| T = t0; CN = cn0 |
| Function PSI_calc(T, CN) |
| m0 = M(CN) |
| si0 = SI(CN) |
| psi0 = m0/si0 |
| RETURN psi0 |
| Function AIR_calc(T, CN) |
| Len1 = 30; Len2 = 5 |
| If COVID_Vaccine(T) ==0 |
| train = COVID_Accumulation(T,T + Len1) |
| test = COVID_Accumulation(T + Len1, T + Len1 + Len2) |
| else |
| train = COVID_Accumulation(T,T + Len1)-COVID_Vaccine(T,T + Len1) |
| test = COVID_Accumulation(T + Len1,T + Len1 + Len2)- |
| COVID_Vaccine(T + Len1, T + Len1 + Len2) |
| Model = ARIMA(px, dx, qx, train) |
| Forecast = Model(test) |
| If Forecast(1) > k ==TRUE then |
| coef = k-Forecast_data(1) |
| Else |
| coef = k-Forecast_data(1) |
| Forecast = Forecast(2:Forecast_length) + coef |
| Diff(j) = MSE(Forecast, test) |
| AIR = Forecast(T,T + Len1 + Len2)/COVID_Accumulation(T, T + Len1 + Len2) |
| RETURN AIR |
| Function Turning_Point_Calc(T, CN, AIR, PSI) |
| CI =0.9 |
| psi_UK = PSI_calc(T_UK, UK) #Same for Belgium, France and Germany |
| psi_TL = (MAX(psi_UK,...psi_Belgium)-MIN(psi_UK,...psi_Belgium))/2 |
| Turning_Point = T; k =1 |
| While k < =10 |
| If (AIR(T + k)/PSI) - AVG(psi_UK, ... psi_Belgium) < =psi_TL |
| Print (“Turning Point Found on kth date!”); |
| Turning_Point = Turning_Point + k; |
| Break; |
| Else |
| k = k +1; |
| For k =1 : 10 |
| AIR_upper[T + k] = AIR[T + k] + Delta |
| AIR_lower[T + k] = AIR[T + k] -Delta |
| Return Turning Point, AIR_upper, AIR, AIR_lower |
