Scientific Publications of the University of Toulouse II Le Mirail
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Apprendre à concevoir des cartes interactives avec le logiciel en ligne uMap : Support de cours à destination notamment des personnels d’établissements publics de l’enseignement et de la recherche et des étudiants
No full textIntroduction★ TP 1 : Carte participative ★ TP 2 : Créer une première carte à partir d'une carte existante (sauvegarde complète) ★ TP 3 : Créer une carte, importer des données issues de l'open data et réaliser de la mise en forme (calque, interface) ★ TP 4 : Mettre en pratique les éléments vus au TP 3 sur d'autres données ★ TP 5 : Explorer les différents types de calque (symbologie catégorisée, cluster, heatmap, cercles proportionnels) ★ TP 6 : Améliorer la popup / Mettre à jour des données d'un calque ★ TP 7 : Gérer l'explorateur des données ★ TP 8 : Configurer un panneau latéral ★ TP 9 : Intégrer une carte uMap dans un site web via une iframe ★ TP 10 : Importer un fond de carte ancien depuis https://mapwarper.net ★ TP 11 : Convertir le format de fichier SHP en geojson via un outil en ligne pour permettre l'import dans uMapLicenceCe support de cours permet la prise en main de l'outil en ligne uMap pour cartographier des données géographiques spatialisées. En effet, uMap est un logiciel open source qui offre la possibilité de concevoir rapidement des cartes personnalisées avec des fonds OpenStreetMap (OSM) et de les intégrer facilement à un site web notamment. Plusieurs travaux pratiques sont proposés et permettent une auto-formation sur l'outil. Ce support est avant tout à destination des personnels d’établissements publics de l’enseignement et de la recherche et des étudiants.Plan des travaux pratiques :★ TP 1 : Carte participative ★ TP 2 : Créer une première carte à partir d'une carte existante (sauvegarde complète) ★ TP 3 : Créer une carte, importer des données issues de l'open data et réaliser de la mise en forme (calque, interface) ★ TP 4 : Mettre en pratique les éléments vus au TP 3 sur d'autres données ★ TP 5 : Explorer les différents types de calque (symbologie catégorisée, cluster, heatmap, cercles proportionnels) ★ TP 6 : Améliorer la popup / Mettre à jour des données d'un calque ★ TP 7 : Gérer l'explorateur des données ★ TP 8 : Configurer un panneau latéral ★ TP 9 : Intégrer une carte uMap dans un site web via une iframe ★ TP 10 : Importer un fond de carte ancien depuis https://mapwarper.net ★ TP 11 : Convertir le format de fichier SHP en geojson via un outil en ligne pour permettre l'import dans uMapPour approfondir certaines notions, voici la documentation officielle de l'outil : https://discover.umap-project.org/fr/
La reine, le faucon et l’ombre de David. Une réflexion autour d’une enluminure du Psautier de Mélisende
No full textInternational audienceLe somptueux psautier réalisé dans les années 1130 à la demande de la reine de Jérusalem Mélisende comporte une enluminure, pleine page, représentant le roi David en train de jouer de la harpe. Cette image cache un discours politique complexe, qui utilise la figure biblique pour parler du pouvoir du roi latin de Jérusalem, à mi-chemin entre une propagande politique orchestrée afin de légitimer l’autorité d’une nouvelle dynastie royale et une leçon adressée par la reine à son époux
La crémation en Corse à la lumière des récentes découvertes
No full textInternational audienceRecent excavations carried out by Inrap in Corsica have revealed a large number of structures associated to the practices of cremation, adding to an initial corpus of tombs excavated in the 1970's, prior to the development of archaeothanatological protocols. This new data has enabled us to draw up an initial summary of what we know about this practice, raising new questions about similarities or differences with other Mediterranean contexts dating from the Roman period. Indeed, funerary practices in this island context seem to reflect the socio-cultural complexity of the different groups making up a cosmopolitan society, which is also documented by other aspects of archaeology (maritime exchanges, production methods, etc.).Les récentes opérations de fouille conduites par l'Inrap en Corse ont révélé un grand nombre de structures liées à la pratique crématoire, enrichissant un corpus initial de tombes fouillées dans les années 1970, antérieurement au développement des protocoles archéothanatologiques. Ces nouvelles données ont contribué à l'élaboration d'une première synthèse des connaissances sur ce traitement du corps, soulevant notamment de nouvelles questions quant aux similarités ou particularités avec les autres contextes méditerranéens datés de la période romaine. En effet, les pratiques funéraires dans ce contexte insulaire semblent refléter la complexité socio-culturelle des différents groupes formant une société cosmopolite, documentés également par d'autres aspects en archéologie (échanges maritimes, modes de production, etc.)
Meeting of EuronanoLab at ENRIS (Bolognia) : Experts group Thin Film session: Kick off for Thin Film european group
No full textInternational audienceThe steering committee of EuronanoLab requested the implementation of the kick-off of Thin Films. Pascal Dubreuil, along with Susana de Freitas and Matias Trujillo, co-organized the session of the expert group in person with oral presentations from national networks about ALD, CVD, ALD technics and all thin film materials . A program (meeting online, workshops) for the year 2025 was then presented and validated in the session
Modeling earthquake-induced seiche processes and subsequent homogenite deposition in lacustrine settings
No full textInternational audienceEarthquakes leave distinct signatures on lake systems, including event deposits that serve as valuable paleoseismological archives. Among these deposits, homogenite layers are commonly associated with lake oscillations, i.e., seiches. Here, we investigate the seiche mechanism and the formation of a homogenite related sediment deposit within a lacustrine environment. This study focuses on the 1822 CE earthquake in the Western European Alps, which triggered subaqueous landslides in Lake Bourget (France). This event caused oscillations in the lake’s water, which subsequently resulted in the formation of a homogenite layer in the deep basin. The underlying mechanism is resolved by presenting the first comprehensive numerical model via coupling of coseismic displacement, seismic wave propagation, and mass movement with the tsunami model. The numerical simulations show excellent agreement with the available geological and historical observations. The water disturbances caused by subaqueous landslides generated small tsunami waves with a maximum runup height of approximately 2.5 m. By analyzing the tsunami signals using Fourier spectral analysis and fast iterative filtering, we determined that seismic waves are the primary drivers of seiche, which excite the natural modes of Lake Bourget. Our numerical results confirm that the sediments found in the deep basin originated from one main subaqueous landslide and from tsunami erosion of littoral sands (backwash). However, the seismically induced seiche was solely responsible for keeping the fine-grained sediment cloud in suspension for several days and led to the formation of the homogenite layer (or seiche deposit) with typical grain orientation characteristics. The proposed numerical framework could also be effective in identifying whether landslides or delta collapses (linked to homogenite/megaturbidites) in closed lakes were triggered by seismic or nonseismic sources. This distinction is crucial for reconstructing the history of past earthquakes and associated hazard
Policy Optimization via Adv2: Adversarial Learning on Advantage Functions
No full textInternational audienceWe revisit the reduction of learning in adversarial Markov decision processes [MDPs] to adversarial learning based on --values; this reduction has been considered in a number of recent articles as one building block to perform policy optimization. Namely, we first consider and extend this reduction in an ideal setting where an oracle provides value functions: it may involve any adversarial learning strategy (not just exponential weights) and it may be based indifferently on --values or on advantage functions. We then present two extensions: on the one hand, convergence of the last iterate for a vast class of adversarial learning strategies (again, not just exponential weights), satisfying a property called monotonicity of weights; on the other hand, stronger regret criteria for learning in MDPs, inherited from the stronger regret criteria of adversarial learning called strongly adaptive regret and tracking regret. Third, we demonstrate how adversarial learning, also referred to as aggregation of experts, relates to aggregation (orchestration) of expert policies: we obtain stronger forms of performance guarantees in this setting than existing ones, via yet another, simple reduction. Finally, we discuss the impact of the reduction of learning in adversarial MDPs to adversarial learning in the practical scenarios where transition kernels are unknown and value functions must be learned. In particular, we review the literature and note that many strategies for policy optimization feature a policy-improvement step based on exponential weights with estimated --values. Our main message is that this step may be replaced by the application of any adversarial learning strategy on estimated --values or on estimated advantage functions. We leave the empirical evaluation of these twists for future research
Changing coastlines and persisting links: human / littoral interactions during the Late Glacial around the Mediterranean basin
No full textInternational audienceAround the Mediterranean basin, marine resources play an important role in both subsistence and the symbolic universe. Here, we focus on the Epigravettian, a Late Glacial culture that spans the northern Mediterranean basin from Provence to the Greek coast. Epigravettian groups have a strong symbolic link with the coastal environment, reflected in their bodily ornaments composed almost exclusively of marine shells. Based on bibliographical data and unpublished data on the composition of Epigravettian ornamental assemblages, we will discuss the networks linking coastal occupations to inland sites, giving all Epigravettian groups access to marine shells. Coastal sites sometimes hold a special place in exchanges and in the chaîne opératoire for making ornaments. We will also look at how groups have adapted and modified their symbolic systems as coastlines have changed, leading to variations in species availability. In this paper, we will explore how hunter-gatherer groups maintain and sustain their ties to the coastline in the midst of Late Glacial environmental change
On the Nonconvexity of Push-Forward Constraints and Its Consequences in Machine Learning
No full textThe push-forward operation enables one to redistribute a probability measure through a deterministic map. It plays a key role in statistics and optimization: many learning problems (notably from optimal transport, generative modeling, and algorithmic fairness) include constraints or penalties framed as push-forward conditions on the model. However, the literature lacks general theoretical insights on the (non)convexity of such constraints and its consequences on the associated learning problems. This paper aims at filling this gap. In the first part, we provide a range of sufficient and necessary conditions for the (non)convexity of two sets of functions: the maps transporting one probability measure to another and the maps inducing equal output distributions across distinct probability measures. This highlights that for most probability measures, these push-forward constraints are not convex. In the second part, we show how this result implies critical limitations on the design of convex optimization problems for learning generative models or groupwise fair predictors. This work will hopefully help researchers and practitioners have a better understanding of the critical impact of push-forward conditions onto convexity
Assessment of directional scattering from Mie-resonant-plasmonic Si@Au core-shell nanoparticles
No full textInternational audienceMetamaterial research has sought to create nanostructures with strong directional optical scattering to control light propagation at the nanoscale. Core-shell architectures comprised of both resonant cores and resonant shells have been suggested as candidate particles in which the spectral overlap of the electric and magnetic dipoles can be controlled to create strong directional scattering. In this study, we present Au-decorated Si core-shell (Si@Au) particles. These were synthesized by creating Si particles through the thermal disproportionation of hydrogen silsesquioxane (HSQ), which were then decorated with ∼ 4 nm diameter Au nanoparticles. We characterized the resonant behavior of the core-shell particles using electron energy-loss spectroscopy mapping and optical single-particle scatter spectroscopy. These observations were supported by T-matrix simulations and Mie theory calculations of the scattering spectra, which show that compared to Si, Si@Au particles demonstrate a dampened magnetic dipole resonance for smaller Si core diameters (100 – 130 nm) and an enhanced magnetic dipole resonance for larger Si core sizes (150 – 200 nm). However, we show that continuous plasmonic shells of ~12 nm thickness are needed to significantly improve forward scattering intensity
Ground States of the Nonlinear Schrödinger Equation on the Tadpole Graph with a Repulsive Delta Vertex Condition
No full textWe consider the stationary nonlinear Schrödinger equation set on a tadpole graph with a repulsive delta vertex condition between the loop and the tail of the tadpole. We establish the existence of an action ground state when the size of the loop is either very small or very large. Our analysis relies on variational arguments, such as profile decomposition. When it exists, we study the shape of the ground state using ordinary differential equations arguments, such as the study of period functions. The theoretical results are completed with a numerical study