Pulse-order recursive method for inverse covariance matrix computation applied to space-time adaptive processing

The conventional space-time adaptive processing(STAP) method such as the typical sample matrix inversion(SMI)-based STAP method is difficult to implement for a practical system because intense computational complexity arises in calculating the inversion of a space-time covariance matrix directly.According to the block Hermitian matrix property of space-time covariance matrix,a new pulse-order recursive method is proposed in this paper to calculate the inverse covariance matrix for the STAP adaptive weight,which can reduce the computational complexity significantly.The proposed method requires initially calculating the inverse covariance matrix of the first pulse-order recursively based on the block Hermitian matrix property.In the following,the inversion of space-time covariance matrix is obtained recursively based on the previous pulse-order inverse covariance matrix.Next,the STAP adaptive weight is calculated based on the inversion space-time covariance matrix previously obtained.Compared with the conventional SMI-based STAP algorithms,the computational complexity of the proposed method is reduced to more than 50% for the same clutter suppression performance.This method can be applied to practical systems benefiting from small computational complexity and stable clutter suppression performance.     

二叉树的先序遍历和中序遍历的非递归算法

从二叉树先序遍历递归算法的执行过程的分析入手,总结出二叉树先序遍历的实质,从而得出利用栈的二叉树的非递归算法。最后,再从分析二叉树中序遍历与先序遍历过程实质的不同之处,得出了二叉树中序遍历的非递归算法。重点在于对二叉树先序和中序遍历过程实质的分析。     

递归程序非递归化算法在企业生产中的应用

由递归算法直接转换成相应的非递归算法能有效地提高程序的执行效率。本文针对一个企业材料截断应用案例．通过数学建模、算法分析与实现,证明效果很好。     

基于梯度投影的图像盲复原算法

为了利用多帧退化图像信息快速恢复出高质量的图像,提出了一种新的递归梯度投影多帧图像盲复原算法。该算法充分利用多帧图像的先验信息,首先给出一种能够有效抑制噪声放大的新的代价函数,然后通过梯度投影算法对新的代价函数进行最小化以推导出迭代公式,最后通过频率域多次递归迭代运算对退化图像进行复原。模拟实验结果证明该算法运算快速,对于不同高斯噪声级别和不同PSF衰退的图像,均能够清晰地恢复出图像细节特征、同时也能够准确地恢复出衰退PSF。     

游戏程序设计中若干问题的探讨

游戏编程是当今程序设计的一个热点,开发过程会遇到各种各样的问题。通过限制构造函数和拷贝函数,设计一个单体全局管理类,可以避免不合适的调用。采用分块技术加栽地图,可以在时空性能上优化游戏。阐述了D3D的空间坐标变换。分析了万向节死锁问题发生的原因,并提出了解决办法。     

安徽省地震会商系统软件界面设计研究

基于ARCGis9.2的安徽省地震会商系统不仅需要强大的技术功能,还需要友好和一目了然的界面,这样不仅让会商报告者思路清晰,也能使会商观众更加清晰了解地震预报会商内容,从而为决策者更好应对不同地点和不同大小的地震发生可能性做出科学的决策;引入flash8作为软件系统的界面,用flash调用各个模块,无论从界面和功能上都较好的解决了这一问题。     

基于T-S模型的自适应模糊广义预测控制

对一类非线性系统,利用一种基于模糊规则的快速模糊辨识方法建立起系统的T—S模型,并基于该模型应用局部递推最小二乘方法根据采样值对模型参数进行在线修正,根据系统动态线性化模型采取广义预测控制策略,从而实现了基于T—S模糊模型的非线性系统自适应模糊预潮控制。与以往的模糊广义预测控制算法相比,此方法简单,而且较大地减少计算量,适合于在线控制。通过仿真研究验证所提方法的有效性。     

一种新的基于遗忘因子的递推子空间辨识算法

针对工业系统中广泛存在的时变特性, 提出一种新的递推子空间辨识算法, 实现对系统状态空间模型的在线递推估计. 为更好地跟踪系统时变特性, 研究基于遗忘因子的输入输出数据矩阵构造机制, 以提高递推算法的收敛速度; 针对算法中奇异值分解的求解问题, 将梯度型算法引入基于遗忘因子的状态子空间跟踪中, 实现对广义能观测矩阵的估计, 避免了子空间近似带来的估计有偏性; 该算法计算简单有效, 且对初值具有更高的鲁棒性; 最后给出该递推算法的性能分析, 理论证明其收敛性, 并通过仿真实例验证算法的有效性.     

Complex radial basis function networks trained by QR‐decomposition recursive least square algorithms applied in behavioral modeling of nonlinear power amplifiers

In this article, we propose a novel complex radial basis function network approach for dynamic behavioral modeling of nonlinear power amplifier with memory in 3 G systems. The proposed approach utilizes the complex QR‐decomposition based recursive least squares (QRD‐RLS) algorithm, which is implemented using the complex Givens rotations, to update the weighting matrix of the complex radial basis function (RBF) network. Comparisons with standard least squares algorithms, in batch and recursive process, the QRD‐RLS algorithm has the characteristics of good numerical robustness and regular structure, and can significantly improve the complex RBF network modeling accuracy. In this approach, only the signal's complex envelope is used for the model training and validation. The model has been validated using ADS simulated and real measured data. Finally, parallel implementation of the resulting method is briefly discussed. © 2009 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009.     

卷草纹的艺术语言及其现代延展设计

卷草纹是中国传统装饰纹样之一,它的形成和发展记载了中国装饰艺术旺盛的生命力。本文分析了卷草纹的发展过程、形象构成以及艺术特征,并通过具体案例诠释了它在现代设计各个领域的延展和应用。旨在探索传统装饰纹样在现代设计中的传承与发展的方向。