formation approfondie à la TAD. Cette formation consiste en une journée complète de formation suivie de trois séances d’analyse de pratiques étalées sur trois mois afin de favoriser une intégration des connaissances. Afin de tester les effets de cette formation dispensée, trois groupes de participants sont créés : Un premier groupe de professionnels du dispositif UCSD à qui la formation approfondie à la TAD a été délivré ; un second groupe avec les salariés UCSD qui n’ont pas suivi la formation ; puis un dernier groupe de professionnel n’exerçant pas dans le dispositif UCSD mais dans une structure ayant le même type d’activité (i.e., relogement de publics sans abris). Les différents groupes ont eu à répondre à une série de mesures à deux temps de mesures (T1 avant et à la fin de la formation, T2 3 mois après le T1) de santé au travail (i.e., satisfaction au travail, sens du travail, épuisement professionnel, engagement au travail) mais aussi sur l’identification, la motivation au travail et l’état des besoins psychologique