Fig. 2: A conceptual model of a shipping network.
From: An approach to assessing tsunami risk to the global port network under rising sea levels
Changes in network (a) before a disruption, and (b) after a disruption to illustrate the concepts of degree and betweenness centralities. Nodes (seaports) are represented by yellow circles and the blue lines connecting between two nodes represent edges (service routes between two ports). In (a), Hong Kong represents a port with the highest degree of centrality as it connects to the greatest number of nodes, and it also possesses a high betweenness centrality as it lies in the shortest paths to most other nodes. In (b), an event resulted in the loss of the functions at Hong Kong port. Shanghai and Tokyo serve as alternative ports to travel between Pusan and Perth, and hence, the ratio of change in betweenness centrality is greater than 0. As the service is rerouted, Sydney no longer serves as a port between Pusan and Perth, resulting in a less than 0 ratio.
