Figure 4.

RMSE graphs (a) when ${\mathrm{s}}_{\mathrm{n}}=0.8$ and ${\mathrm{s}}_{\sigma }$ was changed, and (b) when ${\mathrm{s}}_{\sigma }=0.4$ and ${\mathrm{s}}_{\mathrm{n}}$ was changed. Error bars in each graph are standard deviations of the RMSE.