The total time on test transform and the decreasing percentile residual life aging notion

Recently Nair and Sankaran (2013) listed some known characterizations of common aging notions in terms of the total time on test transform (TTT) function. They also derived some new characterizations. The purpose of this note is to add two characterizations of the decreasing percentile residual life of order αα (DPRL(αα)) aging notion in terms of the TTT function, and in terms of the observed TTT when XX is observed.