University of Marne-la-Vallée

About: University of Marne-la-Vallée is a based out in . It is known for research contribution in the topics: Estimator & Context (language use). The organization has 831 authors who have published 1855 publications receiving 55316 citations.

Finite deformations of Ogden's materials under impact loading

Abstract: The present paper is devoted to the modeling of finite deformations of a hyperelastic body described by Ogden's model under contact/impact conditions. Frictional contact problems are solved by means of the bi-potential method. The first order algorithm is applied to integrate the equation of motion. The total Lagrangian formulation is adopted to describe the geometrically non-linear behavior. For the finite element implementation, the explicit expression of the tangent operator is derived including the case of repeated eigenvalues. A numerical example is given to illustrate efficiency and accuracy of the method.

Infimum-convolution description of concentration properties of product probability measures, with applications

Abstract: This paper is devoted to the concentration properties of product probability measures mu = mu(1) circle times(...)circle times mu(n), expressed in term of dimension-free functional inequalities of the form [GRAPHICS] where a is a parameter, 0 < alpha < 1, and Q(alpha)f is an appropriate infimum-convolution operator. This point of view has been introduced by Maurey [B. Maurey, Some deviation inequalities, Geom. Funct: Anal. 1 (1991) 188-197]. It has its origins in concentration inequalities by Talagrand where the enlargement of sets is done in accordance with the cost function of the operator Q alpha f (see [M. Talagrand, Concentration of measure and isoperimetric, inequalities in product spaces, Publ. Math. Inst. Hautes Etudes Sci. 81 (1995) 73-205, M. Talagrand, New concentration inequalities in product spaces, Invent. Math. 126 *(1996) 505-563, M. Talagrand, A new look at independence, Ann. Probab. 24 (1996) 1-34]). A main application of the functional inequalities obtained here is optimal deviations inequalities for suprema of sums of independent random variables. As example, we also derive classical deviations bounds for the one-dimensional bin packing problem. (c) 2006 Elsevier Masson SAS. All rights reserved.

Improving Convergence of the Hastings–Metropolis Algorithm with an Adaptive Proposal

Abstract: The Hastings-Metropolis algorithm is a general MCMC method for sampling from a density known up to a constant. Geometric convergence of this algorithm has been proved under conditions relative to the instrumental (or proposal) distribution. We present an inhomogeneous Hastings-Metropolis algorithm for which the proposal density approximates the target density, as the number of iterations increases. The proposal density at the nth step is a non-parametric estimate of the density of the algorithm, and uses an increasing number of i.i.d. copies of the Markov chain. The resulting algorithm converges (in n) geometrically faster than a Hastings-Metropolis algorithm with any fixed proposal distribution. The case of a strictly positive density with compact support is presented first, then an extension to more general densities is given. We conclude by proposing a practical way of implementation for the algorithm, and illustrate it over simulated examples.

q-Identities from Lagrange and Newton Interpolation

Abstract: Combining Newton and Lagrange interpolation, we give $q$-identities which generalize results of Van Hamme, Uchimura, Dilcher and Prodinger.