8,348 research outputs found

    Faint flux performance of an EMCCD

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    Thorough numerical simulations were run to test the performance of three processing methods of the data coming out from an electron multiplying charge coupled device (EMCCD), or low light level charge coupled device (L3CCD), operated at high gain, under real operating conditions. The effect of read-out noise and spurious charges is tested under various low flux conditions (0.001 event/pixel/frame < f < 20 events/pixel/frame). Moreover, a method for finding the value of the gain applied by the EMCCD amplification register is also developed. It allows one to determine the gain value to an accuracy of a fraction of a percent from dark frames alone.Comment: 9 pages, 6 figures, to appear in SPIE conference proceedings vol 6276, "High Energy, Optical & Infrared Detectors for Astronomy II" Orlando FL USA, 24-31 May 2006. Code is available at http://www.astro.umontreal.ca/~odaigle/emcc

    Verification of Timed Automata Using Rewrite Rules and Strategies

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    ELAN is a powerful language and environment for specifying and prototyping deduction systems in a language based on rewrite rules controlled by strategies. Timed automata is a class of continuous real-time models of reactive systems for which efficient model-checking algorithms have been devised. In this paper, we show that these algorithms can very easily be prototyped in the ELAN system. This paper argues through this example that rewriting based systems relying on rules and strategies are a good framework to prototype, study and test rather efficiently symbolic model-checking algorithms, i.e. algorithms which involve combination of graph exploration rules, deduction rules, constraint solving techniques and decision procedures

    Synthetic aperture radar demonstration kit for signal processing education

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    A Synthetic Aperture Radar scale model has been developed to improve signal processing teaching. Based on low frequency ultrasound transmission, it is a low cost demonstration kit. The overall software is directly running on Matlab® and allows easy and realtime modifications. This educational tool can be used to illuminate a scene using different waveforms, and then see the effects on the formed image. It can also be used in a more advanced way to test different signal processing in order to improve image focusing or to reduce computation burden

    7. Comme des bĂŞtes. Essay Review

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    Essay Review: Recension de Pierre Serna, Comme des bêtes. Histoire politique de l’animal en Révolution (1750-1848), Paris: Fayard, 2017

    Harmonic analysis of the Ha velocity field of NGC 4254

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    The ionized gas kinematics of the Virgo Cluster galaxy NGC 4254 (Messier 99) is analyzed by an harmonic decomposition of the velocity field into Fourier coefficients. The aims of this study are to measure the kinematical asymmetries of Virgo cluster galaxies and to connect them to the environment. The analysis reveals significant m=1,2,4m=1,2,4 terms which origins are discussed.Comment: 3 pages, 2 figures, to appear in "Science Perspectives for 3D Spectroscopy", ESO Astrophysics Symposia, M. Kissler-Patig, M.M. Roth & J.R. Walsh ed
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