Search Results

Now showing 1 - 10 of 30
  • Article
    Citation - WoS: 5
    Component Importance in Coherent Systems With Exchangeable Components
    (Cambridge Univ Press, 2015) Eryilmaz, Serkan
    This paper is concerned with the Birnbaum importance measure of a component in a binary coherent system. A representation for the Birnbaum importance of a component is obtained when the system consists of exchangeable dependent components. The results are closely related to the concept of the signature of a coherent system. Some examples are presented to illustrate the results.
  • Article
    Citation - WoS: 6
    Citation - Scopus: 6
    Reliability Analysis of Systems With Components Having Two Dependent Subcomponents
    (Taylor & Francis inc, 2017) Eryilmaz, Serkan
    In this article, a system that consists of n independent components each having two dependent subcomponents (A(i), B-i), i = 1, ... ,n is considered. The system is assumed to compose of components that have two correlated subcomponents (A(i), B-i), and functions iff both systems of subcomponents A(1),A(2), ... ,A(n) and B-1, B-2, ... , B-n work under certain structural rules. The expressions for reiiabiiity and mean time to failure of such systems are obtained. A sufficient condition to compare two systems of bivariate components in terms of stochastic ordering is also ordering presented.
  • Article
    Citation - WoS: 27
    Citation - Scopus: 31
    Generalized Extreme Shock Models and Their Applications
    (Taylor & Francis inc, 2020) Bozbulut, Ali Riza; Eryilmaz, Serkan
    In the classical extreme shock model, the system fails due to a single catastrophic shock. In this paper, by assuming different arrival patterns of the shocks, two new types of extreme shock models are introduced. In these models, m possible sources may exert shocks on the system. Both models reduce to the classical extreme shock model when m = 1. Assuming phase-type distribution for times between successive shocks, we obtain survival functions and mean time to failure values of the system under new models. Two different optimization problems are also considered to determine the optimal number of sources.
  • Article
    Citation - WoS: 12
    Citation - Scopus: 15
    Dynamic Reliability Evaluation of Consecutive-K System
    (Taylor & Francis inc, 2011) Eryilmaz, Serkan; Kan, Cihangir
    A consecutive k-within-m-out-of-n:F system consists of n linearly ordered components and fails if and only if there are m consecutive components which include among them at least k failed components. This system model generalizes both consecutive k-out-of-n:F and k-out-of-n:F systems. In this article, we study the dynamic reliability properties of consecutive k-within-m-out-of-n:F system consisting of exchangeable dependent components. We also obtain some stochastic ordering results and use them to get simple approximation formulae for the survival function and mean time to failure of this system.
  • Article
    A Class of Shock Models for a System That Is Equipped With a Protection Block With an Application to Wind Turbine Reliability
    (Wiley, 2025) Eryilmaz, Serkan
    This paper studies a class of shock models for a system that is equipped with a protection block that has its own failure rate. Under the considered class, the system exposed to shocks at random times is protected by the protection block, and the probability of the shock damaging the system varies depending on whether the protection block operates or not. The system failure criteria is defined based on the pattern of the critical/damaging shocks. Exact expressions for the reliability and mean time to failure of the system are obtained, and detailed computations are presented for the run shock model, which is included in the class. The application of the extreme shock model, which is included in the relevant class, to wind turbine reliability is also discussed.
  • Article
    Citation - WoS: 17
    Citation - Scopus: 16
    A Study on Reliability of Coherent Systems Equipped With a Cold Standby Component
    (Springer Heidelberg, 2014) Eryilmaz, Serkan
    In this paper, we investigate the effect of a single cold standby component on the performance of a coherent system. In particular, we focus on coherent systems which may fail at the time of the first component failure in the system. We obtain signature based expressions for the survival function and mean time to failure of the coherent systems satisfying the abovementioned property.
  • Article
    Citation - WoS: 6
    Citation - Scopus: 7
    Modeling Systems With Two Dependent Components Under Bivariate Shock Models
    (Taylor & Francis inc, 2019) Eryilmaz, Serkan
    Series and parallel systems consisting of two dependent components are studied under bivariate shock models. The random variables N-1 and N-2 that represent respectively the number of shocks until failure of component 1 and component 2 are assumed to be dependent and phase-type. The times between successive shocks are assumed to follow a continuous phase-type distribution, and survival functions and mean time to failure values of series and parallel systems are obtained in matrix forms. An upper bound for the joint survival function of the components is also provided under the particular case when the times between shocks follow exponential distribution.
  • Article
    Citation - WoS: 6
    Citation - Scopus: 6
    Dynamic Reliability and Performance Evaluation of Multi-State Systems With Two Components
    (Hacettepe Univ, Fac Sci, 2011) Eryilmaz, Serkan; Industrial Engineering
    In this paper we study multi-state systems consisting of two components when the number of system states and the number of states of each component are the same, i.e. the systems under consideration are homogeneous multi-state systems. In particular we evaluate multi-state series and cold standby systems assuming that the degradation in their components follow a Markov process. The behaviour of systems with respect to degradation rates is also investigated in terms of stochastic ordering.
  • Editorial
    Discussion of Signature-Based Models of Preventive Maintenance
    (Wiley, 2023) Eryilmaz, Serkan
    [No Abstract Available]
  • Article
    Citation - WoS: 12
    Citation - Scopus: 14
    The Markov Discrete Time Δ-Shock Reliability Model and a Waiting Time Problem
    (Wiley, 2022) Chadjiconstantinidis, Stathis; Eryilmaz, Serkan
    delta-shock model is one of the widely studied shock models in reliability theory and applied probability. In this model, the system fails due to the arrivals of two consecutive shocks which are too close to each other. That is, the system breaks down when the time between two successive shocks falls below a fixed threshold delta. In the literature, the delta-shock model has been mostly studied by assuming that the time between shocks have continuous distribution. In the present paper, the discrete time version of the model is considered. In particular, a proper waiting time random variable is defined based on a sequence of two-state Markov dependent binary trials and the problem of finding the distribution of the system's lifetime is linked with the distribution of the waiting time random variable, and we study the joint as well as the marginal distributions of the lifetime, the number of shocks and the number of failures associated with these binary trials.