5,640 research outputs found

    On the Estimation of Nonrandom Signal Coefficients from Jittered Samples

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    This paper examines the problem of estimating the parameters of a bandlimited signal from samples corrupted by random jitter (timing noise) and additive iid Gaussian noise, where the signal lies in the span of a finite basis. For the presented classical estimation problem, the Cramer-Rao lower bound (CRB) is computed, and an Expectation-Maximization (EM) algorithm approximating the maximum likelihood (ML) estimator is developed. Simulations are performed to study the convergence properties of the EM algorithm and compare the performance both against the CRB and a basic linear estimator. These simulations demonstrate that by post-processing the jittered samples with the proposed EM algorithm, greater jitter can be tolerated, potentially reducing on-chip ADC power consumption substantially.Comment: 11 pages, 8 figure

    The political economy of regionalism

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    We examine the incentives of regions in a country to unite or to separate. We find that smaller regions have greater incentives to unite, relative to larger regions. We show, however, that on the whole, majority voting on separation and union generates excessive incentives to separate. This leads us to examine the scope of alternative political insititutions and rules in overcoming the potential inefficciency. Our paper also provides a wide range of examples to illustrate the different instituions used in actual practice to resolve such problems.voting;referendum;secession;union

    A stable Algebraic Spin Liquid in a Hubbard model

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    We show the existence of a stable Algebraic Spin Liquid (ASL) phase in a Hubbard model defined on a honeycomb lattice with spin-dependent hopping that breaks time-reversal symmetry. The effective spin model is the Kitaev model for large on-site repulsion. The gaplessness of the emergent Majorana fermions is protected by the time reversal (TR) invariance of this model. We prove that the effective spin model is TR invariant in the entire Mott phase thus ensuring the stability of the ASL. The model can be physically realized in cold atom systems and we propose experimental signals of the ASL.Comment: Published in PR

    The political economy of regionalism

    Get PDF
    We examine the incentives of regions in a country to unite or to separate. We find that smaller regions have greater incentives to unite, relative to larger regions. We show, however, that on the whole, majority voting on separation and union generates excessive incentives to separate. This leads us to examine the scope of alternative political insititutions and rules in overcoming the potential inefficciency. Our paper also provides a wide range of examples to illustrate the different instituions used in actual practice to resolve such problems
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