A new integrated design concept evaluation approach based on vague sets

Design concept evaluation which is in the end of conceptual design is one of the most critical decision points in product development. It relates to the final success of product development, because a poor design concept can rarely be compensated at the later stages. Design concept evaluation is a complicated multi-criteria decision-making problem under uncertain environments. Vague set theory is superior to fuzzy set theory in dealing with uncertain and imprecise judgments of decision makers (DMs) due to its ability of supporting opposing evidences. In this paper, a new integrated design concept evaluation approach based on vague sets is presented. Linguistic variables are transformed into vague numbers by vague set theory. Modified weighted least squares model (WSLM) based on vague sets is proposed to aggregate all individual judgments in group decision-making. Vague cross-entropy integrated with the technique for order preference by similarity to ideal solution (TOPSIS) framework is proposed to rank the order of alternatives according to the synthetic vague decision matrix. Numerical example of design concept evaluation problem of a horizontal directional drilling (HDD) machine indicates that the proposed integrated approach is systematic and effective to solve design concept evaluation problem regardless of complexity of product.