  In this paper, we discuss stochastic comparisons of parallel systems with
independent heterogeneous exponentiated Nadarajah-Haghighi (ENH) components in
terms of the usual stochastic order, dispersive order, convex transform order
and the likelihood ratio order. In the presence of the Archimedean copula, we
study stochastic comparison of series dependent systems in terms of the usual
stochastic order.
