จำนวน Repository ( 720 )
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.
The design and construction of remote control lawn mower by radio wave
Thesis is the development of radio-controlled lawn mower which can move and cut the grass in the desired environment and dangerous to human. The objective is to develop a radio-controlled lawn mower. The results showed that the rate of fuel consumption of controlled lawn mower in to cutting grass. The height of the grass at 6 8 and 10 cm. It has the average fuel consumption is 113 117 and 123 ml. The average time in the mowing is 6.6 8.01 and 9.69 minutes
An induction furnace with half bridge resonant inverter for brass
This research presents the design and construction of molten brass to form the basis of induction heating. It is heated by the half-bridge voltage source in series resonant load by transferring the heat energy through the graphite crucible for 300 grams melting of the brass in 10 minutes. The system is controlled to operate at a higher frequency than the resonance frequency mode with the input three-phase AC voltage 380 V 50 Hz through a rectifier into a DC voltage to be supplied to the inverter supply voltage half-bridge about 35 kHz switching frequency at the rated power 4.5 kW
A development of python script for analysis and design reinforced concrete beam
This research studies the development of Python Script which is the open source code used for the analysis design and draws the detailing of reinforced concrete beam elements. The SGV script was used for detailing the output of beam section. The results of the research shown the development of Python Script can be used for the analysis design and draw the reinforced concrete bean sections. The output of shear force diagram and bending moment diagram can be applied for design beam sections by the strength design method and draw the detailing of beam sections
การเลือกฟังก์ชันการแจกแจงความน่าจะเป็นสะสมสำหรับแนวโน้มเพื่อสร้างตัวแบบสำหรับวิเคราะห์ข้อมูลอนุกรมเวลาหลายๆตัวพร้อมกันที่มีค่า อัตตสหสัมพันธ์แนวโน้ม และค่าผิดปกติ ด้วยวิธีของเบย์: กรณีศึกษาราคาหุ้นที่มีความผันผวนของตลาดหลักทรัพย์แห่งประเทศไทย
The objective of this research is to select a proper cumulative function for trend in an analysis of simultaneous multiple time series data with autocorrelation trend and outliers using a Bayesian method. The proposed model is applied to fluctuate stock price data in the stock exchange of Thailand. The data consist of the closing prices of 5 stocks. The algorithms are written in OpenBUGS and the performance of the model is evaluated via a simulation study in R. The cumulative distribution functions considered here are a Weibull cumulative distribution function and an exponential cumulative distribution. They are compared using RMSE MAPE and MAE as criteria. The research found that an exponential cumulative function for trends gives smaller values of the three criteria in both model fitting and model validation for the4 stocks EA NWR and KTB. However a Weibull cumulative distribution function gives smaller values of three criteria for the PTT in both model fitting and model validation.