SI process

This article is one in a series by the authors on epidemic outbreak modeling and presents a practical implementation and validation of a two-scale (micro–macro) scheme for simulating epidemic spread on networks with explicit community structure. At the micro level, each community is modeled by a stochastic SI process with a fixed transmission coefficient on a complete internal graph; at the macro level, communities are connected by rare import events whose intensities depend on the donor’s current ‘infectiousness,’ the recipient’s ‘susceptibility,’ and the weights of inter-community links.