High quality mesh plays an important role for finite element methods in science computation and numerical simulation.Whether the mesh quality is good or not,to some extent,it determines the calculation results of the ...High quality mesh plays an important role for finite element methods in science computation and numerical simulation.Whether the mesh quality is good or not,to some extent,it determines the calculation results of the accuracy and efficiency.Different from classic Lloyd iteration algorithm which is convergent slowly,a novel accelerated scheme was presented,which consists of two core parts:mesh points replacement and local edges Delaunay swapping.By using it,almost all the equilateral triangular meshes can be generated based on centroidal Voronoi tessellation(CVT).Numerical tests show that it is significantly effective with time consuming decreasing by 40%.Compared with other two types of regular mesh generation methods,CVT mesh demonstrates that higher geometric average quality increases over 0.99.展开更多
波达方向(direction of arrival,DOA)估计是阵列信号处理中的一个关键领域,而波达角(angle of arrival,AOA)则是其核心参数。将AOA估计作为主要研究目标,提高其在任意结构阵列中的准确性。通过分析现有文献中关于任意结构阵列的系统模型...波达方向(direction of arrival,DOA)估计是阵列信号处理中的一个关键领域,而波达角(angle of arrival,AOA)则是其核心参数。将AOA估计作为主要研究目标,提高其在任意结构阵列中的准确性。通过分析现有文献中关于任意结构阵列的系统模型,基于E-子空间理论,结合最大似然原理与Lloyd-like迭代算法,提出了一种新的子空间逼近迭代算法。此外,为了降低计算复杂度,结合MUSIC算法,提出了基于MUSIC峰值范围的迭代改进算法。最后,通过仿真验证了以上方法在毫米波信道估计中的有效性,相较于传统的MUSIC算法性能显著提升。展开更多
基金Project(11002121) supported by the National Natural Science Foundation of ChinaProject(09QDZ09) supported by Doctor Foundation of Xiangtan University, China+2 种基金Project(2009LCSSE11) supported by Hunan Key Laboratory for CSSE, ChinaProject(2011FJ3231) supported by Planned Science and Technology Project of Hunan Province,ChinaProject(12JJ3054) supported by the Provincial Natural Science Foundation of Hunan,China
文摘High quality mesh plays an important role for finite element methods in science computation and numerical simulation.Whether the mesh quality is good or not,to some extent,it determines the calculation results of the accuracy and efficiency.Different from classic Lloyd iteration algorithm which is convergent slowly,a novel accelerated scheme was presented,which consists of two core parts:mesh points replacement and local edges Delaunay swapping.By using it,almost all the equilateral triangular meshes can be generated based on centroidal Voronoi tessellation(CVT).Numerical tests show that it is significantly effective with time consuming decreasing by 40%.Compared with other two types of regular mesh generation methods,CVT mesh demonstrates that higher geometric average quality increases over 0.99.
文摘波达方向(direction of arrival,DOA)估计是阵列信号处理中的一个关键领域,而波达角(angle of arrival,AOA)则是其核心参数。将AOA估计作为主要研究目标,提高其在任意结构阵列中的准确性。通过分析现有文献中关于任意结构阵列的系统模型,基于E-子空间理论,结合最大似然原理与Lloyd-like迭代算法,提出了一种新的子空间逼近迭代算法。此外,为了降低计算复杂度,结合MUSIC算法,提出了基于MUSIC峰值范围的迭代改进算法。最后,通过仿真验证了以上方法在毫米波信道估计中的有效性,相较于传统的MUSIC算法性能显著提升。
文摘提出一种基于符号高阶统计量(HOS,high-order statistics)的MPSK调制信道衰落系数盲估计算法。针对平坦慢衰落信道模型,首先分析了MPSK调制符号高阶统计量特征,证明了MPSK调制符号的M次方符号的值是唯一的,而当1≤M′<M时,调制符号的M′次方符号在复平面上是对称分布的;之后利用此特征推导出MPSK调制阶数、初始相位和衰落系数估计算法。仿真实验表明,信噪比高于12 d B条件下,HOS算法估计性能与目前平坦慢衰落信道盲估计的主流方法 Lloyd-Max算法相同,而算法复杂度为Lloyd-Max算法的1/50,并且在接收样本符号较少的条件下HOS算法的均方误差曲线收敛于最小二乘估计理论下界。
