用幂基多项式拟合频向函数的几点技巧

提出了用幂基多项式拟合频响函数的几点技巧。运用幂基多项式和最小二乘法对频响函数拟合的计算公式进行了推导,得到了用于问题求解的线性代数方程组,为改善该方程组系统矩阵的条件数,对频率变量和系数矩阵进行了规范化处理;频率变量被规范化到0＝－1的无量纲正实数区域,两个相关矩阵的每列模长被规范为1。然后用奇异值分解的方法求解该方程组,得到拟合频响函数所用的幂基多项式的系数。最后,根据幂基多项式的系数,求出系统的极点和留数,从而识别出系统的模糊态参数,文中给出了一个悬臂梁模拟算例,结果表明本文算法具有较好的计算精度。     

基于最小截取二乘法的点云数据去噪方法研究

针对点云的去噪,本文提出一种基于最小截取二乘法的点云数据去噪方法,该方法采用最小截取二乘法分段拟合直线,拟合的直线受噪声点的干扰较小,具有较强的鲁棒性。实验结果表明,该算法具有良好的去噪效果,且能保留点云的细节特征。     

飞参数据的野值与故障值的判别研究

航空发动机飞行参数记录系统所记录的数据常常出现野值和故障值.本文提出了一种利用参数自身变化率、相关参数和无关参数分析对比综合方法,借助MATLAB 工具,通过软件设计实现了某型航空发动机所有记录参数的野值和故障值的判别.     

基于DSP的快速谱特征提取方法

通过对向量运算的优化，提出了一种简便快速的多项式曲线拟合方法，并在通用高速数字信号处理器ADSP21060中实现，为实时水声信号的分析提供了有效的手段。     

天线结构参数化有限元分析及其变形反射面的拟合

基于ANSYS软件,以载荷作为变量,对某型天线结构进行参数化有限元分析,将反射面上的节点作为采样点,拟合变形反射面的精确数学方程;将非线性曲面目标函数伪线性化处理,并基于最小二乘法数值迭代方法,确定反应曲面几何方程的各个参数;该方法易于程序化,能有效地指导天线的结构设计.     

最小二乘法在大型吊机工件制造中的应用

本文针对大型吊机工件制造中测量数据的处理要求，基于最小二乘法提出了数据平面拟合和椭圆拟合算法；并根据两种拟合算法开发出一套集数据拟合、查询、存储、误差分析等一体的数据处理软件。场地测量数据表明，该软件完全符合相关工件质量控制的需求。     

用相关系数r判断线性拟合质量的探讨

本文讨论了用最小二乘法进行实验数据处理时，当实验应变量范围一定，应变量标准差一定的情况下，相关系数r随实验次数变化的关系．进而讨论得出，用相关系数判断线性拟合质量不是很合理．     

数据拟合算法分析及C语言实现

数据拟合在很多地方都有应用,主要用来处理实验或观测的原始离散数据。通过拟合可以更好的分析和解释数据。在引用前人的算法基础上,采用正交多项式最小二乘法进行曲线拟合,通过实验对算法进行了分析,并给出了C语言实现的代码。     

The Time of Flight electronics for the PAMELA experiment in space

PAMELA, a cosmic ray telescope, was launched into space on 15th June 2006 from the Baikonur cosmodrome aboard of a Soyuz-U and it is in continuous data tacking since 11 July 2006. The Time of Flight system of the PAMELA telescope allows both to distinguish electrons to antiprotons up to about 2 GeV and to measure the absolute charge of the particle. In order to perform these goals the requested time resolution for the whole ToF system is . To fulfill the detector requirements the read out electronics is been required to have a time resolution better than 60 ps with wide dynamic range for charge measurements. The peculiarity of the developed electronics arises from the need to obtain such a time resolution operating in a satellite environment, which implies low-power consumption, radiation hardness, redundancy and high reliability.     

Estimation of Expected Life in the Presence of an Outlier Observation

Consider a life testing experiment consisting of n items, (n – 1) of which have the same expected life while one of them could have a much longer expected life. The standard estimators based on a homogeneous model if used in such a case, would tend to overestimate and result in a large mean squared error (MSE). The present paper considers (n – 1) items having p.d.f. given by l/σ exp (–x/σ) while the remaining one has p.d.f. α/σ exp (–xα/σ), 0 < < 1. We consider estimators of c by linear combinations of the first few order statistics. An optimal estimator is suggested and its MSE is compared with that of the standard estimators. The cases of n = 3 and 4 are explicitly evaluated.     

Outlier detection in multivariate analytical chemical data

The unreliability of multivariate outlier detection techniques such as Mahalanobis distance and hat matrix leverage has been known in the statistical community for well over a decade. However, only within the past few years has a serious effort been made to introduce robust methods for the detection of multivariate outliers into the chemical literature. Techniques such as the minimum volume ellipsoid (MVE), multivariate trimming (MVT), and M-estimators (e.g., PROP), and others similar to them, such as the minimum covariance determinant (MCD), rely upon algorithms that are difficult to program and may require significant processing times. While MCD and MVE have been shown to be statistically sound, we found MVT unreliable due to the method's use of the Mahalanobis distance measure in its initial step. We examined the performance of MCD and MVT on selected data sets and in simulations and compared the results with two methods of our own devising. Both the proposed resampling by the half-means method and the smallest half-volume method are simple to use, are conceptually clear, and provide results superior to MVT and the current best-performing technique, MCD. Either proposed method is recommended for the detection of multiple outliers in multivariate data.     

Outlier suppression in adaptive filtering through de-emphasis weighting

A de-emphasis weighting approach is used to suppress the effect of outliers in background samples during the formation of a sample covariance matrix. The approach is relevant to a broad range of adaptive filtering techniques. Results from processing simulated and real coherent radar data using de-emphasis weighting are compared with results using no outlier suppression and censored sample matrix inversion pruning methods. De-emphasis techniques are shown to produce the most robust detection performance when outliers are present and are also shown to have minimal performance impact when clutter is homogeneous, that is no outliers present     

过程控制异常值的在线检测方法研究

提出了一种改进输入形式的径向基网络RBFN与自回归隐马尔可夫模型ARHMM相结合的异常数据检测方法,并通过引入核空间概念,用以解决过程工业中大量过程数据要求在线异常检测问题。该方法利用改进的RBF网络在核空间内预测待检测数据值,并根据核空间内的预测值与实际值偏差的大小,利用核ARHMM检测数据异常情况。改进的RBF网络能够方便地引入遗忘因子以及惩罚因子,从而增加算法的鲁棒性,提高检测的准确性。采用核ARHMM检测算法可以直接对数据异常情况作出准确判断,从而避免事先确定检测阈值的问题。通过实验与应用证明了该算法的实用性,与AR模型检测方法比较,该方法更适合于过程数据的异常检测问题。     

飞参数据的应用研究现状及发展趋势

飞参系统记录了飞机飞行过程中的大量参数,这些参数在飞机的研制、试飞、训练、维护和事故调查等方面都有着巨大的应用价值.本文总结了国内外对飞参数据的应用研究现状,在此基础上,探讨了今后我国该领域研究的发展趋势.     

巷道掘进中的爆破参数计算

文中引用巷道掘进中炸药单耗与布孔总数的经验计算公式,结合所在矿区的爆破实践,对经验式进行了简化,为巷道掘进提供了经验。     

飞参数据的应用与发展前景

飞参数据是调查飞行事故的重要依据,随着飞参数据记录系统的发展,飞参数据的应用远远不止如此.目前,飞参数据在飞机研制、试飞、训练、状态监控、视情维修等方面起到十分重要的作用.深入挖掘飞参数据的应用价值,对确保飞行安全,提高部队战斗力起着相当重要的作用.本文总结了国内外飞参数据应用发展现状,分析了飞参数据的发展前景,指出了我国今后在飞参数据方面需要研究的关键技术.     

佩戴头盔模拟飞行8h的飞行耐力试验

目的:测定飞行员长时间(8h)模拟飞行时,佩戴飞行头盔对其飞行耐力的影响,为飞行头盔设计改进和使用提供依据。方法:按受试者佩戴头盔的重量(1.7 kg与2.0 kg)和任务负荷(仅提供影视音乐节目与模拟航线飞行)的不同将试验分为3组,观察记录受试者的主诉和表现。结果:受试者反映的问题,主要是闷热和压痛。为减轻闷热和压痛,受试者不断地调整头盔。闷热、压痛和调整头盔频次与时间进程相关,闷热出现在1h-3h,压痛出现在4-7h。因头盔重量和任务负荷不同,各组受试者的主诉和调整头盔频次有显著性差异。结论:头盔重量以及任务负荷等对飞行耐受能力有重大影响:头盔增重、任务负荷增加,加快了闷热和压痛的生成。频繁地调整头盔是缓解闷热和压痛的主要行为表现。相关测量结果为飞行头盔设计改进和使用提供了重要依据。