Uncertainty-based internal quality control. Harmonization considerations

Three main quality aspects for analytical laboratories are internal method validation, internal quality control (IQC), and sample result uncertainty. Unfortunately, in the past they have been used in a nonharmonized way. The most universal IQC tool is the mean chart, but some criteria used to fix their control limits do not fit the real nature of analytical results. A new approach for fixing these limits is proposed (the u-approach). The key is the combined uncertainty, u, obtained from the method validation information, also used for estimating the sample result uncertainty. A comparative study on "in-control" simulated, bibliographic, and real laboratory data suggests that the u-approach is more reliable than other well-established criteria. In addition, the u-approach mean chart emerges as an IQC tool, consistent with chemical assays, which harmonizes the validation-control-uncertainty process.     

Study on quality control parameters of a TLD system for individual monitoring

This work intends to identify and follow up quality control parameters important for the general improvement of our thermoluminescence dosemeter (TLD) system for Individual Monitoring that is currently preparing its accreditation according to the EN ISO/IEC 17025 Standard. A retrospective analysis of the readers' start-up tests revealed an eventual variation of parameters, like the high voltage, which may affect the light collecting system, and hence the TL dose results. This was investigated and although the high voltage requires a careful look, the stability and reproducibility of the TLD system was ascertained by the results of quality control procedures. As a consequence of this work, the start-up procedure was modified and the warning levels used for the start-up daily tests of the readers were derived from a more realistic approach.     

计量技术机构检测质量控制技术的方法

通过对计量技术机构检测质量的影响要素分析及要素间的关联性研究,梳理出使质量管理工作系统化、流程化及闭环运行的工作思路,并使用计算机信息化技术,将计量技术机构体系管理全方位纳入管理信息系统,有效覆盖各个管理要素。     

Harmonization of internal dosimetry procedures in Latin America--ARCAL/IAEA project

Under the auspices of the Regional Coordination Agreement for Latin America, representatives of the eight member states have participated in a project to improve radiological protection for workers exposed to unsealed sources of radiation. The design of the project was based on information obtained from a questionnaire circulated among the participants, from which the initial status of internal dosimetry services in each country was characterised. The objective of the project is to harmonize internal dosimetry procedures, with reference to International Atomic Energy Agency recommendations. After the implementation of new procedures and personnel training, four intercomparison exercises were carried out: measurement of iodine in thyroid phantoms, measurement of gamma emitters in urine samples, measurement of beta emitters in urine samples and internal dose assessments. This project has resulted in important improvements in internal dosimetry services in the region.     

SNT-TC-1A within a UK quality assurance system

Training and certification of ndt personnel is discussed within the framework of an overall system of quality assurance in industry. The authors argue that SNT-TC-1A, a Recommended Practice for inspection and testing with guidelines laid down by ASNT, should be integrated into the quality system of individual companies to assure customers of the quality of inspection personnel. The requirements of SNT-TC-1A are outlined and compared with other operator certification schemes.     

Contributions of metrology to production quality

Conclusions The contribution of metrology to production quality is an involved problem that requires the attention of designers, technologists, metrologists, etc. Clarification of its basic meaning is an urgent matter as its solution uniquely defines the range of topics that have a direct bearing on production quality. In turn, the knowledge of these topics makes it possible to impart strict purposefulness to and improve the efficiency of all actions of all the different technical services, including the metrological one, in ensuring the production of goods of excellent quality only.Translated from Izmeritel'naya Tekhnika, No. 2, pp. 10–13, February, 1972.     

Harmonization of SNT-TC-1A and BS 5750 to create a quality system for the qualification of NDT personnel

Throughout the UK, and internationally, companies are seeing advantages in the establishment of a written system for the training and examination of their NDT personnel. Indeed, this is a requirement of the British Standard on quality systems (BS 5750) which states that:The supplier shall establish a system for identifying training needs and certification requirements for all contracting, design, manufacturing, installation and quality assurance functions that would be adversely affected by lack of such training. All personnel performing such functions shall have the appropriate experience or training^[1].In this article the authors argue that SNT-TC-1A^[2] may be used to establish such a system with confidence.     

Monte Carlo dosimetry for targeted irradiation of individual cells using a microbeam facility

Microbeam facilities provide a unique opportunity to investigatethe effects of ionising radiation on living biological cellswith a precise control of the delivered dose. This paper describesdosimetry calculations performed at the single-cell level inthe microbeam irradiation facility available at the Centre d'EtudesNucléaires de Bordeaux-Gradignan in France, using theobject-oriented Geant4 Monte Carlo simulation toolkit. The cellgeometry model is based on high-resolution three-dimensionalvoxelised phantoms of a human keratinocyte (HaCaT) cell line.Such phantoms are built from confocal microscopy imaging andfrom ion beam chemical elemental analysis. Results are presentedfor single-cell irradiation with 3 MeV incident alpha particles.     

小区间参数不确定性高阶系统的振动控制研究

针对复杂高阶不确定性系统的鲁棒H∞振动控制难题,基于小区间参数不确定性系统降阶方法的研究,系统地给出了包含降阶对象的构建、不确定性系统的降阶、鲁棒控制器的求解以及鲁棒性验证等在内的一整套研究策略和分析方法。为保障整个分析和求解过程的顺利进行,分析了高阶矩阵指数函数一阶偏导数求解困难的根源以及利用数值微分法的解决策略,并给出了一类维数较小的不确定性矩阵分解方法。最后通过算例表明了整个分析过程和求解方法的合理性和可行性。     

Performance characteristics of a composite multivariate quality control system.

We present the results of an evaluation of the performance characteristics of a composite multivariate quality control (CMQC) system that incorporates quality control rules for univariate, multivariate, and correlation conditions. The CMQC system evaluated is designed to help analysts detect unacceptable trends and systematic error in one or more variables, unacceptable random error in one or more variables, and unacceptable changes in the correlation structure of any pair of variables. It is also designed to be tolerant of missing data, to allow analysts to reject as few as one or as many as all variables in a run, and to provide analysts with control statistics and graphics that logically relate to sources of analytical error. We show that the various components of the CMQC system have adequate statistical power to detect systematic errors, random errors, and correlation changes under the conditions likely to be encountered with multivariate analytical measurement systems: (1) a single variable with increased systematic or random error; (2) all variables or a subgroup of variables affected by a common problem that increases systematic or random error; and (3) missing data for one or more variables in a run. We also show that the power of the multivariate component of the CMQC system to detect systematic and random errors is higher than the power of an alternative multivariate test criterion.     

Radiophotoluminescence dosimetry using a small spherical glass: a preliminary phantom study

A radiophotoluminescence dosimetry has been proposed using a spherical silver-activated phosphate glass with a diameter of 1.5 mm. A 6 MV photon dose of 2 Sv (2 Gy) was delivered to 14 spherical glass samples placed between two solid water phantoms at a depth of 10 cm. The samples were positioned within a 20 x 20 mm(2) centred at beam axis to ensure uniform dose absorption. A normalised output from a read-out system was obtained by simultaneously measuring luminescence from a non-irradiated reference and that from an irradiated reference to eliminate background contamination and time-varying fluctuation of the readout system, leading to a normalised standard deviation of 1.8%. A dose up to 3.5 Sv (3.5 Gy) was delivered to three spherical glass samples positioned between two solid water phantoms at a depth of 10 cm. The normalised output increased linearly with the applied dose.     

Method for obtaining gas concentration with a phase-based metrology system

A new technique is presented for obtaining gas concentration by measuring the slope of the anomalous dispersion at a resonance. We describe the equations that govern this process using a Lorentz model and show that the slope of the anomalous dispersion is directly related to the absorption coefficient. The slope is obtained from an interferometric setup and a frequency modulation spectroscopy technique. Experimental data are presented that illustrate this technique for two different sample cells containing water vapor.     

Composite multivariate quality control using a system of univariate, bivariate, and multivariate quality control rules.

We propose a composite multivariate quality control (CMQC) system to control simultaneously measured variables. This system is designed to detect unacceptable trends and systematic error in one or more variables, unacceptable random error in one or more variables, and unacceptable changes in the correlation structure in any pair of variables. It is also designed to be tolerant of missing data, to be capable of rejecting as few as one or as many as all variables in a run, and to provide the analyst with control statistics and graphics that logically relate to sources of analytical error. Quality control rules for univariate, multivariate, and correlation conditions are incorporated in the system, as are plots displaying CMQC statistic values and control limits for univariate, multivariate, and correlation parameters. We also discuss advantages of the CMQC over the T2 and principal component multivariate quality control methods. We demonstrate the CMQC procedure using data from a laboratory process in which 40 variables were measured during 40 characterization runs and 23 runs analyzing unknowns.     

信息系统的测试与质量控制

根据信息系统质量控制的目标任务,结合实际案例,对其代码级漏洞测试、功能测试、性能测试、问题定位、回归测试和文档评审的测试方法进行描述。使人们了解信息系统的测试方法,并且对信息系统的质量控制有所重视。     

QS 9000质量体系与产品设计质量控制

ＱＳ 90 0 0质量体系标准是美国福特、通用和克莱斯勒三大汽车公司 (以下简称三大公司 )在ＩＳＯ 90 0 0标准的基础上联合推出的质量标准 ,受到国际汽车界的广泛重视 ,因此 ,初步了解ＱＳ 90 0 0有关产品设计方面的标准 ,对提高产品设计素质 ,规范产品设计开发活动大有益处 ,并有益于ＧＢ 190 0 0的宣贯和认证工作的开展。1 ＱＳ 90 0 0质量体系与ＩＳＯ 90 0 0ＩＳＯ 90 0 0的推出 ,受到国际社会各行业的普遍认可 ,美国三大公司为了全球战略的需要 ,在ＩＳＯ 90 0 0的基础上协调一致 ,携手推出了ＱＳ 90 0 0质量体系。其目的是针对三大公…     

小区域高精度实时三维声源定位系统

设计了一个基于AT89S52单片机的适用于低频(20Hz～2000Hz)、小区域的高精度实时三维声源定位系统。该系统包括三个模块:声源采集和模数转换模块;时间延迟采集模块;串口通信和定位算法模块。在1000m3范围内,根据该系统可以实时快速地定位出三维空间声源的位置,且定位最大水平偏向角误差为±0.3°,最大俯仰角误差为±0.5°。