Investigation into yard slots scheduling using heuristic algorithms

Yard, forming a distributed system with automobile manufactures and the most important resource in the automobile terminal, significantly affects the efficiency of an automobile terminal. As the amount of vehicle arriving terminal changes due to time, the scheduling of yard slots becomes critical to automobile terminal yard management. In order to improve automobile terminal yard management, an allocation model of yard slots was proposed using integer programming. To resolve the NP-hard problem pertaining to the yard slots scheduling, two heuristic two- stages algorithms, the mixed algorithm and the idlest priority algorithm were employed. A simulation system of one automobile terminal was built with SQL 2005 and Anylogic to compare the two heuristic algorithms on the base of the history data. The result of simulation: the concentration of the mixed algorithm was equal to the concentration of the idlest priority algorithm but the utilization ratio of the mixed algorithm increased by 73.61% comparing with the idlest priority algorithm. Accordingly, the mixed algorithm, relocating the vehicles exceeding expectation in some rules and scheduling slots in the zone, can be used to instruct the work of scheduling yard slots in order to improve the avenue of terminal.