Aircraft ground service scheduling problems and their genetic algorithm with hybrid assignment and sequence encoding scheme

The aircraft ground service is a key ring to guarantee flight safety and normal operation. In the case of the traveling time of service crew from one aircraft parking place to another to be nonignorable, the scheduling optimization problem of ground service can be described as a vehicle routing problem with time windows of multiply nonidentical vehicles. To solve the problem, we propose a genetic algorithm with a hybrid encoding scheme. The encoding scheme describes the bit of a chromosome as a positive real number. Its integer part stands for the assigned crew of a flight and its decimal part for the position in job sequence by percent. The encoding scheme integrates assignment and sequence information in one number. Thus, it can be conveniently processed by all genetic operations of crossover, mutation, selection, and reproduction. A greedy heuristic is embedded as the sequencing initialization and reinitialization tool in the genetic algorithm procedure. The genetic algorithm is used to solve a lot of examples from a practical aircraft service company. The achieved results show that the algorithm is efficient.