Paris Dauphine University

About: Paris Dauphine University is a education organization based out in Paris, France. It is known for research contribution in the topics: Population & Approximation algorithm. The organization has 1766 authors who have published 6909 publications receiving 162747 citations. The organization is also known as: Paris Dauphine & Dauphine.

One-dimensional Gagliardo–Nirenberg–Sobolev inequalities: remarks on duality and flows

Abstract: This paper is devoted to one-dimensional interpolation Gagliardo-Nirenberg-Sobolev inequalities. We study how various notions of duality, transport and monotonicity of functionals along flows defined by some nonlinear diffusion equations apply. We start by reducing the inequality to a much simpler dual variational problem using mass transportation theory. Our second main result is devoted to the construction of a Lyapunov functional associated with a nonlinear diffusion equation, that provides an alternative proof of the inequality. The key observation is that the inequality on the line is equivalent to Sobolev's inequality on the sphere, at least when the dimension is an integer, or to the critical interpolation inequality for the ultraspherical operator in the general case. The time derivative of the functional along the flow is itself very interesting. It explains the machinery of some rigidity estimates for nonlinear elliptic equations and shows how eigenvalues of a linearized problem enter in the computations. Notions of gradient flows are then discussed for various notions of distances. Throughout this paper we shall deal with two classes of inequalities corresponding either to p>2 or to p<2. The algebraic part in the computations is very similar in both cases, although the case p<2 is definitely less standard.

Inégalités de recours aux soins en Europe : Quel rôle attribuable aux systèmes de santé ?

Abstract: Cette etude evalue l’influence des caracteristiques des systemes de sante sur l’equite horizontale du recours aux soins en Europe. L’utilisation d’un ensemble des donnees issues d’enquetes nationales recentes de treize pays europeens confirme l’existence d’inegalites sociales de recours aux soins, a besoin de soins egal, dans tous les pays etudies et montre que l’ampleur des inegalites varie de maniere significative entre les pays. Une analyse multiniveaux permet d’identifier differentes caracteristiques des systemes de sante qui semblent contribuer a la reduction ou a la formation de ces inegalites. Les resultats sou nt l’importance du role des medecins generalistes et de l’organisation des soins primaires pour reduire ces inegalites au-dela du partage des couts entre les spheres publique et privee.

Bayesian Optimal Adaptive Estimation Using a Sieve Prior

Abstract: We derive rates of contraction of posterior distributions on non-parametric models resulting from sieve priors. The aim of the study was to provide general conditions to get posterior rates when the parameter space has a general structure, and rate adaptation when the parameter is, for example, a Sobolev class. The conditions employed, although standard in the literature, are combined in a different way. The results are applied to density, regression, nonlinear autoregression and Gaussian white noise models. In the latter we have also considered a loss function which is different from the usual l2 norm, namely the pointwise loss. In this case it is possible to prove that the adaptive Bayesian approach for the l2 loss is strongly suboptimal and we provide a lower bound on the rate.

Macromarketing Issues on the Sidewalk: How “Gleaners” and “Disposers” (Re)Create a Sustainable Economy

Abstract: The aim of this research is to show that though French public policy advocates sustainable development, it unwittingly deters non-institutionalized sustainable practices. To illustrate this paradox, this research focuses on bulky item collection and the urban gleaning to which it gives rise. A qualitative study shows that urban gleaning comes into conflict with the hygiene norm that pre-exists concerns about sustainability. To ease these tensions and authorize themselves to glean, gleaners draw on a repertoire of justifications around sustainability that condemns waste and attributes altruistic intentions to disposers. In turn, to put their items out on the sidewalk, disposers must negotiate tensions in relation both to the hygiene norm (not polluting public space) and to the sustainability norm (not throwing away items that could still be used by other people). To justify their act, disposers construct an image of gleaners, to whom they can “pass on” their possessions. This double process appears to create a new form of sustainable circulation through which objects are redistributed and which has important implications for macromarketing.

Geometric properties of solutions to the total variation denoising problem

Abstract: This article studies the denoising performance of total variation (TV) image regularization. More precisely, we study geometrical properties of the solution to the so-called Rudin-Osher-Fatemi total variation denoising method. The first contribution of this paper is a precise mathematical definition of the "extended support" (associated to the noise-free image) of TV denoising. It is intuitively the region which is unstable and will suffer from the staircasing effect. We highlight in several practical cases, such as the indicator of convex sets, that this region can be determined explicitly. Our second and main contribution is a proof that the TV denoising method indeed restores an image which is exactly constant outside a small tube surrounding the extended support. The radius of this tube shrinks toward zero as the noise level vanishes, and are able to determine, in some cases, an upper bound on the convergence rate. For indicators of so-called "calibrable" sets (such as disks or properly eroded squares), this extended support matches the edges, so that discontinuities produced by TV denoising cluster tightly around the edges. In contrast, for indicators of more general shapes or for complicated images, this extended support can be larger. Beside these main results, our paper also proves several intermediate results about fine properties of TV regularization, in particular for indicators of calibrable and convex sets, which are of independent interest.