On weighted lower and upper possibilistic means and variances of fuzzy numbers and its application in decision

摘要

In this paper, we define the weighted lower and upper possibilistic variances and covariances of fuzzy numbers. We also obtain their many properties similar to variance and covariance in probability theory. On the basis of the weighted lower and upper possibilistic means and variances, we present two new possibilistic portfolio selection models with tolerated risk level and holdings of assets constraints. The conventional probabilistic mean–variance model can be transformed to a linear programming problem under possibility distributions. Finally, an estimation method of possibility distribution is offered and a real example for portfolio selection problem is given to illustrate the usability of the approach and the effectiveness of our methods.