in a condition-based maintenance (CBM), the decision to maintain is based on equipment or system degradation.

1- Suggest four possible indicators for system/equipment health or degradation level that we can measure.

2- Suggest two processes that can model the degradation process?

3- Suggest two objective functions that can be used as art in optimization model that determines the optimal condition-based maintenance.

4- Suggest two solution approaches we can use to determine the optimal policy for the CBM.