Modeling, simulation and optimization in logistics

Abstract

This text summarizes the PhD thesis defended by the author in March 2009 under the supervision of Pasquale Legato at the University of Calabria, Italy. The thesis is written in English and is available for download at the following URL: http://www. trunfio.it/download/thesis.pdf. It aims to explore friendly Operations Research tools for modeling and simulation of logistics processes, with particular interest for mathematical programming models combined with stochastic simulation tools. In particular key assignment and scheduling problems that arise in maritime container terminals are explored. Initially it is presented a study on different modeling paradigms devoted to the representation of logistical processes and the formalization of problems with complex scheduling/assignment constraints. Successively an IP model for managing the assignment of a pool of rail-mounted gantry cranes to berthed vessels is proposed. Then, according to a functional integration approach, a second model centered on the intra-ship scheduling of vessel container bulks to the assigned cranes is further formulated. Finally a simulation-based optimization approach is investigated and the effectiveness of recent search methods is evaluated by comparison with a commercial solver.

Impact of service policies on terminal gate efficiency: a simulation approach

“…Because terminal operations are stochastic and truck arrival patterns are non-stationary, using optimization techniques for this complex model has mathematical limitations, whereas discrete event simulation can deal with the dynamic and stochastic processes (Trunfio, 2011). Thus, simulation of queue models is an appropriate technique for solving queueing problems at the terminal gate.…”