The impact of partial capacity reduction on network vulnerability against cascading failure

Recent natural and man-made disasters have revealed the inherent weakness in mutually dependent critical infrastructures. A potential risk in such complex systems is that an influence of failures in one system can propagate along dependency and multiple systems can be broken simultaneously. Hence it is important to understand risks hidden behind dependency. Under the background, we investigate the impact of partial capacity reduction on network vulnerability against cascading failure. This study demonstrates that the partial capacity reduction increases the vulnerability of the whole network and failures can spread out easily. We also show that how critical nodes whose removals bring about devastating damage on the whole network appear in a network. Our results indicate a possibility that nodes which are located not only inside but also outside of the area of the capacity reduction can turn into critical nodes.