Title: Combining relocation and pre-processing moves in container terminal operations
Speaker: Bernard Zweers (CWI)
Abstract: In container terminals, containers are stacked on top of each other to save space. Since there is uncertainty about the moment when a container will leave the terminal, it often happens that other containers are stacked on top of this target container. These containers have to be relocated to other stacks to retrieve the target container. In this relocation phase, the containers are placed in the stack for which the future expected number of relocation moves is the lowest.
We introduce a problem that is faced by a container terminal in the port of Amsterdam. At this terminal, the crane operator has sometimes some idle time in which pre-processing moves could be done. However, the idle time is limited so there is a constraint on the number of pre-processing moves that can be done. The goal of our problem is to find the pre-processing moves that result in a bay with the lowest expected number of relocation moves. We propose a heuristic to solve this problem and compare the results with an optimal branch-and-bound algorithm.
Title: A Robust Optimization Approach to Synchromodal Container Transportation
Speaker: Irina Chiscop (TNO and Delft University of Technology)
Abstract: This work addresses synchromodal planning at operational level from the perspective of a logistics service provider. The existing infrastructure and the transportation activities are studied and modeled as an optimization problem with simultaneous vehicle routing and container-to-mode assignment. A special characteristic of this problem is the uncertain data. In other words, it is assumed that the release times of the containers belong to an uncertainty interval, and no further statistical information is available. The container routing problem is modeled as a mixed integer program with explicit time variables and lateness penalties. A robust formulation is then proposed to eliminate the uncertain parameters from the objective function and constraints. The resulting two-stage decision model is tested for a small-sized instance, providing worst-case evaluations of the transport planning.
Title: Real-time Synchromodal Transport Planning
Speaker: Rie Brammer Larsen (Delft University of Technology)
Abstract: The synchromodal transport scheme gives transport providers full control over the transport planning and execution, as long as the agreed upon deadline is met. They are thus able to adjust the plans every time new information is received, both for upcoming transport demand and freight that has already left its origin. If suitable planning methods are used, this flexibility has the potential to improve the efficiency, cost and sustainability of transport. When plans are made based on real-time information, decisions can change quickly and it becomes important to consider the locations of both freight and vehicles . We use a model predictive controller to plan and execute freight and vehicle movements in 15 min intervals on a simulated hinterland container transport network. The results show that simultaneous planning of container and vehicle movements not only ensures that vehicles are available when needed but also decreases the fluctuation in the number of vehicles needed. The results furthermore illustrate how a model predictive control approach responds to uncertain travel times and demand.