AMSAA Maturity Projection Model Based on Stein Estimation
Abstract
The reliability growth of a complex system involves surfacing and analyzing failure modes and implementing corrective actions, (termed fixes) during or following a developmental test phase. At the end of a test phase, program management usually desires an assessment of the system's reliability associated with the current configuration. Such an assessment can be derived from failure data observed in the test phase, and assessments of the corrective actions to failure modes surfaced during the test period. Such assessments of system reliability have been referred to as projections. Current projection methods distinguish between failure modes that will be addressed by a fix if observed (termed B-modes) and those that will not be fixed (A-modes). The estimate of current system reliability depends upon this mode classification. In particular, estimates of the rate of occurrence of B-modes based on B-mode first occurrence times and of the presumed constant A-mode failure rate are required to assess system reliability. It would seem desirable and more natural to base the projection of system reliability on estimates that do not depend on such a classification scheme, but merely on failure mode test phase data and the assessed effectiveness of the failure mode corrective actions. Such a projection would only distinguish between failure modes on the basis of their assigned fix effectiveness factors (the expected fraction reductions in the failure mode rates of occurrence due to corrective actions). Modes currently not included in planned or realized corrective actions would be assigned a zero fix effectiveness factor. For situations where fixes to surfaced failure modes will be delayed until the conclusion of the test phase, such a projection method would be helpful in conducting a reliability versus cost tradeoff analysis with regard to deciding which modes to fix.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 2004
- Accession Number
- ADB302442
Entities
People
- J. B. Hall
- Paul M. Ellner
Organizations
- United States Army Materiel Systems Analysis Activity