• KIPS Transactions on Computer and Communication Systems
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• v.12 no.7
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• pp.227-234
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• 2023

Measuring heart rate variability by deep breathing and using this to evaluate the autonomic nervous system is a well-known method widely used in various clinical fields. In hospitals, expensive equipment is installed and managed by experts for this purpose. This paper discusses an app we developed that can easily test the autonomic nervous system by deep breathing anytime, anywhere using a smartphone, and then reviews experiments performed to verify the results. The experiments were conducted in the clinical room of the Department of Neurology at Soonchunhyang University Cheonan Hospital on eight volunteers. We tested the autonomic nervous systems of the volunteers first with an electromyography device installed in the hospital and then with the app under identical conditions. We performed a correlation analysis on the results of these two methods using the Pearson method, and this yielded a very high correlation of 0.98.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.55-56
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• 2018

In order to reduce the risk of accidents, we proposed a construction safety management system combined with wearable device and LoRa (Low-Range Wireless Network) communication method to apply the usefulness of Internet (IoT) technology which means "everything connected". to construction safety management Management system. The proposed wearable safety device is a device that relays information exchange between wearable safety device and safety management server by LoRa wireless communication method. The safety management server can store workers bio-data and perform big data analysis. If a risk factor is determined from the analysis result, a warning is sent to the wearable safety device and the manager's application. The goal of this system is to prevent construction workers from entering the dangerous area that is not suitable for work, and to prevent safety accidents caused by human cause by detecting abnormal condition during work.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2009.05a
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• pp.209-210
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• 2009

수면단계는 수면감성을 평가하는데 있어서 중요한 생리지표로서 사용되어왔다. 그러나 수면다원검사를 이용한 전통적 수면단계 분류방법은 뇌전도, 안전도, 심전도, 근전도 등을 종합적으로 측정하므로 수면단계를 비교적 정확히 분류할 수 있지만 피험자에게 심한 구속감을 주는 문제가 있다. 본 연구에서는, 각성상태에서 교감신경계가 지배적인 반면에 수면 중에는 부교감신경계가 더 활동적인 점에 착안하여 수면단계를 간단히 분류할 수 있는 방법을 찾고자 수면단계에 따른 심박동변이도(heart rate variability: HRV)를 분석하였다. 단일채널 심전도를 이용하여 수면단계별로 HRV 의 교감신경계/부교감신경계 활성도의 비율을 분석한 결과, W(wakefulness) 단계가 NREN(non REM) 2 단계, 3 단계, 4 단계에 비하여 높게 나타났으며, NREM 4 단계는 REM(rapid eye movement) 단계와 NREM 1단계에 비하여 낮게 나타났다. 또한 교감신경계/부교감신경계 활성도 비율의 수면단계에 따라 변화하는 양상은 W, REM, NREM 1, 2, 3, 4 단계의 순으로 단조 감소하였다.

• Korean Journal of Psychosomatic Medicine
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• v.28 no.1
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• pp.81-88
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• 2020

Objectives : This study aimed to compare autonomic nervous system (ANS) dysregulation and differential relationships with clinical severities between anxiety disorder, depressive disorder, and trauma·stressor related disorder using heart rate variability (HRV) parameters. Methods : We conducted a retrospective chart review of outpatients from 2017 to 2018 in Stress Clinic of National Center for Mental Health. Total 473 patients were included; 166 anxiety disorder; 184 depressive disorder ; 123 trauma·stressor related disorder. Parameters of 5-min analysis of HRV were compared in three groups. Additionally, we investigated the differential association of each parameters with Clinical Global Impression-Severity Scale (CGI-S) across each group. Results : No significant differences were found in all HRV parameters between the three groups. However, significant group interactions by CGI-S were found in standard deviation of all RR intervals (SDNN) and the square root of the mean squared differences of successive normal-to-normal intervals (RMSSD) (SDNN, p=0.017 ; RMSSD, p=0.034). A negative relationship between CGI-S and SDNN, RMSSD has been found in anxiety disorder and depressive disorder. However, a positive relationship between CGI-S and SDNN, RMSSD has been found in trauma·stressor related disorder. Conclusions : Despite of no significant differences of each HRV parameter, our findings suggested the differential associations of HRV parameters with clinical severity among anxiety disorder, depressive disorder and trauma·stressor related disorder. In trauma·stressor related disorder, the clinical severity and degree of ANS dysregulation may differ, so more aggressive treatment is suggested.

• 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.

• Journal of Korea Society of Industrial Information Systems
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• v.20 no.3
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• pp.11-18
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• 2015

Stress is one of the major causes threatening the mental and physical health of human today. In this paper, we analyzed the heart rate variability(HRV), galvanic skin response(GSR), and skin temperature data measured from the university subjects before and after the class to examine the influence on bio-signal in stress environment. Thirty subjects from university students (aged between 21 and 27 years; mean=22.31, STD=1.45) took part in this study. From the experiment results, RMSSD(p=0.033), LF peak(p=0.003), VLF(p=0.045) were statistically significant from those of the control group(p<0.05) of HRV both in time and frequency domain. We observed that mean skin conductivity after the class(mean=5.993(uS), SD=3.406) is higher than that before the class(mean=3.039(uS), SD=2.628) by 97.2% on average and the skin temperature after the class($34.835{\pm}0.305$) is slightly higher than that before the class($34.471{\pm}0.281$) by 1.055% on average. The results in this research could be used to examine the autonomic response in clinical stress related research.

• Journal of Digital Convergence
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• v.14 no.4
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• pp.363-370
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• 2016

Noise is unwanted sound that is the reason of the stress and hearing loss. The current study attempted to estimate whether the noise of dental laboratory affected stress and pure tone audiometry (PTA) of dental laboratory technicians (DLTs) using heart rate variability, air and bone conduction audiometry. The age, heights, and weights of DLTs were resembled control. Standard deviation of normal to normal interval such as stress resistance and normalized HF of DLTs were significantly decreased, but heart rates, normalized LF, and LF/HF ratio of DLTs were significantly increased compared with control. In air conduction audiometry of DLTs, significant increments of thresholds encountered in 125, 250, 500, 1000, 2000, 3000, 4000, and 6000 Hz in the right ears and 125, 250, 500, 1000, and 2000 Hz in the left ears. Thresholds of bone conduction audiometry in both ears were significantly increased in 250, 500, 1000, 2000, and 4000 Hz. The findings in this study provide that stress and hearing loss observed in noise-exposed DLTs at dental laboratory. Therefore, proper safety precautions should be carried out at dental laboratory.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.46 no.1
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• pp.1-9
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• 2009

In this paper, a 2.4 GHz doppler radar system consisting of a doppler radar sensor and a baseband module were designed to detect heart beat and respiration signal without direct skin contact. The doppler radar system emits RF signal of 2.4 GHz toward human chest, and then detects phase modulation of the reflected signal so as to investigate cardiopulmonary activities. The heartbeat and respiration signals acquired from I/Q channels of the doppler radar system are applied to the pre-processing circuit, the amplification circuit, and the offset circuit of the baseband module. The designed system was tested on mouse, rabbit and mankind, which have different range of heart rates and respiration signals, to evaluate detection accuracy of the system. ECG acquisition system and respiration transducer were used to generate the reference signal. In our experiments, a performance of detection were found to be high in the case that the subject stays still. In this paper, we confirmed that non-contact heart beat and respiration detection using the doppler radar has the possibility and limitation according to distance, cardiopulmonary activities, range of heart rates and respiration.

• Science of Emotion and Sensibility
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• v.6 no.4
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• pp.41-49
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• 2003

To inspect how the different sensitivities in BAS(or BIS) modulate on the HRV pattern stimulated by positive or negative affective sound, we measured the electrocardiogram(ECG) of 25 students(male : 14), consisted of 4 groups depending on the BAS(or BIS) sensitivity, during listening meditation music or being exposed to noise. The power spectral density(PSD) of HRV was derived from the ECG, and the power of HRV was calculated for 3 major frequency ranges(low frequency[LF], medium frequency[MF], and high frequency[HF]). We found that the index of MF/(LF+HF), during listening music, was higher significantly in the individuals with a low BIS but high BAS than in the individuals with a low sensitivity in both BIS and BAS. Especially in the former group, there was a tendency that the index was higher during listening music than during being exposed to noise. For individuals with a high BIS, regardless of the BAS sensitivity, the difference of this index values was not significant. From these results we suggest that individuals with a low BIS but high BAS are more sensitive to positive affective stimuli than other groups, and the index of MF/(LF+HF) is applicable to evaluate positive and negative affects.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 1999.03a
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• pp.243-248
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• 1999

There is substantial evidence that anatomical connections and functional interactions exist between vestibular and autonomic systems. Heart rate variability (HRV) including mean, standard deviation, coefficient of variation (CV), power spectrum was analyzed for evaluation of the physiological role of the vestibular system on control of heart rate in rabbits. In anesthetized rabbits, electrical stimulation of the vagus nerve decreased heart rate and decreased LF/HF by increasing HF. On the cervical sympathetic nerve increased heart rate and increased LF/HF by increasing LF. Atropine, cholinergic blocker, increased heart rate and increased LF/HF by reducing HF, and propranolol, ${\beta}$-adrenergic blocker, decreased heart rate and decreased LF/HF by reducing LF> In unanesthetized rabbits, stimulation of the vestibular system induced by rotation or caloric increased heart rate and increased LF/HF by increasing LF> Also electrical stimulation of the vestibular nerve produced the same of effects as rotation or caloric in anesthetized rabbits. These results suggest that Stimulation of the vestibular system increased heart rate not by inhibiting the parasympathetic nerve but by activating the sympathetic nerve.