• Title/Summary/Keyword: cross stochastic Fourier spectrum

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Fluctuating wind field analysis based on random Fourier spectrum for wind induced response of high-rise structures

  • Lin, Li;Ang, A.H.S.;Xia, Dan-dan;Hu, Hai-tao;Wang, Huai-feng;He, Fu-qiang
    • Structural Engineering and Mechanics
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    • v.63 no.6
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    • pp.837-846
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    • 2017
  • An accurate calculation of the stochastic wind field is the foundation for analyzing wind-induced structure response and reliability. In this research, the spatial correlation of structural wind field was considered based on the time domain method. A method for calculating the stochastic wind field based on cross stochastic Fourier spectrum was proposed. A flowchart of the proposed methodology is also presented in this study to represent the algorithm and workflow. Along with the analysis of regional wind speed distribution, the wind speed time history sample was calculated, and the efficiency can therefore be verified. Results show that the proposed method and programs could provide an efficient simulation for the wind-induced structure response analysis, and help determine the related parameters easily.

Improved Correlation Identification of Subsurface Using All Phase FFT Algorithm

  • Zhang, Qiaodan;Hao, Kaixue;Li, Mei
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.14 no.2
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    • pp.495-513
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    • 2020
  • The correlation identification of the subsurface is a novel electrical prospecting method which could suppress stochastic noise. This method is increasingly being utilized by geophysicists. It achieves the frequency response of the underground media through division of the cross spectrum of the input & output signal and the auto spectrum of the input signal. This is subject to the spectral leakage when the cross spectrum and the auto spectrum are computed from cross correlation and autocorrelation function by Discrete Fourier Transformation (DFT, "To obtain an accurate frequency response of the earth system, we propose an improved correlation identification method which uses all phase Fast Fourier Transform (APFFT) to acquire the cross spectrum and the auto spectrum. Simulation and engineering application results show that compared to existing correlation identification algorithm the new approach demonstrates more precise frequency response, especially the phase response of the system under identification.