• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.2010-2012
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• 2008

This study describes a system for human sensibility evaluation using PPG(photoplethysmogram) signal and biofeedback algorithm to respond the bad(negative) mood. For this objective, PPG signals for two emotional states(positive/negative) are collected. To evoke the test emotions, happy(or joyful) and sad(or irritating) movie files are collected and played in subjects' monitor. From the acquired PPG signal, the heart rate variability(HRV) is calculated. Using the HRV and its FFT spectra, the human sensibility is evaluated. Since the heart is a representative organ which is controlled by the autonomic nervous system(ANS), the ANS may reflect the changes in emotion. The biofeedback algorithm is designed with motion image player interacting with the results of the sensibility evaluation. It was shown that HRV was changed according to the subject's emotions. Accordingly, the sensibility evaluation test showed feasibility of the our method.

• Journal of Acupuncture Research
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• v.23 no.3
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• pp.155-163
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• 2006

Objectives : This study was designed to evaluated the effect of electro acupuncture on Heart Rate Variability of Patients with functional voiding disease. Methods: Subjects were voluntarily recruited by newspapers and internet. Electro acupuncture was performed three times a week for 3 weeks. Acupuncture point for EA group was B32, Electrical stimulation frequency was 2Hz, duration 20min, and intensity was up to pain threshold according to patients. The patients' Heart Rate Variability was measured before, after 3 weeks of treatment for 5 minutes. Results : In time domain analysis, There were significant increase of SDNN and RMSSD(p<0.05) after 3 weeks treatment. In frequency domain analysis, There were significant increase of LF and LF /HF ratio(p<0.05) after 3 weeks treatment. There were no significant changes in other components of heart rate variability. Conclusion : This study suggests that electroacupuncture treatments can be applicable to improve autonomic nervous system in patients with functional voiding disease.

• Korean Journal of Acupuncture
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• v.33 no.4
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• pp.176-182
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• 2016

Objectives : This study was designed to analyze the characteristic of heart rate variability(HRV) changes between Deficiency Pattern and Excess Pattern in Stroke Patients admitted to the hospital. Methods : We measured heart rate variability of stroke patients who were admitted to the Department of Korean Internal medicine, Stroke and Neurological Disorders Center from February 1, 2015 to May 30, 2016. We recruited a total of 28 stroke patients and heart rate variability tests were performed on the first day of admission, 2weeks after admission, and 4 weeks after admission. Results : VLF and LF/HF ratio significantly increased over time in Deficiency Pattern group compared with those in the Excess Pattern group. Conclusions : This results suggest that the parasympathetic function of Deficiency Pattern group is lower than that of the Excess Pattern group, resulting in imbalance of the autonomic nervous system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.148-151
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• 2010

심장관련 질환은 현대사회에서 업무 과중과 스트레스에 의해 발병 가능성이 높아지고 있으며, 일상생활 중 건강상태를 지속적으로 모니터링하여 심장질환 관련 응급상황에 대처하기위한 많은 연구들이 수행되고 있다. 본 연구에서는 가정 또는 사무실에서 무구속적인 방법으로 지속적인 심장 활동상태의 모니터링이 가능한 무구속 의자형 심탄도 계측 시스템을 구현하였다. 구현된 시스템에서 계측된 심탄도 신호로부터 건강모니터링을 위한 특징성분을 검출하기위해 웨이브렛 변환과 템플릿 매칭을 혼합한 신호처리방법을 제안하였다. 또한 적응 문턱치를 통해 심탄도 신호에서 심박동을 검출하였으며 심박동의 간격으로부터 HRV(heart rate variabillity)를 계산하였다. 구현된 시스템의 성능평가를 위하여 심전도와 동시에 심탄도를 측정하였으며, 두 신호로부터 심박동 검출 성능을 비교하여 구현된 무구속 의자형 심탄도 계측 시스템의 유용성 및 무자각 건강모니터링의 가능성을 확인하였다. 또한 스트레스에 따른 HRV의 변화를 관찰하기 위하여 피실험자로부터 인위적으로 숨을 참고 강제호기를 통해 흉강내압을 증가시켜 인위적인 육체적 스트레스를 가하는 발살바를 유도하였으며, HRV의 시간 및 주파수 영역에서 도출되는 파라미터들을 평가하여 심탄도 모니터링을 통해 안정 상태와 스트레스 상태의 판별 및 무구속 건강모니터링의 가능성을 평가하였다.

• Journal of Physiology & Pathology in Korean Medicine
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• v.27 no.3
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• pp.318-326
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• 2013

This study was performed to investigate relationship between each pattern identification and heart rate variability(HRV) indices. We analyzed 201 subjects who participated in stroke check up. We classified the subjects into four groups of pattern identifications; Fire-Heat pattern(FH), Yin Deficiency pattern(YD), Qi Deficiency pattern(QD) and Dampness-Phlegm pattern(DP) that based on Korean Standard Pattern Identifications for Stroke-III. We investigated significance of HRV indices between each pattern identification and heart rate variability indices. The total number of the subject group was 201, whereas the groups were divided into four groups; Fire-Heat pattern group(n=47), Yin Deficiency pattern(n=65), Qi Deficiency pattern(n=33), and Dampness-Phlegm pattern(n=56). SDNN, TP, Ln(TP), VLF, Ln(VLF), LF, Ln(LF) and HF were significantly higher in the Fire-Heat pattern(FH) group than other groups of pattern identifications, but there was no differences among the Yin Deficiency group, the Qi Deficiency group and the Dampness-Phlegm group. Ln(HF), LF(NORM), HF(NORM) and LF/HF ratio were significantly higher in the Fire-Heat group than in the Qi Deficiency group. However, there was no significant differences among the Dampness-Phlegm group, the Yin Deficiency group, Fire-Heat group and the Qi Deficiency group. Through this study, we found out some significant relationships between each pattern identification group and HRV indices. The result of this study demonstrates that sympathetic nerve was more active in the Fire-Heat group than other groups.

• Journal of the Korean Data and Information Science Society
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• v.28 no.6
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• pp.1383-1402
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• 2017

This study aims to investigate the effects of aroma inhalation on pain, anxiety, and heart rate variability of elderly women with total knee arthroplasty (TKA) during continuous passive motion (CPM) exercise. Equivalent control group pretest-posttest design was used. Participants were randomized to intervention group (n=26) or control group (n=27). Participants inhaled aroma or distilled water for 5 minutes before CPM exercise and for 40 minutes during CPM exercise on 3 consecutive days. Pain NRS, number of painkiller used, anxiety NRS, blood pressure, and heart rate variability (HRV) were measured before and after intervention. Pain NRS, anxiety NRS, blood pressure in experimental group were significantly lower than those of control group. All indices of HRV were significantly different between the two groups. Based on these results, it can be concluded that aroma inhalation was effective in decreasing pain and anxiety and changing HRV among elderly women with TKA during CPM exercise.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.3
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• pp.136-142
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• 2014

Distinct features in heart rate signals during the driver's wake and sleep states could provide an initiative for the development of a safe driving systems such as drowsiness detecting sensor in a smart wheel. We measured ECG from health subjects ($23.5{\pm}2.5$ in age) during the wake and drowsiness states. The proposed method is able to detect R waves and R-R interval calculation in the ECG even when the signal includes in abnormal signals. Heart rate variability(HRV) was investigated for the time domain and frequency domains. The STD HR(0.029), NN50(0.044) and VLF power(0.0018) of the RR interval series of the subjects were significantly different from those of the control group (p < 0.05). In conclusion, there are changes in heart rate from wake to drowsiness that are potentially to be detected. The results in our study could be useful for the development of drowsiness detection sensors for effective real-time monitoring.

• Journal of the Korea Convergence Society
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• v.9 no.5
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• pp.33-41
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• 2018

The purpose of this study is to develop more accurate and robust emotion prediction neural network (EPNN) model by combining heart rate variability (HRV) and neural network. For the sake of improving the prediction performance more reliably, the proposed EPNN model is based on various types of activation functions like hyperbolic tangent, linear, and Gaussian functions, all of which are embedded in hidden nodes to improve its performance. In order to verify the validity of the proposed EPNN model, a number of HRV metrics were calculated from 20 valid and qualified participants whose emotions were induced by using money game. To add more rigor to the experiment, the participants' valence and arousal were checked and used as output node of the EPNN. The experiment results reveal that the F-Measure for Valence and Arousal is 80% and 95%, respectively, proving that the EPNN yields very robust and well-balanced performance. The EPNN performance was compared with competing models like neural network, logistic regression, support vector machine, and random forest. The EPNN was more accurate and reliable than those of the competing models. The results of this study can be effectively applied to many types of wearable computing devices when ubiquitous digital health environment becomes feasible and permeating into our everyday lives.

• Science of Emotion and Sensibility
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• v.21 no.1
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• pp.71-82
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• 2018

Stress involves changes in behavior, autonomic function and the secretion of hormones. Autonomic nervous system (ANS) contributes to physiological adaptive process in short durations. In particular, heart rate variability (HRV) analysis is commonly used as a quantitative marker depicting the ANS activity related to mental stress. The aim of this study is to investigate correlations between psychological responses to stress and HRV indices induced by the cognitive stressor. Thirty-three participants rated their mental and physical symptoms occurred during the past two weeks on Stress Response Inventory (SRI), which is composed of seven stress factors that may influence the status of mental stress levels. Then, they underwent the psychophysiological procedures, which are collected electrocardiogram (ECG) signals during a cognitive stress task. HRV indices, the standard deviation of R-R interval (SDNN), root mean square of successive R-R interval difference (RMSSD) and low frequency (LF)/high frequency (HF) ratio were extracted from ECG signals. Physiological responses were calculated stress responses by subtracting mean of the baseline from the mean of recovery. Stress factors such as tension, aggression, depression, fatigue, and frustration were positively correlated to HRV indices. In particular, aggression had significant positive correlations to SDNN, RMSSD and LF/HF ratio. Increased aggressive responses to stress correlated with the increases of all HRV indices. This means the increased autonomic coactivation. Additionally, tension, depression, fatigue, and frustration were positively associated with RMSSD reflecting increases in parasympathetic activation. The autonomic coactivation may represent an integrated response to specific cognitive reactions such as the orienting response.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.1395-1396
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• 2010