| 摘要: | 車隊排程與班次表的建立對城際客運業者的營運成本、利潤、服務品質及市場競爭力有相當大的影響。良好的車隊排程和班次表規劃，除了考量客運公司本身的車隊供給及相關營運限制外，亦必須兼顧乘客的反應。然而過去學者在此方面之研究，大多基於預測之平均需求值以進行車隊排程與班次表建立，忽略了實務營運上旅客對於不同客運公司班次表優劣之選擇行為，所造成客運公司市場佔有量變動的特性。此等市場佔有量的變動對規劃的最佳性可能產生相當的影響，若變動性過大，可能造成原規劃的最佳化排程與班次表失去其最佳性。因此，本研究從城際客運業者的立場，考量營運可能發生的市場佔有量變動之特性及實務的營運限制，並以業者最大營運利潤為目標，構建一變動市場佔有量之車隊排程規劃模式。同時，為了比較此模式與以往假設需求固定的排程作法之優劣，本研究另發展一固定需求排程模式。本研究期望能於未來實務的應用上，提供為有效之工具，以期幫助城際客運業者規劃最佳的車隊排程與班次表。 本研究利用網路流動技巧構建變動市場佔有量排程模式，此模式含有多個人流與車流時空網路。在人流網路中，加入旅客偏好選擇模式以定式此一旅客流動問題，並使用一般性網路流動技巧以定式等待旅客在時空中的流動情況。在車流網路中，則以整數流動方式定式車隊於時空中的排程。此變動市場佔有量排程模式可定式為一非線性多重貨物網路流動問題，屬NP-hard問題。此非線性混合整數規劃問題在求解上更難於以往固定需求之排程問題，因此本研究建立一反覆求解架構，以重複修正目標客運公司之市場佔有量，並配合求解固定市場佔有量排程問題以求解模式。最後，為測試本研究模式與求解方法在實務營運中之績效，本研究以國內一城際客運競爭市場的營運資料為例，利用C程式語言結合數學規劃軟體進行實例分析，進而提出研究結論與建議。 Vehicle fleet routing and timetable setting are essential to inter-city bus carriers’ operating cost, profit, level of service and competitive capability in the market. To set a good fleet schedule and a good timetable, a carrier not only has to consider the nature of its fleet and related constraints, but also has to take into account of passengers’ reactions to its service. However, the model was established based on an average passenger demand as input to produce the final timetable and fleet routes, neglecting the variable characteristics of daily market share because of passengers’ choice behavior among different inter-city bus carriers in actual operations, which could affect the optimal fleet routes and timetables. If the market share is wildly changed in daily operations, then the original schedule could be disturbed to lose its optimality. Considering the variable characteristics of daily market share in actual operations, in this research, on the basis of the carrier’s perspective, we developed a variable market share and a fixed demand scheduling model in order to compare the performance with, subject to the real operating constraints, with the objectives of maximizing the carrier profit. The models are expected to be useful planning tools for inter-city bus carriers to solve their vehicle routes and timetables in their short-term operations. We employed network flow techniques to construct the variable market share scheduling model which included multiple passenger-flow and fleet-flow time-space networks. In the passenger-flow networks, we introduced a passengers’ choice model and use generalized network flow techniques to formulate passenger flows in terms of time and space. In the fleet-flow networks, we used integer flow networks to formulate the fleet schedules in terms of time and space. The variable market share scheduling model was formulated as a nonlinear multiple commodity network flow problem that is characterized as an NP-hard problem. This nonlinear mixed integer programming problem is more difficult to solve than the traditional fixed demand fleet scheduling problems. Therefore, we developed an iterative solution framework, in which we modify the target inter-city bus carrier’s market share in each iteration, to reach the eventual solution of a fixed market share fleet scheduling problem. Finally, to evaluate the models and solution methods in practice, we performed a case study using real operating data from a major Taiwan inter-city bus competitive market, with the assistance of C computer programs and a mathematical programming solver, CPLEX. Then show the conclusions and suggestions. |
