Policy and Law Assessment of COVID-19 Based on Smooth Transition Autoregressive Model

Figure 13

The fitting result of Brazil. The left axis shows the daily confirmed cases for the real data after smoothness (blue solid line) and its fitted values by the STAR model (blue dashed line). The right axis shows the value of nonlinear functions G changing with time (orange solid line) and the reference line with threshold 0.5 (orange dashed line). The vertical dotted line indicates the sequential released policies: ① close borders with Argentina, Bolivia, Colombia, Guyana, French Guiana, Paraguay, Peru, and Suriname within 15 days, ② ban foreigners by air from China, European Union, Iceland, Norway, Switzerland, the United Kingdom, Australia, Japan, Malaysia, and South Korea, and ③ implement the lockdown policy.