Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Book Part Citation - Scopus: 4Application of Fuzzy Logic in Water Resources Engineering(Elsevier, 2022) Tayfur, GökmenThis chapter introduces the fundamentals of fuzzy logic (FL), fuzzy sets, and fuzzy model components such as the fuzzification, the fuzzy rule base, the fuzzy inference engine, and the defuzzification. The processes of the fuzzy model components are presented by working on the examples from the water resources engineering application problems. This chapter also discusses the merits and the shortcomings of the fuzzy modeling. Hydrological processes have inherent source of uncertainty, for which the fuzzy set theory can be an effective solution tool. © 2023 Elsevier Inc. All rights reserved.Book Part Citation - Scopus: 1Developments in Sediment Transport Modeling in Alluvial Channels(Elsevier, 2022) Tayfur, GökmenThis chapter discusses the developments in the mathematical modeling of sediment transport dynamics in alluvial channels. Starting with early experimental and empirical studies, it goes on to treating the processes in 1D, 2D, and 3D uniform sediment transport. Finally, it describes the treatment of the processes in 3D nonuniform sediment transport considering turbulence effects. While introducing the advancements in mathematical modeling of the dynamics, the chapter also discusses the outstanding issues like the treatment of the particle fall velocity, the particle velocity, and sediment transport rate function. © 2023 Elsevier Inc. All rights reserved.Book Part Citation - Scopus: 3Real-Time Flood Hydrograph Predictions Using Rating Curve and Soft Computing Methods (ga, Ann)(Elsevier, 2022) Tayfur, GökmenThis chapter introduces hydraulic and hydrologic flood routing methods in natural channels. It details hydrological flood routing methods of the Rating Curve and Muskingum. Based on the rating curve method (RCM), it presents real-time flood hydrograph predictions using the genetic algorithm (GA-based RCM) model. In addition, it presents how to make real-time flood hydrograph predictions using the artificial neural network (ANN). The chapter briefly introduces the basics of GA and details how to calibrate and validate the GA-based RCM model using measured real-time flood hydrographs. Similarly, after giving the basics of ANN, it shows how to train and test the ANN model using measured hydrographs. Real hydrograph simulations by the RCM, GA-based RCM, and ANN are presented, and merits of each model are discussed. © 2023 Elsevier Inc. All rights reserved.Conference Object Citation - Scopus: 2Lighting Quality and Work Performance Based on Glazing Types and Dynamic Led Lighting(IEEE, 2022) Köse, Fatma Büşra; Tayfur, Gökmen; Duran, Hasan Engin; Kazanasmaz, Zehra TuğçeThe combination of daylight characteristics and LED lighting quantities determines offices' visual environment. Lighting conditions can influence office workers' health and work performance. This study is an experimental one containing lighting measurements in two offices, subjective performance tests, and questionnaires to find out how work performance, lighting preferences, and satisfaction with lighting quality modify in terms of various glass types and dynamic LED lighting quantities. Glass types have strong impacts on contrast tests on paper and luminance which are corresponding to work performance. Regarding lighting quality, it strongly relates to the homogeneity of light, the impression of artificial light and the perception of objects' textures and color, contrast balance between paper and the surrounding. When the glass was modified in offices, we observed that participants preferred to change the CCT setting of LED by remote control, and in relation to that the eye-level illuminance and SPDs showed significant changes. So, the findings depicted the importance of the choice of glass types concerning LED lighting settings in terms of the above variables.Article Citation - WoS: 10Citation - Scopus: 11Meteorological Drought Analysis for Helmand River Basin, Afghanistan(TMMOB İnşaat Mühendisleri Odası, 2022) Alami, Mohammad Musa; Tayfur, GökmenThis study evaluates drought at Lashkargah, Farah, Adraskan, and Gardandiwal stations in Helmand River Basin (HRB) in Afghanistan to determine appropriate drought indices for the basin. Thirty seven years of monthly recorded precipitation data from 1979 to 2015 are employed with different drought index (DI) methods which include the Standardized Precipitation Index (Normal-SPI, Log-SPI, and Gamma-SPI), the Percent of Normal (PN), and the Deciles. All the methods are applied to the annual long term precipitation data. The log-SPI and the gamma-SPI predict extreme drought conditions, whereas, the normal-SPI determines wet and less dry conditions. The results emphasize that the PN and the Deciles methods predict more drought years in comparison to the SPI methods. The Deciles method shows longer period of extreme and severe drought than other methods. The five methods indicate various drought intensities in 1985, 1987, 1994, 1997, 1999, 2000, 2001, 2002, 2003, and 2004 at all the stations. The extreme drought condition in 2001 at all the stations confirms to the recorded drought reports for the same region. It is noted that since the log-SPI and the gamma-SPI capture the historical extreme and severe drought periods successfully, these are recommended as the drought monitoring indices for Helmand River Basin.Article Citation - WoS: 2Citation - Scopus: 3Rijit Gövdeli Bitkilerin Neden Olduğu Manning Katsayısının Araştırılması(Turkish Chamber of Civil Engineers, 2015) Yerdelen, Cahit; Mertsoy, Mesut; Tayfur, GökmenDoğal akış yatakları veya yapay taşkın yataklarında akım incelenirken bitkilerin sebep olduğu direnç kuvvetinin bir eşitlik yardımıyla belirlenmesi önemli bir konudur. Manning, Chezy, Darcy-Weisbach gibi eşitliklerde kullanılan direnç katsayıları, daha çok çeper özelliklerini temsil eden deneysel katsayılardır. Açık kanal şartlarında var olan veya akış kesitini kontrol etme amaçlı insanoğlunun planladığı bitkisel akış alanlarında akım hızının, su derinliğinin veya akış hacminin ampirik olarak çözülmesi planlama ve işletme süreçlerini olumlu yönde etkileyecektir. Bu çalışmada, akış kesitinde oluşacak direnç kuvvetinin, bitkilerin ve akışın fiziksel şartlarına bağlı olarak nasıl değiştiği incelenmiş ve doğrusal olmayan bir regresyon modeli önerilmiştir.Article Citation - WoS: 8Citation - Scopus: 8Estimation Groundwater Total Recharge and Discharge Using Gis-Integrated Water Level Fluctuation Method: a Case Study From the Alasehir Alluvial Aquifer Western Anatolia, Turkey(Springer Verlag, 2020) Şimşek, Celalettin; Demirkesen, Ali Can; Baba, Alper; Kumanlıoğlu, Ahmet; Durukan, Seda; Aksoy, Niyazi; Tayfur, GökmenThe estimation of groundwater recharge is an essential process for hydrogeological study. Realistic determination approach is crucial for assessing groundwater potential in an aquifer system and estimating of groundwater levels and/or changes in dry periods. Based on these matters, we employ a GIS-integrated groundwater level fluctuation method to determine the groundwater recharge for a hydrological period in the Alasehir alluvial aquifer (W. Anatolia). The method basically takes into account both increasing and decreasing of the groundwater levels due to the recharge and discharge mechanisms in the aquifer. In this study, 16 pumping and monitoring wells were drilled with a total depth of 1300 m, and water level data loggers were installed into the monitoring wells to determine the groundwater level changes. The spatial distribution of the monthly groundwater level change map was multiplied by the aquifer storage distribution map and then the accurate water volume is calculated by using the 3-D spatial analysis. According to our evaluation in the aquifer, positive volume change of the groundwater is 187 hm(3) in a year, which is considered as a recharge value of groundwater. It is concluded that the GIS-integrated water table fluctuation method gave rise to estimate the total recharge amount of the groundwater in the Alasehir aquifer. The total groundwater recharge indicates that total inflow in the aquifer from precipitation, leakage from surface water and irrigation waters. It can be stated that the recharge estimation of groundwater in a surficial aquifer, like the Alasehir aquifer, is fairly easy using the GIS-integrated water table fluctuation method.Article Citation - WoS: 4Citation - Scopus: 3Baraj Yıkılması Sonrası İki Boyutlu Taşkın Yayılımının Yerleşim Bölgeleri için Modellenmesi(Turkish Chamber of Civil Engineers, 2017) Elçi, Şebnem; Tayfur, Gökmen; Haltaş, İsmail; Kocaman, BülentHer ne kadar baraj yıkılması nadiren gerçekleşse de, aniden yıkılan bir barajın taşkın dalgasının mansapta bulunan yerleşim bölgelerinde etkisi felaketle sonuçlanabilmektedir. Bu sebeble muhtemel bir baraj yıkılmasının sonuçlarını öngörmek risk yönetimi açısından gereklidir. Bu çalışmada baraj yıkılması sonucunda oluşan taşkın dalgasının tahmini ve mansapta ilerlemesinin analizine yönelik bir yaklaşım sunulmuştur. Sunulan yaklaşım, barajların aniden yıkılma varsayımı ile baraj haznesindeki su hacminin bir-boyutlu model ile dar bir vadi boyunca ötelenmesini ve ötelenmiş hidrograf sınır şartı kabul edilerek mansabında yerleşim bölgeleri yer alan iki ayrı çalışma alanında taşkın dalgasının iki boyutlu yayılımının modellenmesini içermektedir. Önerilen yaklaşım mansabında Eskişehir bulunan Porsuk Barajı ile mansabında İstanbul olan Alibey Barajına uygulanmıştır.Article Citation - Scopus: 35Experimental Investigation of Screens as Energy Dissipaters in Submerged Hydraulic Jump(Türkiye Klinikleri Journal of Medical Sciences, 2014) Sadeghfam, Sina; Akhtari, Ali Akbar; Daneshfaraz, Rasoul; Tayfur, GökmenThis study investigated the effectiveness of screens as energy dissipaters in small hydraulic structures using physical experiments. In the experimental design, the Froude number, screen arrangements, and screen porosity were the major controlling parameters. The experiments covered a range of Froude numbers between 2.5 and 8.5, screen porosity of 40% and 50%, and gaps of double screens between 1 and 5 cm. The main goal of this study was investigation of the screens creating submerged hydraulic jumps. The flow depth was digitally measured in order to perceive the turbulences and validate the results of energy dissipation against those of the methods in the literature. The experimental results show the importance of each parameter on the screen performance. The screens with double arrangement with the imposed hydraulic jump dissipated more energy. The gaps of the double arrangement had an insignificant effect on energy dissipation. The double screen with porosity of 40% had the best performance. Since the Froude number was found to be the most effective parameter, quadratic equations as a function of this number were fitted to the experimental results with high R2 and very low RMSE values. The quadratic equations can be employed as interpolators and/or extrapolators.Article Citation - WoS: 2Citation - Scopus: 2Ampirik Yöntemlerle Gediz Nehri için Askıda Katı Madde Yükü Tahmini(Turkish Chamber of Civil Engineers, 2011) Ülke, Aslı; Özkul, Sevinç; Tayfur, GökmenIt is essential to predict suspended sediment load for understanding river morphology, design of dams, water supply problems, management of reservoirs and determination of pollution levels in rivers. The suspended sediment load can be determined by means of several methods such as direct measurements at the sediment gauging stations, sediment rating curve, son modeling methods, and empirical methods which are based on experimental works. The objective of this study is first to determine the best empirical method for Gediz river and then to improve the determined method by genetic algorithm (GA). It is seen that the GA improved Brooks method can be used for Gediz River Basin. In addition, this method was compared with other soft computing (ANN, ANFIS) methods and its performance is found to be as good as them.