نتایج جستجو برای: nonlinear artificial neural network and hybrid models is advantaged for drought forecasting. this paper presents the performances of autoregressive integrated moving average (arima)

تعداد نتایج: 26091259  

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...

پایان نامه :0 1392

nowadays in trade and economic issues, prediction is proposed as the most important branch of science. existence of effective variables, caused various sectors of the economic and business executives to prefer having mechanisms which can be used in their decisions. in recent years, several advances have led to various challenges in the science of forecasting. economical managers in various fi...

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...

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: :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...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شهید چمران اهواز - دانشکده مهندسی علوم آب 1393

drought is transient phenomenon , slow , repetitive and integral part of the climate of each region. drought begins with a substantial reduction in precipitation over the long-term average rainfall and over time, reduced soil moisture and surface and ground water resources will continue to decrease. this phenomenon is the most important in bakhtegan basin because of its importance in strategic ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس - دانشکده علوم انسانی 1389

rivers and runoff have always been of interest to human beings. in order to make use of the proper water resources, human societies, industrial and agricultural centers, etc. have usually been established near rivers. as the time goes on, these societies developed, and therefore water resources were extracted more and more. consequently, conditions of water quality of the rivers experienced rap...

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...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه علامه طباطبایی 1390

over the past decades a number of approaches have been applied for forecasting mortality. in 1992, a new method for long-run forecast of the level and age pattern of mortality was published by lee and carter. this method was welcomed by many authors so it was extended through a wider class of generalized, parametric and nonlinear model. this model represents one of the most influential recent d...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس - دانشکده مهندسی 1387

abstract this paper discusses several commonly used models for strategic marketing¹ including market environmental analysis methods (i.e. swot and pest analysis) and strategic marketing tools and techniques (i.e. boston matrix and shell directional policy matrix)and shows how these models may help a firm to achieve its strategic goals. at first, the main reason for doing this research is de...

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