Statistics for Maintenance Modelling: Renewal Processes

# The Renewal Function and Renewal Density¤

The expected number of events by time t, M(t) = E{N(t)}, is called the renewal function. Its derivative v(t) = dM(t)/dt is called the renewal density.

As examples of typical renewal functions and densities, the charts below show the renewal function and renewal density for an Erlang(4) distribution (the theoretical calculation will be shown later). The pdf of the Erlang(n) is: