• The Journal of Internal Korean Medicine
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• v.19 no.2
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• pp.7-16
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• 1998

Background and Purpose The increasing evidence for neurally mediated cardiac damage and sudden death has focused attention on the central autonomic control of cardiac function. Power spectral analysis of heart rate variability(HRV) can detect autonomic consequences of stroke. We performed power spectral analysis of heart rate variability from 24-hour holter recording to identify cerebral hemispheric lateralization and gender effect in cardiac autonomic control. Methods Data were obtained from 24-hour holter recordings in 30 consecutive patients with hemispheric brain infarction in the subacute phase. We analysed the time domain and frequency domain measures of HRV and ST segment by hemispheric lateralization and Gender. Results ST segment was depressed in women compared with man. There was no statistically significant differences between right and left hemisphere stroke patients in any standard index of HRV and ST segment changes. Conclusions These data are partial consistent with evidence from the recent literature that two cerebral hemispheres and gender have a differential influence on the nature and severity of cardiac dysfunction. We think the prospective and definite study was necessary.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.9
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• pp.2460-2470
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• 2009

In this study, the parameter extraction for evaluation of the anesthesia depth in each anesthesia stages was conducted. An object of the this experiment study has studied 5 adult patients (mean $\pm$ SD age:$42{\pm}9.13$), ASA classification I and II, undergoing surgery of obstetrics and gynecology. Anaesthesia was maintained with Enflurane. HRV signal was created by R-peak detection algorithm form ECG signal. The HRV data were preprocessing algorithm. It has tried find out the anesthesia parameter which responds the anesthesia events and shows objective anesthesia depth according to anesthesia stage including pre-anesthesia, induction, maintenance, awake and post-anesthesia. In this study, proposed algorithm to analysis the HRV(heart rate variability) signal using wavelet transform in anesthesia stage. Three sorts of wavelet functions applied to PSD. In the result, all of the results were showed similarly. But experiment results of Daubeches 10 is better. Therefore, this parameter is the best parameter in the evaluation of anesthesia stage.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2002.05a
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• pp.177-180
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• 2002

The type of physiological stress involved in driving is probably complex, and a comprehensive study involving recording of physiological signals such as electrocardiogram(ECG), electromyogram(EMG). Changes in relevant Physiological parameters, such as ECG, EMG, reflected changes in driver status. In order to derive the mental and physical load of driving a motor vehicle from driving behaviour alone it is necessary to establish the relationship between changes in a driver's physiological parameters and behavioral parameters. In this study, we choose two different condition and investigated driver's status using HRV analysis method. Many previous studies have shown that increasing driving time causes a variation of HRV signal.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 1998.04a
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• pp.270-274
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• 1998

HRV(heart rate variability)분석에 있어서 LF와 HF변수들은 교감신경계나 부교감신경계와 같은 인체내 자율신경계의 반응을 나타내는 유용한 지표로 사용되어져 왔다. 따라서 본 연구에서는 피험자나 실험환경의 상대적인 차이를 고려하여 상하온도차에 따라 변화하는 자율신경계의 반응을 HF/LF변수비를 통해 조사하였다. 전반적인 실험결과를 볼 때, 머리의 온도가 23˚인 경우 두한족열이 두열족한에 비해 HF/LF수치값이 대체로 높은 양상을 보여주었다. 두열족한의 경우 머리/발 온도가 $25^{\circ}C$/19$^{\circ}C$인 경우와 일부피험자를 제외한 27$^{\circ}C$/12$^{\circ}C$조건에서 높은 수치결과를 나타내었고, 두한족열에 있어서는 머리/발 온도가 2$0^{\circ}C$/26$^{\circ}C$인 경우와 23$^{\circ}C$/26$^{\circ}C$인 경우에 전반적으로 높은 수치결과를 보여주었다.

• Journal of the Korea Safety Management & Science
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• v.14 no.3
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• pp.85-92
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• 2012

In this study the real situation of apartment house in seoul is reproduced with multi-zone modeling program contam2.4. This model include immune building system(disinfection system) which is consist of dilution, Filter Technology and UVGI(ultra violet germicidal irrdiation). In this study experiments design method used for estimating interaction of HRV air change rate, UVGI air change rate and UVGI grade. Result show that HRV air change rate and UVGI air change rate is most influence factor for remove rate. also Interaction of HRV air change rate and UVGI air change rate is ost influence factor for remove rate.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.2
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• pp.103-117
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• 2010

In this study, the heart rate variability(HRV) signal of operating patient was acquired according to anesthesia progress and identified to evaluation possibility of depth of anesthesia in each anesthesia stage. The HRV signal was analyzed time-frequency domain applied to Wigner-Ville distribution method, the characteristic parameters were extracted for evaluation of depth of anesthesia in each anesthesia stage. The progress of general anesthesia was divided into the states of pre-operation, induction of anesthesia, operation, awaking and post-operation.

• Journal of Korea Multimedia Society
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• v.21 no.12
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• pp.1370-1378
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• 2018

There is a problem to measure neutral bio-signals during sleep because of inconvenience of attaching lots of sensors. In this study, we measured single electrocardiogram(ECG) signal and analyzed the correlation with sleep. After R-peak detection from ECG signal, we extracted 9 features from time and frequency domain of heart rate variability(HRV). Mean of HRV, RR intervals differing more than 50ms(NN50), and divided by the total number of all RR intervals(pNN50) have significant differences in each sleep stage. Specially, the mean HRV has an average of 87.8% accuracy in classifying sleep and awake status. In the future, the measurement ECG signal minimizes inconvenience of attaching sensors during sleep. Also, it can be substituted for the standard sleep measurement method.

• The Journal of Pediatrics of Korean Medicine
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• v.26 no.3
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• pp.1-11
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• 2012

Objectives The purpose of this study is to examine the relationship between skeletal maturity and heart rate variability (HRV) based on the bone age and HRV parameters. Methods 103 children from 6 years to 17 years of age, who do not have any disease-related symptom, and visited ${\bigcirc}{\bigcirc}$ oriental medicine hospital, are measured based on their bone age and short-term spectral analysis of HRV. Results 1. Skeletal maturity was significantly correlated with HRV indices: mean HRT and SDNN. As the skeletal maturity increases, the mean HRT was decreased and the SDNN was increased. 2. When classifying according to the skeletal maturity score, the mean HRT was higher in the 'below -0.4' group compare to '-0.3~0.7' group and '0.8~1.9' group. SDNN was higher in the '0.8~1.9' group compare to '-0.3~0.7' group, 'below -0.4' group 3. When classifying according to the sex, age and secondary sexual characteristics, as the skeletal maturity was increased, the mean HRT was significantly decreased and the SDNN was significantly increased only in the boys who did not develop secondary sexual characteristics. Conclusions Skeletal maturity could be statistically significant with HRV indices, especially to the boys and the children than the girls and the teenagers.

• Journal of Biomedical Engineering Research
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• v.33 no.3
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• pp.141-147
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• 2012

In this paper, we have investigated effects of two specific meditations (Chinese qigong meditation and Kundalini yoga meditation) on the heart rate variability (HRV), which is a well-known quantitative measure of autonomic balance, of skilled students. To analyze the effects, the MIT/BIH physionet database was utilized. The database includes RR intervals of eight skilled Chinese qigong meditators (5 women and 3 men; age range 26-35) and four skilled Kundalini yoga meditators (2 women and 2 men; age range 20-52). RR intervals of each subject were measured before and during the meditations. For HRV analysis, we have used typical four HRV parameters - the low frequency to high frequency power ratio (LF/HF ratio), SD2/SD1 ratio, sample entropy, and fractal dimension. The LF/HF ratio was calculated by the autoregressive spectrum and the SD2/SD1 ratio was derived from the Poincar$\grave{e}$ plot. The sample entropy was computed from the phase space plot and the fractal dimension was estimated by the Higuchi's algorithm. In the experiments, the Wilcoxon signed rank test was employed because we used small datasets and compared HRV parameters before and during the meditations. As a result, we have found increment of the LF/HF and SD2/SD1 ratios in both meditations; whereas the sample entropy is decreased during the meditations. In addition, the fractal dimension is increased during the Chinese qigong meditation; whereas it is decreased during the Kundalini yoga meditation. The results show that the sympathetic nervous system is generally more activated in skilled Chinese qigong and Kundalini yoga meditators, but the activation of the parasympathetic nervous tone is suppressed.

• Journal of the Korea Society of Computer and Information
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• v.16 no.2
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• pp.17-23
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• 2011

In this paper, daily life stress monitoring system is proposed. The proposed wireless ECG module, reducing the noise and increasing the size of signal, amplification circuit was designed for. Using HRV(Heart Rate Variability), extracted by measuring R-wave, stress diagnostic algorithms to assess the stress of human emotion were developed. For monitoring the activities, the proposed system is consist of small rectangular size for portable and by simple measurement it is possible to measure at any time. Through experiments, the proposed approach to represent user's stress level can be confirmed. Through that, it can see appropriate structure to obtain R-wave for stress assess as well as high resemblance to the clinical electrocardiogram. In this paper, performed experiments was developed nonrestraint measuring and wearable wireless biometric scanner that is able to monitor the heart's electrical activity of everyday life.Using this, the algorithm system, that is able to assess stress index through time-domain and frequency-domain analysis of the front and the rear of performing stress load protocol, was developed,