K. Zhang, G. Bedette, R. F. DeMara, "Triple Modular Redundancy
with Standby (TMRSB) Supporting Dynamic Resource Reconfiguration," 
in Proceedings of IEEE AUTOTESTCON 2006, September 18-21, 2006.

Abstract - A fault tolerance model called Triple Modular 
Redundancy with Standby (TMRSB) is developed which combines 
the two popular fault tolerance techniques of Triple Modular 
Redundancy (TMR) and Standby (SB) fault tolerance.  In TMRSB 
systems, each module of a TMR arrangement has access to several 
independent standby configurations. When a fault is detected in 
a module’s active configuration, the physical resources within 
that module are re-mapped to restore the desired fault-free 
functionality by reconfiguring the resource pool to one of 
the standby configurations.  A mathematic model for TMRSB 
systems is developed for Field Programmable Gate Array (FPGA) 
logic devices. Simulation of the model was also performed using 
the BlockSim reliability software tool which takes into account 
the reconfiguration time overheads and an imperfect switching 
mechanism.  With component time-to-failure following an 
exponential distribution throughout long mission duration, the
range of operation over which TMRSB is superior to a Standby 
System and a TMR system is shown.