Ultrahigh-performance FFTs for the CRAY-2 and CRAY Y-MP supercomputers

In this paper a set of techniques for improving the performance of the fast Fourier transform (FFT) algorithm on modern vector-oriented supercomputers is presented. Single-processor FFT implementations based on these techniques are developed for the CRAY-2 and the CRAY Y-MP, and it is shown that they achieve higher performance than previously measured on these machines. The techniques include (1) using gather/scatter operations to maintain optimum length vectors throughout all stages of small-to medium-sized FFTs, (2) using efficient radix-8 and radix-16 inner loops, which allow a large number of vector loads/stores to be overlapped, and (3) prefetching twiddle factors as vectors so that on the CRAY-2 they can later be fetched from local memory in parallel with common memory accesses. Performance results for Fortran implementations using these techniques demonstrate that they are faster than Cray's library FFT routine CFFT2. The actual speedups obtained, which depend on the size of the FFT being computed and the supercomputer being used, range from about 5 to over 300%.     

鱼雷质心配重纠偏技术的实现

为了快速找到最佳配重组合，使鱼雷在完成配重后的实际质心尽可能地接受理想位置，提出了实际质心矢量和配重矢量的概念，从而将静力学问题转化为相对容易处理的几何学问题。设计了配重矢量表，通过查表法可以快速地寻求最佳配重组合，并提出了最大配重误差的评价方法。     

基于LVQ网络在轴承座松动故障诊断中的应用

把汽轮机轴承座松动的相关频段上不同频率谱的谱峰能量值作为故障信号的训练样本输入到LVQ网络中去，并由LVQ网络产生训练后不同的权重向量。由于竞争层神经元的权重分布不同，则权重分布图也不同，可根据不同的权重分布图来确认和诊断汽轮机轴承座松动故障的不同程度。     

基于径向矢量的不变性形状分类方法

介绍一种利用径向矢量提取形状特征的方法，着重于分析二维图形的不变性，提出一种带有方向因子的径向矢量描述，该矢量以图形边界弧长为自变量，完整地刻画了图形特点，克服了非凸图形识别中存在的多义性，以归一化的特征矢量的输入，采用三层神经网络为分类器，在字符及军事目标不变性识别中取得了令人满意的结果。     

依缓冲库调速CIMS可靠性分析的位相结构方法

本文提出了依缓冲库调速ＣＩＭＳ可靠性分析的位相结构方法，从闭环排队网络出发，利用准生灭过程理论，给出了系统的各种可靠性指标和生产指标，讨论了系统局部运行期的们相特征，最后给出了两个数据算例。     

Linear variational principle for convex vector maximization

For infinitely dimensional convex vector maximization problems, it is proved that there exists, under certain conditions, an arbitrarily small additive perturbation of the performance criterion by a linear continuous operator such that the perturbed problem has efficient solutions. The study was sponsored by the Ukrainian State Fund for Basic Research __________ Translated from Kibernetika i Sistemnyi Analiz, No. 2, pp. 105–114, March–April 2007.     

Comparative study on adaptive rational macromodels of highly resonant structures

Two macromodeling techniques using rational bases are investigated to accurately predict the natural frequencies of highly resonant microwave structures. Three methods are proposed and compared to calculate pole‐free solutions to the Thiele continued fraction and vector fitting pole‐residue models of the characteristic equation det[Z(s)]. © 2007 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2007.     

Two-class fingerprint matcher

We present a system for fingerprint verification that approaches the problem as a two-class pattern recognition problem. The features extracted by “FingerCode” are used to capture the ridge strength. This feature vector is then classified as genuine or impostor according to a novel approach to handle the fingerprint verification as a two-class problem. Moreover, we show that extracting the features from sub-images around the core permits to better represent the local information.