NA.est                  A function used to construct the Nelson-Aalen
                        estimator.
chernoff_realizations   A dataframe containing computed chernoff
                        distribution
gcm.unique              A function used to remove the repeated numbers
                        for the computation of gcm/lcm.
monotoneHR              Estimate a non-decreasing hazard ratio
                        function, together with a 100(1-alpha)%
                        confidence interval
survData                A right-censored example data
