Knowledge about the process being modeled starts fairly low, then increases as understanding is obtained and tapers off to a high value at the end. - Harold Chestnut

A perennial problem of any organization which is involved in systems work of a changing nature is the need for the organization itself to change as it adapts to new opportunities, new objectives, new equipment, and new people.

In a society which is producing more people, more materials, more things, and more information than ever before, systems engineering is indispensable in meeting the challenge of complexity.

A model is a qualitative or quantitative representation of a process or endeavor that shows the effects of those factors which are significant for the purposes being considered. A model may be pictorial, descriptive, qualitative, or generally approximate in nature; or it may be mathematical and quantitative in nature and reasonably precise. It is important that effective means for modeling be understood such as analog, stochastic, procedural, scheduling, flow chart, schematic, and block diagrams.