Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/8651
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Article Beam Shaping on a Fluorescent On-Chip Imaging System(IOP Publishing Ltd, 2026) Arpali, Caglar; Arpali, Serap AltayThe fluorescent on-chip imaging system differs from a conventional fluorescent microscope in terms of the imaging method because the sample is directly placed on the imaging sensor (i.e., charge-coupled device (CCD)). While this imaging modality presents several advantages, including a wide field of view and rapid scanning speed, it can be difficult to detect certain particles in dense and scattering environments, such as whole blood and tissue. These difficulties lead to a decreased signal-to-noise ratio (SNR) in the captured images, influenced by both the medium's light-transmitting capability and the excitation techniques used. In this paper, we quantitatively examine the effect of beam shaping techniques on a fluorescent on-chip imaging system from the SNR perspective. An experimental comparison is conducted between a Gaussian beam and plane-wave illumination generated by a novel phase modulation schema using our developed imaging platform. The results indicate that the Gaussian beam produces higher SNR images than plane waves when detecting fluorescent particles in a microchannel. Gaussian beam's higher energy confinement ability enhances the image quality of on-chip fluorescent imaging systems, particularly involving scattering-like medium limitations.Article An ALNS-Based Decision Support System for Scheduling and Routing in Home Healthcare With Lunch Break Constraints(Growing Science, 2025) Ozsakalli, Gokberk; Ozturkoglu, Omer; Qadri, Syed Shah Sultan Mohiuddin; Mohiuddin Qadri, Syed Shah SultanThis study addresses the daily scheduling and routing problem for home healthcare workers while incorporating lunch break requirements. The Home Healthcare Scheduling and Routing Problem is analysed alongside its common constraints, including patient and caregiver time windows, caregiver qualifications, and mandated breaks. To address this, four different variants of an effective Adaptive Large Neighbourhood Search (ALNS) algorithm were developed to provide high-quality solutions. The algorithms demonstrate significant efficiency, solving 30-patient instances optimally within an average of 12 seconds. For scenarios involving 100 patients, they maintained robust performance with a slight increase in computational time of about 54 seconds. Results indicate operational efficiency improvements of up to 36% through optimized travel routes and patient visitation schedules. To translate these findings into practice, a decision support system, the Home Healthcare Decision Support System (HHDSS), was designed to assist administrators by automating the complex task of scheduling and routing of caregivers. Tested using realistic patient data generated from Turkey, the system effectively allocates healthcare resources and improves responsiveness. Overall, the proposed framework shows strong potential as a valuable practical tool for improving the responsiveness and efficiency of home healthcare logistics. (c) 2026 by the authors; licensee Growing Science, CanadaArticle Indoor Soundscape Intervention (ISI) Criteria for Architectural Practice: A Systematic Review With Grounded Theory Analysis(MDPI, 2025) Ercakmak Osma, Ugur Beyza; Dokmeci Yorukoglu, Papatya NurIndoor soundscape is a relatively new and developing field compared to urban soundscape in practice. To address this gap, this study aims to identify the key influencing factors as a first step of the indoor soundscape intervention approach. The study employed a two-phase methodology. Phase one involved a Systematic Review (SR) of the literature, conducted through the PRISMA 2020 guidelines, to collate data on the influencing factors and intervention criteria of the indoor soundscape approach. Searching was conducted using two databases, Web of Science and Scopus. As a result of the search, a total of 29 studies were included in the review. The review included studies addressing the soundscape influencing factors and theoretical frameworks. Studies that did not address these criteria were excluded. Phase two comprised the application of the Grounded Theory (GT) coding process to organize, categorize, and merge the data collected in phase one. As a result of the coding process, three levels of categories were achieved; L1: key concept, L2: overarching category, L3: core category. Four core categories were identified as 'Sound', 'People', 'Building', and 'Environment' by proposing the Indoor Soundscape Intervention (ISI) criteria. The repeatable and updatable nature of the proposed method allows it to be adapted to further studies and different contexts/cases.Article Self-Supervised Learning With BYOL for Non-Alcoholic Fatty Liver Disease Diagnosis Using Ultrasound Imaging(Springer London Ltd, 2025) Buktash, Ali; Gorur, Abdul KadirPurpose:The study aims to evaluate the effectiveness of Bootstrap Your Own Latent (BYOL), a self-supervised learning method for diagnosing NAFLD from ultrasound images using limited labeled data, which represents a novel approach in this domain. Self-supervised learning provides an alternative approach to traditional supervised learning by learning useful representations from unlabeled data, thereby reducing the time and cost required by radiologists to annotate images.Methods:The pre-trained ResNet-50 and ResNet-101 on the labeled ImageNet dataset were used for BYOL pre-training on ultrasound images without relying on labels. The training was conducted using default and custom augmentation, as well as balanced and imbalanced class distribution protocols. The model was then evaluated using linear and fine-tuning protocols with varying percentages of labeled data. The model was trained using three shuffled subsets, each trained 10 times. The custom augmentation set was derived by testing various augmentation settings using 100% and 1% of the labels to enhance feature learning.Results:BYOL with ResNet-101 and using the proposed custom augmentation set achieved average accuracies of 93.44%, 92.29%, and 88.49% using 100%, 10%, and 1% of the training labels across three shuffled datasets. In addition, our proposed method attained an average accuracy of 96.9% using patient-specific leave-one-out cross-validation (LOOCV).Conclusion:BYOL, with the proposed custom augmentation set, can learn effective image representations without relying on a large amount of labeled data, thereby enhancing scalability since unlabeled images are easier to acquire. It surpasses BYOL with default augmentation and training under supervised learning, especially with a low-labeled data regime.Article The Rapprochement Between Turkey and the Eu: The Transformation Process in the Strategic Perceptions From the 1999 Helsinki Summit To the 2003 Iraq War(International Relations Council of Turkey, 2006) Gözen, R.; Gözen, Ramazan; Siyaset Bilimi ve Uluslararası İlişkilerThis article analyses the rapprochement process between Turkey and the EU which has been developing since the 1999 Helsinki Summit and especially in the wake of the US invasion of Iraq. As a result of differing perceptions of Turkey and the EU in the post Cold War, the Turkey-EU membership process had faced a deep "structural" crisis. However, after some important changes in the years from 1999 to 2003, Turkey and the EU rediscovered, and approached each other in such a way that it is incomparable with the past. The basic character of this rapprochement is the strategic transformation in the perceptions.Article Citation - WoS: 1Citation - Scopus: 1The Crime of Genocide in International Law and Underlying Social Structures of the Crime: Rwanda Case(Uluslararasi Iliskiler Konseyi dernegi, 2008) Coban, EbruGenocide is a crime which is defined under international law in the twentieth century and could not come about without the ideological, bureaucratic power of a modern state with its sanctions and modern discourses on identities and modern classifications. With a non-modern picture but with modem techniques of governing Rwanda was a place that genocidal killings occurred and is a place of a breaking case for modem theories. Rwanda has modern state characteristics in terms of monopoly of use of violence, giving orders and providing obedience of its people, surveillance, classification and registration of its people, and keeping discourses. Moreover, Rwandan culture that gives great importance to obedience and Rwandan geography that is so suitable to surveillance become additional factors. In that sense, Rwandan governments could influence to daily life of the people even to the smallest details of anyone. All factors provided a suitable base for the crime of genocide.Article ISAR Imaging of Drone Swarms at 77 GHz(TÜBİTAK Scientific & Technological Research Council of Turkey, 2025) Coruk, Remziye Busra; Kara, Ali; Aydin, ElifThe proliferation of easily available, internet-purchased drones, coupled with the emergence of coordinated drone swarms, poses a significant security threat for airspace. Detecting these swarms is crucial to prevent potential accidents, criminal misuse, and airspace disruptions. This paper proposes a novel inverse synthetic aperture radar (ISAR) imaging technique for high-resolution reconstruction of drone swarms at 77 GHz millimeter wave (mmWave) frequency, offering a valuable tool for military and defense antidrone systems. The key parameters affecting down-range and cross-range resolution (0.05 m), ultimately enabling the generation of detailed ISAR images are discussed. Here, we create diverse scenarios encompassing various swarm formations, sizes, and payload configurations by employing ANSYS simulations. To enhance image quality, different window functions are evaluated, and the Hamming window is selected due to its highest peak signal-to-noise ratio (PSNR) (16.3645) and structural similarity (SSIM) (0.9067) values, ensuring superior noise reduction and structural preservation. The results demonstrate that the effectiveness of high-resolution ISAR imaging in accurately detecting and characterizing drone swarms pave the way for enhanced airspace security measures.Article A Coupled Modelling and Simulation Approach to Electromagnetic Sheet Metal Forming(Taylor & Francis Ltd, 2025) Aslan, Ozgur; Kabakci, Gamze Cakir; Sait, Ferit; Camalan, Caner; Baranoglu, Besim; Bayraktar, Emin; Cakir Kabakci, GamzeThis study presents a coupled numerical and experimental investigation of electromagnetic forming (EMF) for aluminium sheets. A custom simulation framework is developed in ABAQUS/Standard using user-defined material (UMAT) and load (DLOAD) subroutines. The magnetic pressure exerted on the workpiece is computed through a finite difference-based solution of Maxwell's equations and applied to the mechanical solver. The mechanical response of the material is modelled using a strain-rate-sensitive plasticity law calibrated for aluminium 7075-O. Experimental forming trials are performed using a custom-built EMF setup, and the results are compared with numerical predictions to validate the model. The comparison shows strong agreement in deformation profiles, confirming the predictive capability of the proposed simulation strategy. This work offers a reliable computational tool for optimising EMF processes and provides insights into material behaviour under high strain rate electromagnetic loading.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 Low Signature UAVs: Radar Cross Section Analysis, Simulation, and Measurement in X-Band(Springer London Ltd, 2025) Unalir, Dizdar; Yalcinkaya, Bengisu; Aydin, ElifThe increasing prevalence of unmanned aerial vehicles (UAVs) is driving the development of radar systems capable of detecting them. This hampers the deployment of UAVs in military operations. While radar cross section reduction (RCSR) can be a valuable solution, the research on this subject is inadequate. This paper presents an RCSR approach adopting a shaping technique for UAVs, demonstrating the proposed approach's efficacy through simulations and actual experimental measurements performed in X-Band on a four-legged UAV model. Using electromagnetic computational instruments, the shaping is applied to the designed UAV model with parameter-based simulations, the simulated radar cross section (RCS) values are derived, and the comparative analysis of these instruments is conducted. Experimental measurements are performed in laboratory conditions using a vector network analyzer. Actual measurement results are validated by simulative findings with the examination of the influence of frequency, polarization, and aspect angle on RCS. The demonstrated measuring approach allows cost-effective and easily applicable research on RCS in X-Band, a commonly utilized frequency range in military. An average RCSR of 10 dBsm has been accomplished with the presented shaping approach.