IEEE Transactions on Reliability

As an alternative to traditional life testing, degradation tests can be effective in assessing product reliability when measurements of degradation leading to failure can be observed. This article proposes a new model to describe the nonlinear degradation paths caused by nano-contamination in plasma display panels (PDP): a bi-exponential model with random coefficients. A likelihood ratio test was ... View full abstract»

This paper introduces a real-time reliability prediction method for a dynamic system which suffers from a hidden degradation process. The hidden degradation process is firstly identified by use of particle filtering based on measurable outputs of the considered dynamic system. Then the system's reliability is predicted according to the model of the degradation path. We analyze the identification a... View full abstract»

The verification of the Mean Time To Repair (MTTR) is a problem of interest in many practical cases. As maintenance time can often be adequately described by a lognormal distribution, the problem leads us to research on statistical inference on the mean of the lognormal distribution. To achieve this purpose, we propose the Sequential Posterior Odd Test (SPOT) method for verification of the unknown... View full abstract»

Simultaneous discrimination among various parametric lifetime models is an important step in the parametric analysis of survival data. We consider a plot of the skewness versus the coefficient of variation for the purpose of discriminating among parametric survival models. We extend the method of Cox & Oakes from complete to censored data by developing an algorithm based on a competing risks m... View full abstract»

The failure probability of a product F(t), and the life time quantile t p are commonly used metrics in reliability applications. Confidence intervals are used to quantify the s-uncertainty of estimators of these two metrics. In practice, a set of pointwise confidence intervals for F(t), or the quantiles t p are often plotted on... View full abstract»

The integration of the products of diverse fields, including the human component, into complex systems has created major difficulties in the development of efficient mechanisms for analyzing system performance. One of the problems can be traced to the variety of terminologies used in describing performance across different fields. A designer or user is faced with vague terms that may be complement... View full abstract»

Shared segment protection (SSP), compared with shared path protection (SPP), and shared link protection (SLP), provides an optimal protection configuration due to the ability of maximizing spare capacity sharing, and reducing the restoration time in cases of a single link failure. This paper provides a thorough study on SSP under the GMPLS-based recovery framework, where an effective survivable ro... View full abstract»

We propose a reliability model for representing telecommunications networks that does not focus on topological information, but rather traffic path information. Mapping from traffic paths to physical elements and capacities enables the model to express simply how terrible performance degradations occur. Existing models, such as probability graph models, and probability-capacity graph models, do no... View full abstract»

A practical, important system performance index for analyzing real world systems is NP-hard multi-state two-terminal reliability. Contributions of this paper are 1) it presents a direct, correct decomposition method for solving NP-hard multi-state two-terminal reliability, and 2) it does not require a priori the multi-state minimal paths/cuts of the system. Because all the exact methods solve the ... View full abstract»

Current studies of the optimal design of multi-state series-parallel systems often focus on the problem of determining the optimal redundancy for each stage. However, this is only a partial optimization. There are two options to improve the system utility of a multi-state series-parallel system: 1) to provide redundancy at each stage, and 2) to improve the component state distribution, that is, ma... View full abstract»

To prevent wide-area disturbances, and enhance power system reliability, various forms of system protection scheme (SPS) have been designed and implemented by utilities. One of the main concerns in SPS deployment is to ensure that the system will fit with the reliability requirement specification in terms of dependability, and security. After major changes in system operating practices, or physica... View full abstract»

Multiple degradation paths arise when systems operate under uncontrolled, uncertain environmental conditions at customers' hands in the field. This paper presents a design stage method for assessing performance reliability of systems with competing time-variant responses due to components with uncertain degradation rates. Herein, system performance measures (e.g. selected responses) are related to... View full abstract»

A combined k-out-of-n:F(G) & consecutive kc -out-of-n :F(G) system fails (functions) iff at least k components fail (function), or at least fcc consecutive components fail (function). Explicit formulas are given for the lifetime distribution of these combined systems whenever the lifetimes of components are exchangeable, and have an absolutely continuous joint distribution. The lifetime... View full abstract»

Systems requiring very high levels of reliability, such as aircraft controls or spacecraft, often use redundancy to achieve their requirements. This paper provides highly efficient techniques for computing the reliability of redundant systems involving simple k-out-of-n arrangements, and those involving complex structures which may include imbedded k-out-of-n structures... View full abstract»

Systems which must be designed to achieve very low probabilities of failure often use redundancy to meet these requirements. However, redundant k-out-of-n:G systems which are subject to imperfect fault coverage have an optimum level of redundancy, n opt. That is to say, additional redundancy in excess of nopt will result in an increase, not a decrease, in the... View full abstract»

We discuss the interrelationship of two seemingly unrelated subjects: the theory of finite automata, and reliability theory, finite automata, more generally known as generalized transition graphs, are dasiaconvertedpsila to regular expressions by manipulating their pictorial representation, a directed graph, by elimination of its states one-by-one until two states are left, connected by an edge wh... View full abstract»

Analyses of residuals are used to assess a regression model, identify peculiar data points, and reveal the effect of other variables. Suitable residuals for accelerated life test data from step and varying stress tests have been needed. This article defines new, suitable residuals, and presents graphical and numerical analyses of them, which yield useful understanding of such data. Engineers can b... View full abstract»

A hybrid censoring scheme is a mixture of type-I and type-II censoring schemes. This article presents the statistical inferences on Weibull parameters when the data are type-II hybrid censored. The maximum likelihood estimators, and the approximate maximum likelihood estimators are developed for estimating the unknown parameters. Asymptotic distributions of the maximum likelihood estimators are us... View full abstract»

This paper presents results of an analysis of the sequential test (ST) procedures described in MIL-HDBK-781A, and IEC 61124, intended for checking the mean Time Between Failures (TBF) value under an exponential distribution of the TBF. The methodological basis of the calculations consists in discretization of the ST process through subdivision of the time axis in small segments. By this means, the... View full abstract»

This paper presents a new approach for detecting certain change-points, which may disturb the evaluation of reliability models with covariates, via a two-stage failure model, and stochastic time-lagged regression functions. The proposed model is developed with the Bayesian survival analysis method, and thus the problems for censored (or truncated) data in reliability tests can be resolved. In addi... View full abstract»