Scheduling Under Uncertainty for a Single-Hub Intermodal Freight System

摘要

This paper deals with optimization of an intermodal system with freight transfers at one hub. Thequestion analyzed in this research is to determine when departures should be scheduled on outboundroutes, given information about the probabilistic arrivals of vehicles on inbound routes.The intermodal system is modeled using stochastic programming and the schedule of outboundvehicles is optimized with a genetic algorithm. The model is designed to minimize the expectedtotal cost of operating an intermodal system, while considering all the capacity constraints arisingin the real-world. This model allows the system performance to be computed numerically,without the approximations of alternative methods such as simulation. Although it can be appliedto the most general case, the model seems to be especially suitable for analyzing systems withrelatively small number of arrivals on inbound routes. In particularly, the model can be successfullyapplied to situations when statistical or queuing analyses are not applicable due to the smallnumber of events (vehicle arrivals). We specifically analyze an intermodal system consisting ofmultiple inbound truck routes and multiple outbound airline routes. However, the mathematicalmodel developed in this paper is applicable to other combinations of transportation modes.