9,428 research outputs found
Chinese User Service Intention Classification Based on Hybrid Neural Network
In order to satisfy the consumers' increasing personalized service demand,
the Intelligent service has arisen. User service intention recognition is an
important challenge for intelligent service system to provide precise service.
It is difficult for the intelligent system to understand the semantics of user
demand which leads to poor recognition effect, because of the noise in user
requirement descriptions. Therefore, a hybrid neural network classification
model based on BiLSTM and CNN is proposed to recognize users service
intentions. The model can fuse the temporal semantics and spatial semantics of
the user descriptions. The experimental results show that our model achieves a
better effect compared with other models, reaching 0.94 on the F1 score.Comment: CMVIT201
Formation of Millisecond Pulsars with Low-Mass Helium White Dwarf Companions in Very Compact Binaries
Binary millisecond pulsars (BMSPs) are thought to have evolved from low-mass
X-ray binaries (LMXBs). If the mass transfer in LMXBs is driven by nuclear
evolution of the donor star, the final orbital period is predicted to be well
correlated with the mass of the white dwarf (WD), which is the degenerate He
core of the donor. Here we show that this relation can be extended to very
small WD mass () and narrow orbital period (about a
few hours), mainly depending on the metallicities of the donor stars. There is
also discontinuity in the relation, which is due to the temporary contraction
of the donor when the H-burning shell crosses the hydrogen discontinuity. BMSPs
with low-mass He WD companions in very compact binaries can be accounted for if
the progenitor binary experienced very late Case A mass transfer. The WD
companion of PSR J1738+0333 is likely to evolve from a Pop~II star. For PSR
J0348+0432, to explain its extreme compact orbit in the Roche lobe-decoupling
phase, even lower metallicity () is required.Comment: 18 pages, 6 figures, accepted for publication in Ap
Evolution of Transient Low-Mass X-ray Binaries to Redback Millisecond Pulsars
Redback millisecond pulsars (hereafter redbacks) are a sub-population of
eclipsing millisecond pulsars in close binaries. The formation processes of
these systems are not clear. The three pulsars showing transitions between
rotation- and accretion-powered states belong to both redbacks and transient
low-mass X-ray binaries (LMXBs), suggesting a possible evolutionary link
between the them. Through binary evolution calculations, we show that the
accretion disks in almost all LMXBs are subject to the thermal-viscous
instability during certain evolutionary stages, and the parameter space for the
disk instability covers the distribution of known redbacks in the orbital
period - companion mass plane. We accordingly suggest that the abrupt reduction
of the mass accretion rate during quiescence of transient LMXBs provides a
plausible way to switch on the pulsar activity, leading to the formation of
redbacks, if the neutron star has been spun up to be an energetic millisecond
pulsar. We investigate the evolution of redbacks, taking into account the
evaporation feedback, and discuss its possible influence on the formation of
black widow millisecond pulsars.Comment: 27 pages, 5 figures, accepted by Ap
An Intrinsic Advantage of Sexual Reproduction
The prevalence of sexual reproduction ("sex") in eukaryotes is an enigma of
evolutionary biology. Sex increases genetic variation only tells its long-term
superiority in essence. The accumulation of harmful mutations causes an
immediate and ubiquitous pressure for organisms. Contrary to the common sense,
our theoretical model suggests that reproductive rate can influence
initiatively the accumulation of harmful mutations. The interaction of
reproductive rate and the integrated harm of mutations causes a critical
reproductive rate R*. A population will become irreversibly extinct once the
reproductive rate reduces to lower than R*. A sexual population has a R* lower
than 1 and an asexual population has a R* higher than 1. The mean reproductive
rate of a population reached to the carrying capacity has to reduce to 1. That
explains the widespread sex as well as the persistence of facultative and
asexual organisms. Computer simulations support significantly our conclusion.Comment: 32 pages, 6 figure
Restrictions on purely kinetic k-essence
We restrict purely kinetic k-essence. Assuming the equation of state is a
power law of the kinetic energy: , to obtain accelerated
phases, we must have as one of necessary conditions, constrained
from the conditions for stability and causality, and the k-essence must behave
like phantom. We also study the evolutions of the equation of state and the
speed of sound with numerical simulation.Comment: 4 pages, 2 figure
Asymptotic incidence energy and Laplacian-energy-like invariant of the Union Jack lattice
The incidence energy of a graph , defined as the sum of
the singular values of the incidence matrix of a graph , is a much studied
quantity with well known applications in chemical physics. The
Laplacian-energy-like invariant of is defined as the sum of square roots of
the Laplacian eigenvalues. In this paper, we obtain the closed-form formulae
expressing the incidence energy and the Laplacian-energy-like invariant of the
Union Jack lattice. Moreover, the explicit asymptotic values of these
quantities are calculated by utilizing the applications of analysis approach
with the help of calculational software
On the Capacity of p2p Multipoint Video Conference
In this paper, The structure of video conference is formulated and the
peer-assisted distribution scheme is constructed to achieve optimal video
delivery rate in each sub-conference. The capacity of conference is proposed to
referee the video rate that can be supported in every possible scenario. We
have proved that, in case of one user watching only one video, 5/6 is a lower
bound of the capacity which is much larger than 1/2, the achievable rate of
chained approach in [2]. Almost all proofs in this paper are constructive. They
can be applied into real implementation directly with a few modifications
Secure quantum key distribution in an easy way
Secure quantum key distribution can be achieved with an imperfect
single-photon source through implementing the decoy-state method. However,
security of all those theoretical results of decoy-state method based on the
original framework raised by Hwang needs monitoring the source state very
carefully, because the elementary proposition that the counting rates of the
same state from different sources are equal does not hold in general when the
source is unstable. Source intensity monitoring greatly decreases the system
efficiency. Here without using Hwang's proposition for stable source, we
present a sufficient condition for a secure decoy-state protocol without
monitoring the source intensity. The passive 2-intensity protocol proposed by
Adachi, Yamamoto, Koashi, and Imoto(AYKI) (Phys. Rev. Lett. 99, 180503 (2007)
satisfies the condition. Therefore, the protocol can always work securely
without monitoring the source state or switching the source intensity. We also
show that our result can greatly improve the key rate of the 3-intensity
protocol with a fluctuating coherent-state source
Analysis of stability of community structure across multiple hierarchical levels
The analysis of stability of community structure is an important problem for
scientists from many fields. Here, we propose a new framework to reveal hidden
properties of community structure by quantitatively analyzing the dynamics of
Potts model. Specifically we model the Potts procedure of community structure
detection by a Markov process, which has a clear mathematical explanation.
Critical topological information regarding to multivariate spin configuration
could also be inferred from the spectral significance of the Markov process. We
test our framework on some example networks and find it doesn't have resolute
limitation problem at all. Results have shown the model we proposed is able to
uncover hierarchical structure in different scales effectively and efficiently.Comment: 7 pages, 3 figure
Surface Normals in the Wild
We study the problem of single-image depth estimation for images in the wild.
We collect human annotated surface normals and use them to train a neural
network that directly predicts pixel-wise depth. We propose two novel loss
functions for training with surface normal annotations. Experiments on NYU
Depth and our own dataset demonstrate that our approach can significantly
improve the quality of depth estimation in the wild
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