Research Article

SVEIRS: A New Epidemic Disease Model with Time Delays and Impulsive Effects

Figure 6

The results of numerical simulation on the threshold values , where , .
542154.fig.006a
(a) Time series of , , and . The disease will be permanent
542154.fig.006b
(b) Phase portrait of , of the system  (4)
542154.fig.006c
(c) Phase portrait of , of the system  (4)
542154.fig.006d
(d) Phase portrait of , , and of the system  (4)