Extended Evaluation Method for Engineering Alternatives

An improved extended evaluation method of engineering alternatives is proposed by means of extension theory. The matter-element model of the desired alternative (ideal alternative) and the matter-element models of alternatives are established according to decision-makers´ knowledge or practical experience, and then the alternatives can be ranked by extended relational degrees to choose the optimal one(s). The relational degree is a measurement to evaluate how an alternative is close to the desired alternative. The extended evaluation can give sufficient information about the alternatives and overcome some deficiency in conventional fuzzy decision-making problems. Finally, it has been expounded through an illustrative example that the application of the extended evaluation method to the decision-making problem of mechanical alternatives is the feasibility and rationality, and will give designers the theoretical warranty to select the alternatives.