GROUP INTERVAL WEIGHTS BASED ON CONJUNCTION APPROXIMATION OF INDIVIDUAL INTERVAL WEIGHTS
The individual and group decisions in this study are denoted as the normalized interval weights of alternatives as in Interval AHP. It assumes that a decision maker uses crisp values in the interval weights in giving comparisons. The interval weights reflect uncertainty in a decision maker’s mind. Then, the group interval weight is obtained as a conjunction approximation of the individual interval weights. For a consensus, the group interval weight is obtained so as to intersect with all the individual interval weights. In other words, the group interval weight has something in common with each individual interval weight. The group decision depends on how much the decision makers are satisfied or dissatisfied with it. The satisfaction of a decision maker is measured by the ranges of the group interval weights which s/he can support. Similarly, the decision maker’s dissatisfaction is defined by the ranges which are out of his/her decision. It is better to maximize the satisfaction and simultaneously to minimize the dissatisfaction. However, there is a trade-off between these two objectives. In the proposed model, the importance of the satisfaction or dissatisfaction is given. Then, the decision makers find not only the group decision but also their satisfaction and dissatisfaction with it.