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宽带接入认证平台探讨 总被引:2,自引:0,他引:2
本就宽带业务发展对认证计费的要求,分析了接入认证的类型和方法,论述了建立统一接入平台、进行集中认证,即采用“分散接入、集中认证计费”的网络方案以及接入设备的技术要点。 相似文献
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Perturbation Analysis on Guided Waves in a Fluid-Filled Borehole Surrounded by a Cubic Crystal Anisotropic Medium
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The perturbation method is employed to analyse the guided waves in a borehole surrounded by a cubic crystal medium for the first time. The cubic crystal medium is regarded as a reference unperturbed isotropic state added to the perturbation. The dispersion characteristics of Stoneley wave, pseudo-Rayleigh wave, flexural wave, and screw wave are investigated in detail. It is found that dispersion of the guided waves excited by monopole and dipole sources does not depend on the azimuth of the source, whereas the dispersion of screw wave excited by quadrupole source is significantly related to the azimuth of the source. Screw waves propagated along different azimuth in the borehole can be split. This is different from screw waves in transversely isotropic media (hexagonal crystal), which have been widely studied. 相似文献
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目前我军装备备件保障通常采用三级保障模式,以各级备件期望短缺数量之和最小为目标,研究在不同库存水平条件下,三级备件保障系统的备件库存优化模型.经示例分析,验证了该模型的可行性和有效性,该结果可为多级备件保障提供理论依据. 相似文献
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本文介绍的是平面阵列天线面精度测量值的分析计算方法。由于天线面精度对天线副瓣,特别是低副瓣天线的副瓣影响甚大。近年来越发为设计人员所重视,在完成天线安装后得到可靠的阵面面精度测量数据以便于设计人员进行评估和分析,用本文提出的数据处理方法进行测量值分析计算不失为一种简单易行的办法。 相似文献
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根据由格林函数方法导得的满壳层相邻核能谱所满足的方程,在取质量算符(按G矩阵展开)的一级近似下,应用Hamada-Johnston势,计算了A=15核的0s1/2、0p3/2、0p(1/2)空穴态和A=17核的0d5/2、1s1/2、0d3/2粒子态能谱与相应的跃迁振幅比,计算中严格顾及了G矩阵的能量相关性。文中对能谱方程自洽求解的收敛速度以及截断近似和选作表象的单粒谐振子势参数对计算结果的影响进行了考察。本文还讨论了质心伪态的消除问题,给出了引入质心谐振子势后计算G矩阵的具体公式。除Os(1/2)态外,本文算得的能谱均消除了质心伪态的影响。与以往重整化的Brueckner-Hartree-Fock(RBHF)计算相比,本文采用的方法计算简单,结果与实验符合颇好。 相似文献
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Asymptotic Analysis of Vertical Branch-Cut Integral of Shear Waves in a Fluid-Filled Borehole Utilizing the Steepest-Descent Method
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We obtain an asymptotic solution to the vertical branch-cut integral of shear waves excited by an impulsive pressure point source in a fluid-filled borehole, by taking the effect of the infinite singularity of the Hankel functions related to shear waves in the integrand at the shear branch point into account and using the method of steepest-descent to expand the vertical branch-cut integral of shear waves. It is theoretically proven that the saddle point of the integrand is located at ks-i/z, where ks and z are the shear branch point and the offset. The continuous and smooth amplitude spectra and the resonant peaks of shear waves are numerically calculated from the asymptotic solution. These asymptotic results are generally in agreement with the numerical integral results. It is also found by the comparison and analysis of two results that the resonant factor and the effect of the normal and leaking mode poles around the shear branch point lead to the two-peak characteristics of the amplitude spectra of shear waves in the resonant peak zones from the numerical integral calculations. 相似文献