Search Results

Now showing 1 - 2 of 2
  • Article
    Nonparametric Tests for Comparing Reliabilities of Coherent Systems at Specific Mission Time
    (IEEE-Inst Electrical Electronics Engineers Inc, 2026) Xu, Xuan; Zhu, Xiaojun; Balakrishnan, Narayanaswamy; Ng, Hon Keung Tony
    Reliability analysis of coherent systems is critical for evaluating the performance of systems whose functionality depends on the reliability of their components. Traditional parametric methods for comparing reliabilities of coherent systems assume a specific probability distribution for component lifetimes, which may result in inaccurate results when these model assumptions are violated. This article introduces nonparametric procedures using system-level data with known signatures to compare the reliabilities of systems. The proposed methodology avoids parametric distributional assumptions for component lifetimes while relying on the standard assumption in signature-based reliability analysis. Specifically, a two-sample likelihood ratio test procedure is proposed to demonstrate a component or system with superior reliability. Monte Carlo simulations are performed to evaluate the performance of the proposed methods. Furthermore, we examine the effect of system structure on test power and determine favourable structures to enhance the power performance of the test. Practical examples are used to illustrate the proposed test procedures.
  • Article
    Citation - WoS: 3
    Citation - Scopus: 4
    Protection or Redundancy: Which is Better and When in Terms of Mean Time to Failure and Cost
    (Elsevier Sci Ltd, 2026) Eryilmaz, Serkan
    This article is about comparing the effectiveness of protection mechanism and redundancy methods in terms of mean time to failure and cost criteria. Under the protection mechanism, a component is assumed to have different failure rates when it is protected and nonprotected. The protection block is also subject to failure and has constant failure rate. Alternatively, a redundant component which has the same failure rate with the original component may be used to enhance the reliability. For single unit and series systems, necessary conditions on the failure rate of the component are obtained to have a relation between the mean time to failure values of the system under both protection and redundancy. The extension of the results to coherent systems is also discussed.