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131.
The definition of an assigned value is usually achieved by calculating mean values from the data (with different methods)
or by designating reference laboratories. Neither method is completely satisfactory. In this paper a new method is presented
for the definition of the assigned value for spiked samples with an unknown content of the analyte in the matrix. The method
consists of two parts. The first is the estimation of the assigned values from the spiked amounts and the content in the matrix,
based on the results of reference laboratories. The other is the designation of these reference laboratories by comparing
their results with the assigned values. Because each of these parts requires the other, an iterative procedure is necessary.
As an example, the results of a proficiency test for the analysis of copper in wastewater are used to compare the calculated
values with those from other methods, e.g., the Huber estimation.
Received: 25 September 2000 Accepted: 9 December 2000 相似文献
132.
刀口定量检验技术的研究 总被引:5,自引:0,他引:5
主要介绍了天文镜面加工的中的刀口定量检验技术,包括阴影图像CCD实时采集,图像处理,定量计算。 相似文献
133.
Adriaan M. H. van der Veen Thomas P. J. Linsinger Andree Lamberty Jean Pauwels 《Accreditation and quality assurance》2001,6(6):257-263
To serve as a measurement standard, a (certified) reference material must be stable. For this purpose, the material should
undergo stability testing after it has been prepared. This paper looks at the statistical aspects of stability testing. Essentially,
these studies can be described with analysis of variance statistics, including variant regression analysis. The latter is
used in practice for both trend analysis and for the development of expressions for extrapolations. Extrapolation of stability
data is briefly touched upon, as far as the combined standard uncertainty of the reference material is concerned. There are
different options to validate the extrapolations made from initial stability studies, and some of them might influence the
uncertainty of the reference material and/or the shelf-life. The latter is the more commonly observed consequence of what
is called ’stability monitoring’.
Received: 6 October 2000 Accepted: 4 December 2000 相似文献
134.
The different approaches that have been taken in the development of analytical methods for the determination of nitrate within the field are reviewed. The emphasis has been placed on providing a critical appraisal of the chemistry that underpins current commercial systems and the need to remove the dependence on heavy metal and concentrated acid components. The search for more environmentally acceptable and user friendly systems has long been pursued and the present communication seeks to explore the recent development in portable testing technologies and how they might evolve in the future. In particular, the role of electrochemical techniques in the latter are investigated and their potential application compared and contrasted with the more traditional wet chemical detection strategies. 相似文献
135.
136.
本文提出利用衍射光栅的反射特性,在自光图像处理系统中对光栅进行实时无损伤检验.这种方法灵敏度高、简便易行,有较高的实用价值.理论与实验结果一致. 相似文献
137.
Paola Fisicaro Soraya Amarouche Béatrice Lalere Guillaume Labarraque Marc Priel 《Accreditation and quality assurance》2008,13(7):361-366
Since the advent of the Guide to the Expression of Uncertainty in Measurement (GUM) founding the principles of uncertainty
evaluation, numerous projects have been carried out to develop alternative practical methods when it is impossible to model
technical or economical aspects of the measurement process. These methods can use all the experimental data available to the
laboratories, such as repeatability, reproducibility, quality-control charts, etc. The studies presented in this paper compare
the results obtained by the modelling method from GUM with the uncertainties found by applying alternative methods. They show
two examples, one in the field of environmental monitoring, the other in the biomedical field, based on the exploitation of
PT schemes results.
Presented at BERM-11, October 2007, Tsukuba, Japan. 相似文献
138.
Yoshito Mitani Judith Velina Lara-Manzano Aaron Rodriguez-Lopez 《Accreditation and quality assurance》2008,13(7):421-426
According to the experience of the successful implementation of proficiency tests (PT) by using the certified reference value
as the assigned value, a new scheme of evaluation is presented by suggesting the use of the uncertainty associated with the
certified value. The technical performance of laboratories is evaluated by the parameter quadratic mean error (QME), which
is the square root of the sum of the square of the bias and that of the standard deviation of the laboratory. This parameter
is considered as the estimate of the measurement uncertainty of the laboratory and is compared to the uncertainty (U) associated with the certified value provided by an NMI. Considering that the calibration and measurement capability, known
as the CMC, is recognized among NMIs, the ratio QME/U enables us to compare the PT relative to the CMC of an NMI, and, consequently, to any other comparison results based on the
CMC of signatories of the mutual recognition arrangement (MRA) of the International Committee of Weights and Measure (CIPM).
Presented at BERM-11, October 2007, Tsukuba, Japan. 相似文献
139.
We study a CUSUM–type monitoring scheme designed to sequentially detect changes in the regression parameter of an underlying
linear model. The test statistic used is based on recursive residuals. Main aim of this paper is to derive the limiting extreme
value distribution under the null hypothesis of structural stability. The model assumptions are flexible enough to include
rather general classes of error sequences such as augmented GARCH(1,1) processes. The result is underlined by an illustrative
simulation study.
Research partially supported by NSF grants DMS–0604670 and DMS–065242. 相似文献
140.
We consider the problem of monotonicity testing over graph products. Monotonicity testing is one of the central problems studied in the field of property testing. We present a testing approach that enables us to use known monotonicity testers for given graphs G1, G2, to test monotonicity over their product G1 × G2. Such an approach of reducing monotonicity testing over a graph product to monotonicity testing over the original graphs, has been previously used in the special case of monotonicity testing over [n]d for a limited type of testers; in this article, we show that this approach can be applied to allow modular design of testers in many interesting cases: this approach works whenever the functions are boolean, and also in certain cases for functions with a general range. We demonstrate the usefulness of our results by showing how a careful use of this approach improves the query complexity of known testers. Specifically, based on our results, we provide a new analysis for the known tester for [n]d which significantly improves its query complexity analysis in the low‐dimensional case. For example, when d = O(1), we reduce the best known query complexity from O(log 2n/ε) to O(log n/ε). © 2008 Wiley Periodicals, Inc. Random Struct. Alg., 2008 相似文献