Fuzzing ratings for multiattribute design decision-making

Early in the design process, problems can arise when information is incomplete and goals are not known precisely. When preliminary design evaluation is approached as a multiattribute decision-making problem, both the levels of attributes and their relative importance can be treated as fuzzy numbers elicited from the designer. However, information regarding estimated attribute levels might be lost in limiting the designer to the standard universe of discourse. Another problem is that the attribute weights might be difficult for the designer to determine. A methodology is demonstrated for ranking alternatives based on the fuzzy distance from a fuzzy goal. The concept of a fuzzy line segment is introduced in order to make the universe of discourse continuous, thus not restricting the designer to a small set of fuzzy inputs. The fuzzy line segment makes it possible to more closely reflect the designer's estimates of performance of design alternatives and the relative weight assigned to each attribute. It facilitates more accurate and precise linguistic input, and also provides a way to "fuzzify" numeric input. As a result, Saaty 's Analytic Hierarchy Process (AHP) can be employed to assist the designer in more accurately determining attribute weights.