Figure 3.

The indices of the “real” relaxation modulus (36) approximation by the FMM: (a) the mean-square empirical index $Q_N\left({\mathit{g}}_N^{\ast }\right)$, Equation (24), (b) the integral quadratic sampling instants-independent index $Q\left({\mathit{g}}_N^{\ast }\right)$, Equation (26), as the functions of the number of measurements $N$ and noises $\sigma =2,5,8 \left[\mathrm{P}\mathrm{a}\right]$; the horizontal purple lines correspond to the optimal integral index $Q\left({\mathit{g}}^{\ast }\right)$ defined in Equation (27).