• 대한인간공학회지
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• 제22권2호
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• pp.15-28
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• 2003

The one of the most important factors is the platoon design on developing AH3(Advanced Highway System), as it is related to traffic efficiency and drivers' safety. This study was evaluated that how much speed is comfortable for drivers and how long distance is appropriate for vehicular gap of platoon by measuring drivers' physiology signal and sensibility. A fixed-based AHS simulator was developed by using a real vehicle cockpit and the restructured part of Korean highway for human factors evaluation. The EEG(electroencephalogram), ECG (electrocardiogram) and GSR(Galvanic Skin Response) were measured for obtaining drivers' physiology signal according to the change of speed and gap. The brain wave(${\alpha},\;{\beta},\;{\delta},\;{\theta}$) by EEG, the response of the autonomic nervous system. the sympathetic and parasympathetic nervous system, by ECG, and relax-arousal situation by GSR were analyzed. The SD(Semantic Differential) method was also applied to evaluate drivers' sensibility by 5-grade evaluation scale with 96 adjectives. SSQ(Simulator Sickness Questionnaire) was used to measure the simulator sickness of pre and post driving, two times. As the results, drivers were comfortable with 120km/h speed of platoon and lam to 15m vehicular distance. The results of this study may differ from the adaption of the reality because of many parameters. However, the purpose of this study is show to significant results of the drivers' safety and the acceptability of human factors evaluation.

• 전기학회논문지
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• 제65권3호
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• pp.493-498
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• 2016

Heart Rate Variability (HRV) represents beat-to-beat fluctuations of R-R intervals in Electrocardiogram (ECG). On of the clinical applications of HRV is to assess the mental-stress state by evaluating its power spectral density distribution. This study aims at finding new discriminative role of the coupled-oscillating coupling constants, Cs and Cp in the Integral Pulse Frequency Modulation (IPFM) model. Based on comparing with power spectral density of HRV in terms of the relative ratio of the low and high-frequency power component, we can conclude the fact that the coupling parameters Cs and Cp can replace the role of HRV power spectrum interpretation for judging the mental-stress state.

• 센서학회지
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• 제20권2호
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• pp.118-123
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• 2011

Heart related diseases mainly caused by heavy work load and increasing stress in human daily life. Therefore, researches on mobile healthcare monitoring for daily life has been carried out. Notably, wearable healthcare monitoring system which has least restriction has been tried to provide an emergency alert of abnormal heart rate. In this study, we developed chair type unconstrained BCG measurement system which able to perform continuous heart status monitoring at the office and daily life in the unconstrained way. Furthermore, adaptive threshold is used to detect the heart rate from BCG signals. The HRV(heart rate variability) is calculated from heart rate interval. ECG signal measured using conventional method and BCG signal measured using unconstraint system are carried out simultaneously for the purpose of performance evaluation. From the comparison result, BCG signal shows a similar heart beat characteristic as ECG signal. This proves the possibility of practical implementation of unconstraint healthcare monitoring system. In addition, medical examination like valsalva maneuver is performed to observe the changes in HRV due to stress. By performing valsalva maneuver, heart is said to be placed under an artificial physical stress condition. Under this artificial physical stress condition, the time and frequency domain of HRV parameters are evaluated.

• 한국콘텐츠학회논문지
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• 제18권2호
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• pp.370-377
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• 2018

집중도는 사용자 연구에서 중요한 감성적 반응으로 고려되고 있다. 객관적인 측정 방법으로 심장반응을 이용하여 데이터화 한다면 집중도를 감시할 수 있다. 본 연구의 목적은 상호작용을 하는 상황에서 유발되는 집중도의 차이에 따른 심장 반응의 패턴 분석을 통해 객관적이고 정량적으로 집중도를 인식하는 방법을 개발하는 것이다. 대학생 피험자 60명이 집중도 실험에 참여하였고 실험하는 동안 피실험자들의 심전도를 측정하였다. 실험은 화살로 타겟을 맞추는 게임으로 쉬운 난이도와 어려운 난이도로 구성하였다. 심전도로 부터 시간 영역 인디케이터와 주파수 영역 인디케이터를 추출하였다. 독립 표본 t검정 결과, 심전도로부터 추출한 시간 영역 인디케이터인 RRI와 SDNN, rMSSD, pNN50에서 집중도 차이에 따라 통계적으로 차이가 유의미하였다. 주파수 영역 인디케이터에서는 LF와 HF, lnLF, lnHF가 집중도 차이에 따라 통계적으로 차이가 유의미하였다. 이 중 집중도의 차이에 따라 패턴의 차이가 큰 RRI와 rMSSD, lnHF를 선정하여 통합 인디케이터를 생성하였다. 통합 인디케이터를 통해 도출한 룰베이스를 낮은 집중과 높은 집중 60개의 데이터 샘플을 통해 검증한 결과, 95%로 높은 인식 정확도를 보였다. 본 연구에서 제안한 집중도 인식 방법을 콘텐츠를 비롯한 다양한 분야에 적용하여 집중도를 높일 수 있는 컨텐츠적 요소들을 개발한다면 효율 및 흥미를 증진시킬 것이라 기대된다.

• 대한의용생체공학회:의공학회지
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• 제30권2호
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• pp.129-134
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• 2009

The ideal method which measures a blood vessel of senility and degree of arteriosclerosis is to measure compliance of arterial and condition of blood circulation at the periphery. In these days vascular stiffness have been assessed by analyzing PTT (pulse transit time) from ECG and PPG. PTT is that between toe and finger each subject estimated through ECG and PPG signals. Two parameters, which are related to PWV, were tested with the time delay between the finger and toe. PWV is a variation of quantity which is associated with vascular stiffness. These researches which use PTT and PWV don't consider the blood vessel characteristic of an individual. In this current research, we have used with the blood vessel characteristic of an individual. That is an assessment of vascular stiffness using the variation of quantity in PWV with the changes of position in the subject. PWV variation increased as functions of the subject's age. The increase of the PWV variation parameters with age is attributed to the direct decrease of the blood vessel compliance with different position. The quantity of variation estimated by experimental results is that old age's (75.78${\pm}$7.75) case is 113.68% and young age's (26.47${\pm}$2.04) case is 85.69%. We proved and presented about estimation of vascular stiffness of possibility by this result.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 V
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• pp.2745-2748
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• 2003

In this paper, we implement the photoplethysmo-graphy system that have three channel pulse wave detects and one channel ECG amplifier. In order to detect the artery state, we measured the pulse waves at different positions, simultaneously. In general, arterial vascular system suffers the decrease of compliance, increase of resistance, and decrease of distensibility through aging. Therefore, we compared and analyzed variation of tile Pulse waves parameter both in time and frequency domains that is concerned with the changes of arterial characteries. And then evaluated the correlation coefficients between the parameters variation and the age group. As the result of experiment, we found that the Parameters have a significant correlation about aging.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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• pp.87.1-87.1
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• 2003

With the issuance of the ICH “Guidance for industry S7A Safety Pharmacology Studies For Human Pharmaceuticals” in July 2001 came the preference for the use of unanesthetized animals when evaluation the safety profile of new pharmaceutical agents. Telemetry provides a means of obtaining measurements of physiological functions in conscious animals without the problems associated with classical cardiovascular measuring methods. The Korea Institute of Toxicology (KIT) established the telemetric measurement of cardiovascular parameters, such as Blood pressure, Heart rate, ECG (PR, RR, QRS, QT and QTcB interval) under GLP conditions. (omitted)

• Tuberculosis and Respiratory Diseases
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• 제73권3호
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• pp.151-161
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• 2012

Background: Adequate assessment and control of sedation play crucial roles in the proper performance of mechanical ventilation. Methods: A total of 30 patients with various pulmonary diseases were prospectively enrolled. The study population was randomized into two groups. The sedation assessment group (SAG) received active protocol-based control of sedation, and in the empiric control group (ECG), the sedation levels were empirically adjusted. Subsequently, daily interruption of sedation (DIS) was conducted in the SAG. Results: In the SAG, the dose of midazolam was significantly reduced by control of sedation (day 1, $1.3{\pm}0.5{\mu}g/kg/min$; day 2, $0.9{\pm}0.4{\mu}g/kg/min$; p<0.01), and was significantly lower than the ECG on day 2 (p<0.01). Likewise, on day 2, sedation levels were significantly lower in the SAG than in the ECG. Significant relationship was found between Ramsay sedation scale and Richmond agitation-sedation scale (RASS; $r_s$=-0.57), Ramsay Sedation Scale and Bispectral Index (BIS; $r_s$=0.77), and RASS and BIS ($r_s$=-0.79). In 10 patients, who didn't require re-sedation after DIS, BIS showed the earliest and most significant changes among the sedation scales. Ventilatory parameters showed significant but less prominent changes, and hemodynamic parameters didn't show significant changes. No seriously adverse events ensued after the implementation of DIS. Conclusion: Active assessment and control of sedation significantly reduced the dosage of sedatives in patients receiving mechanical ventilation. DIS, conducted in limited cases, suggested its potential efficacy and tolerability.

• 감성과학
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• 제12권2호
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• pp.161-168
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• 2009

본 연구에서는 무구속, 무자각, 무침습적인 패치형 심장활동 모니터링 시스템(HAMS)을 개발하였다. 이 심전도 모듈은 무선 통신을 사용하여 신호를 컴퓨터로 전송 받아 실시간으로 피검자의 심장 활동 상태를 언제 어디서나 장시간 동안 손쉽게 모니터링 측정할 수 있는 이동성을 갖추고 있다. 가슴에 부착이 가능한 패치 타입의 소형 전극을 자체 제작하였고, 측정된 심전도 신호에 대한 신뢰성 검증이 이루어졌다. HRV에 대한 스트레스의 영향을 평가하기 위하여 HAMS을 이용하여 동일한 피험자를 대상으로 HRV 파라미터와 불안, 스트레스 항목에 대한 설문지 평가, 스트레스 호르몬(코티졸)양을 측정하였다. 일상 상태와 스트레스 상황에서의 값들을 비교한 결과, 많은 파라미터에서 유의미한 차이가 나타났다. 또한 피어슨 상관계수로부터 스트레스와 상관성이 높은 파라미터를 검토하였다. 이는 HAMS를 이용하여 자율신경계 기능 평가가 충분히 가능하다는 것을 보여주는 것이다. 이러한 결과로부터 HAMS를 통하여 일상생활에서 심장 이상을 예측할 수 있으며, 건강 모니터링 시스템으로 활용도가 높을 것으로 기대된다.

• Journal of Preventive Medicine and Public Health
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• 제37권2호
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• pp.182-189
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• 2004

Objectives : The objective of this study is to compare the circadian patterns of heart rate variability assessed by 24-hour ambulatory electrocardiographic (ECG) recordings during day shift and night shift among the workers in the 5 days-concecutive-12-hour shift in an automobile factory in Korea. Methods : The study population consisted 300 workers, who were randomly selected among the 8700 total workers in one car factory. To analyse circadian variation, the 24-hour ECG recordings (Marquette) were measured during day shift (08:00-20:00 h) and night shift (20:00-08:00 h). Analysis was performed for all time and frequency domain measures of HRV. 233 workers completed taking 24-hour ECG recordings. Results : This study shows that the 24 hourcircadian variation mainly follows work/sleep cycle rather than day/night cycle among shift workers. This study also shows that among the night shift, the circadian variation between work and sleep cycle decreased compared to the work/sleep cycle among day shift workers. All time and frequency domain parameters (except LF/HF ratio) show significantly different between work and sleep in the day shift and night shift. Conclusion : These changes in heart rate variability circadian rhythms reflect significant reductions in cardiac parasympathetic activity with the most marked reduction in normal vagal activity among the shift workers. Especially, it suggests the circadian rhytm has blunted among the night workers. The quantification of the circadian variation in HRV can be a surrogates of workers' potential health risk, as well as suggests possible mechanisms through which the shift works compromise workers' health.