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Peut-on vraiment co-construire sa recherche ? Enjeux de la recherche autour de population marginalisée à partir de la projection de Visibles
No full textInternational audienc
Social security and retirement around the world: lessons from a long-term collaboration
No full textInternational audienceDeclining labor force participation of older men throughout the 20th century and recent increases in participation have generated substantial interest in understanding the effect of public pensions on retirement. The National Bureau of Economic Research's International Social Security (ISS) Project, a long-term collaboration among researchers in a dozen developed countries, has explored this and related questions. The project employs a harmonized approach to conduct within-country analyses that are combined for meaningful cross-country comparisons. The key lesson is that the choices of policy makers affect the incentive to work at older ages and these incentives have important effects on retirement behavior
Performativités, domestications et résistances mémétiques
No full textInternational audienceThe Hybrid issue, dedicated to memes, that you are reading is the sequel to an earlier issue titled Birth and Rebirth of Memes. The lives and vitality of memes published in November 2024. That issue focused on defining memes and their perimeters, the diverse forms of memetic life that populate our communicational spaces, as well as the processes of meme creation. In this second volume, we want to bring the communicational object that is the meme into the arena of reception, to carefully observe from that vantage point how meme representations, social lives, and the practices associated with memes evolve.Le numéro d’Hybrid dédié aux mèmes que vous avez sous les yeux fait suite à un premier volume intitulé Naissance et renaissance des mèmes. Vies et vitalités des mèmes paru en novembre 2024. Celui-ci se concentrait sur la définition des mèmes, leurs périmètres, les diverses formes de vie mémétiques qui peuplent nos espaces communicationnels, ainsi que sur leurs processus de création. Dans ce second volume, nous avons souhaité faire entrer cet objet communicationnel sur la scène de la réception. Nous y observons de plus près les évolutions de leurs représentations, leurs vies sociales et les pratiques qui leur sont associées
Spartacus: A review and aggregation of reference datasets reporting the normal shoulder girdle kinematics during uniplanar humerus motions
No full textInternational audienceUnderstanding 3D shoulder girdle kinematics is essential for applications in medicine, sports, and computational biomechanics, where reference data help quantify deviations from the standard. Unfortunately, existing datasets on shoulder kinematics based on gold-standard measurements are often inconsistent in data collection methods, segment definitions, and joint kinematics computation, limiting their relevance. This study reviews and aggregates available datasets to establish Spartacus, a comprehensive reference for normal shoulder girdle kinematics. We gathered 20 datasets, published between 2000 and 2023, and aligned them, when possible, with the International Society of Biomechanics recommendations to enable population-wide analysis. Spartacus comprises data recorded in vivo (70 %) or ex vivo (30 %) on 245 shoulders using intracortical pins (55 %) or imaging (45 %), primarily during active dynamic (65 %) movements. The dataset predominantly covers arm elevation records in the scapular (70 %), frontal (50 %), and sagittal (50 %) planes, but also includes internal-external rotation and horizontal flexion. Both rotations and translations are represented across all shoulder girdle joints, with scapulothoracic rotations being the most frequent (75 %). Our approach corrects or at least compensates for six identified deviations in local coordinate system definitions and joint kinematics computation methods. Substantial inconsistencies across existing datasets reveal a need for improved standardisation to facilitate reliable data comparisons. Spartacus, openly available, will enable researchers to explor
A benchmarking methodology to assess population synthesis algorithms: A case study for Ile-de-France (France)
No full textInternational audienceIn transportation research, population synthesis is a critical part of agent-based microsimulations. In the vast existing literature, only a few works consider developing a framework for analyzing population synthesis algorithms from a quality perspective. In this paper, we develop a framework for the analysis of population synthesis trajectories and perform a comparative analysis of four population synthesis algorithms, focusing on their behavior in case of incomplete training data.We show that while some tend to generate attribute combinations that are sampling zeros, others have an almost equal tendency to generate attribute combinations that are sampling or structural zeros
Intertwined renewable and digital transitions: a study on South Australia’s hybridized electricity system
No full textInternational audienceThis paper examines the implications of an energy transition characterized by the widespread adoption of renewable energy sources, distributed energy assets, and digitalization, using South Australia as a central case study. By leveraging and adapting the concept of “Electrical Hybridization” (Verdeil and Jaglin, 2023), we show how South Australia’s ambitious energy policies, which integrate economic growth with decarbonization, are transforming its electricity system. This transformation requires both the reinforcement of the electricity network (reticulation) and the extensive deployment of distributed energy assets (heterogeneity). An additional trend, coordination, is emerging as a crucial element in South Australia, facilitating the control of distributed energy assets through smart interfaces and digital networks. We then analyse the system-wide evolutions driven by the convergence of renewable energy transition and digitalization, detailing the evolving energy governance arrangements and underlining the significant interaction between public bodies and private initiatives in investments and regulatory reforms. Finally, we explore the broader implications of these developments, raising critical questions around decentralization, local empowerment, and participation in the energy transition. We conclude by suggesting that further research is essential to fully understand the complex, intertwined effects of the renewable and digital transitions
Potentially useful probabilistic approaches to uncertainty quantification and statistical surrogate models for metamaterials design
No full textInternational audienceThree aspects will be concerning uncertainty quantification and probabilistic learning [1]. First, as a parametric probabilistic approach to uncertainties, a random field theory with symmetry classes will be presented for modeling heterogeneous elastic media [2,3], with an illustration devoted to stochastic continuum modeling of random interphases derived from atomistic simulations of a polymer nanocomposite, coupled with a statistical inverse problem [4]. Second, as a nonparametric probabilistic approach to uncertainties induced by model-form errors, a nonlinear random operator construction [5] will be presented, with an illustration devoted to the nonlinear dynamics of a micro accelerometer. Finally, the construction of statistical surrogate models for uncertain systems will be addressed using probabilistic learning on manifolds for cases involving small training datasets [6,7], with an illustration focused on concurrent meso-to-macro scale modeling of nonlinear random materials without scale separation [8].[1] C. Soize, An overview on uncertainty quantification and probabilistic learning on manifolds in multiscale mechanics of materials, Mathematics and Mechanics of Complex Systems, 11(1), 87-174 (2023).[2] C. Soize, Non Gaussian positive-definite matrix-valued random fields for elliptic stochastic partial differential operators, Comput. Methods Appl. Mech. Eng., 195(1-3), 26-64 (2006).[3] J. Guilleminot, C. Soize, Stochastic model and generator for random fields with symmetry properties: application to the mesoscopic modeling of elastic random media, Multiscale Modeling and Simulation (A SIAM Interdisciplinary Journal), 11(3), 840-870 (2013). [4] T.T. Le, J. Guilleminot, C. Soize, Stochastic continuum modeling of random interphases from atomistic simulations. Application to a polymer nanocomposite, Comput. Methods Appl. Mech. Eng., 303, 430-449 (2016)[5] C. Soize, C. Farhat, A nonparametric probabilistic approach for quantifying uncertainties in low- and high-dimensional nonlinear models, Int. J. Numer. Methods Eng., 109(6), 837-888 (2017).[6] C. Soize, R. Ghanem, Data-driven probability concentration and sampling on manifold, Journal of Computational Physics, 321, 242-258 (2016).[7] C. Soize, R. Ghanem, Probabilistic-learning-based stochastic surrogate model from small incomplete datasets for nonlinear dynamical systems, Comput. Methods Appl. Mech. Eng., 418, 116498, (2024).[8] P. Chen, J. Guilleminot, C. Soize, Concurrent multiscale simulations of nonlinear random materials using probabilistic learning, Comput. Methods Appl. Mech. Eng., 422, 116837 (2024)
Robust topology optimization accounting for uncertain microstructural changes
No full textInternational audienc
PeGazUs : une méthode de reconstitution de l'évolution des entités géographiques à partir de données hétérogènes et fragmentaires
No full textNational audienceConstituer un référentiel géo-historique d'entités spatiales permet de nombreux cas d'application, comme l'étude des dynamiques urbaines. Différentes approches dans la littérature montrent qu'il est possible de construire un tel référentiel, mais imposent d'avoir des jeux de données homogènes et structurés, à différentes dates. La disponibilité croissante des sources d'archives numérisées et les progrès des méthodes d'extraction d'informations dans ces sources permettent désormais de produire de grands volumes de données hétérogènes, fragmentaires et incomplètes, sur les entités géographiques du passé et leurs évolutions. Or, les approches de création de référentiels géohistoriques existantes ne permettent pas encore d'intégrer ces types de données de façon satisfaisante. Dans cet article, nous proposons une méthode de reconstitution de l'évolution spatio-temporelle des entités géographiques à partir de données hétérogènes et fragmentaires provenant de différentes sources. Nous expliquons aussi la manière dont on vérifie la cohérence du graphe de données créé à partir de cette méthode. Enfin, nous mettons cette dernière en application sur le quartier de la Butte aux Cailles à Paris à partir de sources de la fin du XVIII e siècle à nos jours
