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Recent studies have shown that it is possible to combine machine learning methods with data assimilation to reconstruct a dynamical system using only sparse and noisy observations of that system. The same approach can be used to correct the…

Machine Learning · Statistics 2021-09-09 Alban Farchi , Marc Bocquet , Patrick Laloyaux , Massimo Bonavita , Quentin Malartic

Ensemble methods are among the state-of-the-art predictive modeling approaches. Applied to modern big data, these methods often require a large number of sub-learners, where the complexity of each learner typically grows with the size of…

Machine Learning · Computer Science 2018-10-29 Amichai Painsky , Saharon Rosset

This paper studies the role of sparse regularization in a properly chosen basis for variational data assimilation (VDA) problems. Specifically, it focuses on data assimilation of noisy and down-sampled observations while the state variable…

Data Analysis, Statistics and Probability · Physics 2014-06-25 A. M. Ebtehaj , M. Zupanski , G. Lerman , E. Foufoula-Georgiou

We propose new ensemble models for multivariate functional data classification as combinations of semi-metric-based weak learners. Our models extend current semi-metric-type methods from the univariate to the multivariate case, propose new…

Ensemble methods which average over multiple neural network predictions are a simple approach to improve a model's calibration and robustness. Similarly, data augmentation techniques, which encode prior information in the form of invariant…

Data assimilation algorithms integrate prior information from numerical model simulations with observed data. Ensemble-based filters, regarded as state-of-the-art, are widely employed for large-scale estimation tasks in disciplines such as…

Numerical Analysis · Mathematics 2024-05-24 Iris Rammelmüller , Gottfried Hastermann , Jana de Wiljes

Data augmentation is commonly used to encode invariances in learning methods. However, this process is often performed in an inefficient manner, as artificial examples are created by applying a number of transformations to all points in the…

Machine Learning · Computer Science 2019-03-04 Michael Kuchnik , Virginia Smith

Clustering is widely used in unsupervised learning to find homogeneous groups of observations within a dataset. However, clustering mixed-type data remains a challenge, as few existing approaches are suited for this task. This study…

Machine Learning · Statistics 2025-11-26 Badih Ghattas , Alvaro Sanchez San-Benito

Data assimilation (DA) estimates a dynamical system's state from noisy observations. Recent generative models like the ensemble score filter (EnSF) improve DA in high-dimensional nonlinear settings but are computationally expensive. We…

Machine Learning · Statistics 2025-09-30 Taos Transue , Bohan Chen , So Takao , Bao Wang

There are several bias mitigators that can reduce algorithmic bias in machine learning models but, unfortunately, the effect of mitigators on fairness is often not stable when measured across different data splits. A popular approach to…

Machine Learning · Computer Science 2022-02-03 Michael Feffer , Martin Hirzel , Samuel C. Hoffman , Kiran Kate , Parikshit Ram , Avraham Shinnar

Ensemble methods are known for enhancing the accuracy and robustness of machine learning models by combining multiple base learners. However, standard approaches like greedy or random ensembling often fall short, as they assume a constant…

Machine Learning · Computer Science 2025-06-24 Sebastian Pineda Arango , Maciej Janowski , Lennart Purucker , Arber Zela , Frank Hutter , Josif Grabocka

Ensembling deep learning models is a shortcut to promote its implementation in new scenarios, which can avoid tuning neural networks, losses and training algorithms from scratch. However, it is difficult to collect sufficient accurate and…

Machine Learning · Computer Science 2020-12-04 Jun Yang , Fei Wang

The ensemble of deep neural networks has been shown, both theoretically and empirically, to improve generalization accuracy on the unseen test set. However, the high training cost hinders its efficiency since we need a sufficient number of…

Machine Learning · Computer Science 2021-12-28 Wentao Zhang , Jiawei Jiang , Yingxia Shao , Bin Cui

Federated learning is a machine learning paradigm in which multiple devices collaboratively train a model under the supervision of a central server while ensuring data privacy. However, its performance is often hindered by redundant,…

Computer Vision and Pattern Recognition · Computer Science 2026-04-30 Emre Ardıç , Yakup Genç

Ensemble smoothers are among the most successful and efficient techniques currently available for history matching. However, because these methods rely on Gaussian assumptions, their performance is severely degraded when the prior geology…

Accurate characterization of subsurface heterogeneity is important for the safe and effective implementation of geological carbon storage (GCS) projects. This paper explores how machine learning methods can enhance data assimilation for GCS…

We introduce a score-filter-enhanced data assimilation framework designed to reduce predictive uncertainty in machine learning (ML) models for data-driven dynamical system forecasting. Machine learning serves as an efficient numerical model…

Dynamical Systems · Mathematics 2026-03-17 Jingqiao Tang , Ryan Bausback , Feng Bao , Guannan Zhang , Phuoc-Toan Huynh

In this paper, we propose two new algorithms for maximum-likelihood estimation (MLE) of high dimensional sparse covariance matrices. Unlike most of the state of-the-art methods, which either use regularization techniques or penalize the…

Methodology · Statistics 2023-05-12 Ghania Fatima , Prabhu Babu , Petre Stoica

There has been a recent surge in development of accurate machine learning (ML) weather prediction models, but evaluation of these models has mainly been focused on medium-range forecasts, not their performance in cycling data assimilation…

Atmospheric and Oceanic Physics · Physics 2024-12-25 Laura C. Slivinski , Jeffrey S. Whitaker , Sergey Frolov , Timothy A. Smith , Niraj Agarwal

Ensemble Kalman methods were initially developed to solve nonlinear data assimilation problems in oceanography, but are now popular in applications far beyond their original use cases. Of particular interest is climate model calibration. As…

Data Analysis, Statistics and Probability · Physics 2025-11-21 Rebecca Gjini , Matthias Morzfeld , Oliver R. A. Dunbar , Tapio Schneider