ROBUSTNESS EVALUATION OF A SEMIPARAMETRIC PROPORTIONAL INTENSITY MODEL

The Prentice, Williams and Peterson (PWP) family of proportional intensity reliability models has been proposed for application to repairable systems. This paper reports results of a study on the robustness of one PWP model over early failure history. The assessment of robustness was based on the semi-parametric PWP model's ability to predict the successive times of occurrence of failure events when the underlying process actually is parametric (specifically a nonhomogeneous Poisson process having power-law proportional intensity function with one covariate). A parametric method was also used to obtain maximum likelihood estimates of the power-law parameters, for purposes of validation and as a reference for comparison.