Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/395
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Article Citation - WoS: 1Two-Local Modifications of Sachdev-Ye Model With Quantum Chaos(American Physical Society, 2026-01-27) Hanada, M.; Van Leuven, S.; Oktay, O.; Tezuka, M.The Sachdev-Ye-Kitaev (SYK) model may provide us with a good starting point for the experimental study of quantum chaos and holography in the laboratory. Still, the four-local interaction of fermions makes quantum simulation challenging, and it would be good to search for simpler models that keep the essence. In this paper, we argue that the four-local interaction may not be important by introducing a few models that have two-local interactions. The first model is a generalization of the spin-SYK model, which is obtained by replacing the spin variables with SU(d) generators. Simulations of this class of models might be straightforward on qudit-based quantum devices. We study the case of d=3,4,5,6 numerically and observe quantum chaos already for two-local interactions in a wide energy range. We also introduce modifications of spin-SYK and SYK models that have similar structures as the SU(d) model (e.g., H=∑p,qJpqχpχp+1χqχq+1 instead of the original SYK Hamiltonian H=∑p,q,r,sJpqrsχpχqχrχs), which shows strongly chaotic features although the interaction is essentially two-local. These models may be a good starting point for the quantum simulation of the original SYK model. ©2026 American Physical Society.Article Enhancing Mode Transition Dynamics in Non-Inverting Buck-Boost Inverters for PV Systems(Institute of Electrical and Electronics Engineers Inc., 2026) Keskinkilic, E.; Tekgun, B.Quasi-single-stage inverters (QSSIs) are notable for their simple structure and bidirectional operation capability in applications such as photovoltaic (PV) systems. Among these QSSI, the non-inverting buck-boost inverter (NIBBI) or four-switch buck-boost inverter (FSBBI) is often preferred due to its ability to perform both step-down and step-up operations. However, when traditional control is used, achieving a smooth transition and efficient conversion becomes challenging as the output voltage approaches the input voltage. The pulse width ratio limitations and non-idealities of active and passive components are the cause of this. In this paper, a comparative analysis of the mode transition techniques in FSBBI is presented using methods available for DC/DC converters. System efficiency and output voltage signal quality are selected as performance metrics. A 2-kW FSBBI is installed and controlled using single, two, modified two, three, and four-mode techniques. Simulation and experimental studies were conducted to validate the results. Based on these studies, the four-mode control technique was observed to be the most effective in eliminating dead zone effects, reducing total harmonic distortion (THD), and achieving the highest system efficiency in a PV system where a battery powers the AC load. Experimental results indicate that the four-mode modulation attained an efficiency of 95.49% with a THD of 2.97%. © 1986-2012 IEEE.Article Resilience and Market Diversification in Sustainable Tourism: Evidence from International Arrivals to Türkiye (2012-2025)(Emerald Group Publishing Ltd, 2026-02-02) Atay, Mehmet Tarik; Ciuffreda, Raffaela; Coskun, Safa BozkurtPurposeThis study analyzes the possible connections between resilience and market diversification of inbound tourism to T & uuml;rkiye from 2012 to 2025. The aim is to assess the reaction of international arrivals to global fluctuations, such as the COVID-19 pandemic era, and to examine the structural linkage to primary source markets within the concept of sustainable tourism management.Design/methodology/approachThe research uses annual country-specific data related to international arrivals. We used time-series analysis to uncover long-term behaviors and the consequences of crises. The research also used Shannon entropy and the Herfindahl-Hirschman Index to look at market concentration and diversity. A comparative analysis of the primary source countries indicates variations in recovery trajectories and resilience in the concept of sustainable tourism management.FindingsThe results show that T & uuml;rkiye's inbound tourism grew steadily until 2019, decreased severely during the pandemic and then bounced back strongly from 2022 to 2024. Market diversity has improved over time, but dependence on Germany and the Russian Federation tourists' activities is still high. Although the UK was more stable, and regional markets like Bulgaria and Iran were more unstable, their positive effect on achieving the sustainable tourism goal is still weak.Research limitations/implicationsThe study is constrained by the partial coverage of 2025 data and the lack of direct indicators for environmental or social sustainability. Future research may combine these dimensions and their data to construct a more thorough and detailed evaluation for better understanding of the sustainable tourism context.Practical implicationsThe results show that for tourism in T & uuml;rkiye to be sustainable, it needs to have more diverse source markets, be better prepared for global or local crises and have plans for managing capacity, especially tourism management and seasonality. These insights can help government policymakers and local destination management bodies make long-term sustainability stronger.Social implicationsHighly concentrated tourism markets may cause revenue and employment volatility when principal source countries experience a downturn. Advocating for diversity in terms of various source markets for inbound tourism activities enhances tourism-related economic and social resilience and community welfare in terms of stable income flow and fosters inclusive growth throughout the local and national community in accordance with sustainable tourism objectives.Originality/valueThis study directly connects resilience and diversity to the management of sustainable tourism in a new destination. By integrating long-term real case data with related, respected and detailed market structure metrics, it offers novel insights into how destinations might improve their competitiveness, decreased vulnerabilities in crisis time periods and improve the sustainability of the tourism sector.Article Disorder-Engineered Hybrid Plasmonic Cavities for Emission Control of Defects in HBN(American Chemical Society, 2026-02-07) Genc, Sinan; Yucel, Oguzhan; Aglarci, Furkan; Rodriguez-Fernandez, Carlos; Yilmaz, Alpay; Caglayan, Humeyra; Bek, AlpanDefect-based quantum emitters in hexagonal boron nitride (hBN) are promising building blocks for scalable quantum photonics due to their stable single-photon emission at room temperature. However, enhancing their emission intensity and controlling the decay dynamics remain significant challenges. This study demonstrates a low-cost, scalable fabrication approach to integrate plasmonic nanocavities with defect-based quantum emitters in hBN nanoflakes. Using the thermal dewetting process, we realize two distinct configurations: stochastic Ag nanoparticles (AgNPs) on hBN flakes and hybrid plasmonic nanocavities formed by AgNPs on top of hBN flakes supported on gold/silicon dioxide (Au/SiO2) substrates. While AgNPs on bare hBN yield up to a 2-fold photoluminescence (PL) enhancement with reduced emitter lifetimes, the hybrid nanocavity architecture provides a dramatic, up to 100-fold PL enhancement and improved uniformity across multiple emitters, all without requiring deterministic positioning. Finite-difference time-domain (FDTD) simulations and time-resolved PL measurements confirm size-dependent control over decay dynamics and cavity-emitter interactions. Our versatile solution overcomes key quantum photonic device development challenges, including material integration, emission intensity optimization, and spectral multiplexity.Article Densification-Induced Chemical Reorganization and Mechanical Enhancement in Amorphous Si2BC3N(Elsevier, 2026-02) Durandurdu, MuratThe atomistic mechanisms that govern the mechanical performance of amorphous silicon-boron carbonitride (SiBCN) ceramics remain insufficiently understood, particularly regarding the role of density. Here, we employ ab initio molecular dynamics simulations to elucidate the structural evolution and mechanical response of low-density (LDA, 2.20 g/cm3) and high-density (HDA, 2.53 g/cm3) amorphous Si2BC3N prepared via melt-quench. The HDA phase exhibits markedly higher atomic packing and network connectivity, accompanied by a nontrivial chemical reorganization. Densification significantly enhances heteronuclear bonding-especially Si-C coordination-while suppressing C-C and Si-Si homopolar bonds. These changes yield substantial mechanical strengthening: the HDA phase exhibits a 48% increase in bulk modulus (130 GPa vs. 88 GPa), along with elevated Young's (266 GPa) and shear (112 GPa) moduli. Our findings reveal a clear density-structure-property relationship in amorphous SiBCN, demonstrating that densification suppresses weak self-bonded motifs and promotes a robust, interconnected atomic network. This insight provides a pathway for designing high-performance amorphous SiBCN ceramics for extreme-environment applications.Article Supervised Learning-Driven Dead Band Control of Occupant Thermostats for Energy-Efficient Residential HVAC(Elsevier, 2026-03) Savasci, Alper; Ceylan, Oguzhan; Paudyal, SumitHeating, ventilation, and air conditioning (HVAC) systems play a crucial role in demand-side management (DSM) by shaping residential electricity consumption and enabling flexible, grid-responsive operation. Thermostats in HVAC systems regulate indoor temperature as part of a closed-loop control framework, typically incorporating a fixed temperature dead band-a range around the setpoint where no action is taken-to reduce energy use and prevent frequent cycling of the HVAC system. Although essential for efficiency and equipment longevity, fixed dead bands limit adaptability, as dynamically adjusting them under varying environmental conditions remains challenging for occupants. To address this limitation, we propose a machine learning (ML)-based dead band tuning framework that optimally adjusts thermostat settings in real time. The method integrates conventional optimization with data-driven modeling: a mixed-integer linear programming (MILP) model is first used to gen erate optimal dead band values under measured outdoor temperature records (diverse seasonal weather scenarios) which are then employed to train the ML-based predictor to learn a real-time discrete dead band decision policy that approximates the MILP-optimal hysteresis-aware decisions. Among the evaluated models, Random Forest demonstrates superior predictive performance, achieving a mean squared error (MSE) of 0.0399 and a coefficient of determination (R2) of 95.75 %.Article Effects of Strain Rate and Post Processing on Mechanical Properties of Additively Manufactured AlSi10Mg Alloys(Walter de Gruyter GmbH, 2026-01-12) Karaveli, K.K.; Bal, B.The mechanical properties of AlSi10Mg alloy fabricated by laser powder bed fusion (LPBF) were investigated under different strain rates and post-processing conditions, including shot peening (SP) and stress relief (SR). Tensile tests were performed at quasistatic (0.1 s−1) and dynamic (0.015 s−1) strain rates on as-built and post-processed specimens. The results revealed that SP significantly increased the yield strength by 7.10 %, reaching 249.59 MPa, due to the induced compressive residual stresses. However, while SP slightly improved the ultimate tensile strength (UTS) by 0.25 %, it also reduced elongation at break by 18.06 %, indicating a trade-off between strength and ductility. Conversely, SR improved ductility by reducing internal stresses, leading to an elongation at break increase of 574.01 %, with a slight reduction in yield strength. The combination of SP and SR exhibited a synergistic effect, achieving a balance between strength and ductility. Strain rate sensitivity (SRS) analysis indicated that stress-relieved specimens performed better under dynamic loading conditions. These findings highlight the potential of post-processing techniques in tailoring the mechanical behavior of LPBF-produced AlSi10Mg alloys. The balanced properties achieved through combined treatments make this material particularly suitable for high-performance aerospace and automotive applications, where strength and ductility are critical under varying operational conditions. © 2025 Walter de Gruyter GmbH, Berlin/Boston.Conference Object Citation - WoS: 49Citation - Scopus: 54You May Not Reap What You Sow: How Employees' Moral Awareness Minimizes Ethical Leadership's Positive Impact on Workplace Deviance(Springer, 2017-08-02) Gok, Kubilay; Sumanth, John J.; Bommer, William H.; Demirtas, Ozgur; Arslan, Aykut; Eberhard, Jared; Yigit, AhmetAlthough a growing body of research has shown the positive impact of ethical leadership on workplace deviance, questions remain as to whether its benefits are consistent across all situations. In this investigation, we explore an important boundary condition of ethical leadership by exploring how employees' moral awareness may lessen the need for ethical leadership. Drawing on substitutes for leadership theory, we suggest that when individuals already possess a heightened level of moral awareness, ethical leadership's role in reducing deviant actions may be reduced. However, when individuals lack this strong moral disposition, ethical leadership may be instrumental in inspiring them to reduce their deviant actions. To enhance the external validity and generalizability of our findings, the current research used two large field samples of working professionals in both Turkey and the USA. Results suggest that ethical leadership's positive influence on workplace deviance is dependent upon the individual's moral awareness-helpful for those employees whose moral awareness is low, but not high. Thus, our investigation helps to build theory around the contingencies of ethical leadership and the specific audience for whom it may be more (or less) influential.Article Citation - WoS: 8Citation - Scopus: 8Writing Chemical Patterns Using Electrospun Fibers as Nanoscale Inkpots for Directed Assembly of Colloidal Nanocrystals(Royal Soc Chemistry, 2020) Kiremitler, N. Burak; Torun, Ilker; Altintas, Yemliha; Patarroyo, Javier; Demir, Hilmi Volkan; Puntes, Victor F.; Onses, M. SerdarApplications that range from electronics to biotechnology will greatly benefit from low-cost, scalable and multiplex fabrication of spatially defined arrays of colloidal inorganic nanocrystals. In this work, we present a novel additive patterning approach based on the use of electrospun nanofibers (NFs) as inkpots for end-functional polymers. The localized grafting of end-functional polymers from spatially defined nanofibers results in covalently bound chemical patterns. The main factors that determine the width of the nanopatterns are the diameter of the NF and the extent of spreading during the thermal annealing process. Lowering the surface energy of the substrates via silanization and a proper choice of the grafting conditions enable the fabrication of nanoscale patterns over centimeter length scales. The fabricated patterns of end-grafted polymers serve as the templates for spatially defined assembly of colloidal metal and metal oxide nanocrystals of varying sizes (15 to 100 nm), shapes (spherical, cube, rod), and compositions (Au, Ag, Pt, TiO2), as well as semiconductor quantum dots, including the assembly of semiconductor nanoplatelets.Article Citation - WoS: 11Citation - Scopus: 13Wireless Sensor Network-Based Communication for Cooperative Simultaneous Localization and Mapping(Pergamon-Elsevier Science Ltd, 2015-01) Tuna, Gurkan; Gungor, Vehbi Cagri; Potirakis, Stelios M.; Zeadally, SheraliThis paper presents a novel approach of using a Wireless Sensor Network (WSN) as the communication means for Multi-Robot, Cooperative, Simultaneous Localization and Mapping (CSLAM) applications investigating the associated design challenges and suggesting corresponding solutions. Although the proposed approach brings several benefits including an increased coverage and communication range, self-organization capabilities, quick deployment, and flexible architecture, the realization is interrelated with performance in terms of energy efficiency and reliability. In this respect, the applicability of the WSNs for the presented approach is investigated. Centralized and distributed map merging methods in WSN-based CSLAM are evaluated in detail and the impacts of packet delays and losses on the performance of CSLAM algorithms are shown. Additionally, the involved network congestion and contention dynamics are presented, while the effects of observation range, speed, time intervals between observations, and odometry readings on the SLAM accuracy are shown based on an extensive set of simulation studies. (C) 2014 Elsevier Ltd. All rights reserved.