2,774 research outputs found
Single step optimal block matched motion estimation with motion vectors having arbitrary pixel precisions
This paper proposes a non-linear block matched motion model with motion vectors having arbitrary pixel precisions. The optimal motion vector which minimizes the mean square error is solved analytically in a single step. Our proposed algorithm can be regarded as a generalization of conventional half pixel search algorithms and quarter pixel search algorithms because our proposed algorithm could achieve motion vectors with arbitrary pixel precisions. Also, the computational effort of our proposed algorithm is lower than that of conventional quarter pixel search algorithms because our proposed algorithm could achieve motion vectors in a single step
Empirical study on clique-degree distribution of networks
The community structure and motif-modular-network hierarchy are of great
importance for understanding the relationship between structures and functions.
In this paper, we investigate the distribution of clique-degree, which is an
extension of degree and can be used to measure the density of cliques in
networks. The empirical studies indicate the extensive existence of power-law
clique-degree distributions in various real networks, and the power-law
exponent decreases with the increasing of clique size.Comment: 9 figures, 4 page
Statistical significance of rich-club phenomena in complex networks
We propose that the rich-club phenomena in complex networks should be defined
in the spirit of bootstrapping, in which a null model is adopted to assess the
statistical significance of the rich-club detected. Our method can be served as
a definition of rich-club phenomenon and is applied to analyzing three real
networks and three model networks. The results improve significantly compared
with previously reported results. We report a dilemma with an exceptional
example, showing that there does not exist an omnipotent definition for the
rich-club phenomenon.Comment: 3 Revtex pages + 5 figure
TeV-scale Type-II Seesaw Models and Possible Collider Signatures
A natural extension of the standard model to accommodate massive neutrinos is
to introduce one Higgs triplet and three right-handed Majorana neutrinos,
leading to a 6 \times6 neutrino mass matrix. We show that three light Majorana
neutrinos (i.e., the mass eigenstates of \nu_e, \nu_\mu and \nu_\tau) are
exactly massless, if and only if M_L = M_D M^{-1}_R M^T_D exactly holds in this
seesaw model. We propose three simple Type-II seesaw scenarios with broken A_4
\times U(1)_X flavor symmetry to interpret the observed neutrino mass spectrum
and neutrino mixing pattern. Such a TeV-scale neutrino model can be tested in
two complementary ways: (1) searching for possible collider signatures of
lepton number violation induced by the right-handed Majorana neutrinos and
doubly-charged Higgs particles; and (2) searching for possible consequences of
unitarity violation of the 3\times 3 neutrino mixing matrix in the future
long-baseline neutrino oscillation experiments.Comment: 4 pages. Talk given by Wei Chao at the 4th International Conference
on Flavor Physics, 24-28 September 2007, Beijing (to appear in the
proceedings
Non-Gaussian Features of Transmitted Flux of QSO's Ly Absorption: Intermittent Exponent
We calculate the structure function and intermittent exponent of the 1.) Keck
data, which consists of 29 high resolution, high signal to noise ratio (S/N)
QSO Ly absorption spectra, and 2.)the Ly forest simulation
samples produced via the pseudo hydro scheme for the low density cold dark
matter (LCDM) model and warm dark matter (WDM) model with particle mass
and 1000 eV. These two measures detect not only
non-gaussianities, but also the type of non-gaussianty in the the field. We
find that, 1.) the structure functions of the simulation samples are
significantly larger than that of Keck data on scales less than about 100
h kpc, 2.) the intermittent exponent of the simulation samples is more
negative than that of Keck data on all redshifts considered, 3.) the
order-dependence of the structure functions of simulation samples are closer to
the intermittency of hierarchical clustering on all scales, while the Keck data
are closer to a lognormal field on small scales. These differences are
independent of noise and show that the intermittent evolution modeled by the
pseudo-hydro simulation is substantially different from observations, even
though they are in good agreement in terms of second and lower order
statistics. (Abridged)Comment: 17 pages, 13 figures. Accepted by Ap
Experimental Violation of Bell Inequality beyond Cirel'son's Bound
The correlations between two qubits belonging to a three-qubit system can
violate the Clauser-Horne-Shimony-Holt-Bell inequality beyond Cirel'son's bound
[A. Cabello, Phys. Rev. Lett. 88, 060403 (2002)]. We experimentally demonstrate
such a violation by 7 standard deviations by using a three-photon
polarization-entangled Greenberger-Horne-Zeilinger state produced by Type-II
spontaneous parametric down-conversion. In addition, using part of our results,
we obtain a violation of the Mermin inequality by 39 standard deviations.Comment: 4 pages, 3 figure
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