Some relationships between gage R&R criteria

In this paper, several commonly used gage repeatability and reproducibility (R&R) acceptance criteria are discussed. The number of distinct categories (ndc) is equivalent to an acceptance criterion based on another standard metric, the ratio of the estimated measurement system standard deviation to the estimated overall standard deviation of the measurements. This implies that the criterion based on ndc could be considered redundant. Several acceptance criteria are revisited and compared, including a discussion of more objective measures of capability based on misclassification rates. The relationship between ndc and the discrimination ratio is also given. Copyright © 2007 John Wiley & Sons, Ltd.     

Gauge capability studies for attribute data

A gauge repeatability and reproducibility (R&R) method is developed to assess the capability of a measurement system. Although gauge capability studies have received substantial attention, few studies have investigated attribute data despite their wide application in industry. The primary aim of this research is to develop a procedure, based on the generalized linear model, to evaluate the R&R of a measurement system for attribute data. To calculate repeatability of a system, the procedure integrates the iterative weighted least squares (IWLS) method and deviance analysis. The proposed procedure is applied to an inclusion measurement system to verify its adequacy to model the process capability. Copyright © 2007 John Wiley & Sons, Ltd.     

测量系统的R&R分析在企业质量改进中的应用

测量系统是指为了完成对被测对象质量特征的测量所需求的人员、量具、程序、软件、操作等的集合。建立准确有效的测量系统永远是企业实现质量改进的第一步。本文阐述了测量系统分析的基本内容及方法，通过一个案例介绍了测量系统分析在企业应用的过程，并提出了应用时的几点注意事项。     

A model‐based approach for attribute gauge analysis

A new method is proposed for the attribute gauge study. A mathematical model based on the Gauge Performance Curve (GPC) is introduced and the connection between the model parameters and gauge characteristics is discussed. The ability of the whole measurement system (the process and the gauge together) is characterized by two key probabilities: the probability of a rejected part being good and the probability of an accepted part being bad. These probabilities can be calculated either with the proposed mathematical model of GPC (GPC‐method) or by using relative frequencies (AIAG‐type method). The performance of the two approaches has been compared, and the proposed GPC‐method is proven to be statistically favourable. Copyright © 2010 John Wiley & Sons, Ltd.     

Random errors caused by temperature in magnitude of principal strains evaluated ith 3-element strain gauge rosettes

The effects of the uncertainties associated ith the apparent strain and gauge factor data, given by the manufacturer, in the evaluation of principal strains are examined. Principal strains are obtained by a reduction of the strains measured ith electrical resistance strain gauge rectangular or delta rosettes. The theoretical analysis points out the relevance of the effects caused.     

Confidence Intervals for Unbalanced Two‐factor Gauge R&R Studies

We consider methods for constructing confidence intervals in a two‐factor gauge repeatability and reproducibility (R&R) study when there are unequal replicates. We consider both random and mixed models and propose a general approach using unweighted sums of squares. Computer simulation is used to determine how well confidence intervals maintain the stated confidence level. The main conclusion is that the method performs well under a variety of conditions typically encountered in gauge R&R studies. The method is simple and the intervals can be computed in a spreadsheet program. Copyright © 2005 John Wiley & Sons, Ltd.     

Development of a Vibrating Wire Strain Gauge for Measuring Small Strains in Concrete Beams

Abstract:  A vibrating wire strain gauge capable of measuring strains in concrete elements to an accuracy of better than 0.5  μ ɛ is presented. This offers some advantages over conventional electrical resistance gauges, the quoted accuracy of which is typically 3  μ ɛ , and which are often considered unsuitable for concrete because of their inability to span cracks. While vibrating wire gauges are potentially more accurate, they are prone to significant errors because of temperature changes. In the purpose-built gauge described here, temperature correction is achieved using an unstrained reference gauge. The vibration data are analysed using a moving-window Fourier transformation in order to identify and remove the geometrically nonlinear portion of the response. The resulting system is accurate, economical and easy to use. The gauges have been used to study the behaviour of cracked concrete specimens. Typical results are presented and discussed.     

高校教学质量评估的属性综合评价模型

根据教师教学质量评估指标体系,按照置信度准则建立高校教学质量评价的属性综合评价模型,运用成对比较矩阵求权向量的特征根法确定了各指标的权重,并将该模型应用于实践,对学校教师教学水平进行了评估。     

基于活塞式压力计和数字压力计的微小压力测量新方法

提出了一种微小表压力（差压）测量的新方法。采用1台活塞式压力计和1台精密的数字压力计,通过关断阀连接高低压端的特殊连接方式实现微小表压力（差压）测量,解决了活塞式压力计由于受其下限值的限制而不能实现微小压力测量的问题。利用数字压力计较好的短期稳定性以及活塞式压力计较低的不确定度,可以实现1~10kPa微小表压（差压）的校准,其校准结果的扩展不确定度为U=2.2Pa（k=2）。     

ARMA模型用于多变量随机过程的数字仿真

本文研究采用ARMA模型对多变量随机过程进行数字仿真问题,导出了将模型的AR和MA参数分开计算的参数确定算法,从而减少了所需求解的联立方程的个数.算例表明,采用由所提出的算法导出的ARMA模型可很好地实现对多变量随机过程的仿真.     

步距规校准装置

利用坐标测量机和激光干涉仪的信号合成技术,构成步距规校准装置,实现多示值标准器的高精度校准.介绍了仪器的构成、原理、软件框图等,并进行了详细的不确定度分析.     

基于随机打印机模型的误差扩散半色调算法

通过把新的随机打印机模型与经典的误差扩散算法结合,以解决误差扩散算法对打印机变形敏感,造成的人工纹理和输出半色调图像质量下降的问题,并提出了一种新的基于随机打印机模型的误差扩散算法,通过实验验证获得了较好的输出质量.     

基于随机模糊集的粗糙集模型

当知识库中的知识模块既是模糊的又是随机得到的,我们定义了基于随机模糊集的粗糙集模型。给出了随机模糊粗糙集的性质。讨论了利用模糊集的下近似和上近似定义的模糊测度和概率模糊测度的关系。     

3等量块校准能力验证方法

本文描述中国实验室国家认可委员会（CNAL）3等量块校准能力验证活动的全过程,对在能力验证活动中出现的问题进行了剖析,并提出量块测量中应注意的几个问题。     

基于高斯混合模型的非高斯随机振动幅值概率密度函数

针对非高斯振动信号的幅值概率密度函数难以用数学模型表述的问题,提出了基于高斯混合模型的非高斯概率密度函数表示方法。首先,基于时域样本信号得到非高斯振动信号的高阶矩估计值。其次,基于高斯随机过程偶次高阶矩之间的定量关系,结合二阶高斯混合模型建立方程组,求解得到混合模型中每个高斯分量的方差和权值。然后,将各高斯分量的权值和方差代入高斯混合模型,得到适用于对称非高斯振动信号的幅值概率密度函数。最后,通过仿真信号和实测振动信号,验证了该方法的有效性和适用性。     

随机振动条件下SMT焊点半经验疲劳寿命累积模型

研究了SMT焊点在随机振动条件下引起的振动疲劳情况,给出了SMT焊点半经验随机振动疲劳寿命累积模型,并通过对某SMT电路板进行随机振动疲劳测试,验证了模型的正确性。     

Optimal Designs for Random Blocks Model Using Corrected Criteria

Many industrial experiments involve random factors. The random blocks model defines a covariance structure in the data, thus generalized least square estimators of the parameters are used, and their covariance matrix is usually computed using the inverse of the generalized least square estimators information matrix. Many optimality criteria are based on this approximation of the covariance matrix. However, this approach underestimates the true covariance matrix of the parameters, and thus, the optimality criteria should be corrected in order to pay attention to the actual covariance. The bias in the estimation of the covariance matrix is negligible (or even null) for many models, and for this reason in those cases, it has no sense to deal with the corrected criteria because of the complexity of the calculations involved. But for some models, the correction does have importance, and thus, the modified criteria should be considered when designing; otherwise, the practitioner may risk to deal with poor designs. Some analytical results are presented for simpler models, and optimal designs taking into account the corrected variance will be computed and compared with those using the traditional approach for more complex models, showing that the loss in efficiency may be very important when the correction for the covariance matrix is ignored. Copyright © 2015 John Wiley & Sons, Ltd.     

CFRP随机孔隙模型及孔隙率超声检测数值模拟

基于炭纤维增强树脂基复合材料(CFRP)随机孔隙模型,提出采用时域有限差分法对CFRP孔隙率超声衰减检测进行数值模拟。针对孔隙率P=0.065%~4.96%,厚度2mm,纤维质量分数69%±3%的多层预浸料热压成型炭纤维单向增强环氧树脂基复合板,进行了数值模拟与实验测试。所得到的CFRP孔隙率与超声衰减系数间关系,在模拟与实验中展现了相似的规律。结果表明:利用随机孔隙模型结合时域有限差分法进行CFRP孔隙率超声检测数值模拟具有可行性。     

金属压延智能式辐射测厚仪的研制

本文介绍能广泛适用于金属带村、薄材压延生产线上无接触式连续测量材料厚度的辐射式测厚仪的研制。该测厚仪利用辐射穿透原理并采用单片机技术完成对测量数据的处理和实现各种特定功能，如厚度的绝对值和偏差值数字显示与输出、偏差量的直流显示与输出、测量状态的自动识别和全自动校正，机内工况的键盘检索等。