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We derive the distribution of flux density of a compact source exhibiting strong diffractive scintillation. Our treatment accounts for arbitrary spectral averaging, spatially-extended source emission, and the possibility of intrinsic…

Instrumentation and Methods for Astrophysics · Physics 2012-08-09 Michael D. Johnson , Carl R. Gwinn

A new segmented compressed sampling method for analog-to-information conversion (AIC) is proposed. An analog signal measured by a number of parallel branches of mixers and integrators (BMIs), each characterized by a specific random sampling…

Information Theory · Computer Science 2015-05-18 Omid Taheri , Sergiy A. Vorobyov

We have developed an algorithm that, starting from the observed properties of the X-ray spectrum and fast variability of an X-ray binary allows the production of synthetic data reproducing observables such as power density spectra and time…

High Energy Astrophysical Phenomena · Physics 2015-05-19 Y. X. Wu , T. M. Belloni , L. Stella

Measurements of low-order p modes and gravity modes are perturbed by the solar convective background. Such perturbation increases below 2mHz for intensity measurements and 1mHz for velocity measurements. While the low-degree modes have…

Astrophysics · Physics 2008-10-10 R. A. Garcia , S. Mathur , I. Gonzalez Hernandez , A. Jimenez

When inverting solar spectra, image degradation effects that are present in the data are usually approximated or not considered. We develop a data reduction method that takes these issues into account and minimizes the resulting errors. By…

Instrumentation and Methods for Astrophysics · Physics 2015-06-11 M. van Noort

Digital camera pixels measure image intensities by converting incident light energy into an analog electrical current, and then digitizing it into a fixed-width binary representation. This direct measurement method, while conceptually…

Computer Vision and Pattern Recognition · Computer Science 2021-04-13 Atul Ingle , Trevor Seets , Mauro Buttafava , Shantanu Gupta , Alberto Tosi , Mohit Gupta , Andreas Velten

Speckle patterns are used in a broad range of applications including microscopy, imaging, and light-matter interactions. Tailoring speckles' statistics can dramatically enhance their performance in applications. We present an experimental…

The main purpose of this article is to alert spectroscopists, particularly those involved in surveys, to the fact that rapidly pulsating sources induce periodic structures in spectra. This would allow the detection of new classes of objects…

High Energy Astrophysical Phenomena · Physics 2010-03-18 Ermanno F. Borra

We study an efficient dynamic blind source separation algorithm of convolutive sound mixtures based on updating statistical information in the frequency domain, andminimizing the support of time domain demixing filters by a weighted least…

Statistics Theory · Mathematics 2007-05-23 Jie Liu , Jack Xin , Yingyong Qi

This paper investigates the problem of dynamical sampling for graph signals influenced by a constant source term. We consider signals evolving over time according to a linear dynamical system on a graph, where both the initial state and the…

Numerical Analysis · Mathematics 2025-09-23 Le Gong , Longxiu Huang

Vibrational spectroscopy is a cornerstone technique for molecular characterization and offers an ideal target for the computational investigation of molecular materials. Building on previous comprehensive assessments of efficient methods…

We study imaging with an array of sensors that probes a medium with single frequency electromagnetic waves and records the scattered electric field. The medium is known and homogenous except for some small and penetrable inclusions. The…

Analysis of PDEs · Mathematics 2016-09-21 Liliana Borcea , Josselin Garnier

Spectrum sensing is a fundamental operation in cognitive radio environment. It gives information about spectrum availability by scanning the bands. Usually a fixed amount of time is given to scan individual bands. Most of the times,…

Information Theory · Computer Science 2016-06-10 Garimella Rama Murthy , Rhishi Pratap Singh , Samdarshi Abhijeet , Sachin Chaudhary

AX J1910.7+0917 is a still unidentified source discovered with ASCA and observed more recently with IBIS/ISGRI, mainly noticeable for its rather hard spectrum. We analyzed all the public available data on this source, and we took advantage…

High Energy Astrophysical Phenomena · Physics 2011-04-28 L. Pavan , E. Bozzo , C. Ferrigno , C. Ricci , A. Manousakis , R. Walter , L. Stella

In this paper, we propose an efficient technique for estimating individual power spectral density (PSD) components, i.e., PSD of each desired sound source as well as of noise and reverberation, in a multi-source reverberant sound scene with…

Sound · Computer Science 2018-05-17 Abdullah Fahim , Prasanga N. Samarasinghe , Thushara D. Abhayapala

A new instrument for spot profile analysis of electron diffraction - SPA-LEED - has been set up. The instrument works either with a transparent phosphor screen for visual inspection of the pattern or in its main mode with a channeltron for…

Materials Science · Physics 2015-01-30 U. Scheithauer , G. Meyer , M. Henzler

This paper presents a novel approach for estimating the modes of an observed non-stationary mixture signal. A link is first established between the short-time Fourier transform and the sparse sampling theory, where the observations are…

Numerical Analysis · Mathematics 2022-12-23 Quentin Legros , Dominique Fourer

Our collaboration is responsible for the study of a sample of 72 low mass X-ray binaries (LMXRB) using the INTEGRAL Core Programme data. In this paper we describe the monitoring programme we have started and the current variability and…

We study efficiency of intensity-based dynamic speckle method for characterization of dynamic events which occur at variable rate in time within the temporal averaging interval. We checked ability of the method to describe the speed…

We study the noise of the intensity variance and of the intensity correlation and structure functions measured in light scattering from a random medium in the case when these quantities are obtained by averaging over a finite number N of…