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Distributed radio interferometric calibration based on consensus optimization has been shown to improve the estimation of systematic errors in radio astronomical observations. The intrinsic continuity of systematic errors across frequency…

Instrumentation and Methods for Astrophysics · Physics 2017-10-17 Sarod Yatawatta , Faruk Diblen , Hanno Spreeuw

In this paper, we present results on improving out-of-domain weather prediction and uncertainty estimation as part of the \texttt{Shifts Challenge on Robustness and Uncertainty under Real-World Distributional Shift} challenge. We find that…

Machine Learning · Computer Science 2024-01-10 Sankalp Gilda , Neel Bhandari , Wendy Mak , Andrea Panizza

A major stage of radio interferometric data processing is calibration or the estimation of systematic errors in the data and the correction for such errors. A stochastic error (noise) model is assumed, and in most cases, this underlying…

Instrumentation and Methods for Astrophysics · Physics 2015-06-16 S. Kazemi , S. Yatawatta

High precison calibration is essential for a new generation of radio interferometers looking for Epoch of Reionization and Baryon Acoustic Oscillation signatures in neutral hydrogen. These arrays have so far been calibrated by redundant…

Instrumentation and Methods for Astrophysics · Physics 2017-01-10 J. L. Sievers

In this work, we investigate direction finding in the presence of sensor gain uncertainties and directional perturbations for sensor array processing in a multi-frequency scenario. Specifically, we adopt a distributed optimization scheme in…

Signal Processing · Electrical Eng. & Systems 2020-02-27 Martin Brossard , Virginie Ollier , Mohammed Nabil El Korso , Rémy Boyer , Pascal Larzabal

Modern deep neural networks can produce badly calibrated predictions, especially when train and test distributions are mismatched. Training an ensemble of models and averaging their predictions can help alleviate these issues. We propose a…

Machine Learning · Computer Science 2020-07-09 Asa Cooper Stickland , Iain Murray

The generalization performance of a risk prediction model can be evaluated by its calibration, which measures the agreement between predicted and observed outcomes on external validation data. Here, methods for assessing the calibration of…

Methodology · Statistics 2020-01-31 Moritz Berger , Matthias Schmid

Distributed antennas must be phase-calibrated (phase-synchronized) for certain operations, such as reciprocity-based joint coherent downlink beamforming, to work. We use rigorous signal processing tools to analyze the accuracy of…

Information Theory · Computer Science 2024-01-23 Erik G. Larsson

I present in this paper a method to calibrate data obtained from optical and infrared interferometers. I show that correlated noises and errors need to be taken into account for a very good estimate of individual error bars but also when…

Astrophysics · Physics 2009-11-07 G. Perrin

The volume of radio-astronomical data is a considerable burden in the processing and storing of radio observations with high time and frequency resolutions and large bandwidths. Lossy compression of interferometric radio-astronomical data…

Instrumentation and Methods for Astrophysics · Physics 2016-11-09 A. R. Offringa

Low-frequency radio observatories are reaching unprecedented levels of sensitivity in an effort to detect the 21 cm signal from the Cosmic Dawn. High precision is needed because the expected signal is overwhelmed by foreground…

Instrumentation and Methods for Astrophysics · Physics 2022-03-14 Adam E. Lanman , Steven G. Murray , Daniel C. Jacobs

Distributed algorithms for solving additive or consensus optimization problems commonly rely on first-order or proximal splitting methods. These algorithms generally come with restrictive assumptions and at best enjoy a linear convergence…

Optimization and Control · Mathematics 2017-05-11 Sina Khoshfetrat Pakazad , Christian A. Naesseth , Fredrik Lindsten , Anders Hansson

Distributional regression aims at estimating the conditional distribution of a targetvariable given explanatory co-variates. It is a crucial tool for forecasting whena precise uncertainty quantification is required. A popular methodology…

Statistics Theory · Mathematics 2024-11-22 Clément Dombry , Ahmed Zaoui

The Square Kilometre Array (SKA) will form the largest radio telescope ever built and such a huge instrument in the desert poses enormous engineering and logistic challenges. Algorithmic and architectural breakthroughs are needed. Data is…

Instrumentation and Methods for Astrophysics · Physics 2014-11-17 Orhan Ocal , Paul Hurley , Giovanni Cherubini , Sanaz Kazemi

A probabilistic model is said to be calibrated if its predicted probabilities match the corresponding empirical frequencies. Calibration is important for uncertainty quantification and decision making in safety-critical applications. While…

Machine Learning · Computer Science 2020-07-01 Anusri Pampari , Stefano Ermon

One of the biggest challenges in operating massive multiple-input multiple-output systems is the acquisition of accurate channel state information at the transmitter. To take up this challenge, time division duplex is more favorable thanks…

Information Theory · Computer Science 2024-10-30 Xiwen Jiang , Alexis Decurninge , Kalyana Gopala , Florian Kaltenberger , Maxime Guillaud , Dirk Slock , Luc Deneire

Direction dependent calibration and imaging is a vital part of producing deep, high fidelity, high-dynamic range radio images with a wide-field low-frequency array like LOFAR. Currently, state-of-the-art facet-based direction dependent…

Instrumentation and Methods for Astrophysics · Physics 2020-03-25 J. G. Albert , R. J. van Weeren , H. T. Intema , H. J. A. Röttgering

In the context of computer models, calibration is the process of estimating unknown simulator parameters from observational data. Calibration is variously referred to as model fitting, parameter estimation/inference, an inverse problem, and…

Methodology · Statistics 2023-10-16 Richard D. Wilkinson , Christopher W. Lanyon

The task of calibration is to retrospectively adjust the outputs from a machine learning model to provide better probability estimates on the target variable. While calibration has been investigated thoroughly in classification, it has not…

Machine Learning · Statistics 2018-06-21 Hao Song , Meelis Kull , Peter Flach

The Random Forest (RF) classifier is often claimed to be relatively well calibrated when compared with other machine learning methods. Moreover, the existing literature suggests that traditional calibration methods, such as isotonic…

Machine Learning · Computer Science 2025-01-29 Mohammad Hossein Shaker , Eyke Hüllermeier