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High dimensional error covariance matrices and their inverses are used to weight the contribution of observation and background information in data assimilation procedures. As observation error covariance matrices are often obtained by…

Optimization and Control · Mathematics 2019-10-02 Jemima M. Tabeart , Sarah L. Dance , Amos S. Lawless , Nancy K. Nichols , Joanne A. Waller

An important class of nonlinear weighted least-squares problems arises from the assimilation of observations in atmospheric and ocean models. In variational data assimilation, inverse error covariance matrices define the weighting matrices…

Numerical Analysis · Mathematics 2022-12-06 Olivier Goux , Selime Gürol , Anthony T. Weaver , Oliver Guillet , Youssef Diouane

Data assimilation algorithms combine prior and observational information, weighted by their respective uncertainties, to obtain the most likely posterior of a dynamical system. In variational data assimilation the posterior is computed by…

Numerical Analysis · Mathematics 2021-05-24 Jemima M. Tabeart , Sarah L. Dance , Amos S. Lawless , Nancy K. Nichols , Joanne A. Waller

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

This study aims at introducing two conservative thermodynamic variables (moist-air entropy potential temperature and total water content) into a one-dimensional variational data assimilation system (1D-Var) to demonstrate the benefit for…

Atmospheric and Oceanic Physics · Physics 2022-04-12 Pascal Marquet , Pauline Martinet , Jean-François Mahfouf , Alina Lavinia Barbu , Benjamin Ménétrier

An Ensemble of Data Assimilations (EDA) can provide valuable information on the analysis and short-range forecast uncertainties. The present ECMWF operational ocean analysis and reanalysis system, called ORAS5, produces an ensemble but does…

Atmospheric and Oceanic Physics · Physics 2024-07-08 Marcin Chrust , Anthony T. Weaver , Philip Browne , Hao Zuo , Magdalena Alonso Balmaseda

Incremental 4D-Var is a data assimilation algorithm used routinely at operational numerical weather predictions centers worldwide.This paper implements a new method for parallelizing incremental 4D-Var, the Randomized Incremental Optimal…

Numerical Analysis · Mathematics 2024-09-23 Nicolas Bousserez , Jonathan J. Guerrette , Daven K. Henze

Autonomous driving systems are highly dependent on sensors like cameras, LiDAR, and inertial measurement units (IMU) to perceive the environment and estimate their motion. Among these sensors, perception-based sensors are not protected from…

Cross-correlation techniques provide a promising avenue for calibrating photometric redshifts and determining redshift distributions using spectroscopy which is systematically incomplete (e.g., current deep spectroscopic surveys fail to…

Instrumentation and Methods for Astrophysics · Physics 2012-01-20 Daniel J. Matthews , Jeffrey A. Newman

When exposure measurement error (EME), confounder measurement error (CME), or both are present, health effect estimates regarding exposure mixtures and critical exposure time-window may not represent the true effects. For example, in air…

Statistics Theory · Mathematics 2025-05-28 Honghyok Kim

Introduction: Methods now exist to detect residual confounding. One requires an "indicator" with two key properties: conditional independence of the outcome (given exposure and measured covariates) absent confounding and other model…

Methodology · Statistics 2015-10-26 W. Dana Flanders , Matthew J. Strickland , Mitchel Klein

Several popular computer vision (CV) datasets, specifically employed for Object Detection (OD) in autonomous driving tasks exhibit biases due to a range of factors including weather and lighting conditions. These biases may impair a model's…

Computer Vision and Pattern Recognition · Computer Science 2023-01-05 Aboli Marathe , Rahee Walambe , Ketan Kotecha

This article discusses aeroacoustic imaging methods based on correlation measurements in the frequency domain. Standard methods in this field assume that the estimated correlation matrix is superimposed with additive white noise. In this…

Signal Processing · Electrical Eng. & Systems 2020-12-30 Hans-Georg Raumer , Carsten Spehr , Thorsten Hohage , Daniel Ernst

Background: In clinical research, the Bland-Altman analysis is commonly used to assess agreement of metric measurements made by two or more techniques, devices or methods. The approach can also deal with repeated measurements per subject or…

Earth Observation (EO) data are increasingly used in policy analysis by enabling granular estimation of conditional average treatment effects (CATE). However, a challenge in EO-based causal inference is determining the scale of the input…

Machine Learning · Statistics 2025-03-18 Fucheng Warren Zhu , Connor T. Jerzak , Adel Daoud

Automated vehicles require an accurate perception of their surroundings for safe and efficient driving. Lidar-based object detection is a widely used method for environment perception, but its performance is significantly affected by…

Computer Vision and Pattern Recognition · Computer Science 2024-01-18 Raphael van Kempen , Tim Rehbronn , Abin Jose , Johannes Stegmaier , Bastian Lampe , Timo Woopen , Lutz Eckstein

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

Adaptive optics systems require a calibration procedure to operate, whether in closed loop or even more importantly in forward control. This calibration usually takes the form of an interaction matrix and is a measure of the response on the…

Instrumentation and Methods for Astrophysics · Physics 2021-01-15 Olivier Lai , Mark Chun , Ryan Dungee , Jessica Lu , Marcel Carbillet

State estimates from weak constraint 4D-Var data assimilation can vary significantly depending on the data and model error covariances. As a result, the accuracy of these estimates heavily depends on the correct specification of both model…

Methodology · Statistics 2025-04-28 Sandra R. Babyale , Jodi Mead , Donna Calhoun , Patricia O. Azike

Observation of redshifted 21-cm signals from neutral hydrogen holds the key to understanding the structure formation and its evolution during the reionization and post-reionization era. Apart from the presence of orders of magnitude larger…

Instrumentation and Methods for Astrophysics · Physics 2022-03-02 Jais Kumar , Prasun Dutta , Samir Choudhuri , Nirupam Roy
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