A Temporal Graphlet Kernel For Classifying Dissemination in Evolving Networks

We introduce the temporal graphlet kernel for classifying dissemination processes in labeled temporal graphs. Such processes can be the spreading of (fake) news, infectious diseases, or computer viruses in dynamic networks. The networks are modeled as labeled temporal graphs, in which the edges exist at specific points in time, and node labels change over time. The classification problem asks to discriminate dissemination processes of different origins or parameters, e.g., diseases with different infection probabilities. Our new kernel represents labeled temporal graphs in the feature space of temporal graphlets, i.e., small subgraphs distinguished by their structure, time-dependent node labels, and chronological order of edges. We introduce variants of our kernel based on classes of graphlets that are efficiently countable. For the case of temporal wedges, we propose a highly efficient approximative kernel with low error in expectation. Our experimental evaluation shows that our kernels are computed faster than state-of-the-art methods and provide higher accuracy in many cases.