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弱目标检测与定位的空时谱积分方法
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作者 李冰 蒋飚 王麟煜 《声学技术》 CSCD 2012年第3期314-317,共4页
研究了一种基于空时谱积分最大化的弱目标检测与距离估计技术。对常规波束形成输出在各频率和方位处的信号功率进行长时间的非相干积累,根据长时间空时谱积分的极大值来确定目标的空间位置,并且对频率-方位谱采用三次样条内插以提高定... 研究了一种基于空时谱积分最大化的弱目标检测与距离估计技术。对常规波束形成输出在各频率和方位处的信号功率进行长时间的非相干积累,根据长时间空时谱积分的极大值来确定目标的空间位置,并且对频率-方位谱采用三次样条内插以提高定位精度。由于增大了积分时间,大大提高了对弱目标的检测能力,并且不需要细致的环境参数,提高了测距定位的稳健性。数值分析验证了在低信噪比下,检测和定位性能的提高,并给出了测距误差分析。 展开更多
关键词 弱目标检测 被动测距 积分
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基于遗传算法的空时综合定位方法及其在数字信号处理器上的实现 被引量:5
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作者 柯碧辉 毛卫宁 《声学学报》 EI CSCD 北大核心 2003年第2期167-170,共4页
提出了一种基于遗传算法的空时积分(STI)定位方法,它能克服传统STI定位方法的运算量大或初值选取难的问题。通过采取降采样、并行计算和自适应处理等方法,解决遗传算法本身存在的不成熟收敛和实时性差的缺陷,使STI定位方法能有效地、精... 提出了一种基于遗传算法的空时积分(STI)定位方法,它能克服传统STI定位方法的运算量大或初值选取难的问题。通过采取降采样、并行计算和自适应处理等方法,解决遗传算法本身存在的不成熟收敛和实时性差的缺陷,使STI定位方法能有效地、精确地进行水下目标定位。该定位方法是在DSP上实现,充分考虑了DSP自身的特点。正是遗传算法和DSP系统的有效结合使得该STI定位方法具有一定的实用性。 展开更多
关键词 遗传算法 综合定位方法 数字信号处理器 声呐 空时积分 目标运动分析 水下目标定位
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Functional Integrals and Quantum Fluctuations on Two-Dimensional Noncommutative Space-Time 被引量:5
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作者 YAN Jun 《Communications in Theoretical Physics》 SCIE CAS CSCD 2009年第9期445-448,共4页
The generalized Thirring model with impurity coupling is defined on two-dimensional noncommutativespace-time,a modified propagator and free energy are derived by means of functional integrals method.Moreover,quantum f... The generalized Thirring model with impurity coupling is defined on two-dimensional noncommutativespace-time,a modified propagator and free energy are derived by means of functional integrals method.Moreover,quantum fluctuations and excitation energies are calculated on two-dimensional black hole and soliton background. 展开更多
关键词 functional integrals quantum fluctuations noncommutative space-time
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Painlevé Integrability of Nonlinear Schrdinger Equations with both Space-and Time-Dependent Coefficients
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作者 Kyoung Ho Han H.J.Shin 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第12期1101-1108,共8页
We investigate the Painleve integrabiiity of nonautonomous nonlinear Schr6dinger (NLS) equations with both space-and time-dependent dispersion, nonlinearity, and external potentials. The Painleve analysis is carried... We investigate the Painleve integrabiiity of nonautonomous nonlinear Schr6dinger (NLS) equations with both space-and time-dependent dispersion, nonlinearity, and external potentials. The Painleve analysis is carried out without using the Kruskal's simplification, which results in more generalized form of inhomogeneous equations. The obtained equations are shown to be reducible to the standard NLS equation by using a point transformation. We also construct the corresponding Lax pair and carry out its Kundu-type reduction to the standard Lax pair. Special cases of equations from choosing limited form of coefficients coincide with the equations from the previous Painleve analyses and/or become unknown new equations. 展开更多
关键词 Painleve integrability inhomogeneous nonlinear Schroedinger equation point transformation
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Positive energy theorem for(4+1)-dimensional asymptotically anti-de Sitter spacetimes
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作者 WANG YaoHua XU Xu 《Science China Mathematics》 SCIE 2014年第2期389-396,共8页
We define the total energy-momenta for(4+1)-dimensional asymptotically anti-de Sitter spacetimes,which comes from the boundary terms at infinity in the integral form of the Weitzenbck formula.Then we prove the positiv... We define the total energy-momenta for(4+1)-dimensional asymptotically anti-de Sitter spacetimes,which comes from the boundary terms at infinity in the integral form of the Weitzenbck formula.Then we prove the positive energy theorem for such spacetimes,following Witten’s original argumentsfor the positive energy theorem in asymptotically flat spacetimes. 展开更多
关键词 positive energy theorem asymptotically anti-de Sitter spacetimes
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