Locating the Diffusion Source in Networks by Critical Observers

This paper tackles the problem of locating the diffusion source in networks. Designating all nodes of the network as observers for locating the diffusion source is very complex and impracticable. To make this problem solvable in a simple manner, only a subset of nodes is used as observers. Choosing these observers can be a challenging task, as the effectiveness of the observers depends on various factors including the network topology, the diffusion process, and the available resources for observing the diffusion source. Several techniques have been proposed for selecting observers citing betweenness centrality, closeness centrality, high degree nodes, and randomization. This paper advances the state of the art by proposing the first solution, to our knowledge, for locating the diffusion source problem where the observers are selected as critical nodes.