The target system of this study is the operation and maintenance system
of ROK Naval ships. Finding out what elements are included in the system
is important in determining root causes. Brain storming or mind-map can
be used. This process requires expert opinion. This is because it is
necessary to determine the root causes by identifying the relationships
among various influencing factors included in the system (Section 2.1).
Root causes are analyzed using statistical models such as Bayesian
inference, phase-type distribution, linear/multi regression, SD
simulation models, existing theories about human work speed, and survey
results (Section 2.2).