Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article FW-S3PFCM: Feature-Weighted Safe-Semi Possibilistic Fuzzy C-Means Clustering(Springer, 2026) Khezri, Shirin; Aghazadeh, Nasser; Hashemzadeh, Mahdi; Golzari Oskouei, AminThe safe semi-supervised fuzzy c-means clustering (S3FCM) method is a well-known clustering method that can produce successful results by incorporating prior knowledge of the class distribution. Its process is fast and simple but still has two limitations. The first issue is that it gives equal weight to all data features, while in real-world applications, different features usually have different importance. Secondly, S3FCM is very sensitive to noise and outliers. This paper proposes an extension of the S3FCM, entitled FW-S3PFCM, to mitigate these shortcomings. The proposed method uses a local feature weighting scheme to consider the different feature weights in the clustering process. Additionally, a possibilistic version of the S3FCM is designed to reduce the sensitivity to noise and outliers. The effectiveness of the proposed method is comprehensively evaluated on various benchmark datasets, and its performance is compared with the state-of-the-arts methods. To practically asses the FW-S3FCM, a real-world dataset of brain MRI images and its segmentation performance are analyzed as well. The average Accuracy, F1-score, Sensitivity, and Precision measures obtained by FW-S3FCM are 0.9682, 0.9826, 0.9743, and 0.9925, respectively, which are better than the competitors' performance.Article Alterations in Secondary Lipids Are Associated with Neuroinflammation in the Brain of Neu1-Deficient Mice(Springer, 2026) Ada, Ebru; Seyrantepe, VolkanNeu1 (lysosomal sialidase 1) is essential for removing sialic acid from oligosaccharides and glycoconjugates. Neu1 deficiency impairs lysosomal digestion, leading to sialidosis and sialoglycoprotein accumulation. It also increases lipids, including gangliosides GM3, GD3, GM4, and LM1, in the kidney, liver, and spleen. Neu1-/- mice display symptoms resembling Type II sialidosis, including enlarged spleen and liver, kidney issues, neurological problems, spinal defects, and oligosaccharide buildup. The study examined secondary lipid alterations and inflammation in the cortex and cerebellum of these mice. Lipidomic, molecular, and immunohistochemical analyses of tissues from 2 and 5 M Neu1-/- mice revealed reduced levels of lipids, including PC, PE, PS, and CL, along with increased pro-inflammatory cytokines and loss of oligodendrocytes and neurons. Signs of astrogliosis and microgliosis emerged in specific brain regions. These results indicate that reduced levels of glycerophospholipids could serve as an indicator of inflammation in sialidosis mice. Future research should investigate therapies targeting these lipid changes, as modulating glycerophospholipids might slow disease progression in sialidosis patients.Article Mass Spectrometric Profiling Reveals Alterations in N-Glycans and O-Glycans in Tay-Sachs Disease Under Autophagy-Induced Conditions(Springer, 2025) Can, Melike; Basirli, Hande; Jin, Chunsheng; Karlsson, Niclas G.; Bojar, Daniel; Seyrantepe, VolkanTay-Sachs disease is a rare neurodegenerative disorder caused by mutations in the HEXA gene. The HEXA gene encodes the alpha-subunit of the enzyme beta-hexosaminidase A, which degrades GM2 ganglioside. Previously, we identified impaired autophagy in the brains of a mouse model of Tay-Sachs disease, which exhibited neuropathological and clinical abnormalities. Moreover, we demonstrated autophagosome clearance in Tay-Sachs cells under lithium-induced conditions. Here, we further aimed to evaluate N- and O-glycan changes in these cells and examine whether glycan alterations are linked to ER stress. The profiles of N- and O-glycans were analyzed using LC-MS/MS in fibroblasts and neuroglial cells from 5-month-old Hexa-/-Neu3-/- mice and neuroglial cells from Tay-Sachs patients under lithium induction and nutrient deprivation. The expression levels of ER stress-related markers were assessed using qRT-PCR and Western blot analyses. We demonstrated higher levels of high mannose and lower levels of complex types of N-glycans, along with increased O-glycan levels in Tay-Sachs cells. Compared to control groups, we observed upregulated expression of endoplasmic reticulum (ER) stress-related markers, CHOP and ATF-6, in Tay-Sachs cells. Our study demonstrated that autophagy induction causes the degradation of accumulated high-mannose N-glycans and O-glycans, which is associated with the downregulation of ER stress-related genes in Tay-Sachs cells. Our study is the first to show this phenomenon in Tay-Sachs cells and suggests the presence of ER stress-mediated autophagy. Therefore, targeting glycans through autophagy induction could offer therapeutic benefits to patients with Tay-Sachs disease in future studies.Article Performance of Sheet Pile Walls With Rubber-Modified Backfill(Springer, 2025) Ecemis, Nurhan; Kadekeshova, Kuralay; Khlaif, Ali HamidThis study investigates the behavior of clean sand and sand-rubber mixtures used as backfill materials behind sheet pile walls under vertical loads. Physical model experiments were conducted to assess lateral displacement and pressure for backfills containing 10% granulated rubber (2.5-5 mm) under both dry and saturated conditions, and across varying backfill inclination angles. To complement the experiments, discrete element method (DEM) simulations were performed to capture the micromechanical behavior of sand-rubber mixtures, enabling analysis of particle-scale interactions. Material stiffness and friction parameters were calibrated through direct shear tests to ensure computational efficiency and accurate representation. Comparative analyses were conducted between the DEM simulations and the physical sheet pile tests across various sand-rubber backfill configurations. The results suggest that sand-rubber mixtures offer a practical and sustainable alternative for backfill applications, improving both mechanical performance and pressure mitigation. Furthermore, force chain development and deformation patterns were thoroughly examined to understand the role of micro parameters; such as particle contact behavior, porosity, internal friction, and stiffness of the rubber-sand composite backfill in reducing active earth pressure against sheet pile walls.Article Citation - WoS: 2Citation - Scopus: 2Microstructural Evolution and Mechanical Performance of Dual-Phase Steels Under Fiber Laser Welding: Effects of Heat Input and Weld Penetration(Springer, 2025) Tuncel, Oguz; Davut, Kemal; Aydin, HakanThis study investigates the effects of fiber laser welding (FLW) parameters on the microstructural evolution and mechanical properties of DP800, DP1000, and DP1200 dual-phase steels, focusing on the role of heat input. Welding was performed using laser powers ranging from 1500 to 3000 W and welding speeds between 20 and 100 mm/s, resulting in heat inputs from 18 to 120 J/mm. Optimal welding conditions were identified as 55 J/mm for DP800, 120 J/mm for DP1000, and 53 J/mm for DP1200, which ensured full penetration and minimized HAZ softening. Detailed microstructural analysis using SEM and EBSD revealed significant transformations in the heat-affected zone (HAZ), including martensite degradation, grain coarsening, and tempered martensite formation, particularly in DP1200 steel, where hardness reductions reached up to 29%. Tensile tests demonstrated that while DP800 and DP1000 joints primarily failed within the base material (BM) with ductile fracture characteristics, DP1200 joints fractured within the HAZ due to a combination of brittle cleavage and ductile dimples caused by martensite breakdown and carbide precipitation. The findings underscore the necessity of optimizing welding parameters to control HAZ softening and preserve mechanical performance. By systematically analyzing the interplay between heat input, microstructure, and mechanical properties across different DP steel grades, this research provides a comprehensive understanding of how FLW conditions influence joint integrity, offering valuable guidance for designing robust welding strategies in advanced engineering applications.Article Deposition of (La,Sr)CoO₃-δ and (La,Sr)₂CoO₄-δ Cathode Layers on Gadolinia-Doped Ceria by Electrospray Deposition(Springer, 2025) Ergen, Emre; Akkurt, SedatLa-, Sr-, and Co-based oxides have proven their performances in the cathode layers of intermediate temperature levels of solid oxide fuel cells (SOFC), and hence have been frequently studied. They are deposited on the electrolyte layer by chemical vapor deposition (CVD), screen printing, pulsed laser deposition (PLD), etc. The electrospray deposition (ESD) proved itself as an effective and facile method for cathode deposition. Cathode layers deposited on gadolinia-doped ceria (GDC) with the compositions of (La0.5Sr0.5)CoO3, (La0.8Sr0.2)CoO3, (La0.5Sr0.5)2CoO4, and (La0.8Sr0.2)2CoO4 are known to provide low resistance values which are critical in cell performance. In this study, ESD is used for the first time as the coating method of these compositions. Area-specific resistance (ASR) measurements made by electrochemical impedance spectroscopy (EIS) showed promising results. Particularly, the sample coated in (La0.5Sr0.5)CoO3 composition showed an ASR value of 0.11 Omega.cm2 at 700 degrees C. ESD showed the ability to control the cathode coating microstructure by controlling the spraying parameters.Article Citation - WoS: 7Citation - Scopus: 9A Holistic Overview of the Applications of Grace-Observed Terrestrial Water Storage in Hydrology and Climate Science(Springer, 2025) Khorrami, Behnam; Gunduz, OrhanTerrestrial Water Storage (TWS) represents a vital element of the hydrological cycle, with its fluctuations significantly impacting the climate of the Earth and its ecological balance. Since its launch in 2002, the Gravity Recovery and Climate Experiment (GRACE) satellite mission has revolutionized the ability to observe and analyze large-scale mass changes within Earth's system components. This paper offers a comprehensive and current overview of GRACE satellite gravimetry, highlighting its relevance to hydrological and climate-related studies. It outlines the fundamental measurement principles of the GRACE mission, provides an in-depth explanation of GRACE data products (including spherical harmonic and mascon solutions), examines emerging trends in GRACE-based research, and reviews key applications in hydrology and climate science. Additionally, it addresses the major challenges in utilizing GRACE data and explores promising avenues for future research and applications.Article Citation - WoS: 2Vis-Assist: Computer Vision and Haptic Feedback-Based Wearable Assistive Device for Visually Impaired(Springer, 2025) Dede, Ibrahim; Gumus, AbdurrahmanVisual impairment affects millions of people worldwide, posing significant challenges in their daily lives and personal safety. While assistive technologies, both wearable and non-wearable, can help mitigate these challenges, wearable devices offer the advantage of hands-free operation. In this context, we present Vis-Assist, a novel wearable visual assistive device capable of detecting and classifying objects, measuring their distances, and providing real-time haptic feedback through a vibration motor array, all using an integrated low-cost computational unit without the need for external servers. Our study distinguishes itself by utilizing haptic feedback to convey object information, allowing visually impaired individuals to discern between 19 different object classes following a brief training period. Haptic feedback offers an alternative to audio that doesn't block hearing and can be used alongside it, serving as a complementary solution. The performance of the developed wearable device was evaluated through two types of experiments with four participants. The results demonstrate that users can identify the location of objects and thereby prevent collisions with obstacles. The experiments conducted demonstrate that users, on average, can locate a predefined object, such as a chair, within a 40 m2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\hbox {m}<^>{2}$$\end{document} vacant space in under 94 seconds. Furthermore, users exhibit proficiency in finding objects while navigating around obstacles in the same environment, achieving this task in less than 121 seconds on average. The system developed here has high potential to help the self-navigation of visually impaired people and make their daily lives easier. To facilitate further research in this field, the complete source code for this study has been made publicly available on GitHub.Article Citation - WoS: 1Citation - Scopus: 1Efficiency Evaluation of Optimal Tlcd and Tmd for the Seismic Response Reduction of Buildings Considering Soil-Structure Interaction Effect(Springer, 2025) Roozbahan, Mostafa; Masnata, Chiara; Turan, Guersoy; Pirrotta, AntoninaTuned Mass Dampers (TMDs) and Tuned Liquid Column Dampers (TLCDs) are widely recognized passive vibration control devices used to reduce structural vibrations. While TMDs have been extensively studied for mitigating the seismic responses of multi-story buildings considering Soil-Structure Interaction (SSI), the efficiency of TLCDs in these conditions remains largely unexplored. Furthermore, a direct comparison of these devices under similar conditions has not been conducted. Then, to address these gaps, this study investigates the efficiency of TLCDs and compares them to TMDs in reducing seismic-induced vibrations, focusing on the influence of SSI. The control performance of both devices depends on various parameters, primarily the frequency and damping ratios. Therefore, the Mouth Brooding Fish (MBF) metaheuristic algorithm is applied to optimize these parameters, accounting for SSI effects. To evaluate the different efficiency between TMDs and TLCDs under SSI conditions, three types of shear buildings are considered: an eight-story, a sixteen-story and a forty-story structure. The seismic responses of the uncontrolled, TMD-controlled, and TLCD-controlled buildings are examined under twenty-two far-field and fourteen near-field earthquakes, considering both fixed-base and flexible-base scenarios. Results indicate that while both devices significantly reduce seismic responses, TMDs generally outperform TLCDs, particularly in taller buildings where the impact of SSI is more significant. Further, this study highlights that neglecting SSI in the design of these devices may lead to an overestimation of their effectiveness, especially in softer soils, emphasizing the importance of considering SSI in the optimization process for accurate and reliable outcomes.Article Ggnn: Group-Guided Nearest Neighbors for Efficient Image Matching(Springer, 2025) Cine, Ersin; Bastanlar, Yalin; Ozuysal, MustafaThe widely adopted image matching approach remains dependent on exhaustive matching of local features across images. Existing methods aiming to improve efficiency either approximate nearest neighbor (NN) search, compromising accuracy, or apply filtering only after establishing tentative matches, which restricts potential efficiency gains. We challenge the assumption that exhaustive NN search is necessary by proposing a more efficient hierarchical approach that maintains matching accuracy without relying on full-scale NN search. Our key insight is that efficiently identifying sufficiently similar, geometrically meaningful feature matches-rather than the most similar but geometrically random ones-can improve or maintain performance at a lower computational cost. We propose a novel method, Group-Guided Nearest Neighbors (GGNN), which matches groups of features first and then matches individual features only within these matched groups. This hierarchical pipeline reduces the computational complexity of feature matching from \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\theta (n<^>2)$$\end{document} to \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\theta (n \sqrt{n})$$\end{document}, significantly improving efficiency. Experimental results on homography estimation demonstrate that GGNN outperforms standard NN search while achieving performance comparable to state-of-the-art methods. Additionally, we formulate GGNN as a general framework, where conventional NN search is a special case with a single global feature group. This formulation provides a continuum of feature matching methods with varying computational costs, enabling automatic selection based on a given time budget.