17,689 research outputs found

    Enabling Quality-Driven Scalable Video Transmission over Multi-User NOMA System

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    Recently, non-orthogonal multiple access (NOMA) has been proposed to achieve higher spectral efficiency over conventional orthogonal multiple access. Although it has the potential to meet increasing demands of video services, it is still challenging to provide high performance video streaming. In this research, we investigate, for the first time, a multi-user NOMA system design for video transmission. Various NOMA systems have been proposed for data transmission in terms of throughput or reliability. However, the perceived quality, or the quality-of-experience of users, is more critical for video transmission. Based on this observation, we design a quality-driven scalable video transmission framework with cross-layer support for multi-user NOMA. To enable low complexity multi-user NOMA operations, a novel user grouping strategy is proposed. The key features in the proposed framework include the integration of the quality model for encoded video with the physical layer model for NOMA transmission, and the formulation of multi-user NOMA-based video transmission as a quality-driven power allocation problem. As the problem is non-concave, a global optimal algorithm based on the hidden monotonic property and a suboptimal algorithm with polynomial time complexity are developed. Simulation results show that the proposed multi-user NOMA system outperforms existing schemes in various video delivery scenarios.Comment: 9 pages, 6 figures. This paper has already been accepted by IEEE INFOCOM 201

    Neutron-skin thickness of finite nuclei in relativistic mean-field models with chiral limits

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    We study several structure properties of finite nuclei using relativistic mean-field Lagrangians constructed according to the Brown-Rho scaling due to the chiral symmetry restoration at high densities. The models are consistent with current experimental constraints for the equations of state of symmetric matter at both normal and supra-normal densities and of asymmetric matter at sub-saturation densities. It is shown that these models can successfully describe the binding energies and charge radii of finite nuclei. Compared to calculations with usual relativistic mean-field models, these models give a reduced thickness of neutron skin in ^{208}Pb between 0.17 fm and 0.21 fm. The reduction of the predicted neutron skin thickness is found to be due to not only the softening of the symmetry energy but also the scaling property of ρ\rho meson required by the partial restoration of chiral symmetry.Comment: Accepted version to appear in PRC (2007

    Large-mass neutron stars with hyperonization

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    Within a density-dependent relativistic mean-field model using in-medium meson-hadron coupling constants and meson masses, we explore effects of in-medium hyperon interactions on properties of neutron stars. It is found that the hyperonic constituents in large-mass neutron stars can not be simply ruled out, while the recently measured mass of the millisecond pulsar J1614-2230 can constrain significantly the in-medium hyperon interactions. Moreover, effects of nuclear symmetry energy on hyperonization in neutron stars are also discussed

    Manufacture’s Production and Pricing Strategies With Carbon Tax Policy and Strategic Customer Behavior

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    This paper investigates the manufacture’s production and pricing strategies with carbon tax policy and strategic customer behavior, and analyze the impact of carbon tax policy and its parameter on the manufacturer’s optimal strategies and maximum expected profit. We derive the optimal production, pricing strategies and maximum expected profit under the rational expectations equilibrium. The results show that the manufacturer’s optimal production quantity and maximum expected profit are decreasing in carbon tax rate, and the manufacturer’s optimal price is increasing in the carbon tax rate. Compared with the no carbon emission policy scenario, we prove that the manufacturer’s optimal production quantity decreases, the manufacturer’s optimal price increases, the manufacturer’s maximum expected profit decreases, and the carbon tax policy effectively reduces the manufacturer’s carbon emissions

    Consistency check of charged hadron multiplicities and fragmentation functions in SIDIS

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    We derived the conditions on certain combinations of integrals of the fragmentation functions of pion using HERMES data of the sum for the charged pion multiplicities from semi-inclusive deep-inelastic scattering (SIDIS) off the deuteron target. In our derivation the nucleon parton distribution functions (PDFs) are assumed to be isospin SU(2) symmetric. Similar conditions have also been obtained for the fragmentation functions (FFs) of kaon by the sum of charged kaon multiplicities as well. We have chosen several FFs to study the impact of those conditions we have derived. Among those FFs, only that produced in the nonlocal chiral-quark model (NLχ\chiQM) constantly satisfy the conditions. Furthermore, the ratios of the strange PDFs S(x)S(x) and the nonstrange PDFs Q(x,Q2)Q(x,Q^2) extracted from the charged pion and kaon multiplicities differ from each other significantly. Finally, we demonstrate that the HERMES pion multiplicity data is unlikely to be compatible with the two widely-used PDFs, namely CTEQ6M and NNPDF3.0.Comment: 11 pages, 5 fig

    Combined explanations of BB-physics anomalies, (g2)e,μ(g-2)_{e, \mu} and neutrino masses by scalar leptoquarks

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    We extend the contents of the standard model (SM) by introducing TeV-scale scalar leptoquarks to generate neutrino masses and explain some current observed deviations from the SM predictions, including the anomalous magnetic moments of charged leptons (electron and muon) and BB-physics anomalies (RK()R_{K^{(*)}} and RD()R_{D^{(*)}}). The model consists of SU(2)L\text{SU}(2)_L singlet leptoquark S1(3ˉ,1,1/3)S_1\sim (\bar{3}, 1, 1/3), doublet leptoquark R~2(3,2,1/6)\tilde{R}_2\sim (3, 2, 1/6) and triplet leptoquark S3(3ˉ,3,1/3)S_3\sim (\bar{3}, 3, 1/3). We combine the constraints arising from the low-energy lepton flavor violation, meson decay and mixing observables. We perform a detailed phenomenological analysis and identify the minimized texture of leptoquark Yukawa matrices to accommodate a unified explanation of the anomalies and neutrino oscillation data.Comment: 30 pages, 5 figures, matches published versio
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