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Permanent URI for this collectionhttps://hdl.handle.net/20.500.14411/18
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Article Reliability Evaluation of a System Protected by Blocks(Oxford Univ Press, 2026-04-30) Eryilmaz, SerkanWe model the reliability of a system with a main component and two auxiliary components for protection, one active, the other on cold standby. The main component performs the system function. The auxiliary components are called protection blocks. The failure rate of the main component depends on whether it is protected or not. The blocks have their own constant failure rate, that is, their lifetimes are exponentially distributed. The reliability of such a system is obtained and the properties of its failure rate are investigated. A necessary condition is obtained to compare the cost-effectiveness of single and two-block protection. Likewise, we obtain necessary conditions for comparing the effectiveness of different three-component designs under the mean time to failure criterion. In this way, the work provides decision support for the designers of systems protected by blocks.Article Analogies between Engineering and Biological Systems from Reliability Engineering Point of View: Some Thoughts in the New AI Era(Taylor & Francis Inc, 2026-05-14) Eryilmaz, SerkanThis article aims to establish an analogy between engineering systems and biological systems by focusing on some reliability and statistical models and concepts. Since reliability is by definition concerned with the future health and behavior of a system, reliability models are also considered to have potential applications for the human organism. In fact, this potential already exists through the overlap and intersection between reliability theory and survival analysis. In this context, in this article, some reliability models and concepts that have not been discussed before will be adapted to a human organism, taking into account today's data-driven processes and artificial intelligence-based developments.Article A Note on Hazard Rates of Systems Protected by a Block(Springer Heidelberg, 2026-04-29) Eryilmaz, SerkanThis paper is concerned with the investigation of the properties of the hazard rate of the system protected by a block. By examining the characteristics of the hazard rate of the system supported by a protection block, a comparison is made with the redundancy method, according to the hazard rate. It is shown that the lifetime of the system supported by the protection block is larger than the lifetime of the system equipped with redundant system asymptotically in the hazard rate order. The extension of the results to a system with multiple components is also discussed for a consecutive k-out-of-n system.Article A Note on Hazard Rates of Systems Protected by a Block(Metrika, 2026-04-29) Eryilmaz, SerkanThis paper is concerned with the investigation of the properties of the hazard rate of the system protected by a block. By examining the characteristics of the hazard rate of the system supported by a protection block, a comparison is made with the redundancy method, according to the hazard rate. It is shown that the lifetime of the system supported by the protection block is larger than the lifetime of the system equipped with redundant system asymptotically in the hazard rate order. The extension of the results to a system with multiple components is also discussed for a consecutive k-out-of-n system.Article Reliability Evaluation of a System Protected by Blocks(IMA Journal of Management Mathematics, 2026-04-30) Eryilmaz, SerkanWe model the reliability of a system with a main component and two auxiliary components for protection, one active, the other on cold standby. The main component performs the system function. The auxiliary components are called protection blocks. The failure rate of the main component depends on whether it is protected or not. The blocks have their own constant failure rate, that is, their lifetimes are exponentially distributed. The reliability of such a system is obtained and the properties of its failure rate are investigated. A necessary condition is obtained to compare the cost-e¤ectiveness of single and two-block protection. Likewise, we obtain necessary conditions for comparing the e¤ectiveness of di¤erent three-component designs under the mean time to failure criterion. In this way, the work provides decision support for the designers of systems protected by blocks.Article Robust Inference for Step-Stress Experiments under Interval-Censoring(Springer, 2026-04-20) Balakrishnan, Narayanaswamy; Jaenada, María; Pardo, LeandroMany moderns products have a long life before failure. Reliability analyses for such highly reliable devices therefore present a practical challenge as obtaining sufficient failure information to adequately assess lifetime behavior will require extended experimental duration. As an alternative, accelerated life testing (ALT) is commonly used to shorten the time to failure of units under test, with the results subsequently extrapolated to normal operating conditions. This paper provides a comprehensive review of robust inferential methods based on density power divergence for analyzing step-stress ALT data. Point estimates and approximate confidence intervals for model parameters, along with robust estimates of some important lifetime characteristics are developed for general lifetime distributions. Subsequently, explicit expressions are derived for four most prominent parametric lifetime distributions: exponential, Weibull, gamma, and lognormal. A semi-parametric approach based on the proportional hazards model and a competing risks scenario are also discussed as extensions of the proposed model. Throughout the manuscript, several open problems are highlighted, along with significant gaps in the literature, to motivate readers and also to promote further research in this important research area. Moreover, to illustrate the importance of step-stress ALTs and the practical utility of robust estimators, we also present some real data sets used in the literature and analyze one of them using robust methods. By analyzing real data, we demonstrate the stability of the Minimum Density Power Divergence Estimator (MDPDE) for different values of the tuning parameter in the presence of outliers. We also analyze the implications of distributional assumptions on parameter estimation. Confidence intervals, including transformed intervals, are examined, with transformed intervals resulting in confidence levels close to nominal level and also provide better interpretability. Our results highlight the importance of robust estimation techniques in the presence of data contamination and also in a careful selection of parametric models for modeling the lifetime data, as these choices significantly influence predictions of lifetime characteristics under normal operating conditions.Article Adaptation of the Food Waste Avoidance Motivation Scale into Turkish: A Validity and Reliability Study(Marmara Univ, Inst Health Sciences, 2026-03-27) Inan, Cansu Memiç; Cetiner, Özlem; Sarahman-Kahraman, Ceren; Soylu, MeltemObjective: We conducted this research to assess the psychometric properties of the Turkish version of the Food Waste Avoidance Motivation (MAFW) scale, specifically focusing on its use with adults. Methods: Between January and May 2025, data for this research were obtained via in-person interviews conducted with adults who are residents of Nigde, Turkey. The validity of the MAFW scale was examined by employing Confirmatory Factor Analysis (CFA). The internal reliability of the instrument was determined through consistency analysis; consequently, the Cronbach's alpha coefficient was derived. Results: The study's sample population comprised 268 adult subjects, with a mean age of 29.0 +/- 10.5 years. With an overall Cronbach's alpha of 0.88, the MAFW scale demonstrated strong internal consistency. The reliability coefficients for its individual subscales were observed to fall within the range of 0.82 to 0.96. The four-factor structure of the MAFW scale (environmental motivation, social motivation, financial motivation, and moral motivation) was confirmed through CFA, and the fit indices indicated a good model fit (chi & sup2;/sd=2.88; RMSEA=0.084; GFI=0.95; AGFI=0.94; CFI=0.92; TLI=0.91; SRMR=0.04). According to the convergent validity analysis, significant correlations were observed between the MAFW scale score and the Plate Clearing Tendency Scale and Household Food Security Survey Module- Short Form. Convergent validity analyses showed statistically significant but weak correlations between the MAFW scale score and both the Plate Clearing Tendency Scale and the Household Food Security Survey Module-Short Form Conclusion: Our findings indicate that the Turkish adaptation of the MAFW scale can be effectively utilized as a valid and reliable tool for measuring adult motivation to avoid food waste. The MAFW scale presents a valuable resource for subsequent studies aiming to gauge individuals' knowledge, opinions, and actions concerning food wastage.Article Citation - WoS: 2Citation - Scopus: 1The Evaluation of System Reliability Under Dependent Shock Magnitudes(Springer, 2026-03) Eryilmaz, SerkanThis paper studies shock models by assuming a certain kind of dependence among shock magnitudes. In particular, discrete time extreme and run shock models are investigated when the shock magnitudes follow discrete autoregressive process of order 1. Exact expressions are obtained for the reliability functions and mean time to failure values under both models. The method for deriving the reliability characteristics is based on the use of probability generating functions. Numerical results are presented when the shocks arrive according to a Binomial process.Article Circular One/Two/Three-Dimensional Consecutive k-Type Systems(Springer, 2026-03) Yi, He; Balakrishnan, Narayanaswamy; Li, XiangIn this paper, several circular one/two/three-dimensional consecutive k-type systems are studied, including circular consecutive-k-out-of-n: F systems, circular l-consecutivek-out-of-n: F systems without/with overlapping, circular connected-(k(1), k(2))-outof-(n(1), n(2)): F systems, circular l-connected-(k(1), k(2))-out-of-(n(1), n(2)): F systems without/ with overlapping, circular connected-(k(1), k(2), k(3))-out-of-(n(1), n(2), n(3)): F systems, and circular l-connected-(k(1), k(2), k(3))-out-of-(n(1), n(2), n(3)): F systems without/with overlapping. Reliability functions of these systems are studied using finite Markov chain imbedding approach (FMCIA). Some illustrative examples are provided, and possible applications and generalizations of the established results are also mentioned.Article A General Type of Linear Consecutive-K Systems(Springer, 2026-02-17) Yi, He; Balakrishnan, Narayanaswamy; Li, XiangIn this paper, some well-known consecutive k-type systems, including linear consecutive-k-out-of-n: F systems and linear l-consecutive-k-out-of-n: F systems without/with overlapping, are generalized by using more general failure patterns. Finite Markov chain imbedding approach (FMCIA) is applied in a new way for evaluating reliabilities of these generalized new systems. Some illustrative examples are provided for demonstrating the theoretical results established here and also for showing the efficiency of the computational process. Finally, some possible applications and generalizations are mentioned.