A note on: a flexible crane scheduling methodology for container terminals

In Dik and Kozan (2017) published in Flexible Services and Manufacturing Journal, a Tabu search algorithm was proposed for the quay crane scheduling problem raised in the operation of container terminals. According to the computational experiments and results, Dik and Kozan (2017) demonstrated that by relaxing the non-preemption restrictions when handling tasks (i.e., flexible jobs) and quay cranes’ moving pattern to unidirectional/bidirectional manner, through Tabu search, better solutions of the quay crane scheduling problems could be obtained in an efficient way. However, it should be highlighted that compared to most of the relevent researches in the literature, in Dik and Kozan (2017), the initial quay crane positions were disregarded. Dik and Kozan (2017) has discussed that the improvements on makespan can be attributed to flexible jobs and unidirectional/bidirectional schedules. In this note, the impact of initial crane positions on the makespan would be investigated.