Yasemin Ayaz Atalan

Dr. Yasemin Ayaz Atalan

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Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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30 September 2022 in Healthcare
Verified
Journal Article
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Abdulkadir AtalanAbdulkadir Atalan
Abdulkadir Atalan
HSHasan Sahin
Hasan Sahin
YAYasemin Ayaz Atalan
Yasemin Ayaz Atalan
A healthcare resource allocation generally plays a vital role in the number of patients treated (pnt) and the patient waiting time (wt) in healthcare institutions. This study aimed to estimate pnt and wt as output variables by considering the number of healthcare resources employed and analyze the cost of health resources to the hospital depending on the cost coefficient (δi) in an emergency department (ED). The integration of the discrete-event simulation (DES) model and machine learning (ML) algorithms, namely random forest (RF), gradient boosting (GB), and AdaBoost (AB), was used to calculate the estimation of the output variables depending on the δi of resources cost. The AB algorithm performed best in almost all scenarios based on the results of the analysis. According to the AB algorithm based on the δ0.0, δ0.1, δ0.2, and δ0.3, the accuracy data were calculated as 0.9838, 0.9843, 0.9838, and 0.9846 for pnt; 0.9514, 0.9517, 0.9514, and 0.9514 for wt, respectively in the training stage. The GB algorithm had the best performance value, except for the results of the δ0.2 (AB had a better accuracy at 0.8709 based on the value of δ0.2 for pnt) in the test stage. According to the AB algorithm based on the δ0.0, δ0.1, δ0.2, and δ0.3, the accuracy data were calculated as 0.7956, 0.9298, 0.8288, and 0.7394 for pnt; 0.8820, 0.8821, 0.8819, and 0.8818 for wt in the training phase, respectively. All scenarios created by the δi coefficient should be preferred for ED since the income provided by the pnt value to the hospital was more than the cost of healthcare resources. On the contrary, the wt estimation results of ML algorithms based on the δi coefficient differed. Although wt values in all ML algorithms with δ0.0 and δ0.1 coefficients reduced the cost of the hospital, wt values based on δ0.2 and δ0.3 increased the cost of the hospital.

27 July 2020 in Sustainability
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Journal Article
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YAYasemin Ayaz Atalan
Yasemin Ayaz Atalan
MTMete Tayanç
Mete Tayanç
KEKamil Erkan
Kamil Erkan
Abdulkadir AtalanAbdulkadir Atalan
Abdulkadir Atalan
This study aims to develop an optimization model for obtaining the maximum benefit from wind power plants (WPPs) to help with reducing external dependence in terms of energy. In this sense, design of experiment and optimization methods are comprehensively combined in the wind energy field for the first time. Existing data from installed WPPs operating in Turkey for the years of 2017 and 2018 are analyzed. Both the individual and interactive effects of controllable factors, namely turbine power (MW), hub height (m) and rotor diameter (m), and uncontrollable factor as wind speed (m/s) on WPPs are investigated with the help of Box-Behnken design. Nonlinear optimization models are utilized to estimate optimum values for each decision variable in order to maximize the amount of energy to be produced for the future. Based on the developed nonlinear optimization models, the optimum results with high desirability value (0.9587) for the inputs of turbine power, hub height, rotor diameter and wind speed are calculated as 3.0670 MW, 108.8424 m, 106.7597 m, and 6.1684 m/s, respectively. The maximum energy output with these input values is computed as 9.952 million kWh per unit turbine, annually. The results of this study can be used as a guideline in the design of new WPPs to produce the maximum amount of energy contributing to supply escalating energy needs by more sustainable and clean ways for the future.
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15 September 2023 in Sustainability
Verified
Journal Article
Open access
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YAYasemin Ayaz Atalan
Yasemin Ayaz Atalan
Abdulkadir AtalanAbdulkadir Atalan
Abdulkadir Atalan
The importance of solar power generation facilities, as one of the renewable energy types, is increasing daily. This study proposes a two-way validation approach to verify the validity of the forecast data by integrating solar energy production quantity with machine learning (ML) and I-MR statistical process control (SPC) charts. The estimation data for the amount of solar energy production were obtained by using random forest (RF), linear regression (LR), gradient boosting (GB), and adaptive boost or AdaBoost (AB) algorithms from ML models. Data belonging to eight independent variables consisting of environmental and geographical factors were used. This study consists of approximately two years of data on the amount of solar energy production for 636 days. The study consisted of three stages: First, descriptive statistics and analysis of variance tests of the dependent and independent variables were performed. In the second stage of the method, estimation data for the amount of solar energy production, representing the dependent variable, were obtained from AB, RF, GB, and LR algorithms and ML models. The AB algorithm performed best among the ML models, with the lowest RMSE, MSE, and MAE values and the highest R2 value for the forecast data. For the estimation phase of the AB algorithm, the RMSE, MSE, MAE, and R2 values were calculated as 0.328, 0.107, 0.134, and 0.909, respectively. The RF algorithm performed worst with performance scores for the prediction data. The RMSE, MSE, MAE, and R2 values of the RF algorithm were calculated as 0.685, 0.469, 0.503, and 0.623, respectively. In the last stage, the estimation data were tested with I-MR control charts, one of the statistical control tools. At the end of all phases, this study aimed to validate the results obtained by integrating the two techniques. Therefore, this study offers a critical perspective to demonstrate a two-way verification approach to whether a system’s forecast data are under control for the future.

30 December 2024 in Applied Sciences
Verified
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YAYasemin Ayaz Atalan
Yasemin Ayaz Atalan
Abdulkadir AtalanAbdulkadir Atalan
Abdulkadir Atalan
This study proposes a two-stage methodology for predicting wind energy production using time, environmental, technical, and locational variables. In the first stage, machine learning algorithms, including random forest (RF), gradient boosting (GB), k-nearest neighbors (kNNs), linear regression (LR), and decision trees (Tree), were employed to estimate energy output. Among these, RF exhibited the best performance with the lowest error metrics (MSE: 0.003, RMSE: 0.053) and the highest R2 value (0.988). In the second stage, analysis of variance (ANOVA) was conducted to evaluate the statistical relationships between independent variables and the predicted dependent variable, identifying wind speed (p < 0.001) and rotor speed (p < 0.001) as the most influential factors. Furthermore, RF and GB models produced predictions most closely aligned with actual data, achieving R2 values of 88.83% and 89.30% in the ANOVA validation phase. Integrating RF and GB models with statistical validation highlighted the robustness of the methodology. These findings demonstrate the robustness of integrating machine learning models with statistical verification methods.

30 June 2021 in İstatistik ve Uygulamalı Bilimler Dergisi
Verified
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YAYasemin Ayaz Atalan
Yasemin Ayaz Atalan
Abdulkadir AtalanAbdulkadir Atalan
Abdulkadir Atalan
This study aimed to use the design of experiment technique to calculate the optimum values of dependent and independent variables considered in the production of quality sugar. This study consists of two stages. Firstly, four different independent variables and one dependent variable data were used for this study. The levels and limits of independent factors were determined as a result of descriptive statistical analysis. They were considered the experiment as a two-level system; a full-factorial design of experiment, including 24 experiments with three replications, was made. Statistical analysis was performed using the data obtained, and it was determined whether the independent variables had an effect on the dependent variable. In the second stage of the study, the optimization model developed in order to obtain optimum results for both dependent and independent variables was run. According to the optimum data obtained in the optimization model, the quality-sugar score was calculated as 13.5821 according to 95% confidence and prediction interval, while the color of sugar was determined to be brown.

30 June 2025 in İstatistik ve Uygulamalı Bilimler Dergisi
Verified
Journal Article
Open access
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Abdulkadir AtalanAbdulkadir Atalan
Abdulkadir Atalan
LGLütfi Alper Gündoğdu
Lütfi Alper Gündoğdu
HKHarun Kahyalık
Harun Kahyalık
YAYasemin Ayaz Atalan
Yasemin Ayaz Atalan
In this study, various machine learning algorithms were evaluated for estimating wind energy production using hourly meteorological data of Yalova province in 2018. The input parameters were input parameters of weather parameters such as temperature, relative humidity, air pressure, wind direction, and wind speed. In the analysis performed on a total of 50530 data points, methods such as Gradient Boosting (GB), Random Forests (RF), k-nearest neighbor (kNN), and Stochastic gradient descent (GBD) were compared. Model performances were evaluated according to Mean Absolute Error (MAE), Mean Square Error (MSE), Root Mean Square Error (RMSE), MAPE, and R2 criteria. According to the results, the best-performing algorithm was RF with an MSE value of 0.039, RMSE value of 0.197, MAE value of 0.081, MAPE value of 0.377, and R² score of 0.961. On the other hand, the SGD model showed the lowest performance with an MSE value of 0.175, RMSE value of 0.418, MAE value of 0.303, MAPE value of 0.581, and R² score of 0.822. These findings show that machine learning models, supported by selecting the correct weather parameters, can provide high accuracy in estimating wind energy production and contribute to energy management policies in this direction.