流程工业在线计量仪表检定周期优化方法

计量技术规范推荐方法在流程工业在线计量仪表检定周期评定中存在不足,提出了一种针对这类仪表的检定周期优化方法。首先,利用Markov状态空间法得到仪表的可用性指标,然后将质量损失函数引入到检定周期寻优目标函数中,从而实现可用性和成本双约束条件下仪表最优检定周期的准确定量计算。最后,以某流程工业企业在线仪表检定周期优化应用为例,验证了该种方法的有效性。     

基于灰色马尔柯夫预测的测量仪器校准间隔动态优化

根据测量仪器校准参数数据特点,建立了仪器校准参数动态发展趋势的时间序列组合模型。将灰色预测与马尔柯夫预测方法优化互补,用灰色预测模型预测参数总体发展趋势,在此基础上采用马尔柯夫模型预测参数在总体趋势下的随机波动性变化,得到校准参数发展趋势预测模型的解。给出基于校准参数趋势预测的校准间隔动态优化方法,并通过实验数据对预测模型进行了验证。结果表明,此模型既能预测校准参数总体趋势,又适合于波动性较大的随机序列变化;校准间隔的优化改善了计量管理中不足计量和过剩计量的缺陷。     

测量仪器校准间隔的模糊范数融合预测

校准间隔的预测是解决测量仪器不足校准和过剩校准的一种主要方法。现有校准间隔预测模型仅仅关注瞬时值,而随机因素的存在导致瞬时值难以精确预测。针对这一问题,在历史校准数据为小样本条件下,提出一种模糊范数融合模型,进行测量仪器校准间隔预测。首先,通过分析历史校准数据的特征和影响因素,建立了校准数据的数学描述模型。在此基础上,采用模糊范数融合模型,预测校准数据的区间。实验表明,模糊范数融合模型更能反映校准数据序列的变化趋势,克服了其它预测模型仅仅预测瞬时值的缺点,提高了预测的可靠性。     

Solid laboratory calibration of a nonimaging spectroradiometer

Field-based nonimaging spectroradiometers are often used in vicarious calibration experiments for airborne or spaceborne imaging spectrometers. The calibration uncertainties associated with these ground measurements contribute substantially to the overall modeling error in radiance- or reflectance-based vicarious calibration experiments. Because of limitations in the radiometric stability of compact field spectroradiometers, vicarious calibration experiments are based primarily on reflectance measurements rather than on radiance measurements. To characterize the overall uncertainty of radiance-based approaches and assess the sources of uncertainty, we carried out a full laboratory calibration. This laboratory calibration of a nonimaging spectroradiometer is based on a measurement plan targeted at achieving a 相似文献   

谈专用测试设备校准规范编写

校准规范是实施校准的基础。编写专用测试设备校准规范是一项非常重要的工作，它是计量保证的基本要求。本文论述了编写组的组成、编写工作程序、校准项目及校准方法、测量标准设备的选择以及校准时间间隔。     

基于新陈代谢GM(1,1)模型的校准间隔预测

针对测量仪器校准间隔的优化问题,根据校准数据非线性、小样本的特点,提出了一种基于新陈代谢GM(1,1)模型的校准间隔预测方法.通过分析历史校准数据的特征,建立了新陈代谢GM(1,1)预测模型,通过仿真实验对预测模型进行了对比验证.结果表明,相对于灰色GM(1,1)模型,新陈代谢GM(1,1)模型克服了随机扰动对系统的影响,更能反映系统的变化趋势,预测精度更高,适合用于测量仪器校准间隔的预测.     

基于分位数函数和Bootstrap分布的不确定度评定研究

最大信息熵方法是基于概率分布评定测量不确度的主要方法之一。其所依赖的高阶矩需要较大样本的测量数据,而校准/检测实验室的测量一般为小样本,故用最大熵方法评定小样本测量不确定度缺乏一定的可靠性。提出了基于分位数函数和概率权重矩作为约束条件的最大信息熵不确定度评定法,把矩的计算从高次降为一次,并结合遗传算法求解概率分布,用Bootstrap分布估计扩展不确定度和包含区间,解决了由分位数区间估计分布不对称所致的复杂计算问题。     

靶标角点自动匹配世界坐标通用算法

为了提高相机标定自动化水平,针对各种样式靶标,提出了一种角点匹配世界坐标的通用算法.分析了影响角点匹配世界坐标的主要因素:镜头畸变和投影变换导致的几何形变.算法利用“区间方差和”搜索极坐标系下最佳投影角,自动选择区间划分方式进行“二次分类”.仿真分析并验证了该算法有效抵抗几何形变和镜头畸变的能力.通过实验验证算法可稳定...     

Calibrating an interferometric laser frequency stabilization to megahertz precision

We report on a calibration procedure that enhances the precision of an interferometer based frequency stabilization by several orders of magnitude. For this purpose, the frequency deviations of the stabilization are measured precisely by means of a frequency comb. This allows us to implement several calibration steps that compensate different systematic errors. The resulting frequency deviation is shown to be less than 5.7?MHz (rms 1.6?MHz) in the whole wavelength interval 750-795?nm. Wide tuning of a stabilized laser at this exceptional precision is demonstrated.     

Kernel Density Estimation-Based Data Correlation

Calibration is the process of identifying and correcting the most likely error in sensor measurements. The basis for the authors' calibration procedure is to construct a statistical error model that captures the characteristics of the measurement errors. Such an error model can be constructed either offline or online and is derived using the nonparametric kernel-density-estimation techniques. Models constructed using various forms of the kernel smoothing functions are compared using statistical evaluation methods. Based on the selected error model, they propose four alternatives to make the transition from the error model to the calibration model, which is represented by piecewise polynomials. In addition, statistical validation and evaluation methods such as resubstitution, is used in order to establish the interval of confidence for both the error model and the calibration model. Traces of the acoustic signal-based distance measurements recorded by infield deployed sensors are used as their demonstrative example. Finally, they discuss the broad range of applications of the error models and provide an example on how adopting statistical error model as the optimization objective impacts the accuracy of the location discovery problem in wireless sensor networks.     

Monitoring the calibration status of a measuring instrument by astochastic model

The paper discusses a class of stochastic models for evaluating the optimal calibration interval in measuring instruments. The model is based on the assumption that the calibration status of a measuring instrument can be monitored by means of one observable parameter. The observable parameter is undergoing a stochastic drift process. The paper introduces and compares stochastic drift models of different nature, and estimates the first passage time of the monitored parameter on a preset limit. The calibration interval is determined as a suitable percentile of the distribution function of the first passage time. A preliminary validation of the model, based on a sample of experimental data collected on a class of instruments, is finally reported     

A Remotely Controlled Calibrator for Chemical Pollutant Measuring-Units

The increasing diffusion of pollutant measuring units, which are installed over wide areas, along with the short calibration interval of several sensors for pollutant quantities, requires new calibration infrastructures to be developed. This paper describes an attempt to develop an innovative calibration system which is based on traveling standards and which does not require units to be removed from the measuring site during the calibration process. The calibration system is based on a traveling standard, which is composed of one or more cylinders that contain gas mixtures, a cell with standard sensors, and a control unit with networking capabilities, which allows the traveling standard to be remotely exercised. A prototype of the proposed system is described and the preliminary results reported.     

Evaluation of Errors in Calibration Procedures for Measurements of Reflection Coefficient

Procedures for the calibration of computer-controlled network analyzers in reflection measurements are studied. The major aim of this paper is to develop an error analysis in order to define a quality factor, for evaluating the performances of a calibration procedure. This is done by using the invariance property of the cross ratio, which easily lets one obtain analytical expressions for the residual errors As an application of this technique, a comparison between two actual calibration procedures has been made using an automatic network analyzer. The experimental results favorably compare with the ones obtained on theoretical basis.     

Empirical likelihood confidence intervals for the endpoint of a distribution function

Estimating the endpoint of a distribution function is of interest in product analysis and predicting the maximum lifetime of an item. In this paper, we propose an empirical likelihood method to construct a confidence interval for the endpoint. A simulation study shows the proposed confidence interval has better coverage accuracy than the normal approximation method, and bootstrap calibration improves the accuracy.     

频率计“时间间隔”参数自动校准的方法研究

主要介绍了利用新研制的通用仪器综合校准系统 ,在实现频率计类仪器“时间间隔”参数自动校准时 ,对相关仪器连接、校准方法以及软件设计等问题 ,提出了一种间接测量单线时间间隔的方法。     

基于微小形变测量的旋翼天平高精度测力校准系统

旋翼天平原位校准中,校准力精确加载是提高校准精度的重要因素。校准装置结构形变会给校准力加载造成误差,影响校准精度。针对这一问题,设计了旋翼天平测力校准系统。该系统采用激光三角法实现微小位移测量,通过测量立方靶块空间位置变化,计算力加载点位移;建立数学模型,分析结构形变对校准力加载影响,测量校准力。经实验,该系统可以消除结构形变影响,准确测量校准力,提高校准力加载精度。     

正弦力校准装置研制

针对现有正弦力校准装置量程无法完全满足动态力校准需求的现状,为了扩展正弦力校准范围,降低动态力的测量不确定度,研制了（2.5～250）kN正弦力校准装置,旨在解决我国动态力溯源体系不完善的问题,并为建立高精度正弦力标准奠定基础。     

Application of an ANFIS Algorithm to Sensor Data Processing

Some sensors require frequent recalibrations; therefore, calibration cost must be limited. In this paper, a new calibration technique is presented. It is a two-phase method which is based on adaptive neuro-fuzzy networks, and it shows superior performances with respect to traditional algorithms, requiring fewer calibration points and less computational power in the recalibration phase. Feasibility has been demonstrated with a pyroelectric biaxial positioning system, reaching performance to the limit of the adopted test bench, on the order of 20 mum with respect to a whole sensible area of 7 mm times 7 mm     

测量仪器校准间隔的确定及其模型

讨论了测量仪器校准间隔的优化及其随机模型，该模型基于如下假设：测量仪器的校准状态可以通过一个观测参数进行监测。中还给出了不同情况下的随机漂移模型，并通过实验数据对随机模型进行了验证。     

现场真空漏孔校准装置的设计

为了减小现场环境与校准环境的差异对真空漏孔校准的影响,通过理论研究,设计了现场真空漏孔校准装置,可实现对真空漏孔的现场校准。考虑到现场真空漏孔校准装置需便于携带及搬运,装置的设计采用了分体式结构。现场真空漏孔校准装置由抽气系统、校准室系统、真空漏孔连接系统、流量输出系统、充气系统、定容室与压力测量系统及烘烤系统等7个部分组成,复合了定容法及固定流导法两种校准方法,预计真空漏孔校准范围为5＆#215;10-10～5＆#215;10-5 Pa？m3/s,合成标准不确定度为10％。