The Irtysh River is an intemational river partially joining the territories of China, Kazakhstan, and Russia. Cascade reservoirs have been constructed in the upper reaches of the river and their effects on the seasona...The Irtysh River is an intemational river partially joining the territories of China, Kazakhstan, and Russia. Cascade reservoirs have been constructed in the upper reaches of the river and their effects on the seasonal discharge of the middle and lower reaches were analyzed considering the mean and dispersion of the seasonal discharge. The Lepage test, which is a nonparametric, two-sample test for detecting location and dispersion, was used to measure the significance of difference between the pre-dam and post-dam seasonal discharge. The results show that the reservoirs＇ effects on the seasonal discharge varied with the season. In the middle reaches of the river, the summer and autumn discharge decreased significantly and their inter-annual variabilities also decreased significantly. The summer and autumn precipitation over the Irtysh River Basin changed little before and after the operation of the reservoir, which indicates that the discharge changes mainly due to water storage of the reservoirs. The reservoirs store water in summer and autumn and store more water in a wet year, which leads to the reduction of the mean and dispersion of the summer and autumn discharge. The winter discharge increased significantly because the reservoirs released water for power generation. The spring discharge changed slightly. In the lower reaches, only the winter discharge increased significantly, and the other seasonal discharge changed slightly. The reservoirs＇ effects on the seasonal discharge are more significant in the middle reaches than in the lower reaches.展开更多
针对非参数过程的质量控制问题,构建了可以联合监测过程位置参数和尺度参数的Lepage样本统计量,在EWMA图统计量中整合Lepage的历史、当前以及最新差异信息,提出了扩展EWMA-Lepage(EEWMA-Lepage, EEL)控制图及其时变控制限方案(EEL-TV)...针对非参数过程的质量控制问题,构建了可以联合监测过程位置参数和尺度参数的Lepage样本统计量,在EWMA图统计量中整合Lepage的历史、当前以及最新差异信息,提出了扩展EWMA-Lepage(EEWMA-Lepage, EEL)控制图及其时变控制限方案(EEL-TV)和稳态控制限方案(EEL-SS),通过对过程位置与尺度参数的联合监控实现了非参数过程的质量控制。实验结果表明,以过程运行长度的均值、标准差和百分位数作为控制图性能的评价指标,EEL控制图具备对不同过程分布良好的稳健性和对过程参数小漂移比EWMA-Lepage控制图更优的监测性能。Aiming at the problem on quality control of distribution-free process, we propose an extended EWMA (EEWMA-Lepage, EEL) control chart and design its corresponding time-varying scheme (EEL-TV) and steady-state scheme (EEL-SS), through constructing the Lepage sample statistic of joint monitoring on process’ location and scale parameters, integrating the sample history, current and latest difference information into EWMA chart statistic, and joint-monitor the process location and scale parameters to realize the quality control of distribution-free process. The numerical simulation results show that the EEL control chart provides a strong robustness to different process distributions and better monitoring performance on small-shift-monitoring of process parameters than EWMA-Lepage control chart, using the mean, standard deviation and percentiles of process running length as performance-evaluation indexes of control chart.展开更多
基金supported by the Fundamental Research Funds for the Central Universities(Grant No.2013/B13020312)the Ministry of Water Resources’ Special Funds for Scientific Research on Public Causes,for the People’s Republic of China(Grant No.201001052)the Innovative Project of Scientific Research for Postgraduates in Ordinary Universities of Jiangsu Province(Grant No.CXZZ11_0433)
文摘The Irtysh River is an intemational river partially joining the territories of China, Kazakhstan, and Russia. Cascade reservoirs have been constructed in the upper reaches of the river and their effects on the seasonal discharge of the middle and lower reaches were analyzed considering the mean and dispersion of the seasonal discharge. The Lepage test, which is a nonparametric, two-sample test for detecting location and dispersion, was used to measure the significance of difference between the pre-dam and post-dam seasonal discharge. The results show that the reservoirs＇ effects on the seasonal discharge varied with the season. In the middle reaches of the river, the summer and autumn discharge decreased significantly and their inter-annual variabilities also decreased significantly. The summer and autumn precipitation over the Irtysh River Basin changed little before and after the operation of the reservoir, which indicates that the discharge changes mainly due to water storage of the reservoirs. The reservoirs store water in summer and autumn and store more water in a wet year, which leads to the reduction of the mean and dispersion of the summer and autumn discharge. The winter discharge increased significantly because the reservoirs released water for power generation. The spring discharge changed slightly. In the lower reaches, only the winter discharge increased significantly, and the other seasonal discharge changed slightly. The reservoirs＇ effects on the seasonal discharge are more significant in the middle reaches than in the lower reaches.
文摘针对非参数过程的质量控制问题,构建了可以联合监测过程位置参数和尺度参数的Lepage样本统计量,在EWMA图统计量中整合Lepage的历史、当前以及最新差异信息,提出了扩展EWMA-Lepage(EEWMA-Lepage, EEL)控制图及其时变控制限方案(EEL-TV)和稳态控制限方案(EEL-SS),通过对过程位置与尺度参数的联合监控实现了非参数过程的质量控制。实验结果表明,以过程运行长度的均值、标准差和百分位数作为控制图性能的评价指标,EEL控制图具备对不同过程分布良好的稳健性和对过程参数小漂移比EWMA-Lepage控制图更优的监测性能。Aiming at the problem on quality control of distribution-free process, we propose an extended EWMA (EEWMA-Lepage, EEL) control chart and design its corresponding time-varying scheme (EEL-TV) and steady-state scheme (EEL-SS), through constructing the Lepage sample statistic of joint monitoring on process’ location and scale parameters, integrating the sample history, current and latest difference information into EWMA chart statistic, and joint-monitor the process location and scale parameters to realize the quality control of distribution-free process. The numerical simulation results show that the EEL control chart provides a strong robustness to different process distributions and better monitoring performance on small-shift-monitoring of process parameters than EWMA-Lepage control chart, using the mean, standard deviation and percentiles of process running length as performance-evaluation indexes of control chart.
