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Article Robust Divergence-Based Tests of Hypotheses for Simple Step-Stress Accelerated Life-Testing Under Gamma Lifetime Distributions(Elsevier B.V., 2026) Balakrishnan, N.; Jaenada, M.; Pardo, L.Many modern devices are highly reliable, with long lifetimes before their failure. Conducting reliability tests under actual use conditions may require therefore impractically long experimental times to gather sufficient data for developing accurate inference. To address this, Accelerated Life Tests (ALTs) are often used in industrial experiments to induce product degradation and eventual failure more quickly by increasing certain environmental stress factors. Data collected under such increased stress conditions are analyzed, and results are then extrapolated to normal operating conditions. These tests typically involve a small number of devices and so pose significant challenges, such as interval-censoring. As a result, the outcomes are particularly sensitive to outliers in the data. Additionally, a comprehensive analysis requires more than just point estimation; inferential methods such as confidence intervals and hypothesis testing are essential to fully assess the reliability behaviour of the product. This paper presents robust statistical methods based on minimum divergence estimators for analyzing ALT data of highly reliable devices under step-stress conditions and Gamma lifetime distributions. Robust test statistics generalizing the Rao test and divergence-based tests for testing linear null hypothesis are then developed. These hypotheses include in particular tests for the significance of the identified stress factors and for the validity of the assumption of exponential lifetimes. © 2026Article Citation - Scopus: 6A Generalization of the Meir–keeler Type Contraction(Elsevier B.V., 2012) Chi,K.P.; Karapinar,E.; Thanh,T.D.In this paper, we prove a fixed point theorem which has applications on maps called T-contractions which include a class that satisfies the Meir–Keeler type contractive condition. We also present an example that illustrates that T-contractions are a natural extension of the Meir–Keeler type contraction. © 2012Article The Effect of Two Different Types of Daily Disposable Monofocal Contact Lenses on Ocular Wavefront Aberrations(Elsevier B.V., 2025) Yakar, K.Background: To compare the effect of two daily disposable soft contact lenses on ocular wavefront aberrations. Methods: This study included 34 eyes from 17 patients aged 18 to 40 years (mean age: 27.12±8.3 years) with identical myopic refractive errors in both eyes without astigmatism and requesting contact lens use. Initially, wavefront aberrations; total, tilt, high, total coma, total trefoil, total 4.foil, sphere, high astigmatism, RMS (3 mm/5 mm) were measured using Nidek OPD Scan II aberrometer/topograph in both eyes without contact lenses. Acuvue Oasys with HydraLuxe 1-Day (senofilcon A) daily disposable contact lenses were applied to the right eye, while Precision 1 (verofilcon A) daily disposable contact lenses were applied to the left eye based on refractive errors. Wavefront aberration measurements were repeated 60 min later with contact lenses, and aberrations were compared to baseline and fellow eyes' measurements. The magnitudes of aberration changes after contact lens application were analyzed. Results: Both types of daily disposable contact lenses reduced total wavefront aberrations. Acuvue Oasys with HydraLuxe 1-Day contact lenses showed a significant increase in total trefoil aberration (p = 0.048). Precision 1 contact lenses showed a significant increase (p = 0.034) only in total tilt aberrations compared to baseline. No significant differences were found between the lenses regarding changes in all wavefront aberrations. Conclusion: Both daily disposable lenses effectively reduced total wavefront aberrations, though they increased certain subtypes of high-order aberrations in young adult myopes. © 2025 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC license. http://creativecommons.org/licenses/by-nc/4.0/
