• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.7
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• pp.140-148
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• 2017

The purpose of this study was to examine the effects of acute aerobic exercise at different intensities on the blood pressure, blood lipids and fibrinolytic markers in pre-hypertension college-aged males. Six subjects performed an acute running exercise at three different intensities(low intensity(LI): 50-60% heart rate reserve(HRR), moderate intensity(MI): 60-70%HRR, and high intensity(HI): 70-80%HRR). The blood pressure(systolic(SBP) and diastolic blood pressure(DBP), blood lipids(total cholesterol(TC) and high-density lipoprotein cholesterol(HDL-C)) and fibrinolytic markers(tissue plasminogen activator(tPA) and plasminogen activator inhibitor-1(PAI-1)) were determined before(PRE), immediately after(POST) and 60minutes after the exercise(60 POST). Results: the SBP in the LI group was significantly increased at POST(p=0.013). The ES levels for the SBP in the MI and HI groups were reduced (-1.33 and -1.23, respectively), though the differences were not significant. The HDL in the MI(p=0.003) and HI(p=0.002) groups were significantly increased at 60 POST. Also, the tPA in the MI(p=0.021) and HI(p=0.042) groups were significantly increased at POST.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.3 s.246
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• pp.318-327
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• 2006

Due to the diversified use of recent Piezoelectric Zirconate Titanate Composite Actuate. (PZTCA), various PZTCAs with the different ply orientation of the fiber layer have been applied. For this reason, the applicable bending moment equation is necessary even though the fiber layer ply orientation and the laminate configuration are changed. The aim of this research is to evaluate the relationship between the total effective moment $(M^E)$ and Bernoulli-Euler bending moment (M) when the ply orientations of UD CFRP are changed. In conclusions, firstly, as the performance test results by the CFRP ply orientation, the performance of [0] and [90] were stable. However, while the performance of [+45] was suddenly decreased after 5 hours. Secondly, the change of $(M^E)$ by the CFRP ply orientation was evaluated. As the CFRP ply orientation was increased from [0] to [+60], the $(M^E)$ were gradually decreased. However, they became a little bit increased from [+60] to [90]. Finally, after the change of M by the CFRP ply orientation was evaluated, it was found that $M^E=2.2M$ was valid for just [0] and that there was a relationship between $M^E$ and M according to the ply orientation.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.7
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• pp.51-59
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• 2004

An experimental procedure to identify failure modes of impact damage using sensor signals and to analyze their general features is examined. A series of low-velocity impact tests from low energy to damage-induced high energy were performed on the instrumented drop weight impact tester to monitor the stress wave signals due to failure modes such as matrix cracking, delamination, and fiber breakage. The wavelet transform(WT) and Short Time Fourier Transform(STFT) are used to decompose the piezoelectric sensor signals in this study. The extent of the damage in each case was examined by means of a conventional ultrasonic C-scan. The PVDF sensor signals are shown to carry important information regarding the nature of the impact process that can be extracted from the careful signal processing and analysis.

• Journal of Sensor Science and Technology
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• v.21 no.2
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• pp.135-143
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• 2012

Arterial stiffness is causing the serious problems for human who is suffered from hypertension and metabolic syndrome. So it is important that measure the arterial stiffness for early prevention. Many researches point out that pulse wave velocity(PWV) is the reliable and simple method to predict arterial stiffness. In this paper, we developed the sensing parts that detect the pulse wave and ECG by using piezoelectric film and conductive textile with elastic band. Our system could detect 3ch pulse wave and ECG. Simultaneously, our algorithm extracts the features for calculating the delays among pulse waves. The delays are the significant parameter to estimate PWV, thus we design the experiment for evaluating the performance of our sensing parts. The reference is PP-1000(HanByul Meditech, Korea) that is good for performance evaluation. As a result, the start point of the pulse wave was the most reliable feature for comparing with PP-1000(r=0.691, P=0.00). The results between two operators showed that there is only a slight difference in the reproducibility of the devices. In conclusion, we assume that the suggested sensor could be more comfortable and faithful method for arterial stiffness.

• Journal of Convergence for Information Technology
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• v.11 no.11
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• pp.151-158
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• 2021

In this paper, we analyzed the latest research trends, challenges, and potential applications of next-generation solar cell materials in various industrial fields. In addition, future prospects and possibilities of Smart Textile Hybrid Energy Harvesting Devices that will supply electricity by combining with wearable IoT devices are presented. The hybrid textile energy harvesting device fused next-generation solar cells with tribo-piezoelectric devices will develop into new 'Convergence Integrated Smart Wear' by combining the material itself with wearable IoT devices in the era of the 4th industrial revolution. The next-generation nanotechnology and devices proposed in this paper will be applied to the field of smart textile with an energy harvesting function. And we hope it will be a paradigm shift that evolves into creative products which provide AI services such as medical & healthcare by convergence with the future smart wear industry.