Scopus İndeksli Yayınlar Koleksiyonu

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  • Article
    Comparison of the Unmodified Rytov Method and the Modified Rytov Method in Obtaining Scintillations in Various Strongly Turbulent Media
    (Optica Publishing Group (Formerly OSA), 2026) Baykal, Y.
    The scintillation index as evaluated by the unmodified (classical) Rytov method solution for weak turbulence and evaluated by the modified or the extended Rytov method solution for strong turbulence is compared in different turbulent media, such as non-Kolmogorov atmospheric, non-Kolmogorov jet engine exhaust, marine atmospheric, and oceanic turbulences. When the scintillations are evaluated against the turbulence strength for various non-Kolmogorov power law and source sizes, the distinction between the modified Rytov and the unmodified Rytov method solutions, as the strength of turbulence increases, is clearly observed in all the turbulent media. This distinction is emphasized when the comparison is made at larger power law and source sizes. The results in this paper will be helpful in optical wireless communication system performance evaluations. © 2025 Optica Publishing Group.
  • Article
    Field Correlations of a Gaussian Vortex Laser Beam in Vertical Turbulent Oceanic Links
    (Optica Publishing Group (Formerly OSA), 2026) Gerçekcioǧlu, H.; Baykal, Y.
    Utilizing the extended Huygens–Fresnel principle, field correlations of a Gaussian vortex beam propagating in the vertical turbulent oceanic link are examined analytically and evaluated by simulation in the Atlantic Ocean at low- and mid-latitude and high-latitude summer. Our formulation is based on the coherence length of a spherical wave operating at the depth range between 3000 and 3500 m. Variations in the rate of dissipation of turbulent kinetic energy per unit mass of fluid ε, the rate of dissipation of the mean-squared temperature χT, and the ratio of temperature to salinity contributions to the refractive index spectrum ω are taken into account at these depths in the underwater turbulent medium. The field correlation obtained using the coherence length found with the help of the depth-dependent power spectrum is expressed in detail. When the topological charge is selected considering the source size and propagation distance, it is seen that the normalized field correlation of the Gaussian vortex beam gives better results as compared to Gaussian beams. © 2025 Optica Publishing Group. All rights, including for text and data mining (TDM), Artificial Intelligence (AI) training, and similar technologies, are reserved.
  • Article
    Beam Shaping on a Fluorescent On-Chip Imaging System
    (IOP Publishing Ltd, 2026) Arpali, Caglar; Arpali, Serap Altay
    The 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
    Improving Last-Mile Delivery in Humanitarian Logistics by Solving a Two-Echelon Routing Problem with Portering and Infrastructure Disruptions
    (Springer India, 2026) Mutlu, Ismail Nurullah; Togrul, Ergul Kisa; Kazanc, H. Cansin Uzgoren; Kilic, Kaan; Soysal, Mehmet; Uzgören Kazanç, H. Cansın; Kısa Toğrul, Ergül
    Over time, catastrophes have increasingly caused significant material and human losses. Effective logistics management in humanitarian aid is crucial to minimizing these impacts. Infrastructure damage from disasters introduces uncertainties that must be considered when routing trucks for relief item delivery. This study proposes a Mixed Integer Programming model for the Two-Echelon Vehicle Routing Problem in Humanitarian Aid Logistics (2E-VRP-HAL) to minimize total travel time. An earthquake scenario in Kartal, Istanbul is used to demonstrate the model's accuracy and applicability while accounting for road closures. A diverse fleet, including trucks and pedestrians, addresses delivery challenges, with handover stations enabling access to unreachable areas. To address larger problem instances, a set partitioning approach is used to cluster demand points, followed by a MIP-based local search heuristic to refine the results. Numerical analysis shows up to 15.83% improvement in medium-sized instances and feasible results for larger cases where the model struggles. These findings highlight the potential of proposed decision support methods.
  • Article
    Citation - Scopus: 1
    Randomised Comparison Between Navigation and Non-Navigation Camera Control Performance in a Surgical Simulation Task Using a Haptic Device Interface
    (Wolters Kluwer Medknow Publications, 2026) Cagiltay, Nergiz Ercil; Topalli, Damla; Tuner, Emre; Berker, Mustafa
    Introduction:Navigation skills for controlling the camera in the surgical field are critical for many minimally invasive surgery (MIS) procedures. Currently, endoscopes lack integrated navigation aids, making camera control a challenging task. This experimental study aims to investigate the effect of navigation guidance on the performance of beginners.Patients and Methods:A custom computer-based simulation environment was developed for this study, featuring two conditions - one with navigation guidance and one without - focussed on a camera-cleaning task. Participants (64 beginners) were randomly assigned to one of these groups and used two haptic devices to simulate the endoscope and surgical tools.Results:Participants in the guided condition performed significantly better than those in the unguided condition. Notably, female participants completed the task in significantly less time under the guided condition compared to the unguided one.Conclusion:These findings suggest that incorporating navigation aids into endoscope interfaces could improve user performance, especially for beginners. Medical device manufacturers should consider adding navigation features to enhance usability. In addition, simulation-based instructional systems should integrate navigation aids to better support surgical training.
  • 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 Sultan
    This 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, Canada
  • Article
    Importance of Zoning for Vertical Circulation Planning of Densely Populated Buildings: A Simulation Based Approach for Elevator Traffic Analyses
    (Gazi Univ, 2025) Deligoz, Dostcan; Harputlugil, Timucin
    Elevator systems are essential in multi-story buildings, affecting circulation, travel time, and user comfort. Traditional design methods, based on mathematical calculations, provide initial estimates of elevator numbers and capacities by considering basic operational criteria. However, these methods cannot fully capture dynamic passenger flows and temporal variations in demand. Dynamic simulation-based elevator traffic analysis, on the other hand, allows for more comprehensive evaluation of elevator operations and enables testing of alternative zoning scenarios. In this study, a dynamic simulation-based analysis is applied as a case study for a hospital outpatient building. Different zoning strategies are implemented for elevator groups to evaluate their effect on system performance. Performance criteria, including Average Waiting Time (AWT), Average Time To Destination (ATTD), and Interval (INT), are assessed across different zoning scenarios and compared with values commonly reported in the literature. The results highlight the potential of zoning to improve elevator performance, including passenger handling, waiting times, and travel efficiency. Especially in buildings where physical modifications are difficult, the combination of simulation-based analysis and carefully designed zoning strategies can reveal the potential for enhancing operational performance and optimizing elevator efficiency within existing physical constraints.
  • Article
    Citation - WoS: 1
    Citation - Scopus: 1
    Process Simulation of Pseudo-Static Seismic Loading Effects on Buried Pipelines: Finite Element Insights Using RS2 and RS3
    (MDPI, 2025) Alrubaye, Maryam; Sengor, Mahmut; Almusawi, Ali
    Buried pipelines represent critical lifeline infrastructure whose seismic performance is governed by complex soil-structure interaction mechanisms. In this study, a process-based numerical framework is developed to evaluate the pseudo-static seismic response of buried steel pipelines installed within a trench. A comprehensive parametric analysis is conducted using the finite-element software Rocscience RS2 (version 11.027) to examine the influence of burial depth, pipeline diameter, slope angle, groundwater level, soil type, and permanent ground deformation. The seismic loading was represented using a pseudo-static horizontal acceleration, which approximates permanent ground deformation rather than full dynamic wave propagation. Therefore, the results represent simplified lateral seismic demand and not the complete dynamic soil-structure interaction response. To verify the reliability of the 2D plane-strain formulation, a representative configuration is re-simulated using the fully three-dimensional platform Rocscience RS3. The comparison demonstrates excellent agreement in shear forces, horizontal displacements, and cross-sectional distortion patterns, confirming that RS2 accurately reproduces the dominant load-transfer and deformation mechanisms observed in three-dimensional (3D) models. Results show that deeper burial and stiffer soils increase shear demand, while higher groundwater levels and larger permanent ground deformation intensify lateral displacement and cross-sectional distortion. The combined 2D-3D evaluation establishes a validated computational process for predicting the behavior of buried pipelines under a pseudo-static lateral load and provides a robust basis for engineering design and hazard mitigation. The findings contribute to improving the seismic resilience of lifeline infrastructure and offer a validated framework for future numerical investigations of soil-pipeline interaction.
  • Article
    Field Correlations in Jet Engine Exhaust Turbulence
    (Optica Publishing Group (Formerly OSA), 2026) Baykal, Y.
    Field correlations of collimated Gaussian beams are formulated and examined in jet engine exhaust turbulence. Variations of the field correlations are evaluated against the changes in the parameters of the wireless optical communication link and the jet engine exhaust turbulence. It is found that for all the link and turbulence parameters of interest, as the diagonal distance at the receiver plane increases, the field correlation decreases. Also, at the same diagonal distance from the receiver plane, field correlations tend to become smaller as the receiver points are at a larger distance from the receiver origin, at a smaller source size, wavelength, and inner scale values of jet engine exhaust turbulence. On the other hand, field correlations have a tendency to attain larger values at smaller link length, structure constant, amplitude coefficient for the additional high frequency spectrum area, outer scale of inhomogeneity, and the outer scale values of jet engine exhaust turbulence. © 2025 Optica Publishing Group. All rights, including for text and data mining (TDM), Artificial Intelligence (AI) training, and similar technologies, are reserved.
  • Article
    Laser Ablation Device with a Closed-Loop Control System
    (Optica Publishing Group, 2025) Beldek, Ulas; Erdogan, Kubra; Arpali, Caglar; Baykal, Yahya
    A laser ablation device with real-time beam power control is designed and implemented. This platform regulates the intensity of the laser beam by continuously measuring its intensity distribution. The quality of the ablation process is optimized through a closed-loop control system that uses a rule-based decision-making approach. The controller generates a starting signal for both the laser power and the motors based on the estimated quality of the ablation. The effects of laser power and light intensity on the formation of microchannels in polymethylmethacrylate material were investigated using the laser beam. The quality of the ablation geometry was assessed through image processing and inspection under a scanning electron microscope. The generated microchannels were analyzed in terms of roughness and residual thermal stress. A comparison of the experimental results with theoretical calculations and simulations revealed that the closed-loop control of laser beam power is effective for material etching and for creating smoother channel profiles. (c) 2025 Optica Publishing Group. All rights, including for text and data mining (TDM), Artificial Intelligence (AI) training, and similar technologies, are reserved.