MAD – See Mean Absolute Deviation (MAD).
maintenance – The work of keeping something in proper condition, upkeep, or repair.
Maintenance activities can be divided into three types: emergency maintenance, preventive maintenance, and predictive maintenance. Emergency maintenance is an unplanned maintenance problem that often results in lost productivity and schedule disruption.
Preventive maintenance is the practice of checking and repairing a machine on a scheduled basis before it fails; also called preventative maintenance. The maintenance schedule is usually based on historical information on the time between failures for the population of machines. In contrast, emergency maintenance is where maintenance is done after the machine fails. In ...