• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.5
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• pp.146-150
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• 2004

The effects on non-thermal plasma generation by duty Ratio and frequency of pulse voltage were investigated experimentally. For these, a new type of non-thermal plasma generator with mesh electrode was manufactured and it was possible to generate the surface and silent discharge simultaneously by new type of non-thermal plasma generator. Duty ratio and frequency were selected as main parameters to control the movement of electron which is mainly related to the non-thermal plasma generation. The characteristics of non-thermal plasma generation were investigated indirectly by measuring the I-V curve and quantity of ozone generation. The most effective condition of duty ratio and frequency to generate the non-thermal plasma was identified by experiments with manufactured non-thermal plasma generator.

• PNF and Movement
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• v.17 no.2
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• pp.321-327
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• 2019

Purpose: This study aimed to investigate the effects of the crocodile breathing exercise on the muscle activity of the erector spinae muscle in patients with low back pain. Methods: The study subjects included 36 patients with low back pain. The patients were divided equally into the experimental group (EG) and the control group (CG). The EG performed the crocodile breathing exercise, and the CG performed a chest expansion breathing exercise. The intervention was conducted for 10 minutes each day for a total of eight weeks. Measurements of muscle activity were conducted using an MP150 system. An electrode was attached 2 cm to the side of the spinous process at the L4-L5 level. The muscle activity value used was %MVIC, and the statistical significance was 0.05. The paired t-test was the statistical method used to determine the pre- and post-average value of each breathing exercise, while the independent t-test was used to assess the delta value of muscle activity in the pre-post test. Results: Inspiration muscle activity showed a significant increase in both the EG and the CG, while expiration muscle activity decreased significantly in both groups. The delta value of muscle activity showed a significant difference in inspiration (p<0.05), but for expiration, there was no significant difference in muscle activity (p>0.05). Conclusion: This study suggests that crocodile breathing is a good method for improving muscle activity in patients with low back pain.

• Membrane Journal
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• v.30 no.1
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• pp.38-45
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• 2020

Although Lithium metal battery (LMB) has a very large theoretical capacity, it has a critical problem such as formation of dendrite which causes short circuit and short cycle life of the LMB. In this study, PDMS/GO composite with evenly dispersed graphene oxide (GO) nanosheets in poly (dimethylsiloxane) (PDMS) was synthesized and coated into a thin film, resulting in the effect that can physically suppress the formation of dendrite. However, PDMS has low ion conductivity, so that we attained improved ion conductivity of PDMS/GO thin film by etching technic using 5wt% hydrofluoric acid (HF), to facilitate the movement of lithium (Li) ions by forming the channel of Li ions. The morphology of the PDMS/GO thin film was observed to confirm using SEM. When the PDMS/GO thin film was utilized to lithium metal battery system, the columbic efficiency was maintained at 87.4% on average until the 100^th cycles. In addition, voltage profiles indicated reduced overpotential in comparison to the electrode without thin film.

• The Journal of Korean Institute of Information Technology
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• v.15 no.12
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• pp.157-164
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• 2017

Mobile ECG signal measurement is a technique to measure small signals of several mV, and many studies have been conducted to remove noise including wandering scheme. Removal of the equipotential line noise caused by shaking or movement of the electrode cable is one of the core research contents for the electrocardiogram measurement. In this study, we proposed a modified step-size of combined NLMS(normalized least squares) and DLMS(delayed least squares) adaptive filter to eliminate baseline noise from ECG signals. The proposed method mainly adjusts initial filter step-size to reduce distortion of original ECG signals characteristic after eliminating baseline noise. The modified filter step-size is scaled by filter order size and distortion minimization factor. This method is suitable for portable ECG device with a small processor and less power consumption. This technique also decreases computation time which is essential for real-time filtering. The proposed filter also increase the signal to noise ratio (SNR) compared to conventional NLMS filter.