| dc.description.abstract | Abstract
In recent years, international air express services have grown rapidly. The markets become very competitive for the carriers. Since air express services rather emphasize on time-definite deliveries, it is important for carriers to efficiently to collect, classify and assembly cargos at every service station. In which, the cargo container loading operation, in general, significantly affects the total operating time and cost. As a result, how to determine a suitable cargo container loading plan in order to minimize the operating cost is an important issue for air express carriers. Since the cargo container loading plan is related to the operating cost of each airport and the hub, which is further nonlinearly correlated with the assignment of cargos to pure/mixed containers, the cargo quantity and their allowable operating times, the cargo container loading plan problem is very complicated. However, the current cargo container loading plan in practice is solved manually with staff’s experience, which is neither effective nor efficient, especially for the environment of large hubs and complicated network operations today. As to academics, there has not yet research found on the cargo container loading plan problem of international air express cargos. Therefore, on the basis of the international air express carriers’ perspective, this research develops a cargo container loading plan model, with the objective of minimizing total cost, subject to related operating constraints. The model is a useful planning tool for International air express carriers to decide on their cargo loading plans in order to lower their operating costs, so that their profits and market competitiveness can be enhanced. The model is formulated as a nonlinear mixed integer program that is characterized as NP-hard and is more difficult to solve than integer linear programs, especially for realistically large-scale problems that cannot be optimally solved in a reasonably short time. Since the model’s objective contains nonlinear ladder-functions, we convert them into piece-wise linear functions. Furthermore, we employ C computer language, coupled with a mathematical programming solver, CPLEX, to develop an efficient algorithm to solve the problem. To evaluate the model and the solution algorithm, we perform a case study using real operating data from an international air express carrier. The results are good. | en_US |