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This paper advances the study of multivariate function approximation using neural network operators activated by symmetrized and perturbed hyperbolic tangent functions. We propose new non-linear operators that preserve dynamic symmetries…

General Mathematics · Mathematics 2025-01-29 Rômulo Damasclin Chaves dos Santos , Jorge Henrique de Oliveira Sales

We introduce algorithms for learning nonlinear dynamical systems of the form $x_{t+1}=\sigma(\Theta^{\star}x_t)+\varepsilon_t$, where $\Theta^{\star}$ is a weight matrix, $\sigma$ is a nonlinear link function, and $\varepsilon_t$ is a…

Machine Learning · Computer Science 2020-05-01 Dylan J. Foster , Alexander Rakhlin , Tuhin Sarkar

We develop an algorithm based on the nudging data assimilation scheme for the concurrent (on-the-fly) estimation of scalar parameters for a system of evolutionary dissipative partial differential equations in which the state is partially…

Numerical Analysis · Mathematics 2025-06-16 Benjamin Pachev , Jared P. Whitehead , Shane A. McQuarrie

In this paper we present a novel quasi-Newton algorithm for use in stochastic optimisation. Quasi-Newton methods have had an enormous impact on deterministic optimisation problems because they afford rapid convergence and computationally…

Systems and Control · Electrical Eng. & Systems 2019-09-04 Adrian Wills , Thomas Schön

In this paper we propose a solution to the problem of parameter estimation of nonlinearly parameterized regressions--continuous or discrete time--and apply it for system identification and adaptive control. We restrict our attention to…

Optimization and Control · Mathematics 2019-10-18 Romeo Ortega , Vladislav Gromov , Emmanuel Nuño , Anton Pyrkin , Jose Guadalupe Romero

In this paper, we study the convergence properties of an iterative algorithm for fast nonlinear model predictive control of quasi-linear parameter-varying systems without inequality constraints. Compared to previous works considering this…

Optimization and Control · Mathematics 2023-09-15 Christian Hespe , Herbert Werner

We study iterative signal reconstruction in computed tomography (CT), wherein measurements are produced by a linear transformation of the unknown signal followed by an exponential nonlinear map. Approaches based on pre-processing the data…

Optimization and Control · Mathematics 2024-07-19 Vasileios Charisopoulos , Rebecca Willett

Data assimilation provides a systematic framework for combining dynamical models with partial and noisy observations to infer the evolving state of a system. In this work, we undertake a comparative study of Data Assimilation with Transfer…

Computational Engineering, Finance, and Science · Computer Science 2026-05-07 Emanuele Donno , Giovanni Conti , Paolo Oddo , Silvio Gualdi , Luca Mainetti , Giovanni Aloisio

We investigate mathematically a nonlinear approximation type approach recently introduced in [A. Ammar et al., J. Non-Newtonian Fluid Mech., 2006] to solve high dimensional partial differential equations. We show the link between the…

Numerical Analysis · Mathematics 2008-11-05 C. Le Bris , T. Lelievre , Y. Maday

Nonlinear differential equations model diverse phenomena but are notoriously difficult to solve. While there has been extensive previous work on efficient quantum algorithms for linear differential equations, the linearity of quantum…

We evaluate the benefits of combining different offline and online data assimilation methodologies to improve personalized blood glucose prediction with type 2 diabetes self-monitoring data. We collect self-monitoring data (nutritional…

Quantitative Methods · Quantitative Biology 2017-09-04 Matthew E Levine , George Hripcsak , Lena Mamykina , Andrew Stuart , David J Albers

Nonlinear/non-Gaussian filtering has broad applications in many areas of life sciences where either the dynamic is nonlinear and/or the probability density function of uncertain state is non-Gaussian. In such problems, the accuracy of the…

Computation · Statistics 2012-08-02 Hatef Monajemi , Peter K. Kitanidis

While the formulation of most data assimilation schemes assumes an unbiased observation model error, in real applications, model error with nontrivial biases is unavoidable. A practical example is the error in the radiative transfer model…

Methodology · Statistics 2016-11-17 John Harlim , Tyrus Berry

In this paper, we consider nonconvex optimization problems with nonsmooth nonconvex objective function and nonlinear equality constraints. We assume that both the objective function and the functional constraints can be separated into 2…

Optimization and Control · Mathematics 2025-03-04 Lahcen El Bourkhissi , Ion Necoara

An algorithm for a family of self-starting high-order implicit time integration schemes with controllable numerical dissipation is proposed for both linear and nonlinear transient problems. This work builds on the previous works of the…

Numerical Analysis · Mathematics 2024-09-23 Daniel O'Shea , Xiaoran Zhang , Shayan Mohammadian , Chongmin Song

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

We develop a fast and robust algorithm for solving large scale convex composite optimization models with an emphasis on the $\ell_1$-regularized least squares regression (Lasso) problems. Despite the fact that there exist a large number of…

Optimization and Control · Mathematics 2017-05-04 Xudong Li , Defeng Sun , Kim-Chuan Toh

Many important applications, including signal reconstruction, parameter estimation, and signal processing in a compressed domain, rely on a low-dimensional representation of the dataset that preserves {\em all} pairwise distances between…

Machine Learning · Statistics 2016-09-20 Jarosław Błasiok , Charalampos E. Tsourakakis

This paper considers a nudging-based scheme for data assimilation for the two-dimensional (2D) Navier-Stokes equations (NSE) with periodic boundary conditions and studies the synchronization of the signal produced by this algorithm with the…

Analysis of PDEs · Mathematics 2022-08-02 Animikh Biswas , Kenneth R. Brown , Vincent R. Martinez

Data assimilation involves estimating the state of a system by combining observations from various sources with a background estimate of the state. The weights given to the observations and background state depend on their specified error…

Numerical Analysis · Mathematics 2025-03-13 Olivier Goux , Anthony Weaver , Selime Gürol , Oliver Guillet , Andrea Piacentini