Figure 9.

Forecasting and optimal control results for Indonesian data from 2021 to 2070 when medical mask intervention improved, but case detection left as a constant at ${\displaystyle u_1=0.151}$ . Panels (a) to (e) represent the dynamic of ${\displaystyle S,E,I_1,I_2}$ and ${\displaystyle R}$ , respectively. Panel (f) represent the case incidence per 100 000 people while panels (g) and (h) show the dynamic of control ${\displaystyle u_1}$ and ${\displaystyle u_2}$ , respectively.