Impacts of preference and geography on epidemic spreading

We investigate the standard susceptible-infected-susceptible model on a random network to study the effects of preference and geography on diseases spreading. The network grows by introducing one random node with m links on a Euclidean space at unit time. The probability of a new node i linking to a node j with degree k(j) at distance d(ij) from node i is proportional to k(j)(A)/d(ij)(B), where A and B are positive constants governing preferential attachment and the cost of the node-node distance. In the case of A=0 , we recover the usual epidemic behavior with a critical threshold below which diseases eventually die out. Whereas for B=0 , the critical behavior is absent only in the condition A=1. While both ingredients are proposed simultaneously, the network becomes robust to infection for larger A and smaller B.