A 2-PHASE ASPIRATION-LEVEL AND UTILITY THEORY APPROACH TO LARGE SCALE DESIGN

The ability to make rational decisions is one of mankind's unique attributes. A characteristic of the formal techniques that have been used for decision making is the selection of the best alternative with respect to a certain figure of merit. One of the most critical problems in engineering design is making early decisions on a sound basis. However, the early stages of design are also the most uncertain, and obtaining precise information upon which to base design decisions is usually impossible. The need for a methodology to represent and manipulate imprecision is greatest in the early, preliminary stages of engineering design, where the designer is most unsure of the final dimensions and shape, material properties, and performance of the completed design. Utility Theory provides an analytical way to aid the decisions in engineering design. By exchanging from objective to attribute and expressing these attitudes mathematically, a utility based attribute function (Utility Function) can be set up to describe the attitude of a decision-maker with regard to his/her preference. In this work, the Aspiration-level Interactive Method (AIM), a goal-seeking method based on identifying non-dominated solutions, is used along with Utility Theory to compensate for the limitations of utility theory in forming a meaningful group preference. This work is an initial attempt to integrate two methodologies from the field of decision theory in order to provide rational decision support for design problems where a hierarchy of decision making is required. The hierarchy, in this paper, is characterized by multiple designers at the lower level who report to one manager. The designers each have different preferences and values, while the manager is driven by project goals and specifications. The approach presented generates feasible and preferred design combinations for further analysis in the detailed design phase.