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Accurate numerical solutions of the equations of hydrodynamics play an ever more important role in many fields of astrophysics. In this work, we reinvestigate the accuracy of the moving-mesh code \textsc{Arepo} and show how its convergence…

We propose regularization schemes for deformable registration and efficient algorithms for their numerical approximation. We treat image registration as a variational optimal control problem. The deformation map is parametrized by its…

Optimization and Control · Mathematics 2016-09-09 Andreas Mang , George Biros

Dynamical stabilizer codes may offer a practical route to large-scale quantum computation. Such codes are defined by a schedule of error-detecting measurements, which allows for flexibility in their construction. In this work, we ask how…

Label noise presents a real challenge for supervised learning algorithms. Consequently, mitigating label noise has attracted immense research in recent years. Noise robust losses is one of the more promising approaches for dealing with…

Machine Learning · Computer Science 2021-04-27 Neta Shoham , Tomer Avidor , Nadav Israel

We introduce a model-based iterative method to obtain shear modulus images of tissue using magnetic resonance elastography. The method jointly finds the displacement field that best fits multifrequency tissue displacement data and the…

Signal Processing · Electrical Eng. & Systems 2021-11-25 Shahed Mohammed , Mohammad Honarvar , Qi Zeng , Hoda Hashemi , Robert Rohling , Piotr Kozlowski , Septimiu Salcudean

In certain astrophysical systems the commonly employed ideal magnetohydrodynamics (MHD) approximation breaks down. Here, we introduce novel explicit and implicit numerical schemes of ohmic resistivity terms in the moving-mesh code AREPO. We…

Instrumentation and Methods for Astrophysics · Physics 2018-03-09 Federico Marinacci , Mark Vogelsberger , Rahul Kannan , Philip Mocz , Rüdiger Pakmor , Volker Springel

Noise generation attributed to the flow around a cylinder and its control is of paramount importance in a multitude of engineering applications. In this study, we employ computational fluid dynamics (CFD) coupled with acoustic analogy,…

Fluid Dynamics · Physics 2023-10-23 Yongxi Wu , Guangnian Ji , Peizhi Zhang

Regularization is essential for avoiding over-fitting to training data in network optimization, leading to better generalization of the trained networks. The label noise provides a strong implicit regularization by replacing the target…

Machine Learning · Computer Science 2022-05-04 Kensuke Nakamura , Bong-Soo Sohn , Kyoung-Jae Won , Byung-Woo Hong

The accuracy of finite element solutions is closely tied to the mesh quality. In particular, geometrically nonlinear problems involving large and strongly localized deformations often result in prohibitively large element distortions. In…

Computational Engineering, Finance, and Science · Computer Science 2024-05-30 Abhiroop Satheesh , Christoph P. Schmidt , Wolfgang A. Wall , Christoph Meier

The Reynolds equation, combined with the Elrod algorithm for including the effect of cavitation, resembles a nonlinear convection-diffusion-reaction (CDR) equation. Its solution by finite elements is prone to oscillations in…

Numerical Analysis · Mathematics 2023-10-12 Hauke Gravenkamp , Simon Pfeil , Ramon Codina

Centroidal Voronoi tessellation (CVT)-based mesh generation is a very effective technique for creating high-quality Voronoi meshes and their dual Delaunay triangulations that often play a crucial role in applications, including ocean and…

Numerical Analysis · Mathematics 2018-05-23 Huanhuan Yang , Max Gunzburger , Lili Ju

In this paper we show that simple noise regularisation can be an effective way to address GNN oversmoothing. First we argue that regularisers addressing oversmoothing should both penalise node latent similarity and encourage meaningful node…

This work considers charged systems described by the modified Poisson--Nernst--Planck (PNP) equations, which incorporate ionic steric effects and the Born solvation energy for dielectric inhomogeneity. Solving the steady-state modified PNP…

Numerical Analysis · Mathematics 2025-06-04 Zhonghua Qiao , Zhenli Xu , Qian Yin , Shenggao Zhou

In this work, we illustrate the connection between adaptive mesh refinement for finite element discretized PDEs and the recently developed \emph{bi-level regularization algorithm}. By adaptive mesh refinement according to data noise,…

Numerical Analysis · Mathematics 2025-10-15 Christian Aarset , Tram Thi Ngoc Nguyen

We consider the problem of recovering the surface wave profile from noisy bottom pressure measurements with (\textit{a priori} unknown) arbitrary pressure at the surface. Without noise, the direct approach developed in…

Fluid Dynamics · Physics 2024-02-14 Joris Labarbe , Alexandre Vieira , Didier Clamond

Gravitational lens modeling of spatially resolved sources is a challenging inverse problem with many observational constraints and model parameters. We examine established pixel-based source reconstruction algorithms for de-lensing the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-22 Amitpal Tagore , Charles Keeton

Noise bias is a significant source of systematic error in weak gravitational lensing measurements that must be corrected to satisfy the stringent standards of modern imaging surveys in the era of precision cosmology. This paper reviews the…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-09 Xiangchong Li , Rachel Mandelbaum , The LSST Dark Energy Science Collaboration

We consider the problem of regularization by noise for the three dimensional magnetohydrodynamical (3D MHD) equations. It is shown that, in a suitable scaling limit, multiplicative noise of transport type gives rise to bounds on the…

Probability · Mathematics 2022-11-22 Dejun Luo

Magnetic fields play an important role in astrophysics on a wide variety of scales, ranging from the Sun and compact objects to galaxies and galaxy clusters. Here we discuss a novel implementation of ideal magnetohydrodynamics (MHD) in the…

Instrumentation and Methods for Astrophysics · Physics 2015-05-30 Ruediger Pakmor , Andreas Bauer , Volker Springel

Optimization, a key tool in machine learning and statistics, relies on regularization to reduce overfitting. Traditional regularization methods control a norm of the solution to ensure its smoothness. Recently, topological methods have…

Machine Learning · Computer Science 2020-11-11 Arnur Nigmetov , Aditi S. Krishnapriyan , Nicole Sanderson , Dmitriy Morozov