A three-level hierarchical workload management scheme for yard cranes in container terminals

Abstract

We propose a three-level, hierarchical scheme for yard crane (YC) workload management in container terminals. Level 1 distributes YCs among different rows in the storage yard at suitable times based on predicted future workload. This is done a few times during a shift of 8 hours. Level 2 dispatches YCs to work in various non-overlapping working zones in each row for the time window in between two rounds of YC re-distributions at Level 1. Level 3 determines the serving sequences of vehicle jobs for an YC in a working zone over a period of time (e.g., a sub-planning window). The algorithms for levels 2 and 3 have been published elsewhere. This paper proposes the proportional distribution and the uniform distribution strategies for YC deployment at level 1. We compare the performance of the three-level hierarchical scheme in terms of average job waiting times and the average number of overflow jobs at the end of each planning window under the two distribution strategies. © 2011 Springer-Verlag.