Exact Algorithms for Robust Quay Crane Scheduling Problems

The processing time of loading and unloading tasks is usually fluctuating due to uncertain factors at container terminals. However, most research treats it as deterministic. This paper proposes a two-stage robust optimization approach to tackle the uncertainty proactively. Two kinds of cuts are proposed to tighten the searching space. Some techniques are applied to linearize the subproblem. Both Benders decomposition and column-and-constraint generation algorithms are adopted to solve the robust model, with the two algorithms compared analytically and numerically. Based on extensive experiments, we validate the effectiveness of the algorithms and find the situations that are suitable to the robust model.