• 대한의료기공학회지
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• 제10권1호
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• pp.130-157
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• 2007

The purpose of this research is to seek for efficient health maintenance device and to suggest desirable daily habit, based on the inquiry on interrelationship between workers' daily lives and their heartbeat change level. The paper survey about general features, case history and daily habits was conducted on workers during medical examination in Jeollabukdo, and examined their change of heartbeat as well. The results of research deducted from data analysis are as follows; 1. There found very positive interrelations between time-domain analysis and frequency-domain analysis, and MHR and LF/HF ratio had negative connection with other analyses. 2. The recipient showed high time-domain analysis when they are younger, have worked shorter or have spouse, and it contributes to stable sympathetic nerve and parasympathetic nerve as it stimulates autonomic nervous system. 3. According to the result of frequency-domain analysis, recipients showed higher TP and LF when they are younger, and the highest HF when they are under 34.The level of VLF was higher for university graduates than the ones who finished high school. The recipients showed higher TP and HF when they don't have spouse, and lower TP, LF and HF when they have worked longer. 4. The level of RMSSD and TSRD was high for the people who don't have case history, and HF was high when they don't have any disease in progress. 5. According to the result concerning correlation of daily habits with time-domain analysis and frequency-domain analysis, cigarette, alcohol and sleeping hours don't affect heartbeat change, but the ones who regularly workout showed higher result in every analysis. It shows that the autonomic nervous system of recipients who regularly exercise response more actively. The result mentioned above suggests that the change of heartbeat is a direct index which shows the change of autonomic nervous system, and it depends on the exercise the most. Thus, workout is proved to be the best method in order for workers to take care of their health.

• 전자공학회논문지SC
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• 제47권5호
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• pp.33-42
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• 2010

본 연구에서는 주기적인 심장 박동과 호흡으로 인해 발생하는 인체의 미세한 변위를 기반으로 심폐활동을 모니터링 하는 방법을 제안하였다. 제안한 시스템은 에어쿠션과 센싱 하드웨어 및 신호처리 알고리즘으로 구성되어 있다. 에어쿠션은 피부의 표면에 센서의 부착없이 무구속적으로 심박과 호흡을 측정하는데 사용되며 에어쿠션 위에 피험자가 앉았을 때 쿠션내부에 작은 압력변화를 일으킨다. 에어쿠션 내부의 미세한 압력변화는 압력센서에 의해 전기적인 신호로 변환되고 아날로그 하드웨어에 의해 증폭되고 필터링 되어 출력된다. 압력센서에서 발생한 신호는 주파수 영역필터에 의해 심박과 호흡으로 분리되어 추출된다. 에어쿠션의 계측 성능을 평가하기 위해 기존의 계측방법인 심전도와 호흡신호를 동시에 측정 후 비교하였다. 에어쿠션을 이용한 호흡 및 심박 검출률의 평균 민감도는 각각 98.67%, 99.24% 이다. 이 결과를 통해 에어쿠션을 이용한 심폐 활동 측정 방법은 설치 과정이 간단하고 쉬우며 일상생활에서 무구속적으로 호흡 및 심박을 모니터링 하는데 사용할 수 있음을 알 수 있었다.

• 한국항행학회논문지
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• 제13권4호
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• pp.482-489
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• 2009

이 논문에서는 AWGN환경에서 발생하는 가우시안 잡음과 발진기에서 생기는 시스템 잡음을 제거할 수 있는 ALE(Adaptive Line Enhancer) 기반의 새로운 적응형 잡음 제거기를 이용한 CW(Continuous-Wave) 바이오 레이더를 제안한다. 최근에 CW 바이오 레이더를 이용해서 심장박동과 호흡을 검출하는 연구가 여러 연구기관에서 진행 되고 있다. 그러나 이 연구들은 기존 CW 바이오 레이더가 가우시안 잡음에 취약하고 그로 인해 심장박동 검출정확도도 떨어진다는 점을 설명을 하고 있긴 하지만, 그 잡음을 효과적으로 없앨 수 있는 방안은 계속 연구 중에 있다. 본 논문에서는 기저대역 신호에 포함된 잡음을 효과적으로 제거할 수 있는 ALE기반의 적응형 잡음 제거기를 적용한 것을 제안한다. 또한 타겟의 위치에 따른 복조의 민감함에 강점을 가진 quadrature 수신기를 통과한 잡음이 포함된 기저대역 신호에서 잡음만을 효과적으로 제거함으로 인해 심장박동 검출 정확도를 향상시키는 것을 모의실험을 통해 비교 분석해 본다.

• 한국위성정보통신학회논문지
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• 제9권1호
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• pp.85-89
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• 2014

심전도(electrocardiography, ECG)는 심장박동을 할 때, 발생하는 탈분극과 재분극으로 심장의 전위변화를 시간의 흐름에 따라 파형으로 표현한 것이다. 의료기관에서는 심전도신호를 이용하여 환자의 심장질환을 진단한다. 일반적으로 사람의 정상적인 심장박동수는 1분에 60-100회 이다. 만약 정상적인 심장박동 수보다 느리거나 빠르다면 부정맥이라고 한다. 본 논문에서는 심전도신호에서 R-peak를 검출하여, R-R 간격을 구하고 부정맥 중에 서맥(bradycardia)과 빈맥(tachycardia) 구간을 검출하는 알고리즘을 제안하고 모의실험을 하였다.

• Journal of information and communication convergence engineering
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• 제11권3호
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• pp.216-222
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• 2013

It is known that blood circulation in human body causes the skin tone to change concurrently with heartbeats. A number of apps have been developed to measure the heartbeat using smartphone camera; however, no any further analysis is performed. In this paper we propose an algorithm that detects heartbeats from the phone's camera and further extracts the heart rate variability (HRV). We compare the HRV extracted from the camera with the HRV extracted from the electrocardiogram. We estimated a number of commonly used HRV characteristics and compared them. Our results show that smartphone camera leads to slightly overestimated characteristics although the difference in extracted HRV signals is negligible. As a consequence we suggest that a smartphone camera can be employed in a quick heart diagnosis and diagnosis of autonomic nervous system.

• Journal of Chest Surgery
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• 제16권2호
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• pp.199-212
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• 1983

The inhibition/influences of adenine compounds on the heart have been described repeatedly by many investigators, since the first report by Druny and Szent-Gyorgyi [1929]. These studies have shown that adenosine and adenine nucleotides have an over-all effect similar to that of acetylcholine [ACh] by slowing and weakening the heartbeat. The basic cellular and membrane events underlying the inhibitory action of adenosine on sinus rate, however, are not well understood. Furthermore, the physiological role of adenosine in regulation of the heartbeat remains still to be elucidated. Therefore, this study was undertaken in order to examine the response of rabbit SA node to adenosine and to compare the response to that of ACh. Isolated SA node preparation, whole atrial pair, or left atrlal strip was used in each experiment. Action potentials of SA node were recorded through the intracellular glass microelectrodes, which were filled with 3M KCI and had resistance of 30-50 M. All experiments were performed in a bicarbonate-buffered Tyrode solution which was aerated with 3% $CO_2-97%$ $O_2$ gas mixture and kept at $35^{\circ}C$. Spontaneous firing rate of SA node at 35C [Mean + SEM, n=16] was 154 + 3.3 beats/min. The parameters of action potentials were: maximum astolic potential [MDP], -731.7mV: overshoot [OS], 9 + 1.4mV; slope of pacemaker potential [SPP], 94 3.0mV/sec.Adenosine suppressed the firing rate of SA node in a dose dependent manner. This inhibitory effect appeared at the concentration of $10^{-6}M$ and was potentiated in parallel with the increase in adenosine concentration. Changes in action potential by adenosine were dose-dependent increase of MDP and decrease of SPP until $10^{-4}$. Above this concentration, however, the amplitude of action potential decreased markedly due to the simultaneous decrease of both MDP and OS. All these effects of adenosine were not affected by pretreatment of atropine [2mg/l] and propranolol [$5{\times}10^{-6}M$]. ACh [$10^{-6}M$] responses on action potential were similar to those of adenosine by increasing MDP and decreasing SPP. These effects of ACh disappeared by pretreatment of atropine [2mg/1]. Inhibition/effects of adenosine and ACh on sinus rate were enhanced synergistically with the simultaneous administration of adenosine and ACh. Marked decrease of overshoot potential was the most prominent feature on action potential. Dipyridamole [DPM], which is known to block the adenosine transport across cell membrane, definitely potentiated the action of adenosine . Adenosine suppressed the sinus rate and atrial contractility in the same dosage range, even in the reserpinized preparation. Above` results suggest that adenosine suppresses pacemaker activity, like ACh, by acting directly on the membrane of SA node, increasing MDP and decreasing SPP.

• 전기학회논문지
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• 제60권3호
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• pp.654-661
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• 2011

This paper is about a personal identification algorithm using an ECG that has been studied by a few researchers recently. Previously published algorithm can be classified as two methods. One is the method that analyzes of ECG features and the other is the morphological analysis of ECG. The main characteristic of proposed algorithm can be classified the method of analysis ECG features. Proposed algorithm adopts DSTW(Down Slope Trace Wave) for extracting ECG features, and applies SVM(Support Vector Machine) to training and testing as a classifier algorithm. We choose 18 ECG files from MIT-BIH Normal Sinus Rhythm Database for estimating of algorithm performance. The algorithm extracts 100 heartbeats from each ECG file, and use 40 heartbeats for training and 60 heartbeats for testing. The proposed algorithm shows clearly superior performance in all ECG data, amounting to 93.89% heartbeat recognition rate and 100% ECG recognition rate.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2017년도 춘계학술대회
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• pp.503-504
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• 2017

최근 세계 각국의 경제적 성장과 함께 건강한 삶에 대한 관심이 증가하고 있으며, 이에 따른 스마트헬스케어 산업이 활성화 되고 있다. 스마트헬스케어 분야에서는 IoT기술의 부각에 따라 웨어러블 형태의 생체정보 계측기술이 부각되고 있다. 본 연구에서는 웨어러블 헬스케어에 응용이 가능하고 활동 중에도 편리하게 심박동의 모니터링을 수행 할 수 있는 장갑형태의 착용형 심박동 모니터링시스템을 구현하고자 하였다. 이를 위해 손가락 말초에서의 혈류량변화를 모니터링하고 디스플레이 할 수 있는 장갑형 웨어러블 헬스케어시스템을 제작하고 그 성능평가를 수행하였다. 실험결과 실제 일상생활 중 움직임을 수반하더라도 심박동의 모니터링이 가능함을 확인할 수 있었다.

• 한국산업보건학회지
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• 제16권2호
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• pp.183-192
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• 2006

Predicting energy expenditure (EE) is important to prevent work-related musculoskeletal disorders (WMSDs). The problem to predict EE is that the standard of EE is based on western data. The authors checked average EE by job categories to provide basic data for suggesting proper work intensity for Korean workers. This study was conducted from 2003 to 2005. Study subjects were recruited from 4 car parts assembly plant, 2 car assembly plant, 2 Heavy machine manufacturing plant and 2 shipyards. Total study subjects were 515 male workers. To estimate VO2max, sub-maximal test was conducted to measure VO275%max by bicycle ergometer (Combi Co, Aerobike 75XL II). Heartbeats were recorded with heartbeat recorder (Polar Electro Co, Finland, S810) during work. EE of work was calculated by recorded heartbeat and individual regression equation which was derived from sub-maximal test. Subjects were classified into 4 industry and 8 work posture, 23 job task categories. Mean EEs (S.D.) according to industry classification (kcal/min) were 4.9 (0.7), 4.8 (0.7), 4.9 (0.7), 5.0 (0.9), and 4.0 (0.5) for Car Part manufacture, Car Assembly, Ship Building, Heavy Machinery Manufacture, and Hospital Office, respectively. The results suggest that Korean male workers of exceeding to the NIOSH criteria will be needed to plan for job rescheduling to maintain $worker^{\circ}$Øs health. Further study to establish Korean work intensity standard would be needed.

• 융합신호처리학회논문지
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• 제20권1호
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• pp.45-50
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• 2019

모바일 헬스케어 디바이스에서 가장 많이 사용되는 PPG 신호는 디바이스 사용자의 움직임의 영향에 따라 심박수 측정의 정확도가 떨어진다. 그 이유는 사용자의 동잡음의 주파수 대역이 PPG 신호의 주파수 대역과 겹쳐 있기 때문이다. 이러한 동잡음을 제거하기 위해 주파수 분석법, 가속도 센서 적용 등의 다양한 방법들이 연구되어 우수한 성능을 제시하였지만, 저가의 헬스케어 디바이스에 이들 필터법을 적용함에 있어 많은 연산처리 시간과 센서 가격 측면 때문에 적용하기가 어렵다. 이러한 문제점을 해결하기 위해 본 연구에서는 실시간으로 보다 정확한 심박수를 추출하기 위해 퍼지추론 시스템과 적응노치 필터를 이용한 PPG 신호처리 기법을 제안하고 그 성능을 평가하였다. 그 결과, 기존의 방법보다 우수한 결과를 보였으며, 이 결과를 토대로 제안된 방법을 모바일 헬스케어 디바이스 설계에 적용한다면 실시간으로 보다 정확한 심박수 측정이 가능할 것이다.