SRC Forum - Message Replies
Forum: Reliability & Maintainability Questions and Answers
Topic: Reliability & Maintainability Questions and AnswersTopic Posted by: Reliability & Maintainability Forum (firstname.lastname@example.org )
Organization: System Reliability Center
Date Posted: Mon Aug 31 12:47:36 US/Eastern 1998
Posted by:C.P. Chuah
Subject: Purpose of predecessor system
The PRISM program accommodates this type of analysis through the use of its "Predecessor System/Assembly Analysis" function, available to the user from the relevant "Failure Rate" folder tab. The "Predecessor Analysis" function uses the PRISM-based reliability prediction of the predecessor product, and the observed field failure rate associated with that product, as a basis for estimating the reliability of the new system or assembly.
In order to use the Predecessor Analysis function of the program, there are 3 prerequisites that must be met:
1. The Predecessor system/assembly must have a PRISM-based reliability prediction performed on it (i.e., it must be defined within the PRISM System Manager).
2. The reliability prediction of the Predecessor must be fully summarized at the appropriate level, (i.e., system or assembly (a "Not Summarized" message must not be present on the "Failure Rate" folder tab of the Predecessor system/assembly)).
3. The Predecessor system must have observed failures and observed cumulative calendar hours available for it. Furthermore, each of the assemblies defined within that system must also have observed failures and cumulative calendar hours available for it. The "Observed Failures" and "Observed Cumulative Calendar Hours" are entered by the user using the Predecessor "Failure Rate" folder tab.