以利潤最大化為目標之貨櫃船隊定線模式

Abstract

近年來，因貨櫃船大型化的趨勢，海運定期貨櫃船運逐漸發展成軸輻路網的營運模式。即是：運用大型貨櫃船航行於軸心港（hub ports）之間，小型貨櫃船航則行於集貨港（feeder ports）與軸心港之間，進行集貨的工作。 航商在運用軸輻路網的方式營運時，最基本考量的因素為：母船多靠幾個軸心港，營運成本會增加，但運費收入（每航次之載櫃率）也能增加，關鍵就在於利潤（運費收入－營運成本）能否增加。在面對此問題時，以成本最小化為目標的軸心港位置選擇模式，所能提供的資訊就略有不足。因此，本研究建立一個以利潤最大化為目標之『貨櫃船隊定線模式（a model for routing containerships）』，利用模式分析求解航商應選擇停靠哪些軸心港，才能有最大的利潤。 本研究建立之模式分為兩部份，先決定軸輻路網上主線母船停靠的軸心港（Model 1），其餘港口（集貨港）再指派連接至最接近的軸心港，利用子船於各支線上完成集貨的工作（Model 2），兩個部份的目標值總和，即為本模式利潤最大化之目標值。模式求解方面，以O’Kelly(1987)提出的HEUR 1的解法概念求解Model 1；而Model 2部份，則允許集貨港與軸心港不直接相連，並以迴圈航線為支線上子船的航行方式，配合主線母船轉運的櫃量，來決定各支線上子船船隊數目。本研究最後以越太平洋航線（遠東∼北美西岸）為例，進行實例分析。

In recent years, transoceanic containerships are built larger and larger so as to lead to the formation of marine hub-and-spoke network. In the networks, large ships run between hub ports, while small ships are used as feeders between feeder ports. In the networks, the factor for the liner to operate depends on the ability to produce the profit. A containership berths more ports will not only increase the operation costs, but also generate the revenue. The critical point is the effect of trade off (revenue - cost) will benefit for the containership routing. However, the previous models were unable to provide the liner with the selection of the hubs in order to seed maximum profit. The main purpose of this paper is, therefore, to propose a hub-and-spoke model of routing containerships to solve the problem. The model consists of two parts. One, Model 1 decides the location of hub ports. The other, Model 2 assigns adequate feeders on the branch network. The total sum of two objective values in models is the maximum profit. The concept of HEUR 1 which O’Kelly proposed in 1987 is used to solve the function of Model 1. Model 2 decides the number of feeders on branch network, given the loop type routing to match with the traffic flow. This paper ends with an application of the real Trans-Pacific routing and the sensitivity analysis.