39,383 research outputs found
Learning from networked examples
Many machine learning algorithms are based on the assumption that training
examples are drawn independently. However, this assumption does not hold
anymore when learning from a networked sample because two or more training
examples may share some common objects, and hence share the features of these
shared objects. We show that the classic approach of ignoring this problem
potentially can have a harmful effect on the accuracy of statistics, and then
consider alternatives. One of these is to only use independent examples,
discarding other information. However, this is clearly suboptimal. We analyze
sample error bounds in this networked setting, providing significantly improved
results. An important component of our approach is formed by efficient sample
weighting schemes, which leads to novel concentration inequalities
Fractional quantum Hall effect of topological surface states under a strong tilted magnetic field
The fractional quantum Hall effect (FQHE) of topological surface-state
particles under a tilted strong magnetic field is theoretically studied by
using the exact diagonalization method. The Haldane's pseudopotentials for the
Coulomb interaction are analytically obtained. The results show that by
increasing the in-plane component of the tilted magnetic field, the FQHE state
at =0 Landau level (LL) becomes more stable, while the stabilities of
= LLs become weaker. Moreover, we find that the excitation gaps of the
FQHE states increase as the tilt angle is increased.Comment: 4.2 pages, 4 figure
Thermal Conductance for Single Wall Carbon Nanotubes
We report a theoretical analysis of the phonon thermal conductance, \kappa
(T), for single wall carbon nanotubes (SWCN). In a range of low temperatues up
to 100K, \kappa (T) of perfect SWCN is found to increase with temperature,
approximately, in a parabolic fashion. This is qualitatively consistent with
recent experimental measurements where the tube-tube interactions are
negligibly weak. When the carbon-carbon bond length is slightly varied, \kappa
(T) is found to be qualitatively unaltered which implies that the anharmonic
effect does not change the qualitative behavior of \kappa (T).Comment: Revtex, 4 figure
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