Browsing by Author "Chen, Chih-Hao"

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Elucidating the Physical Property of the InGaN Nanorod Light-Emitting Diode: Large Tunneling Effect
(2011-07-01)
Lee, Ya-Ju
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Lee, Chia-Jung
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Chen, Chih-Hao
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Lu, Tien-Chang
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Kuo, Hao-Chung
The current-voltage (I-V) characteristics of the InGaN nanorod light-emitting diode (LED) are evaluated using nanoprobes installed on a field-emission scanning electron microscope. The saturated current of the InGaN nanorod LED (I(O) = 2 x 10(-9) A) is found to be orders of magnitude higher than those obtained by downscaling a conventional InGaN LED to a chip size of 300 x 300 mu m(2) (I(O1) = 1 x 10(-25) A; I(O2) = 1 x 10(-14) A). This observation is explained by the fact that the nanorod LED is associated with enhanced tunneling of injected carriers and, therefore, reduction of the defect-assisted leakage current and the diffusion-recombination process that normally occurs in InGaN LEDs.
EOG-Based Eye Movement Classification and Application on HCI Baseball Game
(2019-01-01)
Lin, Chin-Teng
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King, Juang-Tai
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Bharadwaj, Priyanka
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Chen, Chih-Hao
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Gupta, Akshansh
Electrooculography (EOG) is considered as the most stable physiological signal in the development of human-computer interface (HCI) for detecting eye-movement variations. EOG signal classification has gained more traction in recent years to overcome physical inconvenience in paralyzed patients. In this paper, a robust classification technique, such as eight directional movements is investigated by introducing a concept of buffer along with a variation of the slope to avoid misclassification effects in EOG signals. Blinking detection becomes complicated when the magnitude of the signals are considered. Hence, a correction technique is introduced to avoid misclassification for oblique eye movements. Meanwhile, a case study has been considered to apply these correction techniques to HCI baseball game to learn eye-movements.
Gaming Controlling via Brain-Computer Interface Using Multiple Physiological Signals
(2014)
Chen, Shi-An
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Chen, Chih-Hao
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Lin, Theng-Wei
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Ko, Li-Wei
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Lin, Chin-Teng
using physiological signals to control braincomputer interface (BCI) becomes more popular. Among many kinds of physiological signals, Electrooculography (EOG) signal is more stable which can be used to control BCI systems based on eye movement detection and signal processing methods. Also, the use of electroencephalographic (EEG) signals has become the most common approach for a BCI because of their usability and strong reliability. In this paper, we described a signal processing method, which uses a wireless EEG-based BCI system designed to be worn near forehead that can detect both EEG and EOG signals, for detecting eye movements to have 9 direction controls (via EOG) and one action of execution (via EEG). This system included a wireless EEG signal acquisition device, a mechanism that can be worn stably, and an application program (APP) with signal processing algorithms. This algorithm and its classification procedure provided an effective method for identifying eye movements and attention. Finally, we designed a baseball game to test the BCI system. The results demonstrated that player can control the game well with high accuracy.
Influence of liquid hydrophobicity and nozzle passage curvature on microfluidic dynamics in a drop ejection process
(2010-01-01)
Lai, Jr-Ming
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Huang, Chang-Yan
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Chen, Chih-Hao
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Kung Linliu
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Lin, Jenn-Der
Employing methods of computational fluid dynamics, we investigated the physical phenomena and fluid dynamics of a microfluid during ejection of a droplet with a designed system of a nozzle plate connected to a flat-plate piezoelectric material. A comparison between experimental measurements and numerical simulations was devised to validate the theoretical model. The volume-of-fluid piecewise linear-interface construction (VOF-PLIC) interface-capturing method was adapted to represent the fluid domain and to track the evolution of its free boundaries whereas the continuous surface force (CSF) mode was chosen to model the interfacial physics. The results show that the curvature of the flow channel affects the velocity, period before disintegration, volume of the droplet and number of satellite drops. Increasing the diameter of the orifice increases the volume and decreases the velocity of the droplet. Increasing the amplitude or frequency of the nozzle plate raises the input energy, so increasing the velocity, decreasing the volume and hastening the disintegration of the droplet, but an increased amplitude or frequency increases the number of satellite drops. At the hydrophobic boundary, the velocity increases, the droplet volume decreases and the period before disintegration is abbreviated because of the decreased adhesive force between the fluid and the boundary surface.
Selective C(8)-H Activation of Imidazopyridines Mediated by Cooperative Nickel-Aluminum Catalysis
(2016-09-01)
Liu, Cheng-Yuan
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Chen, Ying-Ho
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Chen, Chih-Hao
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Yu, Ming-Shiuan
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Tsai, Fu-Yu
A catalytic paradigm is described featuring a synergistic interaction between nickel, aluminum and different ligands to impart a rather remote C-H alkenylation of imidazo[1,5-a] pyridines at the C-8 position without the necessity of installing a directing group. The scope of the direct C-H activation reactions of various 5-aryl- and 3-arylimidazopyridines is established using different sterically hindered alkynes.