英文摘要 |
On this study, we formulated a two-objective model by minimizing bothshipping costs and inventory costs to decide ship size and sailing frequency forcontainer liners. First, shipping and inventory cost functions are formulated fora multi- port calling route. Shipping costs include capital and operating cost,fuel cost, and port charges, while inventory costs include waiting time cost andshipping time cost. Furthermore, we derived a trade-off equation betweenshipping costs and inventory costs that shows all solutions of ship size andsailing frequency, and identified that it is a hyperbola function, which could beshown in objective value space. Accordingly, Pareto optimal solutions of thetwo-objective model are then determined, and ship size and sailing frequencydecision analysis can be made. The optimum ship size for each level ofinventory cost is shown and the effects of inventory costs, economies of ship size,and service speed on decision are also illustrated. Besides, we derived therelationship between the optimum ship size and container flow, and showed thatthe optimum ship size tended to be the ship with the minimum shipping cost ascontainer flow increases. Finally, a case study regarding TranspacificNorthwest Service justified the theoretical findings. |