نتایج جستجو برای: neural network models

تعداد نتایج: 1636460  

Journal: :مرتع و آبخیزداری 0
مریم خسروی کارشناسی¬ارشد آبخیزداری، دانشکده منابع طبیعی، دانشگاه تهران، ایران علی سلاجقه دانشیار دانشکده منابع طبیعی، دانشگاه تهران، ایران محمد مهدوی استاد دانشکده علوم فنون دریایی، دانشگاه آزاد اسلامی، واحد تهران شمال‏، ایران محسن محسنی ساروی استاد دانشکده منابع طبیعی، دانشگاه تهران، ایران

it is necessary to use empirical models for estimating of instantaneous peak discharge because of deficit of gauging stations in the country. hence, at present study, two models including artificial neural networks and nonlinear multivariate regression were used to predict peak discharge in taleghan watershed. maximum daily mean discharge and corresponding daily rainfall, one day antecedent and...

Accurate simulation runoff process can have a significant role in water resources management and related issues. The inherent complexity of  this process makes difficult the use of physical and numerical models. In recent years, application of intelligent models is increased a powerful tool in hydrological modeling. The aim of this study was the application of the Gamma test to select the optim...

Journal: :journal of oil, gas and petrochemical technology 2014
gholamreza bakeri maedeh delavar mohammad soleimani lashkenari

in this study, artificial neural network was used to predict the surface tension of 20 hydrocarbon mixtures. experimental data was divided into two parts (70% for training and 30% for testing). optimal configuration of the network was obtained with minimization of prediction error on testing data. the accuracy of our proposed model was compared with four well-known empirical equations. the arti...

Journal: :iranian red crescent medical journal 0
zohreh amiri department of basic sciences, national nutrition and food technology research institute, faculty of nutrition sciences and food technology, shahid beheshti university of medical sciences, ir iran kazem mohammad department of epidemiology and biostatistics, school of public health, tehran university of medical sciences, ir iran +98-2188989126, [email protected] mahmood mahmoudi department of epidemiology and biostatistics, school of public health, tehran university of medical sciences, ir iran +98-2188989126, [email protected] mahbubeh parsaeian department of epidemiology and biostatistics, school of public health, tehran university of medical sciences, ir iran +98-2188989126, [email protected]

results survival probabilities at different times were determined using the cox proportional hazards and a neural network with three nodes in the hidden layer; the ratios of standard errors with these two methods to the kaplan-meier method were 1.1593 and 1.0071, respectively, revealed a significant difference between cox and kaplan-meier (p < 0.05) and no significant difference between cox and...

دهقانی, رضا, قربانی, محمدعلی,

     Electrical conductivity (EC) is an important factor in river engineering, especially studying of river water quality. In this study we studied and evaluated wavelet neural network to predict the electrical conductivity of the Kakareza river (in lorestan), and the results were compared with results of artificial neural network model. For this purpose, hydrogen carbonate, chloride, sulfate, ...

Ever-increasing dependence of human life on energy has made this factor play a critically crucial role either potentially or actively in the functions of various economic sectors of countries. Therefore, the people in charge of any country should try to make exact forecasting of energy consumption and make correct planning about its consumption in a way to optimally control supply-demand parame...

Abdolrasoul Bardideh Amir Hossein Hashemian Behrouz Beiranvand, Eghbal Zand-Karimi Mansour Rezaei

Cox regression model serves as a statistical method for analyzing the survival data, which requires some options such as hazard proportionality. In recent decades, artificial neural network model has been increasingly applied to predict survival data. This research was conducted to compare Cox regression and artificial neural network models in prediction of kidney transplant survival. The prese...

ژورنال: علوم آب و خاک 2019

Estimation of evapotranspiration is essential for planning, designing and managing irrigation and drainage schemes, as well as water resources management. In this research, artificial neural networks, neural network wavelet model, multivariate regression and Hargreaves' empirical method were used to estimate reference evapotranspiration in order to determine the best model in terms of efficienc...

ژورنال: علوم آب و خاک 2020

In this study, we used the ARIMA time series model, the fuzzy-neural inference network, multi-layer perceptron artificial neural network, and ARIMA-ANN, ARIMA-ANFIS hybrid models for the modeling and prediction of the daily electrical conductivity parameter of daily teleZang hydrometric station over the statistical period of 49 years. For this purpose, the daily data for the 1996-2004 period we...

ژورنال: اقتصاد مالی 2017

هدف پژوهش حاضر پیش‌بینی شاخص قیمت بورس اوراق بهادار تهران با استفاده از مدل شبکه عصبی هیبریدی مبتنی بر الگوریتم ژنتیک و جستجوی هارمونی است. مربوط‌ترین نماگرهای تکنیکی به عنوان متغیرهای ورودی و تعداد بهینه نرون در لایه پنهان شبکه عصبی مصنوعی با استفاده از الگوریتم‌های فراابتکاری ژنتیک و جستجوی هارمونی حاصل می‌گردد. مقادیر روزانه شاخص قیمت بورس اوراق بهادار تهران از تاریخ 1/10/91 الی 30/9/94 جهت ...

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