HAL Portal de Univ. Gustave Eiffel
Not a member yet
72847 research outputs found
Sort by
Creators' Commenting Behavior and Linking Strategies in the French YouTube Environment
No full textFrom an empirical analysis of a rich dataset describing the French YouTube environment, this article attempts to understand the determinants of revenue on the YouTube platform. While the revenues depend on the level of popularity of Youtubers, our focus lies in discerning the factors driving popularity. Specifically, this research focuses on understanding to what degree commenting videos on YouTube can serve as a strategic tool for the commentators. We first distinguish between different commenting strategies, depending on whether the commentator is a YouTuber or an ordinary viewer. Subsequently, we employ an Exponential Random Graph Model (ERGM) to assess the factors influencing the likelihood of commenting on a video. Our findings underscore the significance of co-commenting networks on the YouTube platform, suggesting that cooperation may emerge as a prevailing strategy on YouTube
25 Additional Problems -- Extension to the Book "125 Problems in Text Algorithms"
No full textThis very preliminary text is related to ``Algorithms on Texts'', also called ``Algorithmic Stringology''. It is an extension of the book ``125 Problems in Text Algorithms'' providing, in the same compact style, more problems with solutions. We refer also to the companions to ``Text algorithms'' available at http://monge.univ-mlv.fr/~mac/CLR/clr1-20.pdf and at the web page http://125-problems.univ-mlv.fr, where all 150 problems (including the ones presented here) are briefly announced. The selected problems satisfy three criteria: challenging, having short tricky solutions and solvable with only very basic background in stringology. For the basics in stringology we refer to http://monge.univ-mlv.fr/~mac/CLR/clr1-20.pdf
Agricultures machiniques: Représentation du travail agricole mécanisé sur YouTube
No full textNational audienceAgricultures machiniquesReprésentation du travail agricole mécanisé sur YouTube
Une crise agricole mais quelle crise?
No full textInternational audienceThe article analyzes agricultural crises, highlighting their specific nature: beyond classic economic mechanisms, they directly affect food security and sovereignty, often triggering social and political tensions. Their causes include climate shocks, animal and plant diseases, global price fluctuations, rising input costs, and structural issues such as rural exodus, aging farmers, and soil degradation.Historically, agricultural crises have alternated between overproduction (price collapse, bankruptcies, waste) and underproduction (famine, malnutrition). Industrialization and mechanization boosted productivity but also increased dependence on capital and global markets, leaving many producers vulnerable.The current crisis (2023–2024) is part of a broader European wave of farmers’ mobilizations. Their demands concern low incomes, heavy taxation, unfair competition, the burden of environmental regulations, and a call for recognition. This crisis is as much moral and cultural as economic, reflecting the end of the post-war productivist model.Price support policies, such as the CAP’s guaranteed prices, once secured farmers’ income and boosted production, but led to costly and environmentally damaging overproduction. Today, the proposal of minimum prices re-emerges, but raises concerns about competitiveness, consumer costs, and perverse effects. Alternative solutions include targeted subsidies, quality-based regulation, and support for agroecological transition.In conclusion, today’s agricultural crisis is systemic—economic, climatic, social, and cultural. It signals the end of a cycle and an opportunity to reinvent a sustainable agricultural model that reconciles food security, social justice, and ecological transition.L’article analyse les crises agricoles en soulignant leur spécificité : au-delà des mécanismes économiques classiques, elles touchent à la sécurité et à la souveraineté alimentaires, pouvant provoquer des tensions sociales et politiques. Elles résultent d’aléas climatiques, de maladies, de fluctuations des prix mondiaux, de la hausse des intrants ou de difficultés structurelles (exode rural, vieillissement, dégradation des sols).Historiquement, les crises agricoles alternent entre surproduction (chute des prix, faillites, gaspillage) et sous-production (famine, malnutrition). L’industrialisation et la mécanisation ont accru la productivité mais aussi la dépendance au capital et aux marchés mondiaux, fragilisant de nombreux producteurs.La crise actuelle (2023-2024) s’inscrit dans un contexte européen marqué par des mobilisations d’agriculteurs. Leurs revendications portent sur la faiblesse des revenus, le poids fiscal, la concurrence jugée déloyale, l’empilement des normes environnementales et un besoin de reconnaissance. La crise est autant économique que morale et culturelle, traduisant la fin d’un modèle productiviste hérité d’après-guerre.Les politiques de soutien aux prix, comme les prix garantis de la PAC, ont permis dans le passé de sécuriser les revenus et d’augmenter la production, mais au prix d’une surproduction coûteuse et écologiquement néfaste. Aujourd’hui, l’idée de prix planchers réapparaît, mais suscite de vifs débats sur la compétitivité, l’impact sur les consommateurs et les risques d’effets pervers. Des solutions alternatives sont envisagées : subventions ciblées, régulation par la qualité et accompagnement de la transition agroécologique.En conclusion, la crise agricole actuelle est systémique – économique, climatique, sociale et culturelle. Elle marque la fin d’un cycle et ouvre une opportunité pour réinventer un modèle agricole durable, conciliant sécurité alimentaire, justice sociale et transition écologique
Death, Retirement, or Redeployment for Unproductive Farm Animals? Dispositional Tensions in Organizational Routines
No full textInternational audienceHuman–animal relationships, including ethic of care relationships, are of growing interest to organization studies, reflecting the substantial role of animals in organizing processes. While some scholars approach these as working relationships, few studies examine the organizational routines established to manage animals in the period after they have been retired due to age, illness, or lack of productiveness. Through a multiple case study of four contrasting sectors in France (dairy ewes, horses, experimental animals, hens), we take a Foucauldian theoretical standpoint, based on the concept of ‘Dispositif,’ to map and analyze the different patterns and dynamics of this organizational routine. Our results indicate that ‘death’ organizational patterns are the most common, with animals other than horses typically being killed immediately upon retirement. However, operators often attempt to implement work-around organizational patterns to ‘save’ animals and ensure them a decent retirement. We explore the numerous and complex interactions between heterogeneous elements that form the different patterns of the routine (actors, instruments, discourses, values, places, machines, etc.), to explain how the routine is both a driver and a result of ‘ethical blindness’ or ‘ethical foresight’ in the management of culled animals. We then interpret the dynamic of the routine as a complex interplay between three major dispositives that govern our relationships with animals. Unfolding and understanding this interplay is useful for progressively acting on various levers (such as artifacts of the routine) and for collectively endeavoring toward a long-term commitment to ethical foresight
Une décennie de marchés fonciers pour les organismes de logement social franciliens
No full textBasé sur l'exploitation des données foncières DV3F, ce panorama statistique décrit la place des organismes de logement social (OLS) dans les marchés fonciers et immobiliers franciliens au cours de la décennie 2010. L'analyse permet de faire ressortir plusieurs tendances de fond.La première tendance renvoie au report progressif des marchés fonciers vers les marchés immobiliers, les OLS acquérant davantage des logements à d’autres acteurs plutôt que des parcelles pour les produire. Cette tendance de fond s’accompagne d’une modification dans la nature des fonciers acquis pour produire du logement social. On assiste d'une part au repositionnement des acquisitions foncières en grande couronne (au détriment de la petite couronne et de Paris). On assiste également sur la décennie 2010 à un tarissement de la filière des fonciers publics au profit de fonciers cédés par des aménageurs privés, promoteurs et personnes physiques. Les OLS se confrontent ainsi plus directement à des formes de concurrence foncière et à des logiques marchandes de valorisation des parcelles
Airport Traffic Simulator for Anti-icing Runway Winter Products: Chemical Performance by Mechanical Activation
No full textInternational audienceThe chemicals products used in airports are essential to keep air traffic flowing safely and smoothly during winter time. However, there is limited reliable information available regarding both their performance and optimal use. It is therefore essential to properly characterize these products and to define their optimum application rates according to the various precipitation parameters (type, intensity, temperature) and other meteorological ones (wind strength, humidity level, etc.), either current and those to come. The mechanical contribution of traffic is often cited as a significant contribution on their efficiency.Mechanical activation plays a critical role in the effectiveness of Runway De-icing Product (RDP) as an anti-icing agent. For instance, if a spreader provides consistent mechanical activation of the product, this can enable airports to avoid spreading again RDP and reducing the risk of runway saturation, saving money and extending the product's effective time. Thus, the development of an Airport Traffic Simulator (ATS) was undertaken to replicate real-world airport runway conditions and their surrounding environment within a laboratory setting. The evaluation of anti-icing efficiency provides airport maintenance teams with tools to optimize product application costs while maintaining maximum safety. The failure of these tests is determined by the exothermal reaction caused by the ice formation on the circulated surface, which is identified using a thermal camera. The product's efficiency time increases as the temperature rises and the precipitation intensity decreases. This relationship underscores the importance of considering weather conditions when determining the optimal application strategy for RDP. In addition, the ATS crushing of surface contaminant of a RDP has demonstrated that a more frequent mechanical activation significantly enhances the product efficiency as an anti-icing agent. The results obtained in this project serve as a thiving basis for developing a broader analytical framework, thanks to the robust methodology employed, which can be extended to other weather conditions.</p
La pertinence des politiques locales sur le e-commerce et ses mobilités
No full textInternational audienc
La contractualisation financière entre l’État et les collectivités locales : la controverse des deux dépenses publique
No full textInternational audienceFollowing the scholarship on austeritarian public finances, this article focuses on one of the latest instruments governing fiscal and financial relations between the State and local authorities in France, called the “Cahors contracts”. This tool, introduced in 2017 (and then suspended at the start of the pandemic in 2020), aims to limit the growth of operating expenditures through a contract signed between the State and some local authorities. While tracing the conception of this instrument within the central government and its negotiation with—and contestation by—local government associations, the article produces two main findings. First, it highlights the concrete ways in which a budget consolidation order is implemented and maintained across different levels of government, from the European Union to local authorities and central administrations. Second, it underlines how the controversies surrounding the instrument—its binding and a-territorial nature, the type of targeted expenditures—stem from the gap between two different conventions of public spending, opposing the State as guarantor of the consolidation order and local authoritiesDans la lignée des travaux sur l'austérité dans les finances publiques, cet article porte sur l'un des derniers instruments organisant les relations fiscalo-financières entre l'État et les collectivités locales en France : la contractualisation financière. Ce dispositif introduit en 2017 (puis suspendu au début de la pandémie en 2020) vise à limiter la progression des dépenses de fonctionnement par un contrat signé entre l'État et certaines collectivités. En retraçant l'élaboration de cet instrument au sein de l'État central et dans ses relations avec les associations de collectivités locales, l'article produit deux résultats principaux. Il contribue d'abord à mettre en évidence les modalités concrètes par lesquelles un ordre de consolidation budgétaire se déploie et se maintient entre différentes échelles d'action publique, de l'Union Européenne aux collectivités en passant par les administrations centrales. Il montre ensuite que les controverses autour du caractère contraignant et a-territorialisé de cet instrument et de la nature des dépenses contractualisées résultent du décalage entre deux conventions différentes de la dépense publique, opposant l'État garant de l'ordre de consolidation et les collectivités locales
Differentiable Constitutive Modeling with FEniCSx and JAX
No full textInternational audienceThe field of computational mechanics is increasingly converging with machine learning, particularly in the area of constitutive modeling. Constitutive models, which are inherently data-driven, share formal similarities with neural network layers. Beyond simply learning constitutive models from data, there is significant potential in developing implementations of traditional constitutive models that are compatible with machine learning frameworks.Automatic differentiation (AD) has transformed machine learning by enabling complex computations to be composed from simpler operations while automating the calculation of derivatives. In this talk, we will explore the application of AD to constitutive modeling, with a special emphasis on two key areas: efficient tangent operator computation and material parameter sensitivity. These developments are now part of the dolfinx_materials package which leverages implementations in JAX.First, AD can be used to automatically derive consistent tangent operators, which are essential for the efficient integration of constitutive models in large-scale simulations. We will discuss various strategies for obtaining these operators, including applying AD directly to the unrolled algorithm or using the more efficient method of implicit differentiation.Second, AD can also be leveraged to compute sensitivities of material parameters, enabling more efficient model calibration. Finally, we will explore how AD and implicit differentiation can be extended to handle more complex constitutive models, such as multi-surface plasticity, which require advanced nonlinear solvers