77,104 research outputs found
Analysis on Metric Space Q
In this paper, we show that the metric space Q is a positively-curved space
(PC-space) in the sense of Alexandrov. We also discuss some issues like metric
tangent cone and exponential map of Q. Then we give a stratification of this
metric space according to the signature of points in Q. Some properties of this
stratification are shown. The second part of this paper is devoted to some
basic analysis on the space Q, like the tensor sum and L-p space, which can be
of independent interest. In the end, we give another definition of derivative
for multiple-valued functions, which is equivalent to the one used by Almgren.
An interesting theorem about regular selection of multiple-valued functions
which preserves the differentiability concludes this paper.Comment: 24 page
Evidence of Different Formation Mechanisms for Hot versus Warm Super-Earths
Using the Kepler planet sample from Buchhave et al. and the statistical
method clarified by Schlaufman, I show that the shorter-period super-Earths
have a different dependence on the host star metallicity from the longer-period
super-Earths, with the transition period being in the period range from 70 to
100 days. The hosts of shorter-period super-Earths are on average more
metal-rich than those of longer-period super-Earths. The existence of such a
transition period cannot be explained by any single theory of super-Earth
formation, suggesting that super-Earths have formed via at least two
mechanisms.Comment: 11 pages, 5 figures; submitted to ApJ Letter
Are valence quarks rotating?
We suggest to compare the deep inelastic scattering structure functions
measured in the unpolarized charged-lepton scattering off a transversely
polarized proton and off a longitudinally polarized proton at larger Bjorken
variable , one may get a direct evidence concerning the valence quark
orbital angular momentum in the proton. This possible rotating effect is
estimated by using a proton-ensemble model.Comment: 9 pages and 2 figure
A Theorem on Frequency Function for Multiple-Valued Dirichlet Minimizing Functions
This paper discusses the frequency function of multiple-valued Dirichlet
minimizing functions in the special case when the domain and range are both two
dimensional. It shows that the frequency function must be of value k/2 for some
nonnegative integer k. Futhermore, by looking at the blowing-up functions, we
characterize the local behavior of the original Dirichlet minimizing function.Comment: 21 page
An Energy Reducing Flow for Multiple-Valued Functions
By the method of discrete Morse flows, we construct an energy reducing
multiple-valued function flow. The flow we get is Holder continuous with
respect to the L-2 norm. We also give another way of constructing flows in some
special cases, where the flow we get behaves like ordinary heat flow.Comment: 29 page
A regularity theory for multiple-valued Dirichlet minimizing maps
This paper discusses the regularity of multiple-valued Dirichlet minimizing
maps into the sphere. It shows that even at branched point, as long as the
normalized energy is small enough, we have the energy decay estimate. Combined
with the previous work by Chun-Chi Lin, we get our first estimate that m-2
dimensional Hausdorff measure of singular set is zero. Furthermore, by looking
at the tangent map and using dimension reduction argument, we show that the
singular set is at least of codimension 3.Comment: 27 page
Learning Gating ConvNet for Two-Stream based Methods in Action Recognition
For the two-stream style methods in action recognition, fusing the two
streams' predictions is always by the weighted averaging scheme. This fusion
method with fixed weights lacks of pertinence to different action videos and
always needs trial and error on the validation set. In order to enhance the
adaptability of two-stream ConvNets and improve its performance, an end-to-end
trainable gated fusion method, namely gating ConvNet, for the two-stream
ConvNets is proposed in this paper based on the MoE (Mixture of Experts)
theory. The gating ConvNet takes the combination of feature maps from the same
layer of the spatial and the temporal nets as input and adopts ReLU (Rectified
Linear Unit) as the gating output activation function. To reduce the
over-fitting of gating ConvNet caused by the redundancy of parameters, a new
multi-task learning method is designed, which jointly learns the gating fusion
weights for the two streams and learns the gating ConvNet for action
classification. With our gated fusion method and multi-task learning approach,
a high accuracy of 94.5% is achieved on the dataset UCF101.Comment: 8 pages, 4 figure
End-to-end Video-level Representation Learning for Action Recognition
From the frame/clip-level feature learning to the video-level representation
building, deep learning methods in action recognition have developed rapidly in
recent years. However, current methods suffer from the confusion caused by
partial observation training, or without end-to-end learning, or restricted to
single temporal scale modeling and so on. In this paper, we build upon
two-stream ConvNets and propose Deep networks with Temporal Pyramid Pooling
(DTPP), an end-to-end video-level representation learning approach, to address
these problems. Specifically, at first, RGB images and optical flow stacks are
sparsely sampled across the whole video. Then a temporal pyramid pooling layer
is used to aggregate the frame-level features which consist of spatial and
temporal cues. Lastly, the trained model has compact video-level representation
with multiple temporal scales, which is both global and sequence-aware.
Experimental results show that DTPP achieves the state-of-the-art performance
on two challenging video action datasets: UCF101 and HMDB51, either by ImageNet
pre-training or Kinetics pre-training.Comment: 10 pages, 6 figures, 6 tables. The explanation for the batch size is
added. Accepted by ICPR 201
Thermoelectric effect in a parallel double quantum dot structure
We discuss the thermoelectric properties assisted by the Fano effect of a
parallel double quantum dot (QD) structure. By adjusting the couplings between
the QDs and leads, we facilitate the nonresonant and resonant channels for the
Fano interference. It is found that at low temperature, Fano lineshapes appear
in the electronic and thermal conductance spectra, which can also be reversed
by an applied local magnetic flux with its phase factor . And, the
Fano effect contributes decisively to the enhancement of thermoelectric
efficiency. However, at the same temperature, the thermoelectric effect in the
case of is much more apparent, compared with the case of zero
magnetic flux. By the concept of Feynman path, we analyze the difference
between the quantum interferences in the cases of and . It
is seen that in the absence of magnetic flux the Fano interference originates
from the quantum interference among infinite-order Feynman paths, but it occurs
only between two lowest-order Feynman paths when . The increase of
temperature inevitably destroys the electron coherent transmission in each
paths. So, in the case of zero magnetic field, the thermoelectric effect
contributed by the Fano interference is easy to weaken by a little increase of
temperature.Comment: 8 pages, 4 figure
D Wave Heavy Mesons
We first extract the binding energy and decay constants of the
D wave heavy meson doublets and with QCD sum
rule in the leading order of heavy quark effective theory. Then we study their
pionic couplings using the light cone sum rule, from which the
parameter can also be extracted. We then calculate the pionic
decay widths of the strange/non-strange D wave heavy mesons and discuss
the possible candidates for the D wave charm-strange mesons. Further
experimental information, such as the ratio between and modes,
will be very useful to distinguish various assignments for .Comment: 10 pages, 3 figuers, 3 tables. Some descriptions changed, typos
corrected. Published version in PR
- β¦