จำนวน Repository ( 143 )
การเลือกแบบจำลองที่เหมาะสม สำหรับพยากรณ์ข้อมูลอนุกรมเวลาเชิงพื้นที่ ผลผลิตข้าวและยางพารา ของประเทศไทย
The objectives of this research were to propose a model with some functions including CAR spatial effects and to select a proper model for predicting rince and rubber yields in southern provices of Thailand. A linear mixed model (LMM) with spatial effects and dummy varables and Fourier seasonal effects was proposed. Bayesian estimation was used and the estimated rice and rubber yields were used for prediction. The dependent variables were rice and rubber yields in southern provinces of Thailand. Factors considered were rain temperature soil fertilizer soil organic matter trend and also sesonal effects. The results show that rain temperature soil fertilizer soil organic matter trend and sesonal effects influence on rice and rubber yields. The proposed model with Fourier seasonal term is the most appropriate comparing to the model with dummy variable for season effects and the Holt-Winters model. Therefore the proposed model with Fourier sesaonal term should be the first consideration for prediction.
การพยากรณ์ภัยแล้งในประเทศไทย โดยใช้การวิเคราะห์เชิงพื้นที่ด้วยแบบจำลองผสมเชิงเส้นวางนัยทั่วไปแบบเบย์
The objectives of this research were to propose a spatial analysis using Bayesian generalized linear mixed model for predicting drought in Thailand. The spatial effect was assumed to be a conditional autoregressive model (CAR model). The dependent variables was a drought or non-drought occurrence which was assumed to have a Bernolli distribution with logistic link function. Factors considered were rain temperature number of rainy days number of large reservoirs and number of medium reservoirs. The results show that the rain temperature number of rainy days number of large reservoirs and number of medium reservoirs influence on the drought occurrence. This study is useful for planning making decision preventing and remedying the drought problem.
การเลือกฟังก์ชันฤดูกาลที่เหมาะสม ในตัวแบบอนุกรมเวลาแบบเบย์ สาหรับวิเคราะห์ราคาและผลผลิตยางพารา ในประเทศไทย
The objectives of this research were to create a model for time sereries data prices and yields of natural rubber to be more accurate prediction and to compare the proposed model with the classical time series models such as the Holt-Winters Additive Exponential smoothing model (Holt-Winters ES) and the seasonal autoregressive integrated moving average model (SARIMA). The proposed model was a linear mixed model (LMM) consisting with trend autoregression outliers and sesonal terms. Dummy varialbles and Fourier seasonal effects were studied. Bayesian estimation was used and the estimated prices and yields were used for prediction. The results show that the proposed model with a Fouries seasonal effect is the most appropriated comparing with the dummy seasonal effect the Holt-Winters ES and the SARIMA having the least mean absolute values (MAE) both fiting and validating parts. The proposed model with sesaonal dummy variables should be the first consideration for forecasting spatial time series with a seasonal component.
รูปแบบสมรรถนะเพื่อการเรียนรู้เทคโนโลยีดิจิทัลของผู้สูงอายุในเขตกรุงเทพมหานคร
The purposes of this study were to investigate the component and competency model for learning in digital technology of the elderly in Bangkok. The sample of this study consisted of 385 elderly people in Bangkok. The instruments used in research were questionnaire and interview. The statistics used for data analysis were percentage arithmetic mean standard deviation and Exploratory Factor Analysis (EFA). The findings of the data analysis indicate that there were 6 components with 36 variables of competency for learning in digital technology of the elderly in Bangkok which can describe the combined variance at 64.305 percent. All components were as follow: 1 component of the knowledge competency to identify the learning course 3 components of the skill competency to identify the learning objective learning management and promote learning. Finally 2 other components of the personal competency to identify the background of learner and physical and mental fitness.
ตัวแบบผสมเชิงเส้นที่มีความสัมพันธ์เชิงพื้นที่รวมอยู่ด้วย สำหรับ วิเคราะห์ผลผลิตข้าว ในแต่ละจังหวัดของประเทศไทย
The objectives of this research are to propose a linear mixed model (LMM) with spatial correlation for an analysis of rice yields in Thailand to estimate the rice yield in each month of all provinces in Thailand to investigate factors influencing on the rice yields and to construct the maps of rice yields. A linear mixed model (LMM) in which the spatial effects follow the conditional autoregressive model (CAR) is used. The estimated rice yields are used to construct the rice yield maps. The dependent variables are the rice yield in each month of each province. The data are secondary data at a provincial level. The factors considered are rainfall averaged temperatures and regions. The results show that the factors influencing on the rice yields are rainfall averaged temperature and region. The amount of regional effects ordering from largest to smallest values are northestern region southern region western region central region eastern region and northern region respectively. The top ten provinces and months with high yields ranking from largest to smallest values are Ubon Ratchathani in November (1328000 ton) Surin in Novermber (1070000 ton) Si Sa Ket in Novermber (1023000 ton) Buri Ram in November (939400 ton) Nakhon Ratchasima in November (907500 ton) Roi Et in Novermber (852800 ton) Chiang Rai in Novermber (769800 ton) Khon Kaen in Novermber (692800 ton) Maha Sarakham in Novermber (676200 ton) Udon Thani in Novermber (620600 ton) respectively. The rice yeilds maps are easy for readers to identify which areas have high or low yields. They are a useful tool for planning decision making and implementing plans to help rice famers to increase their rice production.