Dengue is one of the most prominent tropical epidemic diseases present in the Rio de Janeiro city and Southeast part of Brazil, due to the widespread conditions of occurrence of the dengue vector, the mosquito Aedesae...Dengue is one of the most prominent tropical epidemic diseases present in the Rio de Janeiro city and Southeast part of Brazil, due to the widespread conditions of occurrence of the dengue vector, the mosquito Aedesaegypti, such as high-temperature days interlaced with afternoon or nocturnal rainstorms in summer. This work has the objective of investigating the relationships between variabilities of the El Ni?o-South Oscillation (ENSO) and greater epidemics of dengue in Rio de Janeiro city. To accomplish this goal, the analysis and signal decomposition by cross-wavelet transform (WT) was applied to obtain the cross variability associated with variations of power and phase of both signals by characteristic periods and along with the time series. Data considered in the analysis are (the decimal logarithm of normalized value) of the monthly available notifications of dengue worsening, provided by the public health system of Brazil, and the Southern Oscillation Index (SOI) Ni?o 3.4 data, provided by the National Oceanic and Atmospheric Administration (NOAA), in the period 2000-2017. A maximum cross-wavelet power close to 0.45 was obtained for the representative period of 1 year and also to periods between 3 and 4 years, associated with the positive phase of the SOI index (i.e. , La Ni?a) or with a transition to the positive phase. The evolution of the combined variability of SOI and dengue can be expressed by progressive differences in phase along the time, eventually resulting in yielding phases (i.e., La Niña-Dengue epidemic).展开更多
针对跨海大桥桥墩腐蚀损伤识别问题,通过振动台试验与有限元模拟,验证小波总能量变化(wavelet total energy change, WTEC)指标的适用性.试验采用钢筋截面缩减法模拟局部腐蚀,采集地震波作用下动态响应数据,分析WTEC指标在桥墩损伤识别...针对跨海大桥桥墩腐蚀损伤识别问题,通过振动台试验与有限元模拟,验证小波总能量变化(wavelet total energy change, WTEC)指标的适用性.试验采用钢筋截面缩减法模拟局部腐蚀,采集地震波作用下动态响应数据,分析WTEC指标在桥墩损伤识别中的有效性.结合有限元模型,系统分析采样频率、噪声水平和地震强度对损伤识别精度的影响规律.研究结果表明:在高采样频率低噪声条件下,WTEC具有更高识别精度,证实该方法可为跨海大桥腐蚀损伤的早期诊断提供技术支撑,对提升极端环境下桥梁结构安全性和服役寿命具有工程应用价值.展开更多
文摘Dengue is one of the most prominent tropical epidemic diseases present in the Rio de Janeiro city and Southeast part of Brazil, due to the widespread conditions of occurrence of the dengue vector, the mosquito Aedesaegypti, such as high-temperature days interlaced with afternoon or nocturnal rainstorms in summer. This work has the objective of investigating the relationships between variabilities of the El Ni?o-South Oscillation (ENSO) and greater epidemics of dengue in Rio de Janeiro city. To accomplish this goal, the analysis and signal decomposition by cross-wavelet transform (WT) was applied to obtain the cross variability associated with variations of power and phase of both signals by characteristic periods and along with the time series. Data considered in the analysis are (the decimal logarithm of normalized value) of the monthly available notifications of dengue worsening, provided by the public health system of Brazil, and the Southern Oscillation Index (SOI) Ni?o 3.4 data, provided by the National Oceanic and Atmospheric Administration (NOAA), in the period 2000-2017. A maximum cross-wavelet power close to 0.45 was obtained for the representative period of 1 year and also to periods between 3 and 4 years, associated with the positive phase of the SOI index (i.e. , La Ni?a) or with a transition to the positive phase. The evolution of the combined variability of SOI and dengue can be expressed by progressive differences in phase along the time, eventually resulting in yielding phases (i.e., La Niña-Dengue epidemic).
文摘针对跨海大桥桥墩腐蚀损伤识别问题,通过振动台试验与有限元模拟,验证小波总能量变化(wavelet total energy change, WTEC)指标的适用性.试验采用钢筋截面缩减法模拟局部腐蚀,采集地震波作用下动态响应数据,分析WTEC指标在桥墩损伤识别中的有效性.结合有限元模型,系统分析采样频率、噪声水平和地震强度对损伤识别精度的影响规律.研究结果表明:在高采样频率低噪声条件下,WTEC具有更高识别精度,证实该方法可为跨海大桥腐蚀损伤的早期诊断提供技术支撑,对提升极端环境下桥梁结构安全性和服役寿命具有工程应用价值.
