WoS İndeksli Yayınlar Koleksiyonu

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Now showing 1 - 10 of 25
  • Article
    Citation - WoS: 1
    Citation - Scopus: 1
    Optical Wireless Communication in Atmosphere and Underwater: Statistical Models, Improvement Techniques, and Recent Applications
    (Institute of Electrical and Electronics Engineers Inc., 2026) Ata, Y.; Al-Sallami, F.M.; Gökçe, M.C.; Vegni, A.M.; Rajbhandari, S.; Baykal, Y.
    Optical Wireless Communication Systems (OWCSs) are becoming more popular each day, especially after numerous mobile applications are being employed within the concept of Internet of Things (IoT). OWCSs are largely used in both terrestrial and non-terrestrial environments, like underwater, air, and space scenarios. Due to the large applicability of OWCS, it represents one of the main candidate technologies for the future 6G wireless communication systems. Naturally, this market trend forces the system designers to reach the best performance in their designs, as well as optimize the cost. In this survey paper, we intend to provide information to the researchers working in this field on the statistical models adopted in OWCS, the methods and techniques used to improve their performances, mainly in outdoor environment like air, space, and underwater. In this respect, the background on theoretical aspects of OWCS, together with their benefits, limitations and challenges are presented. Performance improvement techniques employed in OWCSs, such as power increase, partial coherence, beamforming, aperture averaging, spatial diversity, and intelligent reflecting surfaces, are also introduced. Finally, we discuss the open challenges that researchers are still facing, together with future directions on next steps for a large-scale adoption of OWCS. © 1998-2012 IEEE.
  • Article
    Comprehensive Analysis of Data Augmentation Methods in Classification for an Imbalanced Epilepsy Dataset
    (Institute of Electrical and Electronics Engineers Inc., 2026) Calis, A.G.; Ergezer, H.
    Imbalanced class distribution reduces the generalizability of classifiers in EEG-based epilepsy detection. This study examines the impact of the synthetic minority oversampling technique (SMOTE) and its variants on imbalanced electroencephalography (EEG) data, utilizing an end-to-end data processing pipeline. Band-limited filtering is applied as pre-processing, and then the training data is gradually oversampled by 20% increments in four scenes. Experiments are conducted on coarse-k-nearest neighbor (Coarse-KNN), bagged trees, and artificial neural network (ANN) classifiers, and evaluation is performed using accuracy, precision, recall, F1 score, and Matthew’s correlation coefficient (MCC) metrics. In Scene #4, where the inter-class imbalance is eliminated, Borderline-SMOTE yielded the highest and most consistent results (F1 Score = 0.903–0.937, MCC = 0.830–0.894). Safe level-SMOTE (SL-SMOTE) and SMOTE/Geometric-SMOTE(G-SMOTE) produced second-ranked results. The findings demonstrate that appropriate variant selection provides consistent gains even across classifiers, making Borderline-SMOTE the recommended approach for imbalanced EEG classification. Furthermore, in the detailed analysis of ensemble sampling limits, SMOTE-based combined approaches (e.g., SL + G SMOTE) also produced consistent results. Basic descriptive statistics (mode, median, variance, and kurtosis) of the synthetic samples were found to be comparable to those of the real data, providing additional evidence of distributional consistency. © 2013 IEEE.
  • Article
    Crack Detection on Asphalt Runway Using Unmanned Aerial Vehicle Data With Non-Crack Object Removal and Deep Learning Methods
    (Pontificia Universidad Catolica de Chile, Escuela de Construccion Civil, 2025) Tapkin, S.; Tercan, E.; Bostan, A.; Şengül, G.
    Unmanned aerial vehicles are extensively utilized for image acquisition in a cheap, fast, and effective way. In this study, an automatic crack detection method with non-crack object removal and deep learning-based approaches are developed and tested on images captured by unmanned aerial vehicle. The motivation of this study is to detect either a crack exists or not in the asphalt-runway. The novelty of this study lies in integrating a non-crack artifact removal process with six classical edge detectors and comparing the resulting performance with four lightweight CNN models on the same UAV-acquired runway image dataset, enabling a unified evaluation of classical and learning-based approaches. For deep learning-based approach, four lightweight CNN models, namely GoogleNet, SqueezeNet, MobileNetv2, and ShuffleNet, are trained and the best accuracy of 87.9 is obtained whenever GoogleNet model is used. For the non-crack object removal approach, exclusion of non-crack objects from the images is the first step, where crack-detection which makes use of edge-detection techniques is the latter. In the study, Sobel, Prewitt, Canny, Laplacian of Gaussian, Roberts and Zero Cross edge detection algorithms are examined and their success rates in detecting cracks are comparatively presented. With sensitivity=0.981, specificity=0.744, accuracy=0.917, precision=0.912 and F-score=0.945 values Canny algorithm performs significantly better than others in detecting the cracks. This study provides enough evidence for the practicability of automated crack detection on unprocessed digital photographs by the results of the study conducted on asphalt runway. © (c) 2025 Tapkın, S., Tercan, E., Bostan, A. and Şengül, G. This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivatives 4.0 International License. https://creativecommons.org/licenses/by-nc-nd/4.0/
  • Article
    Visual Comfort and Indoor Environmental Quality in a Workplace Setting: A Case Study in Ankara, Türkiye
    (Univ Zagreb Fac Architecture, 2025) Avci, Ayse Nihan
    Workplaces are occasionally specified in locations where learning environments are placed together, and they are also found in common areas with various functions. Individuals need light, as it is a vital component of modern life that fosters a sense of comfort, health, and well-being. Lighting systems in interior architecture need to be designed according to the function of the space and individual needs. In cases where natural lighting is insufficient, comfortable, healthy, and prosperous places are designed with mixed-use lighting. Factors affecting indoor environmental quality, such as sound, color, and thermal comfort, should be designed together with lighting. This study aims to investigate the indoor environmental quality parameters of the specified workplace regarding visual comfort. Students voluntarily participated in the study. An experimental space on the first floor of the building, known as the "Common Building" of & Ccedil;ankaya University and serving as a connection point for the faculties, was chosen for the study. This type of research is crucial for ensuring that indoor environmental quality parameters are effectively utilized indoors to enhance human-centric interior design.
  • Article
    Forecasting the Methane Yield of a Commercial-Scale Anaerobic Digestor Based on the Biomethane Potential of Feedstocks
    (Multidisciplinary Digital Publishing Institute (MDPI), 2025) Türker Bayrak, Ö.T.; Uludaǧ-Demirer, S.; Xu, M.; Liao, W.; Bayrak, Ozlem Turker
    With rising energy demand and the need for sustainable waste treatment, anaerobic digestion (AD) has emerged as a key technology for converting organic residues into renewable energy. However, predicting methane yield in full-scale facilities remains challenging due to the complexity of AD processes, the variability of feedstocks, and the impracticality of frequent biochemical methane potential (BMP) testing. In this study, we developed a simple, data-driven approach to forecast methane production in a commercial-scale digester co-digesting manure and food waste. The model employs weekly cumulative BMP of feedstock mixtures, calculated from literature values, as the explanatory variable. The model achieved an R2 of 0.70 and a forecast mean absolute percentage error (MAPE) of 7.4, indicating its potential for full-scale AD prediction. Importantly, the analysis revealed a long-run equilibrium between BMP and methane yield, with deviations corrected within roughly one month—closely matching the system’s hydraulic retention time. These findings demonstrate that literature-based BMP values can be used to reliably predict methane yield in operating AD systems, offering a low-cost and scalable tool to support decision-making in waste management and biogas plant operations. © 2025 by the authors.
  • Article
    Citation - WoS: 14
    Citation - Scopus: 18
    Existence Theory and Numerical Simulation of HIV-I Cure Model with New Fractional Derivative Possessing a Non-Singular Kernel
    (Springeropen, 2019) Aliyu, Aliyu Lsa; Alshomrani, Ali Saleh; Li, Yongjin; Inc, Mustafa; Baleanu, Dumitru
    In this research work, a mathematical model related to HIV-I cure infection therapy consisting of three populations is investigated from the fractional calculus viewpoint. Fractional version of the model under consideration has been proposed. The proposed model is examined by using the Atangana-Baleanu fractional operator in the Caputo sense (ABC). The theory of Picard-Lindelof has been employed to prove existence and uniqueness of the special solutions of the proposed fractional-order model. Further, it is also shown that the non-negative hyper-plane a positively invariant region for the underlying model. Finally, to analyze the results, some numerical simulations are carried out via a numerical technique recently devised for finding approximate solutions of fractional-order dynamical systems. Upon comparison of the numerical simulations, it has been demonstrated that the proposed fractional-order model is more accurate than its classical version. All the necessary computations have been performed using MATLAB R2018a with double precision arithmetic.
  • Article
    Citation - WoS: 51
    Citation - Scopus: 66
    Existence 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
    Integrating the Seljuk Cultural Layer Into Contemporary Life: The Case of Niğde Historic City Center
    (Istanbul Univ, Research Inst Turkology, Dept Art History, 2025) Yavaşcan, Emel Efe; Urak, Zehra Gediz
    Günümüz tarihî kent merkezleri, yer altı ve yer üstündeki tarihî izleriyle, kültürel zenginlikleri ve özgün kimlikle8 rinin yanı sıra, “yerin ruhu”nu yansıtan kentsel hafıza alanlarıdır. Çok katmanlı bu tarihî kent merkezleri, kültür varlıklarının fiziksel ve işlevsel eskimesi, sosyo8kültürel ve ekonomik doku bozulmaları, koruma problemleri vb. sorunlarla giderek çöküntü yerleri hâline gelmektedir. Bu sorunları barındıran Niğde kentinde yapılmış koruma uygulamalarında, kentin yer altında ve yer üstünde bulunan katmanlarının dikkate alınmamış olması çalışmada problem olarak belirlenmiştir. Kentli tarafından tepe olarak algılanan çalışma alanı uzun zamandır çöküntü alanı niteliğindedir. Çalışmanın amacı, Niğde Tarihî Kent Merkezi’nin Selçuklu Dönemi’ne ait tarihî katmanını analiz etmek, haritalan8 dırmak ve bu katmanı çağdaş koruma uygulamalarına entegre etmeye yönelik öneriler geliştirmektir. Araştırma verileri, kentin tarihî gelişiminde en belirleyici dönemin Selçuklu Dönemi olduğunu göstermektedir. Bu sebeple çalışma kapsamında bu katman odak alınmıştır. Ayrıca, diğer tarihî katmanların da korunarak günlük yaşama kazandırılmasına katkı sağlamak, bu çalışmanın bir diğer hedefidir. Bu bağlamda, Selçuklu Dönemi’ne ait yer üstü ve yer altı değerlerinin sürdürülebilir korunmasına yönelik öneriler geliştirilmiştir.
  • Editorial
    Citation - WoS: 1
    Citation - Scopus: 2
    The Role of Cultural Heritage in Resilience Planning: Evidence From 100 Resilient Cities
    (Firenze Univ Press, 2025) Altay-Kaya, Deniz; Yesilbag, Damla
    As a container of accumulated experiences, cultural heritage connects past, present and future by transmitting knowledge to future generations through tangible/intangible assets. With this potential, cultural heritage can significantly contribute to community resilience, yet available resilience strategy documents place limited emphasis on cultural heritage. Based on this observed lack of systematic consideration, this paper analyses the resilience strategy documents presented in the 100 Resilient Cities Programme, and discerns six approaches towards cultural heritage, namely ignorance, economic development tool, identity construction, social component, physical integration tool, and comprehensive consideration. The paper discusses further ways cultural heritage can enhance community resilience.
  • Editorial
    Advanced Theoretical and Applied Studies of Fractional Differential Equations 2013
    (Hindawi Publishing Corporation, 2014) Baleanu, Dumitru; Trujillo, Juan J.; Ahmad, Bashir