For many dam projects in China, the 50-year designed life time is coming to an end. It is urgent to study the theory and method to evaluate the dam service life. In this paper, firstly, the probability theory of fuzzy...For many dam projects in China, the 50-year designed life time is coming to an end. It is urgent to study the theory and method to evaluate the dam service life. In this paper, firstly, the probability theory of fuzzy event and time-varying effect theory are used to analyze the time-variety of various risk factors in the process of dam operations. A method is proposed to quantify the above time-variety and a model to describe the fuzzy time-varying risk probability for the dam structure is also built. Secondly, the information entropy theory is used to analyze the uncertain degree relationship between the characteristic value of membership function and fuzzy risk probability, and a mathematical method is presented to calculate the time-varying risk probability accordingly. Thirdly, the relation mode between time-varying risk probability and service life is discussed. Based on this relation mode and the acceptable risk probability of dams in China, a method is put forward to evaluate and forecast the dam service life. Finally, the proposed theory and method are used to analyze one concrete dam. The dynamic variability and mutation feature of the dam risk probability are analyzed. The remaining service life of this dam is forecasted. The obtained results can provide technology support for the project management department to make treatment measures of engineering and reasonably arrange reinforce cost. The principles in this paper have wide applicability and can be used in risk analysis for slope instability and other fields.展开更多
目的探讨子宫动脉栓塞术（uterine artery embolization,UAE）治疗子宫腺肌病痛经症状的疗效评判时间点。方法选择2007年1月~2014年1月有痛经症状并且经MRI检查诊断为子宫腺肌病的患者59例。使用视觉模拟量表（visual analog scale,VAS...目的探讨子宫动脉栓塞术（uterine artery embolization,UAE）治疗子宫腺肌病痛经症状的疗效评判时间点。方法选择2007年1月~2014年1月有痛经症状并且经MRI检查诊断为子宫腺肌病的患者59例。使用视觉模拟量表（visual analog scale,VAS）评价痛经程度,使用重复测量方差分析和广义估计方程比较UAE术前及术后1、3、6、12个月时痛经情况和有效率。结果 1术前痛经VAS为（8.1±2.5）分,术后1、3、6、12个月痛经VAS分别为（3.7±3.7）分、（3.4±3.2）分、（2.7±3.0）分和（2.9±3.2）分。术后各评判时间点痛经程度对比术前均有下降（P=0.000）。术后3个月较术后1个月略下降,无统计学差异;术后6个月痛经程度明显轻于术后1、3个月,而与术后12个月比较无统计学差异。2术后1、3、6、12个月有效率分别为67.8%（40/59）、71.2%（42/59）、79.7%（47/59）和74.6%（44/59）,各时间点间有效率无明显差异,术后6个月时UAE治疗有效率最高。结论术后6个月时痛经缓解程度达到最高峰后维持稳定,是评价子宫腺肌病UAE术后痛经疗效最佳时间点。展开更多
基金Supported by the National Natural Science Foundation of China(Grant Nos.50809025,50539110,50539010,50539030)the Science and Technology Sup-port Plan(Grant Nos.2008BAB29B03,2006BAC14B03)
文摘For many dam projects in China, the 50-year designed life time is coming to an end. It is urgent to study the theory and method to evaluate the dam service life. In this paper, firstly, the probability theory of fuzzy event and time-varying effect theory are used to analyze the time-variety of various risk factors in the process of dam operations. A method is proposed to quantify the above time-variety and a model to describe the fuzzy time-varying risk probability for the dam structure is also built. Secondly, the information entropy theory is used to analyze the uncertain degree relationship between the characteristic value of membership function and fuzzy risk probability, and a mathematical method is presented to calculate the time-varying risk probability accordingly. Thirdly, the relation mode between time-varying risk probability and service life is discussed. Based on this relation mode and the acceptable risk probability of dams in China, a method is put forward to evaluate and forecast the dam service life. Finally, the proposed theory and method are used to analyze one concrete dam. The dynamic variability and mutation feature of the dam risk probability are analyzed. The remaining service life of this dam is forecasted. The obtained results can provide technology support for the project management department to make treatment measures of engineering and reasonably arrange reinforce cost. The principles in this paper have wide applicability and can be used in risk analysis for slope instability and other fields.
