PubMed İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/8650
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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 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 Beam Moments of Higher-Order Annular Gaussian Beams in Tissue Turbulence(Optica Publishing Group, 2025) Arpali, Serap Altay; Arpali, Caglar; Baykal, YahyaBeam moments of the laser beam at the receiver plane were analyzed using our previously developed formula for the average light intensity of a higher-order annular Gaussian (HOAG) beam in the presence of biological tissue turbulence. HOAG beam moments are examined for the entities of power-in-the-bucket (PIB) and kurtosis across various tissue types such as the upper dermis (human), liver parenchyma (mouse), intestinal epithelium (mouse), and deep dermis (mouse). Moreover, beam moments are explored considering factors like the strength coefficient of the refractive-index fluctuations and the propagation distance. The PIB values for all HOAG beam modes are found to decrease exponentially and steadily, behaving similar to Gaussian beams as tissue length increases. As turbulence intensity increases, higher-order HOAG beam modes transfer optical energy to the receiver more efficiently than the lower order modes. Kurtosis analysis shows that at intermediate distances, the beam energy is distributed toward the edges, while at longer distances, the energy concentration is lower at the edges than at the center. This trend is reflected in increasing kurtosis values across all HOAG modes and tissue types. Considering the changes in PIB and kurtosis, higher-order HOAG modes transfer energy more conservatively within the tissue. Furthermore, the tissue type with the best transfer of optical power was observed to be the deep dermis (mouse). (c) 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, YahyaA 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.Article Citation - WoS: 16Citation - Scopus: 16Comparative Application of Wavelet Approaches To Absorption and Ratio Spectra for the Simultaneous Determination of Diminazene Aceturate and Phenazone in Veterinary Granules for Injection(Govi-verlag Pharmazeutischer verlag Gmbh, 2005) Dinç, E; Baleanu, Dumitru; Kanbur, M; Baleanu, D; MatematikA comparison of two wavelet approaches, Daubechies and reverse Biorthogonal, is described for the quantitative resolution of a binary mixture of diminazene aceturate (DIMA) and phenazone (PHE) in veterinary granules for injection without any chemical separation. These two approaches were specified as db4 (a = 180) and rbior3.7 (a = 125) respectively, after testing the signal analysis parameters for the overlapping absorption spectra and ratio spectra. In the first step db4 (a = 180) was applied to the original absorbance data vector of DIMA and PHE. In the second step rbio3.7 (a = 125) was applied to the ratio spectra data vectors of DIMA using the divisor PHE. The same approach was also subjected to the ratio spectra of PHE using the divisor DIMA. The db4 (a = 180) and rbior3.7 (a = 125) calibration graphs were constructed using the transformation values obtained in the wavelet domain. In the method validation, the wavelet calibration functions were tested using synthetic mixtures and the standard addition technique. The simultaneous quantitative analysis of DIMA and PHE in the commercial veterinary preparation was achieved by the elaborated methods. The assay results were compared with each other and good agreement was observed.Article Citation - WoS: 8Citation - Scopus: 8Dimensions of Agitation Based on the Cohen-Mansfield Agitation Inventory in Patients With Dementia(Turkiye Sinir ve Ruh Sagligi dernegi, 2015) Altunoz, Umut; Baştuğ, Gülbahar; Ozel Kizil, Erguvan Tugba; Kirici, Sevinc; Bastug, Gulbahar; Bicer Kanat, Bilgen; Sakarya, Aysegul; Turan, Engin; Kanat Biçer, Bilgen; PsikolojiObjective: The aim of this study was to investigate the dimensions of agitation in dementia patients using the Turkish version of the Cohen-Mansfield Agitation Inventory (CMAI-T). Materials and Method: The study included 100 patients diagnosed as dementia, according to the DSM-IV-TR. The CMAI-T was administered to the patients' caregivers via face-to-face interviews. The Standardized Mini Mental State Examination (SMMSE) was used to assess cognitive functions. The severity of depression and the functional state of the patients were assessed using the Cornell Scale for Depression in Dementia (CSDD) and the Functional Activities Questionnaire (FAQ). Principal component analysis and varimax rotation were used to determine the factor structure of the CMAI-T. Results: Factor analysis of the CMAI-T indicated a 3-factor structure: physically aggressive agitation, verbal agitation, and physically non-aggressive agitation. In 92% of the patients there >= 1 was agitation behavior during the previous 2 weeks. The CMAI-T total and factor scores were negatively correlated with the SMMSE scores, and positively correlated with the CSDD and the FAQ scores. Conclusions: The CMAI-T yielded 3 factors (physically aggressive agitation, verbal agitation, and physically non-aggressive agitation), which indicated the scale had construct validity Agitation behaviors were associated with cognitive dysfunction, symptoms of depression and general level of functioning. Additional research is necessary to identify the predictors of these dimensions in different dementia samples, and to determine the efficacy of therapeutic interventions.Article Citation - WoS: 13Citation - Scopus: 14Continuous Wavelet Transformation Applied To the Simultaneous Quantitative Analysis of Two-Component Mixtures(Govi-verlag Pharmazeutischer verlag Gmbh, 2004) Dinç, E; Baleanu, Dumitru; Baleanu, D; Üstündag, Ö; Aboul-Enein, HY; MatematikIn this paper we developed a graphical method based on Haar (HA) and Mexican (MEX) one-dimensional continuous wavelet transforms and we applied it to a mixture of hydrochlorothiazide (HCT) and spironolactone (SP) in the presence of strongly overlapping signals. Keeping in mind to obtain an appropriately transformed spectrum, we tested several values of the scaling parameter a and the point number of the analysed spectrum in the concentration range of 2-22 mug/ml for both active compounds. The optimal values of the scale parameters and the corresponding frequencies were found to be a = 32 and 0.031 for HA and a = 30 and 0.008 for MEX corresponding to 400 points. HA and MEX methods based on a zero crossing technique were applied to the analysed signal and their regression lines at the selected points were obtained. The validation of the above methods was carried out by analysing different synthetic mixtures containing HCT and SP. MATLAB 6.5. Software was used for one-dimensional wavelet analysis and the basic concepts about wavelet method were briefly explained. The method developed in this paper is rapid, easy to apply, inexpensive and is suitable for analysing the overlapping signals of compounds in their mixtures without any chemical pre-treatment.Article Citation - WoS: 5Citation - Scopus: 3Intensity Fluctuations of Higher-Order Laser Modes in Jet Engine Exhaust Turbulence(Optica Publishing Group, 2025) Baykal, Yahya KemalIntensity fluctuations quantified by the scintillation index are evaluated in jet engine exhaust turbulence when higher-order laser modes are used in optical wireless communication links. The jet engine exhaust turbulence power spectrum, modified by low-pass and high-pass filters, is employed. Intensity fluctuations are evaluated against the link length, structure constant, wave number (inverse of wavelength) (i.e., against turbulence strength), source size, and jet engine exhaust turbulence parameters. It is found that higher-order laser modes are better at mitigating the scintillations. Jet engine exhaust turbulence parameters are found to affect scintillations substantially. (c) 2025 Optica Publishing Group. All rights, including for text and data mining (TDM), Artificial Intelligence (AI) training, and similar technologies, are reserved.Article Detection and Classification of Femoral Neck Fractures From Plain Pelvic X-Rays Using Deep Learning and Machine Learning Methods(Turkish Assoc Trauma Emergency Surgery, 2025) Sevinc, Huseyin Fatih; Ureten, Kemal; Karadeniz, Talha; Gultekin, Gokhan KorayBackground: Femoral neck fractures are a serious health concern, particularly among the elderly. The aim of this study is to diagnose and classify femoral neck fractures from plain pelvic X-rays using deep learning and machine learning algorithms, and to compare the performance of these methods. Methods: The study was conducted on a total of 598 plain pelvic X-ray images, including 296 patients with femoral neck fractures and 302 individuals without femoral neck fractures. Initially, transfer learning was applied using pre-trained deep learning models: VGG-16, ResNet-50, and MobileNetv2. Results: The pre-trained VGG-16 network demonstrated slightly better performance than ResNet-50 and MobileNetV2 for detecting and classifying femoral neck fractures. Using the VGG-16 model, the following results were obtained: 95.6% accuracy, 95.5% sensitivity, 93.3% specificity, 95.7% precision, 95.5% F1 Score, a Cohen's kappa of 0.91, and the Receiver Operating Characteristic (ROC) curve of 0.99. Subsequently, features extracted from the convolution layers of VGG-16 were classified using common machine learning algorithms. Among these, the k-nearest neighbor (k-NN) algorithm outperformed the others and exceeded the accuracy of the VGG-16 model by 1%. Conclusion: Successful results were obtained using deep learning and machine learning methods for the detection and classification of femoral neck fractures. The model can be further improved through multi-center studies. The proposed model may be especially useful for physicians working in emergency departments and for those not having sufficient experience in evaluating plain pelvic radiographs.