3.3. Add maintenance technology and schedule pressure module
It is difficult to complete the maintenance of a ship 100% perfectly. In other words, it is difficult to return to the same condition as new after maintenance. The repair shop’s technical skills and natural aging are the reasons for this. Maintenance technology refers to this phenomenon. Choi and Moon (2021) estimated the technical level of Naval ship’s repair shop by Bayesian inference. On average, it was repaired at a level of 74%. If maintenance is performed with 100 failures, 26 failures cannot be completely repaired and remain on the ship. On the other hand, Oliva and sterman (2001) studied that the speed of a person’s work varies by 75~125% depending on the workload. Mechanics can perform maintenance faster when there is a lot of work and more slowly when there is less work. The standard working day for the Navy is 8 hours. When they are busy, they can perform 10 hours’ worth of maintenance (8*1.25). The disciplines were applied using system dynamics. The model in Fig. 7 includes disciplinary (schedule pressure) and maintenance technology (Effective of maintenance). Although the scales of all modules are different, building them into one model is not different from the process of building a system dynamics model in general.