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Research on seasonal correlation of wavelet packet energy spectrum and temperature of Runyang Suspension Bridge

Science China(Technological Sciences) 2009年第6期52卷 1776-1785页

作者： YouLiang Ding AiQun Li Jun Sun Yang Deng School of Civil Engineering Southeast University Nanjing 210096 China

In order to establish an environmental-condition-normalized structural damage alarming method, the seasonal correlation analysis of wavelet packet energy spectrum (WPES) and temperature of Runyang Suspension Bridge is performed by means of the 236-day health monitoring data. The analysis results reveal that the measured WPES has remarkable seasonal correlation with the environmental temperature. The seasonal change of environmental temperature accounts for the variation of the damage alarming parameter I p of the dominant frequency bands with an averaged variance of 200%. The statistical modeling technique using a 6th-order polynomial is adopted to formulate the correlation between the WPES and temperature, on the basis of which the abnormal changes of measured damage alarming parameter I p are detected using the mean value control chart. It is found that the proposed method can effectively eliminate temperature complications from the time series of WPES and exhibit good capability for detecting the damage-induced 10% variances of the damage alarming parameter I p . And the proposed WPES-based method is superior the modal frequency and hence is more suitable for online real-time damage alarming for long-span bridges.

关键词： structural damage alarming wavelet packet energy spectrum wavelet packet analysis temperature seasonal correlation suspension bridge

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Environmental variability study on the measured responses of Runyang Cablestayed Bridge using wavelet packet analysis

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Science China(Technological Sciences) 2008年第5期51卷 517-528页

作者： DING YouLiang LI AiQun LIU Tao College of Civil Engineering Southeast UniversityNanjing 210096China

The structural damage alarming method based on wavelet packet energy spectrum (WPES) for long-span cable-stayed bridges is presented through combination of ambient vibration test and wavelet packet analysis. The environmental variability in the measured WPES and damage alarming indices ERVD of the Runyang Cable-stayed Bridge are discussed in detail using the wavelet packet analysis of the measured acceleration responses of the bridge under daily environmental conditions. The analysis results reveal that the actual environmental conditions including traffic loadings, environmental temperature and typhoon loadings have remarkable correlations with the measured WPES. The changes of environmental temperature have a long-term trend influence on the WPES, while the influences of traffic and typhoon loadings on the measured WPES of the bridge present instantaneous changes because of the nonstationary properties of the loadings. The analysis results of the measured responses further reveal that the damage alarming indices ERVD can sensitively reflect the influences of environmental temperature and typhoon loadings on the dynamic properties of Runyang Cable-stayed Bridge. Therefore, the proposed structural damage alarming indices ERVD under ambient vibrations are suitable for real-time damage alarming for long-span cable-stayed bridges.

关键词： cable-stayed bridge wavelet packet analysis wavelet packet energy spectrum ambient vibration structural damage alarming

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维普期刊数据库

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Assessment of imaging diagnosis ability of skin tumors in Chinese dermatologists

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Chinese Medical Journal 2019年第17期132卷 2119-2120页

作者： Chang-Bing Shen Xue Shen Cheng-Xu Li Ru-Song Meng Yong Cui Department of Dermatology China-Japan Friendship Hospital Beijing 100029 China Graduate School Peking Union Medical College and Chinese Academy of Medical Sciences Beijing 100730 China Hinda and Arthur Marcus Institute for Aging Research Hebrew SeniorLife and Harvard Medical School Boston MA 02131 USA Department of Dermatology The First Affiliated Hospital Anhui Medical University Hefei 230032 Anhui China Department of Dermatology Specialty Medical Center of the Air Force People’s Liberation Army Beijing 100142 China

Skin tumors begin from normal skin cells, and some parts of them may transform with the potential to reproduce in an out-of-control manner.[1] Skin tumors are exceedingly common and the incidence is increasing at an a... 详细信息

关键词： out-of-control globe alarming

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石油价格波动规律及其预警识别体系研究

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产业经济 2009年第3期

作者：赵惟范海兰

石油价格波动及预警识别理论是研究石油价格在内外因素影响下的变化以及由变化程度映射出的警戒状态及其响应机制的理论。现今主流的石油价格波动理论基本以石油价格量为唯一研究基础，相应的预警识别体系亦与之相附和。就研究效果而言... 详细信息

石油价格波动及预警识别理论是研究石油价格在内外因素影响下的变化以及由变化程度映射出的警戒状态及其响应机制的理论。现今主流的石油价格波动理论基本以石油价格量为唯一研究基础，相应的预警识别体系亦与之相附和。就研究效果而言其直观度较高，但预测准确性较弱，同时预警准值的确定缺乏依据且识别体系简单。本文在沿袭现有油价量为基准的研究方法的同时，创新性地提出以相对率表达价格波动，并以此为基础构建预警识别体系，而警限值亦创造性地运用分位数法确定，并对传统的专家法的合理性作了科学验证以及优化。价格调控依据是波动率，调控基础对象是价格量，价格量的回归使波动平抑后则实现调控目标。

关键词：石油价格波动预警识别 oil price fluctuation alarming identification

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