JJF1059—1999《测量不确定度评定与表示》讨论之二十 单次测量结果中是否就没有A类不确定度

1什么是A类不确定度 对被测量X的估计值x的标准不确定度u（x）的评定,从方法上划分,存在统计方法（称A类评定）和非统计方法（称B类评定）两种。这种划分自1980年国际计量局提出的《不确定度表述建议书INC-1（1980）》以来,一直在国际上沿用至今,并把这两种方法所得到的标准不确定度分别称为A类不确定度和B类不确定度。     

测量不确定度实际应用讲座（二）：测量不确定度的评定方法

本文依据BIPM，IEC，IFCC，ISO，IUPAC，IUPAP，OIML七个国际组织于1993年制定并于1995年修订的“测量不确定度表达指南（GuidetotheExpressionofUncertaintyinMeasarement）”，对测量不确定度的计算和表达方法作一介绍。1．常用术语与定义测量不确定度（uncertaintyofmeasarement）：与测量结果相关联的参数，表征合理地赋予被测量值的分散性。标准不确定度（standarduncertainty）：用标准偏差估计值表示的不确定度。A类标准不确定度（typeAstandarduncertainty）或标准不确定度的A类计算方法（typeAevaluationofstandard…     

测量结果总不确定度在实际工作中的运用

0　概述1 993年国际标准化组织 (ＩＳＯ)、国际电工委员会 (ＩＥＣ)、国际计量局 (ＢＩＰＭ)、国际法制计量组织(ＯＩＭＬ)、国际理论化学与应用化学联合会 (ＩＵＰＡＣ)、国际理论物理与应用物理联合会 (ＩＵＰＡＰ)、国际临床化学联合会 (ＩＦＣＣ)等七个国际组织联合发布《测量不确定度表示指南》 ,采用当前国际通行的观点和方法 ,使涉及测量的技术领域和部门 ,用统一的准则对测量结果及其质量进行评定、表示和比较。我国国家质量技术监督局于 1 999年 1月发布《测量不确定度评定与表示》 ,在各种准确度等级的测量领域推行测量不确定度的…     

测量不确定度理解与应用(二)极差法和贝塞尔法之间的比较

标准不确定度的A类评定定义为：“用对观测列进行统计分析的方法，来评定标准不确定度”。国家计量技术规范JJF1059-1999《测量不确定度评定与表示》中介绍了两种A类评定的方法，贝塞尔法和极差法。     

外标法测定饮用水中无机元素的不确定度评定

自1993年以7个国际组织的名义联合发布《测量不确定度表示指南》（GUM）以来,要求各个通过实验室资质认定及中国合格评定国家认可委员会（CNAS）认可的实验室都需具备评定测量不确定度的能力．也已经有很多文献介绍了不同仪器测定不同元素的不确定度评定步骤。笔者结合评定不确定度的经验。总结出用外标法测定无机类元素的不确定度评定时需考虑的主要因素及主要步骤．并以离子色谱法测定硝酸盐氮的不确定度评定为例．介绍了Excel表格及函数在评定过程中的作用。     

实际计量测试中不确定度评定的一些探讨

本针对在实际测量实践中，对不确定度的评价如何着手，对A，B类不确定度评定的划分，B类评定不确定度的评估，以及在实践中如何通过一些实验及数学处理的方法来处理相关性作了一些探讨。     

0℃～961.78℃范围温度基准的不确定度评定

本文根据《测量不确定度表示指南》的统一准则,重新评定了０℃￣９６１．７８℃范围温度基准的不确定度,以基准银凝固点为例介绍了不确定度的评定方法,并给出温度基准各定义固定点的扩展不确定度及包含因子。     

当前测量不确定度评定中的某些误区

自1991年颁布计量技术规范JJG1027-1991《测量误差及数据处理》以来 ,特别是1993年7个国际组织联合发表《测量不确定度表述导则(GUM)》(这个文献1995年修订全文的中文译文可在《测量不确定度表达百问》一书中找到)以来 ,我国介绍和讨论不确定度评定的文章和书籍逐渐多起来 ,其中也有不少评定的算例。这些出版物对我国计量学界掌握和运用测量不确定度起了极大的推动作用。但个别文章中出现了一些虽非十分重要的趋向 ,本人认为也有必要提出供同行讨论     

测量误差与不确定度评定讲座(六) 测量不确定度的评定

在进行测量不确定度的评定时,首先要确定被测量的最佳估计值;其次评定各输入量的标准不确定度,其评定方法可采用A类评定和B类评定;第三计算合成     

测量不确定度概念的理解

本文以测量误差与测量不确定度的定义解析,了解两者的区别,在概念上加深对测量不确定度的理解;通过介绍测量不确定度A类和B类评定方法的异同点,使检测人员初步认知测量不确定度的评定方法,为今后开展测量不确定度的评定工作打下基础。     

测功机转矩示值误差测量结果的不确定度评定

本文主要根据JJF 1059-1999测量不确定度评定与表示计量技术规范，对测功机转矩示值误差的测量结果进行不确定度评定。通过评定，以此作为对相同情况下的测功装置进行测量不确定度评定的一种模式，以便于今后工作的开展。     

检定立式金属罐容量测量不确定度的研究

本文结合立式金属罐的容量测量实例，详述了标准不确定度的计算及扩展不确定度的获得过程。     

金属材料拉伸试验测试结果不确定度的评定

GB／T228．1—2010标准中修改了评定拉伸试验测量不确定度的方法。通过测定卷板的拉伸性能,对规定总延伸强度和抗拉强度的性能指标进行了测量不确定度评定,分析了不确定度来源,剔除测量结果中的离群值,提供了一种拉伸试验测量结果不确定度评定的可行方法,并对评定过程中的几个问题进行了探讨。     

万分之一电子天平示值误差测量不确定度的评定

本文依据JJG 1036-2008《电子天平》检定规程,对万分之一电子天平示值误差测量不确定度评定进行分析。     

Measurement uncertainty in the determination of total petroleum hydrocarbons (TPH) in soil by GC-FID

In this investigation two methods were used for estimating the measurement uncertainty due to sampling and analysis of petroleum hydrocarbon contaminated soil. Analysis of variance (ANOVA) was used for type A evaluation of the measurement uncertainty. The results showed that the statistical evaluation of measurement uncertainty can be complicated by the log-normality and heteroscedasticity of the data. Although mathematical transformation of raw data is widely suggested for overcoming the discrepancy between data and ANOVA assumptions, its use results in problems with the interpretation of the ANOVA results at the original scale.

The measurement uncertainty was also estimated from the calculated precision equations for sampling and analysis. Comparison of measurement uncertainty values with the equivalent values obtained with ANOVA revealed that ANOVA overestimates the expanded uncertainty at both low and high TPH concentrations. Consequently, correct selection of the statistical analysis method needs comprehensive knowledge of the assumptions and limitations of statistical methods and careful consideration of the special characteristics (distribution, constancy of measurement variance) of the raw data as these may affect the validity of the estimated uncertainty. The expanded uncertainty obtained in this study for the results of TPH determinations with linear measurement precision modelling was moderate, ranging from 21% at a TPH concentration of 895 mg/kg to 9% at a TPH concentration of 10 019 mg/kg. If a single sample taken in a survey is analyzed only once, then the analytical variance contributes the most to the measurement variance, ranging from 68– 80% at a TPH concentration of 100–10 000 mg/kg.     

Estimation procedures and error analysis for inferring the total plutonium (Pu) produced by a graphite-moderated reactor

Graphite isotope ratio method (GIRM) is a technique that uses measurements and computer models to estimate total plutonium (Pu) production in a graphite-moderated reactor. First, isotopic ratios of trace elements in extracted graphite samples from the target reactor are measured. Then, computer models of the reactor relate those ratios to Pu production. Because Pu is controlled under non-proliferation agreements, an estimate of total Pu production is often required, and a declaration of total Pu might need to be verified through GIRM. In some cases, reactor information (such as core dimensions, coolant details, and operating history) are so well documented that computer models can predict total Pu production without the need for measurements. However, in most cases, reactor information is imperfectly known, so a measurement and model-based method such as GIRM is essential. Here, we focus on GIRM's estimation procedure and its associated uncertainty. We illustrate a simulation strategy for a specific reactor that estimates GIRM's uncertainty and determines which inputs contribute most to GIRM's uncertainty, including inputs to the computer models. These models include a “local” code that relates isotopic ratios to the local Pu production, and a “global” code that predicts the Pu production shape over the entire reactor. This predicted shape is included with other 3D basis functions to provide a “hybrid basis set” that is used to fit the local Pu production estimates. The fitted shape can then be integrated over the entire reactor to estimate total Pu production. This GIRM evaluation provides a good example of several techniques of uncertainty analysis and introduces new reasons to fit a function using basis functions in the evaluation of the impact of uncertainty in the true 3D shape.     

Evaluation of Measurement Uncertainty Based on the Propagation of Distributions Using Monte Carlo Simulation

The uncertainty associated with a value of some quantity is widely recognized throughout scientific disciplines as a quantitative measure of the reliability of that value. In addition, measurement uncertainty is increasingly seen as essential in quality assurance for industry. The Guide to the Expression of Uncertainty in Measurement (GUM) provides internationally agreed recommendations for the evaluation of uncertainties. This paper outlines the current situation of uncertainty evaluation in the context of international norms and arrangements. It describes the basic ideas and concepts that underlie the GUM and serves as a brief tutorial on methods for evaluating measurement uncertainty in a manner consistent with the GUM. It recommends an approach to evaluating measurement uncertainty based on the propagation of distributions using Monte Carlo simulation. An example is presented to illustrate Monte Carlo simulation.     

测量不确定度在农药残留分析测试中的应用

本文将对测量不确定度重要性进行阐述和探讨,并对NY/T761-2004农药残留分析结果进行实例分析评价。     

测量不确定度原理及在理化检验中的应用第一讲测量不确定度的基本概念及A类标准不确定度

介绍了测量不确定度原理及在理化检验中的应用。就不确定度的定义、分类、评定步骤和方法、报告与表示、有效位数等问题进行了讨论。并对金属材料拉伸试验结果测量不确定度作了详细评定，以作为在理化检验中应用的一个实例。