System performance, degradation, and reliability assessment

Degradation test and analysis provide the information to assess the reliability of a system. On-line degradation monitoring can be adopted for real-time system performance reliability or survival prediction. This paper discusses the concepts of system performance, degradation, and system performance reliability assessment. The off-line degradation data analysis for estimating time-to-failure distributions with asymptotic variances, and the on-line performance degradation for reliability assessment and prediction with time series are reviewed and discussed. The off-line method is useful to the estimation of time-to-failure distributions for those components with extremely high reliability, whereas the on-line method can be applied to those systems in which degradation may result in a sudden catastrophic system failure. The statistical methods in the two situations are discussed.