监测Lévy稳定过程均值变点的平均运行时间估计

平均运行长度(时间)(ARL)是判断一控制图监测变点效果好坏的一个重要工具.本文主要研究Lévy稳定过程的均值变点监测问题.我们给出了三个控制图,即EWMA,GEWMA和GLR的ARL估计,并通过数值模拟比较了4个控制图监测均值变点的效果和差异.     

监测L\'{e}vy稳定过程均值变点的平均运行时间估计

平均运行长度(时间) (ARL)是判断一控制图监测变点效果好坏的一个重要工具\bd 本文主要研究L\'{e}vy 稳定过程的均值变点监测问题\bd 我们给出了三个控制图, 即EWMA, GEWMA和GLR的ARL 估计, 并通过数值模拟比较了4个控制图监测均值变点的效果和差异.     

Laboratory Study on Low Gas/Liquid Ratio Foam Flooding for Zhuangxi Heavy Oil

Considering the high cost and injection pressure of conventional foam flooding, foam flooding with low gas/liquid ratio was proposed to enhance the heavy oil recovery. A foamer containing 0.2 wt% α -olefin sulfonate, 0.1 wt% HPAM and 0.5 wt% Na₂CO₃ was selected for Zhuangxi heavy oil. Then the foam stability and low gas/liquid ratio foam flooding were studied via micro model and sand pack experiments. The results indicate that the foam is much more stable in heavy oil than in diesel; in flooding tests, this foamer with gas/liquid ratio of 0.2:1 increases the oil recovery by 39.8%, which is nearly 11% higher than ASP solution in terms of the same injection volume (0.3PV) and agents.     

PLM中误差方差未知时的GLR

本文检验部分线性回归模型(PLM)中,误差的方差未知时,函数部分是否是线性函数,在备择假设下,先用局部多项式方法估计出函数部分,再估计参数部分.计算出了零假设下广义似然比(GLR)检验统计量的表达式,给出了它的渐近分布,并对结果进行了模拟.