Breakdown of interdependent directed networks

Abstract

Significance: Real-world complex systems interact with one another, and these interactions increase the probability of catastrophic failure. Using interdependent networks to model these phenomena helps understand a system’s robustness and enables design of more robust infrastructures. Previous research has been limited to an idealized case where each layer is undirected, but almost all real-world networks are directed and exhibit in-degree and out-degree correlations. Therefore, we develop a general theoretical framework for analyzing the breakdown of interdependent directed networks with, or without, in-degree and out-degree correlations, and apply it to real-world international trade networks. Surprisingly, we find that the robustness of interdependent heterogeneous networks increases, whereas that of interdependent homogeneous networks with strong coupling strengths decreases with in-degree and out-degree correlations.