جستجوی مقالات مرتبط با کلیدواژه "شبکه های عصبی" در نشریات گروه "آبخیزداری، بیابان، محیط زیست، مرتع"

  Groundwater is one of the main sources of drinking water, agriculture and industry. It is worth noting that groundwater is considered as reserve resources in some areas, while in other areas it may be used for supplying potable water due to their availability (Daliakopoulos et al., 2005; Nayak et al., 2006). Groundwater analysis is an essential factor in maintaining its access. Modeling and predicting the groundwater level for environmental protection, maintaining the balance of the groundwater system, controlling changes in groundwater levels and protecting the escalation of land subsidence are important. Groundwater management techniques and solutions, and control measurements by researchers and operators to address the long-term problems of land subsidence and groundwater conservation (Affandi and Watanabe 2007; Mohanty et al., 2015). The main aim of this study is to evaluate the accuracy of evolutionary neural network models in the monthly groundwater level estimation. In this study groundwater level, precipitation, evaporation, annual average temperature and effective influence between 1993 and 2016 were used. The purpose of this study is applying neural networks to estimate the groundwater level. To use the neural network, we must optimize the weights and biases of the network. In this research, weights and network biases were obtained using optimization algorithms such as genetic algorithm, particle swarm algorithm, Imperialist Competitive algorithm and ant colony algorithm. Different control parameters have been used for models, and they are compared with each other based on the mean square error and the coefficient of determination. All four models showed the best accuracy for input combinations. Comparison of the results shows that the ANN-GA model has a better performance than the other three models for groundwater level estimation. The advantages of GA are: 1) The nature of the random search of this algorithm in the problem space is in some way a parallel search. Because each of the random-generated chromosomes generated by the algorithm is considered as a new starting point to search for part of the problem-space and searches in all of them simultaneously. 2) Due to the breadth and dispersion of the points to be searched, it yields a satisfactory result in issues of great search space. 3) A kind of random search is targeted and will come from different paths to different answers. In addition, there is no limit to the search and selection of random answers. 4) Because of the competition, the answers and the selection of the best among the population, with a high probability, will reach the optimal level. 5) Its implementation is simple and does not require complex problem-solving procedures. It can be said that this algorithm may be a good candidate for hydrological modeling. Investigating the trend of groundwater level changes in the plain over a period of 22 years shows that from 1993 to 2006, due to excessive withdrawal and droughts, the level of stagnation with a steep slope has fallen. Since then, with the arrival of the water of the Karkheh Dam and the reduction of withdrawal, the groundwater level of the plain table has risen and reaches 14 meters in 2015. Most commonly used methods for training neural networks from descending gradients using back propagation are to calculate real gradients. In recent years, some researchers have developed evolutionary techniques for estimating groundwater level changes, including genetic algorithms (Dash et al. 2010, Jalakamali and Jalakamali 2011), Imperialist competition algorithm (Tahershamsi and Sheikholeslami 2011), particle swarm optimization (Xi et al. 2012, Gaur et al. 2013) and comparing these methods with each other (Kisi et al., 2017). In addition to the above-mentioned models, the ANN-ACOR model was also used. Comparison of the results shows that the ANN-GA model has a better performance than the other three models for estimating groundwater level, which contradicts the results of (Xi, 2012) and (Gaur, 2013), and matches with the research (Jalalkamali, 2011) and (Dash, 2010).

Groundwater system studies to understanding its behavior, requires the exploratory drilling wells, pumping test and geophysical experiments, which can carried out with most cost. For this reason, simulation of groundwater flows by mathematical and computer models, which is an indirect method to groundwater studies, is being spent a few costs. In this research, the efficiency of artificial neural network, fuzzy logic and random forest models has been investigated in groundwater level estimation of Boukan plain. Parameters of precipitation, temperature, flow rate and water level within time period of the previous month were used as input and the water table in each period were selected as output through monthly scale (2006-2017). To evaluating the performance of models, Correlation coefficient, root mean square error and coefficient of mean absolute error were used. The results showed that the Fuzzy Logic and Random Forest models are able to estimate water levels with acceptable accuracy. In terms of accuracy, fuzzy logic model with the highest correlation coefficient (0.96), lowest root mean square error (0.068 m0) and mean absolute error (0.056 m) was recognized as a best the model in the groundwater level prediction.

Groundwater system studies to understanding its behavior, requires the exploratory drilling wells, pumping test and geophysical experiments, which can carried out with most cost. For this reason, simulation of groundwater flows by mathematical and computer models, which is an indirect method to groundwater studies, is being spent a few costs. In this research, the efficiency of artificial neural network, fuzzy logic and random forest models has been investigated in groundwater level estimation of Boukan plain. Parameters of precipitation, temperature, flow rate and water level within time period of the previous month were used as input and the water table in each period were selected as output through monthly scale (2006-2017). To evaluating the performance of models, Correlation coefficient, root mean square error and coefficient of mean absolute error were used. The results showed that the Fuzzy Logic and Random Forest models are able to estimate water levels with acceptable accuracy. In terms of accuracy, fuzzy logic model with the highest correlation coefficient (0.96), lowest root mean square error (0.068 m0) and mean absolute error (0.056 m) was recognized as a best the model in the groundwater level prediction.

Historically, rivers as a major source to supply drinking water and agriculture considered in human societies and very effective in the formation of civilizations. In addition, to this highly important place as valuable ecosystem. At present, most of north of rivers under the influence of human, that cause a variety of change and destruction of ecosystem. Pollution and human interfaces could be the most important factor to pollution caused by waste water of industrial, urban and rural, pollution resulting from disposal of pesticides used in agriculture ,destruction of vegetation construction of dam, and barriers under bridge, blocking the mouth of the river, illegal fishing. Hence, considering the importance of talar river for supply agriculture water, and also pour pollution to in, to identify and assess the river water quality and provide the necessary relationship to estimate pollution and water quality seems. In current study, used 72 samples during the years of 1391 to 1392 from 6 stations namely, weresk, pole sefid, shirgah, Talar,Kiakola and Arabkhil. Then, NSFWQI index was estimated. Then, with apply gene-expression programming and artificial neural network, obtained models for determination of relation between water quality parameters and water quality index with high accuracy. To evaluate the performance of models , statistical parameter such as, root mean square error, mean absolute error, scatter index and correlation coefficient were used. Results showed that the proper functioning of artificial neural networks and planning methods in estimating gene expression index is NSFWQI. The obtained results revealed appropriate performance of that artificial neural and gene-expression programming to estimate NSFWQI index.

Rainfall-runoff models are used in the field of hydrology and runoff estimation for many years, but despite existing numerous models, the regular release of new models shows that there is still not a model that can provide sophisticated estimations with high accuracy and performance. In order to achieve the best results, modeling and identification of factors affecting the output of the model is necessary. In this regard, in present study, it has been tried to identify the factors and estimating the amount of runoff using a variety of methods of artificial intelligence and multiple regression. Then, to evaluate the efficiency of the implemented models and choose the best model, some performance criteria including the correlation coefficient (R), Nash-Sutcliffe coefficient (NSE), the root mean square error (RMSE) and the mean absolute error (MAE) were used . The data used in this study were 9 rainfall events data measured in time period of 2011- 2015 taken from the Khakh watershed of Gonabad. Artificial intelligence models used in this study were: normal feedforward neural networks, feedforward Cascade neural networks, feedbackward Elman neural networks, Adaptive Neuro Fuzzy Inference System (ANFIS) and regression decision tree model (Regerssion Tree) that were implemented in MATLAB software environment and also step multiple regression as statistical methods which was implemented in Minitab software. The results of this study showed that the used statistical and artificial intelligence methods are considered acceptable with almost similar performance and with relatively appropriate accuracy and low error they are able to estimate the amount of runoff. In the meantime, Cascade and normal feedforward neural models with 5 input parameters, presented better performance comparing to the other models, as the performance criteria of R, RMSE, NSE and MAE in these models were the similar values of 0.88 , 0.76, 2 and 1.5, respectively. Overall, the findings indicate better estimations of the artificial intelligence models comparing to the regression model.

Rainfall-runoff modeling is an essential process and very complicated phenomena that is necessary for proper reservoir system operation and successful water resources planning and management. There are different methods like conceptual and numerical methods for modeling of this process. Theoretically, a system modeling required explicit mathematical relationships between inputs and outputs variables. Developing such explicit model is very difficult because of unknown relationship between variables and substantial uncertainty of variables. In this case, Data driven methods which are based on imprecise conditions and evolutionary algorithms have shown capabilities in many nonlinear systems identification and control issues. One of these intelligent methods is Group Method of Data Handling (GMDH). This method produce complex model during the performance evaluation of input and output information sets increasingly. So in this research we have developed a model based on GMDH for rainfall-runoff modeling in Polrood basin located in North of Iran in Guilan province. Results have evaluated using statistical criteria and compared with an artificial neural network (ANN) model. Results have shown the high performance of two methods for rainfall runoff modeling in dairy scales. Based on statistical criteria, experiment results indicates that the GMDH model was powerful tool to model rainfall runoff time series and can be applied successfully in complex hydrological modeling.