نتایج جستجو برای: Hybrid models

تعداد نتایج: 1081986  

Journal: :اقتصاد و توسعه کشاورزی 0
رضا مقدسی میترا ژاله رجبی

abstract autoregressive integrated moving average (arima) has been one of the widely used linear models in time series forecasting during the past three decades. recent studies revealed the superiority of artificial neural network (ann) over traditional linear models in forecasting. but neither arima nor anns can be adequate in modeling and forecasting time series since the first model cannot d...

Journal: :iranian journal of fuzzy systems 2011
mehdi khashe mehdi bijari seyed reza hejazi

improving time series forecastingaccuracy is an important yet often difficult task.both theoretical and empirical findings haveindicated that integration of several models is an effectiveway to improve predictive performance, especiallywhen the models in combination are quite different. in this paper,a model of the hybrid artificial neural networks andfuzzy model is proposed for time series for...

Journal: :مهندسی صنایع 0
مهدی خاشعی مهندسی صنایع مهدی بیجاری مهندسی صنایع غلامعلی رئیسی اردلی مهندسی صنایع

time series forecasting is an active research area that has drawn considerable attention for applications in a variety of areas. forecasting accuracy is one of the most important features of forecasting models. nowadays, despite the numerous time series forecasting models which have been proposed in several past decades, it is widely recognized that financial markets are extremely difficult to ...

Mehdi Bijari, Mehdi Khashei

Both theoretical and empirical findings have suggested that combining different models can be an effective way to improve the predictive performance of each individual model. It is especially occurred when the models in the ensemble are quite different. Hybrid techniques that decompose a time series into its linear and nonlinear components are one of the most important kinds of the hybrid model...

Journal: :مرتع و آبخیزداری 0
ام البنین بذرافشان استادیار دانشکدة منابع طبیعی دانشگاه هرمزگان علی سلاجقه دانشیار دانشکدة کشاورزی و منابع طبیعی دانشگاه تهران احمد فاتحی مرج استادیار مرکز تحقیقات کم آبی و خشک سالی در کشاورزی و منابع طبیعی، تهران محمد مهدوی استاد دانشکدة کشاورزی و منابع طبیعی دانشگاه تهران جواد بذرافشان استادیار دانشکدة کشاورزی و منابع طبیعی دانشگاه تهران سمیه حجابی دانشجوی دکتری دانشکدة کشاورزی و منابع طبیعی دانشگاه تهران

drought is random and nonlinear phenomenon and using linear stochastic models, nonlinear artificial neural network and hybrid models is advantaged for drought forecasting. this paper presents the performances of autoregressive integrated moving average (arima), direct multi-step neural network (dmsnn), recursive multi-step neural network (rmsnn), hybrid stochastic neural network of directive ap...

Chahkoutahi, F., Khashei, M.,

Nowadays, electricity load forecasting, as one of the most important areas, plays a crucial role in the economic process. What separates electricity from other commodities is the impossibility of storing it on a large scale and cost-effective construction of new power generation and distribution plants. Also, the existence of seasonality, nonlinear complexity, and ambiguity pattern in electrici...

Improving time series forecastingaccuracy is an important yet often difficult task.Both theoretical and empirical findings haveindicated that integration of several models is an effectiveway to improve predictive performance, especiallywhen the models in combination are quite different. In this paper,a model of the hybrid artificial neural networks andfuzzy model is proposed for time series for...

Journal: :journal of research in health sciences 0
negin-sadat mirian morteza sedehi soleiman kheiri ali ahmadi

background : in medical studies, when the joint prediction about occurrence of two events should be anticipated, a statistical bivariate model is used. due to the limitations of usual statistical models, other methods such as artificial neural network (ann) and hybrid models could be used. in this paper, we propose a hybrid artificial neural network-genetic algorithm (ann-ga) model to predictio...

ژورنال: علوم آب و خاک 2015
بابایی حصار, سحر, عرفانیان, مهدی,

Concerning the drying problem of the Lake Urmia in Iran, so far the relevant scientific research has not been conducted based on watershed management principles. The surface solar radiation (Rs) is one of the key input parameters in most of reference evapotranspiration (ET0) prediction models. In the present research, four solar radiation models were evaluated to predict the monthly-mean values...

Journal: :پژوهش های مدیریت در ایران 0
عادل آذر دانشیار رشته مدیریت، دانشگاه تربیت مدرس، تهران، ایران امیر افسر مربی مدیریت، دانشگاه قم، قم، ایران پرویز احمدی استادیار مدیریت، دانشگاه تربیت مدرس، تهران، ایران

today, stock investment has become an important mean of national finance. apparently, it is significant for investors to estimate the stock price and select the trading chance accurately in advance, which will bring high return to stockholders. in the past, long-term trading processes and many technical analysis methods for stock market were put forward. however, stock market is a nonlinear sys...

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