Browsing by Resource Type "doc-type:preprint"
Now showing items 1-20 of 154
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3D Analysis-suitable T-splines: definition, linear independence and m-graded local refinement
(2016-01)This paper addresses the linear independence of T-splines in three space dimensions. We give an abstract definition of analysis-suitability, and prove that it is equivalent to dual-compatibility, wich guarantees linear ... -
3D incompressible two-phase flow benchmark computations for rising droplets
(2014-03)We perform 3D incompressible two-phase flow simulations of rising droplets. Based on a similar 2D benchmark, a 3D benchmark configuration with two test cases is formulated in which we compare the flow solvers DROPS, NaSt3DGPF ... -
A bond order dissection ANOVA approach for efficient electronic structure calculations
(2014-03)In this article, we present a new decomposition approach for the efficient approximate calculation of the electronic structure problem for molecules. It is based on a dimension-wise decomposition of the space the underlying ... -
A full three dimensional numerical simulation of the sediment transport and the scouring at a rectangular obstacle
(2015-09)We employ a numerical simulation of the three-dimensional fluid flow and the simultaneous transport of sediment to reproduce current-driven sediment transport processes. In particular, the scouring at a rectangular obstacle ... -
A gradient sampling method on algebraic varieties and application to nonsmooth low-rank optimization
(2016-10)In this paper, a nonsmooth optimization method for locally Lipschitz functions on real algebraic varieties is developed. To this end, the set-valued map <em>ε</em>-conditional subdifferential <em>x</em> → ... -
A molecular dynamics study of cementitious calcium silicate hydrate (C-S-H) gels
(2007-05)In this article we study the polymerization of silicic acids (Si(OH)<sub>4</sub>) in the presence of calcium ions by molecular dynamics simulations. We focus on the formation and structure of cementitious calcium silicate ... -
A molecular dynamics study of the aluminosilicate chains structure in Al-rich calcium silicate hydrated (C-S-H) gels
(2007-11)Calcium silicate hydrated (C-S-H) gel is the principal binding phase of the cement paste and responsible for its strength. It is basically composed of silicate chains held together with CaO layers, where different guest ... -
A molecular dynamics study on the impact of defects and functionalization on the Young modulus of boron-nitride nanotubes
(2007)In this article, we examine the Young modulus of (6, <em>m</em>) boron-nitride nanotubes with vacancy and functionalization defects. We employ molecular dynamics simulations using the Parrinello-Rahman approach. To this ... -
A multilevel approach to the evolutionary generation of polycrystalline structures
(2015-11)The Poisson-Voronoi tesselation is commonly used as an approximation to the microstructure of polycrystalline material. Although simple, this approximation fails to respect basic physical properties observed empirically, ... -
A multiscale finite element method for Neumann problems in porous microstructures
(2015-01)In this paper we develop and analyze a Multiscale Finite Element Method (MsFEM) for problems in porous microstructures. By solving local problems throughout the domain we are able to construct a multiscale basis that can ... -
A new generalization of the P1 non-conforming FEM to higher polynomial degrees
(2015)This paper generalizes the non-conforming FEM of Crouzeix and Raviart and its fundamental projection property by a novel mixed formulation for the Poisson problem based on the Helmholtz decomposition. The new formulation ... -
A note on source term representation for control-and-state-constrained parabolic control problems with purely time-dependent control
(2022-06)We revisit the concept of source term representation, originally developed for boundary control problems subject to pointwise state constraints in the domain, and apply it to linear-quadratic parabolic control problems ... -
A note on the construction of L-fold sparse tensor product spaces
(2012-04)In the present paper, we consider the construction of general sparse tensor product spaces in arbitrary space dimensions when the single subdomains are of different dimensionality and the associated ansatz spaces possess ... -
A sparse grid based generative topographic mapping for the dimensionality reduction of high-dimensional data
(2012-05)Most high-dimensional data exhibit some correlation such that data points are not distributed uniformly in the data space but lie approximately on a lower-dimensional manifold. A major problem in many data-mining applications ... -
A wavelet based sparse grid method for the electronic Schrödinger equation
(2006-05)We present a direct discretization of the electronic Schrödinger equation. It is based on one-dimensional Meyer wavelets from which we build an anisotropic multiresolution analysis for general particle spaces by a tensor ... -
A-posteriori error estimation of discrete POD models for PDE-constrained optimal control
(2016-03)In this work a-posteriori error estimates for linear-quadratic optimal control problems governed by parabolic equations are considered. Different error estimation techniques for finite element discretizations and model-order ... -
A-posteriori reduced basis error-estimates for a semi-discrete in space quasilinear parabolic PDE
(2020-12)We prove a-posteriori error-estimates for reduced-order modeling of quasilinear parabolic PDEs with non-monotone nonlinearity. We consider the solution of a semi-discrete in space equation as reference, and therefore ... -
Adaptive mesh refinement strategies in isogeometric analysis: A computational comparison
(2016-05)We explain four variants of an adaptive finite element method with cubic splines and compare their performance in simple elliptic model problems. The methods in comparison are Truncated Hierarchical B-splines with two ... -
An adaptive multiscale approach for electronic structure methods
(2016)In this paper, we introduce a new scheme for the efficient numerical treatment of the electronic Schr¨odinger equation for molecules. It is based on the combination of a many-body expansion, which corresponds to the bond ... -
Additive Schwarz solvers for hp-FEM discretizations of PDE-constrained optimzation problems
(2016-10)In this paper, we investigate the minimization of a quadratic functional subject to a boundary value problem of a second order linear elliptic partial differential equation. There are no inequality constraints for state ...
