The motion of pore water directly influences mechanical properties of soils, which are variable during creep. Accurate description of the evolution of mechanical properties of soils can help to reveal the internal beh...The motion of pore water directly influences mechanical properties of soils, which are variable during creep. Accurate description of the evolution of mechanical properties of soils can help to reveal the internal behavior of pore water. Based on the idea of using the fractional order to reflect mechanical properties of soils, a fractional creep model is proposed by introducing a variable-order fractional operator, and realized on a series of creep responses in soft soils. A comparative analysis illustrates that the evolution of mechanical properties, shown through the simulated results, exactly corresponds to the motion of pore water and the solid skeleton. This demonstrates that the proposed variable-order fractional model can be employed to characterize the evolution of mechanical properties of and the pore water motion in soft soils during creep. It is observed that the fractional order from the proposed model is related to the dissipation rate of pore water pressure.展开更多
The actual state of affairs of Chinese social organizations and the latest theoretical findings on the subject indicate that independence and autonomy are concepts that are interrelated but not fundamentally interchan...The actual state of affairs of Chinese social organizations and the latest theoretical findings on the subject indicate that independence and autonomy are concepts that are interrelated but not fundamentally interchangeable; their actual organizational relationship is complex and varied. Exploration of the relationship between the two concepts is a necessary step in the construction and improvement of a rule-based interpretation of the characteristics of Chinese social organizations. Combining resource dependence theory with the institutional logics perspective enables us to analyze the multiple mechanisms influencing the relationship between independence and autonomy at the organizational level and to test for these mechanisms using a mixed methods research design. Our empirical findings indicate that social organizations gain greater autonomy when they have greater independence from government resources and when they strongly identify, structurally and behaviorally, with classical third sector theory. Organizations＇ behavioral identification can regulate the relationship between independence and autonomy. Further case studies support the value of the above findings. This shows that other mechanisms can often replace, offset or constrain the effects of resource dependence. In the real world, no single fixed theory can cover the independence-autonomy relationship.展开更多
电网中常见的低频振荡包括负阻尼低频振荡和强迫功率振荡,精确有效的低频振荡检测与类型判别对保障电网安全稳定运行十分重要。提出基于四阶混合平均累积量（fourthorder mixed mean cumulant,FOMMC）对角切片的低频振荡检测与类型判别...电网中常见的低频振荡包括负阻尼低频振荡和强迫功率振荡,精确有效的低频振荡检测与类型判别对保障电网安全稳定运行十分重要。提出基于四阶混合平均累积量（fourthorder mixed mean cumulant,FOMMC）对角切片的低频振荡检测与类型判别方法。首先推导两种低频振荡的FOMMC对角切片数学表达式,并据此定义振荡检测指标,以检测低频振荡的发生。然后从高阶统计特征的角度深入对比分析两种低频振荡的FOMMC对角切片,并提出根据FOMMC对角切片的峰度判别低频振荡类型的方法。由于利用了低频振荡FOMMC对角切片与原振荡信号包含振荡模态的一致性和对高斯信号的自然盲性,上述方法不受随机功率波动或量测噪声造成的高斯色噪声的影响,即使在信噪比很低的情况下,仍然能够准确检测低频振荡并正确判别振荡类型。华东电网中的仿真结果验证了所提方法的有效性、准确性和抗噪性。展开更多
基金supported by the Natural Science Foundation of Jiangsu Province of China(Grant No.BK2012810)the Fundamental Research Funds for the Central Universities(Grant No.2009B15114)
文摘The motion of pore water directly influences mechanical properties of soils, which are variable during creep. Accurate description of the evolution of mechanical properties of soils can help to reveal the internal behavior of pore water. Based on the idea of using the fractional order to reflect mechanical properties of soils, a fractional creep model is proposed by introducing a variable-order fractional operator, and realized on a series of creep responses in soft soils. A comparative analysis illustrates that the evolution of mechanical properties, shown through the simulated results, exactly corresponds to the motion of pore water and the solid skeleton. This demonstrates that the proposed variable-order fractional model can be employed to characterize the evolution of mechanical properties of and the pore water motion in soft soils during creep. It is observed that the fractional order from the proposed model is related to the dissipation rate of pore water pressure.
文摘The actual state of affairs of Chinese social organizations and the latest theoretical findings on the subject indicate that independence and autonomy are concepts that are interrelated but not fundamentally interchangeable; their actual organizational relationship is complex and varied. Exploration of the relationship between the two concepts is a necessary step in the construction and improvement of a rule-based interpretation of the characteristics of Chinese social organizations. Combining resource dependence theory with the institutional logics perspective enables us to analyze the multiple mechanisms influencing the relationship between independence and autonomy at the organizational level and to test for these mechanisms using a mixed methods research design. Our empirical findings indicate that social organizations gain greater autonomy when they have greater independence from government resources and when they strongly identify, structurally and behaviorally, with classical third sector theory. Organizations＇ behavioral identification can regulate the relationship between independence and autonomy. Further case studies support the value of the above findings. This shows that other mechanisms can often replace, offset or constrain the effects of resource dependence. In the real world, no single fixed theory can cover the independence-autonomy relationship.
文摘电网中常见的低频振荡包括负阻尼低频振荡和强迫功率振荡,精确有效的低频振荡检测与类型判别对保障电网安全稳定运行十分重要。提出基于四阶混合平均累积量（fourthorder mixed mean cumulant,FOMMC）对角切片的低频振荡检测与类型判别方法。首先推导两种低频振荡的FOMMC对角切片数学表达式,并据此定义振荡检测指标,以检测低频振荡的发生。然后从高阶统计特征的角度深入对比分析两种低频振荡的FOMMC对角切片,并提出根据FOMMC对角切片的峰度判别低频振荡类型的方法。由于利用了低频振荡FOMMC对角切片与原振荡信号包含振荡模态的一致性和对高斯信号的自然盲性,上述方法不受随机功率波动或量测噪声造成的高斯色噪声的影响,即使在信噪比很低的情况下,仍然能够准确检测低频振荡并正确判别振荡类型。华东电网中的仿真结果验证了所提方法的有效性、准确性和抗噪性。
