Guizzi et. al propose a model of a productive system subject
to a condition based maintenance policy which has to be
optimized by modifying the maintenance thresholds to reach
the lowest level of global system cost. A simulation approach
is proposed that take in count all the cost related both to
production and to maintenance. They propose a parametric
study to determine how some critical parameters can influence
the achievement of the system and the maintenance policy to
be adopted [17].