4,983 research outputs found
Generalized survival in equilibrium step fluctuations
We investigate the dynamics of a generalized survival probability
defined with respect to an arbitrary reference level (rather than the
average) in equilibrium step fluctuations. The exponential decay at large time
scales of the generalized survival probability is numerically analyzed.
is shown to exhibit simple scaling behavior as a function of
system-size , sampling time , and the reference level . The
generalized survival time scale, , associated with is shown
to decay exponentially as a function of .Comment: 4 pages, 2 figure
Out-of-equilibrium critical dynamics at surfaces: Cluster dissolution and non-algebraic correlations
We study nonequilibrium dynamical properties at a free surface after the
system is quenched from the high-temperature phase into the critical point. We
show that if the spatial surface correlations decay sufficiently rapidly the
surface magnetization and/or the surface manifold autocorrelations has a
qualitatively different universal short time behavior than the same quantities
in the bulk. At a free surface cluster dissolution may take place instead of
domain growth yielding stationary dynamical correlations that decay in a
stretched exponential form. This phenomenon takes place in the
three-dimensional Ising model and should be observable in real ferromagnets.Comment: 4 pages, 4 figure
First measurements of the flux integral with the NIST-4 watt balance
In early 2014, construction of a new watt balance, named NIST-4, has started
at the National Institute of Standards and Technology (NIST). In a watt
balance, the gravitational force of an unknown mass is compensated by an
electromagnetic force produced by a coil in a magnet system. The
electromagnetic force depends on the current in the coil and the magnetic flux
integral. Most watt balances feature an additional calibration mode, referred
to as velocity mode, which allows one to measure the magnetic flux integral to
high precision. In this article we describe first measurements of the flux
integral in the new watt balance. We introduce measurement and data analysis
techniques to assess the quality of the measurements and the adverse effects of
vibrations on the instrument.Comment: 7 pages, 8 figures, accepted for publication in IEEE Trans. Instrum.
Meas. This Journal can be found online at
http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=1
Integral Human Pose Regression
State-of-the-art human pose estimation methods are based on heat map
representation. In spite of the good performance, the representation has a few
issues in nature, such as not differentiable and quantization error. This work
shows that a simple integral operation relates and unifies the heat map
representation and joint regression, thus avoiding the above issues. It is
differentiable, efficient, and compatible with any heat map based methods. Its
effectiveness is convincingly validated via comprehensive ablation experiments
under various settings, specifically on 3D pose estimation, for the first time
Persistence of Manifolds in Nonequilibrium Critical Dynamics
We study the persistence P(t) of the magnetization of a d' dimensional
manifold (i.e., the probability that the manifold magnetization does not flip
up to time t, starting from a random initial condition) in a d-dimensional spin
system at its critical point. We show analytically that there are three
distinct late time decay forms for P(t) : exponential, stretched exponential
and power law, depending on a single parameter \zeta=(D-2+\eta)/z where D=d-d'
and \eta, z are standard critical exponents. In particular, our theory predicts
that the persistence of a line magnetization decays as a power law in the d=2
Ising model at its critical point. For the d=3 critical Ising model, the
persistence of the plane magnetization decays as a power law, while that of a
line magnetization decays as a stretched exponential. Numerical results are
consistent with these analytical predictions.Comment: 4 pages revtex, 1 eps figure include
Reflectionless analytic difference operators I. algebraic framework
We introduce and study a class of analytic difference operators admitting
reflectionless eigenfunctions. Our construction of the class is patterned after
the Inverse Scattering Transform for the reflectionless self-adjoint
Schr\"odinger and Jacobi operators corresponding to KdV and Toda lattice
solitons
Exploiting temporal information for 3D pose estimation
In this work, we address the problem of 3D human pose estimation from a
sequence of 2D human poses. Although the recent success of deep networks has
led many state-of-the-art methods for 3D pose estimation to train deep networks
end-to-end to predict from images directly, the top-performing approaches have
shown the effectiveness of dividing the task of 3D pose estimation into two
steps: using a state-of-the-art 2D pose estimator to estimate the 2D pose from
images and then mapping them into 3D space. They also showed that a
low-dimensional representation like 2D locations of a set of joints can be
discriminative enough to estimate 3D pose with high accuracy. However,
estimation of 3D pose for individual frames leads to temporally incoherent
estimates due to independent error in each frame causing jitter. Therefore, in
this work we utilize the temporal information across a sequence of 2D joint
locations to estimate a sequence of 3D poses. We designed a
sequence-to-sequence network composed of layer-normalized LSTM units with
shortcut connections connecting the input to the output on the decoder side and
imposed temporal smoothness constraint during training. We found that the
knowledge of temporal consistency improves the best reported result on
Human3.6M dataset by approximately and helps our network to recover
temporally consistent 3D poses over a sequence of images even when the 2D pose
detector fails
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