WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7150

Browse

Filters

2010 - 201922020 - 20256

Settings

Author: search.filters.author.Tayfur, GokmenHas files: Yes

Search Results

Now showing 1 - 8 of 8
  • Article
    Citation - WoS: 7
    Projektiranje Nasipa Zeljezničkih Pruga Primjenom Neuronskih Mreža
    (Croatian Soc Civil Engineers-hsgi, 2013) Tayfur, Gokmen; Egeli, Isfendiyar
    The main requirement in the design of high-speed railway embankments are low values of total differential settlements. The use of cement stabilized layers in embankments, as compared to non-stabilized layers that are now most often in use, is analysed in the paper. Different cement proportions and different water/cement ratios for stabilized layers are considered. It was established that the use of cement stabilized layers in embankments can greatly reduce thickness of individual layers, while also reducing settlement. The research was conducted using the feed forward neural network.
  • Article
    In-Depth Analysis of Drought Trend in Semiarid Saïs Plateau and Middle Atlas Region in Morocco
    (Springer int Publ Ag, 2025) Qadem, Zohair; Tayfur, Gokmen; Kankal, Murat
    This study explores the spatiotemporal properties of droughts and their evolution in the semiarid Sa & iuml;s Plateau and the Middle Atlas regions in Morocco. The methodology includes the analysis of 36 years of precipitation data recorded at 16 meteorological stations, the use of the standardized precipitation index (SPI) at different temporal scales of short term (1 and 3 months), medium term (6 months), and long term (12 and 24 months) to capture historical droughts, and the application of the Mann-Kendall test to assess the drought trends. The wet and dry periods in the Sa & iuml;s Plateau and Middle Atlas regions are almost evenly distributed, with 65% in the "near-normal" condition. The "extremely dry" period, with a value of 1%, was lower than the "extremely humid" period (1.65%). There is no topographically and climatically significant difference between the Sa & iuml;s Plateau and the Middle Atlas in terms of droughts, which are found to decrease over time in both regions. The results of Mann-Kendall test reveal that the short-term trends are generally positive, except at the Boulemane station (- 0.06 for SPI-1, - 0.13 for SPI-3). The long-term precipitation increases in the Middle Atlas region, particularly at the Ait Khabach (0.33 for SPI-24) and the Imouzzer (0.36 for SPI-24) stations. On the Sa & iuml;s Plateau, the trends are positive at the stations of Fez City (0.16 for SPI-24) and Dar Elarsa (0.27 for SPI-24). Significant trends are more pronounced at longer time scales.
  • Article
    Numerical Study of Breaching at Upper Parts of Homogenous Earthen Dams
    (Springer Heidelberg, 2025) Dumlu, Emre; Guney, Mehmet Sukru; Okan, Merve; Ozden, Guerkan; Tayfur, Gokmen
    In this study, time-dependent finite element analyses of the breaching process in two homogenous earth-fill dams were performed using the finite element method. Breaching was initiated at the middle and corner sections of the upper part of the dam bodies. The numerical results were compared with the findings of the experiments realized on dams 60 cm high, 2 m wide at bottom, 20 cm wide at crest with 1 V:1.5H side slopes at upstream and downstream faces. This numerical study combines time-dependent hydraulic gradient distributions and groundwater flows to assess breach areas, velocities, and flow rates. A Python algorithm was integrated with the Jupyter console, allowing the simulation of the breach mechanism in multiple runs to determine breach parameters. Both numerical and experimental analyses revealed that the dams were exposed to backward erosion, starting at the downstream side of the dam and progressing inward. The compatibility between experimental and numerical results was sought by means of the parameters RMSE, MAE and the statistical performance of the numerical approach was evaluated by using RSR, NSE, and PBIAS. A fairly good agreement was obtained between the experimental and numerical results.
  • Correction
  • Conference Object
    Decoding and Predicting the Attributes of Urban Public Spaces With Soft Computing Models and Space Syntax Approaches
    (Ecaade-education & Research Computer Aided Architectural design Europe, 2023) Yonder, Veli Mustafa; Dogan, Fehmi; Cavka, Hasan Burak; Tayfur, Gokmen; Dulgeroglu, Ozum
    People spend a considerable amount of time in public spaces for a variety of reasons, albeit at various times of the day and during season. Therefore, it is of utmost importance for both urban designers and local authorities to try to gain an understanding of the architectural qualities of these spaces. Within the scope of this study, squares and green parks in Izmir, the third largest city in Turkey, were analyzed in terms of their dimensions, landscape characteristics, the quality of their semi-open spaces, their landmarks, accessibility, and overall aesthetic quality. Using linear predictor, general regression neural networks, multilayer feed-forward neural networks (2-3-4-5-6 nodes), and genetic algorithms, soft computing models were trained in accordance with the results of the conducted analyses. Meanwhile, using space syntax methodologies, a visibility graph analysis and axial map analysis were conducted. The training results (i.e., root mean square error, mean absolute error, bad prediction rates for testing and training phases, and standard deviation of absolute error) were obtained in a comparative table based on training times and root mean square error values. According to the benchmarking table, the network that most accurately predicts the aesthetic score is the 2-node MLFNN, whereas the 6-node MLFN network is the least successful network.
  • Article
    Citation - WoS: 4
    Citation - Scopus: 3
    Assessment of Soil Erosion and Sediment Delivery Ratio in the Arghandab Catchment, Kandahar Province, Afghanistan by Using Gis-Based Rusle Method
    (Taylor & Francis Ltd, 2024) Ansari, Ahmad; Tayfur, Gokmen; Mohammadi, Shahin
    A significant proportion of Arghandab Catchment in Kandahar Province, Afghanistan has been under potential degradation threat due to soil erosion. This study assessed the extent of soil erosion and estimated the sediment delivery ratio (SDR) in the catchment by employing the Revised Universal Soil Loss Equation (RUSLE), utilizing the Geographic Information System (GIS) and the Remote Sensing (RS) techniques. Data, related to rainfall erosivity (R factor), soil erodibility (K factor), slope length and steepness (LS factor), cover management (C factor), and support practices (P factor), employed for the RUSLE model were processed using the GIS tools and R-Studio software. Average RUSLE factor values estimated in the studied area ranged from 51.8 to 124 MJ mm ha-1 h-1 year-1, 0.03725 t ha h ha-1 MJ-1 mm-1, 9.2, 0.445, and 0.75 for R, K, LS, C, and P factors, respectively. The results revealed that the average annual soil loss from the catchment was 6.81 t ha-1 yr-1, ranging from 0.002 t ha-1 yr-1 in the flat areas up to 94.7 t ha-1 yr-1 in the hilly and mountainous regions. Soil classes of slight, moderate, high, very high, severe, and very severe covered areas of 20.1% (263,542.3 ha), 12.2% (160,286.5 ha), 22.8% (298,740.6 ha), 20.3% (265,546.8 ha), 17.6% (231,224.4 ha) and 6.9% (90,879.9 ha), respectively. The computed SDR for Dahla Reservoir located in the catchment was found to be in between 24.2% and 36%. LS factor was identified as the most crucial variable associated with soil erosion. The findings from this study can be applied when designing effective conservation strategies in the management of erosion and water management.
  • Article
    Citation - WoS: 7
    Citation - Scopus: 8
    A Joint Evaluation of Streamflow Drought and Standard Precipitation Indices in Aegean Region, Turkey
    (SPRINGER BASEL AG, 2023) Gülmez, Ayşe; Mersin, Denizhan; Vaheddoost, Babak; Safari, Mir Jafar Sadegh; Tayfur, Gokmen
    Water is an invaluable substance that ensures the life cycle and causes hydrologic events worldwide. Water deficit, also known as drought, is a naturally occurring disaster that affects the hydrometeorologic and/or climatic responses in time and space. In this study, the meteorologic and hydrologic droughts in Buyuk Menderes, Kucuk Menderes, and Gediz basins in Turkey are investigated. The streamflow drought index (SDI) and standard precipitation index (SPI) are used considering different time windows. To achieve this, the monthly streamflow at Cicekli-Nif, Besdegirmenler-Dandalas, Bebekler-Rahmanlar, and Kocarli-Koprubasi hydrometric stations together with monthly precipitation at 14 meteorologic stations during 1973-2020 (47 years) are used. The SDI and SPI with 1, 3, 6, and 12 months moving average are then used to express the association between the meteorologic and hydrologic droughts in the basin. Results showed that the SDI depicts no abnormal situations, while the SPI rates in the 1980s and 2010s indicated severe droughts. It was concluded that the inner parts of the basins are prone to frequent droughts, and there is a concordance between SPI and SDI patterns at the basin level. However, minor discrepancies between SPI and SDI do exist and probably originated from temporal delays and water abstraction.
  • Article
    A Fuzzy Logic Model To Classify Design Efficiency of Nursing Unit Floors
    (Yıldız Teknik Üniversitesi, 2010) Kazanasmaz, Tugce; Tayfur, Gokmen
    This study was conducted to determine classifications for the planimetric design efficiency of certain public hospitals by developing a fuzzy logic algorithm. Utilizing primary areas and circulation areas from nursing unit floor plans, the study employed triangular membership functions for the fuzzy subsets. The input variables of primary areas per bed and circulation areas per bed were fuzzified in this model. The relationship between input variables and output variable of design efficiency were displayed as a result of fuzzy rules. To test existing nursing unit floors, efficiency output values were obtained and efficiency classes were constructed by this model in accordance with general norms, guidelines and previous studies. The classification of efficiency resulted from the comparison of hospitals.