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Solution‐Based Fabrication of Copper Oxide Thin Film Influence of Transition Metal (Cobalt) Doping on Structural, Morphological, Electrical, and Optical Properties 过渡金属(钴)掺杂对结构、形态、电学和光学性能的影响
Pub Date : 2023-06-06 DOI: 10.31127/tuje.1290655
Samed ÇETİNKAYA
In this study, Cobalt (Co) doped Copper Oxide (CuO) films at different concentrations were deposited on glass substrates, using the Chemical Bath Deposition method. The films were characterized by Field Emission Scanning Electron Microscopy (FESEM), X-Ray Diffraction XRD), Ultra Violet-Visible Spectroscopy (UV-Vis.) and two-point contact method. The SEM showed that nanoplates formed increased in size and voids on the films surface decreased with increasing Co concentration. The XRD patterns revealed an increase in crystallite size with increasing (from 14.40 to 18.60 nm) Co concentration and no secondary phase was formed. The EDS spectra showed the presence of Co in the film composition with increasing concentration. The results of UV-Vis. spectroscopy showed that transmittance and band gap values could be changed with Co doping and thus the CuO band gap could be adjusted with the Co doping. The temperature-dependent current-voltage measurement results obtained with the two-point contact method showed that activation energy levels increased (from 0.134 to 0.232 eV) with increasing Co concentration. It was also observed that the conductivity increased with increasing temperature.
在本研究中,采用化学浴沉积法在玻璃衬底上沉积了不同浓度的钴(Co)掺杂氧化铜(CuO)薄膜。采用场发射扫描电镜(FESEM)、x射线衍射(XRD)、紫外可见光谱(UV-Vis)和两点接触法对薄膜进行了表征。SEM结果表明,随着Co浓度的增加,形成的纳米片尺寸增大,膜表面空隙减小。XRD谱图显示,随着Co浓度的增加(从14.40 nm增加到18.60 nm),晶粒尺寸逐渐增大,未形成二次相。能谱分析表明,随着浓度的增加,薄膜成分中存在Co。紫外-可见的结果。光谱分析结果表明,Co掺杂可以改变CuO的透射率和带隙值,从而可以调节CuO的带隙。用两点接触法测得的温度相关的电流电压结果表明,随着Co浓度的增加,活化能从0.134 eV增加到0.232 eV。电导率随温度的升高而升高。
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引用次数: 0
Optimal Power Flow Analysis with Circulatory System-Based Optimization Algorithm 基于循环系统优化算法的最优潮流分析
Pub Date : 2023-05-29 DOI: 10.31127/tuje.1282429
Hüseyin BAKIR
Optimal power flow (OPF) is one of the most challenging optimization problems of power engineering. Owing to the high computational complexity of the OPF problem, a powerful and robust optimization algorithm is required to solve it. This paper has been centered on the optimization of OPF problem using circulatory system-based optimization (CSBO) algorithm. The solution quality of CSBO is compared with the recently introduced state-of-the-art metaheuristic algorithms i.e., artificial rabbits optimization (ARO), african vultures optimization algorithm (AVOA), and chaos game optimization (CGO). The practicability of the algorithms was evaluated on the IEEE-57 and 118-bus power networks for the optimization of various objectives, i.e., fuel cost, power loss, voltage deviation, and enhancement of voltage stability. Based on OPF results of the IEEE 57-bus power system, it is seen that the best fuel cost and voltage deviation results are calculated to be 41666.2344 $/h and 0.5871 p.u with the CSBO method. Given the OPF results of the IEEE 118-bus power network, it is observed that the CSBO algorithm presented the best fuel cost and active power loss values of 134934.3140 $/h, and 16.4688 MW. Moreover, OPF solutions obtained from 30 algorithm runs were analyzed using the Wilcoxon statistical test method. Consequently, the present paper reports that the CSBO algorithm produces better-quality OPF solutions compared to its competitors and other literature studies.
最优潮流是电力工程中最具挑战性的优化问题之一。由于OPF问题的计算复杂度很高,需要一种强大的鲁棒优化算法来求解。本文主要研究了基于循环系统优化(CSBO)算法的OPF优化问题。将CSBO的解质量与最近引入的最先进的元启发式算法,即人造兔子优化算法(ARO)、非洲秃鹫优化算法(AVOA)和混沌博弈优化算法(CGO)进行了比较。在IEEE-57和118母线电网上对算法的实用性进行了评估,以优化燃料成本、功率损耗、电压偏差和增强电压稳定性等多个目标。基于IEEE 57总线电力系统的OPF结果可以看出,采用CSBO方法计算得到的最佳燃料成本和电压偏差分别为41666.2344美元/h和0.5871 p.u。结合IEEE 118总线电网的OPF结果可知,CSBO算法的燃油成本和有功损耗分别为134934.3140 $/h和16.4688 MW,最优。利用Wilcoxon统计检验方法对30次算法运行得到的OPF解进行分析。因此,本文报告了CSBO算法比其竞争对手和其他文献研究产生更好质量的OPF解。
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引用次数: 0
Counterface Soil Type and Loading Condition Effects on Granular/Cohesive Soil – Geofoam Interface Shear Behavior 面土类型和荷载条件对颗粒/粘性土-土工泡沫塑料界面剪切性能的影响
Pub Date : 2023-05-15 DOI: 10.31127/tuje.1279304
Tanay KARADEMİR
The primary function of the geofoams consists of providing; i) lightweight fill for construction on soft ground (i.e. embankment), ii) relatively stiff base for subgrade installation below a highway (i.e. roadway, runway foundation), bridge approach (i.e. abutment backfill), and iii) slope stabilization for retaining structures. In those applications, the geofoams are in direct contact with soils and this interaction results in development of an interface where likelihood of a failure to initiate is higher. For this reason, the frictional resistance and the type of shear response mobilizing at these soil – geofoam interfaces control the stability of composite system, and hence, govern the integrity of the infrastructure. Soil – geofoam interfaces have been studied through an extensive experimental program by performing multiple series of interface shear tests using two different granular soils (i.e. beach sand and construction material sand) and one cohesive soil (i.e. bentonite clay) as well as a soil mixture containing 75% sand and 25% clay by dry weight at distinct loading conditions (i.e. normal stresses: 25, 100, 250; low, moderate, high loading conditions, respectively). Using the shear stress versus horizontal displacement curves obtained, some important engineering design parameters including peak shear stress, residual shear stress, interface sensitivity (i.e. peak/residual ratio) and displacement required to reach peak stress have been determined and the variations in those interface mechanical properties as a function of loading condition and counterface soil type have been investigated. It was seen that the peak as well as residual shear stresses increased with an increase in normal stress. Further, granular soil (sand) interfaces demonstrated relatively larger frictional strengths (both peak and residual) as compared to that of not only cohesive soil (clay) interface but also soil mixture (sand and clay) interface. Additionally, the higher the angularity of granular soil particles became, the larger the interface shear strengths (peak and residual), when sheared against geofoams, developed in light of experimental results attained as a result of interface shear tests on different material combinations.
土工泡沫的主要功能包括提供;I)在软土地(即路堤)上进行施工的轻质填充物,ii)在高速公路(即道路、跑道基础)、桥梁引道(即桥台回填)下面安装路基的相对坚硬的基础,以及iii)用于挡土结构的边坡稳定。在这些应用中,土工泡沫与土壤直接接触,这种相互作用导致界面的发展,在这种界面中,启动失败的可能性更高。因此,摩擦阻力和在这些土工泡沫界面调动的剪切响应类型控制着复合体系的稳定性,从而控制着基础设施的完整性。通过广泛的实验程序,通过使用两种不同的颗粒土(即沙滩砂和建筑材料砂)和一种粘性土(即膨润土粘土)以及含有75%沙子和25%粘土的土壤混合物在不同的加载条件下(即正常应力:25,100,250;分别为低、中、高负荷工况)。利用得到的剪应力与水平位移曲线,确定了一些重要的工程设计参数,包括峰值剪应力、残余剪应力、界面灵敏度(即峰值/残余比)和达到峰值应力所需的位移,并研究了这些界面力学特性随加载条件和界面土类型的变化规律。随着法向应力的增大,峰值剪应力和残余剪应力均增大。此外,颗粒土(砂)界面的摩擦强度(峰值和残余)不仅比粘性土(粘土)界面大,而且比混合土(砂和粘土)界面大。此外,根据不同材料组合的界面剪切试验结果,颗粒土颗粒角度越高,与土工泡沫塑料剪切时的界面剪切强度(峰值和残余)越大。
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引用次数: 0
Comparison of CNN-Based Methods for Yoga Pose Classification 基于cnn的瑜伽姿势分类方法比较
Pub Date : 2023-05-11 DOI: 10.31127/tuje.1275826
Vildan ATALAY AYDIN
Yoga is an exercise developed in ancient India. People perform yoga in order to have mental, physical, and spiritual benefits. While yoga helps build strength in the mind and body, incorrect postures might result in serious injuries. Therefore, yoga exercisers need either an expert or a platform to receive feedback on their performance. Since access to experts is not an option for everyone, a system to provide feedback on the yoga poses is required. To this end, commercial products such as smart yoga mats and smart pants are produced; Kinect cameras, sensors, and wearable devices are used. However, these solutions are either uncomfortable to wear or not affordable for everyone. Nonetheless, a system that employs computer vision techniques is a requirement. In this paper, we propose a deep-learning model for yoga pose classification, which is the first step of a quality assessment system. We introduce a wavelet-based model that first takes wavelet transform of input images. The acquired subbands, i.e., approximation, horizontal, vertical, and diagonal coefficients of the wavelet transform are then fed into separate convolutional neural networks (CNN). The obtained probability results for each group are fused in order to have the final yoga class prediction. A publicly available dataset with 5 yoga poses is used. Since the number of images in the dataset is not enough for a deep learning model, we also perform data augmentation to increase the number of images. We compare our results to a CNN model and the three models that employ the subbands separately. Results obtained using the proposed model outperforms the accuracy output achieved with the compared models.
瑜伽是古印度发展起来的一种运动。人们练习瑜伽是为了获得心理、身体和精神上的好处。虽然瑜伽有助于增强身心的力量,但不正确的姿势可能会导致严重的伤害。因此,瑜伽练习者需要一个专家或一个平台来接收他们的表现反馈。因为并不是每个人都能获得专家的帮助,所以需要一个系统来提供关于瑜伽姿势的反馈。为此,生产出智能瑜伽垫、智能裤子等商业产品;使用Kinect摄像头、传感器和可穿戴设备。然而,这些解决方案要么穿着不舒服,要么不是每个人都负担得起。尽管如此,一个采用计算机视觉技术的系统是必需的。在本文中,我们提出了一个瑜伽姿势分类的深度学习模型,这是质量评估系统的第一步。我们引入了一种基于小波的模型,该模型首先对输入图像进行小波变换。获得的子带,即小波变换的近似、水平、垂直和对角系数,然后被馈送到单独的卷积神经网络(CNN)中。将得到的每组概率结果进行融合,从而得到最终的瑜伽课预测。使用了一个公开的数据集,其中包含5个瑜伽姿势。由于数据集中的图像数量不足以用于深度学习模型,我们还执行数据增强以增加图像数量。我们将我们的结果与CNN模型和分别使用子带的三种模型进行比较。使用该模型获得的结果优于使用比较模型获得的精度输出。
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引用次数: 0
Prediction of elevation points using three different heuristic regression techniques 使用三种不同的启发式回归技术预测高程点
Pub Date : 2023-04-17 DOI: 10.31127/tuje.1257847
Vahdettin Demir, Ramazan Doğu
The aim of this study is to estimate the elevation points used in the creation of the digital elevation model, which is the most important data of the projects and required in the engineering project, using horizontal and vertical location informations and three different heuristic regression techniques. As the study area, an area with mid-level elevations, located in the Marmara region, and covering a part of the intersection of Edirne, Kırklareli and Tekirdağ provinces was chosen. In the study, the estimations were investigated for three different sized areas, and these areas are square areas with the dimensions of 1x1 km, 10x10 km and 100x100 km, respectively. A total of 3500 elevation points were used in the study, and this number is constant in all areas, and 60% of these points were used in the testing phase and 40% in the training phase. The models used in the study are M5 model tree (M5-tree), multivariate adaptive regression curves (MARS) and Least Square Support Vector Regression (LSSVR). The results of the models were evaluated according to three different comparison criteria. These, coefficient of determination (R2), Mean Absolute Error (MAE) and Root Mean Square Error (RMSE) were used. When the modeling results are examined; M5-Tree regression method gave the best results (1), LSSVR method was better than MARS methods (2), The most successful input data was found in datasets using X and Y coordinates information, and the worst results were found in datasets using X coordinates (3). As the study area increased, the model performance did not improve (4). The least error was obtained in the modeling of 1x1 km area, and the highest R² was obtained from the modeling of 10x10 km area (5). It was concluded that the M5-tree method is a very successful method in height modeling.
本研究的目的是利用水平和垂直位置信息以及三种不同的启发式回归技术,估计用于创建数字高程模型的高程点,这是项目中最重要的数据,也是工程项目所需的数据。作为研究区域,选择了位于马尔马拉地区的一个中等海拔区域,覆盖了Edirne, Kırklareli和tekirdalu省交界处的一部分。在研究中,研究了三个不同大小的区域,这些区域分别为1x1 km, 10x10 km和100x100 km的方形区域。研究中总共使用了3500个高程点,这个数字在所有区域都是恒定的,其中60%的高程点用于测试阶段,40%用于训练阶段。研究中使用的模型有M5模型树(M5-tree)、多变量自适应回归曲线(MARS)和最小二乘支持向量回归(LSSVR)。根据三种不同的比较标准对模型的结果进行评价。这些,决定系数(R2),平均绝对误差(MAE)和均方根误差(RMSE)。当对建模结果进行检验时;M5-Tree回归方法的结果最好(1),LSSVR方法优于MARS方法(2),X和Y坐标信息的数据集输入数据最成功,X坐标信息的数据集结果最差(3)。随着研究面积的增加,模型性能没有提高(4)。在1x1 km区域建模时误差最小。在10x10 km区域的模拟中,R²最高(5)。结果表明,M5-tree方法是一种非常成功的高度模拟方法。
{"title":"Prediction of elevation points using three different heuristic regression techniques","authors":"Vahdettin Demir, Ramazan Doğu","doi":"10.31127/tuje.1257847","DOIUrl":"https://doi.org/10.31127/tuje.1257847","url":null,"abstract":"The aim of this study is to estimate the elevation points used in the creation of the digital elevation model, which is the most important data of the projects and required in the engineering project, using horizontal and vertical location informations and three different heuristic regression techniques. As the study area, an area with mid-level elevations, located in the Marmara region, and covering a part of the intersection of Edirne, Kırklareli and Tekirdağ provinces was chosen. In the study, the estimations were investigated for three different sized areas, and these areas are square areas with the dimensions of 1x1 km, 10x10 km and 100x100 km, respectively. A total of 3500 elevation points were used in the study, and this number is constant in all areas, and 60% of these points were used in the testing phase and 40% in the training phase. The models used in the study are M5 model tree (M5-tree), multivariate adaptive regression curves (MARS) and Least Square Support Vector Regression (LSSVR). The results of the models were evaluated according to three different comparison criteria. These, coefficient of determination (R2), Mean Absolute Error (MAE) and Root Mean Square Error (RMSE) were used. When the modeling results are examined; M5-Tree regression method gave the best results (1), LSSVR method was better than MARS methods (2), The most successful input data was found in datasets using X and Y coordinates information, and the worst results were found in datasets using X coordinates (3). As the study area increased, the model performance did not improve (4). The least error was obtained in the modeling of 1x1 km area, and the highest R² was obtained from the modeling of 10x10 km area (5). It was concluded that the M5-tree method is a very successful method in height modeling.","PeriodicalId":23377,"journal":{"name":"Turkish Journal of Engineering and Environmental Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80426107","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Determination of optimum design parameters of glow plug and experimental verification 辉光塞最佳设计参数的确定及实验验证
Pub Date : 2023-04-15 DOI: 10.31127/tuje.1062681
Muciz Özcan, M. F. Ünlerşen, M. Şen
In Diesel Engines, the heat energy obtained from the glow plug increases the engine's ability to start up in cold climatic conditions and significantly reduces emissions of harmful gases leaving the exhaust. In cold climatic conditions, before the start off of diesel vehicles it is necessary to wait for about 10 s the cylinder block heating. This period negatively affects driving comfort. In this study, the mathematical results of the processes to optimize the time required for the glow plug to reach the required temperature have been experimentally proven. A test apparatus was developed to confirm experimentally the theoretical results. Thanks to these improvements concerning the manufacture of the glow plug, the time period to reach 850 ° C has been reduced by approximately 5 s. The proposed design is in accordance with the glow plug present in the market. Currently the whole glow plug must be changed at the end of lifetime, with our improvement only the inner tube resistance can be easily changed involving a cost reduction by about 60%.
在柴油发动机中,从发光塞获得的热能增加了发动机在寒冷气候条件下启动的能力,并大大减少了废气中有害气体的排放。在寒冷的气候条件下,柴油车在启动前有必要等待10 s左右的缸体加热。这段时间会对驾驶舒适性产生负面影响。在本研究中,优化辉光塞达到所需温度所需时间的过程的数学结果已得到实验证明。研制了实验装置,对理论结果进行了实验验证。由于这些关于发光塞制造的改进,达到850°C的时间缩短了大约5秒。建议的设计与目前市场上的发光插头一致。目前,整个辉光插头必须在使用寿命结束时更换,通过我们的改进,只有内管电阻可以很容易地改变,成本降低了约60%。
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引用次数: 0
Collapse capacity assessment of non-ductile open ground story reinforced concrete frame 非延性开阔地面层钢筋混凝土框架倒塌能力评价
Pub Date : 2023-04-15 DOI: 10.31127/tuje.1071965
Emre AKIN, Emad KANAS
It is a well-known fact that the absence of infill walls at the ground story, which is termed as “open ground story” may lead to a soft-story deficiency, especially in the case of non-ductile buildings. The previous severe earthquakes have shown that catastrophic destruction may occur in such a condition. Therefore, the seismic assessment of open ground story reinforced frames, where the effects of infill walls are incorporated, is of vital importance. However, the effects of infill walls are generally disregarded or considered indirectly in the seismic assessment procedures of the codes. This may mislead the actual condition of the open ground story buildings at different performance levels. This study aims to assess a non-ductile reinforced concrete frame with an open ground story regarding the collapse prevention performance level. The pushover and incremental dynamic analyses results are evaluated following the code limitations for collapse prevention. The results demonstrate the measure of misleading caused by the ignorance of infills at the upper stories while applying these code limitations.
众所周知的事实是,在地面层(被称为“开放地面层”)缺乏填充墙可能导致软层不足,特别是在非延性建筑的情况下。以前的大地震表明,在这种情况下可能会发生灾难性的破坏。因此,考虑填充墙影响的露天层加筋框架的抗震评估是至关重要的。然而,在规范的地震评估过程中,填充墙的影响通常被忽略或间接考虑。这可能会误导不同性能水平的开放地面层建筑的实际情况。本研究旨在评估具有开放地面层的非延性钢筋混凝土框架的抗倒塌性能水平。根据防止倒塌的规范限制,对推覆和增量动态分析结果进行了评估。结果表明,在应用这些代码限制时,由于忽略上层的填充而造成的误导的度量。
{"title":"Collapse capacity assessment of non-ductile open ground story reinforced concrete frame","authors":"Emre AKIN, Emad KANAS","doi":"10.31127/tuje.1071965","DOIUrl":"https://doi.org/10.31127/tuje.1071965","url":null,"abstract":"It is a well-known fact that the absence of infill walls at the ground story, which is termed as “open ground story” may lead to a soft-story deficiency, especially in the case of non-ductile buildings. The previous severe earthquakes have shown that catastrophic destruction may occur in such a condition. Therefore, the seismic assessment of open ground story reinforced frames, where the effects of infill walls are incorporated, is of vital importance. However, the effects of infill walls are generally disregarded or considered indirectly in the seismic assessment procedures of the codes. This may mislead the actual condition of the open ground story buildings at different performance levels. This study aims to assess a non-ductile reinforced concrete frame with an open ground story regarding the collapse prevention performance level. The pushover and incremental dynamic analyses results are evaluated following the code limitations for collapse prevention. The results demonstrate the measure of misleading caused by the ignorance of infills at the upper stories while applying these code limitations.","PeriodicalId":23377,"journal":{"name":"Turkish Journal of Engineering and Environmental Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136340142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Machine learning empowered prediction of geolocation using groundwater quality variables over YSR district of India 机器学习增强了利用印度YSR地区地下水质量变量预测地理位置的能力
Pub Date : 2023-04-12 DOI: 10.31127/tuje.1223779
Jagadish Kumar MOGARAJU
Machine Learning (ML) has been used in the prediction of geolocation with improved accuracies in this work. The pre-processed data was subjected to prediction analytics using 22 machine learning algorithms over regression mode. It was observed that Extra Trees Regressor performed well with better accuracies in predicting latitude, longitude, and Haversine distance, respectively. Regression models like CatBoost, Extreme Gradient boosting, Light Gradient boosting machine, and Gradient boosting regressor were also tested. The R2 values were computed for each case, and we obtained 0.96 (Longitude), 0.98 (Latitude), and 0.96 (Haversine), respectively. The evaluation of models was done using metrics like MAE, MASE, RMSE, R2, RMSLE, and MAPE and R2 is considered most important than others. The effect of data point was calculated using Cooks’ distance, and the variable fluoride has a significant impact on the prediction accuracy of Longitude followed by RSC, Cl, SO4, SAR, NO3, NA, Ca, EC and pH variables. In the prediction of latitude, the SAR variable played a significant role, followed by Na and TH. According to the t-SNE manifold, three longitude values were quite different from the others. This work is supported by some of the manifests like Cooks’ distance outlier detection, feature importance plot, t-SNE manifold, prediction error plot, residuals plot, RFECV plot, and validation curve. This work is done to report that the challenge of predicting both latitude and longitude on a common ground is solved partially, if not completely, and machine learning tools can be used for this purpose. Haversine distance can be obtained from latitude and longitude and can be used in the prediction of geolocation.
在这项工作中,机器学习(ML)已被用于预测地理位置,并提高了准确性。预处理后的数据在回归模式上使用22种机器学习算法进行预测分析。观察到Extra Trees Regressor分别在预测纬度、经度和哈弗辛距离方面表现良好,精度较高。对CatBoost、Extreme Gradient boosting、Light Gradient boosting machine、Gradient boosting regressor等回归模型进行了测试。计算每个病例的R2值,我们分别得到0.96(经度)、0.98(纬度)和0.96(哈弗辛)。模型的评估使用指标如MAE、MASE、RMSE、R2、RMSLE和MAPE,其中R2被认为是最重要的。利用库氏距离计算数据点的影响,氟变量对经度的预测精度影响显著,其次是RSC、Cl、SO4、SAR、NO3、NA、Ca、EC和pH变量。在纬度预测中,SAR变量的作用最显著,其次是Na和TH。根据t-SNE流形,三个经度值与其他经度值相差很大。本文的工作得到了库克斯距离异常点检测、特征重要性图、t-SNE流形、预测误差图、残差图、RFECV图和验证曲线等表的支持。这项工作的完成是为了报告在一个共同的基础上预测纬度和经度的挑战是部分解决的,如果不是完全解决的话,机器学习工具可以用于此目的。哈弗斯距离可由经纬度得到,可用于地理位置的预测。
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引用次数: 0
Comparison of commodity prices by using machine learning models in the COVID-19 era 基于机器学习模型的新冠肺炎时代商品价格比较
Pub Date : 2023-03-24 DOI: 10.31127/tuje.1196296
Sena Alparslan, T. Uçar
Commodity products such as gold, silver, and metal have been seen as safe havens in past economic crises. This situation increases the interest in commodity products. Due to the COVID-19 pandemic, quarantine decisions and precautions have caused an economic slowdown in stock markets and consumer activities. This inactivity in the economy has led to the COVID-19 recession that started in February 2020. Because of the increase in the number of COVID-19 cases, the difficulty of physical buying-selling transactions has shown that commodity products can be a safe investment tool. Based on the fact that machine learning approaches gained importance in commodity price prediction, the main goal of this study is to understand whether machine learning methods are meaningful for commodity price prediction even in extraordinary situations. To measure commodities’ price volatility, a data set obtained from Borsa İstanbul is separated into pre-COVID-19 and COVID-19 periods. Daily prices for gold and silver commodities, from July 2018, which is before the ongoing COVID-19 recession, to October 2021 are used. The performances of the machine learning models were compared with MAE, MAPE, and RMSE metrics.
在过去的经济危机中,黄金、白银和金属等大宗商品一直被视为避风港。这种情况增加了对商品的兴趣。由于COVID-19大流行,隔离决定和预防措施导致股市和消费者活动的经济放缓。这种经济停滞导致了2020年2月开始的新冠肺炎经济衰退。由于新冠肺炎病例数量的增加,实物买卖交易的困难表明,大宗商品产品可以成为一种安全的投资工具。基于机器学习方法在商品价格预测中越来越重要的事实,本研究的主要目标是了解即使在特殊情况下机器学习方法对商品价格预测是否有意义。为了衡量商品的价格波动,从Borsa İstanbul获得的数据集被分为COVID-19前和COVID-19时期。本文使用了2018年7月至2021年10月期间黄金和白银商品的每日价格,2018年7月是在新冠肺炎经济衰退之前。将机器学习模型的性能与MAE、MAPE和RMSE指标进行比较。
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引用次数: 0
Assessment of Engineering Geology and Grouting Applications in Yalnızardıç Dam Site (Antalya, Turkey) Yalnızardıç坝址工程地质及注浆应用评价(土耳其安塔利亚)
Pub Date : 2023-03-16 DOI: 10.31127/tuje.1221774
Ömür ÇİMEN, Halil İbrahim GÜNAYDIN
The Yalnızardıç RCC dam constructed in 2015 is located in the Mediterranean region of Turkey, and it is intended for electric power production. The dam is approximately 303 m long and 92 m height. In this paper, the geotechnical properties of Yalnızardıç Dam's foundation and the grouting methods used to improve this foundation were examined to determine its performance for grouting. Engineering geological mapping, drilling, laboratory tests, and water pressure tests were undertaken to specify the foundation properties. In a consequence of tests, high-permeable and permeable zones were identified in the dam axis area. Grout curtain, including two rows of grouting holes, were built in the left abutment, thalweg and right abutment in accordance with the Lugeon tests and RQD results. Also, blanket (consolidation) grouts were built all foundation areas. Check boreholes along the foundation were opened after grouting treatment and Lugeon tests were performed. The results from the check boreholes indicated that average Lugeon (LU) values reduced, and the values were within the recommended limit. The process shows considerable accuracy in evaluating grouting efficiency.
2015年建成的Yalnızardıç碾压混凝土大坝位于土耳其地中海地区,用于发电。大坝大约303米长,92米高。本文通过对Yalnızardıç大坝地基的岩土力学特性及加固地基的注浆方法的研究,确定了该坝基的注浆性能。进行了工程地质测绘、钻井、实验室测试和水压测试,以确定基础特性。通过试验,确定了坝体轴线区域的高渗透区和渗透区。根据Lugeon试验和RQD结果,在左桥台、桥身和右桥台设置灌浆帷幕,包括两排灌浆孔。此外,在所有基础区域都进行了地毯式(固结)灌浆。灌浆处理后沿基础开检孔,进行吕根试验。检查井的结果表明,平均吕氏值(LU)降低,且在推荐范围内。该方法在评价注浆效率方面具有较高的准确性。
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引用次数: 0
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Turkish Journal of Engineering and Environmental Sciences
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