This paper presents the simulation and experimental result of class-E power amplifier. It is often used in designing a high frequency ac power source because its ability to perform the conversion efficiently even at high frequencies with significant reduction of switching losses. This paper aims to compare the transmission performance of electrical power between the air core transformer and iron core transformer which the identical input voltage of 50 VAC. Both transformers are designed to step voltage up (step up transformer) ratio of 1:4.5. The Arduino microcontroller Arduino was used to generate a pulse width modulation (PWM) with operating frequency of 3.74 kHz. IC gate drive TC4422 was used to drive the IRF510 MOSFET. Based on the simulation and experimental results the power loss in air core transformer is 75 percent while power loss in iron core transformer is 0.2 percent. The maximum distance that can transmit electric power of air core transformer is 9.3 centimeters.

The objectives of this study were to calculate the probability of type I error power of a test and to compare the performance of three test statistics: Z Student’s t and Welch’s t. Including the recommending the appropriate test statistic. Classification of the population according to five distribution. The ratios of mean group 1 per group 2 were three levels. The ratios of variance group 1 per group 2 were three levels. The sample sizes of two populations were nine sizes. The significance levels that to study were 0.01 and 0.05. The data were simulated by using SAS programming with 1000 replicates. Results of the research were Z test statistic could control the probability of type I error and had higher power of a test than other test statistics but this test is necessary to know the variances of the two groups. Therefore it was appropriate to apply the other test statistics i.e. Student’s t or Welch’s t. If the variances of the two groups were equal Student’s t was a more appropriate test statistic than Welch’s t. But if the variances of the two groups were not equal Welch’s t was a more appropriate. When both sample sizes were large and the population variances were equal we could use any tests since there is no difference in the performance.

โครงการวิจัยนี้ มีวัตถุประสงค์เพื่อศึกษาและเปรียบเทียบประสิทธิภาพการตัดเฉือนของโปรแกรมงานกัดด้วยเครื่องกัดอัตโนมัติสำหรับการผลิตชิ้นส่วนในอุตสาหกรรม โดยการเปรียบเทียบทิศทางการกัดงานที่ผ่านการกัดโดยใช้ G41 และ G42 เอ็นมิลล์่ขนาด 12 มม. 4 คมตัดชิ้นงานที่ใช้ในการทดสอบเป็นเหล็ก S45C โดยกัดชิ้นงานที่ระยะทาง 3000 มม. ใช้เครื่องกัดจำนวน 3 เครื่อง การวิจัยนี้ทดลองภายใต้เงื่อนไขเดียวกัน ผลการวิจัยและทดสอบข้อมูลทางสถิติโดยการเปรียบเทียบโปรแกรมการกัดงาน โดยใช้ G41 และ G42 ปรากฎว่าชิ้นงานที่ผ่านการกัดงานโดยใช้ G41 และ G42 มีความแตกต่างกันอย่างมีนัยสำคัญ ที่ระดับนัยสำคัญ 0.05 โดยชิ้นงานที่ผ่านการกัดงานโดยใช้ G41 การสึกหรอที่ดอกเอ็นมิลล์จะเกิดขึ้นน้อย แต่ผิวที่ได้จะมีความหยาบส่วนชิ้นงานที่ผ่านการกัดงานโดยใช้ G42 การสึกหรอที่ดอกเอ็นมิลล์จะเกิดขึ้นมาก แต่ผิวที่ได้จะมีความละเอียดมากกว่า

This paper presented the effectiveness of clustering data – the results from when the Fuzzy Kernel Compactness and Separation (FKCS) were proposed to compare with the performance of the Kernel Noise Clustering (KNC). The FKCS and KNC had largely been developed through basic steps of the Fuzzy Compactness and Separation (FCS) and Noise Clustering (NC) respectively. Ring data sets were used to test the effectiveness of clustering data between the FKCS and the KNC. In doing so the kernel function – the kernel gaussian function and the kernel polynomial function were used as testors. Along those processes noise data was added in order to test noise-resistant capacity of Fuzzy Kernel C-Mean (FKCM) FKCS and KNC. The results of the tests provided quite knowledgable understanding that when trying out with the ring datasets the FKCS with kernel gaussian function and kernel polynomial function could perform effectively clustering data. Moreover the KNC was even more robust and could work out better with noise data than the FKCM or the FKCS could.

Currently the internet services with 3G technology by mobile phone operators in Thailand are different in the performance. The mobile phone operators have already launched 3G technology with 2G frequency ranges which are limited in the efficiency. This paper aims to compare the efficiency of the internet service with 3G technology by three mobile phone operators (AIS DTAC and Truemove H) in Thailand. There are three type of testing as follows: Ping to both domestic and international website Bandwidth speed test and FTP Test (upload and download) are used to evaluate the performance of these mobile phone operators. There were five places in Bangkok where are the top of the network congestion list for such testing the three mobile phone operators. The result showed that AIS gives the best performance in the ping test. Truemove H introduces the best performance in both FTP and Bandwidth speed test. The DTAC performances are moderated level for every tests.