SYSTEMS ENGINEERING METHODS COMPARED

Considerable confusion exists concerning the various methods used in the Function-Requirement-Architecture-Test (F-R-A-T) activities of systems engineering. Functional Flow Block Diagrams, Requirements Allocation Sheets, State Diagrams, N2 Charts, Schematic Block Diagrams, Behavior Diagrams, and others are common. IDEF adds Data Flow Diagrams, Context Diagrams, and Relationship Diagrams. Software analysts have recently created Object Oriented Analysis. From Japan, we get Quality Functional Deployment. These various methods can be compared and contrasted by first using systems engineering to functionally analyze engineering, then looking at the function each method performs. The methods can then be compared and analyzed for the strengths, weaknesses, and application of each. An important conclusion is that the new approaches focus on significantly small subsets of the overall systems engineering analysis tasks. Consequently, serious shortfalls in overall understanding of the system may result if they are the only form of analysis used.