Date and Time: Wednesday, 8 May – 11:00-12.00
Location: EPSRC Centres for Doctoral Training Suite, South Kensington Campus, the ICSM Building, Level 4N, Room 402
Speaker: Professor Sofia Olhede
Title: Modeling Network Populations via Graph Distances
Abstract: Networks are a key tool to characterise dependence between nodes or actors. Modern observations often take the form of many networks. In this talk, the core idea is to parametrize a distribution on labelled graphs in terms of a Frechét mean graph (which depends on a user-specified choice of metric or graph distance) and a parameter that controls the concentration of this distribution about its mean. Entropy is the natural parameter for such control, varying from a point mass concentrated on the Frechét mean itself to a uniform distribution over all graphs on a given vertex set. We provide a hierarchical Bayesian approach for exploiting this construction, along with straightforward strategies for sampling from the resultant posterior distribution. We conclude by demonstrating the efficacy of our approach via simulation studies and a multiple-network data analysis example drawn from systems biology.
This is joint work with Simon Lunagomez and Patrick Wolfe