Equipment Sizing using Petri Networks


Ports have become freight distribution hubs. Due to fierce regional and international competition, port operators seek ways to maximise terminal throughput and productivity. This paper uses queuing theory, Petri Networks (PNs) and discrete event simulation to compare the impact on the productivity of yard-side operations in a container terminal of utilising different numbers of Automated Straddle Carriers (AStCs). PNs and discrete event modelling techniques divide complex continuous systems into subsystems and analyse the system as a series of sequential operations being performed on certain entities. Discrete event simulation is used for the utilisation of AStCs with gang and pooling deployment strategies. Venice’s new off-shore terminal is used for modelling the complex processes of a container terminal in order to determine the optimal number of AStCs. The equipment sizing results gained from the developed PN and discrete event simulation are closely matching with the optimal solution determined from various models of queuing theory. Given the different effort required for the three methods, it can be concluded that PN represents a fair trade-off and is the methodology of choice for equipment sizing problems, compared to analytic queuing theory and complex discrete event simulations.

Annual Meeting of the Global Ports Research Alliance (GPRA)