TABLE OF CONTENTS This chapter covers several variations on simple functional flow diagramming applied in Chapter 3.2. These variations fall into six categories: (1) functional analysis variations, (2) state diagramming in several forms, (3) mathematical methods, (4) scenarios, (5) process analysis, and (6) quality functional deployment (QFD). Part 4 covers several computer software models including a new Department of Defense standard on complex information system architectures called DOD AF.
There are several models that include a functional sequence but also apply a kind of lateral axis as well representing data or commodity flow. These two-axis models are substantially richer in modeling a problem space than simple functional flow diagramming but the reader is cautioned that they are also not as effective in communicating modeling results into the human mind through the sense of vision because they are more cluttered on the page they are visually more complex.
This book encourages the use of functional flow diagramming as the preferred method for gaining insight into needed system functionality. It is, however, possible to decompose the system need using a hierarchical function structure as illustrated in Figure 3.9-1. Two levels of the diagram are illustrated to show how it can be decomposed. Each block on this diagram represents the same thing described for functional flow diagram blocks earlier but the diagram does not disclose intended sequence, simultaneity, or relative timing.
Where a system, or system element, is characterized by a...
