基于蒙特卡罗法的虚拟仪器测量不确定度应用

本文把蒙特卡罗法应用于虚拟仪器测量不确定度评定中,对今后虚拟仪器精度领域的研究是一个借鉴。对虚拟仪器的测量不确定度进行评定和验证是个极其重要的问题,采用蒙特卡罗法重要思想就是,确定一个统计量,其数学期望正好等于所要求的值,样本方差等于理论方差的估计值。     

数据采集卡采样不确定度的蒙特卡罗评定

在分析数据采集卡的采样不确定度来源的基础上,介绍了基于蒙特卡罗方法执行数据采集卡采样不确定度仿真评定原理。针对具体的PCI-6024E数据采集卡,执行不同采样数和不同输入信号范围时的采样不确定度蒙特卡罗仿真评定,将评定结果与GUM理论评定方法比较,验证所提议评定方法的有效性。     

Calculation of Antenna Pattern Influence on Radiated Emission Measurement Uncertainty

介绍了辐射发射的测量误差,在用蒙特卡罗法(Monte Carlo Method)进行分析时,考虑到了天线方向性图的影响。同时分析了天线在两种特殊情况下对不确定度的影响。     

基于图像的多基站定点交会测量技术

为了评价弹道武器装备的战绩效能,采用三台同步高速相机研究基于图像的多基站定点交会测量技术,构建多基站定点交会测量模型和基于Levenberg-Marquardt算法的多基站标定模型,并充分考虑应用环境、相机同步、相机温漂、成像质量以及标定点定位等引入的误差,通过蒙特卡罗模拟仿真方法对不同作用距离交会测量精度进行仿真分析,仿真实验结果表明,在2 km时各坐标分量测量不确定度均小于0.66 m,在1 km时各坐标分量测量不确定度均小于0.45 m,在500 m时各坐标分量测量不确定度均小于0.28 m,完全满足靶场测量应用要求。     

分光法测量LED颜色的不确定度分析

分析了分光法测试发光二极管(LED)颜色的测量不确定度,着重分析了光谱功率分布测量不确定度和波长不确定度对颜色测量的不确定度影响,给出了几种典型LED的分析结果,结果表明,5%的光谱功率分布测量不确定度和0.5 nm的波长不确定度在一般情况下可以满足精度要求为0.001的LED颜色测量.     

ICP-OES法测定焊料中铅的不确定度评定

对于用电感耦合等离子体-原子发射光谱法(ICP-OES)测定焊料中的金属元素铅含量的不确定度来源进行了分析和计算。测量不确定度主要来源于测量重复性、回收率、试样称量、标准溶液配制、校准曲线拟合和样品体积。依据不确定度评定的步骤,计算得到了各分量标准不确定度及合成标准不确定度。     

基于动态不确定度评定的加权数据融合算法

加权融合算法的AR模型,采用遗忘因子递推最小二乘法估计出测量方差.根据测量方差对单一导航传感器信息进行动态不确定度评定,进而确定组合导航系统的组合不确定度.在满足组合不确定度最小的情况下,利用拉格朗日乘数法进行加权值的求解.通过实例仿真表明该法具有较高的融合精度,对提高组合导航系统的定位精度具有实际意义.     

用内标法在SEM上测定固体颗粒直径

阐述了用内标法在扫描电子显微镜上测定固体颗粒直径的方法﹑实验﹑计算方法和测量不确定度评估。并通过对测量不确定度评估的讨论,认为用内标法在扫描电子显微镜上测量微小物质长度是一种操作方便,可以获得较小的测量不确定度的方法。     

雷达谐波抑制度测量及不确定度评定

结合某大功率雷达谐波抑制度测量实例,优化了测试天线被动对准方法,通过放大器与滤波器组合测量,得到了测量结果。分别使用“测量不确定度表示指南”(GUM)法和自适应蒙特卡洛法(AMCM)建立测量模型, 对测量结果不确定度进行评定,在不确定度来源相同条件下,通过比较95%概率包含区间端点差值,GUM 法未通过AMCM 验证,AMCM 对该项目测量结果不确定度评定有更高的可靠性。     

一种改进的瑞利衰落波形仿真方法

在分析比较了蒙特卡罗法、等距法和等面积法的性能基础上,提出了一种改进的瑞利衰落波形的参数计算方法,该方法是在仿真模型的参数确定之前对取样多普勒频率进行了预处理,即进行多次采样并将采样的均值作为瑞利衰落信道的多普勒系数,仿真数据和图形表明新信道仿真模型在自相关统计特性方面,较原蒙特卡罗方法有较大改善,与等距法和等面积法相比使信道参数具有随机性,不仅可以有效仿真单个瑞利衰落,还可以对多个不相关瑞利衰落进行仿真。     

Sensitivity and uncertainty analysis of Markov-reward models

Markov-reward models are often used to analyze the reliability and performability of computer systems. One difficult problem therein is the quantification of the model parameters. If they are available, e.g., from measurement data collected by manufacturers, they are: (a) generally regarded as confidential; and (b) difficult to access. This paper addresses two ways of dealing with uncertain parameters: (1) sensitivity analysis, and (2) Monte Carlo uncertainty analysis. Sensitivity analysis is relatively fast and cheap but it correctly describes only the local behavior of the model outcome uncertainty as a result of the model parameter uncertainties. When the uncertain parameters are dependent, sensitivity analysis is difficult. The authors extend the classical sensitivity analysis so that the results conform better to those of the Monte Carlo uncertainty analysis. Monte Carlo uncertainty analysis provides a global view. Since it can include parameter dependencies, it is more accurate than sensitivity analysis. By two examples they demonstrate both approaches and illustrate the effects uncertainty and dependence can have     

大尺寸空间角测量系统光轴指向不确定度评定

由于被测对象相距较远,高精度的公共测量基准难以建立,因此大尺寸空间角测量的难度较大。为了解决大尺寸条件下空间角的现场测量问题,提出一种基于惯性基准的大尺寸空间角测量方法。首先,阐述了大尺寸空间角的测量原理并且设计了测量系统。然后,对测量系统中基于二维振镜的光轴指向不确定度进行了研究,重点分析了各类误差对光轴指向不确定度的影响。最后,利用蒙特卡洛仿真对各项误差所引起的光轴指向不确定度进行评定,为光轴跟踪装置的误差分配及其指向精度的现场评估等工作奠定了基础。     

Variance importance of system components by Monte Carlo

The authors present an algorithm to compute variance importance, a measure of uncertainty importance for system components. A simple equation has been derived for the measure, and Monte Carlo simulation is used to obtain numerical estimates. The algorithm overcomes NP-difficulty (non-polynomial difficulty) which exists in earlier methods for computing uncertainty importance, and is simpler, more accurate, and more practical. Moreover, it shows the direct relationship between probabilistic importance and uncertainty importance. An example illustrates the evaluation of Monte Carlo variance importance for a sample system     

Modeling secondary electron images for linewidth measurement by critical dimension scanning electron microscopy

Modeling of critical dimensions scanning electron microscopy with sub-nanometer uncertainty is required to provide a metrics and to avoid yield loss in the processing of advanced CMOS technologies. In this paper, a new approach is proposed, which includes a new Monte Carlo scheme, a new Monte Carlo code, as well as the coupling with electrostatic fields to take into account self-charging effects.     

The effect of collisional broadening on Monte Carlo simulations of high-field transport in semiconductor devices

Some important consequences of the uncertainty principle on Monte Carlo simulations of very high field transport are discussed. It is shown that recent values of the phonon scattering rates reported for GaAs by Shichijo and Hess lead to an unrealistically high collisional broadening (0.3-0.6eV) of the electronic states, thus rendering questionable any attempt to relate transport properties to the band structure, and invalidating the semiclassical Boltzmann transport picture used in the Monte Carlo simulation. These considerations are important in the modeling of very high field transport properties in semiconductor devices.     

Statistical Model for the Circuit Bandwidth Dependence of Low-Frequency Noise in Deep-Submicrometer MOSFETs

This paper covers measurement, analytical analysis, and Monte Carlo simulation of the frequency and bandwidth dependence of MOSFET low-frequency (LF) noise behavior. The model is based on microscopic device physics parameters, which cause statistical variation in the LF noise behavior of individual devices. Analytical equations for the statistical parameters are provided. The analytical model is compared to experimental data and Monte Carlo simulation results     

Monte Carlo calculation and measurement of shot-noise reduction factor

The frequency characteristic of the shot-noise reduction factor (R²) of the "O"-type diode is investigated by three methods: the first is a Monte Carlo calculation following the approach of Tien and Moshman and changing the pseudorandom numbers; the second is a computer simulation of the reduction of the modulated electrons at the potential minimum; and the third is the experimental measurement of shot-noise reduction using photoemission electrons produced by a mode-locked ruby laser. It is found by the Monte Carlo calculation that the original results of Tien and Moshman are not characteristic of the general situation, especially with regard to the peak at the plasma frequency of the potential minimum, and with regard to the dip commonly called the Tien dip. Calculations of the shot-noise reduction factor both by the Monte Carlo method and by the computer simulation approach show a rather smooth high-pass frequency characteristic. This result is verified by the photoemission experiments where the measurement accuracy has been enhanced through the use of mode locking.     

QPSK相关检测系统蒙特卡罗仿真及其性能

根据蒙特卡罗仿真方法基本思想，分析了加性高斯噪声和单频干扰条件下的QPSK信号相位分布模型及其相关检测方法；讨论了加性噪声和单频干扰模型，建立了相关检测系统蒙特卡罗仿真模型，模型通过动态系统仿真软件SystemView的二次开发方法实现；进行了仿真电路设计与应用系统性能分析。     

纳米结构器件材料结构参数的新测试方法

使用ＭｏｎｔｅＣａｒｌｏ模拟方法和器件振荡特性测试研究了异质谷间转移电子器件的直流隧穿特性和射频振荡性能与器件结构参数之间的关系．理论计算结果与实验数据间吻合得很好．在此基础上提出了通过电性能测试来分析器件结构参数的新方法．使用逐层化学腐蚀Ｃ－Ｖ测试测定了有源层的掺杂分布．通过低场电阻测量确定了量子阱的宽度．最后从器件振荡特性与ＭｏｎｔｅＣａｒｌｏ模拟曲线的对照中得出了掺杂接口的浓度．由此建立了器件结构参数的一套完整的测试分析方法．使用这套测试监控方法,已成功地研制出ＭＢＥ和ＭＯＣＶＤ工艺的高效、大功率振