Closed System: It's isolated from environment influences. It operates on factors within System itself. It is also described as a System which involves a feedback loop, a control element as well as feedback performance standard. 

Performance Standard is defined as objective that System has to meet. A Feedback loop is defined as a part of the System which allows the System to regulate itself. Signals are attained from the System describing the System Status and are transmitted to Control Mechanism. A Control Element compares output with the performance standard and adjusts system input consequently.