A stochastic block model consists of a random partition of n vertices into
blocks 1,2,...,K for which, conditioned on the partition, every pair of
vertices has probability of adjacency entirely determined by the block
membership of the two vertices.
It is becoming increasingly popular to represent myriad and diverse data sets
as graphs. When the labels of vertices of these graphs are unavailable, graph
matching (GM)---the process of determining which permutation assigns vertices
of one graph to those of another---is a computationally daunting problem. This
work presents an inexact strategy for GM. Specifically, we frame GM as a
quadratic assignment problem, and then relax the feasible region to its convex
hull.
This manuscript considers the following "graph classification" question:
given a collection of graphs and associated classes, how can one predict the
class of a newly observed graph? To address this question we propose a
statistical model for graph/class pairs. This model naturally leads to a set of
estimators to identify the class-conditional signal, or "signal subgraph,"
defined as the collection of edges that are probabilistically different between
the classes.
Deducing the structure of neural circuits is one of the central problems of
modern neuroscience. Recently-introduced calcium fluorescent imaging methods
permit experimentalists to observe network activity in large populations of
neurons, but these techniques provide only indirect observations of neural
spike trains, with limited time resolution and signal quality. In this work we
present a Bayesian approach for inferring neural circuitry given this type of
imaging data.