Papers by Bahram Bakhtiari
Wind energy is increasingly being utilized globally, in part as it is a renewable and environment... more Wind energy is increasingly being utilized globally, in part as it is a renewable and environmentalfriendly energy source. The uncertainty caused by the discontinuous nature of wind energy affects the power grid. Hence, forecasting wind behavior (e.g., wind speed) is important for energy managers and electricity traders, to overcome the risks of unpredictability when using wind energy. Forecasted wind values can be utilized in various applications, such as evaluating wind energy potential, designing wind farms, performing wind turbine predictive control, and wind power planning. In this study, four methods of forecasting using artificial intelligence (artificial neural networks with radial basis function, adaptive neuro-fuzzy inference system, artificial neural networkgenetic algorithm hybrid and artificial neural networkparticle swarm optimization) are utilized to accurately forecast short-term wind speed data for Tehran, Iran. A large set of wind speed data measured at 1-h intervals, provided by the Iran Renewable Energy Organization (SUNA), is utilized as input in algorithm development. Comparisons of statistical indices for both predicted and actual test data indicate that the artificial neural networkparticle swarm optimization hybrid model with the lowest root mean square error and mean square error values outperforms other methods. Nonetheless, all of the models can be used to predict wind speed with reasonable accuracy. Keywords Wind energy Á Wind speed forecasting Á Artificial neural networks with radial basis function Á Adaptive neuro-fuzzy inference system Á Artificial neural network-genetic algorithm Á Artificial neural networkparticle swarm optimization hybrid
Ecology and the Environment, Aug 23, 2006
Lysimeter is an important instrument to measure evapotranspiration in the field of irrigation man... more Lysimeter is an important instrument to measure evapotranspiration in the field of irrigation management. The error analysis and calibration of the system is very critical for quality control of collected data. The error sources are many and different. The Kerman weighing electronic lysimeter is a complex of two cultivation tanks, load cells, data logger, and data processing weighing system with 48 m 2 under ground building. In this study, ten-minute interval measured evapotranspiration data were analyzed. The Fourier's series were used to model discrete measured time depended evapotranspiration data. By differentiation of the fitted model the quantity of selected time interval evapotranspiration was computed. By comparing the measured and estimated data the time depended errors were calculated. Computed errors were analyzed, and the statistical distributions of the errors were discussed.
SAGE Open, Jul 1, 2019
Background Malaria is one of the most important parasitic diseases and one of the most important ... more Background Malaria is one of the most important parasitic diseases and one of the most important health problems in a number of countries, particularly countries in tropical and subtropical regions of the world (Azizi, Janghorbani, & Hatami, 2011). Malaria is an acute or chronic infectious disease caused by intracellular protozoan parasites from the Plasmodium genus. The disease is endemic in many countries of the world. Its epidemiologic and entomologic characteristics, the existence of more than 400 species of mosquito vectors, its tendency to drug resistance and the diversity in human sensitivity to this disease, and social, cultural, political, economical, and ecological factors in infected countries make the control of this disease very difficult. Its economic burden has imposed many negative effects on public health (Hatami, 2009). Between 2001 and 2009, the global burden of malaria has increased to more than 34 million (Edlund et al., 2012). According to the latest estimates from the World Health Organization in 2015, there were 214 million new cases (in a range of 149-303 million) of this disease globally and about 438,000 deaths (in a range of 236,000-635,000) have happened, and almost 306,000 deaths occurred in children below the age of 5 years (World Health Organization [WHO], 2015). Iran is considered as an endemic country for malaria. Malaria cases in Iran 2002 to 2007 were, respectively, 0.24, 0.38, 0.20, 0.28, 0.23, and 0.24 per 100,000 people. Most cases are now concentrated in three southeast provinces of 864205S GOXXX10.
Environmental epidemiology, Oct 1, 2019
The association between heat or heat waves and mortality should often be reported in a way that m... more The association between heat or heat waves and mortality should often be reported in a way that makes it sensible by health policymakers. In this study we aimed to assess the effect of heat and heat waves on mortality using attributable risks during 2005-2017. Nine heat waves were defined using a combination of severity and duration of mean daily temperature. Heat wave effects were assessed using added and main effects. Added effects were assessed as a binary variable and main effects were assessed by comparing the median temperature (in heat wave days) to Minimum Mortality Temperature (MMT). The effects of heat, mild heat and extreme heat on mortality were also assessed. Distributed Lag Nonlinear Models were used to assess the relations in a bi-dimensional perspective in which the quadratic b-spline was chosen as the basis function for the dimension of the exposure and the natural cubic b-spline was chosen for lag dimension. The backward perspective was used to estimate the attributable risks. The total mortality attributed to non-optimal temperatures for all days was 1.91% (CI 95%:-6.36, 8.47). The attributable risks (AR) were 2.23%, 2.02% and 0.25% for heat, mild heat and extreme heat days, respectively. AR was more for females and the above 65 years old groups than other groups in heat, mild heat and extreme heat days. While the stronger heat waves defined based on temperature above the 95 and 98 th percentile had a significant attributable risk for total mortality in the added effects; the weaker heat waves (defined based on temperature above of the 90 th percentile (HW1, HW2, HW3) had higher attributable risks, significant for HW1 and HW2,in the main effects. Apparently weaker heat waves show more immediate effects, while stronger heat waves increase mortality over several days.
Highlights Local and external performance of MARS and GEP were assessed for estimating daily ET... more Highlights Local and external performance of MARS and GEP were assessed for estimating daily ET o at six stations with different climates. Two types of scenarios, namely weather data-based and lagged ET o data-based were considered. MARS outperformed the GEP in the weather data-based scenarios. Novel hybrid models were introduced in the lagged ET o data-based scenarios.
Journal of Agricultural Science and Technology, Mar 10, 2011
Finally, we wish to thank all those reviewers for their generous input of time and energy.
Iran-Water Resources Research, Aug 23, 2017
Probable Maximum Precipitation is the greatest depth of precipitation for certain duration. This ... more Probable Maximum Precipitation is the greatest depth of precipitation for certain duration. This study aimed derivation of Depth-Area-Duration (DAD) curves in Fars province for estimating 24-h Probable Maximum Precipitation (PMP24) using two Hershfield statistical approaches and estimating the suitable frequency factor (km). For these purposes the maximum 24-hour precipitation data ((P24)max) with a period of 12-61 years were obtained for 52 stations with long-term data. The km values in the first and second approaches were estimated between 15.3 to 18.4 and 1.6 to 6.8, respectively. Also the corresponding PMP24 were between 280 to 850 and 112 to 380 mm respectively for the two approaches. The PMP24 values were estimated of 50 and 100 year return periods 714 and 771 mm, respectively. Results showed that the km values for the second approach are 75% lower than the km for the first approach. The ratios of PMP24 to (P24)max were obtained in the range of 2.6 to 7.4 and 1.4 to 2.7 respectively for the first and second approaches. Therefore, the second approach is more reliable. Also, the isohyet maps were drawn for PMP for the two approaches over the study area using DEM in GIS. DAD and area reduction curves were determined for each approach. Using these curves it is possible to convert point PMP24 values to areal values in the Fars province.
Desert, 2009
Precipitation and air temperature data, only, are often recorded at meteorological stations, with... more Precipitation and air temperature data, only, are often recorded at meteorological stations, with radiation beingmeasured at very few weather stations, especially in developing countries. Therefore there arises a need for suitablemodels to estimate solar radiation for a completion of data sets. This paper is about an evaluation of eight models foran estimation of daily solar radiation (Q) from commonly measured variables in six synoptic stations of Iran, namely:Mashhad, Kerman, Tabriz, Esfehan, Hamedan and Zanjan using daily rainfall and temperature data for a duration ofthree years of 2000, 2001 and 2002. These stations represent several arid and semiarid sub-climates of Iran as basedon extended-De Martonne climatic classification (semiarid-cold: Mashhad and Tabriz, arid-cold: Esfehan, Kerman,semiarid-extracold: Hamedan and Zanjan). The STATISTICA (ver. 6.0) software was employed for non-linearmultivariate regression. The results indicated that most of the models overestimated in l...
Journal of Water and Soil Science, 2019
One of the most important problems in flood manegment is the damages induced by this phenomenon. ... more One of the most important problems in flood manegment is the damages induced by this phenomenon. Expected annual damage (EAD) is an important index for basin vulnerability against flood. Prediction of flood damages requires the analysis of spatial and temporal risk and must be calculated by the combination of hydrologic, hydraulic and economic models. In this research, the uncertainty was considered in the flood risk analysis. The probability of flood occurrence was calculated by the parabolistic model. By using the river analysis systems software (HEC-RAS) and the geographic information system (GIS) and utilizing the Google-Earth software, the floodplains of Zayande Roud river in Esfahan province were investigated with the return period of 25, 50, 100, 200 and 500 years. The Monte Carlo method was also sed to perform the uncertainty analysis in the proposed method. The logarithmic persion type III was selected as the best distribution of flood. The damage-stage relationship was calculated as well. Based on the uncertinity analysis, the river discharge could be regarded as the major parameter in the uncertainty of EAD.
Journal of Water and Soil Science, 2018
Journal of Injury and Violence Research, 2019
Background: Traffic accidents is one of the main causes of mortality, and has a high impact on ov... more Background: Traffic accidents is one of the main causes of mortality, and has a high impact on overall health and development. Iran is a country with a high prevalence of traffic accidents, and this has been a big concern. In this study, we aimed to study the past decade's trend in mortality due to traffic accident in Kerman, Iran, and its relation with ambient temperature by using Generalized Additive Mixed Models. Methods: Meteorological data, such as temperature, humidity, and wind speed were obtained from the Meteorological Organization of Kerman and traffic mortality data were obtained from the Health Deputy of Kerman University of Medical Sciences. In order to explore the relations, Generalized Additive Mixed Models (GAMMs) were used. Additive models are nonparametric forms of regression models in which the summation of regression coefficients × explanatory variables of a linear regression is replaced by a summation of arbitrary smooth functions of the explanatory variables. Results: About 2900 deaths due to traffic accident occurred from March 2005 until May 2017 in Kerman. The monthly average deaths were 20.01(±14.43) that was more for men than women (15.42 vs 4.58), and was highest in the age 31-60 group. Non-linear effect of time on mortality was significant. There was a negative effect of time on mortality until 2009, while all other confounders were adjusted. After a short-term increasing trend till early 2011, and then a decreasing trend until 2013, an increasing trend was observed again. Holding pollutants, temperature and year (trend effect) stable, mortality tended to be higher for the first half of year, with an increasing slope in the first 3 months of the year. Monthly average temperatures below 13°C was related with increased mortality, but average temperatures around 20°C had no effect on mortality. High temperatures (>23°C) were associated with less mortality. Conclusion: Most traffic accident related deaths occurred in first half of year (spring and summer), and it is probably because of increased inter-city traveling during the summer break. Our results showed that high extreme temperatures have less contribution on the mortality.
Arabian Journal for Science and Engineering, 2014
The aim of this study is to model the daily reference evapotranspiration (ET0) in the Mediterrane... more The aim of this study is to model the daily reference evapotranspiration (ET0) in the Mediterranean region of Algiers, Algeria country, using Adaptive Neuro-fuzzy inference system (ANFIS) and multiple linear regression (MLR) models. Various daily climatic data, i.e. daily mean relative humidity, sunshine duration, maximum, minimum and mean air temperature and wind speed obtained from Dar El Beida weather station, are used as inputs to the ANFIS and MLR models so as to estimate ET0. In order to find the optimal topology of the ANFIS, different architectures were trained and examined and the network with minimum Root Mean Squared Error (RMSE), Mean Absolute Error (MAE) and high Coefficient of Correlation (CC) has been selected as an optimal configuration. A comparison was conducted between the estimates provided by the ANFIS and by MLR. The results showed that ANFIS using the climatic data successfully estimated ET0 and the ANFIS simulated ET0 better than the MLR. Totally 2,193 daily samples were used for training the model, and 730 daily samples for testing and validation of the model. The developed ANFIS model for the ET0 modelling shows good performance with an MAE index in the range of 0.32–0.75, RMSE between 0.41 and 0.75 and the CC in the range of 0.80–0.96, which endows with high performance of predictive ANFIS system to make use for modelling daily reference evapotranspiration (ET0).
The probable maximum precipitation (PMP) and probable maximum flood (PMF) are among the important... more The probable maximum precipitation (PMP) and probable maximum flood (PMF) are among the important measures in designing hydraulic structures. One of the most suitable statistical techniques for estimating PMP is Hershfield method. In this study the maximum 24 hours precipitation was evaluated using 12-53 years of data from 6 rain gauge stations and 1 synoptic station located in Qareh-su basin. For this goal two statistical methods of Hershfield (in two different approaches of standard and revised) were used. For the first approach, frequency factor and the PMP24 were found to vary in the range of 16.98 to 18 and 335.08 to 524.93 mm, respectively. The corresponding values for the second approach was 2.06 to 4.01 and 88.35 to 153.41 mm, respectively. Also the amount of PMP24 with 50 and 100 year return periods using Gumbel distribution were respectively calculated as 579.2 and 613.59 mm in the first approach and 263.69 and 281.7 mm in the second approach. As a criterion independent to...
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Papers by Bahram Bakhtiari