Showing 2 results for M. Zibaei
B. Najafi, M. Zibaei, M. H. Sheikhi, M. H. Tarazkar,
Volume 11, Issue 1 (spring 2007)
Abstract
In this study wholesale prices of selected crops, namely, tomato, onion and potatoes in Fars province were predicted for various time horizons by using common methods of forecasting and artificial neural networks (ANN). Monthly data from September 1998 to June 2005 period were obtained from Ministry of Jihad-e Agriculture. For comparing different methods data selected from September 1998 to December 2004 were utilized, and latest six - month data were mainly used to monitor the power of prediction. The MAE, MSE and MAPE criteria were used for comparing the ability of different forecasting methods. Results of this study showed that ANN had the lowest error in prediction of prices for one - to three - month periods, but for six - month prediction, all forecasting methods were not statistically different.
F. Fathi, M. Zibaei ,
Volume 14, Issue 53 (fall 2010)
Abstract
Overexploitation of groundwater resource may result in lowering groundwater table at a faster rate due to an imbalance in the total recharge and total withdrawal. In order to make a balance between groundwater exploitation and recharge, the major remedial measures suggested are to strengthen groundwater management, adopt water demand policies, raise water use efficiency, and to increase water supply. Because there is a trade off between farmers’ income and sustainability of groundwater based farming, it is essential that a mathematical model be used to study the effects of withdrawal on farmers' income and sustainability of farm. Such a model can determine optimal crop pattern, suitable irrigation strategies and irrigation methods at different levels of available irrigation water. The relationship between farmers’ income and the withdrawal was then examined using multi-objective programming. The data were obtained from a systematic random sampling method through which 112 farmers were chosen. The percentage decrease in the profit was less than that of the withdrawal for all representative farmers, based on the results obtained from multi-objective method. For example, 8% reduction of groundwater pumping could be imposed without a serious impact on the farmers' income (farmers' income falls about 4%). Finally, the results of this study can help farmers to choose crop patterns, irrigation strategies and irrigation methods in such a way that both farmers’ income and withdrawal are simultaneously optimized and lead to a decrease in extracting groundwater compared to the current status.
