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We propose and analyze a hybridized discontinuous Galerkin (HDG) method for the spherically symmetric Einstein--scalar system in Bondi gauge. After rewriting the model as a local first-order PDE--ODE system by introducing suitable scaled…

Numerical Analysis · Mathematics 2026-04-07 Mukul Dwivedi , Andreas Rupp

We present an algebraic method for constructing a highly effective coarse grid correction to accelerate domain decomposition. The coarse problem is constructed from the original matrix and a small set of input vectors that span a low-degree…

Numerical Analysis · Computer Science 2015-04-06 Essex Edwards , Robert Bridson

A conforming discontinuous Galerkin (DG) finite element method has been introduced in [21] on simplicial meshes, which has the flexibility of using discontinuous approximation and the simplicity in formulation of the classic continuous…

Numerical Analysis · Mathematics 2019-07-11 Xiu Ye , Shangyou Zhang

When the heat released by a flame is sufficiently in phase with the acoustic pressure, a self-excited thermoacoustic oscillation can arise. These nonlinear oscillations are one of the biggest challenges faced in the design of safe and…

Computational Engineering, Finance, and Science · Computer Science 2019-06-28 Tullio Traverso , Luca Magri

In this paper, we study superconvergence properties of the discontinuous Galerkin (DG) method for one-dimensional linear hyperbolic equation when upwind fluxes are used. We prove, for any polynomial degree $k$, the $2k+1$th (or $2k+1/2$th)…

Numerical Analysis · Mathematics 2013-11-28 Cao Waixiang , Zhang Zhimin , Zou Qingsong

We analyse instabilities due to aliasing errors when solving one dimensional non-constant advection speed equations and discuss means to alleviate these types of errors when using high order discontinuous Galerkin (DG) schemes. First, we…

Numerical Analysis · Mathematics 2017-05-04 Juan Manzanero , Gonzalo Rubio , Esteban Ferrer , Eusebio Valero , David A. Kopriva

We present discontinuous Galerkin (DG) methods for solving a first-order semi-linear hyperbolic system, which was originally proposed as a continuum model for a one-dimensional dimer lattice of topological resonators. We examine the…

Numerical Analysis · Mathematics 2023-05-23 Qiang Du , Huaiyu Li , Michael Weinstein , Lu Zhang

Domain adaption (DA) and domain generalization (DG) are two closely related methods which are both concerned with the task of assigning labels to an unlabeled data set. The only dissimilarity between these approaches is that DA can access…

Computer Vision and Pattern Recognition · Computer Science 2018-12-27 Mohammad Mahfujur Rahman , Clinton Fookes , Mahsa Baktashmotlagh , Sridha Sridharan

Unstructured grid ocean models are advantageous for simulating the coastal ocean and river-estuary-plume systems. However, unstructured grid models tend to be diffusive and/or computationally expensive which limits their applicability to…

Atmospheric and Oceanic Physics · Physics 2018-10-31 Tuomas Kärnä , Stephan C. Kramer , Lawrence Mitchell , David A. Ham , Matthew D. Piggott , António M. Baptista

We introduce a new class of Discontinuous Galerkin (DG) methods for solving nonlinear conservation laws on unstructured Voronoi meshes that use a nonconforming Virtual Element basis defined within each polygonal control volume. The basis…

Numerical Analysis · Mathematics 2025-01-24 Walter Boscheri , Giulia Bertaglia

Flood simulation and forecast capability have been greatly improved thanks to advances in data assimilation (DA) strategies incorporating various types of observations; many are derived from spatial Earth Observation. This paper focuses on…

Image and Video Processing · Electrical Eng. & Systems 2023-11-30 Thanh Huy Nguyen , Sophie Ricci , Andrea Piacentini , Ehouarn Simon , Raquel Rodriguez Suquet , Santiago Peña Luque

Numerical solvers using adaptive meshes can focus computational power on important regions of a model domain capturing important or unresolved physics. The adaptation can be informed by the model state, external information, or made to…

Applications · Statistics 2021-05-12 Christian Sampson , Alberto Carrassi , Ali Aydoğdu , Chris K. R. T Jones

Generative data augmentation (GDA) has emerged as a promising technique to alleviate data scarcity in machine learning applications. This thesis presents a comprehensive survey and unified framework of the GDA landscape. We first provide an…

Machine Learning · Computer Science 2024-04-23 Yunhao Chen , Zihui Yan , Yunjie Zhu

In this work, we analyze an unfitted discontinuous Galerkin discretization for the numerical solution of the Stokes system based on equal higher-order discontinuous velocities and pressures. This approach combines the best from both worlds,…

Numerical Analysis · Mathematics 2022-04-06 Aikaterini Aretaki , Efthymios N. Karatzas , Georgios Katsouleas

This work aims at presenting a Discontinuous Galerkin (DG) formulation employing a spectral basis for two important models employed in cardiac electrophysiology, namely the monodomain and bidomain models. The use of DG methods is motivated…

Numerical Analysis · Mathematics 2025-03-24 Federica Botta , Matteo Calafà , Pasquale C. Africa , Christian Vergara , Paola F. Antonietti

Machine learning models struggle with generalization when encountering out-of-distribution (OOD) samples with unexpected distribution shifts. For vision tasks, recent studies have shown that test-time adaptation employing diffusion models…

Computer Vision and Pattern Recognition · Computer Science 2024-04-03 Yun-Yun Tsai , Fu-Chen Chen , Albert Y. C. Chen , Junfeng Yang , Che-Chun Su , Min Sun , Cheng-Hao Kuo

The high-order numerical solution of the non-linear shallow water equations (and of hyperbolic systems in general) is susceptible to unphysical Gibbs oscillations that form in the proximity of strong gradients. The solution to this problem…

Numerical Analysis · Mathematics 2016-07-18 Simone Marras , Michal A. Kopera , Emil M. Constantinescu , Jenny Suckale , Francis X. Giraldo

The use of machine learning (ML) models in meteorology has attracted significant attention for their potential to improve weather forecasting efficiency and accuracy. GraphCast and NeuralGCM, two promising ML-based weather models, are at…

Atmospheric and Oceanic Physics · Physics 2024-11-25 Xiaoxu Tian , Daniel Holdaway , Daryl Kleist

In this paper, we present convergence analysis of high-order finite element based methods, in particular, we focus on a discontinuous Galerkin scheme using summation-by-parts operators. To this end, it is crucial that structure preserving…

Numerical Analysis · Mathematics 2022-03-07 Mária Lukácová-Medvidová , Philipp Öffner

The classical arguments employed when obtaining error estimates of Finite Element (FE) discretisations of elliptic problems lead to more restrictive assumptions on the regularity of the exact solution when applied to non-conforming methods.…

Numerical Analysis · Mathematics 2024-11-25 J. Blechta , P. A. Gazca-Orozco , A. Kaltenbach , M. Růžička