Browsing by Author "Bulanik, Irem"

Now showing 1 - 3 of 3

Citation - WoS: 2
Citation - Scopus: 1
Age replacement policies for discrete and continuous heterogeneous k-out-of-n systems
(Springer, 2024) Eryilmaz, Serkan; Bulanik, Irem
This paper studies age replacement policy for the k-out-of-n system that consists of independent but nonidentical components. Both continuously and discretely distributed components' lifetimes are considered. The failed components are replaced by new components and non-failed components are rejuvenated. Because the components are non-identical, the acquisition and rejuvenation costs of the components are chosen differently. The policy and the associated optimization problem are presented for general k and n, and 2-out-of-3 systems are studied in detail. The findings of the present paper extend the results in the literature from parallel systems to k-out-of-n systems.
Citation - WoS: 7
Citation - Scopus: 9
Computing Reliability Indices of a Wind Power System Via Markov Chain Modelling of Wind Speed
(Sage Publications Ltd, 2024) Eryilmaz, Serkan; Bulanik, Irem; Devrim, Yilser
Statistical modelling of wind speed is of great importance in the evaluation of wind farm performance and power production. Various models have been proposed in the literature depending on the corresponding time scale. For hourly observed wind speed data, the dependence among successive wind speed values is inevitable. Such a dependence has been well modelled by Markov chains. In this paper, the use of Markov chains for modelling wind speed data is discussed in the context of the previously proposed likelihood ratio test. The main steps for Markov chain based modelling methodology of wind speed are presented and the limiting distribution of the Markov chain is utilized to compute wind speed probabilities. The computational formulas for reliability indices of a wind farm consisting of a specified number of wind turbines are presented through the limiting distribution of a Markov chain. A case study that is based on real data set is also presented.
Citation - WoS: 32
Citation - Scopus: 41
Reliability Based Modeling of Hybrid Solar/Wind Power System for Long Term Performance Assessment
(Elsevier Sci Ltd, 2021) Eryilmaz, Serkan; Bulanik, Irem; Devrim, Yilser
This paper is concerned with reliability based long-term performance assessment of hybrid solar/wind power system. In particular, an analytical expression is obtained for the theoretical distribution of the power output of the hybrid system by taking into account the reliability values of renewable energy components. An expression for the expected energy not supplied (EENS) is also derived and used to compute the energy index of reliability (EIR) that is directly related to EENS. Because the derived expressions involve reliability values which are related to mechanical states of the renewable energy components, the results enable us to evaluate properly the performance of the hybrid system. A numerical example is included to illustrate the results.