Optimization in container terminals: hierarchical vs integrated solution approaches

Over the last years, international sea freight container transportation has grown dramatically and container terminals play nowadays a key role within the global shipping network. Terminals operations have received increasing interest in the scientific literature and operations research techniques are more and more used to improve efficiency and productivity. In this work we provide an overview of container terminals operations and associated decision problems. We review state-of-the-art optimization approaches in terminals management and we discuss what are in our opinion the current research trends. In particular, we focus on the following streams: the integrated optimization of interdependent decision problems, the analysis of issues related to traffic congestion in the yard and the tactical planning of operations. The discussion is based on the Tactical Berth Allocation Problem (TBAP), an integrated decision problem that deals with the simultaneous optimization of berth allocation and quay crane assignment. Yard housekeeping costs are also taken into account in the objective function. We use the TBAP as a case study to illustrate the benefits of an integrated optimization approach. A comparative analysis with the traditional hierarchical solution approach is provided. Computational results based on real-world data provided by the MCT (port of Gioia Tauro, Italy) show that the additional computational effort required by the integrated optimization approach allows for more efficient solutions.

Optimization of operations in container terminals: hierarchical vs integrated approaches

Michel Bierlaire, Matteo Salani, Ilaria Vacca

Over the last years, international sea freight container transportation has grown dramatically and container terminals play nowadays a key role within the global shipping network. Terminal's operations have received increasing interest in the scientific literature and operations research techniques are more and more used to improve efficiency and productivity. In this work we provide an overview of container terminal's operations and associated decision problems. We review state-of-the-art optimization approaches in terminal's management and we discuss what are in our opinion the current research trends. In particular, we focus on the following streams: the integrated optimization of interdependent decision problems, the analysis of issues related to traffic congestion in the yard and the tactical planning of operations. The discussion is based on the Tactical Berth Allocation Problem (TBAP), an integrated decision problem that deals with the simultaneous optimization of berth allocation and quay crane assignment. Yard housekeeping costs are also taken into account in the objective function. We use the TBAP as a case study to illustrate the benefits of an integrated optimization approach. A comparative analysis with the traditional hierarchical solution approach is provided. Computational results based on real-world data provided by the MCT (port of Gioia Tauro, Italy) show that the additional computational effort required by the integrated optimization approach allows for more efficient solutions.

2010

Yard traffic and congestion in container terminals

Michel Bierlaire, Matteo Salani, Ilaria Vacca, Arnaud Vandaele

In container terminals, the yard is the zone where containers are stored: it serves as a buffer for loading, unloading and transshipping containers. Yard is usually the bottleneck of the terminal, as traffic, congestion and capacity issues mainly originate from there. A berth&yard allocation plan assigns ships to berths and containers to yard blocks: a typical objective is to minimize the total distance traveled by the carriers to transfer containers from the quayside to the yard. Although congestion issues are usually disregarded, operations are often slowed down because of overloaded areas in the yard. In particular, we are interested in evaluating and reducing traffic congestion induced by the berth&yard allocation plan at the operational level. In this work, we firstly present quantitative indicators we devised to measure congestion in the terminal network and to capture its effects on terminals efficiency. These measures are then combined to provide new objective functions, other than traveled distance, which are used in the design of berth&yard templates; a local search algorithm which minimizes congestion is presented. Computational results are analyzed and discussed.

2009

Optimization at Container Terminals: Status, Trends and Perspectives

Michel Bierlaire, Matteo Salani, Ilaria Vacca

International sea-freight container transportation has grown dramatically over the last years and container terminals represent nowadays a key actor in the global shipping network. Terminal managers have to face with an increasing competitiveness among terminals, which require more and more efficiency in container operations both along the quayside and within the yard: the objective is usually to minimize ships turnaround time, one of the main indicators of the terminal performance for the shipping companies. Moreover the minimization of operational costs directly entails the achievement of competitive terminal fares, thus increasing the attractiveness for new customers. Operations research methods and techniques are therefore worth being used in optimizing terminal operations. In this work, we first give an overview of decision problems which arise in the management of a container terminal (e.g. berth allocation, quay crane scheduling, storage policies and strategies, transfer operations, ship stowage planning). Then, starting from a collaboration with some of the busiest ports in Europe, we have identified some critical issues which will be illustrated: in particular, we focus on the impact that gate operations and transshipment operations have on the yard and we propose a new approach to the yard management which takes into account these interactions. We conclude with suggestions of possible research tracks and open issues.

2007