Prognostics and Health Management: A Review on Data Driven Approaches

Table 2

Summary of three stochastic processes.

Models	FHT distributions	Model parameters	Shapes of hazard functions
Wiener process	Inverse Gaussian distribution	Drift and variance	Upside down bathtub
Gamma process	Approximate inverse Gaussian or B-S distributions	Shape and scale	Upside down bathtub
Inverse Gaussian process	Approximate B-S distribution	Mean and shape	Upside down bathtub