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We consider multiscale stochastic dynamical systems. In this article an \emph{intermediate} reduced model is obtained for a slow-fast system with fast mode driven by white noise. First, the reduced stochastic system on exponentially…

Mathematical Physics · Physics 2009-03-10 W. Wang , A. J. Roberts

Functional bilevel methods estimate a lower-level function and plug it into a hypergradient, but this plug-in gradient can retain first-order bias when the lower-level problem is learned nonparametrically. To remove this bias, we develop a…

Machine Learning · Statistics 2026-05-21 Fares El Khoury , Houssam Zenati , Nathan Kallus , Michael Arbel , Aurélien Bibaut

This work is concerned with the recovery of piecewise constant images from noisy linear measurements. We study the noise robustness of a variational reconstruction method, which is based on total (gradient) variation regularization. We show…

Numerical Analysis · Mathematics 2025-07-08 Yohann De Castro , Vincent Duval , Romain Petit

Aggregate outcome variables collected through surveys and administrative records are often subject to systematic measurement error. For instance, in disaster loss databases, county-level losses reported may differ from the true damages due…

Machine Learning · Computer Science 2026-03-17 Saketh Vishnubhatla , Shu Wan , Andre Harrison , Adrienne Raglin , Huan Liu

The widespread use of machine learning and data-driven algorithms for decision making has been steadily increasing over many years. \emph{Bias} in the data can adversely affect this decision-making. We present a new mitigation strategy to…

Machine Learning · Computer Science 2025-07-25 Bruno Scarone , Alfredo Viola , Renée J. Miller , Ricardo Baeza-Yates

This paper addresses variational data assimilation from a learning point of view. Data assimilation aims to reconstruct the time evolution of some state given a series of observations, possibly noisy and irregularly-sampled. Using automatic…

Computational Physics · Physics 2021-11-10 Ronan Fablet , Bertrand Chapron , Lucas. Drumetz , Etienne Memin , Olivier Pannekoucke , Francois Rousseau

In meteorology, engineering and computer sciences, data assimilation is routinely employed as the optimal way to combine noisy observations with prior model information for obtaining better estimates of a state, and thus better forecasts,…

Geophysics · Physics 2009-08-12 M. J. Werner , K. Ide , D. Sornette

Current deep learning-based manifold learning algorithms such as the variational autoencoder (VAE) require fully sampled data to learn the probability density of real-world datasets. Once learned, the density can be used for a variety of…

Image and Video Processing · Electrical Eng. & Systems 2021-12-13 Qing Zou , Abdul Haseeb Ahmed , Prashant Nagpal , Sarv Priya , Rolf Schulte , Mathews Jacob

Power electronic devices such as HVDC and FACTS can be used to improve the damping of poorly damped inter-area modes in large power systems. This involves the use of wide-area feedback signals, which are transmitted via communication…

Systems and Control · Electrical Eng. & Systems 2022-11-17 K. K. Gajjar , Kaustav Dey , A. M. Kulkarni

Using a high degree of parallelism is essential to perform data assimilation efficiently. The state formulation of the incremental weak constraint four-dimensional variational data assimilation method allows parallel calculations in the…

Numerical Analysis · Mathematics 2021-08-19 Ieva Daužickaitė , Amos S. Lawless , Jennifer A. Scott , Peter Jan van Leeuwen

Weak quantum measurements enable real-time tracking and control of dynamical quantum systems, producing quantum trajectories -- evolutions of the quantum state of the system conditioned on measurement outcomes. For classical systems, the…

Bias field, which is caused by imperfect MR devices or imaged objects, introduces intensity inhomogeneity into MR images and degrades the performance of MR image analysis methods. Many retrospective algorithms were developed to facilitate…

Image and Video Processing · Electrical Eng. & Systems 2023-08-01 Dong Liang , Xingyu Qiu , Kuanquan Wang , Gongning Luo , Wei Wang , Yashu Liu

In this work, an efficient numerical scheme is presented for seismic blind deconvolution in a multichannel scenario. The proposed method iterate with wo steps: first, wavelet estimation across all channels and second, refinement of the…

Computational Physics · Physics 2020-10-20 Naveed Iqbal , Entao Liu , James H. McClellan , Abdullatif A. Al-Shuhail

Autoresonance is a phenomenon of physical interest that may take place when a nonlinear oscillator is forced at a frequency that varies slowly. The stroboscopic averaging method (SAM), which provides an efficient numerical technique for the…

Numerical Analysis · Mathematics 2024-10-02 M. P. Calvo , J. M. Sanz-Serna , Beibei Zhu

A challenge arising from the local Bayesian assimilation of data in an atmospheric flow simulation is the imbalances it may introduce. Acoustic fast-mode imbalances of the order of the slower dynamics can be negated by employing a blended…

Numerical Analysis · Mathematics 2024-03-11 Ray Chew , Tommaso Benacchio , Gottfried Hastermann , Rupert Klein

For massive multiple-input multiple-output (MIMO) systems operating in frequency-division duplex mode, downlink channel state information (CSI) acquisition will incur large overhead. This overhead is substantially reduced when sparse…

Signal Processing · Electrical Eng. & Systems 2022-03-29 Pengxia Wu , Julian Cheng

The analysis of high-dimensional dynamical systems generally requires the integration of simulation data with experimental measurements. Experimental data often has substantial amounts of measurement noise that compromises the ability to…

Numerical Analysis · Mathematics 2019-10-02 Samuel Rudy , Steven Brunton , J. Nathan Kutz

The weakly supervised sound event detection problem is the task of predicting the presence of sound events and their corresponding starting and ending points in a weakly labeled dataset. A weak dataset associates each training sample (a…

Sound · Computer Science 2021-06-22 Mohammad Rasool Izadi , Robert Stevenson , Laura N. Kloepper

Graph states are entangled states useful for several quantum information processing tasks such as measurement-based quantum computation and quantum metrology. As the size of graph states realized in experiments increases, it becomes more…

Quantum Physics · Physics 2023-09-18 Tomonori Tanizawa , Yuki Takeuchi , Shion Yamashika , Ryosuke Yoshii , Shunji Tsuchiya

Improved estimation of hydrometeorological states from down-sampled observations and background model forecasts in a noisy environment, has been a subject of growing research in the past decades. Here, we introduce a unified framework that…

Data Analysis, Statistics and Probability · Physics 2014-09-15 Ardeshir Mohammad Ebtehaj , Efi Foufoula-Georgiou