Fakülteler / Faculties

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1.5-Tesla Magnetic Resonance-Guided Adaptive Stereotactic Body Radiotherapy for Liver Malignancies
(2023) Onal, C.; Yavas, G.; Yavas, C.; Arslan, G.; Efe, E.; Haberal, M.
A 'Flawless' Constitutional Engineering Project In Turkey: Regime Transformation Through Constitutional Amendments Of 2007, 2010, And 2017
(Başkent Üniversitesi Hukuk Fakültesi, 2024-04-17) Genckaya, Omer Faruk; Dunbay, Seda
A functional legislature is very vital for democratisation. During the time of democratic consolidation, parliament changes from its primary roles of oversight, representation and legislation into 'important public arenas of partisan dispute, of encounters with social topics, of negotiations and of important decision-making'. Populist leaders in parliamentary systems like Turkey recently either led to sui generis presidential systems or transformed them into illiberal democracies by expanding the executive branch's power to amend the constitution, which contradicts the favourable conditions of the third wave of democratisation at the turn of the twenty-first century. By streamlining legislative processes, the Turkish Constitution of 1982 envisaged an empowered executive that would subordinate the parliament. The three constitutional modifications passed after 2007 resulted in de-democratisation, de-parliamentarisation and eventually, a regime change from democratic consolidation to autocracy. The parliamentary debates on these constitutional amendments, which included popular presidential election, judicial reform and the so-called 'Turkish style' presidential governance system, failed to reach a consensus and were marked by an adversarial rather than deliberative approach. Have constitutional reforms made in the name of re-democratisation resulted in de-democratisation, with the legislature entirely crippled, the judiciary reliant and the executive exercising sole authority? This study aims to analyse the impact of three consequential constitutional amendments on democratic backsliding in Turkey, with special reference to the decline of parliament. Parliamentary minutes on the relevant constitutional amendments, procedural changes disabling the parliament from performing its legislative and oversight functions and the actual outcomes of these amendments in terms of executive-legislative relations will be discussed. In conclusion, potentials for strengthening parliament, checks and balances, and re-democratisation will be presented.
A Comprehensive Examination of UV-VIS Spectrophotometric Methods in Pharmaceutical Analysis Between 2015-2023
(Başkent Üniversitesi Eczacılık Fakültesi, 2024-06) Enes, Duygu; Dastan, Kerem; Kaplan, Ozan; Celebier, Mustafa; Dogan, Aysegul
Background: Quality control is a system of validated procedures in which many samples, including active pharmaceutical ingredients and final products, are analyzed using standard or validated analytical methods. Method: Analytical methods used in analyzing active pharmaceutical ingredients or final products in the pharmaceutical industry can be methods registered in pharmacopeias and developed by the company itself. For this reason, published papers related to pharmaceutical analysis attract analysts and researchers' attention. In this study, pharmaceutical analysis and bioanalysis studies carried out between 2015 and 2023 were examined using Google Scholar, and the recent trends were determined for pharmaceutical analysis. Among the published papers performing conventional analytical techniques for pharmaceutical analysis, those applying UV-VIS spectrophotometry method were selected to predict a future perspective in this study. In addition to the data obtained, the current situation of the pharmaceutical industry was considered to correlate with the obtained data for pharmaceutical analysis. Results: The results were presented with comparative tables and summarizing graphs. Interpreting the results allowed us to determine the trends that pharmaceutical analysis studies will lead in the future. This study can be helpful for researchers working on pharmaceutical analysis in both the industry and academia to predict future trends in pharmaceutical analysis. As a result of the literature research covering the dates 2015-2023, 56% of UV-VIS Spectrophotometric methods are used on pharmaceutical dosage forms, 27% are bulk, 16% are pure, 2% are biological materials, and 0.4% are herbal. Made from materials. Of these studies, 28% were conducted in the 200-240 nm range, 27% were conducted in the 240-300 nm range, and only 44% were conducted at >300 nm. Interpreting the results allowed us to determine the trends that pharmaceutical analysis studies will lead in the future. Conclusion: This study can be helpful for researchers working on pharmaceutical analysis in both the industry and academy side to predict future trends for pharmaceutical analysis.
A Comprehensive Investigation Of Biopsychosocial Determinants Influencing Primary Dysmenorrhea Among University Students
(Başkent Üniversitesi Sağlık Bilimleri Fakültesi, 2024-05-17) Yalvac, Canan Oksuz; Topal, Cansu Akdag; Boztepe, Handan
Dysmenorrhea, characterized by pain and related symptoms, significantly impacts women's quality of life in work and education, prompting a comprehensive evaluation of associated factors. The objective of this study was to utilize structural equation modeling (SEM) to analyze and assess the biopsychosocial factors influencing dysmenorrhea among university students. Three hundred and thirty-nine university students were included in this cross-sectional descriptive study. Data were collected using the Participant Information Form, the Beck Anxiety Scale (BAS), the Beck Depression Scale (BDS), the Multidimensional Scale of Perceived Social Support (MSPSS), the Adverse Childhood Experiences Scale (ACES), the Pain Catastrophizing Scale (PCS) and the Visual Analogue Scale (VAS). It was determined that the variables of pain onset (t = 3.24, p < .05) and age at menarche (t = -2.16, p < .05) showed a significant relationship with the model. The variables of the PCS (t = 16.87, p < .001), BDS (t = 3.06, p < .05), and BAS (t = 5.13, p < .001) showed a significant relationship with the model. Social factors in the model were examined, and a family history of dysmenorrhea and the ACES variables did not contribute significantly to the model (p > .05). The study indicates primary dysmenorrhea influenced by biological and psychological factors. Nurses should conduct holistic assessments and provide comprehensive care for affected women.
A Game-Changing Equation During The Etching Of Tuning Forks And Its Verification Through Experiments
(Başkent Üniversitesi Mühendislik Fakültesi, 2024-08-05) Erbas, Kadir Can; Erdogan, Mebrure; Serdaroglu, Dilek cokeliler; Kocum, Ismail Cengiz
Quartz tuning fork (QTF) sensors, characterized by simplicity, low cost, and high-quality factor, represent a significant subset. This study delves into the etching dynamics of QTF systems, crucial for sensor applications like quartz crystal microbalance (QCM). Both theoretical and experimental investigations into QTF etching, via methods like electro-etching for large-scale tuning forks (TF) and low-pressure radio frequency (RF) plasma treatment for QTFs, have been conducted. Surprisingly, post-etching measurements reveal a lower vibrational frequency for both large-scale TFs and QTFs compared to their bare counterparts, unlike QCM sensors. A novel formula correlating this frequency reduction to mass loss has been proposed and validated through lots of experiments. Notably, longitudinal homogeneity emerges as a pivotal factor influencing the accuracy of the proposed formula. In summary, the novel mathematical framework presented herein is poised to catalyze the widespread adoption of low-cost QTFs as mass-sensitive biosensors, marking a significant advancement in the field.
A Plasma Arc-Based Electromechanical System Designed for Microchannel Processing
(Başkent Üniversitesi Mühendislik Fakültesi, 2024-05-31) Akin, Fevzi; Ersoy, Ece; Idil, Deniz; Ozsimitci, Melih; Serdaroglu, Dilek Cokeliler; Ic, Yusuf Tansel; Atalay, Kumru Didem; Kocum, Cengiz; Okat, Kemal
Plasma technology is based on a simple physical principle. When more energy enters the gas, it ionizes and becomes the fourth state of matter, the energy-dense plasma. The studies carried out within the scope of this study were designed to create microchannels on lamellar glass using an improved redesign of the current plasma arc device, which is the main subject of the paper. The created microchannel is examined at the microscale. Experimental analysis was conducted considering the effect of plasma on the effect of microchannel quality. We performed an experimental design study to determine the optimal parameter levels for improving microchannel quality. The predicted results have been validated with the experimental results. An experimental design study provides useful results, such as information about the distance between the probes, pulse duration, and material temperature, which enhances the channel dimensions. The improved device can be utilized effectively to establish microchannel processing in practice.
A Scale For Seventh And Eighth Grade Students' Attitudes Towards Skill-Based Mathematics Questions
(Başkent Üniversitesi Eğitim Fakültesi, 2024-08-10) Erhan, Gonul; Dogan, Oguzhan; Haser, Cigdem
The aim of this study is to develop a theoretically sound, valid, and reliable scale to examine seventh and eighth grade students' attitudes towards so-called skill-based mathematics questions (SBMQ). The sample of the study was 820 seventh and eighth grade students at three different middle schools in Etimesgut District of Ankara Province. A draft item pool was crafted after a detailed literature review and the scale was finalized for the implementation after receiving expert opinions. This version of scale was administered shortly before the national examination which included skill-based questions in the 2022-2023 academic year. Exploratory and confirmatory factor analysis methods were used to examine the construct validity of the scale. The analysis resulted in 16 items in three factors (affective, cognitive, and motivational) which explained 46% of the total variance. Cronbach's alpha and composite reliability scores were above .70 for each factor and whole scale. The results indicated that the Attitudes Towards SBMQ Scale developed for seventh and eighth grade students is valid and reliable.
A Scale For Seventh And Eighth Grade Students' Attitudes Towards Skill-Based Mathematics Questions
(Başkent Üniversitesi Eğitim Fakültesi, 2024-08-10) Erhan, Gonul; Dogan, Oguzhan; Haser, Cigdem
The aim of this study is to develop a theoretically sound, valid, and reliable scale to examine seventh and eighth grade students' attitudes towards so-called skill-based mathematics questions (SBMQ). The sample of the study was 820 seventh and eighth grade students at three different middle schools in Etimesgut District of Ankara Province. A draft item pool was crafted after a detailed literature review and the scale was finalized for the implementation after receiving expert opinions. This version of scale was administered shortly before the national examination which included skill-based questions in the 2022-2023 academic year. Exploratory and confirmatory factor analysis methods were used to examine the construct validity of the scale. The analysis resulted in 16 items in three factors (affective, cognitive, and motivational) which explained 46% of the total variance. Cronbach's alpha and composite reliability scores were above .70 for each factor and whole scale. The results indicated that the Attitudes Towards SBMQ Scale developed for seventh and eighth grade students is valid and reliable.
Accelerated Evaluation of Blocking Flowshop Scheduling With Total Flow Time Criteria Using A Generalized Critical Machine-Based Approach
(Başkent Üniversitesi Mühendislik Fakültesi, 2024-07-10) Han, Yuyan; Wang, Yuting; Pan, Quan-ke; Wang, Ling; Tasgetiren, Fatih
Despite the considerable advances in the research of the blocking flowshop scheduling problem (BFSP), several unresolved challenges persist. Algorithmic complexity presents hurdles. Although the insertion-based method is considered to generate superior solutions, its high computational demand diminishes the efficiency of algorithms, especially within large-scale sequences. The existing accelerated evaluation methods cannot utilize the existing information to quickly calculate the total flow time or the total tardiness time of the changed sequence after the job insertion, but recalculates it from scratch. This does not significantly reduce computational effort and needs to be further improved. In this paper, we delve into the intrinsic features of these challenges, proposing a generalized accelerated critical machine-based evaluation tailored for the total flow time and tardiness criteria of the BFSP with and without sequence-dependent setup times. First, we propose three theorems, one corollary, and their proofs based on the critical machine. Second, we propose the accelerated evaluation procedure based on these theorems to calculate the objectives related to the total flow time. Third, we also extend the proposed accelerated evaluation method to the BFSP with sequence-dependent setup times, aiming to significantly reduce the time complexity. Finally, we conduct four experiments on five well-known benchmarks (a total of 3540 test instances). Through statistical analysis, it becomes evident that our computational efforts have significantly decreased in computing both the total flow time and the total tardiness time. This performance enhancement is superior to the effectiveness of existing acceleration techniques.
An Essential Component Of Antimicrobial Stewardship During The COVID-19 Pandemic In The Intensive Care Unit: De-Escalation
(Başkent Üniversitesi Eczacılık Fakültesi, 2024-05-24) Pehlivanli, Aysel; Ozgun, Cigdem; Sasal-Solmaz, Firdevs Gonca; Yuksel, Didem; Basgut, Bilgen; Ozcelikay, Arif Tanju; Unal, Mustafa Necmettin
Background The antimicrobial de-escalation strategy (ADE) plays a crucial role in antimicrobial stewardship, reducing the likelihood of bacterial resistance. This study aims to evaluate how often the intensive care unit (ICU) used ADE for empirical treatment during COVID-19.Materials Adult ICU patients receiving empirical antimicrobial therapy for bacterial infections were retrospectively studied from September 2020 to December 2021. ADE was defined as (1) discontinuation of an antimicrobial in case of empirical combination therapy or (2) replacement of the antimicrobial to narrow the antimicrobial spectrum within the first 3 days of therapy, according to the test results and clinical picture.Results A total of 99 patients were included in the study. The number of patients who received empirical combined therapy (38.4%) was lower than those who received monotherapy (61.6%). The most preferred monotherapy (45.9%) was piperacillin-tazobactam, while the most preferred in combination treatment (22.7%) was meropenem. Within the first 3 days of admittance to the ICU, 3% of patients underwent ADE for their empirical antimicrobial therapy, 61.6% underwent no change, and 35.4% underwent change other than ADE. Procalcitonin levels were below 2 mu g/L on the third day of treatment in 69.7% of the patients. Culture or culture-antibiogram results of 50.5% of the patients were obtained within the first 3 days of empirical therapy. There was no growth in the culture results of 21 patients (21.2%) during their ICU stay.Conclusion In this study, ADE practice was much lower than expected. In order to reduce the significant differences between theory and reality, clinical, laboratory, and organisational conditions must be objectively assessed along with patient characteristics.
Approximation Theorems Via Pp-statistical Convergence on Weighted Spaces
(Başkent Üniversitesi Mühendislik Fakültesi, 2024-07-08) Yildiz, Sevda; Bayram, Nilay Sahin
In this paper, we obtain some Korovkin type approximation theorems for double sequences of positive linear operators on two-dimensional weighted spaces via statistical type convergence method with respect to power series method. Additionally, we calculate the rate of convergence. As an application, we provide an approximation using the generalization of Gadjiev-Ibragimov operators for P-p-statistical convergence. Our results are meaningful and stronger than those previously given for two-dimensional weighted spaces.
Asymptotic Derivation of Consistent thin Shell Equations for a Fluid-Loaded Elastic Annulus
(Başkent Üniversitesi Mühendislik Fakültesi, 2024-07-08) Yucel, H.; Kaplunov, J.; Ege, N.; Erbas, B.
The classical time-harmonic plane strain problem for a fluid-loaded cylindrical elastic shell is revisited. The results of the low-frequency asymptotic analysis, including explicit formulae for eigenfrequencies, are presented. A refined version of the semi-membrane shell theory is formulated. It is shown that the shell inertia does not affect significantly the lowest eigenfrequencies. It is also demonstrated that the ring stress component has a parabolic linear variation.
Automated Detection of type 1 ROP, type 2 ROP and A-ROP Based on Deep Learning
(Başkent Üniversitesi Mühendislik Fakültesi, 2024-07-02) Yenice, Esay Kiran; Kara, Caner; Erdas, Cagatay Berke
PurposeTo provide automatic detection of Type 1 retinopathy of prematurity (ROP), Type 2 ROP, and A-ROP by deep learning-based analysis of fundus images obtained by clinical examination using convolutional neural networks.Material and methodsA total of 634 fundus images of 317 premature infants born at 23-34 weeks of gestation were evaluated. After image pre-processing, we obtained a rectangular region (ROI). RegNetY002 was used for algorithm training, and stratified 10-fold cross-validation was applied during training to evaluate and standardize our model. The model's performance was reported as accuracy and specificity and described by the receiver operating characteristic (ROC) curve and area under the curve (AUC).ResultsThe model achieved 0.98 accuracy and 0.98 specificity in detecting Type 2 ROP versus Type 1 ROP and A-ROP. On the other hand, as a result of the analysis of ROI regions, the model achieved 0.90 accuracy and 0.95 specificity in detecting Stage 2 ROP versus Stage 3 ROP and 0.91 accuracy and 0.92 specificity in detecting A-ROP versus Type 1 ROP. The AUC scores were 0.98 for Type 2 ROP versus Type 1 ROP and A-ROP, 0.85 for Stage 2 ROP versus Stage 3 ROP, and 0.91 for A-ROP versus Type 1 ROP.ConclusionOur study demonstrated that ROP classification by DL-based analysis of fundus images can be distinguished with high accuracy and specificity. Integrating DL-based artificial intelligence algorithms into clinical practice may reduce the workload of ophthalmologists in the future and provide support in decision-making in the management of ROP.
Autonomous Landing Of A Quadrotor On A Moving Platform Using Motion Capture System
(Başkent Üniversitesi Mühendislik Fakültesi, 2024-06-08) Qassab, Ayman; Khan, Muhammad Umer; Irfanoglu, Bulent
This paper investigates the challenging problem of the autonomous landing of a quadrotor on a moving platform in a non-cooperative environment. The limited sensing ability of quadrotors often hampers their utilization for autonomous landing, especially in GPS-denied areas. The performance of motion capture systems (MCSs) in many application areas is the motivation to utilize them for the autonomous take-off and landing of the quadrotor in this research. An autonomous closed-loop vision-based navigation, tracking, and control system is proposed for quadrotors to perform landing based upon Model Predictive Control (MPC) by utilizing multi-objective functions. The entire process is posed as a constrained tracking problem to minimize energy consumption and ensure smooth maneuvers. The proposed approach is fully autonomous from take-off to landing; whereas, the movements of the landing platform are pre-defined but still unknown to the quadrotor. The landing performance of the quadrotor is tested and evaluated for three different movement patterns: static, square-shaped, and circular-shaped. Through experimental results, the pose error between the quadrotor and the platform is measured and found to be less than 30 cm. Introducing a holistic vision system for quadrotor navigation, tracking, and landing on stationary/moving platforms. Proposing an energy-efficient, smooth, and stable MPC controller validated by Lyapunov analysis. Validating the adept tracking and safe landings of the quadrotor on stationary/moving platforms through three diverse experiments.
Comment on "Management of 80 Sinonasal Undifferentiated Carcinomas. Retrospective Multicentre Study of the French Network of Rare Head and Neck Cancers (REFCOR).
(Başkent Üniversitesi Diş Hekimliği Fakültesi, 2024-06-21) Topkan, Erkan; Somay, Efsun; Selek, Ugur
Comment On Prospective Comparison Of Acute Severe Toxicities Between Smokers And Non-Smokers During Radiotherapy For Head And Neck Cancers
(Başkent Üniversitesi Diş Hekimliği Fakültesi) Topkan, Erkan; Somay, Efsun; Bascil, Sibel; Selek, Ugur
Computer-Aided Colorectal Cancer Diagnosis: Ai-Driven Image Segmentation And Classification
(Başkent Üniversitesi Mühendislik Fakültesi, 2024-05-31) Erdas, Cagatay Berke
Colorectal cancer is an enormous health concern since it is among the most lethal types of malignancy. The manual examination has its limitations, including subjectivity and data overload. To overcome these challenges, computer -aided diagnostic systems focusing on image segmentation and abnormality classi fi cation have been developed. This study presents a two -stage approach for the automatic detection of fi ve types of colorectal abnormalities in addition to a control group: polyp, low-grade intraepithelial neoplasia, high-grade intraepithelial neoplasia, serrated adenoma, adenocarcinoma. In the fi rst stage, UNet3+ was used for image segmentation to locate the anomalies, while in the second stage, the Cross -Attention Multi -Scale Vision Transformer deep learning model was used to predict the type of anomaly after highlighting the anomaly on the raw images. In anomaly segmentation, UNet3+ achieved values of 0.9872, 0.9422, 0.9832, and 0.9560 for Dice Coef fi cient, Jaccard Index, Sensitivity, Speci fi city respectively. In anomaly detection, the Cross -Attention Multi -Scale Vision Transformer model attained a classi fi cation performance of 0.9340, 0.9037, 0.9446, 0.8723, 0.9102, 0.9849 for accuracy, F1 score, precision, recall, Matthews correlation coef fi cient, and speci fi city, respectively. The proposed approach proves its capacity to alleviate the overwhelm of pathologists and enhance the accuracy of colorectal cancer diagnosis by achieving high performance in both the identi fi cation of anomalies and the segmentation of regions.
Deep Generative Models İn Medical İmaging : A Literature Review
(Başkent Üniversitesi Mühendislik Fakültesi, 2024-06-16) Sener, Begum
Deep learning has been used extensively in recent years in numerous studies across many disciplines, including medical imaging. GANs (Generative Adversarial Networks) have started to be widely used in the medical field due to their ability to generate realistic images. Recent research has concentrated on three different deep generative models for improving medical images, and a review of deep learning architectures for data augmentation has been done. In this article, other generative models are emphasized, given the dominance of GANs in the field. Studies have conducted a literature review comparing different deep generative models for medical image data augmentation, without focusing solely on GANs or traditional data augmentation methods. In contrast to variational autoencoders, generative adversarial networks (GANs) are the generative model that is most frequently employed for enhancing medical image data. Recent studies have shown that diffusion models have received more attention in recent years compared to variational autoencoders and GANs for medical image data augmentation. This trend is thought to be related to the fact that many GAN-related research directions have previously been investigated, making it more challenging to advance these architectures' current applications.
Design and Implementation of Drive and Control System for Ultrasonic Motor over Power Line Communication
(ELECTRIC POWER COMPONENTS AND SYSTEMS, 2024-04-20) Daldal, Nihat; Aytar, Oktay; Bekiroglu, Erdal; Bal, Gungor
In this study, remote control application of an ultrasonic motor (USM) has been achieved over the power line communication (PLC) system. Fast, practical, affordable and effective operating mode is essential for the USM. This study aimed to develop an original, efficient, effective and economical method. Drive and control of USM control has been succeeded with the developed PLC control system. A two-phase high-frequency inverter, a power line transmitter, and a power line receiver circuits have been designed to drive and control of the ultrasonic motor. Required measurements are acquired from the power line to select the most suitable communication frequency and coupling circuit impedance for the PLC system. For the communication frequency and impedance value measurements the receiver and the transmitter circuits have been designed. The PLC-controlled system has been tested for different operating conditions of the ultrasonic motor. USM control has been accomplished over the existing power line without using extra cables and interfaces for communication. The obtained results show that the PLC-controlled system is practical, reliable, cost-effective, and feasible for the remote control of the USM. This research contributes a new and essential perspective for the PLC-based remote control studies in addition to the USM drive and control strategies.
Detection and Characterization of Cusp Singularities
(Başkent Üniversitesi Mühendislik Fakültesi, 2024-06-25) Buyuktas, Selin; Karacor, Deniz
Studies on nonlinear analysis of system dynamics have increased in recent years. Since most systems that exist in nature have complex dynamics and therefore exhibit nonlinear behavior; there are various methods and theories developed in this context. Self-similar functions are mathematical functions exhibiting self-similar and scale-invariant behaviors performing fractal structures. Singularities are the basis for producing the self-similar behavior of these functions. Singularity analysis is mainly carried out by using wavelet transform (WT). The cusp singularities are non-oscillating singularities which are characterized by their singularity strength. However, the representation and behavior of this type of singularity differs depending on the sign of the exponent, known as the singularity strength. The cusp singularity functions with negative exponent show irregular behavior progressively different than positively valued functions since the value of the function is undefined at that particular singular point. It is commonly accepted that the singularity strength is studied as Holder exponent of the cusp function, but by definition, the value of this exponent cannot take negative values. We present a new method to estimate the singularity strength of cusp singularities with negative exponent. The developed method is based on analyzing and redistributing the amplitudes of a cusp function with negative exponent by taking the WT. The redistribution of amplitudes over time is achieved by applying curve fitting process to frequency values of the analyzing function.