A system is preventively renewed at fixed time points τ, 2τ, ... Failures between these time points are removed by emergency renewals. (This replacement policy is called block replacement.) (1) With...

A system is preventively renewed at fixed time points τ, 2τ, ... Failures between these time points are removed by emergency renewals. (This replacement policy is called block replacement.)

(1) With the notation and assumptions of the previous problem, determine the maintenance cost rate K(τ).

(2) On condition that the system lifetime has distribution function

give a necessary condition for a renewal interval which is optimal with res- τ=τ∗ pect to ( K(τ). Hint Make use of the renewal function obtained in example 3.13.)