PubMed İndeksli Yayınlar Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/8650

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Citation - WoS: 4
On the Solution of a Parabolic PDE Involving a Gas Flow Through a Semi-Infinite Porous Medium
(Amsterdam, 2021) Pop, Daniel N.; Vrinceanu, N.; Al-Omari, S.; Ouerfelli, N.; Baleanu, D.; Nisar, K. S.; 02.02. Matematik; 02. Fen-Edebiyat Fakültesi; 01. Çankaya Üniversitesi
Taking as start point the parabolic partial differential equation with the respective initial and boundary conditions, the present research focuses onto the flow of a sample of waste-water derived from a standard/conventional dyeing process. In terms of a highly prioritized concern, meaning environment decontamination and protection, in order to remove the dyes from the waste waters, photocatalyses like ZnO or TiO2 nanoparticles were formulated, due to their high surface energy which makes them extremely reactive and attractive. According to the basics of ideal fluid, the key point is the gas flow through an ideal porous pipe consisting of nanoparticles bound one to each other, forming a porous matrix/pipe. The modeling of the gas flow through a porous media is quite valuable because of its importance in investigating the gas-solid processes. The present study is a valid contribution to the existing literature, by developing a nonstandard line method for the partial differential equation, in order to obtain a numerical solution of unsteady flow of gas through nano porous medium. Hence, the physical problem is modeled by a highly nonlinear ordinary differential equation detailed on a semi-finite domain and represents a guidance for several questions originating in the gas flow theory. The findings of this study offered a facile approach to improve an attractive issue related to materials science/chemistry, like synthesis of ZnO or TiO2 nanoparticles forming an ideal nano porous pipe with efficiency in industrial waste waters decontamination.
Comparing Hand-Based and Controller-Based Interactions in Virtual Reality Learning: Effects on Presence and Interaction Performance
(PeerJ Inc, 2025) Saran, Murat; 06.01. Bilgisayar Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
Virtual reality (VR) holds significant promise for enhancing science education by providing immersive and interactive learning experiences. However, the optimal interaction modality within educational VR environments remains an open question. This study investigates the impact of hand-based vs. controller-based interaction on sixth-grade students' sense of presence and interaction performance in a VR science laboratory simulation. Fifty-four sixth-grade students were randomly assigned to either a hand-based interaction group or a controller-based interaction group. Participants completed three interactive science experiments (solar system, electrical circuits, and force/energy) within a virtual laboratory environment designed to mimic their school's physical lab. Presence was assessed using a validated Turkish adaptation of the Presence Questionnaire (PQ), while interaction performance was evaluated using a structured observation form completed by a school teacher. Independent samples t-tests and Mann-Whitney U tests were used to compare the presence and performance scores between the groups. Supplementary analyses explored the effects of gender and prior VR experience. Contrary to expectations, no significant differences were found in either presence (t(49.4) = -0.01, p = 0.992) or interaction performance (t(52) = -1.30, p = 0.199) between the hand-based and controller-based interaction groups. Both interaction modalities yielded comparable levels of self-reported presence and observed performance. However, an unexpected finding emerged regarding performance. A supplementary analysis revealed a significant main effect of gender on performance scores (F(1, 50) = 4.844, p = 0.032), independent of interaction type. Specifically, males demonstrated significantly higher performance than females. This study suggests that, for sixth-grade students engaging in these specific VR science simulations, hand-based and controller-based interactions are equally effective in terms of fostering presence and supporting interaction performance. These findings have practical implications for the design and implementation of VR learning environments, particularly in resource-constrained settings where the reduced maintenance and hygiene concerns associated with hand-based interaction may be advantageous.
Citation - WoS: 6
Citation - Scopus: 6
Modeling the Transmission Dynamics of Middle Eastern Respiratory Syndrome Coronavirus with the Impact of Media Coverage
(Elsevier, 2021) Fatima, BiBi; Alqudah, Manar A.; Zaman, Gul; Jarad, Fahd; Abdeljawad, Thabet; 02.02. Matematik; 02. Fen-Edebiyat Fakültesi; 01. Çankaya Üniversitesi
Middle East respiratory syndrome coronavirus has been persistent in the Middle East region since 2012. In this paper, we propose a deterministic mathematical model to investigate the effect of media coverage on the transmission and control of Middle Eastern respiratory syndrome coronavirus disease. In order to do this we develop model formulation. Basic reproduction number R-0 will be calculated from the model to assess the transmissibility of the (MERS-CoV). We discuss the existence of backward bifurcation for some range of parameters. We also show stability of the model to figure out the stability condition and impact of media coverage. We show a special case of the model for which the endemic equilibrium is globally asymptotically stable. Finally all the theoretical results will be verified with the help of numerical simulation for easy understanding.
Citation - WoS: 16
Citation - Scopus: 16
Comparative 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; 6981; 36107; Matematik; 02.02. Matematik; 02. Fen-Edebiyat Fakültesi; 01. Çankaya Üniversitesi
A 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.
Citation - WoS: 8
Citation - Scopus: 8
Dimensions 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; 48292; Psikoloji; 02.04. Psikoloji; 02. Fen-Edebiyat Fakültesi; 01. Çankaya Üniversitesi
Objective: 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.
Citation - WoS: 13
Citation - Scopus: 14
Continuous 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; 56389; Matematik; 02.02. Matematik; 02. Fen-Edebiyat Fakültesi; 01. Çankaya Üniversitesi
In 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.
Intensity Fluctuations of Higher-Order Laser Modes in Jet Engine Exhaust Turbulence
(Optica Publishing Group, 2025) Baykal, Yahya Kemal; 06.03. Elektrik-Elektronik Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
Intensity 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.
Developing and Validating a Rubric-Based Approach to Quality Assurance in Turkish Higher Education
(Pergamon-Elsevier Science Ltd, 2025) Akkoyunlu, Buket; Bardakci, Salih; Yildirim, Sibel Aksu; Avsaroglu, M. Dilek; Uludag, Gonca; Kocer, Ayhan; Elmas, Muzaffer; 09.01. Ortak Dersler Bölümü; 09. Rektörlük; 01. Çankaya Üniversitesi
This study, initiated by the Turkish Higher Education Quality Council (THEQC), develops and validates a rubricbased approach for evaluating institutional quality assurance (QA) processes within the Turkish higher education ecosystem. Effective quality assurance (QA) in higher education requires evaluation tools that are methodologically robust, responsive to institutional needs, and aligned with international benchmarks. A rubric-based approach offers a structured and transparent framework for consistent assessments. The rubric was created through an iterative, evidence-based process incorporating expert feedback, international benchmarks, site visits, and prior research. It consists of 22 main criteria across four key domains-Leadership, Governance and Quality; Learning and Teaching; Research and Development; and Service to Society-subdivided into 46 sub-criteria, each assessed on a five-point maturity scale. The validity and reliability of the rubric were rigorously examined. Content validity was established through evaluations by 10 QA professionals, addressing four key dimensions: relevance, alignment with the intended domain, appropriateness for the target audience, and clarity of language. Construct and criterion validity were assessed through consistency checks and usability analyses, with data collected from 252 external evaluators across 57 higher education institutions. Additionally, 360-degree feedback was gathered from both external evaluation teams and the institutions involved in the evaluation process. Results: demonstrate strong content validity (Lawshe coefficient =1.00, p < .05), high interrater consistency, and strong usability across various evaluator groups. Further evaluation confirmed the rubric's applicability and robustness across diverse institutional contexts. This study concludes that the developed rubric is a reliable and valid tool for enhancing and evaluating quality assurance practices in higher education.
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 Koray; 06.09. Yazılım Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
Background: 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.
Citation - WoS: 1
Citation - Scopus: 1
Propagation of Higher-Order Annular Gaussian Beams in Biological Tissues
(Optica Publishing Group, 2025) Arpali, Serap Altay; Baykal, Yahya Kemal; 06.02. Elektronik ve Haberleşme Mühendisliği; 06.03. Elektrik-Elektronik Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
The propagation characteristics of a higher-order annular Gaussian (HOAG) beam in biological tissue turbulence are investigated. Average intensity at the receiver plane is found when the HOAG source field is used as excitation. The effects of the HOAG beam on different tissue types of the upper dermis (human), liver parenchyma (mouse), intestinal epithelium (mouse), and deep dermis (mouse) are studied. Variations of the average intensity versus the source and medium parameters such as the strength coefficient of the refractive-index fluctuations, propagation distance, wavelength, and beam size are presented. The results show that all modes of the HOAG beam can successively transmit beam energy at different levels of turbulence for all tissue types. At the same turbulence strength, HOAG beams having larger mode numbers transmit higher intensity to receivers than the modes with smaller mode orders, which is valid for all the examined tissue types. As the strength of tissue turbulence increases, the HOAG beam slowly turns into a pure Gaussian beam. For the different tissue types, the highest beam intensity at the receiver was observed for the deep dermis (mouse) tissue type. Despite the change in wavelength, refractive-index fluctuations, and source beam size, the highest beam transmission through the tissue in a turbulent environment was also observed for this same tissue type. This research may be useful in understanding the fundamentals of lighttissue interaction of HOAG laser beams, which may improve noninvasive disease detection and therapy methods through tissue in biophotonic technologies. (c) 2025 Optica Publishing Group. All rights, including for text and data mining (TDM), Artificial Intelligence (AI) training, and similar technologies, are reserved.
Life Cycle Assessment of Geopolymer Materials Utilizing Construction and Demolition Waste
(Academic Press Inc Elsevier Science, 2025) Unsal, Zeynep; Ekinci, Mehmet Ozkan; Ilcan, Huseyin; Sahin, Oguzhan; Selcuk, Seda; Sahmaran, Mustafa; 06.05. İnşaat Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
This study assessed the environmental impacts of construction and demolition waste (CDW)-based geopolymers. For analysis, the cradle-to-gate system boundary was established. Two different geopolymer mixtures were evaluated: one composed entirely of CDW-based precursors-(CDW100), and another incorporating supplementary cementitious materials-(SCMs) as a 20 % replacement of CDW-based precursors-(CDW80SCM20). Raw materials were sourced from a diverse range of demolition waste. NaOH and Ca(OH)2 were employed as activators. Additionally, a cementitious mixture with comparable strength was included in the analysis as a benchmark for comparison with the geopolymers. The results of the impact analyses revealed that CDW80SCM20 had a greater environmental impact across various categories compared to CDW100. The relatively higher environmental impacts of the CDW80SCM20 mixture are largely attributed to the transport-related environmental burdens associated with the inclusion of SCMs. The largest differences were for land occupation and global warming, at 30.8 % and 16.9 %, respectively. Moreover, the results indicated that the environmental impacts of the CDW-based mortars were significantly lower than those of the cementitious system, with the exception of aquatic eutrophication and ozone layer depletion. The increase in ozone layer depletion is mainly associated with the production of NaOH via the chlor-alkali process, which contributes to emissions affecting stratospheric ozone. The advantages of geopolymers in terms of environmental impact made it possible to reduce the effects of global warming by 48.1 %, aquatic acidification by 22.1 %, land occupation by 45.2 %, and nonrenewable energy consumption by 1.83 %. However, aquatic eutrophication and ozone layer depletion were found to be higher compared to cementitious mortar.
Interfacial Behavior and Diffusion Mechanisms of Bni-2 Brazing on Titanium Alloy: Experimental and Molecular Dynamics Insights
(Springer, 2025) Goynuk, Tansu; Esen, Ziya; Karakaya, Ishak; 09.01. Ortak Dersler Bölümü; 09. Rektörlük; 01. Çankaya Üniversitesi
ContextJoining titanium alloys, particularly Ti-6Al-4V, is crucial in aerospace applications where reliable, high-performance joints are needed. Brazing offers an effective solution, enabling the joining of dissimilar materials without melting the base metals. However, optimizing the wetting and diffusion behavior of filler metals remains a challenge. This study investigates the high-temperature interaction between BNi-2 filler alloy and Ti-6Al-4V. Boron, the primary melting point depressant in BNi-2, was examined due to its small atomic size and interstitial diffusion mechanism. Elevated temperatures led to improved wetting, reflected by decreased contact angles. Both wetting angles and boron diffusion coefficients were obtained through molecular dynamics simulations and experimental measurements, showing reasonable correlation. These results provide valuable insight into interfacial mechanisms and support further optimization of brazing parameters.MethodsMolecular dynamics simulations were performed using LAMMPS to analyze the temperature-dependent wetting behavior of molten BNi-2 on Ti-6Al-4V and track atomic-scale diffusion. Initial atomic configurations were modeled and simulated under various conditions. Trajectory data were analyzed using OVITO for structural evolution. Boron diffusion was evaluated by calculating mean square displacement from LAMMPS outputs. These values were used to derive diffusion coefficients and activation energies. Parallel experiments were conducted to assess wetting angles and diffusion behavior, and simulation results were compared with experimental data. The consistency between both approaches highlights the reliability of the modeling framework in capturing essential mechanisms during the brazing process.
Citation - WoS: 11
The Role of Positive Relationship Events in Romantic Attachment Avoidance
(Amer Psychological Assoc, 2023) Bayraktaroglu, Deniz; Gunaydin, Gul; Selcuk, Emre; Besken, Miri; Karakitapoglu-Aygun, Zahide; 03.02. Halkla İlişkiler ve Reklamcılık; 03. İktisadi ve İdari Birimler Fakültesi; 01. Çankaya Üniversitesi
Motivated by the Attachment Security Enhancement Model (Arriaga et al., 2018), the present research investigated the associations between positive relationship experiences and romantic attachment avoidance in three dyadic studies that combined multiple methods, including daily diaries, laboratory observations, and longitudinal follow-ups. Frequency of daily positive relationship events (but not external positive events) during a 21-day diary period predicted declines in romantic attachment avoidance (but not anxiety) from pre- to post-diary in fledgling couples (Study 1) and newlyweds (Study 2). Video-recorded discussions of fledgling couples' shared positive experiences revealed that behaviors validating the relationship (but not simply showing conversational interest) predicted lagged declines in romantic attachment avoidance (but not anxiety) over 1 month (Study 3). The associations were mediated by positive affect during the diary period in Studies 1 and 2, and by changes in positive affect from pre- to post-discussion in Study 3. Positive relationship experiences did not significantly interact with time in predicting romantic avoidance over a 1-year follow-up with quarterly assessments of attachment orientations in Study 1, over an 8-month follow-up with monthly assessments in Study 2, or over a 2-month follow-up with monthly assessments in Study 3. Altogether, these studies provide one of the most comprehensive tests of how positive relationship experiences in nondistressing contexts are linked to romantic attachment.
Citation - WoS: 1
Citation - Scopus: 1
Convolutional Neural Network-Based Deep Learning for Landslide Susceptibility Mapping in the Bakhtegan Watershed
(Nature Portfolio, 2025) Feng, Li; Zhang, Maosheng; Mao, Yimin; Liu, Hao; Yang, Chuanbo; Dong, Ying; Nanehkaran, Yaser A.; 01. Çankaya Üniversitesi
Landslides pose a significant threat to infrastructure, ecosystems, and human safety, necessitating accurate and efficient susceptibility assessment methods. Traditional models often struggle to capture the complex spatial dependencies and interactions between geological and environmental factors. To address this gap, this study employs a deep learning approach, utilizing a convolutional neural network (CNN) for high-precision landslide susceptibility mapping in the Bakhtegan watershed, southwestern Iran. A comprehensive landslide inventory was compiled using 235 documented landslide locations, validated through remote sensing and field surveys. An equal number of non-landslide locations were systematically selected to ensure balanced model training. Fifteen key conditioning factors-including topographical, geological, hydrological, and climatological variables-were incorporated into the model. While traditional statistical methods often fail to extract spatial hierarchies, the CNN model effectively processes multi-dimensional geospatial data, learning intricate patterns influencing slope instability. The CNN model outperformed other classification approaches, achieving an accuracy of 95.76% and a precision of 95.11%. Additionally, error metrics confirmed its reliability, with a mean absolute error (MAE) of 0.11864, mean squared error (MSE) of 0.18796, and root mean squared error (RMSE) of 0.18632. The results indicate that the northern and northeastern regions of the Bakhtegan watershed are highly susceptible to landslides, highlighting areas where proactive mitigation strategies are crucial. This study demonstrates that deep learning, particularly CNNs, offers a powerful and scalable solution for landslide susceptibility assessment. The findings provide valuable insights for urban planners, engineers, and policymakers to implement effective risk reduction strategies and enhance resilience in landslide-prone regions.
Unveiling the Strain Uniformity Challenge: Design and Evaluation of a Pdms Membrane for Precise Mechanobiology Studies
(Taylor & Francis Ltd, 2025) Duz, Nilufer; Gulsum, Yasin; Odeibat, Waleed; Uyanik, Ismail; Akar, Samet; Dincer, Pervin; 06.06. Makine Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
Mechanotransduction and mechanosensing enable cells to respond to mechanical stimuli, essential in various physiological functions. Specialized cell stretching devices use stretchable, transparent, and biocompatible elastomeric membranes to study these responses. However, achieving strain uniformity is a key challenge, affecting data accuracy and reliability. This study designed a polydimethylsiloxane (PDMS) membrane with optimized uniformity for electromechanical cell stretching. Finite element analysis optimized membrane size and shape, achieving a 90% strain uniformity index-a 233% improvement over commercial membranes. By tailoring material properties like cross-linker ratio and curing time, membrane failure issues were resolved, enhancing applications in tissue engineering and mechanobiology research.
Citation - WoS: 3
Citation - Scopus: 3
A Comparison of Crystal Phenol Treatment, Midline Primary Closure and Limberg Flap Reconstruction Methods in Female Patients With Primary Pilonidal Sinus Disease
(Edizioni Luigi Pozzi, 2021) Kanlioz, Murat; Uyanikoglu, Hacer; Ekici, Ugur; Karatas, Turgay; Tatli, Faik; 01. Çankaya Üniversitesi
Pilonidal sinus disease (PSD) is a chronic problem often occurs in healthy hirsute men, however, women may also be affected. A range of conservative techniques to surgical flaps have been used to treat this condition. Currently, midline primary closure (MPC) is considered the standard of therapy; however, no statistically significant difference has been noted between primary versus secondary (Karydakis flap or Limberg flap) closure. Recently, flap reconstruction methods have been applied and superiority of these methods have been shown. Treatment methods should be employed to the individual, taking into account recurrence and complication rates of the method, recovery time, patients' preference and surgeon's skill.
Citation - WoS: 1
Citation - Scopus: 5
Fast Binary Logistic Regression
(Peerj inc, 2025) Saran, Nurdan Ayse; Nar, Fatih; 06.01. Bilgisayar Mühendisliği; 02.02. Matematik; 02. Fen-Edebiyat Fakültesi; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
This study presents a novel numerical approach that improves the training efficiency of binary logistic regression, a popular statistical model in the machine learning community. Our method achieves training times an order of magnitude faster than traditional logistic regression by employing a novel Soft-Plus approximation, which enables reformulation of logistic regression parameter estimation into matrix-vector form. We also adopt the L-f-norm penalty, which allows using fractional norms, including the L-2-norm, L-1-norm, and L-0-norm, to regularize the model parameters. We put L-f-norm formulation in matrix-vector form, providing flexibility to include or exclude penalization of the intercept term when applying regularization. Furthermore, to address the common problem of collinear features, we apply singular value decomposition (SVD), resulting in a low-rank representation commonly used to reduce computational complexity while preserving essential features and mitigating noise. Moreover, our approach incorporates a randomized SVD alongside a newly developed SVD with row reduction (SVD-RR) method, which aims to manage datasets with many rows and features efficiently. This computational efficiency is crucial in developing a generalized model that requires repeated training over various parameters to balance bias and variance. We also demonstrate the effectiveness of our fast binary logistic regression (FBLR) method on various datasets from the OpenML repository in addition to synthetic datasets.
Citation - WoS: 1
Citation - Scopus: 1
Evaluation of the Effects of Avatar on Learning Temporomandibular Joint in a Metaverse-Based Training
(John Wiley and Sons Inc, 2024) Basmaci, Fulya; Bulut, Ali Can; Ozcelik, Erol; Ekici, Saliha Zerdali; Kilicarslan, Mehmet Ali; Cagiltay, Nergiz Ercil; 02.04. Psikoloji; 06.09. Yazılım Mühendisliği; 02. Fen-Edebiyat Fakültesi; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
PurposeAvatars, representing users in the digital world, can influence users' behavior and attitudes. This study evaluates the impact of representing dental students receiving temporomandibular joint (TMJ) education in the metaverse via an anonymous or identified avatar.MethodsParticipants included 80 dental students in their fourth and fifth years of study. They were randomly assigned to either the avatar group (identified avatar) or the control group (anonymous avatar). Prior to training, participants completed a demographic questionnaire and a pretraining knowledge assessment. TMJ training was conducted in the metaverse for both groups. Pre- and post-training assessments included the Spielberger State-Trait Anxiety Inventory and a shyness scale to ensure group comparability. A post-test consisting of five questions was administered to both groups after 2 weeks of training.ResultsThere were no significant differences in pretraining scores for prior knowledge (p = 0.67), trait anxiety (p = 0.28), state anxiety (p = 0.92), or shyness (p = 0.42) between the avatar and control groups, indicating comparability at baseline. Post-training analysis revealed significantly higher post-test scores in the avatar group (median = 80) compared to the control group (median = 60) (p = 0.03).ConclusionsMetaverse environments offer various benefits for students, educators, and educational institutions in health education programs. Representing learners and their identities in training environments can enhance learning outcomes.
Citation - WoS: 1
Citation - Scopus: 1
Structure Functions for Optical Waves in a Complex Medium of Turbulent Biological Tissues
(Optica Publishing Group, 2022) Ata, Yalcin; Baykal, Yahya; Gokce, Muhsin caner; 06.02. Elektronik ve Haberleşme Mühendisliği; 06.03. Elektrik-Elektronik Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
Although optical wave propagation is investigated based on the absorption and scattering in biological tissues, the turbulence effect can also not be overlooked. Here, the closed-form expressions of the wave structure func-tion (WSF) and phase structure function (PSF) of plane and spherical waves propagating in biological tissue are obtained to help with future research on imaging, intensity, and coherency in turbulent biological tissues. This paper presents the effect of turbulent biological tissue on optical wave propagation to give a perception of the per-formance of biomedical systems that use optical technologies. The behavior of optical waves in different types of turbulent biological tissues such as a liver parenchyma (mouse), an intestinal epithelium (mouse), a deep dermis (mouse), and an upper dermis (human) are investigated and compared. It is observed that turbulence becomes more effective with an increase in the characteristic length of heterogeneity, propagation distance, and the strength of the refractive index fluctuations. However, an increase in the fractal dimension, wavelength, and small length scale factor has a smaller turbulence effect on the propagating optical wave. We envision that our results may be used to interpret the performance of optical medical systems operating in turbulent biological tissues.(c) 2022 Optica Publishing Group
Citation - WoS: 1
Citation - Scopus: 1
Field Correlations of Multimode Optical Beams in Underwater Turbulence
(Optica Publishing Group, 2024) Baykal, Yahya; Gokce, Muhsin C.; Ata, Yalcin; Gercekcioglu, Hamza; 06.02. Elektronik ve Haberleşme Mühendisliği; 06.03. Elektrik-Elektronik Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
For multimode optical beams, field correlations at the receiver plane are found in underwater turbulence. Field correlations of single high order beams in underwater turbulence are special cases of our formulation. Variations of field correlations against the underwater turbulence parameters and the diagonal length from various receiver points are examined for different multimode and single high order beams. Stronger underwater turbulence is found to reduce the field correlations of multimode and single high order optical beams. The results will be of help in heterodyne detection analysis and fiber coupling efficiency in an underwater medium experiencing turbulence. (c) 2024 Optica Publishing Group

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