Table 1 The average frequencies and periods of each decomposed IMF by WAFA and their periodic meanings.
From: Nonlinear frequency analysis of COVID-19 spread in Tokyo using empirical mode decomposition
IMF | Averaged frequency \(\pm \; \mathrm{SD}\) (cycles per day) | Averaged period \(\pm \; \mathrm{SD}\) (days) | The meaning of periodic activities |
|---|---|---|---|
1 | 0.221 \(\pm \;{0.064}\) | 4.519 \(\pm \;{1.312}\) | Various random factors |
2 | 0.128 \(\pm \;{0.021}\) | 7.797 \(\pm \;{1.267}\) | Variations in daily PCR and antigen inspections on a weekly cycle |
3 | 0.053 \(\pm \;{0.017}\) | 18.988 \(\pm \;{6.112}\) | External influences restricting COVID-19 spread |
4 | 0.017 \(\pm \;{0.006}\) | 57.171 \(\pm \;{19.261}\) | COVID-19 outbreak and retreat in Tokyo |
