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The analog signals generated in the read-out electronics of radiation detectors are shaped prior to the digitization in order to improve the signal to noise ratio (SNR). The real amplitude of the analog signal is then obtained using digital…

Instrumentation and Detectors · Physics 2019-03-07 J. L. Ortiz , F. Carrió , A. Valero

Channel estimation and beamforming play critical roles in frequency-division duplexing (FDD) massive multiple-input multiple-output (MIMO) systems. However, these two modules have been treated as two stand-alone components, which makes it…

Signal Processing · Electrical Eng. & Systems 2021-08-04 Yifan Ma , Yifei Shen , Xianghao Yu , Jun Zhang , S. H. Song , Khaled B. Letaief

Lightweight neural networks for single-image super-resolution (SISR) tasks have made substantial breakthroughs in recent years. Compared to low-frequency information, high-frequency detail is much more difficult to reconstruct. Most SISR…

Image and Video Processing · Electrical Eng. & Systems 2023-03-22 Xiaotian Weng , Yi Chen , Zhichao Zheng , Yanhui Gu , Junsheng Zhou , Yudong Zhang

RES, a regularized stochastic version of the Broyden-Fletcher-Goldfarb-Shanno (BFGS) quasi-Newton method is proposed to solve convex optimization problems with stochastic objectives. The use of stochastic gradient descent algorithms is…

Machine Learning · Computer Science 2015-06-18 Aryan Mokhtari , Alejandro Ribeiro

Federated learning (FL) enables collaborative machine learning across distributed data owners, but data heterogeneity poses a challenge for model calibration. While prior work focused on improving accuracy for non-iid data, calibration…

Machine Learning · Computer Science 2024-06-05 Hongyi Peng , Han Yu , Xiaoli Tang , Xiaoxiao Li

Federated learning (FL) is a useful tool in distributed machine learning that utilizes users' local datasets in a privacy-preserving manner. When deploying FL in a constrained wireless environment; however, training models in a…

Machine Learning · Computer Science 2022-05-06 Jake Perazzone , Shiqiang Wang , Mingyue Ji , Kevin Chan

For federated learning (FL) algorithms such as FedSAM, their generalization capability is crucial for real-word applications. In this paper, we revisit the generalization problem in FL and investigate the impact of data heterogeneity on FL…

Machine Learning · Computer Science 2026-04-21 Liu junkang , Yuanyuan Liu , Fanhua Shang , Hongying Liu , Jin Liu , Wei Feng

We propose an L-BFGS optimization algorithm on Riemannian manifolds using minibatched stochastic variance reduction techniques for fast convergence with constant step sizes, without resorting to linesearch methods designed to satisfy Wolfe…

Optimization and Control · Mathematics 2017-05-23 Anirban Roychowdhury

Signal artefacts due to Radio Frequency Interference (RFI) are a common nuisance in radio astronomy. Conventionally, the RFI-affected data are tagged by an expert data analyst in order to warrant data quality. In view of the increasing data…

Instrumentation and Methods for Astrophysics · Physics 2018-08-30 Paul Ray Burd , Karl Mannheim , Tobias März , Jonas Ringholz , Alexander Kappes , Matthias Kadler

Calibrating out per-antenna signal chain effects is an essential step in analyzing radio interferometric data. For drift-scanning arrays, robustly calibrating the data is especially challenging due to the lack of the ability to track a…

Instrumentation and Methods for Astrophysics · Physics 2026-02-09 Robert Pascua , Jonathan Sievers , Adrian Liu

Multiple-input multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) is a key technology component in the evolution towards cognitive radio (CR) in next-generation communication in which the accuracy of timing and frequency…

Signal Processing · Electrical Eng. & Systems 2022-06-02 Jun Liu , Kai Mei , Xiaochen Zhang , Des McLernon , Dongtang Ma , Jibo Wei , Syed Ali Raza Zaidi

We propose a generic framework to calibrate accuracy and confidence of a prediction in deep neural networks through stochastic inferences. We interpret stochastic regularization using a Bayesian model, and analyze the relation between…

Machine Learning · Computer Science 2019-04-25 Seonguk Seo , Paul Hongsuck Seo , Bohyung Han

Context: Interferometric imaging is algorithmically and computationally challenging as there is no unique inversion from the measurement data back to the sky maps, and the datasets can be very large. Many imaging methods already exist, but…

Instrumentation and Methods for Astrophysics · Physics 2024-10-23 Jakob Roth , Philipp Frank , Hertzog L. Bester , Oleg M. Smirnov , Rüdiger Westermann , Torsten A. Enßlin

Radio resource management in cellular networks is typically based on device measurements reported to the serving base station. Frequent measuring of signal quality on available frequencies would allow for highly reliable networks and…

Applications · Statistics 2019-03-04 Caroline Svahn , Oleg Sysoev , Mirsad Čirkić , Fredrik Gunnarsson , Joel Berglund

Aims: We address two issues for the adoption of convex optimization in radio interferometric imaging. First, a method for a fine resolution setup is proposed which scales naturally in terms of memory usage and reconstruction speed. Second,…

Instrumentation and Methods for Astrophysics · Physics 2025-01-22 Adrian Jarret , Sepand Kashani , Joan Rué-Queralt , Paul Hurley , Julien Fageot , Matthieu Simeoni

Calibration of a typical radio interferometric array yields thousands of parameters as solutions. These solutions contain valuable information about the systematic errors in the data (ionosphere and beam shape). This information could be…

Instrumentation and Methods for Astrophysics · Physics 2018-01-31 Sarod Yatawatta

Radio frequency interference (RFI) is the principal factor limiting the sensitivities of radio telescopes, particularly at frequencies below 1 GHz. I present a conceptually new approach to mitigation of RFI in interferometric data. This has…

Instrumentation and Methods for Astrophysics · Physics 2011-02-11 Ramana Athreya

Federated learning (FL), which has gained increasing attention recently, enables distributed devices to train a common machine learning (ML) model for intelligent inference cooperatively without data sharing. However, problems in practical…

Machine Learning · Computer Science 2022-11-01 Yujie Zhou , Zhidu Li , Tong Tang , Ruyan Wang

This paper presents a new, low-complexity algorithm for time and frequency synchronization in a non-contiguous-orthogonal frequency division multiplexing (NC-OFDM) radio communication system in the presence of narrowband interference (NBI).…

Social and Information Networks · Computer Science 2021-04-26 Pawel Kryszkiewicz , Hanna Bogucka

The aim of the new generation of radio synthesis arrays such as LOFAR and SKA is to achieve much higher sensitivity, resolution and frequency coverage than what is available now, especially at low frequencies. To accomplish this goal, the…

Instrumentation and Methods for Astrophysics · Physics 2015-05-20 S. Kazemi , S. Yatawatta , S. Zaroubi , A. G. de Bruyn , L. V. E. Koopmans , J. Noordam
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