A new fuzzy multi-criteria methodology for ranking of alternatives

In this paper a new methodology is given for ranking a finite number of alternatives being described simultaneously by a number of criteria. The criteria are of either benefit or cost type. The criteria values and the relative weights of criteria are either numerical or linguistic expressions defined by fuzzy sets. The ranking philosophy is based on a fuzzy comparison procedure that takes into account both the worst-pessimistic and the best-optimistic criteria values. We describe a decision support system that assists in the ranking of alternatives for various degrees of pessimistic–optimistic index, from the lowest to the highest level of optimism. A real-world autoroad construction problem, which is described by quantitative and qualitative criteria whose relative importance is expressed by numerical or linguistic values, has been considered.