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Broadband beamforming is a technique to obtain the signal with a wide range of frequencies. It maintains the signal integrity and spatial selectivity over frequencies. This is important in several applications such as microphone array,…

Signal Processing · Electrical Eng. & Systems 2020-03-03 Phan Le Son

Iterative projection algorithms are successfully being used as a substitute of lenses to recombine, numerically rather than optically, light scattered by illuminated objects. Images obtained computationally allow aberration-free…

Optics · Physics 2007-05-23 S. Marchesini

The optical nonlinear effects can provide different advanced electromagnetic functionalities, such as wave mixing and phase conjugation, which can be applied in a variety of new applications. However, these effects usually suffer from…

Optics · Physics 2020-06-29 Boyuan Jin , Christos Argyropoulos

In this paper, we study a fast approximate inference method based on expectation propagation for exploring the posterior probability distribution arising from the Bayesian formulation of nonlinear inverse problems. It is capable of…

Numerical Analysis · Mathematics 2015-06-18 Matthias Gehre , Bangti Jin

State-of-the-art adaptive optics (AO) systems perform non-linear Fourier-type wavefront sensing for real-time corrections of dynamic wavefront aberrations. This general class of sensors uses a filtering mask in the focal plane that converts…

Instrumentation and Methods for Astrophysics · Physics 2025-06-24 Victoria Laidlaw

Future radar systems are expected to use waveforms of a high bandwidth, where the main advantage is an improved range resolution. In this paper, a technique to design robust wideband waveforms for a Multiple-Input-Single-Output system is…

Applications · Statistics 2016-11-17 Ashkan Panahi , Marie Ström , Mats Viberg

We develop a new methodology for the deterministic forecasting of directional ocean surface waves, based on nonlinear frequency corrections. These frequency corrections can be pre-computed based on measured energy density spectra, and…

Atmospheric and Oceanic Physics · Physics 2023-06-26 Eytan Meisner , Mariano Galvagno , David Andrade , Dan Liberzon , Raphael Stuhlmeier

Next generation radio-interferometers, like the Square Kilometre Array, will acquire tremendous amounts of data with the goal of improving the size and sensitivity of the reconstructed images by orders of magnitude. The efficient processing…

Instrumentation and Methods for Astrophysics · Physics 2017-05-26 Alexandru Onose , Arwa Dabbech , Yves Wiaux

(Abridged) Context: In the previous paper in this series, we identified that a pentagonal arrangement of five telescopes, using a kernel-nulling beam combiner, shows notable advantages for some important performance metrics for a…

Instrumentation and Methods for Astrophysics · Physics 2023-02-08 Jonah T. Hansen , Michael J. Ireland , Romain Laugier , the LIFE collaboration

We consider the reconstruction of a two-dimensional discrete image from a set of tomographic measurements corresponding to the Radon projection. Assuming that the image has a structure where neighbouring pixels have a larger probability to…

Numerical Analysis · Computer Science 2013-04-04 Emmanuelle Gouillart , Florent Krzakala , Marc Mezard , Lenka Zdeborová

Mesoscale structures can often be described as fractional dimensional across a wide range of scales. We consider a $\gamma$ dimensional measure embedded in an $N$ dimensional space and discuss how to determine its dimension, both in $N$…

High Energy Astrophysical Phenomena · Physics 2025-12-09 Svitlana Mayboroda , David N Spergel

It is well-known that non-linear approximation has an advantage over linear schemes in the sense that it provides comparable approximation rates to those of the linear schemes, but to a larger class of approximands. This was established for…

Classical Analysis and ODEs · Mathematics 2010-04-28 Thomas Hangelbroek , Amos Ron

This paper proposes a polyline shaped array based system scheme, associated with mechanical scanning along the perpendicular direction of the array, for near-field millimeter-wave (MMW) imaging. Each section of the polyline is a chord of a…

Signal Processing · Electrical Eng. & Systems 2021-09-08 Shuoguang Wang , Shiyong Li , Guoqiang Zhao , Houjun Sun

Antenna array calibration is necessary to maintain the high fidelity of beam patterns across a wide range of advanced antenna systems and to ensure channel reciprocity in time division duplexing schemes. Despite the continuous development…

Signal Processing · Electrical Eng. & Systems 2023-05-26 Sergey S. Tambovskiy , Gábor Fodor , Hugo M. Tullberg

Two-wavelength adaptive optics (AO) systems sense wavefront errors using a beacon at one wavelength, while correcting for subsequent imaging or beam projection at another. Although most AO systems operate in this manner, the relevant AO…

Optics · Physics 2025-09-17 Milo Hyde , Mark Spencer , Matt Kalensky

In order to meet the theoretically achievable imaging performance, calibration of modern radio interferometers is a mandatory challenge, especially at low frequencies. In this perspective, we propose a novel parallel iterative…

Instrumentation and Methods for Astrophysics · Physics 2016-09-09 Martin Brossard , Mohammed Nabil El Korso , Marius Pesavento , Rémy Boyer , Pascal Larzabal , Stefan J. Wijnholds

Radio interferometers suffer from the problem of missing information in their data, due to the gaps between the antennas. This results in artifacts, such as bright rings around sources, in the images obtained. Multiple deconvolution…

Instrumentation and Methods for Astrophysics · Physics 2021-03-24 Michelle Lochner , Bruce A. Bassett , Martin Kunz , Iniyan Natarajan , Nadeem Oozeer , Oleg Smirnov , Jon Zwart

Wave-mechanical effects in gravitational lensing have long been predicted, and with the discovery of populations of compact transients such as gravitational wave events and fast radio bursts, may soon be observed. We present an observer's…

High Energy Astrophysical Phenomena · Physics 2023-04-04 Calvin Leung , Dylan Jow , Prasenjit Saha , Liang Dai , Masamune Oguri , Léon V. E. Koopmans

Focal plane arrays of bolometers are increasingly employed in astronomy at far--infrared to millimetre wavelengths. The focal plane fields and the detectors are both partially coherent in these systems, but no account has previously been…

Astrophysics · Physics 2009-11-13 George Saklatvala , Michael P. Hobson , Stafford Withington

Wireless channel propagation parameter estimation forms the foundation of channel sounding, estimation, modeling, and sensing. This paper introduces a Deep Learning approach for joint delay- and Doppler estimation from frequency and time…

Signal Processing · Electrical Eng. & Systems 2025-10-22 Steffen Schieler , Sebastian Semper , Reiner Thomä