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Combinatorics of rectangulations: old and new bijections
No full textInternational audienceA rectangulation is a decomposition of a rectangle into finitely many rectangles. Via natural equivalence relations, rectangulations can be seen as combinatorial objects with a rich structure, with links to lattice congruences, flip graphs, polytopes, lattice paths, Hopf algebras, etc. In this paper, we first revisit the structure of the respective equivalence classes: weak rectangulations that preserve rectangle-segment adjacencies, and strong rectangulations that preserve rectangle-rectangle adjacencies. We thoroughly investigate posets defined by adjacency in rectangulations of both kinds, and unify and simplify known bijections between rectangulations and permutation classes. This yields a uniform treatment of mappings between permutations and rectangulations that unifies the results from earlier contributions, and emphasizes parallels and differences between the weak and the strong cases. Then, we consider guillotine rectangulations, and prove that they can be characterized -- under all known mappings between permutations and rectangulations -- by avoidance of two mesh patterns that correspond to windmills in rectangulations. This yields new permutation classes in bijection with weak guillotine rectangulations, and the first known permutation class in bijection with strong guillotine rectangulations. Finally, we address enumerative issues and prove asymptotic bounds for several families of strong rectangulations
Class conditional conformal prediction for multiple inputs by p-value aggregation
No full textInternational audienceConformal prediction methods are statistical tools designed to quantify uncertainty and generate predictive sets with guaranteed coverage probabilities. This work introduces an innovative refinement to these methods for classification tasks, specifically tailored for scenarios where multiple observations (multi-inputs) of a single instance are available at prediction time. Our approach is particularly motivated by applications in citizen science, where multiple images of the same plant or animal are captured by individuals. Our method integrates the information from each observation into conformal prediction, enabling a reduction in the size of the predicted label set while preserving the required class-conditional coverage guarantee. The approach is based on the aggregation of conformal p-values computed from each observation of a multi-input. By exploiting the exact distribution of these p-values, we propose a general aggregation framework using an abstract scoring function, encompassing many classical statistical tools. Knowledge of this distribution also enables refined versions of standard strategies, such as majority voting. We evaluate our method on simulated and real data, with a particular focus on Pl@ntNet, a prominent citizen science platform that facilitates the collection and identification of plant species through user-submitted images
Analyses expérimentales et numériques du comportement des couches de surface des chaussées bitumineuses sous trafic
No full textInternational audienceLa majorité des études de comportement des chaussées bitumineuses se concentre sur les couches de base, en raison de leur contribution majeure à la résistance à la fatigue. Cependant, peu de travaux se sont intéressés au comportement des couches de surface. Cette étude évalue la réponse des couches de surface avec le trafic, sous différentes conditions de température et différentes configurations d'essieux, en utilisant des approches expérimentales et numériques. Une structure de chaussée en vraie grandeur a été testée. Des jauges de déformation ainsi que des fibres optiques placées à différentes profondeurs, sont utilisées pour analyser les déformations. Les résultats montrent des variations significatives des déformations avec le trafic et la température, notamment à la base de la couche de surface. À haute température, un décollement partiel de l'interface entre la couche de surface et la couche de base a été observé sous l'effet des charges. Ce phénomène a entraîné des déformations en extension à la base de la couche de surface. Les simulations numériques réalisées avec le logiciel Viscoroute©2.0 permettent de prédire les déformations mesurées, en tenant compte d'une interface partiellement décollée, ainsi que l'effet des charges dues aux essieux simples et tridem. L'ensemble de l'étude a permis de mieux comprendre le fonctionnement des couches de surface, sous différentes conditions de sollicitations
La diplomatie numérique de la Chine en Italie : vers une défense « amicale » du récit dominant de Pékin sur la coopération sino-italienne
No full textInternational audienceÀ partir d’une analyse fine de l’approche chinoise de la diplomatie publique et de ses postures politiques, le présent article examine les tactiques de communication déployées par Pékin en Italie durant le mois suivant l’éclosion du conflit de la Russie en Ukraine (24 février-23 mars 2022). Contrairement à la démarche offensante et incisive adoptée par les diplomates chinois en France, l’attitude des représentants officiels chinois en Italie se caractérise par sa modération et sa finesse. Cette attitude traduit une stratégie délibérée de communication diplomatique de la part de Pékin, visant à consolider l’empreinte de ses orientations politiques et de ses intérêts économiques en Italie, un carrefour géopolitique crucial pour l’implémentation de son projet de la nouvelle Route de la soie dans le G7
IDENTIFICATION OF THE LATERAL TRACK IRREGULARITIES FROM THE BEHAVIOR OF THE TRAIN’S AXLES ON A SURROGATE RAILWAY DYNAMICS MODEL
No full textInternational audienceThis work aims at the reverse identification of the lateral offset irregularity from the kinematics of the axle on a simplified train surrogate model. The fundamental goal of this study is to have a better understanding of the dynamics of the train which would ultimately allow to identify the track irregularities from axle-boxes acceleration measurements on commercial trains. First, a known surrogate model of the dynamics of the axle from the literature is adapted to include a train carbody and the railway track irregularities and then the inversion of the system is achieved so that a relationship between the kinematics that would be measured on the axle and the lateral track irregularity is established
: “Play in real life”: Enrolling professionals to better engage students in learning business skills
No full textInternational audienceComment introduire des mises en situations les plus réalistes possibles dans le cadre d’un enseignement universitaire dans les murs ? Comment enrôler des professionnels dans l’évaluation de la montée en compétences commerciales des étudiants ? L’article qui suit décrit une innovation pédagogique s’appuyant sur une gamification et une communication régulière d’un projet d’études auprès de professionnels. Il propose un cadre théorique pour évaluer ce dispositif. La valorisation par les étudiants des compétences commerciales acquises est un enjeu fort de la dernière année de licence, en amont d’un stage et/ou d’un apprentissage. Mais ce marketing de soi suppose qu’ils se sentent légitimes à revendiquer des compétences professionnelles, surtout quand ils ne disposent pas d’expériences professionnelles antérieures y afférent. L’analyse des effets de l’innovation décrite a souligné que la participation de professionnels à un projet pédagogique leur permettant d’être témoin de la progression des étudiants est un levier pour améliorer leur légitimité perçue. Nous montrons que la théorie de l’engagement est un cadre pertinent pour évaluer les effets de cette innovation sur les étudiants. Ce faisant, nous explorons la possibilité d’évaluer, a posteriori, une innovation ordinaire (Alter, 2010)
Is 3D load-balancing more relevant than 2D for estimating medial and lateral knee contact forces?
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Special Issue on urban logistics facilities: sustainability impacts, real estate, and urban planning in Transportation Planning and Technology
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Informal Caregiving Within the Household and Family
No full textInternational audienceAccording to the World Health Organization, 16% of the world’s population experienced a disability in 2021. This is expected to rise against a background of global demographic aging and growing support needs, often provided by relatives. This chapter reviews evidence on informal care to a relative. First, it provides stylized facts on the characteristics of caregivers and how the use of informal care varies across countries. Second, it discusses the decision-making process of caregiving, with a focus on parental care and the role of siblings. Third, it surveys the evidence on the implications of providing care for informal caregivers on their labor market outcomes, their health and well-being, and their social and family life. Results are presented according to the nature of the care relationship. While the effect of caring for a parent on wages or the extensive margin of work is unclear, women’s working hours are negatively affected. Caregivers to a parent also experience negative effects on their physical health. Having a spouse in poor health has generally either a negative effect or no effect on the labor supply. While a spousal health shock leads to adverse effects on mental health, especially for women, physical health seems to be spared. It is also associated with an increased risk of marital dissatisfaction and potential subsequent separation. Caring for a child has adverse effects on the parents’ labor outcomes and on their mental health. Mothers appear to be more affected than fathers. Parents of a disabled child also have a lower probability of remaining together, while the effect on fertility is ambiguous. A child’s disability has long-term effects on their siblings too, affecting their educational outcomes, mental health, and future earnings