| 摘要: |
| 大坝监测效应量作为一种随机变量,采用以极值理论为基础的POT(Peaks over Threshold)模型研究监测效应量的监控指标是合适的；但现有的POT模型的阈值确定方法以图形法为主,需要人工判断,主观性和随意性较大,且难以实现计算机自动化识别。通过构建阈值递增序列,计算不同阈值条件下相应的监控指标,然后利用概率论中的“3σ准则”,以监控指标危险值与警戒值的差值趋近于测值序列标准差S作为确定最合理阈值的原则,提出了一种改进的阈值确定方法,并给出了一个验证实例。改进方法理论基础明确,有效地克服了图形法的主观性和随机误差,且能采用计算机程序实现最合理阈值的自动识别,增强了POT模型法拟定大坝安全监控指标的实用性。 |
| 关键词: 监控指标 POT模型 阈值 广义Pareto分布 3σ准则 |
| DOI： |
| 分类号:TV 698 |
| 基金项目: |
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| Determination of Dam Monitoring indexBased on Improved Pot Model |
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TANG Xianqi1, YANG Haiyun2, WU Fan2, HE Jinping1
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1.School of Water Resources and Hydropower Engineering,Wuhan University;2.Electric Power Research Institute of State Grid Fujian Electric Power Co,Ltd Fuzhou
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| Abstract: |
| As the dam monitoring effect quantity is a random variable, the peaks over threshold (POT) model based on the extreme value theory could be adopted to study the monitoring index of the monitoring effect quantity. However, threshold in the existing POT model is determined mainly by the graphic method, which requires manual judgment. As a result, greater subjectivity and randomness are generated, and automatic computer identification is difficult to achieve. In this study, a threshold increment sequence is constructed and the corresponding monitoring index under different threshold is calculated. An improved threshold determination method is then developed based on the "3σ criterion" in probability theory , this is, the most reasonable threshold is selected while the difference value between the dangerous value and the warning value of the monitoring index approaches to the standard deviation S of the measured value sequence. A verification example is presented in the study. The improved method has a clear theoretical foundation and effectively overcomes the subjectivity and random errors of the graphical method. By using computer programs, automatic recognition of the most reasonable threshold can be realized, which enhances the practicability of the POT model method for drawing up dam safety monitoring index. |
| Key words: monitoring index POT model threshold Generalized Pareto Distribution 3σ criterion |
