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Diverse applications in photonics and microwave engineering require a means of measurement of the instantaneous frequency of a signal. A photonic implementation typically applies an interferometer equipped with three or more output ports to…

We provide here a framework to analyze the phase transition phenomenon of slice inverse regression (SIR), a supervised dimension reduction technique introduced by \cite{Li:1991}. Under mild conditions, the asymptotic ratio $\rho= \lim p/n$…

Statistics Theory · Mathematics 2016-11-22 Qian Lin , Zhigen Zhao , Jun S. Liu

Multi-frequency interferometry (MFI) is well known as an accurate phase-based measurement scheme. The paper reveals the inherent relationship of the unambiguous measurement range (UMR), the outlier probability, the MSE performance with the…

Information Theory · Computer Science 2012-10-09 Li Wei , Wangdong Qi

As radio telescopes become more sensitive, the damaging effects of radio frequency interference (RFI) become more apparent. Near radio telescope arrays, RFI sources are often easily removed or replaced; the challenge lies in identifying…

Instrumentation and Methods for Astrophysics · Physics 2018-08-01 Daniel Czech , Amit Mishra , Michael Inggs

We describe a "spatio-spectral" deconvolution algorithm for wide-band imaging in radio interferometry. In contrast with the existing multi-frequency reconstruction algorithms, the proposed method does not rely on a model of the…

Instrumentation and Methods for Astrophysics · Physics 2016-03-01 André Ferrari , Jérémy Deguignet , Chiara Ferrari , David Mary , Antony Schutz , Oleg Smirnov

Radio interferometers consisting of identical antennas arranged on a regular lattice permit fast Fourier transform beamforming, which reduces the correlation cost from $\mathcal{O}(n^2)$ in the number of antennas to $\mathcal{O}(n\log n)$.…

Instrumentation and Methods for Astrophysics · Physics 2019-05-20 Kiyoshi W. Masui , J. Richard Shaw , Cherry Ng , Kendrick M. Smith , Keith Vanderlinde , Adiv Paradise

Measurement of interferometric parameters values is affected by phase disturbance due especially to atmospheric turbulences. Algorithms of fringe sensing, aimed at fringe parameters identification, are based on interferometric models that…

Instrumentation and Methods for Astrophysics · Physics 2009-08-27 Bonino Donata

LOFAR (Low Frequency Array) is an innovative radio telescope optimized for the frequency range 30-240 MHz. The telescope is realized as a phased aperture array without any moving parts. Digital beam forming allows the telescope to point to…

Radio Interferometry is an essential method for astronomical observations. Self-calibration techniques have increased the quality of the radio astronomical observations (and hence the science) by orders of magnitude. Recently, there is a…

Astrophysics · Physics 2008-11-03 Sarod Yatawatta , Saleem Zaroubi , Ger de Bruyn , Leon Koopmans , Jan Noordam

Image identification is one of the most challenging tasks in different areas of computer vision. Scale-invariant feature transform is an algorithm to detect and describe local features in images to further use them as an image matching…

Computer Vision and Pattern Recognition · Computer Science 2018-03-15 Ebrahim Karami , Mohamed Shehata , Andrew Smith

Over the last decades, radio detection of air showers has been established as a promising detection technique for ultrahigh-energy cosmic rays and neutrinos. Very large or dense antenna arrays are necessary to be proficient at collecting…

Instrumentation and Methods for Astrophysics · Physics 2018-11-28 Anne Zilles , Olivier Martineau-Huynh , Kumiko Kotera , Matias Tueros , Krijn de Vries , Washington Carvalho , Valentin Niess

Time-resolved optical filtering (TROF) measures the spectrogram or sonogram by a fast photodiode followed a tunable narrowband optical filter. For periodic signal and to match the sonogram, numerical TROF algorithm is used to find the…

Optics · Physics 2013-01-15 KeangPo Ho , Hsi-Cheng Wang , Hau-Kai Chen , Cheng-Chen Wu

A novel coding scheme applicable in networks with single antenna nodes is proposed. This scheme converts a single antenna system to an equivalent Multiple Input Multiple Output (MIMO) system with fractional dimensions. Interference can be…

Information Theory · Computer Science 2009-08-12 Abolfazl S. Motahari , Shahab Oveis Gharan , Amir K. Khandani

Radio Frequency Interference (RFI) is a growing concern in the radio astronomy community. Single-dish telescopes are particularly susceptible to RFI. Several methods have been developed to cope with RF-polluted environments, based on…

Instrumentation and Methods for Astrophysics · Physics 2018-05-23 R. Finger , F. Curotto , R. Fuentes , R. Duan , L. Bronfman , D. Li

Mobile communication channels are often modeled as linear time-varying filters or, equivalently, as time-frequency integral operators with finite support in time and frequency. Such a characterization inherently assumes the signals are…

Information Theory · Computer Science 2007-07-16 Scott T. Rickard , Radu V. Balan , H. Vincent Poor , Sergio Verdu

Over the last years, radio detection has matured to become a competitive method for the detection of air showers. Arrays of thousands of antennas are now envisioned for the detection of cosmic rays of ultra high energy or neutrinos of…

Radio Tomographic Imaging (RTI) is a phaseless imaging approach that can provide shape reconstruction and localization of objects using received signal strength (RSS) measurements. RSS measurements can be straightforwardly obtained from…

Applied Physics · Physics 2023-11-17 Amartansh Dubey , Zan Li , Ross Murch

Detecting the redshifted global 21-cm signal from the cosmic dawn (CD) remains a major challenge due to strong terrestrial Radio Frequency Interference (RFI), particularly dominated by Frequency Modulation (FM) transmissions in the 88-110…

Instrumentation and Methods for Astrophysics · Physics 2026-05-22 Yogen Pranesh , Mayuri Sathyanarayana Rao , Saurabh Singh

Calibration of radio interferometric observations becomes increasingly difficult towards lower frequencies. Below ~300 MHz, spatially variant refractions and propagation delays of radio waves traveling through the ionosphere cause phase…

Instrumentation and Methods for Astrophysics · Physics 2015-05-13 H. T. Intema , S. van der Tol , W. D. Cotton , A. S. Cohen , I. M. van Bemmel , H. J. A. Rottgering

The next generation of adaptive optics (AO) systems will require tomographic reconstruction techniques to map the optical refractive index fluctuations, generated by the atmospheric turbulence, along the line of sight to the astronomical…

Instrumentation and Methods for Astrophysics · Physics 2014-01-07 H. W. Shepherd , J. Osborn , R. W. Wilson , T. Butterley , R. Avila , V. S. Dhillon , T. J. Morris