| dc.description.abstract | Fleet routing and flight scheduling are important in carrier’s levels of services and operational performance. They always affect the usage efficiency of facilities and crew scheduling. As a result, they are essential to carriers’ profitability, level of service and competitive capability in the market. In the past, most research on airline scheduling was mainly focused on passenger transportation, which is fundamentally different from express package delivery. In passenger transportation, passengers are more sensitive to time than express cargos. Too many transfers in a transport service may result in a significant loss of passengers. However, in air express service, as long as the package arrives on time, the customer would not care how it is routed. Currently, the hub-and-spoke network is mostly adopted by express cargo carriers, which is different from general passenger air transportation networks. Besides, due to the consideration of timelines operations at each station, there are usually time window constraints for express cargo delivery. Because of the time window constraints, the operating costs of cargos at each airport and the hub are negatively related to their handling times. Therefore, considering the operating cost at each airport, carriers must arrange suitable flight arrival/departure times in order to lower operating costs. Although there was a scheduling model recently developed for general air cargo transportation, it was not developed on the characteristics of express package delivery.
Therefore, on the basis of the carrier’s perspective, this research develops a short-term scheduling model for international express package delivery, with the objective of minimizing the operating cost, subject to the related operating constraints. The model is expected to be a useful planning tool for air express carriers to determine a suitable fleet routing and timetables in their short-term operations. We will employ network flow techniques to construct the model, which will include multiple fleet time-space networks in order to formulate the fleet flows in the dimensions of time and space. We consider the relation between the handling time and the operating cost at each airport and introduce the alternative flight arcs into the time-space networks to decide on the best flight departure/arrival times. The model is expectedly formulated as a integer multiple commodity network flow problem that is characterized as an NP-hard problem. We use C computer language and a mathematical programming solver to develop an efficient algorithm to solve the problem. Finally, to evaluate the model and the solution algorithm, we perform a case study by using the real operating data from a major international air express carrier. The results indicate that the model works well and is useful in actual operations. | en_US |