71,458 research outputs found

    Abnormal oscillation modes in a waning light bridge

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    A sunspot acts as a waveguide in response to the dynamics of the solar interior; the trapped waves and oscillations could reveal its thermal and magnetic structures. We study the oscillations in a sunspot intruded by a light bridge, the details of the oscillations could reveal the fine structure of the magnetic topology. We use the Solar Dynamics Observatory/Atmospheric Imaging Assembly data to analyse the oscillations in the emission intensity of light bridge plasma at different temperatures and investigate their spatial distributions. The extreme ultraviolet emission intensity exhibits two persistent oscillations at five-minute and sub-minute ranges. The spatial distribution of the five-minute oscillation follows the spine of the bridge; whereas the sub-minute oscillations overlap with two flanks of the bridge. Moreover, the sub-minute oscillations are highly correlated in spatial domain, however, the oscillations at the eastern and western flanks are asymmetric with regard to the lag time. In the meanwhile, jet-like activities are only found at the eastern flank. Asymmetries in forms of oscillatory pattern and jet-like activities \textbf{are} found between two flanks of a granular light bridge. Based on our study and recent findings, we propose a new model of twisted magnetic field for a light bridge and its dynamic interactions with the magnetic field of a sunspot.Comment: 5 figures, Accepted version in A&

    Balanced Symmetric Functions over GF(p)GF(p)

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    Under mild conditions on n,pn,p, we give a lower bound on the number of nn-variable balanced symmetric polynomials over finite fields GF(p)GF(p), where pp is a prime number. The existence of nonlinear balanced symmetric polynomials is an immediate corollary of this bound. Furthermore, we conjecture that X(2t,2t+1l1)X(2^t,2^{t+1}l-1) are the only nonlinear balanced elementary symmetric polynomials over GF(2), where X(d,n)=i1<i2<...<idxi1xi2...xidX(d,n)=\sum_{i_1<i_2<...<i_d}x_{i_1} x_{i_2}... x_{i_d}, and we prove various results in support of this conjecture.Comment: 21 page

    Best Fit to the Gluino Mass

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    Assuming that perturbative QCD is the dominant explanation for the narrowness of the vector quarkonia, we perform a χ2\chi^2 minimization analysis of their hadronic decays as a function of two parameters, the mass of the gluino and the value of α3(MZ){\alpha}_3(M_Z). A value below 1 GeV for the gluino mass is strongly preferred. Consequences for SUSY breaking scenarios are discussed.Comment: (15 pages (if not reduced), 7 figures not included), UAHEP92

    N-fold way simulated tempering for pairwise interaction point processes

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    Pairwise interaction point processes with strong interaction are usually difficult to sample. We discuss how Besag lattice processes can be used in a simulated tempering MCMC scheme to help with the simulation of such processes. We show how the N-fold way algorithm can be used to sample the lattice processes efficiently and introduce the N-fold way algorithm into our simulated tempering scheme. To calibrate the simulated tempering scheme we use the Wang-Landau algorithm

    Distributed Stochastic Optimization over Time-Varying Noisy Network

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    This paper is concerned with distributed stochastic multi-agent optimization problem over a class of time-varying network with slowly decreasing communication noise effects. This paper considers the problem in composite optimization setting which is more general in noisy network optimization. It is noteworthy that existing methods for noisy network optimization are Euclidean projection based. We present two related different classes of non-Euclidean methods and investigate their convergence behavior. One is distributed stochastic composite mirror descent type method (DSCMD-N) which provides a more general algorithm framework than former works in this literature. As a counterpart, we also consider a composite dual averaging type method (DSCDA-N) for noisy network optimization. Some main error bounds for DSCMD-N and DSCDA-N are obtained. The trade-off among stepsizes, noise decreasing rates, convergence rates of algorithm is analyzed in detail. To the best of our knowledge, this is the first work to analyze and derive convergence rates of optimization algorithm in noisy network optimization. We show that an optimal rate of O(1/T)O(1/\sqrt{T}) in nonsmooth convex optimization can be obtained for proposed methods under appropriate communication noise condition. Moveover, convergence rates in different orders are comprehensively derived in both expectation convergence and high probability convergence sense.Comment: 27 page

    A Three-Pole Substrate Integrated Waveguide Bandpass Filter Using New Coupling Scheme

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    A novel three-pole substrate integrated waveguide (SIW) bandpass filter (BPF) using new coupling scheme is proposed in this paper. Two high order degenerate modes (TE102 and TE201) of a square SIW cavity and a dominant mode (TE101) of a rectangular SIW cavity are coupled to form a three-pole SIW BPF. The coupling scheme of the structure is given and analyzed. Due to the coupling between two cavities, as well as the coupling between source and load, three transmission zeros are created in the stopband of the filter. The proposed three-pole SIW BPF is designed and fabricated. Good agreement between simulated and measured results verifies the validity of the design methodology well
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