Sürdürülebilir Kalkınma Amaçları
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- MakaleYalnız künye2024Comparison of histogram-curve fitting-based and global threshold methods for cloud detection
Günen, M. Akif
The goal of this research is fit the best curve to the image histogram using polynomial (i.e., linear, quadratic, cubic, and quartic), Fourier and Gaussian with two different term numbers, and Bezier functions, and then compare their performance with nine automatic state-of-the-art thresholding methods: Shanbhag, Triangle, Huang, Intermode, IsoData, Li's, Maximum entropy, Moment, and Otsu. The visible bands of the Landsat-9, Landsat-8, and Sentinel 2 satellite images are averaged to create an index map, which was used to perform the cloud detection. Since many satellites system only has visible bands, the average index map was used. Three different images which include various cloud types were clipped from each satellite imaging. Thresholding methods were evaluated using statistical tools such as structural similarity index measure (SSIM), peak signal-to-noise ratio (PSNR), and universal image quality index (UIQI), accuracy, Cohen's kappa, precision, recall, F-Measure, and G-Mean. The histogram-based approaches that performed the best after Li's method were Bezier (96.71% accuracy and 99.83% SSIM), 2nd Gaussian (97.62% precision), Quartic (80.56% kappa, 16.16% PSNR, 82.45% F-Measure, and 89.52%), and 2nd Fourier (81.08% recall and 89.27% G-Mean), according to the average statistics of all images. Additionally, methods other than Shanbhag yielded favorable results (more than 90% accuracy).
- MakaleYalnız künye2023Local gravity and magnetic anomalies associated with the oil and gas reservoirs in the cretaceous carbonate deposits of Yevlakh-Agjabedi depression, Azerbaijan
Gadirov, Vagif G.; Maden, Nafiz; Gadirov, Kamran V.
Local gravity and magnetic anomalies are employed to identify potential hydrocarbon reservoirs in the Middle Kura Depression (MKD) within the South Caspian basin in Azerbaijan. The MKD basin in Azerbaijan including the Yevlakh-Agjabedi trough covers a large part of the Kura intermountain basin between the Greater and Lesser Caucasus. In the study region, several local gravity and magnetic anomalies are discovered related to oil and gas deposits in the sedimentary depression whose thickness is 12–14 km. Gravity minima and maxima expressed by different wavelength anomalies are indicative of density variations within the basin. Local gravity minima with an intensity of 0.3–0.4 mGal identified in the study areas are related to the oil–gas deposits. While the local positive magnetic anomalies are associated with the volcanic formations, local negative magnetic anomalies appear over the productive parts of the buried structure within the sedimentary complex. Intense local magnetic minima anomalies with an intensity of 20–30 nT are evidence of oil and gas accumulations. The limitations of traditional methods for interpreting gravity and magnetic data to locate oil and gas fields have led to the use of gravity field gradients. This alternative approach has proven advantageous, as it confirms the results of gravity exploration and is useful for directly searching for hydrocarbons.
- MakaleAçık Erişim2023Transfer Learning Approach and Nucleus Segmentation with MedCLNet Colon Cancer Database
Reis, Hatice Catal; Turk, Veysel
Machine learning has been recently used especially in the medical field. In the diagnosis of serious diseases such as cancer, deep learning techniques can be used to reduce the workload of experts and to produce quick solutions. The nuclei found in the histopathology dataset are an essential parameter in disease detection. The nucleus segmentation was performed using the colorectal histology MNIST dataset for nucleus detection in this study. The graph theory, PSO, watershed, and random walker algorithms were used for the segmentation process. In addition, we present the 10-class MedCLNet visual dataset consisting of the NCT-CRC-HE-100 K dataset, LC25000 dataset, and GlaS dataset that can be used in transfer learning studies from deep learning techniques. The study proposes a transfer learning technique using the MedCLNet database. Deep neural networks pre-trained with the proposed transfer learning method were used in the classification with the colorectal histology MNIST dataset in the experimental process. DenseNet201, DenseNet169, InceptionResNetV2, InceptionV3, ResNet152V2, ResNet101V2, and Xception deep learning algorithms were used in transfer learning and the classification studies. The proposed approach was analyzed before and after transfer learning with different methods (DenseNet169 + SVM, DenseNet169 + GRU). In the performance measurement, using the colorectal histology MNIST dataset, 94.29% accuracy was obtained in the DenseNet169 model, which was initiated with random weights in the multi-classification study, and 95.00% accuracy after transfer learning was applied. In comparison with the results obtained from empirical studies, it was demonstrated that the proposed method produced satisfactory outcomes. The application is expected to provide a secondary evaluation for physicians in colon cancer detection and the segmentation. Graphical Abstract: [Figure not available: see fulltext.].
- MakaleYalnız künye2023A Proposed V2V Path Loss Model: Log-Ray
Kuzulugil, Kenan; Tugcu, Zeynep Hasirci; Cavdar, Ismail Hakki
Vehicle-to-vehicle (V2V) communication that has prominent involvement in the design of innovative communication solutions for the intelligent transportation system. Therefore, to develop V2V channel models, the knowledge of the propagation channel on which comprehensive research efforts have been carried is vital. In this study, we focused on the analysis and modeling of path loss characteristics for V2V communications and proposed a log-ray path loss model with the motivation of overcoming remarkable fitting errors between the two-ray model and measured data where the path loss exponent corresponds to different from 2. First, channel measurements were performed at 5.9 GHz with commercially available DSRC OBU devices for five different scenarios in typical highway and suburban environments in Gümüşhane, Turkey. Then, the large-scale characteristics of different propagation scenarios were analyzed and the proposed log-ray model performance was compared with commonly used log-distance and two-ray path loss models qualitatively and quantitatively. On the other hand, analysis of small-scale modeling and shadowing were also conducted for all scenarios and presented in the results. The findings clearly demonstrate that the proposed log-ray path loss model fits the measured data with a smaller RMSE value (2.54 dB) than the results of the log-distance (3.07 dB) and two-ray (3.72 dB) path loss models in the literature. In other words, the proposed model has approximately 17.5% and 32% increase in fitting performance according to the log-distance and the two-ray path loss models, respectively. The study results will be helpful for better performance analysis and system design of V2V communication.
- MakaleYalnız künye2023Geochemical characterization of late Jurassic–early Cretaceous age limestones from Gümüşhane (NE-Türkiye): identification of the source of organic matter and paleo-environment conditions
Eker, Çiğdem Saydam; Arı, Uğur Volkan
Samples from late Jurassic–early Cretaceous age limestones in five different areas in the Gümüşhane region (NE-Türkiye), were studied using TOC/Rock–Eval, and some trace elements analysis, to evaluate their organic material source, type, thermal maturity, and paleo-environment conditions. The studied carbonate rocks are characterized by 90 m thick in the Bağlarbaşı section, 420 m in the Gülaçar, 584 m in the Ünlüpınar, 375 m in the Mescitli, and 272 m in the Yuvacık. The carbonate rocks are generally represented by, from bottom to top, dolomite, oolitic, sparitic, sandy, micritic, clayey, and bituminous limestones. Average total organic carbon (TOC) values are 0.14, 0.16, 0.20, 0.12, and 0.20% in the Bağlarbaşı, Gülaçar, Ünlüpınar, Mescitli, and Yuvacık sections, respectively. Organic material in the limestones consists of Type II-III kerogen, indicating that a mixture of terrigenous higher plants–marine aquatic organisms was the main source. Average Tmax values and Tmax-based vitrinite reflectance values (Ro %) are calculated as 435 and 0.67, 444 and 0.83, 431 and 0.60, 442 and 0.79, and 437 °C and 0.70 in the Bağlarbaşı, Gülaçar, Ünlüpınar, Mescitli, and Yuvacık sections, respectively, indicating that the samples have generally reached thermal maturity. The limestones in the Gülaçar, Mescitli, and Yuvacık areas are probably well-drained rocks that were extracted and originated hydrocarbon efficiently from the limestone fractures. In general, a non-marine–sometimes marine deposition environment for the carbonates is indicated by total sulfur values. V/Ni and Sr/Ba ratios indicate a stratified water column with high–low salinity and anoxic–oxic bottom water circumstances and accordingly a transitional sedimentation environment.
- MakaleYalnız künye2023Investigating the environmental Kuznets curve hypothesis with recovered paper consumption, human development index, urbanization, and forest footprint
Aydin, M.; Koc, P.; Tumay, M.
The aim of this study, which covers the period from 1991 to 2017, is to analyze the relationships between recovered paper consumption, human development index, urbanization rate, and forest footprint in the framework of the Environmental Kuznets Curve (EKC) hypothesis in the 10 countries that consume the most recovered paper. Considering that wood is the raw material of paper, the study investigates whether the increase in the consumption of recovered paper has a positive effect on the forest footprint. Therefore, unlike other studies, the dependent variable of the EKC model is the forest footprint. The study is original in that it is the first to analyze the effects of recovered paper consumption on environmental degradation in the context of the EKC hypothesis. To analyze the relationships between the variables, we use panel cointegration tests based on AMG and CCE estimators, which allow analysis on both a country and group basis. According to the results, the EKC hypothesis is valid only in the Netherlands. While there is a statistically significant and negative relationship between recovered paper consumption and forest footprint in the Netherlands, there is a statistically significant and negative relationship between urbanization and forest footprint in Italy. Economic and ecological benefits and costs must be considered to measure the net benefit of waste management programs. In addition, to analyze how environmental impacts change over time, ecological footprint and gas emissions during waste generation or disposal should be measured similarly to carbon emissions.
- MakaleAçık Erişim2022Radio-elemental microzonation (RELMIC): a case study of Karadeniz Technical University Campus and surroundings (Trabzon, Turkey)
Altundaş, S.; Çınar, H.
In situ radioactivity measurements were performed to describe and map the relationship between the radioactive concentration distribution on the surface and geological formations in the Karadeniz Technical University (KTU) campus and surrounding area located on the shore of the Black Sea in NE Turkey. The concentrations of radio-elements (eU, eTh, and K) and dose rate values were measured using a portable gamma-ray spectrometer with NaI(Tl) crystal at 150 points in the study area with a duration of 5 min for each measurement point. In addition, the geochemical radio-element ratios (eTh/eU, K/eU, and eU/eTh) give information about the origin of the rocks, and radiological hazard parameters for humans and the environment were also calculated. Average values of eU, eTh, and K concentrations, and dose rate, were calculated to be 3.59 ppm, 13.46 ppm, 0.84%, and 65.38 nGy/h, respectively. While the highest concentrations of radio-element and dose rate values were recorded at outcrops of Eocene-Neogene basaltic rocks and red clays, which are the weathering product of the Kabaköy formation, the lower anomaly zones coincide with brown and reddish brown forest and agricultural soils of volcanic origin in the study area. According to the average radio-element ratios, it was concluded that the rocks in the study area do not completely originate from the crust, but formed as a result of the mixture of upper mantle and continental crust. All the calculated hazard parameters seem to be lower than the internationally recommended values, and there is no cancer risk in and around the campus area.
- DergiJournal of Digital Imaging
- DergiInternational Journal of Environmental Science and Technology