A Note on Alternative Objectives for the Blocks Relocation Problem

摘要

The Blocks Relocation Problem (BRP) is an important problem arising at container terminals when containers have to be transshipped. Recently, we have seen the upcoming discussion whether some objectives are more appropriate than others. While most authors minimize the number of relocations as objective, some minimize the crane's working time. After adapting a given BRP formulation by including the second objective in two variants, a computational study is carried out on benchmark instances from literature applying some sensitivity analysis indicating to which extent optimal solutions change if the objective is replaced. If the number of relocations is minimized, often larger crane working times may be obtained. Conversely, if the crane working time is minimized, often solutions achieving also a minimum number of relocations are found. Based on our analysis, the consideration of alternative objectives like crane working time is recommended.