Sequence-Based Centrality Measures In Maritime Transportation Networks

Performing centrality analysis on nodes from transportation networks are critical to identify important hubs, understand travel decisions, and assess system performances. Current centrality measures are based on topological characteristics of nodes and edges. When applying those measures to large-scale transportation networks, two problems remain unsolved. First, measures are computed based on simplified travel paths, which only include origins and destinations. Due to the lack of information about waypoints of routes, such network representation may not preserve fine level information about waypoints, routes, and traffic flow patterns, resulting in an inaccurate view of centrality. Second, most centrality measures are global measures that rank all nodes in a network, thus failing to detect nodes of regional importance. Therefore, this paper describes an approach that leverages the concept of sequences to identify key waypoints from frequent travel paths and detect community structures of transportation networks. This approach extends two complementary centrality measures to define the role of nodes within communities. The approach has been tested using tracking data of ships in a regional maritime transportation network. Compared to traditional measurement approaches, the proposed approach can construct compact communities, discover prominent waypoints, and add new insight with local centrality measure.