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This paper focuses on discussing Newton's method and its hybrid with machine learning for the steady state Navier-Stokes Darcy model discretized by mixed element methods. First, a Newton iterative method is introduced for solving the…

Numerical Analysis · Mathematics 2024-03-07 Jianguo Huang , Hui Peng , Haohao Wu

This paper focuses on continuous data assimilation (CDA) for the Navier-Stokes equations with nonlinear slip boundary conditions. CDA methods are typically employed to recover the original system when initial data or viscosity coefficients…

Numerical Analysis · Mathematics 2025-03-28 W. C. Wu , H. Y. Dong , K. Wang

Sparse sensor networks in weather and ocean modeling observe only a small fraction of the system state, which destabilizes standard nudging-based data assimilation. We introduce Interpolated Discrepancy Data Assimilation (IDDA), which…

Numerical Analysis · Mathematics 2025-11-03 Tong Wu , Humberto Godinez , Vitaliy Gyrya , James M. Hyman

Data assimilation is the process to fuse information from priors, observations of nature, and numerical models, in order to obtain best estimates of the parameters or state of a physical system of interest. Presence of large errors in some…

Numerical Analysis · Mathematics 2015-11-06 Vishwas Rao , Adrian Sandu , Michael Ng , Elias Nino-Ruiz

Computational models of atmospheric composition are not always physically consistent. For example, not all models respect fundamental conservation laws such as conservation of atoms in an interconnected chemical system. In well performing…

Atmospheric and Oceanic Physics · Physics 2024-08-30 Patrick Obin Sturm , Sam J. Silva

Shape-morphing solutions (also known as evolutional deep neural networks, reduced-order nonlinear solutions, and neural Galerkin schemes) are a new class of methods for approximating the solution of time-dependent partial differential…

Numerical Analysis · Mathematics 2025-04-08 Zachary T. Hilliard , Mohammad Farazmand

This article develops a general framework for continuous deterministic data assimilation for semilinear parabolic equations by means of evolution equations. Introducing a nudged model driven by partial observations, the global…

Analysis of PDEs · Mathematics 2026-02-25 Gianmarco Del Sarto , Matthias Hieber , Filippo Palma , Tarek Zöchling

A variational data assimilation technique was used to estimate optimal discretization of interpolation operators and derivatives in the nodes adjacent to the rigid boundary. Assimilation of artificially generated observational data in the…

Atmospheric and Oceanic Physics · Physics 2012-12-17 Eugene Kazantsev

Image denoising is a fundamental problem in computational photography, where achieving high perception with low distortion is highly demanding. Current methods either struggle with perceptual quality or suffer from significant distortion.…

Computer Vision and Pattern Recognition · Computer Science 2024-11-19 Tong Li , Hansen Feng , Lizhi Wang , Zhiwei Xiong , Hua Huang

Accurate estimation of error covariances (both background and observation) is crucial for efficient observation compression approaches in data assimilation of large-scale dynamical problems. We propose a new combination of a covariance…

Numerical Analysis · Mathematics 2021-06-11 Sibo Cheng , Didier Lucor , Jean-Philippe Argaud

Many large-scale and distributed optimization problems can be brought into a composite form in which the objective function is given by the sum of a smooth term and a nonsmooth regularizer. Such problems can be solved via a proximal…

Optimization and Control · Mathematics 2020-06-26 Sepideh Hassan-Moghaddam , Mihailo R. Jovanović

We consider fully discrete numerical schemes for a downscaling data assimilation algorithm aimed at approximating the velocity field of the 2D Navier-Stokes equations corresponding to given coarse mesh observational measurements. The time…

Numerical Analysis · Mathematics 2018-05-07 Hussain A. Ibdah , Cecilia F. Mondaini , Edriss S. Titi

We discuss the discrete data assimilation problem for the 3D viscous primitive equations arising in the modeling of large scale phenomena in oceanic dynamics. Our main result states possibility of asymptotically reliable prognosis based on…

Dynamical Systems · Mathematics 2013-08-08 Igor Chueshov

Brownian Dynamics algorithms are widely used for simulating soft-matter and biochemical systems. In recent times, their application has been extended to the simulation of coarse-grained models of cellular networks in simple organisms. In…

Quantitative Methods · Quantitative Biology 2009-11-13 Marco J. Morelli , Pieter Rein ten Wolde

We propose closed-form conditional diffusion models for data assimilation. Diffusion models use data to learn the score function (defined as the gradient of the log-probability density of a data distribution), allowing them to generate new…

Machine Learning · Statistics 2026-04-02 Brianna Binder , Agnimitra Dasgupta , Assad Oberai

Multiscale dynamics are ubiquitous in applications of modern science. Because of time scale separation between relatively small set of slowly evolving variables and (typically) much larger set of rapidly changing variables, direct numerical…

Dynamical Systems · Mathematics 2016-04-08 Rafail V. Abramov

Non-spherical particles transported by an anisotropic turbulent flow preferentially align with the mean shear and intermittently tumble when the local strain fluctuates. Such an intricate behaviour is here studied for inertialess,…

Soft Condensed Matter · Physics 2022-12-27 Lorenzo Campana , Mireille Bossy , Jeremie Bec

Data assimilation addresses the general problem of how to combine model-based predictions with partial and noisy observations of the process in an optimal manner. This survey focuses on sequential data assimilation techniques using…

Numerical Analysis · Mathematics 2019-08-15 Sebastian Reich

We introduce a data assimilation strategy aimed at accurately capturing key non-Gaussian structures in probability distributions using a small ensemble size. A major challenge in statistical forecasting of nonlinearly coupled multiscale…

Numerical Analysis · Mathematics 2025-04-01 Di Qi , Jian-Guo Liu

With the increasing penetration of high-frequency sensors across a number of biological and physical systems, the abundance of the resulting observations offers opportunities for higher statistical accuracy of down-stream estimates, but…

Optimization and Control · Mathematics 2020-11-06 Shushu Zhang , Vivak Patel
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