Active querying approach to epidemic source detection on contact networks

In this section, we describe the three main components of our approach. First, we introduce the inference mechanism. Second, we describe the method we use to compute individual node state probabilities given a source node and a starting time. Finally, we present three active querying strategies.

Inference

We assume that only the SIR parameters of the propagation process are known. Hence, our problem consists of inferring both the source node Q and the duration until the first observation T, given the evidence \(E_{t_1}\). Note that once we infer T, we can also infer the starting time with