Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/8651
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Article A Covering Tour-Based Inventory Routing Framework for Humanitarian Logistics(Springer, 2026) Kanik, Zehra B.; Uzgören Kazanç, H. Cansın; Soysal, Mehmet; Coelho, Leandro C.; Kazanc, H. Cansin UzgorenIn post-disaster situations, swiftly delivering humanitarian assistance to victims amid chaos and uncertainty poses a significant challenge in practice. Furthermore, efficient distribution of restricted resources, effective inventory control, and optimal resource allocation remain imperative priorities for humanitarian organizations that strive to meet urgent needs under adverse conditions. This study proposes a two-echelon Covering Inventory Routing Problem (CIRP) that integrates the Inventory Routing Problem (IRP) and the Covering Tour Problem (CTP) to support decision-making in the distribution of medical kits in post-disaster humanitarian logistics. A scenario-based probabilistic Mixed-Integer Linear Programming (MILP) model is introduced to decrease costs while adequately addressing unpredictable demand. The applicability of the model was assessed through scenario analysis and a case study. In addition, a three-phase matheuristic algorithm is proposed to solve the CIRP. The results demonstrate that integrating IRP and CTP in a two-echelon structure improves both cost efficiency and the reach of aid delivery under uncertainty. The use of a static-dynamic inventory approach, together with coordinated routing, effectively minimizes emergency shipments and adapts to fluctuating demand, providing valuable support for decision-making in real-time humanitarian contexts. The three-phase matheuristic achieved cost reductions of over 70% relative to the model's incumbent solution within the first hour on large-scale instances, highlighting its practical use in accelerating decision-making amid post-disaster uncertainty.Article Refocus on Planning and Positive Refocusing Mediate the Relationship Between Cognitive Flexibility and Psychological Resilience(Springer, 2026) Mungan, Özlem; Torun Yazihan, NaksidilCognitive flexibility is one of the most important indicators of mental health and is a cognitive process at the heart of psychological resilience. The more cognitively flexible individuals are, the more likely they are to use adaptive emotion regulation strategies, which in turn increases their psychological resilience, according to the results of the current study. This study highlights the value of fostering cognitive flexibility and adaptive emotion regulation strategies to promote psychological resilience, and provides practical insights for practitioners. For future studies, training programmes designed to improve cognitive flexibility may have downstream benefits for emotion regulation and resilience-for example, cognitive behavioural therapy, rational-emotional therapy and mindfulness-based interventions, which are known to improve cognitive flexibility, may be particularly effective in promoting adaptive emotional responses.Conference Object The Generalized Finite Bivariate Biorthogonal M-Jacobi Polynomials(Springer, 2026) Çekim, Bayram; Özarslan, Mehmet Ali; Güldoğan Lekesiz, EsraArticle Improved Arithmetic Efficiency in TFHE Through Gate-Level Optimizations(Springer, 2025) Tasel, Faris Serdar; Saran, Ayse NurdanFully homomorphic encryption (FHE) enables computations to be performed directly on encrypted data without decryption, offering a promising solution for privacy-preserving applications, such as secure cloud computing, confidential machine learning, and encrypted analytics. However, one major drawback of FHE is the high computational cost of homomorphic operations, which slows down real-world implementations, making them impractical. This paper explores the implementation of arithmetic operations within the framework of Torus FHE (TFHE) and demonstrates the construction of gate-level optimization for fundamental operations such as addition, subtraction, negation, comparison, and multiplication on fixed-point numbers. Our work emphasizes optimizing arithmetic logic to reduce the number of bootstrapping operations, a critical factor in improving computational efficiency. Furthermore, we investigate the error rates associated with the proposed operations, providing valuable insight into their accuracy and practical applicability. This study contributes to developing more efficient and reliable arithmetic logic for privacy-preserving computations in FHE systems. The experimental results indicate that the proposed optimizations yield speedups of up to 2.27x for addition/subtraction, 3.55x for comparison, and 1.80x for multiplication operations.Editorial Introduction(Springer, 2008) Aydogan, N.Article Comparative Analysis of Impedance Matching Techniques in Wireless Power Transfer Efficiency: A Focus on Resonant, Adaptive, and Hybrid Approaches(Springer, 2025) Hatem, Sude; Kurt, ErolWireless power transfer (WPT) efficiency is highly dependent on impedance matching; however, comparative analyses of matching techniques under dy namic operating conditions remain limited. This study presents a systematic evaluation of three impedance matching approaches, namely resonant, adaptive, and hybrid, via theoretical modeling and numerical simulations. The results prove that adaptive impedance matching maintains stable efficiency (90.0% +/- 0.9%) in load variations (20-100 Omega ), coil misalignment (0<bold>degrees</bold>-30<bold>degrees</bold>), and transmission distances (0.1-1 cm), with minimal fluctuations. In contrast, resonant matching shows the best efficiency (i.e., 95%) under ideal conditions (10 MHz, 0<bold>degrees</bold> misalignment, 50 Omega load) but degrades rapidly to <50% under deviation conditions (e.g., 30 misalignment or 1 cm distance). The hybrid solution yields a balanced compromise that maintaining 85-92% efficiency in larger operating ranges. Quantitative metrics-the fluctuation rate (adaptive: 0.07 vs. resonant: 0.15) and stability index (adaptive: 102 vs. resonant: 20)-exhibit adaptive matching's superior dynamic performance. These find ings present practical advice on selecting impedance matching techniques in real WPTapplications, such as electric vehicle charging and medical implants, where stability under variability is paramount.Article Generalized Chebyshev Acceleration(Springer, 2025) Gokgoz, NurgulWe use generalized Chebyshev polynomials, associated with the root system \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$A_2$$\end{document}, to provide a new semi-iterative method for accelerating simple iterative methods for solving linear systems. We apply this semi-iterative method to the Jacobi method, and give an example. We also analyze the efficiency of our method with sparse matrices of large dimension. There are certain restrictions but the resulting acceleration is rather high.Article Citation - WoS: 51Citation - Scopus: 66Existence and Uniqueness of Solutions to Fractional Differential Equations in the Frame of Generalized Caputo Fractional Derivatives(Springer, 2018) Gambo, Y. Y.; Ameen, R.; Jarad, Fahd; Abdeljawad, T.The generalized Caputo fractional derivative is a name attributed to the Caputo version of the generalized fractional derivative introduced in Jarad et al. (J. Nonlinear Sci. Appl. 10:2607-2619, 2017). Depending on the value of. in the limiting case, the generality of the derivative is that it gives birth to two different fractional derivatives. However, the existence and uniqueness of solutions to fractional differential equations with generalized Caputo fractional derivatives have not been proven. In this paper, Cauchy problems for differential equations with the above derivative in the space of continuously differentiable functions are studied. Nonlinear Volterra type integral equations of the second kind corresponding to the Cauchy problem are presented. Using Banach fixed point theorem, the existence and uniqueness of solution to the considered Cauchy problem is proven based on the results obtained.Article Effects of Receiver Diversity on Bit Error Rate of Underwater Optical Wireless Communication Systems in Weak Oceanic Turbulence(Springer, 2025) Gokce, Muhsin Caner; Baykal, Yahya; Ata, YalcinThe receiver spatial diversity techniques are employed in underwater optical wireless communication (OWC) systems to mitigate oceanic turbulence, improving the bit error rate performance. In this paper, we consider an OWC system employing a binary phase-shift keying (BPSK) modulated Gaussian beam at the transmitter and employing receiver spatial diversity at the receiver. The techniques for receiver spatial diversity systems considered in the study are selection combining (SC), equal gain combining (EGC), and the maximum ratio combining (MRC). The bit error rate (BER) performance of the OWC system operating in weak oceanic turbulence is investigated by calculating the Gaussian beam's turbulence-induced scintillation index and the received optical intensity. It is found that the receiver spatial diversity techniques, especially EGC and MRC, are very effective for reducing the BER of an OWC system in weak oceanic turbulence. Furthermore, the BER performance of the underwater OWC system sees an improvement with an increase in the number of photodetectors or a decrease in the level of oceanic turbulence. Moreover, an improvement in the photodetector responsivity or a reduction in the system's noise factor contributes to achieving a favorable BER performance.Article Citation - WoS: 2Citation - Scopus: 1Interfacial Behavior and Diffusion Mechanisms of Bni-2 Brazing on Titanium Alloy: Experimental and Molecular Dynamics Insights(Springer, 2025) Goynuk, Tansu; Esen, Ziya; Karakaya, IshakContextJoining titanium alloys, particularly Ti-6Al-4V, is crucial in aerospace applications where reliable, high-performance joints are needed. Brazing offers an effective solution, enabling the joining of dissimilar materials without melting the base metals. However, optimizing the wetting and diffusion behavior of filler metals remains a challenge. This study investigates the high-temperature interaction between BNi-2 filler alloy and Ti-6Al-4V. Boron, the primary melting point depressant in BNi-2, was examined due to its small atomic size and interstitial diffusion mechanism. Elevated temperatures led to improved wetting, reflected by decreased contact angles. Both wetting angles and boron diffusion coefficients were obtained through molecular dynamics simulations and experimental measurements, showing reasonable correlation. These results provide valuable insight into interfacial mechanisms and support further optimization of brazing parameters.MethodsMolecular dynamics simulations were performed using LAMMPS to analyze the temperature-dependent wetting behavior of molten BNi-2 on Ti-6Al-4V and track atomic-scale diffusion. Initial atomic configurations were modeled and simulated under various conditions. Trajectory data were analyzed using OVITO for structural evolution. Boron diffusion was evaluated by calculating mean square displacement from LAMMPS outputs. These values were used to derive diffusion coefficients and activation energies. Parallel experiments were conducted to assess wetting angles and diffusion behavior, and simulation results were compared with experimental data. The consistency between both approaches highlights the reliability of the modeling framework in capturing essential mechanisms during the brazing process.