  In this article we consider a simple step stress set up under the cumulative
exposure model assumption. At each stress level the lifetime distribution of
the experimental units are assumed to follow the generalized exponential
distribution. We provide the order restricted Bayesian inference of the model
parameters by considering the fact that the expected lifetime of the
experimental units are larger in lower stress level. Analysis and the related
results are extended to different censoring schemes also. The Bayes estimates
and the associated credible intervals of the unknown parameters are constructed
using importance sampling technique. We perform extensive simulation
experiments both for the complete and censored samples to see the performances
of the proposed estimators. We analyze two simulated and one real data sets for
illustrative purposes. An optimal value of the stress changing time is obtained
by minimizing the total posterior coefficient of variations of the unknown
parameters.
