8.
Assessing Product Reliability
8.1. Introduction


Models for repair rates of repairable systems 
\(N(t)\), \(M(t)\), and \(m(t)\)
were defined in the section on Repair Rates. Repair
rate models are defined by first picking a functional form for \(M(t)\),
the expected number of cumulative failures by time \(t\).
Taking the derivative of this gives the repair rate model \(m(t)\).
In the next three sections we will describe three models, of increasing complexity, for \(M(t)\). They are: the Homogeneous Poisson Process, the NonHomogeneous Poisson Process following a Power law, and the NonHomogeneous Poisson Process following an Exponential law. 