需求擾動對軸輻航空貨運網路設計影響之研究

Abstract

航空網路設計攸關航空公司的營運績效及競爭力，而軸輻航空貨運網路系統因能發揮規模經濟效果，廣為航空公司所採用，其中轉運中心因可帶動航空及相關產業的發展，向來為全球各主要機場追求的目標。然現實世界存在季節性、區域消長等各種需求擾動因素，而這些市場的波動均會對航空網路設計，甚至轉運中心的選擇等長期策略產生影響，航空公司對相關衝擊應預為評估及因應。 鑑於以往大部分軸輻航空網路研究所採用的數學規劃模式不易反映該系統具有規模經濟的特性，本研究採解析性方法，藉由構建物流成本函數，以成本最小化為目標進行軸輻航空貨運網路設計。本研究建立之模式可反映貨物時間價值、機型、貨運量、起迄點與轉運中心的相對位置對物流成本的影響，更可觀察規模經濟在軸輻航空網路中所發揮的關鍵效果。另本研究模式可就需求擾動對航空網路設計的機型、班次及運送路線的影響事先進行可靠度評估，研究結果顯示各航線因運量、航程，以及可供選擇之機型，在機型、班次的可靠度上會有很大的差異。另軸輻航空貨運網路因將貨物合併於主要航線上運送，其貨運量波動可能更為劇烈，最適機型、班次需調整之機會也隨之增加。 本研究亦透過三種不同情境的模擬，探討亞太地區因區域經濟消長對航空網路設計，甚至對轉運中心選擇產生之影響，研究結果發現一機場欲發展成為轉運中心，其地理位置比其當地運量扮演更關鍵的角色。原本香港具有不錯的地理位置，但在大陸空運市場逐漸崛起的情況下，整體亞太空運市場分佈稍微向北方偏移，首爾與上海相對於其他亞太各國主要機場受惠更大，更具有發展成為區域轉運中心的競爭優勢。

Airline network design is crucial to an airline’s operation performance and competition. A hub-and-spoke air cargo network system is widely used by airliners for its effect on economies of scale. And the establishment of air transport hub, seen as an engine for growth, has always been an end goal for major airport worldwide for the development of aviation related industries. However, in reality, there are all sorts of fluctuations with seasonal and regional features which affect airline network design and even the long-term strategic choices of air transport hub. Airliners should evaluate and prepare themselves on relevant impacts in advance. This research develops an analytic model by formulating and minimizing the logistics costs to design the hub-and-spoke air cargo network of an airline, instead of using a mathematical programming model, commonly adopted in previous studies, which may not present the feature of economies of scale clearly. The model in this research is capable of reflecting the impacts of cargo time value, aircraft type, cargo flow, relative locations between O/D points and air transport hub on logistics costs. And it plays key effects on the observation of economies of scale on hub-and-spoke air network. Besides, through the model, we can also evaluate the impacts of demand fluctuation on the reliability of aircraft types, flight frequencies and routes. In addition, because of the consolidation effect on major route of hub-and-spoke air cargo network, the fluctuations of cargo flows may be quite severe and the chance of adjusting its optimal aircraft types and flight frequencies may increase as well. This research also designs three scenarios to study the impacts of regional economic development in Asia-pacific region on air network design and even the development of air transport hub, the result in this research turns out that geographical location play more crucial role on the local traffic flows for an airport, if it is going to develop as an air transport hub. Therefore, Seoul and Shanghai benefit the most to become a regional air transport hub among major airports in the Asia-pacific region, due to the rise of Mainland China shifting the air transport market share northwardly.