Recovery of coupled networks after cascading failures

With society's increasing dependence on critical infrastructure such as power grids and communications systems, the robustness of these systems has attracted significant attention. Failure of some nodes can trigger a cascading failure, which completely fragments the network, necessitating recovery efforts to improve robustness of complex systems. Inspired by real-world scenarios, this paper proposes repair models after two kinds of network failures, namely complete and incomplete collapse. In both models, three kinds of repair strategies are possible, including random selection (RS), node selection based on single network node degree (SD), and node selection based on double network node degree (DD). We find that the node correlation in each of the two coupled networks affects repair efficiency. Numerical simulation and analysis results suggest that the repair node ratio and repair strategies may have a significant impact on the economics of the repair process. The results of this study thus provide insight into ways to improve the robustness of coupled networks after cascading failures.