Eelco van Asperen

Advanced methods for container stacking

In this paper, we study stacking policies for containers at an automated container terminal. It is motivated by the increasing pressure on terminal performance put forward by the increase in the size of container ships. We consider several variants of category stacking, where containers can be exchanged during the loading process. The categories facilitate both stacking and online optimization of stowage. We also consider workload variations for the stacking cranes.

Online rules for container stacking

Container stacking rules are an important factor in container terminal efficiency. In this paper, we investigate two concepts to increase efficiency and compare them to several benchmark algorithms, using a discrete-event simulation tool. The first concept is to use knowledge about container departure times, in order to limit the number of reshuffles. We stack containers leaving shortly before each other on top of each other. The second concept is the trade-off between stacking further away in the terminal versus stacking close to the exit points and accepting more reshuffles. It is concluded that even the use of imperfect or imprecise departure time information leads to significant improvements in efficiency. Minimizing the difference in departure times proved to be important. It was also found that the trade-off between stacking further away in the terminal versus stacking close by the exit points and accepting more reshuffles leads to improvements over the benchmark.

Floating stocks in FMCG supply chains: using intermodal transport to facilitate advance deployment

Purpose – The purpose of this paper is to consider the use of temporary storage offered by intermodal transshipment points to position some stock of fast moving consumer goods in advance of demand; this floating stock concept combines transport and inventory management. Intermodal transport is compared with direct road transport for a supply chain.Design/methodology/approach – First an analytical comparison is made which shows that the floating stock concept has advantages in inventories over pure road and intermodal transport. Next, a simulation study of a real case is made which quantifies the cost‐differences in detail.Findings – It is found that both storage costs can be lowered and shorter response times be gotten by sending shipments in advance to intermodal terminals. The advance positioning can offset the disadvantage of a longer transit time in intermodal transport.Research limitations/implications – Demand needs to be somewhat predictable. The pooling effects depend on geographical layout of the...

Evaluating container stacking rules using simulation

Container stacking rules are an important factor in container terminal efficiency. In this paper, we describe a discrete-event simulation model that has been used to evaluate online container stacking rules. We build on prior research and demonstrate that results obtained for smaller stacking areas are also valid for a larger stacking area. The use of information regarding container departure times (even if is imperfect) is shown to be more beneficial than the use of exchange categories. Stacking rules that take the workload of the automated stacking cranes into account outperform rules that do not. The experiments conducted with the simulation model show that it can capture the amount of detail required and that it is flexible enough to support the evaluation of the stacking rules.