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Quantitative helio- and asteroseismology require very precise measurements of the frequencies, amplitudes, and lifetimes of the global modes of stellar oscillation. It is common knowledge that the precision of these measurements depends on…

Astrophysics · Physics 2009-11-13 Thorsten Stahn , Laurent Gizon

We investigate the viability of using machine-learning techniques for estimating user-channel features at a large-array base station (BS). In the scenario we consider, user-pilot broadcasts are observed and processed by the BS to extract…

Signal Processing · Electrical Eng. & Systems 2018-02-02 Shiva Navabi , Chenwei Wang , Ozgun Y. Bursalioglu , Haralabos Papadopoulos

One of the key issues facing Direct-to-Cellular (D2C) satellite communication systems is ionospheric scintillation on the uplink and downlink, which can significantly degrade link quality. This work investigates the spatial and temporal…

Signal Processing · Electrical Eng. & Systems 2026-02-20 Abdollah Masoud Darya , Muhammad Mubasshir Shaikh

This paper presents an observing methodology for calibrated measurements of radio interference levels and compare these with threshold interference limits that have been established for interference entering the bands allocated to the Radio…

Instrumentation and Methods for Astrophysics · Physics 2023-03-01 Willem A. Baan , Axel Jessner , Jaap Steenge

Modern radio interferometers sensitive to low frequencies will make use of wide-band detectors. For such wide bandwidths, dispersive atmospheric effects introduce variations in the fringe delay which change through the band of the…

Instrumentation and Methods for Astrophysics · Physics 2011-01-25 I. Marti-Vidal

Accurate modeling of infrasound transmission loss is essential for evaluating the performance of the International Monitoring System, enabling the effective design and maintenance of infrasound stations to support compliance of the…

Continuum emission from a solar flare observed with the Extreme ultraviolet Imaging Spectrometer (EIS) on board the Hinode satellite is used to obtain the radiometric calibration of the instrument. The flare had a GOES class of M8, and…

Solar and Stellar Astrophysics · Physics 2026-05-07 Peter R. Young , Biswajit Mondal

Context. The increased detection rate of Fast Radio Bursts (FRBs) makes it likely to get samples of sizes $\mathcal{O}(10^2)$ to $\mathcal{O}(10^3)$ in the near future. Because of their extragalactic origin can help us in understanding the…

High Energy Astrophysical Phenomena · Physics 2021-05-28 Albert Wai Kit Lau , Ayan Mitra , Mehdi Shafiee , George Smoot

Polarised radio synchrotron emission from interstellar, intracluster and intergalactic magnetic fields is affected by frequency-dependent Faraday depolarisation. The maximum polarised intensity depends on the physical properties of the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Tigran G. Arshakian , Rainer Beck

Ground-based optical microlensing surveys have provided tantalising, if inconclusive, evidence for a significant population of free-floating planets (FFPs). Both ground and space-based facilities are being used and developed which will be…

Earth and Planetary Astrophysics · Physics 2016-11-02 M. Ban , E. Kerins , A. C. Robin

Radio frequency (RF) communications offer reliable but low data rates and energy-inefficient satellite links, while free-space optical (FSO) promises high bandwidth but struggles with disturbances imposed by atmospheric effects. A hybrid…

Systems and Control · Electrical Eng. & Systems 2024-10-24 Mostafa Ibrahim , Arsalan Ahmad , Sabit Ekin , Peter LoPresti , Serhat Altunc , Obadiah Kegege , John F. O'Hara

Guided ultrasonic wave localization uses spatially distributed multistatic sensor arrays and generalized beamforming strategies to detect and locate damage across a structure. The propagation channel is often very complex. Methods can…

Signal Processing · Electrical Eng. & Systems 2024-10-30 Ishan D. Khurjekar , Joel B. Harley

As wireless systems evolve toward higher frequencies and extremely large antenna arrays, near-field (NF) propagation becomes increasingly dominant. Unlike far-field (FF) communication, which relies on a planar-wavefront model and is limited…

Signal Processing · Electrical Eng. & Systems 2025-12-22 Lin Chen , Ahmed Elzanaty , Mustafa A. Kishk , Ying-Jun Angela Zhang

Faraday tomography is thought to be a powerful tool to explore cosmic magnetic field. Broadband radio polarimetric data is essential to ensure the quality of Faraday tomography, but such data is not easy to obtain because of radio frequency…

Instrumentation and Methods for Astrophysics · Physics 2018-12-05 Takuya Akahori , Shinsuke Ideguchi , Takahiro Aoki , Kazuhiro Takefuji , Hideki Ujihara , Keitaro Takahashi

This work presents the study of the variability of foF2 and hmF2 at a low latitude station in South America (Tucum\'an, 26.9{\deg}S, 294.6{\deg}E; magnetic latitude 15.5{\deg}S, Argentina). Ground based ionosonde measurements obtained…

Atmospheric and Oceanic Physics · Physics 2020-04-27 Gilda González , Jorgelina López

We consider the issue of hemispherical power asymmetry in the three-year WMAP data, adopting a previously introduced modulation framework. Computing both frequentist probabilities and Bayesian evidences, we find that the model consisiting…

Astrophysics · Physics 2009-11-13 H. K. Eriksen , A. J. Banday , K. M. Gorski , F. K. Hansen , P. B. Lilje

Refraction and diffraction of incoming radio waves by the ionosphere induce time variability in the angular positions, peak amplitudes and shapes of radio sources, potentially complicating the automated cross-matching and identification of…

In helioseismology, there is a well-known offset between observed and computed oscillation frequencies. This offset is known to arise from improper modeling of the near-surface layers of the Sun, and a similar effect must occur for models…

Astrophysics · Physics 2009-11-13 Hans Kjeldsen , Timothy R. Bedding , Joergen Christensen-Dalsgaard

We present a study of scintillation induced by the mid-latitude ionosphere. By implementing methods currently used in Interplanetary Scintillation studies to measure amplitude scintillation at low frequencies, we have proven it is possible…

Instrumentation and Methods for Astrophysics · Physics 2022-09-14 A. Waszewski , J. Morgan , C. H. Jordan

Spatiotemporal datasets, which consist of spatially-referenced time series, are ubiquitous in diverse applications, such as air pollution monitoring, disease tracking, and cloud-demand forecasting. As the scale of modern datasets increases,…

Machine Learning · Computer Science 2024-11-28 Feras Saad , Jacob Burnim , Colin Carroll , Brian Patton , Urs Köster , Rif A. Saurous , Matthew Hoffman