A feasibility study of a direct-mapping parallel processing method to solve linear equations in load-flow calculation

With the growing size and complexity of power systems, system analysis—such as transients calculation—takes much time. Hence, fast calculation methods are required. Although parallel processing is a hopeful method, there have been difficulties in the parallel solution of linear equations which appear in power-flow calculations by the Newton-Raphson method. This paper aims at the fast calculation of the power-flow problem by means of parallel processing. In order to improve the suitability to the parallel solution of the differential equation in transients calculation, we assume the use of a direct-mapping parallel processing machine to map directly the network of a power system onto a network of processors. Under this assumption, we propose a new parallel-processing-oriented method in which the linear equation is solved by linear iterations between nodes with Aitken acceleration. We simulate the method on three model power systems and compare this Parallel Iterative Method (PIN) with a Parallel Direct Method (PDM) which uses the banded matrix according to the number of operations required. As a result, we can expect that PIM may solve linear equations faster than PDM with m processors, although the PIM might be inferior to the PDM with m × m processors, where m denotes the half-band width of the banded matrix.     

系数矩阵含参数分裂形式的SOR迭代法收敛性分析

给出预条件方后线性方程组的系数矩阵的一类含参数的分裂形式,使系数矩阵的分裂更加一般化,同时讨论在该形式下的SOR迭代法的收敛性,并与一般的预条件方法进行比较分析,说明这种方法收敛性更好,最后找到参数的最优选取.     

多级和多程脉冲激光放大器的逆问题

采用脉冲分割模型和逐次逼近迭代法，对任意空间和时间分布波形的激光通过任意增益分布多级和多程激光放大系统传输的逆问题，即给定输出脉冲和多级／多程放大系统参数，求输入脉冲波形和能量密度，作了详细研究和计算模拟     

多平面真三维全息显示

提出了一种多平面迭代算法,通过计算多个平面之间光波的前向和后向传播得到全息面的相位分布的恢复,并且用各个平面上的目标图像的振幅来限定传播过程中的光强。该方法将三维的光场分布离散化为相干光在多个二维平行平面上的同时调制,大幅减少了全息计算量。利用纯相位空间光调制器加载计算全息图,在三个屏幕上依次得到三个不同景深的图像,对于人眼调焦过程进行了模拟,实现了多平面真三维显示。系统简单,对于运算处理与显示器件的要求不高,易于实现。     

Optimal-correlation-based reconstruction for distributed compressed video sensing

Distributed compressed video sensing (DCVS) is a framework that integrates both compressed sensing and distributed video coding characteristics to achieve a low-complexity video coding. However, how to design an efficient joint reconstruction by leveraging more realistic signal models is still an open challenge. In this paper, we present a novel optimal-correlation-based reconstruction method for compressively sampled videos from multiple measurement vectors. In our method, the sparsity is mainly exploited through inter-signal correlations rather than the traditional frequency transform, wherein the optimization is not only over the signal space to satisfy data consistency but also over all possible linear correlation models to achieve minimum-l₁-norm correlation noise. Additionally, a two-phase Bregman iterative based algorithm is outlined for solving the optimization problem. Simulation results show that our proposal can achieve an improved reconstruction performance in comparison to the conventional approaches, and especially, offer a 0.7–9.9 dB gain in the average PSNR for DCVS.     

CDMA系统中基于噪声ICA的多用户检测方法

将独立分量分析方法应用于CDMA系统的多用户检测中,针对ICA噪声模型,对噪声分量进行分析,根据修正的牛顿迭代法对ICA算法进行改进,提出一种改进的多用户检测方法。仿真结果表明,改进的噪声ICA多用户检测方法有效地降低了误码率,提高了检测性能。     

应用牛顿迭代法进行水库调洪计算

水库调洪计算的基本原理就是水量平衡方程，由于水库水位和水库下泄流量之间具有函数关系，因此求解水量平衡方程必须进行试算，必须预先确定迭代初值和迭代区间，如果迭代初值和迭代区间选取不当，计算收敛速度就很慢甚至发散，难以满足水库管理高度的要求，针对上述问题，本文提出了水库调洪计算的牛顿迭代法，该方法的特点是夫需计算者预先确定失代初值和迭代区间，并具有很高的计算精度和计算效率，本文还对水库调洪计算的牛顿迭     

基于学习的单幅彩色图像超分辨率重建

为了解决单幅彩色图像超分辨率重建中以最常用的欧几里得最小距离来选择最相似块进行重建可能带来的块效应等视觉效果不佳的问题以及由于训练样本较少可能出现最近邻块和待复原块之间误匹配问题,提出在重构算法中引入权值融合机制。通过最小化局部重建误差来计算K个最近邻域块的重建权数,可提升输出图像的高频成分,有效地改善了图像的全局效果,并且将重建后的高频细节作为训练样本再次进行重建以得到更高的图像峰值信噪比(PSNR)。实验结果表明,取4个最近邻块且加权系数依次分别为0.70、0.20、0.05、0.05时重建出的高频细节相对最完整和丰富。     

对数应变幂次强化本构模型研究

就有限压缩变形规律 ,对阿尔曼西应变和对数应变的适用性作了比较 .以铅的实验数据为例 ,采用对数应变—真应力描述给出了幂次强化本构方程 ,并在此基础上进行了有限元计算分析 .定出最佳回归参数 :强化系数B =10 0 0 ,强化指数n =0 0 6 2 5 2 .使用该方法得到的变形量与理论值非常接近 ,且叠代收敛次数少 ,计算效率高 ,计算过程适用于其他金属材料有限变形的研究     

计算运动学问题中牛顿迭代法的混沌现象

研究了用牛顿迭代法求解机构分析和综合问题的代数方程中的混沌现象。通过迭代函数的分析,初步揭示了利用混沌现象求出方程全部解的机理;提出了确定混沌区内各个解吸引槽边界的二分法,该法具有简单且可以达到很高计算精度的特点。