Learning Optimal Fair Scoring Systems for Multi-Class Classification

Machine Learning models are increasingly used for decision making, in particular in high-stakes applications such as credit scoring, medicine or recidivism prediction. However, there are growing concerns about these models with respect to their lack of interpretability and the undesirable biases they can generate or reproduce. While the concepts of interpretability and fairness have been extensively studied by the scientific community in recent years, few works have tackled the general multi-class classification problem under fairness constraints, and none of them proposes to generate fair and interpretable models for multi-class classification. In this paper, we use Mixed-Integer Linear Programming (MILP) techniques to produce inherently interpretable scoring systems under sparsity and fairness constraints, for the general multi-class classification setup. Our work generalizes the SLIM (Supersparse Linear Integer Models) framework that was proposed by Rudin and Ustun to learn optimal scoring systems for binary classification. The use of MILP techniques allows for an easy integration of diverse operational constraints (such as, but not restricted to, fairness or sparsity), but also for the building of certifiably optimal models (or sub-optimal models with bounded optimality gap)

Probabilistic Dataset Reconstruction from Interpretable Models

Interpretability is often pointed out as a key requirement for trustworthy machine learning. However, learning and releasing models that are inherently interpretable leaks information regarding the underlying training data. As such disclosure may directly conflict with privacy, a precise quantification of the privacy impact of such breach is a fundamental problem. For instance, previous work have shown that the structure of a decision tree can be leveraged to build a probabilistic reconstruction of its training dataset, with the uncertainty of the reconstruction being a relevant metric for the information leak. In this paper, we propose of a novel framework generalizing these probabilistic reconstructions in the sense that it can handle other forms of interpretable models and more generic types of knowledge. In addition, we demonstrate that under realistic assumptions regarding the interpretable models' structure, the uncertainty of the reconstruction can be computed efficiently. Finally, we illustrate the applicability of our approach on both decision trees and rule lists, by comparing the theoretical information leak associated to either exact or heuristic learning algorithms. Our results suggest that optimal interpretable models are often more compact and leak less information regarding their training data than greedily-built ones, for a given accuracy level

Analyse multi-échelles du flambage des matériaux hétérogènes

International audienceDans ce travail, une technique numérique efficace est proposée pour analyser les instabilités dans le cadre des matériaux hétérogènes où les flambages peuvent survenir au niveau macroscopique ainsi qu'au niveau microscopique. La technique proposée combine la méthode des éléments finis multi-niveaux (EF 2) et la méthode asymptotique numérique (MAN). Nous nous limitons aux matériaux élastiques, par contre, la non-linéarité géométrique est prise en compte aux niveaux microscopique et macroscopique

Nouvelles approches basées sur la réduction de modèle pour le calcul multi-échelles des matériaux hyperélastiques en grandes déformations

Dans cette étude, nous présentons une méthode multi-échelle pour l'homogénéisation des matériaux hétérogènes, hyperélastiques, en grandes déformations. Une méthode d'éléments finis multi niveaux est utilisée en tandem avec une méthode de réduction de modèle de type POD pour alléger les coûts liés aux nombreux problèmes non linéaires qu'il est nécessaire de résoudre aux points de Gauss. Une extension de cette technique en vue de traiter les instabilités au niveau microscopique est proposée, par le biais d'une technique de perturbation avec continuation. Dans les différentes approches, chaque problème non linéaire associé à l'échelle microscopique est remplacé par un problème de petite taille (quelques dizaines de degrés de liberté). Des gains significatifs en temps de calculs liés à l'assemblage et la décomposition des matrices tangentes sont obtenus, ainsi qu'un gain de place mémoire lié à la réduction de la taille de la base décrivant l'histoire des différentes domaines micro

Gonad-related factors promote muscle performance gain during postnatal development in male and female mice

To better define the role of male and female gonad-related factors (MGRF, presumably testosterone, and FGRF, presumably estradiol, respectively) on mouse hindlimb skeletal muscle contractile performance/function gain during postnatal development, we analyzed the effect of castration initiated before puberty in male and female mice. We found that muscle absolute and specific (normalized to muscle weight) maximal forces were decreased in 6-mo-old male and female castrated mice compared with age- and sex-matched intact mice, without alteration in neuromuscular transmission. Moreover, castration decreased absolute and specific maximal powers, another important aspect of muscle performance, in 6-mo-old males, but not in females. Absolute maximal force was similarly reduced by castration in 3-mo-old muscle fiber androgen receptor (AR)-deficient and wild-type male mice, indicating that the effect of MGRF was muscle fiber AR independent. Castration reduced the muscle weight gain in 3-mo mice of both sexes and in 6-mo females but not in males. We also found that bone morphogenetic protein signaling through Smad1/5/9 was not altered by castration in atrophic muscle of 3-mo-old mice of both sexes. Moreover, castration decreased the sexual dimorphism regarding muscle performance. Together, these results demonstrated that in the long term, MGRF and FGRF promote muscle performance gain in mice during postnatal development, independently of muscle growth in males, largely via improving muscle contractile quality (force and power normalized), and that MGFR and FGRF also contribute to sexual dimorphism. However, the mechanisms underlying MGFR and FGRF actions remain to be determined

Coherent oscillations of electrons in tunnel-coupled wells under ultrafast intersubband excitation

Ultrafast intersubband excitation of electrons in tunnell-coupled wells is studied depending on the structure parameters, the duration of the infrared pump and the detuning frequency. The temporal dependencies of the photoinduced concentration and dipole moment are obtained for two cases of transitions: from the single ground state to the tunnel-coupled excited states and from the tunnel-coupled states to the single excited state. The peculiarities of dephasing and population relaxation processes are also taken into account. The nonlinear regime of the response is also considered when the splitting energy between the tunnel-coupled levels is renormalized by the photoexcited electron concentration. The dependencies of the period and the amplitude of oscillations on the excitation pulse are presented with a description of the nonlinear oscillations damping.Comment: 8 pages, 12 figure

Yap1-Driven Intestinal Repair Is Controlled by Group 3 Innate Lymphoid Cells

Intestinal repair is driven by epithelial stem cells, but how these stem cells are instructed to initiate repair was unknown. Here, Romera-Hernández et al. report that epithelial proliferation after damage is independent of the stem cell-protective signal IL-22 but requires ILC3-dependent amplification of regenerative YAP1 signaling in stem cells.Tissue repair requires temporal control of progenitor cell proliferation and differentiation to replenish damaged cells. In response to acute insult, group 3 innate lymphoid cells (ILC3s) regulate intestinal stem cell maintenance and subsequent tissue repair. ILC3-derived IL-22 is important for stem cell protection, but the mechanisms of ILC3-driven tissue regeneration remain incompletely defined. Here we report that ILC3-driven epithelial proliferation and tissue regeneration are independent of IL-22. In contrast, ILC3s amplify the magnitude of Hippo-Yap1 signaling in intestinal crypt cells, ensuring adequate initiation of tissue repair and preventing excessive pathology. Mechanistically, ILC3-driven tissue repair is Stat3 indepe

Les avancées de la recherche dans le domaine de la modélisation des interactions sol-arbre

Les outils de modélisation au service de la politique, de la planification et de la gestion forestière ne permettent pas encore une évaluation simultanée de l’impact des changements globaux et de la gestion sur les différentes fonctions écologiques et productives assurées par les écosystèmes forestiers. Nous proposons un état des lieux des modèles disponibles dans les différentes disciplines que sont la dendrométrie, l’écophysiologie et les sciences du sol et comment l’intégration des concepts de ces trois disciplines peut permettre d’élaborer les outils nécessaires au gestionnaire. In fine, ces nouveaux outils devront être suffisamment complets pour répondre à des questions à l’échelle de l’écosystème ; distinguer ce qui relève du processus générique de ce qui reste site-dépendant ; permettre de définir puis simuler des scénarios de gestion variés et innovants en environnement incertain, avec des contraintes de plus en plus fortes ; et être documentés et référencés pour garantir leur pérennité et leur utilisation

Awakening the control of the ankle dorsiflexors in the post-stroke hemiplegic subject to improve walking activity and social participation: the WAKE (Walking Ankle isoKinetic Exercise) randomised, controlled trial

Stroke is the leading cause of acquired disability in France. While 90% of patients recover the ability to walk, it is often limited with a steady speed of approximately 0.7 m/s. This limitation of walking activity is partly related to a decrease in strength associated with more or less significant spasticity. In particular, it seems that the strength of the dorsiflexor muscles is directly related to walking speed. We hypothesise that a protocol based on gestural repetition targeted at the ankle during the subacute phase potentiates the recovery of motor control, improving walking activity, and participates in recovering better social participation

CETOBaC - Centre d’études turques, ottomanes, balkaniques et centrasiatiques

Marc Aymes, chargé de recherche au CNRSBenjamin Gourisse, ATER à l’Université Paris-I/Panthéon-SorbonneEmmanuel Szurek, doctorant à l’EHESS Sociologie historique de l’État en Turquie depuis les Tanzimat Le séminaire s’est poursuivi en 2010-2011 pour sa troisième année consécutive. Il demeure articulé au programme ANR TRANSTUR, « Ordonner et transiger. Modalités de gouvernement et d’administration en Turquie et dans l’Empire ottoman du XIXe siècle à nos jours » (2008-2011), dont il permet de d..