This study investigates the scheduling problem of the tandem quay crane (TQC), which is a new type of loading/unloading device used at container terminals. The TQC can execute either a single-lift or tandem-lift at a time. Considering the changeover time between the above two operational modes of the TQC and the weight limitation for executing a tandem-lift, a novel integer linear programming model is established to minimize the time needed for unloading the containers from the containership, and valid inequalities are introduced to enhance the model. Then, an exact algorithm based on logic-based Benders decomposition is applied to solve the problem. The proposed approach decomposes the problem into a mode-assignment master problem and an operation-sequencing slave problem. Logic-based cuts are proposed to ensure the convergence of the algorithm, and several enhancement measures are developed to accelerate the convergence speed. The computational results indicate that the model is superior to the previous model proposed in the literature, and the proposed inequalities are effective. Moreover, the exact algorithm was verified to be efficient for solving realistically sized instances within an acceptable time.

本研究调查了双人码头起重机 (TQC) 的调度问题，TQC 是一种用于集装箱码头的新型装卸设备。TQC 可以一次执行单次提升或串联提升。考虑到 TQC 上述两种操作模式之间的转换时间和执行串联吊运的重量限制，建立了一种新颖的整数线性规划模型，以最小化从集装箱船上卸下集装箱所需的时间，并引入了有效的不等式来增强模型。然后，应用基于逻辑的Benders分解的精确算法来求解该问题。所提出的方法将问题分解为模式分配主机问题和操作排序从机问题。提出了基于逻辑的切割以确保算法的收敛性，并制定了多项增强措施以加快收敛速度​​。计算结果表明该模型优于以往文献中提出的模型，所提出的不等式是有效的。此外，该精确算法已被验证可有效地在可接受的时间内解决实际大小的实例。