Optimal operations of transportation fleet for unloading activities at container ports

This paper presents mathematical models that optimize the size of transportation fleet (cranes and trucks) for unloading operations at container terminals. A cyclic queue model is used to study the steady-state port throughput, which then yields the optimum fleet size for long-term operations. This model allows for stochastic operations such as exponentially distributed crane service times. In order to allow for generally distributed crane service times and truck travel times, an approach based on Markovian decision process is also proposed. This model provides dynamic operational policies for fleet management. Both models are implemented and examined with empirical data from the Port of Balboa, Panama. These models are also extended to unloading operations that involve multiple berths.