Towards designing robust coupled networks

TL;DR

This paper introduces a betweenness-based method for selecting autonomous nodes in coupled networks to prevent abrupt failures, significantly reducing the number of nodes needed for robustness and revealing universal scaling behavior.

Contribution

The study presents a systematic, betweenness-based strategy for autonomous node selection that enhances network robustness with fewer nodes and uncovers universal tricritical scaling laws.

Findings

Autonomous nodes can be optimally selected using betweenness centrality.

The proposed method reduces autonomous nodes needed by a factor of five compared to random selection.

The transition to collapse exhibits tricritical scaling with universal exponents.

Abstract

Natural and technological interdependent systems have been shown to be highly vulnerable due to cascading failures and an abrupt collapse of global connectivity under initial failure. Mitigating the risk by partial disconnection endangers their functionality. Here we propose a systematic strategy of selecting a minimum number of autonomous nodes that guarantee a smooth transition in robustness. Our method which is based on betweenness is tested on various examples including the famous 2003 electrical blackout of Italy. We show that, with this strategy, the necessary number of autonomous nodes can be reduced by a factor of five compared to a random choice. We also find that the transition to abrupt collapse follows tricritical scaling characterized by a set of exponents which is independent on the protection strategy.