ISO/IEC Guide 98-6:2021 测量不确定度 第6部分：测量模型的开发和使用

标准编号：ISO/IEC Guide 98-6:2021

中文名称：测量不确定度 第6部分：测量模型的开发和使用

英文名称：Uncertainty of measurement — Part 6: Developing and using measurement models

发布日期：2021-02

标准范围

ISO/IEC指南98-6:20 21提供了开发和使用测量模型的指导，还涵盖了测量模型充分性的评估。测量程序、工作说明和文件标准的制定者对该文件特别感兴趣。该模型描述了输出量（被测物）和已知参与测量的输入量之间的关系。该模型用于获得被测物的值和相关的不确定性。测量模型也用于例如设计研究、过程模拟以及工程、研究和开发。本文件解释了如何在测量模型中适应所涉及的数量。这些量涉及i)测量所基于的一种或多种现象，即测量原理，ii)特定测量中产生的效应，以及iii)与待测量的伪影或样品的相互作用水泥。所提供的指导是根据从一开始开发测量模型时可以预期的工作流程来组织的。该工作流程从被测对象的规范开始（第6条）。然后对测量原理进行建模（第7条），并选择适当形式的模型（第8条）。由此获得的基本模型通过识别（条款9）和添加（条款10）由测量和工件或待测量样本产生的影响来扩展。第12条给出了评估所得计量模型充分性的指导。工作流中的基本模型和（完整的）测量模型之间的区别应该有助于那些已经有了测量模型的很大一部分，但希望验证它包含了测量产生的所有影响，以便它适合目的的读者。JCGM 100:2008和JCGM 101:2008中给出了将概率分布分配给测量模型中出现的数量的指南。在第11条中，通过描述如何为此目的开发和使用统计模型来补充本指南。当使用测量模型时，可能会出现数值问题，包括计算效应，如舍入和数值溢出。展示了如何通过以不同的方式表达模型来缓解这些问题，使其在计算中表现良好。还显示了当存在这种依赖性时，有时如何使用模型的重新表述来消除输入量之间的一些相关效应。许多计量学科的示例说明了本文档中提供的指南。

ISO/IEC Guide 98-6:2021 provides guidance on developing and using a measurement model and also covers the assessment of the adequacy of a measurement model. The document is of particular interest to developers of measurement procedures, working instructions and documentary standards. The model describes the relationship between the output quantity (the measurand) and the input quantities known to be involved in the measurement. The model is used to obtain a value for the measurand and an associated uncertainty. Measurement models are also used in, for example, design studies, simulation of processes, and in engineering, research and development.

This document explains how to accommodate in a measurement model the quantities involved. These quantities relate i) to the phenomenon or phenomena on which the measurement is based, that is, the measurement principle, ii) to effects arising in the specific measurement, and iii) to the interaction with the artefact or sample subject to measurement.

The guidance provided is organized in accordance with a work flow that could be contemplated when developing a measurement model from the beginning. This work flow starts with the specification of the measurand (Clause 6). Then the measurement principle is modelled (Clause 7) and an appropriate form of the model is chosen (Clause 8). The basic model thus obtained is extended by identifying (Clause 9) and adding (Clause 10) effects arising from the measurement and the artefact or sample subject to measurement. Guidance on assessing the adequacy of the resulting measurement model is given in Clause 12. The distinction between the basic model and the (complete) measurement model in the work flow should be helpful to those readers who already have a substantial part of the measurement model in place, but would like to verify that it contains all effects arising from the measurement so that it is fit for purpose.

Guidance on the assignment of probability distributions to the quantities appearing in the measurement model is given in JCGM 100:2008 and JCGM 101:2008. In Clause 11, this guidance is supplemented by describing how statistical models can be developed and used for this purpose.

When using a measurement model, numerical problems can arise including computational effects such as rounding and numerical overflow. It is demonstrated how such problems can often be alleviated by expressing a model differently so that it performs well in calculations. It is also shown how a reformulation of the model can sometimes be used to eliminate some correlation effects among the input quantities when such dependencies exist.

Examples from a number of metrology disciplines illustrate the guidance provided in this document.

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