Fig. 3.

State transition diagram for the spread of epidemic. Here “S” denotes the state that people are susceptible to the epidemic, “E” denotes the state that people are infected but are not detected, and “I” denotes the state that people are infected and detected. β₁ denotes the infectivity of epidemic. β₂ denotes the infectivity of epidemic on the knowledge-believed nodes. γ denotes the detecting probability of the infected nodes. f denotes the recovery probability of the infected nodes.