Modeling and Analysis of Bifurcation in a Delayed Worm Propagation Model

Figure 8

The phase portrait when 𝜏<𝜏₀ and 𝜏>𝜏₀.

(a) The projection of the phase portrait in (𝑆,𝐼,𝑅)-space when 𝜏<𝜏₀ 

(b) The projection of the phase portrait in (𝑆,𝐼,𝑅)-space when 𝜏>𝜏₀

(c) The phase portrait of susceptible 𝑆(𝑡) and infected 𝐼(𝑡) when 𝜏<𝜏₀

(d) The phase portrait of susceptible 𝑆(𝑡) and infected 𝐼(𝑡) when 𝜏>𝜏₀