Abstract: This metric is the ratio of the maintenance personnel who are actively doing the maintenance work (direct) to the maintenance personnel supporting the maintenance work (indirect). Direct personnel include those workers in the maintenance department that repair, maintain, modify or calibrate equipment.
MIDI (Musical Instrument Digital Interface) is a protocol designed for recording and playing back music on digital synthesizers that is supported by many makes of personal computer sound cards. Originally intended to control one keyboard from another, it was quickly adopted for the personal computer.
Other common MIDI controllers are wind controllers, which a musician blows into and presses keys to transmit MIDI data, and electronic drums, which are typically struck with sticks to create MIDI data. MIDI controllers do not usually create or produce musical sounds by themselves.