Evaluation and modeling of streamflow data: entropy method, autoregressive models with asymmetric innovations and artifical neural networks

Download

index.pdf

Date

2005

Author

Şarlak, Nermin

Metadata

Show full item record

Item Usage Stats

206
views

90
downloads

In the first part of this study, two entropy methods under different distribution assumptions are examined on a network of stream gauging stations located in Kizilirmak Basin to rank the stations according to their level of importance. The stations are ranked by using two different entropy methods under different distributions. Thus, showing the effect of the distribution type on both entropy methods is aimed. In the second part of this study, autoregressive models with asymmetric innovations and an artificial neural network model are introduced. Autoregressive models (AR) which have been developed in hydrology are based on several assumptions. The normality assumption for the innovations of AR models is investigated in this study. The main reason of making this assumption in the autoregressive models established is the difficulties faced in finding the model parameters under the distributions other than the normal distributions. From this point of view, introduction of the modified maximum likelihood procedure developed by Tiku et. al. (1996) in estimation of the autoregressive model parameters having non-normally distributed residual series, in the area of hydrology has been aimed. It is also important to consider how the autoregressive model parameters having skewed distributions could be estimated. Besides these autoregressive models, the artificial neural network (ANN) model was also constructed for annual and monthly hydrologic time series due to its advantages such as no statistical distribution and no linearity assumptions. The models considered are applied to annual and monthly streamflow data obtained from five streamflow gauging stations in Kizilirmak Basin. It is shown that AR(1) model with Weibull innovations provides best solutions for annual series and AR(1) model with generalized logistic innovations provides best solution for monthly as compared with

Subject Keywords

Engineering design.

URI

http://etd.lib.metu.edu.tr/upload/3/12606135/index.pdf
https://hdl.handle.net/11511/15151

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

A study on heat transfer inside the wellbore during drilling operations Apak, Esat Can; Özbayoğlu, Evren; Department of Petroleum and Natural Gas Engineering (2006) Analysis of the drilling fluid temperature in a circulating well is the main objective of this study. Initially, an analytical temperature distribution model, which utilizes basic energy conservation principle, is presented for this purpose. A computer program is written in order to easily implement this model to different cases. Variables that have significant effect on temperature profile are observed. Since the verification of the analytical model is not probable for many cases, a computer program (ANSYS...
Development of helical tubular reactor for hydrogen producing photosynthetic bacteria Sarı, Süleyman; Eroğlu, İnci; Department of Biotechnology (2007) Photobiological hydrogen production from organic materials occurs with the help of illumination and under aerobic conditions within photobioreactors. Novel designs are needed in order to increase the light conversion efficiency and to improve the biological hydrogen production. In this thesis, purple non sulfur bacteria Rhodobacter sphaeroides O.U. 001 was employed as the hydrogen producing microorganism. Two different types of photobioreactors, namely oscillatory helical photobioreactor and recycling helic...
RECONSTRUCTION OF PERMITTIVITY AND CONDUCTIVITY PROFILES OF A DIELECTRIC SLAB IN THE TIME DOMAIN BY DESCENT METHODS ONDER, M; Kuzuoğlu, Mustafa (Institution of Engineering and Technology (IET), 1992-10-01) An optimisation approach is presented for the problem of reconstructing the permittivity and conductivity profiles of a dielectric slab from the reflected and transmitted field data. The problem is treated as an optimal control problem where the norm of the difference of measured and calculated boundary data is minimised subject to the state equation governing the system. The original constrained optimisation problem is reduced to the evaluation of stationary points of an augmented functional which is obtai...
Optimization of Speed Control Hump Profiles BAŞLAMIŞLI, SELAHATTİN ÇAĞLAR; Ünlüsoy, Yavuz Samim (2009-05-01) In this study, the goal attainment method is implemented for the optimization of speed control hump profiles. Basic dimensions for a number of hump profile functions are optimized for single vehicles classified in five categories and for a specified distribution of these vehicles. Objective functions are selected as combinations of the longitudinal and vertical acceleration components at pre-specified points on the vehicle body. The main objective is to minimize vehicle response functions below the hump cro...
Shape Optimizations of Metallic Sheets for Improved Near-Zone Scattering, Reflection, and Focusing Characteristics Altinoklu, Askin; Ergül, Özgür Salih (2017-10-12) We consider full-wave analysis and optimizations of metallic sheets to obtain desired electromagnetic responses in the near-zone field intensity and power density distributions. Given a metallic sheet of finite size, deformations are applied to achieve diverse scattering and reflection characteristics, particularly focusing and collecting electromagnetic power at different locations. Optimizations are performed by employing genetic algorithms in a multigrid scheme on the discretized geometry, while each tri...

Citation Formats

N. Şarlak, “Evaluation and modeling of streamflow data: entropy method, autoregressive models with asymmetric innovations and artifical neural networks,” Ph.D. - Doctoral Program, Middle East Technical University, 2005.