• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.9
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• pp.1688-1693
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• 2007

The aim of this paper is to develop and verify the system which can detect heart rate during exercise by using conductive fabric electrode and transportable measurement module. The experiment was performed under 4 conditions(resting, walking, jogging, running) and 18 subjects data are used. By using the ECG measurement system used in cardiac stress testing as reference value in order to verify the accuracy of the developed system, the relative error and correlation coefficient was calculated for each subject at every 3 seconds. The results have shown that the high correlation between the developed system and the reference system for detecting heart rate during exercise. Relative error and correlation coefficient are 2.27% and 0.9877, respectively. 7 subjects data are omitted in these calculations because of severe noises. Therefore, it is expected that this system could be used as a health monitoring system in ubiquitous environment in the future.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.62 no.1
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• pp.50-55
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• 2013

Subjects with 0.7[clo]'s amount of clothing were estimated on their thermal comfort, concentrativeness, heart rate variability, stress and fatigue degree when given variation in relative humidity to 30, 40, 50, 60, 70, and 80[RH%], in an environmental test room of temperature 25[$^{\circ}C$], illumination 1000[lux] and air velocity 0.02[m/sec], by using EEG, learning ability and HRV. At the result, it was at 50~60[RH%] of relative humidity that subject's thermal comfort and concentrativeness were at the highest while stress were at the lowest, and it was at 60[RH%] of relative humidity that heart rate variability was most stabilized. It was found that when temperature and humidity of the environmental test room are at 25[$^{\circ}C$] and 50~60[RH%], subject's productivity and psychological state are least affected.

• Journal of Digital Convergence
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• v.12 no.1
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• pp.467-473
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• 2014

The purpose of this study is to monitor the physiological changes by measuring EEG, blood pressure, heart rate, etc after applying progressive relaxation technique to university archery players in order to verify the effect of progressive relaxation through respiration, and, ultimately, improve an athlete's archery performance. This study chose 13 female archery athletes. The EEG, blood pressure, and heart rate of the athletes were measured before applying Jacobson's progressive relaxation technique for 12 weeks, during which the EEG, blood pressure, and heart rate were measured 3 times a week after 15 to 20 minutes of training before every measurement. We used the SPSS18.0 program for technical analysis to check the general features of the athletes and carried out the paired t-test to examine the changes made to the EEG, blood pressure, and heart rate of a single test group before and after the experiment. All statistical level of significance was maintained at ${\alpha}=0.5$. The results are as follows. First, after 12 weeks of appliance, between the targets' relative ${\alpha}$ wave and ${\beta}$ wave, the relative ${\alpha}$ wave showed a statistically significant increase while the relative ${\beta}$ wave showed no changes. Second, after 12 weeks of appliance, in terms of blood pressure, the systolic pressure showed no changes while the diastolic pressure showed a statistically significant change. Third, there was no statistically significant change to the heart rate. In conclusion, progressive relaxation through breathing has a positive effect on the archery athletes.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 1998.11a
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• pp.88-93
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• 1998

The purpose of this study was to examine theory about indoor thermal comfort-environment as well as to determine thermal sensation and physical responses for men in summer and winter indoor environment, under various air temperature and relative humidity, with male university students. Subjective Evaluation, Heart rate(Electrocardiogram, ECG), Electroencephalo gram(EEG) were examined. We found that comfort of people was achieved at SET*. 24.7$^{\circ}C$, -0.82${\alpha}$-wave) both in summer and in winter.

• Journal of Haehwa Medicine
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• v.22 no.2
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• pp.81-92
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• 2014

Objective : The purpose of this study was to assess the effects of Cyperus rotundus L. essential oil on relaxation in highly stressed volunteers with heart rate variability(HRV) and electroencephalography(EEG). Methods : 11 highly stressed volunteers participated in this study. The volunteers were examined with HRV and EEG before and after inhalation of Cyperus rotundus L. essential oil. Results : After smelling Cyperus rotundus L. essential oil, mean RR(mean of RR intervals) was incresed significantly(p<0.01), mean HRV(mean of heart rate), HF(high frequency) were decreased significantly(p<0.01). norm LF(low frequency), LF/HF ratio were decreased significantly(p<0.05), norm HF(normalized high frequency) was increased significantly(p<0.05) on HRV. After smelling Cyperus rotundus L. essential oil, relative ${\theta}$ power was decreased significantly(p<0.05) at P3(left parietal) and relative ${\alpha}$ power was increased significantly(p<0.05) at Fp1(left prefrontal), Fp2(right prefrontal) and relative ${\beta}$ power was decreased significantly(p<0.05) at Fp1(left prefrontal) and relative ${\gamma}$ power was decreased significantly(p<0.05) at Fp1(left prefrontal) on EEG. Conclusions : This results show that inhalation of Cyperus rotundus L. essential oil effects on relaxation and decreasing stress.

• Proceedings of the Korean Fiber Society Conference
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• 1997.10a
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• pp.364-368
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• 1997

The purpose of this Study was to determine thermal sensation and physiological responses for men in summer indoor environment, under various air temperature and relative humidity, with male university students. Subjective Evaluation, Heart Rate Variability(HRV), Electroencephalogram(EEG) were examined. We found that comfort of people was achieved at 50% R.H., 24C, and the difference of skin temperature was found at the calf area as air temperature changes. At low air temperature and low humidity, heart rate was decreased, but there was no change at brain wave, keeping a-wave.

• Journal of the Korean Society of Clothing and Textiles
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• v.25 no.8
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• pp.1475-1483
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• 2001

The purpose of this study was to determine the physiological responses and subjective sensation according to fiber content of socks. Six female students participated in the wear trial test which was conducted in controled environmental chamber with 26${\pm}$1$^{\circ}C$ and 60${\times}$3%. R.H.SAS program was used for statistical analysis. The results of this study were as follows. Mean skin temperature was significantly different among three different socks. AWNP socks had the highest mean skin temperature and instep temperature. Also relative humidity in the microclimate of socks as well as heart rate were influenced by fiber content of socks, However, test of subjective sensation such as thermal, humid, comfort sensation showed that there was no significant difference among three different socks thermal sensation during the exercise and recovery period.

• Journal of Korea Multimedia Society
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• v.20 no.2
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• pp.234-243
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• 2017

With the development of smartphone technologies enable photoplethysmogram (PPG) acquisition by camera and heart rate (HR) measurement. This papers presents improved algorithm to extract HR from PPG signal recorded by smartphone camera and to develop real-time PPG signal processing Android application. 400 video samples recorded by Samsung smartphone camera are imported as input data for further processing and evaluating algorithm on MATLAB. An optimized algorithm is developed and tested on Android platform with different kind of Samsung smartphones. To assess algorithm's performance, medical device Beurer BC08 is used as reference. According to related works, accuracy parameters includes 90% number of samples that has relative errors less than 5%, Person correlation (r) more than 0.9, and standard estimated error (SEE) less than 5 beats-per-minutes (bpm).

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.10 no.3
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• pp.368-377
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• 1998

The purpose of this study was to examine theory about indoor thermal comfort-environment as well as to determine thermal sensation and physiological responses for men in summer indoor environment, under various air temperature and relative humidity, with male university students. Subjective Evaluation, Heart Rate(Electrocardiogram), Electroencephalogram(EEG) were examined. We found that comfort of people was achieved at SE $T^{*}$ 24.7$^{\circ}C$, -0.82＜PMV＜0.93, subject's clothing(0.41c1o)and the difference of skin temperature was found at the calf area as air temperature changes. At low SE $T^{*}$, heart rate was decreased and at high SE $T^{*}$, heart rate was increased but there was no change EEG(keeping $\alpha$-wave).wave).

• The Journal of Korean Physical Therapy
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• v.31 no.5
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• pp.322-327
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• 2019

Purpose: This study examined the influence of the maximal aerobic capacity on the two-year cardiac-related re-hospitalization in patients with heart failure with a reduced ejection fraction (HFrEF) in Korean society. Methods: The maximal aerobic capacity of the study population (n=95, male 63%) was evaluated using a cardiopulmonary exercise (CPX) testing system. Each patient was followed up for two years to divide the HFrEF patients into two groups according to cardiac-related re-hospitalization: re-hospitalization (RH) group (n=29, 30%) and no re-hospitalization (NRH) group (n=66, 70%). Results: The relative peak $VO_2$ (mL/kg/min, p<0.001), exercise duration (p<0.001), respiratory exchange ratio ($VCO_2/VO_2$, p=0.001), systolic blood pressure (SBP) reserve (p=0.004), heart rate (HR) reserve (p=0.007), SBP max (p=0.02), and HR max (p=0.039) were significantly lower in the RH group than the NRH group during the CPX test. On the other hand, the ventilatory efficiency (VE/VCO2 slope, p=0.02) and age (p=0.022) were significantly higher in the RH group than in the NRH group. In binary logistic regression analysis, the relative peak $VO_2$ (p=0.001, Wald Chi-square 10.137) was the strongest predictive factor on cardiac-related re-hospitalization, which was followed by $VCO_2/VO_2$ (p=0.019, Wald Chi-square 5.54). On the other hand, age (p=0.063, Wald Chi-square 3.445) did not have a significant influence on cardiac related re-hospitalization. Conclusion: The maximal aerobic capacity, especially the relative peak $VO_2$, is the strongest factor on cardiac-related re-hospitalization within two years in patients with HFrEF in Korean society.