Fig. 8. Perturbation analysis of unknown parameters in case 5.

Using the finite element solver, we calculate the root mean squared error of the displacement data on the measurement points caused by the perturbation $(\mathrm{\Delta }R*,\mathrm{\Delta }{\mathrm{\mu }}_{\mathrm{i}}^{*})$ on the reference values of the shear modulus $({\mathrm{\mu }}_{\mathrm{i}}^{*})$ and the radius of the inclusion (R*). (A) Absolute error of displacement data for various perturbations on $(R*,{\mathrm{\mu }}_{\mathrm{i}}^{*})$. The red star at the center corresponds to the unperturbed state $(\mathrm{\Delta }R*\mathit{=}\mathrm{\Delta }{\mathrm{\mu }}_{\mathrm{i}}^{*}=0)$. (B) Absolute error of measurements along the diagonal lines of the $(R*,{\mathrm{\mu }}_{\mathrm{i}}^{*})$ domain in (A). Perturbation states on line 1 satisfy $\mathrm{\Delta }R*\mathrm{\Delta }{\mathrm{\mu }}_{\mathrm{i}}^{*}>0$. Perturbation states on line 1 satisfy $\mathrm{\Delta }R*\mathrm{\Delta }{\mathrm{\mu }}_{\mathrm{i}}^{*}<0$.