Microsimulation Models in a RO-RO High Speed Services Intermodal Container Terminal: Ordinary and Perturbed Conditions
Vincenzo Assumma, Antonino Vitetta, University Mediterranea of Reggion Calabria, IT
This paper proposes a method for simulating loading/unloading operations by using a rail system in a RO-RO High Speed Services intermodal container terminal by means of deterministic and stochastic models.
The significant development in recent years of container transport, in terms of technology and organization, has led to profound changes in international transportation. Ports appear to play an ever greater role, and the minimization of operation times in the maritime node is a fundamental factor for justifying the use of RO-RO High Speed Shipping Services for freight transport, as against the vessels currently used.
The basic aim in RO-RO High Speed Services terminal management is to reduce ship waiting times from arrival to departure by minimizing loading/unloading times. This problem has already inspired many researchers to develop innovative loading/unloading systems in container terminals, for instance integration between road transport and RO-RO High Speed Services transport ships by using rail systems for loading/unloading operations.
In the last few years discrete-event simulation models in the object-oriented approach have been proposed as decision support systems, with reference to maritime container terminals. The object-oriented approach has been particularly useful to describe logistic integration of the main system terminal modules (Land gate, Yard Container, Berth). Recently, a state-of-the-art container terminal was proposed by Vis and Koster (2003) and Steenken et al. (2004), with a description and classification of the main logistic processes and operations in container terminals and some methods for their optimization.
This paper proposes a method for simulating loading/unloading operations by using a rail system in a RO-RO High Speed Services intermodal container terminal by means of deterministic and stochastic models; the method consists in specifying the models represented by nodes, links and times for the single operations, so as to be able to control critical events, namely the possibility of breakdown or failure that affects ordinary operations in a intermodal container terminal. Every model is specified by definition of the variable and is described in terms of input and output. From the simulations of the models, instead, we derive the output, essential to assess system utility, expressed by loading/unloading operation times.
The paper contains:
? a short introduction to the problem and an updated review of current models in the literature;
? an analysis of container terminals and the simulation methodology and models used concerning the main logistic processes and operations in container terminals;
? an explanation of ordinary and perturbed conditions, that is the possibility of breakdown or failure that influences ordinary operations in the intermodal container terminal;
? the application to land-side operations in a RO-RO High Speed Services intermodal container terminal, simulating both ordinary and perturbed conditions; the ordinary conditions are explained by means of a deterministic disaggregate model, the perturbed conditions by means of stochastic disaggregate model, with a Gamma distribution function. For the experimentation we use a procedure implemented by the software "ARENA" of Rockwell Software, a microscopic discrete-event simulator.
Some interesting results emerge from the analysis of the outcome, in particular combining deterministic and stochastic times under different scenarios, even if they are still subject to revision and integration, for instance by modifying terminal structure and handling equipment.
Association for European Transport