จำนวน Repository ( 10 )
ตัวแบบผสมเชิงเส้นสาหรับข้อมูลอนุกรมเวลาเชิงพื้นที่ที่มีฤดูกาลรวมอยู่ด้วยประยุกต์ใช้กับผลผลิตยางพาราในจังหวัดภาคใต้ของประเทศไทย
The objectives of this research are to propose a linear mixed model (LMM) for spatial time series with a seasonal component to apply the proposed model to monthly rubber yields in southern provinces of Thailand to forecast rubber yields in southern provinces of Thailand and to compare the performance of the proposed model to the Holt-Winters Additive Exponential smoothing model (Holt-Winters ES) and the seasonal autoregressive integrated moving average model (SARIMA). The proposed model is a linear mixed model (LMM) with spatial effects following a conditional autoregressive model (CAR model). Seasonal dummy variables and Fourier terms are two methods used to account for the seasonal effects. A Bayesian method is used for parameter estimation. The estimated monthly yields are used to forecast the monthly rubber yields. The dependent variables are the monthly rubber yields in each province. The effects considered are spatial effects heterogeneity effects and seasonal effects. The data are secondary data at a provincial level. The results show that the effects influencing on the amount of rubber yields are spatial heterogeneity and seasonal effects. The proposed model with sesonal dummy variables is the most appropriate model copared to the LMM with Fourier sesonal effects Holt-Withers ES and SARIMA. The mean absolute errors (MAE) are smallest in both model fitting and model validating parts. The proposed model with sesaonal dummy variables should be the first consideration for forecasting spatial time series with a seasonal component.
ตัวแบบเบย์สำหรับข้อมูลอนุกรมเวลาเชิงพื้นที่ ประยุกต์ใช้กับผลผลิตยางพารา ในจังหวัดภาคใต้ของประเทศไทย
The objectives of this research are to propose a Bayesian model for spatial time series analysis to apply the proposed model to forecast a monthly rubber yield in Southern provinces of Thailand and to compare the performance of the proposed model with the classical Holt-Winters Additive Exponential smoothing. The proposed model is a linear mixed model (LMM) with spatial effects which follow a conditional autoregressive model (CAR). Dummy variables are used for seasonal effects. A Bayesian method is used for parameter estimation. The estimated monthly yields are used for the monthly rubber yield forecasting. The dependent variables are the rubber yield in each month of each province. The data are secondary data at a provincial level. The factors considered are spatial effects heterogeneity effects and seasonal effects. The results show that the factors influencing on the amount of rubber yields are spatial heterogeneity and seasonal effects. The proposed model is proper and forecast accurately. Using the mean absolute error (MAE) the proposed model has a better performance compared to the classical Holt-Winters Additive Exponential smoothing in both model fitting and model validating. The proposed model should be the first consideration for spatial time series forecasting.
การวิเคราะห์สาเหตุของการผลิตสินค้าบกพร่องและเสียด้วยตัวแบบการถดถอยโลจิสติกส์แบบเบย์: กรณีศึกษาโรงงานผลิตชิ้นส่วนรถยนต์
This research proposes a Bayesian logistic regression model which is applied to the data from autoparts manufacturing machines. Factors related to defective and bad products are investigated. The proposed model is compared with the logistic regression using maximum likelihood method for parameter estimation. The data were collected from 132 machines in an autoparts manufacturing factory. The research found that useful life machine type 6 worker group 3 and 4 working step 1 and 2 influence to the risk of producing defective and bad products. When the useful life is increased by 1 month the risk of producing defective and bad products will be increased by 2.2%. The risk that the machine type 6 will produce defective and bad products is 4.078 times greater than the risk that the machine type will do. The risk that the worker group 3 will produce defective and bad products is 61.7% less than the risk that the worker group 12 will do. The risk that the worker group 4 will produce defective and bad products is 61.5% less than the risk that the worker group 12 will do. The risk that the working step 1 will produce defective and bad products is 2.831 times greater than the risk that the working step 4 will do. The risk that the working step 2 will produce defective and bad products is 13.8 % greater than the risk that the working step 4 will do. The parameter estimates from the Bayesian logistic regression are very close to the ones from the logistic regression using maximum likelihood method for parameter estimation
Creating and Finding Efficiency Validation of Computer Assisted Instruction Focused on the Practiced to Torsion Test
The purposes of the research were to create and find efficiency validation of computer assisted instruction focused on the practice to Torsion Test for the standard 90/90 and analyze the students learning achievement after using computer assisted instruction. The samples were the 20 first year Bachelor of Engineering Program in Industrial Engineering Rajamangala University of Technology Phra Nakhon. The researcher experimented by using pretest and then using the computer assisted instruction focus on the practice to Torsion Test in learning next the students did the posttest. After that the researcher calculated to find the computer assisted instruction efficiency and analyzed the students learning achievement after studying. The result revealed that the computer assisted instruction efficiency was efficient for standard 90/90. And after studying by using computer assisted instruction the students learning achievement increased significantly at 0.05.
Creating and Finding Efficiency Validation of Computer Assisted Instruction Focused on the Practiced to Hardness Test
The purposes of the research were to create and find efficiency validation of Computer Assisted Instruction Focused on the Practiced to Hardness Test for the standard 90/90 and analyze the students’ learning achievement after using computer assisted instruction. The samples were the 20 first year Bachelor of Engineering program in lndustrial Engineering Rajamangala University of Technology Phra Nakhon North Bangkok Campus.