Use of FFTBM by signal mirroring for sensitivity study

Application of FFTBM with signal mirroring to improve accuracy assessment of MELCOR code

“…In implementation of original FFTBM, it is revealed that there is an unphysical edge effect on FFTBM results when experimental signals sharply increase or decrease (Prošek et al, 2008). Fluctuations in the accuracy index (AA) of original FFTBM caused by the difference (edge) between the first and last data points of the investigated signals (Prošek and Leskovar, 2015). Discrete Fourier transform used in the FFTBM, considers the time-dependent signal as an infinite periodic signal (Fig.…”

“…Signal mirroring enables to have symmetrized signals with the identical characteristics without introducing the edge, when treated as an infinite periodic signal (Fig. 1) (Prošek and Leskovar, 2015). Thus, FFTBM-SM can eliminate the fluctuations in accuracy assessment of TH codes, especially when performing assessments for a large number of time-intervals.…”

“…triangular shape) (Prošek et al, 2008). Difference between the first and last data points of the investigated signals leads to presence of an artificial edge in periodically extended signals when performing the discreet Fourier transform (Prošek and Leskovar, 2015). Accuracy assessment is thus affected by frequencies from such artificial edge.…”

Prediction of dynamic responses of floating structures using NARX with mirroring technique

“…Many study cases ware modelled using signal mirroring with some advantages; eliminate restriction of time-intervals phenomenon and increase accuracy by eliminating of fluctuations when signal is sharply increase or decrease, and faster convergence rates [47][48][49][50][51][52][53][54]. Ha [47] use signal mirroring on Fourier Transform-based to quantify the experimental and calculation result show a significant improvement of the accuracy.…”

“…Ha [47] use signal mirroring on Fourier Transform-based to quantify the experimental and calculation result show a significant improvement of the accuracy. Andrej [48] shows that Fast Fourier Transform by signal mirroring can contribute to the increase of the efficiently of the study when parameter is varied at a time. In this study, NARX model for floating structures has been performed with mirroring technique.…”