9,428 research outputs found

    Chinese User Service Intention Classification Based on Hybrid Neural Network

    Full text link
    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

    Full text link
    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 (∼0.14−0.17 M⊙\sim 0.14-0.17\,M_\odot) 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 (Z=0.0001Z=0.0001) is required.Comment: 18 pages, 6 figures, accepted for publication in Ap

    Evolution of Transient Low-Mass X-ray Binaries to Redback Millisecond Pulsars

    Full text link
    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

    Full text link
    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

    Full text link
    We restrict purely kinetic k-essence. Assuming the equation of state is a power law of the kinetic energy: w=w0Xαw=w_0X^{\alpha}, to obtain accelerated phases, we must have α>0\alpha>0 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

    Full text link
    The incidence energy IE(G)\mathscr{IE}(G) of a graph GG, defined as the sum of the singular values of the incidence matrix of a graph GG, is a much studied quantity with well known applications in chemical physics. The Laplacian-energy-like invariant of GG 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

    Full text link
    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

    Full text link
    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

    Full text link
    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

    Full text link
    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
    • …
    corecore