Interdependent Response of Networked Systems

Continuous functionality of critical infrastructure systems is essential to support the social and economic organization of productive sectors within a country. Electric power, potable water, natural gas, telecommunications, and transportation are examples of these critical systems, whose nature makes them suitable for network analysis. This study presents the topological characterization of two interdependent small-sized real networks. The same properties are calculated for ideal models of comparable size to the real networks. Selected topological properties are monitored for these interdependent systems when subjected to external or internal disruptions (e.g., deliberate attacks, malfunction due to aging, or lack of maintenance). This study introduces a simple rule to establish interdependencies among network elements based upon geographical proximity. The effect of the degree of coupling between networks is investigated with a tunable parameter that drives the networks from independence to complete interdependence. Network detrimental responses are observed to be larger when interdependencies are considered after disturbances. Effective mitigation actions could take advantage of the same network interconnectedness that facilitates cascading failures.