5,640 research outputs found
On the Estimation of Nonrandom Signal Coefficients from Jittered Samples
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
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
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
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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