Rick Wing is looking at improving the temperature control on one of his machines. This system currently has four integrated controllers in series:
The reliability of these four controllers are 0.90 (A), 0.92 (B), 0.94 (C), and 0.96 (D).
Rick is looking at installing a back-up for each of the controllers. The back-up controllers all have a reliability of 0.90
a) What is the reliability of the new system which provides a back-up for each of the controllers and what is the percent improvement compared to the current design?
b) Suppose that Rick is considering another back-up design. Here he would create a back-up system in parallel to the current system. This is shown below. The reliability of all four backups, A1, B1, C1, and D1, are each 0.90.
What is the reliability of this back-up design?