2 An Integrated Model for Characterizing & Managing System Architectures

The term “architecture” is widely used in systems engineering circles, but the explicit meaning of the term varies considerably from person to person, depending on expertise and viewpoint. A previous paper (Steiner '98) defined the term with respect to system evolvability. This paper attempts to clarify architectural characteristics by defining three orthogonal axes: Expression (form/function), Permanence (enduring/transitory), and Abstraction (abstract/concrete). Segregating a given architectural concept into these three key areas of concern facilitates a balanced approach to managing system architectural models. It can also logically be extended as a mechanism for clear communication among stakeholders.