จำนวน Repository ( 22 )
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.
การพยากรณ์ราคาพริกไทยดำ
The objective of this study was to construct the black pepper prices forecasting model by 4 statistical methods: Box-Jenkins method Holt’s exponential smoothing method Brown’s exponential smoothing method and damped trend exponential smoothing method. Time series of monthly black pepper prices which were gathered from the website of the Office of Agricultural Economics during January 2005 to December 2018 of 168 observations were divided into 2 datasets. The first dataset had 156 observations from January 2005 to December 2017 for constructing the forecasting models. The second dataset had 12 observations from January to December 2018 for comparing the accuracy of the forecasts via the criteria of the lowest mean absolute percentage error (MAPE) and root mean squared error (RMSE). Research findings indicated that for all forecasting methods that had been studied the most accurate method was damped trend exponential smoothing method (MAPE = 6.5773 RMSE = 10.3775)
การสร้างเงื่อนไขเริ่มต้นในการพยากรณ์อากาศ
Weather forecasts are very necessary to predict the future weather conditions. The important thing in forecasting is the model and variables. The model used in the forecasting must be accurate and effective. In addition the variables used in forecasting must be comprehensive and appropriate to be able to represent the forecast. The initial conditions for forecasting must be appropriate and reliable. There are many methods to generate the initial conditions in forecasting. To generate the initial conditions for winter monsoon prediction with Kalman Filtering method which is a method used to predict the status of various systems and able to create values of variables used in forecasting to have a variety of similarities can be used as a starting variable in forecasting very well. In this research the winter monsoon prediction by the Shallow Water Model and validating the initial conditions by Root Mean Square Error (RMSE). The result of weather prediction in the winter monsoon can be used the Kalman Filtering method for generate the initial conditions.
การพยากรณ์ราคาข้าวโพดเลี้ยงสัตว์ของประเทศไทย
The purpose of this research was to construct the appropriate forecasting model for the prices of field corn in Thailand using four time series analysis methods including Box-Jenkins method Holt’s exponential smoothing method damped trend exponential smoothing method and combined forecasting method. Time series data from the website of the Office of Agricultural Economics with total 227 months during January 1997 to November 2015 are used and divided into two series. The first 216 months from January 1997 until December 2014 used to build the forecasting models and the last 11 months from January until November 2015 used to compare the forecasting methods accuracies via the criteria of the lowest mean absolute percentage error and root mean squared error. Research finding indicated that combined forecasting model was the most accurate.
การพยากรณ์กำลังรับแรงกระแทกของปอซโซลานคอนกรีตด้วยแบบจาลองฟัซซีลอจิก
This objective research to study the possibility of used properties pozzolan material for concrete cement the ternary blend by fly ash metakaolin and silica powder by replacement cement partially on the strength for Flexural and impact by replace Portland cement. Consideration of concrete by varying the ratio there are three values are (w/d) of 0.38 0.55 and 0.8 follow on standards ACI 211.1-91 and variable amounts of replacement cement some. The ternary blend of the fly ash metakaolin and silica powder of percentage 0 15 20 and 25 and by weight of cement. and the control specimens (w/b) without contain fly ash kaolin and silica powder the slump test in the range of 3-5 cm and the use super plasticizer to control the slump test of concrete. By casting specimens of cylindrical diameter 10x20 cm cube 10x10x10 cm and the beam size 10x10x35 cm after curing 28 days and test compressive tensile and flexural strength of concrete all specimens The results showed that The increase will help improve the quality of the concrete physical properties 35 percent up on the cement with clay 15 percent will have the strength to most of the compression is reduced. The increased of compressive and Tension strength as the percentage decrease when replacing cement with fly ash 35 percent up on replacing cement with clay to pull the maximum percentage of 10 bending when replacing cement with clay at a ratio of 10 percent is paid bending. The maximum value of fly ash the flexural increased replace cement in the ratio of 50 per cent are increased the concrete with the most and the last place of cement. As a result of the porosity of the concrete with lower amounts of tightness concrete has increased. Fuzzy logic model is presented for predicting the strength for Flexural and impact by replace Portland cement. The result of the study from experimental case the graph of membership function are present (low medium and high). The results showed that the model Fuzzy Logic. Can be used fuzzy logics to predict as well