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孔径、缝隙散射在工业、军事领域,尤其是雷达目标特性分析和目标识别方面有重要的应用价值.文章将孔隙散射依次分为单孔隙二维散射、单孔隙三维散射、多孔隙散射等三类,从混合算法、并行计算等方面介绍了孔隙散射问题研究的发展状况.结合孔隙散射在弹丸姿态测量中的运用,建议应当加强对散射问题物理意义理解和研究. 相似文献
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LFCM算法作为一种划分式聚类算法,它根据新旧聚类中心之差是否小于设定阈值决定是否停止迭代,但存在聚类准确率偏低的缺陷.熵是信息论中有效度量不确定性的一项指标.为此,文章提出了一种基于迭代信息熵权的改进LFCM算法,该算法将熵权法与LFCM算法进行了有效的融合.算法的改进思路为:(1)输入样本结合隶属度函数,求得数据矩阵,根据该数据矩阵求取新的信息熵和权重;(2)目标函数采用权重函数,算法通过判断新旧权重的差值是否小于设定阈值作为停止迭代条件.仿真实验结果表明,基于迭代信息熵权的改进LFCM算法可以有效提高聚类准确率及紧凑率. 相似文献
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The superposition of basic non-diffracting beams triggered new research hotspots lately, laying opportunities for long-distance wireless optical communication. The Lommel-Gaussian (LMG) beam formed by the superposition of Bessel-Gaussian light not only possesses non-diffraction feature, but also has tunable symmetry. With the help of Poynting vector analysis, we observed a smaller radial energy flow component during the propagation of the high order symmetrical LMG beam, which allows it to maintain the original beam profile over long distance. Thanks to the energy oscillation of the mainlobe and sidelobes, the mainlobe blocked by the symmetrical LMG beam can be restored. Also, the random phase screen with angular spectrum method is used to describe the beam behaviors in turbulence. The results show that the symmetry LMG is preferred in free space optical communication, and the asymmetric LMG performs poorly due to asymmetric energy transfer. 相似文献
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