盖氏圆准则信源数估计算法的分析与改进

为了减少盖氏圆准则信源数估计算法的运算量并且提高信源数估计的精度,根据噪声空间与阵列导向矩阵的正交性原理,设计了基于特征空间的信源数估计算法(Estimator Based on Eigenvectors,EBE).EBE构造时空相关矩阵,利用色噪声在时间上相关性比较弱的特点,实现对空间色噪声的抑制.在空间白噪声环境下和空间色噪声环境下测试了EBE信源数估计的性能并且与传统的盖氏圆准则和其它色噪声类信源数估计的一些算法比较,证明了EBE在空间白噪声和空间色噪声环境下的有效性.EBE不仅节省了盖氏圆准则信源数估计中一次特征分解的运算量,并且同时提高了信源数估计的性能.     

基于子空间和LMS的线性共轭半盲多用户检测

针对实际的多载波码分多址上行链路,在基于最小均方实现的最小输出能量盲多用户检测(LMS-MOE)的基础上,提出MC-CDMA系统下一种基于子空间跟踪和LMS的线性共轭半盲多用户检测算法。该算法充分利用小区内所有用户的扩频码和伪自相关矩阵的信息使系统的性能得到了提高,采用修正的紧缩近似投影子空间跟踪信号子空间,从而避免特征值分解使计算复杂度显著降低。仿真实验验证了该算法的有效性和可行性。     

基于子空间方法的自适应半盲多用户检测

提出MC-CDMA系统下一种基于子空间方法的自适应半盲多用户检测算法。该算法通过利用小区内所有用户的扩频码设计了一种基于MOE准则的半盲检测器。针对Chebyshev逼近算法受到来自噪声子空间分量的影响导致性能下降的问题,提出一种子空间约束Chebyshev逼近算法,并使用该算法自适应得到权向量。为了减少计算复杂度,采用修正的PASTd算法自适应跟踪信号子空间。仿真实验验证了该算法的有效性和可行性。     

基于子空间法的空时分组码系统信道盲估计

结合多信道子空间理论,结合空时分组码的正交特性,提出了新的盲信道估计算法。首先,根据空时分组码结构特点,将原编码矩阵分解,并将接收矩阵合理地构造,把原信道矩阵重新构造成新的重构信道矩阵。然后求出重构信道矩阵的噪声子空间,之后利用信号子空间与噪声子空间正交特性,构造出信道矩阵作为变量的线性方程组,因而可以得到信道矩阵的闭式解。对三种典型的空时分组码进行仿真验证,仿真结果表明本算法的有效性。     

一种改进的外积分解(OPDA)算法

传统的外积分解(OPDA outer-product decomposition algorithm)算法虽然允许信道阶数被过估计,但该情况下的均衡结果不够理想。针对这一问题,提出一种改进的算法,即对过估计出的信道响应修正后再进行均衡。改进的算法较之原算法能更好的抑制剩余码间干扰,且在阶数估计上有更好的鲁棒性。通过计算机仿真证明了该算法的有效性。     

过程系统仿真中的分离技术

首先阐述了过程系统建模与仿真发展的现状,并就目前过程系统建模与仿真的智能化,集成化的需要,阐述了过程系统建模与仿真中的管线与设备分离,算法与数据分离,环境与模型分离的设计思想,最后,给出了应用系统的体系结构。     

Underdetermined DOA estimation and blind separation of non-disjoint sources in time-frequency domain based on sparse representation method

This paper deals with the blind separation of nonstation-ary sources and direction-of-arrival （DOA） estimation in the under-determined case, when there are more sources than sensors. We assume the sources to be time-frequency （TF） disjoint to a certain extent. In particular, the number of sources presented at any TF neighborhood is strictly less than that of sensors. We can identify the real number of active sources and achieve separation in any TF neighborhood by the sparse representation method. Compared with the subspace-based algorithm under the same sparseness assumption, which suffers from the extra noise effect since it can-not estimate the true number of active sources, the proposed algorithm can estimate the number of active sources and their cor-responding TF values in any TF neighborhood simultaneously. An-other contribution of this paper is a new estimation procedure for the DOA of sources in the underdetermined case, which combines the TF sparseness of sources and the clustering technique. Sim-ulation results demonstrate the validity and high performance of the proposed algorithm in both blind source separation （BSS） and DOA estimation.     

Image separation using wavelet-complex shearlet dictionary

This paper presents a new method for image separation through employing a combined dictionary consisting of wavelets and complex shearlets. Because the combined dictionary sparsely represents points and curvilinear singularities respectively, the image can be decomposed into pointlike and curvelike parts as accurate as possible. The proposed method based on the geo- metric separation theory introduced by Donoho in 2005 shows that accurate geometric separation of the morphologically distinct fea- tures of points and curves can be achieved by l1 minimization. The experimental results show that the proposed method can not only be effective but also greatly reduce the computing time.     

Aspen Plus在化工专业课程教学中的应用

为了培养学生的工程实践能力,将Aspen Plus软件应用于化学工程与工艺专业课程教学.介绍了Aspen Plus软件在课堂教学中的应用,从而提高学生对化工专业课程的理解能力,增强学生的工程意识,有助于学生学习兴趣的提高.     

强和弱

<正>动物界的准则历来是弱肉强食,这似乎是颠扑不破的真理。然而,现实并非都如此。鲨鱼,被称为大海里的"杀戮机器",众多的海洋生物都葬身于鲨鱼腹中。然而,身形庞大的鲨鱼,它的天敌却是一条小小的盲鳗。盲鳗的口像个椭圆形的吸盘,里面镶着锐利的牙齿。它慢慢向一条鲨鱼靠近,并悄悄用吸盘似的嘴吸附在鲨鱼身上。起初,鲨