2.3 THE SEMIOTICS OF ENGINEERING DESIGN
In the many illustrations above involving the ASE design cycle, the information flow is counter-clockwise. The counter-clockwise flow was chosen because there exists a "right-hand rule" in mechanics that states that as the fingers of the right hand curl to follow the direction of rotation, the torque orthogonally follows the direction of the thumb. A tool metaphor was chosen for the ASE model, with the direction of torque analogous to a positive movement of the system toward a the design goal. On the other hand, the design flow could have been depicted traveling clockwise, a direction to which many people are more accustomed from years of watching time pass on clock faces.
It must be noted that torque is a vector directed along the rotational axis, a mathematical construction, and it being positive or negative is merely a convention adopted by engineers. The clockwise convention of the clock face is more naturally based on the progress of the shadow cast by the gnomon on a sundial as the sun moves across the northern hemisphere. The adoption of the convention of torque is due to the natural predominance of the right hand. The direction of a screw's threads spring from this convention, requiring a clockwise application of force to embed the screw or lift water, and a counter-clockwise application of force to loosen the screw or discharge the water.
Conventions and standards are an important part of engineering design. They permit an unobtrusive means to concur on the meaning of aspects of design without the potential rancor of debate. Within the different disciplines of the engineering environment, conventions as embodied by language, often evolve autonomously. Yet, for communication between discliplines, conventions must extend across domains, or translations between domains should be such that meaning is preserved [Lee & Malone 88].
Preservation of meaning invariably depends on a consistency of interpretation by the concerned agents. This consistency of interpretation is either explicitly or implicitly agree to by convention. Conventions can be effectively employed to facilitate communication throughout all aspects of concurrent design. A field of literature known as semiotics attempts to address the basic element of convention, the sign, and the system that is developed around this element.
Semiotics is a science of the "sign". Charles S. Peirce, regarded as an originator of modern semiotics, wrote that a "sign, or representamen, is something which stands to somebody for something in some respect or capacity." [Peirce 85] With such a broad definition, examples of signs abound. A red traffic light is a sign that stands to drivers as a requirement to stop their automobiles. A turning weather vane is a sign to an onlooker that the direction of the wind is changing. A utility curve sketched on paper is a sign to an economist of consumer preferences.
Semiotics is a field of study that analyzes sign systems, with an underlying contention that "meaning" is construed by social convention. None of the signs in the examples above would have had meaning were there not agreement on their use. Even "natural" signs can be seen to convey meanings only by social convention.
Semiotics is the successor to "Structuralism", which is a methodology whereby large-scale systems are analyzed in terms of the functionality and inter-relationship of their smallest components. Developed within the field of linguistics under Ferdinand de Saussure, structuralism emphasized the structure over the individual constituent. Grammar, rules, and other models were emphasized over individual usages or data. As such, focus is on the system, culture, and deep structures rather than superficial manipulation of the elements [Holdcroft 91].
The focus on the sign in semiotics is akin to the focus on the symbol in symbolic computing. The representations computers manipulate are no longer as tightly bound by the mechanics of the machine as they once were. It has only been since the late 1980's that computing platforms which invoke strategies of symbolic processing became commonly available. Techniques using involving fourth-generation languages, object-oriented programming, graphical user interfaces, and production systems represent the liberation of thought from the underlying mechanics of the computer. Only until recently have sufficient tools with which to implement the speculations of semiotics upon a computational workbench been made available.
There is a century's worth of literature to be found in the field of modern semiotics. The topic is well thought-out and discussed and has found application in almost all areas of the liberal and fine arts. Its approach is methodical and concise, and comes from a background of obedience to a strict, behavioristic code. The virtual environments of engineering design can be viewed as having little difference from the virtual worlds created by literature and the fine arts (although engineering attempts a more rigorous modeling of an empirically provable world). With the advent of the symbolic processing and extensive networking that virtuality demands, the computing environment is at a point where the literature of semiotics must be seriously perused, lest years be spent rediscovering ideas which had been methodically formulated over half a century before.