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Nudging is an empirical data assimilation technique that incorporates an observation-driven control term into the model dynamics. The trajectory of the nudged system approaches the true system trajectory over time, even when the initial…

Machine Learning · Computer Science 2025-08-11 Jaemin Oh , Jinsil Lee , Youngjoon Hong

We present an efficient computational framework to quantify the impact of individual observations in four dimensional variational data assimilation. The proposed methodology uses first and second order adjoint sensitivity analysis, together…

Computational Engineering, Finance, and Science · Computer Science 2013-07-22 Alexandru Cioaca , Adrian Sandu

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

Many robotic tasks involving some form of 3D visual perception greatly benefit from a complete knowledge of the working environment. However, robots often have to tackle unstructured environments and their onboard visual sensors can only…

Computer Vision and Pattern Recognition · Computer Science 2022-10-24 Andrea Rosasco , Stefano Berti , Fabrizio Bottarel , Michele Colledanchise , Lorenzo Natale

Accurately estimating expectation values of quantum observables with as few measurements as possible is crucial to many quantum computing applications. We introduce a framework that covers many of existing measurement strategies and…

Shadows are common aspect of images and when left undetected can hinder scene understanding and visual processing. We propose a simple yet effective approach based on reflectance to detect shadows from single image. An image is first…

Computer Vision and Pattern Recognition · Computer Science 2018-07-13 Sri Kalyan Yarlagadda , Fengqing Zhu

We introduce three new nonlinear continuous data assimilation algorithms. These models are compared with the linear continuous data assimilation algorithm introduced by Azouani, Olson, and Titi (AOT). As a proof-of-concept for these models,…

Analysis of PDEs · Mathematics 2017-03-13 Adam Larios , Yuan Pei

Ensemble data assimilation techniques form an indispensable part of numerical weather prediction. As the ensemble size grows and model resolution increases, the amount of required storage becomes a major issue. Data compression schemes may…

Obtaining accurate high-resolution representations of model outputs is essential to describe the system dynamics. In general, however, only spatially- and temporally-coarse observations of the system states are available. These observations…

Dynamical Systems · Mathematics 2022-11-08 Mohamad Abed El Rahman Hammoud , Olivier LeMaitre , Edriss S. Titi , Ibrahim Hoteit , Omar Knio

Data assimilation is a core component of numerical weather prediction systems. The large quantity of data processed during assimilation requires the computation to be distributed across increasingly many compute nodes, yet existing…

Machine Learning · Computer Science 2025-01-15 Oscar Key , So Takao , Daniel Giles , Marc Peter Deisenroth

This paper studies first-order algorithms for solving fully composite optimization problems over convex and compact sets. We leverage the structure of the objective by handling its differentiable and non-differentiable components…

Optimization and Control · Mathematics 2023-07-13 Maria-Luiza Vladarean , Nikita Doikov , Martin Jaggi , Nicolas Flammarion

While single image shadow detection has been improving rapidly in recent years, video shadow detection remains a challenging task due to data scarcity and the difficulty in modelling temporal consistency. The current video shadow detection…

Computer Vision and Pattern Recognition · Computer Science 2021-08-02 Shilin Hu , Hieu Le , Dimitris Samaras

For oceanographic applications, probabilistic forecasts typically have to deal with i) high-dimensional complex models, and ii) very sparse spatial observations. In search-and-rescue operations at sea, for instance, the short-term…

Applications · Statistics 2023-02-15 Florian Beiser , Håvard Heitlo Holm , Jo Eidsvik

We address the problem of 3D shape completion from sparse and noisy point clouds, a fundamental problem in computer vision and robotics. Recent approaches are either data-driven or learning-based: Data-driven approaches rely on a shape…

Computer Vision and Pattern Recognition · Computer Science 2018-11-28 David Stutz , Andreas Geiger

The Strong Constraint 4D Variational (SC-4DVAR) data assimilation method is widely used in climate and weather applications. SC-4DVAR involves solving a minimization problem to compute the maximum a posteriori estimate, which we tackle…

Numerical Analysis · Mathematics 2025-06-16 Amit N. Subrahmanya , Vishwas Rao , Arvind K. Saibaba

Recent advances in the theory of Neural Operators (NOs) have enabled fast and accurate computation of the solutions to complex systems described by partial differential equations (PDEs). Despite their great success, current NO-based…

Machine Learning · Computer Science 2024-03-18 Ashutosh Singh , Ricardo Augusto Borsoi , Deniz Erdogmus , Tales Imbiriba

In quantum information theory, the accurate estimation of observables is pivotal for quantum information processing, playing a crucial role in compute and communication protocols. This work introduces a novel technique for estimating such…

Quantum Physics · Physics 2024-09-17 Andrea Caprotti , Joshua Morris , Borivoje Dakić

Data assimilation performance can be significantly impacted by biased noise in observations, altering the signal magnitude and introducing fast oscillations or discontinuities when the system lacks smoothness. To mitigate these issues, this…

Numerical Analysis · Mathematics 2024-11-05 Felipe Galarce , Joaquin Mura , Alfonso Caiazzo

Performing Data Assimilation (DA) at a low cost is of prime concern in Earth system modeling, particularly at the time of big data where huge quantities of observations are available. Capitalizing on the ability of Neural Networks…

Machine Learning · Computer Science 2021-11-24 Mathis Peyron , Anthony Fillion , Selime Gürol , Victor Marchais , Serge Gratton , Pierre Boudier , Gael Goret

Data assimilation combines (imperfect) knowledge of a flow's physical laws with (noisy, time-lagged, and otherwise imperfect) observations to produce a more accurate prediction of flow statistics. Assimilation by nudging (from 1964), while…

Numerical Analysis · Mathematics 2024-07-31 Aytekin Çıbık , Rui Fang , William Layton , Farjana Siddiqua