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Modeling of sound propagation in media with azimuthal variations of the material parameters typically necessitates approximations. Useful methods, such as the 3-D parabolic equation (PE) method, need verification by correct reference…

Geophysics · Physics 2019-04-11 Sven M. Ivansson

In several recent works \cite{Causley2013a}, \cite{Causley2013}, we developed a new second order, A-stable approach to wave propagation problems based on the method of lines transpose (MOL$^T$) formulation combined with alternating…

Numerical Analysis · Mathematics 2013-08-15 Matthew F. Causley , Andrew J. Christlieb

The phenomena that emerge from the interaction of the stochastic opening and closing of ion channels (channel noise) with the non-linear neural dynamics are essential to our understanding of the operation of the nervous system. The effects…

Neurons and Cognition · Quantitative Biology 2012-05-29 Patricio Orio , Daniel Soudry

This paper provides a rigorous derivation and analysis of accelerated optimization algorithms through the lens of High-Resolution Ordinary Differential Equations (ODEs). While classical Nesterov acceleration is well-understood via…

Optimization and Control · Mathematics 2025-12-30 Kewang Chen , Yongqiu Jiang , Kees Vuik

We introduce new adaptive artificial anti-diffusion (AAAD) methods for one- and two-dimensional hyperbolic systems of conservation laws. The key idea is to reduce the amount of numerical dissipation present in a given numerical method by…

Numerical Analysis · Mathematics 2026-05-18 Shaoshuai Chu , Igor Kliakhandler , Alexander Kurganov

In this report, we present a versatile and efficient preconditioned Anderson acceleration (PAA) method for fixed-point iterations. The proposed framework offers flexibility in balancing convergence rates (linear, super-linear, or quadratic)…

Numerical Analysis · Mathematics 2023-10-09 Kewang Chen , Ye Ji , Matthias Möller , Cornelis Vuik

Stochastic approximation (SA) is a method for finding the root of an operator perturbed by noise. There is a rich literature establishing the asymptotic normality of rescaled SA iterates under fairly mild conditions. However, these…

Machine Learning · Statistics 2026-02-17 Shaan Ul Haque , Zedong Wang , Zixuan Zhang , Siva Theja Maguluri

This paper introduces a novel method for numerically stabilizing sequential continuous adjoint flow solvers utilizing an elliptic relaxation strategy. The proposed approach is formulated as a Partial Differential Equation (PDE) containing a…

Fluid Dynamics · Physics 2025-01-23 Niklas Kühl

This paper develops validated computational methods for studying infinite dimensional stable manifolds at equilibrium solutions of parabolic PDEs, synthesizing disparate errors resulting from numerical approximation. To construct our…

Dynamical Systems · Mathematics 2021-07-08 Jan Bouwe van den Berg , Jonathan Jaquette , J. D. Mireles James

We present an extension of the AAA (adaptive Antoulas--Anderson) algorithm for periodic functions, called 'AAAtrig'. The algorithm uses the key steps of AAA approximation by (i) representing the approximant in (trigonometric) barycentric…

Numerical Analysis · Mathematics 2020-08-13 Peter J. Baddoo

In this study, a Fourier-based, split-step Pad\'e (SSP) method for solving the parabolic wave equation with applications in guided wave propagation in ocean acoustics is presented. Traditional SSP implementations rely in finite-difference…

Numerical Analysis · Mathematics 2025-11-06 Daniel Walsken , Pavel Petrov , Matthias Ehrhardt

We consider the finite element (FE) approximation of the shallow water equations (SWE) by considering discretizations in which both space and time are established using an unconditionally stable FE method. Particularly, we consider the…

Numerical Analysis · Mathematics 2021-11-18 Eirik Valseth , Clint Dawson

We consider the Adaptive Antoulas-Anderson (AAA) rational interpolation algorithm recently developed by Trefethen and co-authors, which can be viewed as a type of moment-matching technique for system realization and approximation. We…

Systems and Control · Electrical Eng. & Systems 2023-10-03 Jared Jonas , Bassam Bamieh

Fractional differential equations (FDEs) describe subdiffusion behavior of dynamical systems. Its non-local structure requires taking into account the whole evolution history during the time integration, which then possibly causes…

Numerical Analysis · Mathematics 2022-02-17 Ustim Khristenko , Barbara Wohlmuth

In this paper, we propose and analyze a set of fully non-stationary Anderson acceleration algorithms with dynamic window sizes and optimized damping. Although Anderson acceleration (AA) has been used for decades to speed up nonlinear…

Numerical Analysis · Mathematics 2022-03-29 Kewang Chen , Cornelis Vuik

This paper is concerned with the comparison of semi-analytical and non-averaged propagation methods for Earth satellite orbits. We analyse the total integration error for semi-analytical methods and propose a novel decomposition into…

Earth and Planetary Astrophysics · Physics 2019-05-23 Davide Amato , Claudio Bombardelli , Giulio Baù , Vincent Morand , Aaron J. Rosengren

Over-water communication has been an important research field of wireless communications and radar. Since there are so many parameters in this environment that are changing continuously in the spatial and temporal domains such as weather…

Signal Processing · Electrical Eng. & Systems 2018-12-27 Ahmed Abdelmoaty

In this letter, we investigate the direction-of-arrival (DOA) estimation problem for wireless sensing with movable antenna (MA) systems in the presence of unknown antenna position errors (APE). To achieve robust wireless sensing, we…

Signal Processing · Electrical Eng. & Systems 2026-05-25 Chengzhi Ye , Ruoyu Zhang , Wen Wu , Byonghyo Shim

Simulations of the dynamics generated by partial differential equations (PDEs) provide approximate, numerical solutions to initial value problems. Such simulations are ubiquitous in scientific computing, but the correctness of the results…

Numerical Analysis · Mathematics 2026-01-09 Jan Bouwe van den Berg , Maxime Breden

We introduce an automatic variationally stable analysis (AVS) for finite element (FE) computations of scalar-valued convection-diffusion equations with non-constant and highly oscillatory coefficients. In the spirit of least squares FE…

Numerical Analysis · Mathematics 2019-04-16 Victor M. Calo , Albert Romkes , Eirik Valseth