Yazar "Kavuran, Gurkan" seçeneğine göre listele

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    A theoretical demonstration for reinforcement learning of PI control dynamics for optimal speed control of DC motors by using Twin Delay Deep Deterministic Policy Gradient Algorithm
    (Pergamon-Elsevier Science Ltd, 2023) Tufenkci, Sevilay; Alagoz, Baris Baykant; Kavuran, Gurkan; Yeroglu, Celaleddin; Herencsar, Norbert; Mahata, Shibendu
    To benefit from the advantages of Reinforcement Learning (RL) in industrial control applications, RL methods can be used for optimal tuning of the classical controllers based on the simulation scenarios of operating con-ditions. In this study, the Twin Delay Deep Deterministic (TD3) policy gradient method, which is an effective actor-critic RL strategy, is implemented to learn optimal Proportional Integral (PI) controller dynamics from a Direct Current (DC) motor speed control simulation environment. For this purpose, the PI controller dynamics are introduced to the actor-network by using the PI-based observer states from the control simulation envi-ronment. A suitable Simulink simulation environment is adapted to perform the training process of the TD3 algorithm. The actor-network learns the optimal PI controller dynamics by using the reward mechanism that implements the minimization of the optimal control objective function. A setpoint filter is used to describe the desired setpoint response, and step disturbance signals with random amplitude are incorporated in the simu-lation environment to improve disturbance rejection control skills with the help of experience based learning in the designed control simulation environment. When the training task is completed, the optimal PI controller coefficients are obtained from the weight coefficients of the actor-network. The performance of the optimal PI dynamics, which were learned by using the TD3 algorithm and Deep Deterministic Policy Gradient algorithm, are compared. Moreover, control performance improvement of this RL based PI controller tuning method (RL-PI) is demonstrated relative to performances of both integer and fractional order PI controllers that were tuned by using several popular metaheuristic optimization algorithms such as Genetic Algorithm, Particle Swarm Opti-mization, Grey Wolf Optimization and Differential Evolution.
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    AI-supported decision framework for sustainable reconstruction: Case study • on TOKI housing after the 2023 Kahramanmaras,earthquake
    (Pergamon-Elsevier Science Ltd, 2026) Kavuran, Gurkan; Yaman, Gonca Ozer; Basarir, Bahar; Dogan, Ebru; Ince, Beyzanur; Dagteke, Gokce
    This study presents a hybrid analytical and machine learning-based framework to evaluate and classify the electricity performance of standardized TOKI center dot housing units planned for reconstruction in the aftermath of the February 6, 2023, Kahramanmaras,earthquakes. While a standardized building model was analyzed using dynamic energy simulation (DesignBuilder) for 11 affected provinces, machine learning techniques were integrated to enhance the interpretability and decision support capabilities of the output. According to local climate data and building specifications, annual electricity consumption was simulated, and units were classified into 'low' or 'high' consumption categories using thresholds defined by T & uuml;rkiye's Energy Market Regulatory Authority (EPDK). To improve classification reliability and computational efficiency, a wrapper-based feature selection approach was employed. The Whale Optimization Algorithm (WOA), guided by K-Nearest Neighbors (KNN) fitness evaluation, was used to identify a subset of the most relevant features, and a Support Vector Machine (SVM) was trained on this reduced feature set. The WOA-KNN-SVM model outperformed the baseline SVM classifier across all performance metrics, achieving 98.2 % classification accuracy, with notable improvements in sensitivity, specificity, and Matthews Correlation Coefficient. The results demonstrate that this integrated methodology can effectively support climate-sensitive and energy-efficient design decisions for mass housing in disaster-prone regions. By providing a replicable and scalable decision-support tool aligned with real-world tariff structures, the proposed approach contributes a novel perspective to post-disaster sustainable reconstruction planning.
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    COVID-19 and human development: An approach for classification of HDI with deep CNN
    (Elsevier Sci Ltd, 2023) Kavuran, Gurkan; Gokhan, Seyma; Yeroglu, Celaleddin
    The measures taken during the pandemic have had lasting effects on people's lives and perceptions of the ability of national and multilateral institutions to drive human development. Policies that changed people's behavior were at the heart of containing the spread of the virus. As a result, it has become a systemic human development crisis affecting health, the economy, education, social life, and accumulated gains. This study shows how the relationship of the Human Development Index (HDI), which has combined effects on health, education, and the economy, should be considered in the context of pandemic factors. First, COVID-19 data of the countries received from a public and credible source were extracted and organized into an acceptable structure. Then, we applied statistical feature selection to determine which variables are closely related to HDI and enabled the Deep Con-volutional Neural Network (DCNN) model to give more accurate results. The Continuous Wavelet Transform (CWT) and scalogram methods were used for the time-series data visualization. Three different images of each country are combined into a single image to penetrate each other for ease of processing. These images were made suitable for the input of the ResNet-50 network, which is a pre-trained DCNN model, by going through various preprocessing processes. After the training and validation processes, the feature vectors in the fc1000 layer of the network were drawn and given to the Support Vector Machine Classifier (SVMC) input. We achieved total performance metrics of specificity (88.2%), sensitivity (96.5%), precision (99%), F1 Score (94.9%) and MCC (85.9%).
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    Implementations of TD3 and DDPG Reinforcement Learning Techniques for Tuning PID Controller of TRMS System
    (Springer Heidelberg, 2025) Tufenkci, Sevilay; Alagoz, Baris Baykant; Kavuran, Gurkan; Yeroglu, Celaleddin; Herencsar, Norbert; Mahata, Shibendu
    Reinforcement Learning (RL) is a learning method that utilizes interactions between agents and their environments, providing a valuable tool for controller design through simulations. However, traditional industrial systems such as PID control loops have yet to fully embrace the advantages of RL algorithms for effectively tuning controllers. This study presents an experimental initiative demonstrating the implementation of an RL-driven method for optimal PID controller tuning to address challenges in rotor control, explicitly focusing on the Twin-Rotor Multi-Input Multi-Output System (TRMS). Rotor control presents a complex challenge involving aerodynamics and external disturbances. The research implements two RL algorithms, namely the Deep Deterministic Policy Gradient (DDPG) and the Twin Delay Deep Deterministic Policy Gradient (TD3), in a tailored simulation environment to train RL agents to achieve optimal PID control dynamics. Results of simulation and experimental studies indicate that RL algorithms can be implemented for PID controller tuning when the simulation environment for training the RL algorithms well-represent the dominating dynamics and control complications of real-world systems. In this case, both the simulation and experimental results are in good-agreement.
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    NFSDense201: microstructure image classification based on non-fixed size patch division with pre-trained DenseNet201 layers
    (Springer London Ltd, 2023) Barua, Prabal Datta; Dogan, Sengul; Kavuran, Gurkan; Tuncer, Turker; Tan, Ru-San; Acharya, U. Rajendra
    In the field of nanoscience, the scanning electron microscope (SEM) is widely employed to visualize the surface topography and composition of materials. In this study, we present a novel SEM image classification model called NFSDense201, which incorporates several key components. Firstly, we propose a unique nested patch division approach that divides each input image into four patches of varying dimensions. Secondly, we utilize DenseNet201, a deep neural network pretrained on ImageNet1k, to extract 2920 deep features from the last fully connected and global average pooling layers. Thirdly, we introduce an iterative neighborhood component analysis function to select the most discriminative features from the merged feature vector, which is formed by concatenating the four feature vectors extracted per input image. This process results in a final feature vector of optimal length 698. Lastly, we employ a standard shallow support vector machine classifier to perform the actual classification. To evaluate the performance of NFSDense201, we conducted experiments using a large public SEM image dataset. The dataset consists of 972, 162, 326, 4590, 3820, 3925, 4755, 181, 917, and 1624.jpeg images belonging to the following microstructural categories: biological, fibers, film-coated surfaces, MEMS devices and electrodes, nanowires, particles, pattern surfaces, porous sponge, powder, and tips, respectively. For both four-class and ten-class classification tasks, we evaluated NFSDense201 using subsets of the dataset containing 5080 and 21,272 images, respectively. The results demonstrate the superior performance of NFSDense201, achieving a four-class classification accuracy rate of 99.53% and a ten-class classification accuracy rate of 97.09%. These accuracy rates compare favorably against previously published SEM image classification models. Additionally, we report the performance of NFSDense201 for each class in the dataset.
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    Using artificial intelligence to improve the diagnostic efficiency of pulmonologists in differentiating COVID-19 pneumonia from community-acquired pneumonia
    (Wiley, 2022) In, Erdal; Geckil, Aysegul A.; Kavuran, Gurkan; Sahin, Mahmut; Berber, Nurcan K.; Kuluozturk, Mutlu
    Coronavirus disease 2019 (COVID-19) has quickly turned into a global health problem. Computed tomography (CT) findings of COVID-19 pneumonia and community-acquired pneumonia (CAP) may be similar. Artificial intelligence (AI) is a popular topic among medical imaging techniques and has caused significant developments in diagnostic techniques. This retrospective study aims to analyze the contribution of AI to the diagnostic performance of pulmonologists in distinguishing COVID-19 pneumonia from CAP using CT scans. A deep learning-based AI model was created to be utilized in the detection of COVID-19, which extracted visual data from volumetric CT scans. The final data set covered a total of 2496 scans (887 patients), which included 1428 (57.2%) from the COVID-19 group and 1068 (42.8%) from the CAP group. CT slices were classified into training, validation, and test datasets in an 8:1:1. The independent test data set was analyzed by comparing the performance of four pulmonologists in differentiating COVID-19 pneumonia both with and without the help of the AI. The accuracy, sensitivity, and specificity values of the proposed AI model for determining COVID-19 in the independent test data set were 93.2%, 85.8%, and 99.3%, respectively, with the area under the receiver operating characteristic curve of 0.984. With the assistance of the AI, the pulmonologists accomplished a higher mean accuracy (88.9% vs. 79.9%, p < 0.001), sensitivity (79.1% vs. 70%, p < 0.001), and specificity (96.5% vs. 87.5%, p < 0.001). AI support significantly increases the diagnostic efficiency of pulmonologists in the diagnosis of COVID-19 via CT. Studies in the future should focus on real-time applications of AI to fight the COVID-19 infection.