particle swarm algorithm

Climate change causes changes in the flow of rivers by causing changes in temperature and precipitation. Therefore, river flow simulation is important as a prerequisite for some environmental and engineering issues. In the current research, the effect of climate change on the Mahabad’s river flow in the future periods (2045-2026) was predicted using machine learning models. First, two input scenarios were compiled, in which the first scenario included temperature and precipitation parameters and the second scenario included temperature, precipitation, and flow parameters one month ago. In the following, the performance of two ANN and ANN-PSO models in estimating the flow rate in the base period (1992-2014) was compared to select the best scenario and the best model for predicting the flow in the future period under the three scenarios SSP1.26, SSP2.45 and SSP5.85 of the CMIP6. The results of the error evaluation criteria showed that the ANN-PSO model makes the best estimation of the river flow using the second scenario and with the criteria (NSE=0.77, RMSE=6.4 MCM, MAE=3.4 MCM for the test data) and it was chosen to predict the flow in the future period (2026-2045). The results of investigating the effect of climate change on each of the meteorological parameters showed that climate change causes an increase in temperature and creates a fluctuating pattern in precipitation. The results of the climate change survey on flow showed that under the SSP1.26 scenario, there will not be much changes in flow in almost months, but in the SSP2.45 and SSP585 scenarios, there will be an increase in the discharge in December, and in May and April, the greatest decrease in discharge will be (16.50 MCM) and (13.33 MCM) respectively.

Cropping pattern optimization is an important strategy in the optimal use of water in agriculture. The present study attempted to develop and evaluate four hybrid models based on maximizing economic return rate and minimizing risk based on risk indices including variance (MVar model), semi-variance (MSVar model), absolute value deviation from mean (MADev model) and conditional value at risk (MCOVaR model). The MCOVaR model is governed by observing the rules, which at a selective confidence level allows determining the best cropping pattern scenario with selective return rate and the lowest risk that can be measured in the decision-making stage. The data used are related to the downstream irrigation network of Ardabil Yamchi Dam and for the 1397-98 crop year. The development of the model in MATLAB is based on nonlinear programming and optimization problem solving using particle swarm algorithm in a multi-objective solution. The highest correlation coefficient in regression of the models with Fourier equation was R2=0.9997 with accuracy (RMSE=0.0011) for MADev model, The results showed that the highest yield of 0.31 belonged to potatoes with a maximum risk of 58% and the lowest yield of 0.13 belonged to the maize plant with a maximum risk of 63%. By calculating 50 scenarios of the best possible cropping patterns in terms of satisfying the target functions and governing conditions, the pareto front of each model was drawn and the table of system income values for risk levels of 20% and 30% was extracted and presented. The results obtained in all models indicate an increase in economic efficiency by increasing the risk level of the system in selecting the optimal cropping pattern and this increase in MADev model is more steep than other models and increasing risk-taking leads to increasing the area under cultivation of plants with more water consumption.

Monitoring network optimization is a decision making process for the best combination of available stations. Due to economic considerations and reduction of monitoring costs ، the optimization approach in this study is to reduce monitoring stations without reducing the amount and accuracy of the information obtained. In this study, an optimal design of groundwater quality monitoring network was carried out with the help of an optimization model in the Neishabour plain aquifer. The optimization of the wells network was accomplished by a Multi Objective Particle Swarm Optimization (MOPSO) algorithm. Two objectives containing of minimizing the root mean square error (RMSE) and the number of wells was applied in current research. Kriging interpolation was used for calculating groundwater chlorine concentration values and compared with observation values. As a result of this research was presented a Pareto front exctracted from MOPSO showing the number of wells against their corresponding RMSE, which could be a guide for the design of a groundwater quality monitoring network. The outcome showed that the sampling wells can be reduced to 58 percent with a minimum error increase (all 50 wells in base network with zero error may be reduced to 21 with chlorine concentration error of 13.57 mg/l) in the Neishabour aquifer. Also, the position of these wells was considered as the optimal position.

Due to the limited surface water resources and reservoir capacity of dams, scientific management and optimal utilization policy of reservoirs is essential and vital in meeting the water requirements. Considering the importance and utilization of water resources and the optimal allocation of this scarce resource among different uses in the Sistan region, it seems necessary to establish a plan to achieve this goal. In the studied area and in the country, so far, an investigation into the optimal allocation of water with the application of advanced PSO algorithm for optimization of semi-Sistan reservoirs has not been used. Therefore, in the present study, the optimal allocation of water resources in the Chah-Nimeh reservoirs under three management scenarios (scenario of stabilization of micro-organisms, agricultural development and transfer of second drinking water from reservoirs to the district of Zahedan) using the metamorphic technique of congestion Particles (PSO) have been investigated. particle swarm optimization method or abbreviated mass optimization (PSO) is a population based stochastic optimization algorithm that simulates the social behavior of birds Group is inspired. In the mass optimization algorithm of particles, there are organisms that they are called particle and are spilled in the search space of a function that is intended to minimize (or optimize) its value. Each particle calculates the value of the target function in the position of the space in which it is located. In this research, the algorithm was used to allocate optimal water resources. The objective function in this research is to optimize and maximize the amount of water supply. Also, the constraints are related to the objective function, the systematic constraints, the constraints and limitations of the algorithm and the constraints and limitations of the reservoirs in the region. According to the results, the optimum release rate in 1995 (first year) was 39.35 million cubic meters, with the demand of 98.31 million cubic meters, which did not meet the required amount of 72.91 million cubic meters. The comparison of the last four years shows that in the year 29, lack of supply was less than the next three years. The scenario of stabilization of the microstats in the study area was considered as a serious project. The results of this scenario showed that the application of the algorithm used can properly optimize the allocation of water resources. According to the results, it is suggested that ultra-modern modeling can achieve more optimal allocation with the minimum error in the target function.

Exploitation of dam reservoirs is one of the major problems in the management of water resources. In this research, Crow Search Algorithm (CSA) was used for the first time to manage the operation of reservoirs. Also, the results related to the exploitation of the single-reservoir system of Shahid-Rajaei dam, located in Mazandaran province, northern Iran, which meets the downstream water demands, were compared to those obtained by applying the Particle Swarm and Genetic algorithms. Time reliability, volume reliability, vulnerability and reversibility indices, and a multi-criteria decision-making model were used to select the best algorithm. The results showed that the CSA obtained results close to the problem’s absolute optimal response, such that the average responses in the Crow, Particle Swarm and Genetic Algorithms were 99, 75 and 61 percent of the absolute optimal response, respectively. Besides, except for the time reliability index, the CSA had a better performance in the rest of the indices, as compared to Particle Swarm and Genetic Algorithms. The coefficient of variation of the obtained responses by CSA was 14 and 16 times smaller than the Genetic and Particle Swarm Algorithms, respectively. The multi-criteria decision-making model revealed that the CSA was ranked first, as compared to the other two algorithms, in the Shahid-Rajaei Reservoir's operation problem.