Research by Dr. Xinjia Jiang that studied an interesting Frame Trolley (FT) dispatching problem for the Frame Bridge Based Automated Container Terminal was publicized in Transportation Science on April 2018. Transportation Science is a flagship journal of INFORMS, and one of the top two journals in the transportation area. It focuses primarily on fundamental theories, coupled with mathematical models, advanced methodologies, and novel applications in transportation and logistics systems analysis, planning, and design. “Modeling the movement of FTs and the usage of bridge rails will be one of the most challenging issues in our study,” the authors noted. Abstract is copied below.
We address the Frame Trolley (FT) dispatching problem to ensure conflict-free movements, while considering the handshakes with other devices in the system. A mixed-integer programming (MIP) model is formulated to minimize the makespan considering FT conflicts and handshakes. An algorithm based on filtered beam search is developed to solve the problem. In this algorithm, two filtering approaches are used to guide the search for beam nodes at each level. The first approach uses a surrogate model to effectively screen out the less promising nodes. Then, the second approach uses a reduced MIP model to further identify the beam nodes for the next level. Numerical experiments show that our proposed algorithm yields near-optimal solutions in small-scale problems. In large-scale problems, our algorithm significantly outperforms two other algorithms based on first come first served (FCFS) or FCFS with dedicated vehicle assignment. Some interesting insights about the FB-ACT system are also shown in the study. The general modeling concept is shown in Figure 1.

 
Figure 1. The Modeling Concept for Order and Timing of Two Exemplary Events

Read the paper “Frame Trolley Dispatching Algorithm for the Frame Bridge Based Automated Container Terminal,” published in Transportation Science.