允許集貨港與軸心港不直接相連之海運軸輻路網模式

Abstract

貨櫃船舶大型化之規模經濟性促使海運軸輻路網的形成，大船航行於主線軸心港之間，小船則在支線集貨港之間航行。如何選擇最佳的軸心港設置點，將是航商的一個重要課題。本研究以謝尚行、張斐茹（2001）的海運軸輻路網模式為基礎，發展一個允許集貨港與軸心港不直接相連之海運軸輻路網模式，求解航商的最佳軸心港位置與集貨港分派。O’Kelly（1987）的軸輻路網模式與謝尚行、張斐茹（2001）的海運軸輻路網均屬單一指派模式，限制集貨港僅能與軸心港相連。本研究之模式則包含單一指派與支線處理兩部分，首先利用O’Kelly（1987）提出之啟發式解法求得海運軸輻路網之單一指派解，接著對單一指派解進行支線再處理，在允許集貨港與軸心港不直接相連的條件下，導入支線環路之折扣係數，找出最佳的支線連結型態。本研究以範例進行相關參數之敏感度分析，最後以遠東-太平洋-美西之定期貨櫃航線進行實例應用。

The scale economies of large containerships lead to the forming of the marine hub-and-spoke network. In the network, large ships run between hub ports, while small ships are used as feeders between feeder ports. Therefore it is important for shipping companies to choose hub ports in a network. S.H. Hsieh and F.J. Chang (2001) developed a marine hub-and-spoke network model for shipping companies. Due to the single assignment constraint, every feeder port must directly connect to a hub port in that model and the model of O’Kelly (1987). In this paper, a hub-and-spoke network model which permits feeder ports not to connect to hub ports directly is developed basing on the model of S.H. Hsieh and F.J. Chang (2001). The model consists of two parts, single assignment, and rearrangement of branches. To solve the part of single assignment, this paper adopts the heuristic proposed by O’Kelly (1987) instead of the linearation method. Then the rearrangement of branches will be executed based on the single assignment solution, finding the optimal feeder ports allocation pattern without the constraint of connecting hub ports directly. A sensitivity analysis on some critical parameters (i.e., the discount factor) is made for two examples. Finally, a real case application on the Trans-Pacific route is presented.