จำนวน Repository ( 3447 )
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.
การจำลองกังหันลมเชื่อมต่อระบบกริดไฟฟ้า 1 เฟส
This research project presents about wind turbine simulation for connected single phase grid system using hysteresis current control technique to generate PWM signals for controlling a single-phase voltage source inverter. The simulation system presented here uses the program. MATLAB/Simulink in the simulation of the wind turbine connected to the shaft of a three-phase permanent magnet generator is produced by alternating current through the full bridge rectifier circuit. Then the power supply is applied to the single-phase inverter circuit which is connected to the single-phase autotransformer to power transfer to the single-phase grid system. The simulation results confirm the validity of the proposed system with satisfaction under various conditions.
การสร้างและหาประสิทธิภาพชุดสาธิตการจำลองกรณีศึกษาของระบบไฟฟ้าในระบบปรับอากาศ
This project is intended as a teaching medium air conditioning system and simulation of air conditioning system problems. Some of them have been modified to suit their teaching needs. Arduino microcontrollers are used to control the system. By starting the study of the air conditioning system thoroughly. The microcontroller is written to control the operation of devices like the air conditioning system when the system malfunction. It will be used to analyze the problems of air conditioning. The experimental set will display the voltage and current. The connection points of the air conditioning problem analysis. When the symptoms are bad. The analyst can solve the problem by connecting or pressing the button of the device. The results of the project. The test will measure the difference of the air conditioning unit. And read the amount of current and volume in the system. To diagnose abnormalities and choose a solution to the problem from the kit system that can be displayed to solve the problem that the analyst was correct or not with the LED status light. Based on the performance test a demonstration kit for the demonstration of efficiency of the air conditioning system was provided to 10 experienced air conditioning technicians. 80s of issues. The reliability of the demonstration set and the efficiency of the simulator case study of the electrical system in air conditioning systems is acceptable
เทคนิคการแบ่งส่วนของข้อมูลภาพเอสเออาร์ด้วยวิธีวอร์เตอร์เฉดและปรับเรียบฮีสโตแกรม
Since the details in quasi-homogeneous region will be degraded from a conventional global image enhancement methods such as histogram equalization. This degradation causes from the saturation of the gray levels in equalization process. Then the local histogram equalization for each quasi-homogeneous region will be used in order to improve the details in the regions. To obtain the quasi-homogeneous regions the image can be segmented by using a watershed transform. The watershed transform is based on mathematical morphology; therefore the segmented regions can be effectively separated meaningful. Two adjacent regions in images which almost similar in gray levels can be separted by the watershed transform. In the color image enhancement three spectral bands are enhanced independently. Then all the three bands are assigned to each processed image in order to produce a color composite image. By the proposed algorithm the result images show the better perception on image details. Therefore the high efficiency of image classification can be obtained by using this color image.
การศึกษาสภาวะที่เหมาะสมสำหรับการหล่อขึ้นรูปตัวเรือนเครื่องประดับโลหะเงินเจือสีชมพู 54%
The results of the experiments were found that the temperature of the castings was higher than that of the silver alloys. The workpiece temperature is 500C the workpiece is good 26%. The workpiece is 74%. The temperature is 550C. The workpiece is 26%. The workpiece is 74%. The temperature is 600C. The workpiece is 40%. The workpiece is 60%. The workpiece is a fin. There are many factors that cause fins on the workpiece. Use of low-strength mortar In addition the use of excessive compression or heat transfer resulting in the expansion and shrinkage is not equal. This causes the cracking of the metal water to expand at a temperature of 650 ° C. The fine specimen 56% of the workpiece loses 44%. This temperature results in the smallest workpiece caused by the uneven surface. Cause of the cooling rate in each part of the casting is not equal. And at 700 degrees Celsius it is best to cast silver ornaments with pink color because the results show that the work is minimal. There are 70% good work piece 30%