Recent studies have shown that a system composed from several randomly interdependent networks is extremely vulnerable to random failure. However, real interdependent networks are usually not randomly interdependent, rather a pair of dependent nodes are coupled according to some regularity which we coin inter-similarity. For example, we study a system composed from an interdependent world wide port network and a world wide airport network and show that well connected ports tend to couple with well connected airports. We introduce two quantities for measuring the level of inter-similarity between networks (i) Inter degree-degree correlation (IDDC) (ii) Inter-clustering coefficient (ICC). We then show both by simulation models and by analyzing the port-airport system that as the networks become more inter-similar the system becomes significantly more robust to random failure.
@article{arxiv.1010.4506,
title = {Inter-similarity between coupled networks},
author = {Roni Parshani and Celine Rozenblat and Daniele Ietri and Cesar Ducruet and Shlomo Havlin},
journal= {arXiv preprint arXiv:1010.4506},
year = {2015}
}