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131.
Aiming at the complex mechanical and electrical products quality control and early warning problems, a performance analysis model of control chart, which combines the multivariate Bayesian statistical method with the economic performance analysis is constructed. In the solution model, a FT VSI strategy is used in the multivariate Bayesian control chart. If a small probability of random failure occurs, then a loose sampling scheme is selected. Otherwise, a strict sampling program is applied. To quantify the correlation between the economic and the statistical performance of the multivariate Bayesian control chart, a quality control model based on Monte Carlo simulation is used and the ANOSE (Average Number of Observations to Signals or End of the production run) is taken under different economic parameters, which performs the degree of influence of the statistical performance of the control chart. In addition, the relationship between the quality control cost and the false alarm rate of the multi-Bayesian control chart is explained. Finally, for instance, a multiple quality control process of the automatic transmission of the automobile is used to verify the performance evaluation and optimization of the multivariate FT VSI Bayesian control chart. The results show that the method has a better application. 相似文献
132.
为了提高指数加权移动平均(EWMA)控制图监控效率评价的精确性和全面性,提出用一个质量周期内的平均产品个数替代平均抽样个数来进行控制图的经济性和统计性综合评价,建立了一种基于平均产品长度(APL)的更为精确的EWMA控制图经济统计多目标优化设计模型,并采用具体的算例说明了采用NSGA-Ш算法对该模型进行计算的步骤。最后,用该方法优化设计的EWMA控制图与已有的几种EWMA控制图优化设计进行比较,结果表明:本文提出的经济统计优化设计方法显著优于只考虑经济性能的经济设计和只考虑统计性能的统计设计方案。 相似文献
133.
三辊轧制过程中的大变形有限元分析 总被引:6,自引:0,他引:6
采用基于U.L.法的三维弹塑性大变形有限元分析,创立了孔型函数与产品断面形状设计的一体化分析模型,深入分析了无缝管三辊减径时在近似椭圆孔型约束下单道次轧制时瞬态应变场,在微机工作站上实现了大型有限元分析及图形动态显示,为产品工艺参数和辊面孔型设计提供分析依据。 相似文献
134.
Živković D. Živković Ž. Yonghua L. Chou K. C. 《Journal of Thermal Analysis and Calorimetry》2001,66(3):785-793
Results of the comparative thermodynamic analysis of the Pb-BixMgySbz section (x:y:z=8:1:1, in mole ratio) in the Pb-Bi-Mg-Sb system, obtained experimentally by Oelsen calorimetry and predicted by general solution
model in the temperature range 600–1100 K, are given in this paper.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
135.
常规控制图应用的基本假设是从过程得到的测量值彼此独立,但许多连续型的制造业生产过程(例如化学和制药)往往存在自相关,此时常规控制图容易虚发警报。基于数据的样本自相关函数,本文改进了常规控制图的控制界限,使之适用于自相关过程,并运用常规X-s控制图和本文修正的X控制图对一个实际案例进行了比较分析,结果表明本文修正的X控制图可正确地判断过程是否处于受控状态。 相似文献
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139.
Fiona Faulkner Ailish Hannigan Olivia Fitzmaurice 《International Journal of Mathematical Education in Science & Technology》2013,44(5):648-667
Evidence of deficiencies in basic mathematical skills of beginning undergraduates has been documented worldwide. Many different theories have been set out as to why these declines in mathematical competency levels have occurred over time. One such theory is the widening access to higher education which has resulted in a less mathematically prepared profile of beginning undergraduates than ever before. In response to this situation, the present study details the examination of a range of methods through which a student's mathematical performance in higher education could be predicted at the beginning of their third-level studies. Several statistical prediction methods were examined and the most effective method in predicting students’ mathematical performance was discriminant analysis. The discriminant analysis correctly classified 71.3% of students in terms of mathematics performance. An ability to carry out such a prediction in turn allows for appropriate mathematics remediation to be offered to students predicted to fail third-level mathematics. The results of the prediction of mathematical performance, which was carried out using a database consisting of over 1000 beginning undergraduates over a 3-year period, are detailed in this article along with the implications of such findings to educational policy and practice. 相似文献
140.
建立了DEA和神经网络集成的基础设施投资有效性预测模型。该模型首先应用DEA方法,对我国1993-2007年逐期的基础设施投资效率进行评价,得到了用于基础设施投资有效性预测的基本数据。根据对评价结果的投资有效和无效划分建立预测样本,选择多层感知器神经网络,分别对基础设施的规模有效性和技术有效性进行了预测。结果表明基础设施的投资有效性预测具有可行性,而且通过与RBF神经网络、logistic回归和C-支持向量分类机等方法对比,MLP-NN方法的回应率和反查都具有优势,表明应用DEA-MLP-NN进行有效性预测更为有效。 相似文献