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Variabilité des coûts hospitaliers après 15 ans d’introduction de la T2A
No full textLa logique de construction de l’homogénéité des groupes de GHM par niveau de sévérité ne rencontre pas la réalité empirique de construction de ces groupes. En effet, les intervalles de confiance des coûts moyens se confondent ou se chevauchent largement ; L’amplitude des intervalles varie aléatoirement, sans logique apparente. Elle ne varie pas en fonction des degrés de sévérité. La conclusion est que la construction empirique du raffinement des groupes ne permet pas d’éviter la sélection ou l’écrémage des patients. Par ailleurs, lorsque la construction du groupe de racine de GHM se confond avec un acte précis, le coût à rembourser se confond avec un paiement à l’acte ; Lorsque la construction du groupe de racine de GHM ne se confond pas avec un acte précis, on a un remboursement à l’activité. On en conclut donc qu’il n’y a pas eu d’évolution probante de l’homogénéité des groupes GHM au cours de la période 2013-2020
Bridging Human Concepts and Computer Vision for Explainable Face Verification
No full textWith Artificial Intelligence (AI) influencing the decision-making process of sensitive applications such as Face Verification, it is fundamental to ensure the transparency, fairness, and accountability of decisions. Although Explainable Artificial Intelligence (XAI) techniques exist to clarify AI decisions, it is equally important to provide interpretability of these decisions to humans. In this paper, we present an approach to combine computer and human vision to increase the explanation's interpretability of a face verification algorithm. In particular, we are inspired by the human perceptual process to understand how machines perceive face's human-semantic areas during face comparison tasks. We use Mediapipe, which provides a segmentation technique that identifies distinct human-semantic facial regions, enabling the machine's perception analysis. Additionally, we adapted two model-agnostic algorithms to provide human-interpretable insights into the decision-making processes
L’action dans la recherche et la recherche dans l’action : quelles imbrications ?
No full textInternational audienceL'édition 2023 de la Journée des jeunes chercheur.e.s de l'Institut de Géographie de Paris [JIG] souhaitait interroger les liens entre la recherche et les autres contextes de l’action - professionnels, militants, politiques - qu'elle cherche à analyser et avec lesquels, en conséquence, elle interagit, voire s'imbrique. Comment la recherche dialogue-t-elle avec ces dimensions de l’action ? Qu’est-ce qu’elle leur apporte ? L’apport est-il réciproque ou unilatéral ? Comment ces autres milieux se saisissent-ils de la recherche pour la mobiliser en dehors de la communauté scientifique ? Qu’est-ce que la recherche emprunte à d'autres contextes professionnels ? À travers trois sessions, les intervenant.e.s et discutant.e.s de la journée ont discuté les enjeux de positionnement, d'engagement et de militantisme dans les interactions de la recherche avec les sphères de l’action publique et les espaces et les acteurs du terrain. L'intégralité des échanges de cette journée d'étude sont retranscrits dans ces actes
Potential impact of Aeroclipper observations targeting tropical cyclone in the Western Pacific
No full textInternational audienceThe Aeroclipper is a new balloon device that can be attracted and captured by tropical cyclones (TC) and perform continuous in situ measurements at the air–sea interfaces. To estimate the potential effect of Aeroclipper observations on the analysis of TCs, virtual Aeroclipper observations targeting TC Haima (October 2016) were synthesized using an idealized surface pressure distribution and best track data and were assimilated using an ensemble data assimilation system. Results show that the assimilation of Aeroclipper measurements may provide a more accurate representation of the TC pressure, wind, and temperature in analyses. This also leads to improved precipitation around the Philippines. The ensemble spread shows that the Aeroclipper measurement assimilation has an impact on the analyses that extends into the tropics from the early stages of TC development. These impact signals propagate westward with easterly waves and eastward with large‐scale convective disturbances. Although the underlying mechanisms need to be further examined and tested using real Aeroclipper measurements, the present study shows that these balloons could provide valuable observations to improve the precision of analyses in presence of a TC. This is a first step toward a study of the impact of the Aeroclipper measurement on TC forecast
Overcoming barriers to integrate more justice into climate change policies. Lessons from adaptation policies and flood risk management in Flanders and France
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From Expert Computational Knowledge to Interdisciplinary Communication
No full textInternational audienceIn the contemporary landscape, the fields of cybernetics, artificial intelligence, and digital technology significantly impact society, reshaping production processes, decision-making frameworks, and human behaviors. Training engineers with transversal skills becomes imperative to navigate workflow complexities and communicate across these disciplines. We propose a new learning approach structured around expert prerequisites, integrating AI principles dedicated to Embedded Systems engineering track. Our module focuses on creating an autonomous driving vehicle using an autonomous robot kit, fostering interdisciplinary learning. Real-time demonstrations assess learning outcomes, emphasizing problem-solving skills. Inspired from recent evaluation concept of interdisciplinary assessment. Our evaluation criteria emphasize functionality, integrated idea defense, and written reports. The defense organization scheme fosters positive perceptions of interdisciplinary links
Microphysical Modeling of Water Isotopic Composition in the Asian Summer Monsoon
No full textInternational audienceThe summertime Asian Monsoon (AM) is the single most important contributor to water vapor in the UTLS and overworld stratosphere. Much of that water comes from sublimating ice, but the life cycle of the condensate lofted by overshooting convection is not well understood. We report here on insights into that life cycle derived from the first in-situ measurements of water vapor isotopic composition over the Asian Monsoon. The Chicago Water Isotope Spectrometer (ChiWIS) flew on high-altitude aircraft in the monsoon center during the StratoClim (2017) campaign out of Nepal, and in monsoon outflow during ACCLIP (2022) out of South Korea. Both campaigns sampled a broad range of convective and post-convective conditions, letting us trace how convective ice sublimates, reforms, and leaves behind characteristic isotopic signatures. We use isotopic models, along with TRACZILLA backtrajectories and convective interactions derived from cloud-top products, to follow the evolving isotopic composition along flight paths in both campaigns. Results support the wide diversity of isotopic enhancement seen in both campaigns and show how temperature cycles downstream of convective events modify environmental isotopic compositions
Dynamics of diabatically forced anticyclonic plumes in the stratosphere
No full textInternational audienceAbstract A new class of vortices has been observed in the stratosphere following extreme wildfires (Canada 2017, Australia 2020) and volcanic eruptions (Raikoke 2019). These vortices are long‐lived mesoscale anticyclones (hundreds to 1,000 km in diameter) trapping plumes of aerosols and combustion/volcanic compounds. Owing to their unusual composition, these anticyclonically trapped plumes (ATPs) are associated with a significant radiative heating, which fuels their ascent through the stratosphere. This article investigates the dynamics of ATPs using two complementary approaches: analytically, in a potential vorticity (PV) perspective, and through idealised numerical simulations with the Weather Research and Forecasting (WRF) model. In both cases, we consider the vortical flow forced by a heating Lagrangian tracer. By reformulating the problem in the potential radius–potential temperature coordinate system introduced for tropical cyclones, we first clarify that ATP formation is concomitant with the injection of air into the stratosphere at extratropical latitudes. Then, we derive a set of simplified one‐dimensional equations describing the subsequent evolution of the flow after the injection. The equation obtained for the tracer is a variant of the classical Burgers' equation. In qualitative agreement with the three‐dimensional WRF simulations, this theoretical model predicts that ATPs develop an upper tracer front associated with sustained near‐zero anticyclonic PV, followed by a smooth tracer tail of cyclonic PV. Radiative relaxation of the temperature perturbations induced by the anticyclone and the presence of an initial PV anomaly tend to stabilise ATPs during their ascent. Finally, we note that the theory predicts a similar relationship between the plume and anticyclonic PV for cooled ATPs, which is supported by three‐dimensional simulations and may apply to the 2022 Hunga volcanic plume
Exploring two regimes of water mobility in unsaturated expansive clay using NMR relaxometry
No full textInternational audienceThe hydration behaviour of unsaturated expansive clays, crucial for applications such as radioactive waste management, remains a challenging and incompletely understood phenomenon given the complexity of characterizing their pore network dynamics upon water absorption. The evolution of porewater populations, distinguished as immobile adsorbed water attached to the clay particles surface and capillary water, presumably governs the kinetics of water mobility in wetting or drying processes.Nuclear Magnetic Resonance (NMR) relaxometry experiments have reported the increase of water mobility during the wetting process of expansive clays but the evolution of water populations remained unidentified. This study presents relaxation time distributions and relaxation time maps found for a bentonite/sand mixture (with Na-montmorillonite) at various relative humidities, reproducing its hydration. Valuable insights into particular experimental procedure, data-treatment and interpretation for expansive clay are provided. Relaxation times in Na-montmorillonite highlighted a two-regime evolution as a function of water content, in accordance to models, featuring the properties of adsorbed water, which is considered fully dominant during the first regime (relative humidity lower than 90%).An empirical model reproducing the two-regime dependance of water content on relaxation times was proposed. Moreover, a new formulation enabled quantifying the adsorbed water fraction in expansive clay from relaxation time measurements. Finally, the porewater populations were quantified for Na-montmorillonite as a function of water content, demonstrating strong agreement with supercooling observations in freezing experiment
Summer Deep Depressions Increase Over the Eastern North Atlantic
No full textInternational audienceMid-tropospheric deep depressions in summer over the North Atlantic are shown to have strongly increased in the eastern and strongly decreased in the western North Atlantic region. This evolution is linked to a change in baroclinicity in the west of the North Atlantic ocean and over the North American coast, likely due to the increased surface temperature there. Deep depressions in the Eastern North Atlantic are linked to a temperature pattern typical of extreme heat events in the region. The same analysis is applied to a sample of CMIP6 model outputs, and no such trends are found. This study suggests a link between the observed increase of summer extreme heat events in the region and the increase of the number of Atlantic depressions. The failure of CMIP6 models to reproduce these events can consequently also reside in an incorrect reproduction of this specific feature of midlatitude atmospheric dynamics. Plain Language Summary Extreme temperatures events in Western Europe have been rising fast, and current global climate models are not able to reproduce this excess. There are different hypotheses to explain this discrepancy. One is that the large-scale atmospheric dynamics, responsible for the local weather, is not correctly represented by the models: indeed, the frequency and amplitude of some specific weather phenomena have been shown to be insufficiently reproduced, especially in summer. Here, we study one such phenomenon, namely the transient deep depressions, or extratropical cyclones, that travel across the Atlantic basin. A significant large increase of the number of these events is found in summer in the region of the North Atlantic off the western European coast. Depressions in that region are accompanied by high temperatures in continental western Europe. An ensemble of state of the art climate models are also analyzed and none of them is able to correctly reproduce the frequency of deep depressions nor their large trend, which suggests a common origin with the insufficient prediction of western European extreme heat events. Great caution should be used when analyzing climate change predictions in the region, and even more so when studying changes in complex dynamical phenomena