J. Soc. Korea Ind. Syst. Eng Vol. 9, No. 56-63, September 2016
parture. Under this background, their effects are analyzed
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parture. Under this background, their effects are analyzed by variating flight depart times and lift-up times in the da- ta-setting. The flight departure time was varied from noon set by Kim et al. [3] to 11:40 in decrements of 2.5 minutes and the lift-up time was varied from 300 seconds set by Kim et al. [3] to 260 seconds in decrements of 5 seconds. We generated 10 test problems for each combination of the flight departure time and the lift-up time and randomly set to U(20%, 40%), U(40%, 60%), and U(60%, 80%) of contain- ers arriving at 30~60 minutes before flight departure for non-urgent, moderately-urgent and urgent container arrival situations, respectively. Here, U(a, b) is the uniform dis- tribution with a range of [a, b]. times on the rate of revenue change compared to the original departure time. It can be seen from the figure that the revenue decreased as the flight departure time became earlier as expected. For example, if the flight departure time was changed from noon (original schedule) to 11:40, i.e., 20 minutes earlier than the original schedule, the revenue decreased 0.7%p, 2.2%p, and 4.9%p for non-urgent, moderately-urgent and urgent container arrival situations, respectively. This implies that air express service providers should be cautious when letting their aircrafts depart earlier than the original schedule. Dong-Hoon Son․Hwa-Joong Kim 62 100.2% 100.2% 100.2% 100.9% 100.0% 100.0% 100.0% 100.0% 100.4% 100.4% 100.4% 100.9% 100.3% 100.4% 100.4% 100.6% 100.6% 100.7% 100.8% 100.8% 100.0% 100.1% 100.2% 100.3% 100.4% 100.5% 100.6% 100.7% 100.8% 100.9% 101.0% 300 295 290 285 280 275 270 265 260 Non-urgent container arrival situation Moderately-urgent container arrival situation Urgent container arrival situation Lift-up time (second) Revenue change rate the rate of revenue change compared to the original lift-up time. It can be seen from the figure that the revenue slightly increased as the lift-up time of containers reduced as expected. For example, if the lift-up time reduced from 300 seconds to 260 seconds, i.e., 13% reduction, the revenue increased 0.9%p, 0.9%p, and 0.8%p for non-urgent, moderately-urgent and urgent container arrival situations, respectively. This im- plies that air express service providers should make their effort to reduce the lift-up time and more generally writing to im- prove the productivity of cargo loading operations and ware- housing operations as described in Song et al. [10]. 5. Conclusion This paper revisited a previous study having considered the problem of planning the loading of air express cargoes motivated from DHL and Air Hong Kong. The problem is to determine the locations to be loaded in an aircraft while maintaining its stability. The objective of the problem is to maximize the total revenue obtained from loading con- tainers. The current paper suggested an SA algorithm be- cause our previous research suggested an integer program requiring a long computation time. Computational experi- ments were performed to evaluate the performance of the SA algorithm and derive some managerial implications for air express service providers. The test results showed that our SA algorithm could give good solutions within a short amount of computation time. Therefore, it can be argued that the SA algorithm may be a viable tool for air express carriers including Air Hong Kong needing to quickly estab- lish air cargo loading plans. In addition, scenario analyses showed that air express service providers could experience revenue drop if letting their aircrafts depart earlier than the original schedule and revenue rise if decreasing the container lift-up time. This research can be extended in several ways. First, re- location of containers already loaded in the aircraft should be considered because more containers may be loaded by relocating the containers. Second, it is worthwhile to consider the uncertainty of the cargo weight and arrival time. Third, the problem of jointly determining cargo loading and pack- aging plans is a meaningful research direction. Finally, the problem considering different directions of cargoes is worth- while to be considered. Acknowledgements This work was supported by Inha University Research Grant. An Algorithm for the Loading Planning of Air Express Cargoes 63 References [1] Amiouny, S., Bartholdi, J., Vate, J., and Zhang, J., Balanced loading, Operations Research, 1992, Vol. 40, pp. 238-246. [2] Boeing, World Air Cargo Forecast 2014/15, The Boeing Company Seattle, 2015. [3] Kim, H.-J., Seo, S.-W., Park, M.-Y., and Han, J.-J., An air container loading planning model : DHL and Air Hong Kong case, Journal of International Logistics tải về 0.73 Mb. Chia sẻ với bạn bè của bạn:
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