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不可压缩流稳定性的多尺度分析与数值模拟
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作者 张玲 欧阳洁 《计算机工程与应用》 CSCD 北大核心 2010年第3期23-26,共4页
为了研究小尺度不可压缩周期流的稳定性,应用多尺度分析方法获得控制其扰动流的大尺度均场方程。对稳态平行流,根据均场方程得到控制大尺度扰动流稳定性的涡流粘性系数。为了验证多尺度理论预测的正确性,采用可以避免速度场和压力场失... 为了研究小尺度不可压缩周期流的稳定性,应用多尺度分析方法获得控制其扰动流的大尺度均场方程。对稳态平行流,根据均场方程得到控制大尺度扰动流稳定性的涡流粘性系数。为了验证多尺度理论预测的正确性,采用可以避免速度场和压力场失耦且具有高精度的时间分裂拟谱算法,对不同参数和初始条件下的均场方程以及原始扰动流控制方程进行了数值求解。 展开更多
关键词 稳定性 多尺度分析 均场方程 拟谱算法
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Physical-Layer Encryption in Massive MIMO Systems with Spatial Modulation 被引量:1
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作者 Sixin Wang Wei Li Jing Lei 《China Communications》 SCIE CSCD 2018年第10期159-171,共13页
Massive multiple input and multiple output(MIMO) is a key technology of the fifth generation(5 G) wireless communication systems, which brings various advantages, such as high spectral efficiency and energy efficiency... Massive multiple input and multiple output(MIMO) is a key technology of the fifth generation(5 G) wireless communication systems, which brings various advantages, such as high spectral efficiency and energy efficiency. In MIMO system, spatial modulation(SM) has recently emerged as a new transmission method. In this paper, in order to improve the security in SM-MIMO, a physical layer encryption approach named chaotic antenna-index three-dimensional modulation and constellation points rotated(CATMCPR) encryption scheme is proposed, which utilizes the chaotic theory and spatial modulation techniques. The conventional physical-layer encryption in SM-MIMO suffers from spectral efficiency(SE) performance degradation and usually needs a preshared key, prior channel state information(CSI) or excess jamming power. By contrast, we show that the CATMCPR scheme can not only achieve securely communication but also improve above drawbacks. We evaluate the performances of the proposed scheme by an analysis and computer simulations. 展开更多
关键词 massive MIMO chaotic system physical layer security antenna-index spatial modulation
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带乘性噪声的空间分数阶随机非线性Schr?dinger方程的广义多辛算法
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作者 刘子源 梁家瑞 +1 位作者 钱旭 宋松和 《计算数学》 CSCD 北大核心 2019年第4期440-452,共13页
带乘性噪声的空间分数阶随机非线性Schrodinger方程是一类重要的方程,可应用于描述开放非局部量子系统的演化过程·该方程为一个无穷维分数阶随机Hamilton系统,且具有广义多辛结构和质量守恒的性质.针对该方程的广义多辛形式,在空... 带乘性噪声的空间分数阶随机非线性Schrodinger方程是一类重要的方程,可应用于描述开放非局部量子系统的演化过程·该方程为一个无穷维分数阶随机Hamilton系统,且具有广义多辛结构和质量守恒的性质.针对该方程的广义多辛形式,在空间上采用拟谱方法离散分数阶微分算子,在时间上则采用隐式中点格式,构造出一类保持全局质量的广义多辛格式.对行波解和平面波解等进行数值模拟,结果验证了所构造格式的有效性和保结构性质,时间均方收敛阶约在0.5到1之间. 展开更多
关键词 分数阶随机非线性Schrodinger方程 乘性噪声广义多辛算法 质量守恒律 拟谱算法
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New computational treatment of optical wave propagation in lossy waveguides
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作者 Jian-xin ZHU Guan-jie WANG 《Frontiers of Information Technology & Electronic Engineering》 SCIE EI CSCD 2015年第8期646-653,共8页
In this paper, the optical wave propagation in lossy waveguides is described by the Helmholtz equation with the complex refractive-index, and the Chebyshev pseudospectral method is used to discretize the transverse op... In this paper, the optical wave propagation in lossy waveguides is described by the Helmholtz equation with the complex refractive-index, and the Chebyshev pseudospectral method is used to discretize the transverse operator of the equation. Meanwhile, an operator marching method, a one-way re-formulation based on the Dirichlet- to-Neumann (DtN) map, is improved to solve the equation. NumericM examples show that our treatment is more efficient. 展开更多
关键词 Adjoint operator ORTHOGONAL CHEBYSHEV Pseudospectral method Dirichlet-to-Neumann map
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