Browsing by Subject "Tracking"
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ItemA comparative study of kindergarten students' levels of English achievement by way of tracking and detracking at ChockChai Hathairaj School in Bangkok, ThailandThe purpose of this study was to compare Kindergarten students’ levels of English achievement by way of two different grouping arrangements known as tracking and detracking at Chokchai Hathairaj School in, Bangkok, Thailand. This study was to determine if any statistically significant difference existed between those instructed in accordance with tracking and those instructed in accordance with detracking in terms of their respected levels of English achievement. This study was conducted over a period of nine weeks from July 2020 to August 2020. A total of 60 Kindergarten students took part in this study. In this study, 30 students were grouped according to ability as determined by a pre-test and in accordance with tracking and 30 students were grouped randomly regardless of ability in accordance with detracking. This study used a pre-test and a post-test to identify students’ levels of English achievement. The test scores were analyzed by of statistical analysis including mean and standard deviation and compared by way of paired samples and independent samples t-tests The findings showed there was a significant difference between pre-test and post-tests by ways of both tracking and detracking at the .05 level. The findings also showed no significant difference existed in gain difference between pre-tests and post-tests by way of tracking and detracking at the .05 level.
ItemTracking of High-speed, Non-smooth and Microscale-amplitude Wave Trajectories( 2016) Jiradech KongthonIn this article, an inversion-based control approach is proposed and presented for tracking desired trajectories with high-speed (100Hz), non-smooth (triangle and sawtooth waves), and microscale-amplitude (10 micron) wave forms. The interesting challenge is that the tracking involves the trajectories that possess a high frequency, a microscale amplitude, sharp turnarounds at the corners. Two different types of wave trajectories, which are triangle and sawtooth waves, are investigated. The model, or the transfer function of a piezoactuator is obtained experimentally from the frequency response by using a dynamic signal analyzer. Under the inversion-based control scheme and the model obtained, the tracking is simulated in MATLAB. The main contributions of this work are to show that (1) the model and the controller achieve a good tracking performance measured by the root mean square error (RMSE) and the maximum error (Emax), (2) the maximum error occurs at the sharp corner of the trajectories, (3) tracking the sawtooth wave yields larger RMSE and Emax values,compared to tracking the triangle wave, and (4) in terms of robustness to modeling error or unmodeled dynamics, Emax is still less than 10% of the peak to peak amplitude of 20 micron if the increases in the natural frequency and the damping ratio are less than 5% for the triangle trajectory and Emax is still less than 10% of the peak to peak amplitude of 20 micron if the increases in the natural frequency and the damping ratio are less than 3.2 % for the sawtooth trajectory.