22,412 research outputs found

    Mental Health as Viewed by Medics and Mystics

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    The moderate resolution imaging spectrometer: An EOS facility instrument candidate for application of data compression methods

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    The Moderate Resolution Imaging Spectrometer (MODIS) observing facility will operate on the Earth Observing System (EOS) in the late 1990's. It is estimated that this observing facility will produce over 200 gigabytes of data per day requiring a storage capability of just over 300 gigabytes per day. Archiving, browsing, and distributing the data associated with MODIS represents a rich opportunity for testing and applying both lossless and lossy data compression methods

    The Reliability Function of Lossy Source-Channel Coding of Variable-Length Codes with Feedback

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    We consider transmission of discrete memoryless sources (DMSes) across discrete memoryless channels (DMCs) using variable-length lossy source-channel codes with feedback. The reliability function (optimum error exponent) is shown to be equal to max{0,B(1R(D)/C)},\max\{0, B(1-R(D)/C)\}, where R(D)R(D) is the rate-distortion function of the source, BB is the maximum relative entropy between output distributions of the DMC, and CC is the Shannon capacity of the channel. We show that, in this setting and in this asymptotic regime, separate source-channel coding is, in fact, optimal.Comment: Accepted to IEEE Transactions on Information Theory in Apr. 201

    Measurement of spectral functions of ultracold atoms in disordered potentials

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    We report on the measurement of the spectral functions of noninteracting ultracold atoms in a three-dimensional disordered potential resulting from an optical speckle field. Varying the disorder strength by 2 orders of magnitude, we observe the crossover from the "quantum" perturbative regime of low disorder to the "classical" regime at higher disorder strength, and find an excellent agreement with numerical simulations. The method relies on the use of state-dependent disorder and the controlled transfer of atoms to create well-defined energy states. This opens new avenues for experimental investigations of three-dimensional Anderson localization
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