Yazar "Yildiz O." seçeneğine göre listele

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  • Küçük Resim
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    An investigation of the effect of drainage density on hydrologic response
    (2004) Yildiz O.
    The sensitivity of streamflow simulations to the drainage density of river basins was investigated. A physically based spatially distibuted hydrologic model was used in the model experiments. The hydrologic model was applied to the Monongahela river basin in the United States of America for the simulation of 1988 and 1993 hydrologic regimes for selected periods between April and July. Model simulations of streamflows for 3 different drainage density scenarios (0.2, 0.24 and 0.38 km-1) were compared against the observations. Evaluation of the model results indicated that the hydrologic model response changes significantly for the prescribed drainage densities. In general, the hydrologic model overestimated the stream discharges in response to an increase in drainage density. This outcome was attributed to an increase in the number of channel pixels, and thus an increase in the subsurface flow contribution to the total streamflow. © TÜBITAK.
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    Prediction of wind speed and power in the Central Anatolian region of Turkey by adaptive neuro-fuzzy inference systems (ANFIS)
    (2006) Çam E.; Yildiz O.
    An adaptive neuro-fuzzy inference systems (ANFIS) model was used for predicting regional average wind speed and power values in the Central Anatolian region of Turkey. In model development, longitude, latitude and altitude of wind stations and wind speed measurement height were taken as input variables, while wind speed and power values were taken as output variables for 4 different surface roughness characteristics. After a successful learning and training process the proposed model produced reasonable mean errors ranging from 0.19% to 2.89% and negligible root mean square errors in training and testing wind speed and wind power data. Overall, the study results suggest that the ANFIS model can be used as an effective tool to estimate average wind speed and power values in the study area. © TÜBİTAK.
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    Öğe
    A sensitivity analysis of the HCM 2000 delay model with the factorial design method
    (2006) Akgüngör A.P.; Yildiz O.; Demirel A.
    The sensitivity of the Highway Capacity Manual (HCM) 2000 delay model to its parameters was investigated with the factorial design method. The study results suggest that the arrival flow, the saturation flow, and the green signal time are the main parameters that significantly affect the average control delay estimated by the delay model. Additionally, the multi-parameter interactions of the arrival flow-saturation flow and the arrival flow-green signal time have major effects on the model-estimated average control delay. The study results also demonstrate that the analysis period and the cycle length do not seem to have major effects on the estimation of the average control delay. A further factorial analysis performed to investigate the effect of parameters on the uniform delay showed that the green signal time and the cycle length appeared to significantly affect the uniform delay. © TÜBİTAK.