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Permanent URI for this collectionhttps://hdl.handle.net/20.500.14411/18
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Article Generalized Chi-Squared Based Goodness-of-Fit Tests under Progressive Type-II Censoring for Exponential and Weibull Distributions(Taylor & Francis Inc, 2026) Schmiedt, Anja B.; Balakrishnan, Narayanaswamy; Cramer, ErhardWe propose new goodness-of-fit tests for exponentiality based on progressively Type-II censored data. These tests utilize scale-invariant statistics obtained from the Mahalanobis norm of normalized order statistics, leading to three test statistics, corresponding to L-2(-), L-1(-), and L-infinity-norms of centered uniform spacings. Exact and asymptotic distributions of these statistics are presented. A power study evaluates the proposed tests against existing benchmarks across various alternative distributions and censoring plans, demonstrating superior performance in cases with small and moderate sample sizes. Furthermore, we extend the methodology to approximate goodness-of-fit tests for Weibull distributions via power transformation, ensuring robustness w.r.t. the approximated significance level under unknown shape parameters. An illustrative data example confirms the practical applicability of our tests. Our findings highlight the potential for further extending goodness-of-fit tests under progressive Type-II censoring to other null distributions.Article Blockchain Integration for Circular Economy Adoption in Steel Construction(Emerald Group Publishing Ltd, 2026) Bilgin, Gozde; Birgonul, M. Talat; Akcay, Emre Caner; Dikmen, Irem; Demir, BerkanPurposeThe circular economy (CE) is an economic model aimed at minimizing waste and optimizing resource use by extending lifecycles through recycling, reuse, and other strategies. This shift from the traditional linear model (take-make-dispose) is crucial for a more sustainable and resilient built environment. Given its environmental impact, the steel construction industry holds significant importance in driving sustainability and CE efforts. This study aims to explore the potential of a blockchain(BC)-based framework to overcome barriers hindering the adoption of CE principles within the industrial steel construction sector, thereby promoting sustainability and circularity in the built environment.Design/methodology/approachA conceptual BC framework is proposed to enable effective recording, storing, and sharing of process-related data among stakeholders throughout the lifecycle of construction materials. The framework's validity is assessed through a focus group study conducted at a steel construction company, involving expert evaluations.FindingsExpert evaluations indicate that the BC-based framework can significantly enhance CE adoption by improving information flow, raising awareness, and fostering collaboration among ecosystem participants.Originality/valueThe study introduces an innovative application of BC technology tailored for the steel construction sector to address specific CE barriers, offering a novel approach that facilitates digital and sustainability transitions.Article Real Interest Rate Parity in Latin American Countries: Evidence from New Panel Unit Root Tests(Wiley, 2026) Omay, Tolga; Abioglu, Vasif; Hasanli, MubarizIn this study, we test the empirical validity of the real interest rate parity hypothesis for 15 Latin American countries over the period 2005-2023. To this end, we employ a battery of panel unit root tests to examine stochastic properties of the real interest rate differentials (RIDs) of the countries under consideration. The panel unit root tests that allow for both the cross-sectional dependence and the nonlinearities in the adjustment process do not reject the null of unit root for the most of these countries, suggesting that the real interest rate parity hypothesis does not hold for these countries. On the other hand, the panel unit root test that allows for smooth structural changes produces results consistent with the real interest rate parity hypothesis for 12 out of 15 Latin American countries. These findings imply that various shocks, including political, economic, and financial upheavals, can cause significant structural shifts in the RIDs of Latin American countries.Article A Decomposition of the Limit Q-Bernstein Type Operators Via a Universal Factor(Springer Basel AG, 2026) Ostrovska, Sofiya; Pirimoglu, Lutfi Atahan; Turan, MehmetThe focus of this work is on the properties of the unifying operator Uq\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$U_q$$\end{document} on C[0, 1], which serves as a universal left factor in a decomposition of the limit q-Bernstein type operators, L infinity,q\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$L_{\infty ,q}$$\end{document}. More precisely, the factorization L infinity,q=Uq degrees TL\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$L_{\infty ,q}= U_q\circ T_L$$\end{document}, where TL\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$T_L$$\end{document} is a linear operator on C[0, 1] depending on L, holds. It is shown that this factorization facilitates the derivation of new results and/or the simplification of proofs for the known ones.Article Mild Solutions for Neutral Conformable Fractional Order Functional Evolution Equations Using Meir-Keeler Type Fixed Point Theorem(University Politehnica Bucharest, Sci Bull, 2025) Berrighi, Fatma; Medjadj, Imene; Karapinar, ErdalOur mission is to demonstrate the existence, uniqueness, attractiveness, and controllability of mild solutions to neutral conformable fractional-order functional evolution equations, specifically of order between 1 and 2. These intriguing equations encompass finite delay, all while adhering to local conditions within a separable Banach space. By invoking Meir-Keeler's fixed-point Theorem and enhancing it with measures of noncompactness, we establish the existence of these solutions. To highlight the potency of our approach, we present a captivating example.Article How TikTok Works for Digital Diplomacy During Conflict/War Times: The Cases of Russia-Ukraine and Israel-Gaza Conflicts(Routledge Journals, Taylor & Francis Ltd, 2025) Artan Ozoran, Beris; Seyidov, Ilgar; Erdogan, BurakDuring times of conflict and war, public diplomacy undergoes a significant transformation, with strategic communication shifting from traditional channels to highly visual and participatory digital platforms. Among these, TikTok has emerged as a key arena for states to shape perceptions and mobilize international audiences. This study explores how TikTok is utilized as a tool of digital diplomacy by examining the official accounts of Ukraine and Israel during the Russia - Ukraine war and the Israel - Gaza conflict. Drawing on Strategic Narrative Theory (SNT), the analysis categorizes state-produced content into system, identity, and issue narratives and investigates how these narrative types effect audience engagement on the platform. By integrating narrative analysis with quantitative engagement metrics, this research not only extends SNT into the context of short-form video platforms but also contributes to the growing literature on digital diplomacy in wartime contexts.Article Clinicopathological Predictors of Central Lymph Node Metastasis in Clinically Node-Negative Papillary Thyroid Carcinoma: A Retrospective Cohort Analysis(Springer, 2025) Sakiz, Davut; Calapkulu, Murat; Sencar, Muhammed Erkam; Unsal, Ilknur Ozturk; Kartal, Mehmet Zabit; Ucan, Bekir; Cakal, ErmanPurposeThis retrospective cohort study aimed to identify clinicopathological predictors of central lymph node metastasis (CLNM) in patients with papillary thyroid carcinoma (PTC).MethodsA total of 503 patients with PTC who underwent thyroidectomy with central lymph node dissection were included. Preoperative clinical data, ultrasonographic features, and postoperative histopathological characteristics were analyzed.ResultsCLNM was detected in 209 (41.55%) patients. Male sex (odds ratio [OR] = 3.12, 95% CI: 1.82-5.35), irregular nodule borders (OR = 2.02, 95% CI: 1.25-3.26) and higher risk categories in the American Thyroid Association (ATA) ultrasonographic pattern stratification system (OR = 13.312, 95% CI: 8.623-20.551) were identified as independent preoperative predictors of CLNM. A simplified model incorporating only the ATA ultrasonographic pattern stratification system and male sex achieved 83.5% accuracy in predicting CLNM. Histopathological evaluation revealed lymphovascular invasion (OR = 4.61, 95% CI: 2.81-7.55), extrathyroidal extension (OR = 2.41, 95% CI: 1.52-3.83), and multifocality (OR = 1.58, 95% CI: 1.04-2.40) as independent predictors of CLNM, while lymphocytic thyroiditis (OR = 0.59, 95% CI: 0.39-0.89) was a protective factor.ConclusionThis study establishes that ATA ultrasonographic suspicion patterns combined with the male sex provide an accurate and simplified model for preoperative CLNM prediction in PTC, outperforming complex nomograms. Key independent predictors included male sex, irregular nodule margins, ATA high-risk patterns, lymphovascular invasion, extrathyroidal extension, and multifocality, while lymphocytic thyroiditis was protective. According to the current study, risk assessment and personalized management should favor a holistic approach, rather than focusing solely on individual risk factors.Conference Object GC Contents of the Genes May Imply Associations with Coronary Artery Disease, Autism, Obesity, and Type 2 Diabetes(Wiley, 2025) Adiguzel, Y.; Yekeler, S. E.; Mohamed, A. A.; Turker, D.; Ozcan, L. E.; Sert, G.; Acet, K.Article Citation - WoS: 1Citation - Scopus: 1PMMA-Based Electrospun Composite Fibers for Dye Adsorption From Water(Sage Publications Ltd, 2026) Cakar, Ilknur; Yesil, Sertan; Bayram, GoknurPoly (methyl methacrylate) (PMMA) and PMMA/poly (ethylene glycol) (PEG)-based composite fibers were produced using electrospinning technique with two different additives; halloysite nanotubes (HNTs) and boron phosphate (BPO4). The effect of the additives on the morphology, wettability and dye adsorption properties of electrospun fibers were investigated by Scanning Electron Microscopy (SEM), water contact angle measurement and UV-VIS spectrophotometry. The results of SEM analysis indicated that addition of PEG resulted in thinner average fiber diameter and beaded structure. Additionally, it was also observed that incorporating both HNT and BPO4 to the PMMA solution caused increased fiber diameter which might be due to increased solution viscosity. For PMMA fibers containing 3 wt% HNT, the highest average diameter and water contact angle were measured as 2204 +/- 302 nm and 110.29 +/- 3.9 degrees, respectively. The produced fibers were tested for the capability to adsorb methylene blue (MB) and methyl orange (MO) from aqueous solutions. Dye adsorption capacity of the samples increased by addition of HNT and BPO4. According to adsorption capacity results, PMMA/PEG/BPO4 composite sample containing 5 wt% BPO4, with an adsorption capacity of 0.76 mg/g, was determined as adsorbent for kinetic and isotherm studies. The adsorption kinetics were well described by the pseudo-second-order model, and equilibrium data were correlated with the Langmuir model.Article Citation - WoS: 2Citation - Scopus: 2Physics-Informed Neural Network for Nonlinear Bending Analysis of Nano-Beams: A Systematic Hyperparameter Optimization(MDPI, 2025) Esfahani, Saba Sadat Mirsadeghi; Fallah, Ali; Aghdam, Mohammad Mohammadi; Mohammadi Aghdam, Mohammad; Mirsadeghi Esfahani, Saba SadatThis paper investigates the nonlinear bending analysis of nano-beams using the physics-informed neural network (PINN) method. The nonlinear governing equations for the bending of size-dependent nano-beams are derived from Hamilton's principle, incorporating nonlocal strain gradient theory, and based on Euler-Bernoulli beam theory. In the PINN method, the solution is approximated by a deep neural network, with network parameters determined by minimizing a loss function that consists of the governing equation and boundary conditions. Despite numerous reports demonstrating the applicability of the PINN method for solving various engineering problems, tuning the network hyperparameters remains challenging. In this study, a systematic approach is employed to fine-tune the hyperparameters using hyperparameter optimization (HPO) via Gaussian process-based Bayesian optimization. Comparison of the PINN results with available reference solutions shows that the PINN, with the optimized parameters, produces results with high accuracy. Finally, the impacts of boundary conditions, different loads, and the influence of nonlocal strain gradient parameters on the bending behavior of nano-beams are investigated.