I. Olkin et Yl. Tong, POSITIVE DEPENDENCE OF A CLASS OF MULTIVARIATE EXPONENTIAL-DISTRIBUTIONS, SIAM journal on control and optimization, 32(4), 1994, pp. 965-974
The positive dependence of a subclass of multivariate exponential dist
ributions is examined. This class is characterized by an index vector
k and a parameter vector lambda, which are used as an ordering to yiel
d degrees of positive dependence. The results presented have a direct
implication on the reliability function of a system and the survival p
robability function of a shock model, and consequently on the optimal
assembly of systems.