Abstract Human operators are essential to ensure the safe, effective, and efficient operation of complex dynamic systems.
Operators are often the 'glue' that makes complex dynamic systems work.
Organizational structure and economic pressures often result in control systems defined by a collection of loosely coordinated subsystems some of which are automated. Operators are often the most important mechanism that enables various subsystems to act together as a coherent whole. Operators transfer essential state data, configuration information, or system constraints from one subsystem to another. Operators provide an essential back-up to the control system as a whole and to individual subsystems. That is, automated subsystems may be effective within the specified domain of control, but fail quite seriously when encountering unanticipated circumstances or circumstances which, for financial and organizational reasons, are not included in the system specifications.