Top-down approach for the estimation of measurement uncertainty based on quality control data and grey system theory

摘要

Uncertainty is the scientific representation of the quality level and dispersion of measured results. Considering the problems with the current classical uncertainty evaluation method (namely, the GUM method), such as the repeated evaluation, omission and difficulties in quantifying uncertainty components, a 'top-down' approach represented by the control chart method is proposed, using the intermediate precision standard deviation of laboratory quality control data accumulated over a long period of time to indicate measurement uncertainty. Based on the principle of the 'top-down' approach, a new evaluation method for the measurement uncertainty of laboratory quality control data is proposed here, which use the standard deviation defined by grey system theory to indicate uncertainty (abbreviated as quality control - grey method). Furthermore, we have evaluated the measurement uncertainty of hydrogen in titanium using the quality control - grey system theory method, based on quality control data according to the inert gas fusion thermal conductivity method in the laboratory. The results achieved are 12.6 +/- 4.0 mu g x g(-1), k = 2, which is consistent with the value of 12.6 +/- 3.5 mu g x g(-1), k = 2, evaluated by the quality control chart method. The quality control-grey evaluation method developed a top-down uncertainty estimate approach and provides a new idea and tool for physical and chemical laboratories to evaluate measurement uncertainty using quality control data that has been accumulated.