Assessing and improving the structural robustness of global liner shipping system: A motif-based network science approach

Liner shipping carries about 70% of the total value of world's seaborne trade, and thus the robust functioning of global liner shipping network (GLSN) is essential for building robust global maritime logistics systems. However, understanding and improving the underlying structural robustness of GLSN is an important challenging topic. This paper contributes to this topic by proposing a motif-based network science approach to address two crucial tasks therein. First, based on the extensive mining of four-node motifs in the GLSN, we propose a novel node centrality metric named motif centrality to characterize the importance of a port in the GLSN, which proves its effectiveness in identifying critical ports for maintaining the GLSN structural robustness. Second, after assessing the GLSN structural robustness against some worst-case scenarios of port disruptions, we propose two motif-based link-adding strategies to improve the GLSN structural robustness. Experimental results prove their effectiveness as compared with random link-adding strategies. For further scrutinization, one strategy is extended to the individual country level and is found useful in improving the structural robustness of liner shipping connections of most countries, especially many underdeveloped maritime countries. Some practical and theoretical implications are finally discussed.