System burn-in can get rid of many residual defects left from componen
t and subsystem burn-in since incompatibility exists not only among co
mponents but also among different subsystems and at the system level,
Even if we perform the system, subsystem, and component burn-in, the s
ystem reliability often does not achieve the requirement, In this case
, redundancy is a good way to increase system reliability when improvi
ng component reliability is expensive, This paper proposes a nonlinear
model to: estimate the optimal burn-in times for all levels determine
the optimal amount of redundancy for each subsystem. For illustration
, a bridge system configuration is considered; however, our model can
be easily applied to other system configurations, Since there are few
studies on system, subsystem, and component incompatibility, we assign
reasonable values for the compatibility factors at each level.