Fig. 5
Two examples of the model (4) fitting to the empirical S 1(τ): a–c Subject sK, 16 years old, (high cyclicity), ω 1 = 0.239 (f 1 = 9.51 Hz), θ 1 = 0.6, ω 2 = 0.232 (f 2 = 9.23 Hz), θ 2 = 0.95, ω 3 = 0.245 (f 3 = 9.75 Hz), θ 3 = 0.05, α 0 = 0.17, β 0 = 0.054, w 1 = 0.7, w 2 = 0.2, w 3 = 0.1; mean relative error fitting is 1.4 %; d Subject sR, 12 years old, (low cyclicity), ω 1 = 0.239 (f 1 = 9.51 Hz), θ 1 = −0.05, ω 2 = 0.157 (f 2 = 6.25 Hz), θ 2 = −0.05, ω 3 = 0.129 (f 3 = 5.13 Hz), θ 3 = 0.15, α 0 = 0.17, β 0 = 0.001, w 1 = 0.6, w 2 = 0.2, w 3 = 0.2, mean error fitting is 2 %; Error fitting = 100 % \(|{S_{1}} (\tau)- {S_{1}^{*}}(\tau)|/{S_{1}} (\tau)\), mean relative error fitting is calculated over the time lag τ range of 1 s (τ \(\in\) [0, 250]); [S 1 *(0)]′ are everywhere ≥ 0