Understanding Conceptual Design Activities: Extended Axiomatic Theory of Design Modeling and Physiological Experimentation

Conceptual design is an early and critical phase of a design process. Decisions made in this stage can affect seventy five percent of the manufacturing costs. Therefore, one of the important factors to successful production is to have methods and tools that enable designers to work more effectively during the phase of conceptual design. To build such methods and tools, knowledge of design activities such as nature of the design process and factors affecting design activities is indispensable. The present thesis is a continuing effort to build a science of design which aims to discover knowledge of design activities through formal scientific process. The contribution of the current thesis includes the extended Axiomatic Theory of Design Modelling and methodologies to study design cognition physiologically. In particular, two postulates were added to the Axiomatic Theory of Design Modelling to support its explanatory power which was demonstrated through the interpretation of the impact of sketching on design performance and the occurrence of design fixation. An integrated experimental environment was developed to collect and analyze physiological signals during design processes. From this environment, several experiments recording physiological signals were conducted and findings of electroencephalography, heart rate variability, and skin conductance were reported