6,802 research outputs found

    Frequency characteristics of aerial scenes with respect to a video imagining system

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    Thesis (M.A.)--Boston UniversityAn overall investigation is made of operating characteristics, theoretical limitations and optimum range values for video communication of aerial scenes. Reasons are given for the selection of a particular receiver and the importance of this type of study is indicated from the A.D.P. crystals' complex A.C. frequency response. The restricted contrast range, due to haze, is noted in evaluating the various video systems

    The Invisible Web: A Quick Overview

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    This article provides a quick overview of recent literature published about the Invisible Web. In particular, this article covers such topics as what is the Invisible Web, weaknesses of popular search engines, types of information found on the Invisible Web, when to use the Invisible Web, search tools and search strategies

    Two-batch liar games on a general bounded channel

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    We consider an extension of the 2-person R\'enyi-Ulam liar game in which lies are governed by a channel CC, a set of allowable lie strings of maximum length kk. Carole selects x∈[n]x\in[n], and Paul makes tt-ary queries to uniquely determine xx. In each of qq rounds, Paul weakly partitions [n]=A0∪>...∪At−1[n]=A_0\cup >... \cup A_{t-1} and asks for aa such that x∈Aax\in A_a. Carole responds with some bb, and if a≠ba\neq b, then xx accumulates a lie (a,b)(a,b). Carole's string of lies for xx must be in the channel CC. Paul wins if he determines xx within qq rounds. We further restrict Paul to ask his questions in two off-line batches. We show that for a range of sizes of the second batch, the maximum size of the search space [n][n] for which Paul can guarantee finding the distinguished element is ∼tq+k/(Ek(C)(qk))\sim t^{q+k}/(E_k(C)\binom{q}{k}) as q→∞q\to\infty, where Ek(C)E_k(C) is the number of lie strings in CC of maximum length kk. This generalizes previous work of Dumitriu and Spencer, and of Ahlswede, Cicalese, and Deppe. We extend Paul's strategy to solve also the pathological liar variant, in a unified manner which gives the existence of asymptotically perfect two-batch adaptive codes for the channel CC.Comment: 26 page

    Simpler Variational Problem for Statistical Equilibria of the 2D Euler Equation and Other Systems with Long Range Interactions

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    The Robert-Sommeria-Miller equilibrium statistical mechanics predicts the final organization of two dimensional flows. This powerful theory is difficult to handle practically, due to the complexity associated with an infinite number of constraints. Several alternative simpler variational problems, based on Casimir's or stream function functionals, have been considered recently. We establish the relations between all these variational problems, justifying the use of simpler formulations.Comment: 5 pages, submited to Physica
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