Synchronization in Directed Complex Networks Using Graph Comparison Tools

This paper proposes lower bounds for the coupling strengths of oscillators in directed networks to guarantee global synchronization. The novel idea of graph comparison from spectral graph theory is employed so that the combinatorial features of a given network can be fully utilized to simplify computations. For large networks that can be decomposed into a set of smaller strongly connected components, the comparison can be carried out at the local level as well. To validate theoretical analysis, examples are provided to demonstrate how to apply the proposed methodologies to typical directed complex networks.