Results 1 to 10 of about 329,451 (151)

Wavenumber-Explicit <i>hp</i>-FEM Analysis for Maxwell's Equations with Impedance Boundary Conditions. [PDF]

Found Comut Math, 2023
The time-harmonic Maxwell equations at high wavenumber k in domains with an analytic boundary and impedance boundary conditions are considered. A wavenumber-explicit stability and regularity theory is developed that decomposes the solution into a part ...
Melenk JM, Sauter SA.
europepmc   +2 more sources

Benchmarking Hybrid CNN-Transformer Versus Pure Transformer Architectures for Accelerated Hyperpolarized ¹²⁹Xe MRI Reconstruction. [PDF]

J Magn Reson Imaging
ABSTRACT Background Hyperpolarized 129Xe MRI faces technical challenges including low signal‐to‐noise ratio and breath‐hold constraints. Current literature focuses on proprietary deep learning methods or image‐domain enhancements. Purpose To present a comprehensive evaluation of transformer and hybrid CNN‐transformer architectures integrating dual ...
Babaeipour R, Fox MS, Parraga G, Ouriadov A.   +3 more
europepmc   +2 more sources

High-Power Terahertz Emission from Picosecond Nano-Plasma Switching Driven by Secondary Electron Emission Avalanche. [PDF]

Adv Sci (Weinh)
A nano‐plasma device enables watt‐level on‐chip THz generation through picosecond switching triggered by secondary electron emission avalanche. An ultra‐dense electron sheet initiates nano‐plasma formation within a ∼100 nm gap, driving rapid energy release into an integrated resonator.
Sun G, Rezaei M, Hu Y, Zhang GJ, Matioli E.   +4 more
europepmc   +2 more sources

The hp-FEM applied to the Helmholtz equation with PML truncation does not suffer from the pollution effect [PDF]

Communications in Mathematical Sciences, 2022
We consider approximation of the variable-coefficient Helmholtz equation in the exterior of a Dirichlet obstacle using perfectly-matched-layer (PML) truncation; it is well known that this approximation is exponentially accurate in the PML width and the ...
J. Galkowski, D. Lafontaine, E. Spence, J. Wunsch   +3 more
semanticscholar   +1 more source

A simple proof that the hp-FEM does not suffer from the pollution effect for the constant-coefficient full-space Helmholtz equation [PDF]

Advances in Computational Mathematics, 2022
In d dimensions, accurately approximating an arbitrary function oscillating with frequency ≲ k $\lesssim k$ requires ∼ k d $\sim k^{d}$ degrees of freedom.
E. Spence
semanticscholar   +1 more source

Exponential Convergence of hp FEM for the Integral Fractional Laplacian in Polygons [PDF]

SIAM Journal on Numerical Analysis, 2022
We prove exponential convergence in the energy norm of $hp$ finite element discretizations for the integral fractional diffusion operator of order $2s\in (0,2)$ subject to homogeneous Dirichlet boundary conditions in bounded polygonal domains $\Omega ...
M. Faustmann, C. Marcati, J. Melenk, C. Schwab   +3 more
semanticscholar   +1 more source

An exponentially convergent discretization for space-time fractional parabolic equations using hp-FEM [PDF]

arXiv.org, 2022
We consider a space-time fractional parabolic problem. Combining a sinc-quadrature based method for discretizing the Riesz-Dunford integral with $hp$-FEM in space yields an exponentially convergent scheme for the initial boundary value problem with ...
J. Melenk, A. Rieder
semanticscholar   +1 more source

Exponential convergence of hp-FEM for the integral fractional Laplacian in 1D [PDF]

arXiv.org, 2022
We prove weighted analytic regularity for the solution of the integral fractional Poisson problem on bounded intervals with analytic right-hand side. Based on this regularity result, we prove exponential convergence of the hp-FEM on geometric boundary ...
M. Faustmann, C. Marcati, J. Melenk, C. Schwab   +3 more
semanticscholar   +1 more source

Minimization of energy functionals via FEM: implementation of hp-FEM [PDF]

Large-Scale Scientific Computing, 2023
Many problems in science and engineering can be rigorously recast into minimizing a suitable energy functional. We have been developing efficient and flexible solution strategies to tackle various minimization problems by employing finite element ...
Miroslav Frost, Alexej Moskovka, J. Valdman   +2 more
semanticscholar   +1 more source

Parallel genetic algorithm finding optimal initial mesh for three dimensional self-adaptive hp finite element method [PDF]

Computer Methods in Materials Science, 2011
In this paper we investigate the parallel version of the hierarchical chromosome based genetic algorithm (HCBGA) for finding the optimal initial mesh for self-adaptive hp-Finite Element Method (hp-FEM).
Anna Paszyńska, Maciej Paszyński
doaj   +1 more source