The study of the unidirectional quay crane scheduling problem: complexity and risk-aversion

As a special case of the quay crane scheduling problem, the unidirectional quay crane scheduling problem has been received more and more attention. In this paper, we analyze the computational complexity of the unidirectional quay crane scheduling problem and propose a tighter mixed integer programming formulation. Next, we develop three makespan-constrained models to obtain risk-averse solutions to mitigate the impacts of ship instability and solution infeasibility (thus, need to revamp or even reschedule the plans). Comprehensive numerical experiments are designed to investigate the benefits of the tighter formulation and the three optimization models for risk-aversion.