Schedule design and container routing in liner shipping
A liner shipping company seeks to provide liner services with shorter transit time compared with the benchmark of market-level transit time because of the ever-increasing competition. When the itineraries of its liner service routes are determined, the liner shipping company designs the schedules of the liner routes such that the wait time at transshipment ports is minimized. As a result of transshipment, multiple paths are available for delivering containers from the origin port to the destination port. Therefore, the medium-term (3 to 6 months) schedule design problem and the operational-level container-routing problem must be investigated simultaneously. The schedule design and container-routing problems were formulated by minimization of the sum of the total transshipment cost and penalty cost associated with longer transit time than the market-level transit time, minus the bonus for shorter transit time. The formulation is nonlinear, noncontinuous, and nonconvex. A genetic local search approach was developed to find good solutions to the problem. The proposed solution method was applied to optimize the Asia-Europe-Oceania liner shipping services of a global liner company.