The objectives of this research are to propose an approate and efficient model for analyzing rice corn and sugar yields data. A linear mixed model (LMM) with spatial correlation following the conditional autoregressive model (CAR) was adopted. The results show that for rice yields if the amount of rainfall in a harvest season increases 1 mm the yields will decease by 25.74 tons. if the temperature in the harvest season increases 1 Celsius the yields will decease by 212.60 tons and according to the trend the yield will increase by 15.80 tons each year. For sugar cane yields if the amount of rainfall in the harvest season increases 1 mm the yields will decease by 51.35 tons. if the temperature in the harvest season increase 1 Celsius the yields will incease by 121.30 tons and according to the trend the yield will increase by 29.93.80 tons each year. For corn yield if the amount of rainfall in the havest season increases 1 mm the yields will incease by 73.45 tons. if the temperature in he havest season increases 1 celsius the yields will decease by 40.44 tons and according to the trend the yield will increase by 1.74 tons each year.

This research aims to apply the principle of stochastic process for modeling. The parameters are estimated using Bayesian methods. The monthly average real price of paddy rice 15% and yield of paddy rice in Thailand were studied. The price and the yield of paddy rice which are time series data consisting of four components autocorrelation an exponential cumulative distribution function for trend outliers and two different types of seasons: the dummy seasons and Fourier function seasons. Writing algorithms programming in OpenBUGS and evaluating the performance of models from simulation programming in R were conducted. After that Bayesian methods with dummy seasons and Fourier function season were compared using RMSE MSE and MAE as the criteria. The results show that the Bayesian model with an exponential cumulative distribution function for trend and dummy seasons give the lowest RMSE MSE and MAE for both model fitting and model validating.

This research presents an Analysis of Voltage Sags on the Installation of Distributed Generation in the Distribution System. The computer program PSCAD/EMTDC (Power Systems Computer Aided Design / Electromagnetic Transient in DC system) version 4.2 is applied to provide electrical parameters for the modeling and simulation and to analyze the fault occurred which resulted in voltage sag. Test results from PSCAD/EMTDC show the values of voltage sag when 5 types of fault are occurred (Single Line to Ground Fault Double Line to Ground Fault Three Phase to Ground Fault Line to Line Fault and Three Phase Fault). For all cases the value of root mean square voltage before fault is 100% or 1.0 pu. It can be seen that for both radial line and closed circuit when DG are installed in the system the value of phase to ground RMS residual voltage and phase to phase RMS residual voltage at the bus of Bang-pa-in 2 substation are more than the values in case of the system without DG.

The objective of this research was presented a decision support making process for efficiency improvement of drinking water processing using retrofit technique for machine and equipment rehabilitate. This methodology was applied Analytic Hierarchy Process (AHP) for selecting an appropriate maintenance sub-contractor. To complete the research existing water purifying machine and tools were inspected to assess its capacity. Future capacity of the purifying machine was also identified. Consequently machine and tools such as water tank and water filter were inspected for retrofitting for the example water tank water filter water quality control and bottle packing. Finally the analytic hierarchy process was utilized to select the most appropriate maintenance sub-contractor. In this process both qualitative and quantitative processes were analysed. The result of this research has been found that this multicriteria decision making process could be used to support the decision making investment process of water purification retrofit unit at Faculty of Engineering Rajamangala University of Technology Phra Nakorn efficiently. Furthermore it could be reduced bias from decision makers while the decision was accepted by all stakeholders.

This thesis presents a method of compare the reducing high voltage source more than necessary to the pilot study two plants in case of load near power station the same distance but different. There are 2 methods first method reducing the voltage by adjusting tap transformer. Other method installed by voltage equipment. Regulator in a factory used 2 methods for measured the value of voltage before&after and continued to reduce the voltage until minimum loading that this factory can normal operate. From two trials we found that reducing the voltage by installation voltage regulator/voltage equipment can save more energy cost 10.23% than adjusting tap transformer that can save only 4.66%. And analysis of Specific Energy Consumption (SEC) by reducing the voltage level of the industry. Energy consumption kWh per 1 output (plastic bottles) Then lower from 0.119 kWh per 1 bottle remaining 0.089 kWh per 1 bottle This is in line with the energy analysis that main control electric power.