Assessing and safeguarding network resilience to nodal attacks

This article introduces new methods for evaluating and improving resilience of network connectivity to attacks on nodes of the network. Network connectivity is evaluated using a centrality measure that quantifies sensitivity of the size of the largest connected component to node removals. Based on this centrality measure, a new method for improving resilience is introduced, called edge rewiring. The topology of the power grid of western U.S. states is used to illustrate the proposed method. Using the proposed centrality measure, we show that the power grid topology is especially vulnerable to nodal attacks. In particular, using the proposed centrality measure, an attacker could reduce the largest component size by nearly a factor of two by only targeting 0.2 percent of the nodes. More importantly, we show that network resilience can be greatly improved via a few edge rewires without introducing additional edges in the network.