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Higher-order convex approximations of Young measures in optimal control
(2001)FIM's preprintsReport -
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Sparse adaptive Taylor approximation algorithms for parametric and stochastic elliptic PDEs
(2011)Research ReportsThe numerical approximation of parametric partial differential equations is a computational challenge, in particular when the number of involved parameter is large. This paper considers a model class of second order, linear, parametric, elliptic PDEs on a bounded domain D with diffusion coefficients depending on the parameters in an affine manner. For such models, it was shown in [11, 12] that under very weak assumptions on the diffusion ...Report -
Multi-Level Monte Carlo Finite Volume methods for uncertainty quantification of acoustic wave propagation in random heterogeneous layered medium
(2014)Research ReportWe consider the very challenging problem of efficient uncertainty quantification for acoustic wave propagation in a highly heterogeneous, possibly layered, random medium, characterized by possibly anisotropic, piecewise log-exponentially distributed Gaussian random fields. A multi-level Monte Carlo finite volume method is proposed, along with a novel, bias-free upscaling technique that allows to represent the input random fields, generated ...Report -
Exponential convergence of the hp version of isogeometric analysis in 1D
(2012)Research ReportWe review the recent results of [21, 22], and establish the exponential convergence of hp-version discontinuous Galerkin finite element methods for the numerical approximation of linear second-order elliptic boundary-value problems with homogeneous Dirichlet boundary conditions and constant coefficients in threedimsional and axiparallel polyhedra. The exponential rates are confirmed in a series of numerical tests.Report -
Exponential convergence of simplicial hp-FEM for H^1-functions with isotropic singularities
(2015)Lecture Notes in Computational Science and Engineering ~ Spectral and High Order Methods for Partial Differential Equations (ICOSAHOM 2014)For functions u ∈ H 1(Ω) in an open, bounded polyhedron Ω⊂Rd of dimension d = 1, 2, 3, which are analytic in Ω¯¯¯¯∖S with point singularities concentrated at the set S⊂Ω¯¯¯¯ consisting of a finite number of points in Ω¯¯¯¯, the exponential rate exp(−bN−−√d+1) of convergence of h p-version continuous Galerkin finite element methods on families of regular, simplicial meshes in Ω can be achieved. The simplicial meshes are assumed to be ...Report -
Multi-level Monte Carlo finite volume methods for uncertainty quantification in nonlinear systems of balance laws
(2012)Research ReportReport -
Higher order Quasi Monte Carlo integration for holomorphic, parametric operator equations
(2014)Research ReportWe analyze the convergence of higher order Quasi-Monte Carlo (QMC) quadratures of solution-functionals to countably-parametric, nonlinear operator equations with distributed uncertain parameters taking values in a separable Banach space X. Such equations arise in numerical uncertainty quantification with random field inputs. Unconditional bases of X render the random inputs and the solutions of the forward problem countably parametric. ...Report -
Computational Higher Order Quasi-Monte Carlo Integration
(2014)Research ReportThe efficient construction of higher-order interlaced polynomial lattice rules introduced recently in [4] is considered. After briefly reviewing the principles of their construction by the “fast component-by-component” (CBC) algorithm due to [1, 10] as well as recent theoretical results on their convergence rates, we indicate algorithmic details of their construction. Instances of such rules are applied to highdimensional test integrands ...Report -
Scaling Limits in Computational Bayesian Inversion
(2014)Research ReportComputational Bayesian inversion of operator equations with distributed uncertain input parameters is based on an infinite-dimensional version of Bayes’ formula established in [31] and its numerical realization in [27, 28]. Based on the sparsity of the posterior density shown in [29], dimensionadaptive Smolyak quadratures afford higher convergence rates than MCMC in terms of the number M of solutions of the forward (parametric operator) ...Report