WoS İndeksli Yayınlar Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/8653

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A First-Order System of Equations on a Compact Star Graph
(Ankara Univ, FAC Sci, 2025) Mutlu, Gokhan; Ugulu, Ekin
This study concerns a boundary value problem generated by a system of first-order differential equations and some symmetric boundary conditions on a compact star graph. Unlike usual quantum graph Hamiltonians, the Hamiltonian considered in this paper acts on vector-valued functions living on the edges. Appropriate vertex conditions are introduced to ensure the corresponding boundary value problem is symmetric. In particular, coupling and separated conditions are imposed at the central and boundary vertices, respectively. Moreover, the general form of the vertex conditions at the central vertex is discussed. Finally, the characteristic function is constructed for the symmetric boundary value problem generated by the first-order system and specific coupling vertex conditions.
A Meta-Heuristic Stochastic Algorithm for the Numerical Treatment of Cancer Model through the Chemotherapy and Stem Cells
(Elsevier, 2026) Baleanu, Dumitru; Defterli, Ozlem; Sabir, Zulqurnain; Abdelkawy, M. A.
Objective: The aim of current research is to present the numerical performances of the cancer treatment model based on chemotherapy and stem cells using one of the heuristic computing neural network procedures. The cancer treatment model through chemotherapy and stem cells is categorized into stem cells, affected cells, tumor cells, and chemotherapy-based concentration drug. Method: A process of artificial neural network is applied using the hybrid optimization of global and local search schemes, which are taken as genetic algorithm (GA) and an active set (AS). An error-based fitness function is designed by using the differential model and then optimized by the hybridization of both global and local search schemes. GA is applied to exploit the global result and give a primary guess to the AS that further improves the results locally. AS is rooted in the GA, where GA produces new populaces and AS optimizes the fitness function for every individual. The hybridization of these two schemes is used iteratively for purifying the results. Ten numbers of neurons and log-sigmoid activation functions has been used to solve the cancer treatment model based on chemotherapy and stem cells. Results: For the correctness of the stochastic solver, the obtained numerical results have been compared with any traditional scheme. Moreover, the reliability and capability of the scheme are performed through the absolute error around 10-05 to 10-07 along with different statistical approaches for solving the mathematical model. Novelty: The proposed artificial neural network structure along with the hybrid optimization of global and local search schemes has never been implemented before to solve the cancer treatment model based on chemotherapy and stem cells.
A Soft Sensor-Integrated Cell Stretching Device for Precise and Reproducible Mechanotransduction
(Royal Soc, 2026) Yildiz, Solen Kumbay; Akar, Samet; Ozturk, Emre; Dincer, Pervin; Uyanik, Ismail; Duz, Nilufer
Mechanical stretch is a fundamental regulator of cell fate, yet in vitro replication remains challenging because conventional stretchers deliver non-uniform strain and ignore batch-to-batch variations in substrate stiffness-so the stress actually experienced by cells varies unpredictably. We introduce the first biaxial cell-stretching platform that couples an embedded soft resistive micro-channel sensor with high-frequency closed-loop control. Real-time deformation read-out (60 Hz) drives a 24 kHz actuator loop to compensate for polydimethylsiloxane (PDMS) moduli spanning an order of magnitude, delivering user-defined triangular or square waveforms (5-20% amplitude; 0.5-10 s period) with less than 2% steady-state error. Closed-loop operation maintains strain-invariant membrane stress within +/- 5%, reducing well-to-well variability threefold compared with open-loop actuation. Biological validation using immortalized human myoblasts exposed to 10% cyclic stretch for 4 h produced a significant upregulation of YAP/TAZ target genes (C-MYC, MYL9, DIAPH1, ANKRD1; p < 0.001), confirming mechanotransductive efficacy. The platform's modular architecture accommodates stiffness-tunable hydrogels and live imaging, offering a reproducible tool for mechanobiology, tissue engineering, disease modelling and personalized mechanotherapy.
Configurations of a Drop Stuck between Two Parallel Laminae under Zero Gravity
(Springer INT Publ AG, 2026) Kessi, Arezki; Adjabi, Yassine; Jarad, Fahd; Namazov, Atif
In a zero-gravity environment and under static conditions, the interface between a drop and the surrounding fluid forms a surface of constant mean curvature. This concept is based on a general parametric representation proposed by Kenmotsu in 1980 with further developments discussed in 2003. In this article, we focus on studying the resulting axisymmetric surfaces in detail. Additionally, we rigorously characterize various configurations of a drop that is trapped between two parallel plates in the absence of gravity, while maintaining a fixed volume. These configurations depend on the contact angle with the plates (a phenomenological parameter) and the gap between them (a controllable parameter). Special attention is given to the case where the contact angle is equal to pi/2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \pi /2 $$\end{document}.
Effects of Communication Competency and Self-Esteem on Gaming Addiction Symptoms
(Turkish Green Crescent Soc, 2022) Bulut, Merve Topcu; Salis, Irem
Gaming behavior has become more and more popular, but there has not been any research that considers the relationship between communication competency, self-esteem, and internet gaming addiction symptoms. The main aim of the ongoing study was to assess the associations between internet gaming addiction symptoms, self-esteem, and dimensions of communication competency. For this purpose, data were obtained from 455 individuals (47.7% females and 52.3% males) who reported that they are involved in gaming. In this study, participants were assessed with the following scale set: Sociodemographic Form, Internet Gaming Disorder Scale-Short Form, Communicative Competence Scale, and Rosenberg Self-Esteem Scale. Analyses indicated that the internet gaming disorder total score has a significant and negative correlation with self-esteem and dimensions of communication competency. Besides these results, self-esteem and listening competency of dimensions of communication competency have been found as a significant predictor of internet gaming disorder total score. In the literature, there has been only finite published research analyzing the dimensions of communication competency, self-esteem, and internet gaming disorder.
Hurwitz Split Quaternions
(Wiley, 2026) Ozbay, Neslihan Aysen
In this work, we introduce the set of Hurwitz split quaternions, , which is an extension of the split quaternions over the integers, . In comparison to , the Hurwitz splits only have integer or half-integer coefficients, not both. We demonstrate that it has a ring structure and examine certain features of this notion by pointing out the differences from . We also provide the matrix representation of the ring of Hurwitz split quaternions. In addition, we study some of its prime ideals and show that this ring is Noetherian. Then we describe the set of integer-valued polynomials over to be . Once we prove forms a ring, we investigate some essential properties of this ring.
Citation - WoS: 2
Kinematic Analysis and Position Control of Motor Grader Blade Mechanism for Automatic Levelling1
(IEEE, 2022) Ergezer, Halit; Ozkan, Ekin Cansu
In this study, mechanism analysis, which is one of the necessary steps for automatic function control in construction machines, is emphasized. Motor grader construction machine has been chosen because there are a minimal number of studies in the literature. The blade mechanism of the motor grader has high degrees of freedom; it can perform various rotations and orientations in the XYZ axis. For this mechanism, which is very challenging to control and make kinematic analysis, functions that specify the motion behavior of the cutting-edge points are obtained using the polynomial surface fitting method. PI controllers were created for the MIMO system to reduce the existing steady-state error. Tests were performed for various scenarios on the actual machine, and the results were compared.
Pseudo-Static Finite-Element Assessment of Seismic Soil-Pipeline Interaction in Multi-Line Buried Pipelines
(MDPI, 2026) Sengor, Mahmut; Alrubaye, Maryam; Almusawi, Ali
This study investigates the seismic response of double- and triple-buried steel pipeline systems using finite-element modeling in RS2, with particular emphasis on soil-pipeline interaction and symmetry-breaking behavior under pseudo-static seismic loading. Although the pipeline systems are initially symmetric in geometry, material properties, and boundary conditions, the analysis demonstrates that directional seismic excitation induces quantitatively measurable asymmetric responses in shear force, displacement, and spacing due to nonlinear soil-pipeline interaction. Five parametric scenarios were examined, including burial depth (1-5 m), pipeline diameter (8-56 in.), groundwater table (1.4-20 m), peak ground acceleration (0.1-0.6 g), and soil type. The results show that maximum shear forces increase with burial depth and diameter, reaching approximately 15-17 kN in clayey soils at a PGA of 0.4 g, whereas sandy and heterogeneous soils produce lower shear forces (approximate to 12-14 kN). Horizontal displacements are strongly governed by groundwater and PGA, increasing from about 1.2-1.8 m in dry or deep groundwater conditions to more than 2.8 m for shallow groundwater and exceeding 5 m at PGA = 0.6 g. Triple-pipeline systems exhibit higher shear demand due to confinement effects, with the middle pipeline often developing the largest shear force, while the pipeline facing the seismic load consistently experiences the greatest displacement. This study makes two primary contributions. First, it demonstrates that initially symmetric multilined buried pipeline systems exhibit systematic, quantifiable symmetry-breaking behavior under directional seismic loading, manifested as unequal shear forces, displacements, and interaction effects among adjacent pipelines. Second, it presents an integrated multi-parameter coupling analysis that simultaneously accounts for burial depth, pipeline diameter, groundwater level, soil type, and peak ground acceleration, revealing interaction mechanisms that cannot be captured through single-parameter or single-pipeline assessments.
Raising Awareness of Acoustics and Soundscaping among Interior Architecture Students and Professionals: A Brief Review and Roadmap
(INT Inst Acoustics & Vibration, 2025) Dokmeci Yorukoglu, Papatya Nur
Acoustics play a vital role in how people experience spaces, yet it is often overlooked in interior architecture education and practice. Many professionals and students focus primarily on visual, technical, and structural elements, missing the impact that sound has on well-being, spatial quality, and experience. This study reviews existing research on the importance of acoustics and soundscaping in interior architecture education and practice, highlighting gaps in awareness and common practice. Based on these insights, a practical roadmap is proposed to better integrate acoustics into education and professional practice. By incorporating sound-conscious design projects in studio environments during undergraduate education and supporting interdisciplinary collaboration with adapting new technologies, this study aims to bridge the gap between theory and practice. Raising awareness at both the academic and professional levels will help create more acoustically comfortable and enhanced environments that would support user satisfaction and well-being.
RETRACTION: Solar Radiation Effect on PCM Performance in the Building Applications: The Collector Energy-Saving Potential Using CF-MWCNTs and CF-GNPs
(Elsevier, 2026) Mohammad Sajadi, S.; Chen, Liangliang; Baleanu, Dumitru; Alrabaiah, Hussam; Aldabesh, Abdulmajeed; Sajadi, S. Mohammad; Liu, Fenghua
Seismic Vulnerability Assessment of a Historic Masonry-Timber Building: The Case of Katharina Hunting Mansion
(Taylor & Francis Ltd, 2026) Cosgun, Turgay; Sayin, Baris; Ormecioglu, Tevfik Oguz; Samadi, Kamran; Akan, Asli Er; Haydaroglu, Furkan; Er Akan, Aslı; Uzdil, Oguz
Historic buildings are clear testaments to human civilization, and their preservation is essential for the world's cultural heritage. This study examines a unique heritage building in Turkiye that represents a brief period of Russian rule and its architectural style. The structure, the historic Katharina Hunting Mansion, was constructed by the Russians in the Sarıkamış district of Kars Province following the 1877-1878 Ottoman-Russian War. The mansion features a unique Scandinavian saddle notch (known as 'v chashu' in Russian and 'çantı system' in the Black Sea region). A survey was conducted to determine the deformations of the building, which included the preparation of plans, facades, and sections. The architectural investigation revealed that yellow pine, a common species in the region's forests, was used as the construction material. Architectural restoration proposals were developed based on the results of seismic analyses and the classification of architectural elements as either later additions or missing components. A unique methodology that combines various seismic analysis methods in accordance with the applicable local seismic codes was performed for the seismic performance assessment. For this purpose, the finite element model of the historic mansion was subjected to linear, nonlinear, and kinematic analyses. In the analyses, both the local seismic code TBEC-2018 and the SRMGHS-2017 guideline were considered, due to the historical status and structural system of the building. This process determined whether the structure meets the Limited Damage and Controlled Damage performance objectives for DD-3 and DD-2 earthquake levels, as envisaged in the local seismic codes. The linear analysis revealed that the building met the seismic performance objective with respect to inter-story drifts. Furthermore, the results of the nonlinear pushover analysis also indicated that the building satisfied performance objectives regarding shear forces and corresponding displacements. Moreover, the kinematic analysis determined that all local collapse mechanisms occurred at DD-2 and DD-3 earthquake levels, except for the overturning mechanism under DD-2. Therefore, the restoration proposals recommended using clamping at the wall joints to prevent potential local collapse. This study contributes to the field by presenting a comprehensive methodology for the seismic assessment of historic masonry-timber buildings. Additionally, the seismic performance of this historic building, featuring a unique combination of masonry and timber elements, was found to be generally satisfactory and compliant with current local codes.
Soundscape Evaluation of Urban Interiors by Perceived Restorativeness Soundscape Scale-Prss
(INT Inst Acoustics & Vibration, 2025) Dokmeci Yorukoglu, Papatya Nur; Batur, Gulben Gizem
Enhanced spatial experience should support well-being, decrease users' stress, and foster a healthy connection with their surroundings. This study aims to explore the mental restoration properties and soundscape quality of urban interior spaces by assessing the interaction between auditory and visual perception. A case study was conducted in two selected urban interior spaces, and on-site surveys were administered to 92 randomly selected participants. The findings indicate that individuals in the green-dominant environment rated both the soundscape and visual scenery more favorably than those in the gray-dominant setting. In contrast, participants in the gray-dominant space found the soundscape and visual scenery more disruptive. The study also revealed a strong correlation between audio-visual elements and spatial experience, with participants' perceptions of sound and visuals aligning closely. Additionally, based on the Perceived Restorativeness Soundscape Scale (PRSS), the green-dominant space exhibited higher perceived restorativeness soundscape quality scores than the gray-dominant space.
System-Level Prediction and Optimization of Cyclone Separator Performance Using a Hybrid CFD-DEM-ANN Approach
(MDPI, 2026) Kocak, Eyup
In this study, the separation performance of cyclone separators with different geometric configurations was investigated using a hybrid approach that combines Computational Fluid Dynamics, the Discrete Element Method, and Artificial Neural Networks. In the first stage, the flow field was solved using the Reynolds-Averaged Navier-Stokes equations together with the Reynolds Stress Model turbulence closure, and particle motion was evaluated in detail through DEM. To examine the effect of geometric parameters, the inlet aspect ratio, vortex finder diameter, and cylinder height were systematically assessed. The results revealed the formation of a pronounced Rankine-type vortex structure inside the cyclone and showed that secondary flow regions intensified as the vortex finder diameter and cylinder height increased, thereby reducing the separation efficiency. In the inlet section, an optimal aspect ratio was identified. In the second stage, an ANN model was developed to expand the limited dataset obtained from the CFD-DEM analyses. By optimizing the activation function and the number of neurons, the best performance was achieved with a ReLU-based neural network containing a single hidden neuron, reaching a test-set accuracy of approximately R2 approximate to 0.991 and an overall fit of R2 approximate to 0.895. The ANN model also captured interaction trends between flow velocity and geometry that could not be observed with the limited CFD dataset. This hybrid approach provides an effective and low-cost method for performance prediction and optimization in cyclone separator design.
The Effects of Different Kinds of Brand Mascots Used in Advertisements on Visual Attention: An Experımental Study
(Inst Superior entre Douro & Vouga, 2025) Yalcin, Mustafa; Ulan, Sevilay; Gecit, Erdem
Mascots, which are frequently featured in advertising campaigns, can be said to be an important visual tool that enables the brand to attract attention and differentiate itself from its competitors. In a competitive market environment, brands addressing consumers through mascots can strengthen the positive image of the brand by gaining a place in their minds and hearts. For this reason, it is an important research topic to examine the visual attraction levels of brand mascots that can represent the identity and personality of the brand. In this study, the visual attention level of consumers for different types of brand mascots used in Instagram advertisements was determined by an experimental method. In the scope of the research, Mascot samples representing four different mascot types: animal, robot, object, and fantastic hero were selected. Through these mascot samples, the visual attention levels of 30 participants were measured with the eye tracking device, which is one of the biometric measurement methods. In this context, the participants' heat map, initial focus time, total focus time, and number of looks were recorded. Accordingly, the brand mascots, Compared to the product image, product information, and campaign information images, it has been observed that low visual attractiveness levels are low. On the other hand, it was concluded that the attraction level of object and animal type mascots is higher than robot and fantastic type mascots.
Citation - WoS: 1
Using Quick Response (Qr) Codes as an Indoor Wayfinding Tool: Benefits and Limitations
(Middle East Technical Univ, 2022) Imamoglu, Cagri; Tunger, Cetin

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