• 대한의용생체공학회:의공학회지
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• 제28권4호
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• pp.441-448
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• 2007

Heart rate variability (HRV) in electrocardiogram (ECG) is an important index for understanding the health status of heart and the autonomic nervous system. Most HRV analysis approaches are based on the proper heart rate (HR) data. Estimation of heart rate is thus a key process in the HRV study. In this paper, we report an innovative method to estimate the heart rate. This method is mainly based on the concept of periodicity transform (PT) and instantaneous period (IP) estimate. The method presented is accordingly called the "PT-IP method." It does not require ECG R-wave detection and thus possesses robust noise-immune capability. While the noise contamination, ECG time-varying morphology, and subjects' physiological variations make the R-wave detection a difficult task, this method can help us effectively estimate HR for medical research and clinical diagnosis. The results of estimating HR from empirical ECG data verify the efficacy and reliability of the proposed method.

• The Korean Journal of Physiology
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• 제5권2호
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• pp.15-27
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• 1971

Physiological analysis of the physical exercise was made on 9 subjects performing mountain climbing. The course between two points (256 and 516 meters altitude) was 1,300 meters in distance and difference of vertical height was 260 meters making the mean grade of 20%. In the field, the heart rates during uphill or downhill walk were recorded by EKG radio-telemetry. In the laboratory, oxygen consumption was obtained by the recorded heart rates, using individual heart rate vs oxygen consumption diagram obtained by treadmill test. the following results were obtained. 1. Uphill walk time was 36.5 minutes, and during this period the mean heart rate was 149.0 heats/min and peak heart rate was 169.2 beats/min. The total heart beats during the uphill walk was 5.433 beats. 2. The ratio of individual mean heart rate during the uphill walk to the maximal heart rate distributed between 66.6% and 98.3%, and the mean of the total group was 83.1%. The ratio of peak heart rate of uphill walk to the maximal heart rate was 94.5% in the group. Thus uphill walk of a 20% grade mountain course was an exhaustive exercise. 3. Oxygen consumption during uphill walk was 2.22 l/min (ranged between 1.79 and 2.70 l/min) and the ratio of this to the resting oxygen consumption was 8.31. The peak value of oxygen consumption during uphill walk was 2.73 l/min and the ratio of this to the resting oxygen consumption was 10.39. 4. Energy expenditure during uphill walk showed a mean of 11.1 kcal/min and the peak expenditure rate was 13.6 kcal/min. The total energy expenditure during 36.5 minutes of uphill walk was 396 kcal. 5. In downhill walk, the time was 31.7 minutes, mean heart rate was 118.4 (ranged between 100.1 and 142.7) beats/min, and the peak heart rate was only 129.4 beats/min. The ratio of mean heart rate to the maximal heart rate was 66.3%. Total heart beats during downhill walk was 3,710 beats. The ratio of downhill oxygen consumption to the resting consumption was 5.70. The rate of energy expenditure was 7.5 kcal/min, and the total onery expenditure during the 31.7 minutes of downhill walk was 228 kcal. 6. The effect of training was manifest in the uphill walk and not in the downhill walk. After training in mountain course walk, i) the uphill time was shortened, ii) mean heart rate increased, iii) time vs heart rate curve became smooth and showed less frequent zig-zag, i.e., the depth of trough on the curve decreased and the magnitude was less than 10 beats. In non-trained subject the depth of trough on the curve was greater than 50 beats and appeared more frequently. 7. Mountain climbing is a good health promotion exercise. For the promotion of health the reasonable amount of uphill mountain walk exercise in a 20% grade course is a walk for 40 or 50 minutes duration once a week.

• 한국HCI학회:학술대회논문집
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• 한국HCI학회 2008년도 학술대회 1부
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• pp.158-162
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• 2008

심박은 주위에 환경적, 신체적, 정신적 상태가 많은 영향을 끼친다. 실험에서 정서를 판단함에 있어서 안정된 상태를 만들어야 정확한 데이타를 얻을 수 있다. 사람은 하루 중 심박수가 시간 및 상태에 따라서 다르다. 그래서 심박수의 안정 상태를 만들어야 한다. 의학에서는 신체적으로 볼 때 낮아지는 심박수일수록 안정 상태이다. 하지안 사람마다 평균 심박수가 다르고 시간마다 심박수 평균이 달라진다. 그래서 심박수로는 안정 심박을 구하기가 힘들다. 심박 패턴을 추출할 때 장기 분석을 통한 검증이 정확하다. 하지만 장기 분석을 하지 않아도 피험자의 안정 상태를 유도 할 수 있다면 장기 분석을 하지 않아도 된다. 안정 심박 패턴을 유도하기 위해서 사용한 청각자극은 우리가 일반적으로 집중력과 스트레스 피로를 해소하는 MC Square와 모차르트 음악을 선정하였다. 두 개의 청각 자극이 안정된 심박을 유도 와 안정된 심박 패턴을 만들 수 있는지를 분석하여 유사점과 차이점을 비교하였다. 본 논문은 분당 심박수 변화와 심박 패턴분석으로 청각자극이 안정된 심박수를 유도하는 유의미한 결과 얻었으며 주위의 영향을 받지 않는 상태 즉, 평상심을 유도 할 수 있었다.

• 한국정보전자통신기술학회논문지
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• 제3권1호
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• pp.13-18
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• 2010

본 연구에서는 ECG를 통하여 심박수를 R-R 간격을 이용한 방법으로 자동 추출하는 방법에 관하여 연구하였다. 육안으로 측정한 심박수를 기준으로, 2차 미분을 이용하여 심박수를 추출하는 방법, 자기상관함수를 이용하여 심박수를 추출하는 방법을 비교하여 고찰하였다. 실험 데이터는 MIT/BIH database를 이용하였다. 이를 바탕으로 직접 ECG 측정기를 제작하여 심박수를 자동 측정하여 보고 기존의 환자감시장치(ICU)와 비교하여 보았다.

• 한국정보전자통신기술학회논문지
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• 제7권1호
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• pp.50-54
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• 2014

본 연구에서는 혈압측정으로부터 얻어지는 오실레이션(Oscillation) 신호를 이용하여 심박주기를 검출하고, 심박주기의 정확성을 개선하는 알고리듬을 개발하였다. 이를 위한 혈압측정의 방법으로 오실로메트릭(Oscillometric) 측정법을 사용하였으며, 오실레이션 신호의 피크들로부터 전 후 기울기들의 평균이 교차하는 지점을 실제 피크로 인정하고 심박주기를 계산하였다. 제안된 방법은 그래프 상에서 심박주기의 극심한 편차와 오류를 줄이는 성능을 나타냈다.

• 국제학술발표논문집
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• The 8th International Conference on Construction Engineering and Project Management
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• pp.257-264
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• 2020

Objective: To investigate test-retest reliability and responsiveness of Equivital Lifemonitor and photoplethysmography based wristwatch tools in assessing physiological parameters during a simulated fatigue task. Methods: Ten university students (Mean age, 30.6 ± 1.7 years) participated in this pilot study. Participants were asked to perform a 30-minute of a simulated fatigue task in an experimental setup in a lab. The physiological parameters (e.g., heart rate, heart rate variability, respiratory rate, electrodermal activity, and skin temperature) were measured at baseline and immediately after the fatigue task. An intraclass correlation coefficient (ICC2,1) was used to evaluate the test-retest reliability of each tool in assessing physiological measures. In addition, the responsiveness of each tool to measure changes from baseline to posttest was calculated using a standardized response mean. Results: The Equivital Lifemonitor has shown good to excellent test-retest reliability for the assessment of heart rate (ICC, 0.97), heart rate variability (ICC, 0.86), respiratory rate (ICC, 0.77), and local skin temperature (ICC, 0.76). However, photoplethysmography based wristwatch showed moderate to good test-retest reliability for the assessment of heart rate (ICC, 0.71), heart rate variability (ICC, 0.73), electrodermal activity (ICC, 0.80), and skin temperature (ICC, 0.72). A large standardized response mean (>0.8) indicates that both tools can capture the changes in heart rate, heart rate variability, respiratory rate, skin temperature, and electrodermal activity after a 30-minute of fatigue task. Conclusions: The Equivital Lifemonitor and photoplethysmography based wristwatch devices are reliable in measuring physiological parameters after the fatigue task. Additionally, both devices can capture the fatigue response after a simulated construction task. Future field studies with a larger sample should investigate the sensitivity and validity of these tools in measuring physiological parameters for fatigue assessment at construction sites.

• 정보처리학회논문지:컴퓨터 및 통신 시스템
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• 제4권8호
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• pp.253-258
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• 2015

u-헬스케어 관점에서 볼 때, 심박수(heart rate)는 아픈 사람의 질환을 관리하는 일리스(illness)나 건강한 사람의 건강을 지속적으로 관리하는 웰니스(wellness) 분야에 모두 유용하게 사용된다. 이는 심박수가 질환의 증상을 판단하거나 운동 부하의 지표로서 모두 사용될 수 있기 때문이다. 최근에 착용형 센서(wearable sensors)를 이용하여 상시적으로 심박수를 모니터링하여 이에 기반하여 현재 몸 상태를 점검해볼 수 있는 다양한 심박계(heart rate monitor)와 이와 연동하여 심박수를 이용한 다양한 운동관리 스마트폰 앱이 개발되어 출시되고 있다. 그러나 이러한 스마트폰 앱은 모두 개인 용도로 제한된다. 논문에서는 여러 사람들의 심박수를 동시에 실시간으로 모니터링할 수 있는 시스템을 설계하고, 이를 적용할 수 있는 안드로이드 앱을 개발한다. 개발된 앱의 주요 기능은 다수 이용자에 대한 동시적 심박수 모니터링으로 피트니스 센터에 효과적으로 적용 가능하다.

• 대한임베디드공학회논문지
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• 제14권3호
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• pp.123-131
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• 2019

In recent years, a non-contact respiration and heart rates monitoring via IR-UWB radar has been paid much attention to in various applications - patient monitoring, occupancy detection, survivor exploring in disaster area, etc. In this paper, we address a novel approach of real time heart rate estimation using IR-UWB radar. We apply sine fitting and peak detection method for estimating respiration rate and heart rate, respectively. We also deploy two techniques to mitigate the error caused by wrong estimation of respiration rate: a moving average filter and finding the frequency of the highest occurrence. Experimental results show that the algorithm can estimate heart rate in real time when respiration rate is presumed to be estimated accurately.

• PNF and Movement
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• 제16권2호
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• pp.161-168
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• 2018

Purpose: This study aimed to investigate the effects of postural control exercise on the delayed heart rate increase in heart transplant patients. Methods: The subject was a female heart transplant recipient who had a delayed increase in heart rate during exercise. The intensity of exercise was performed at MBorg level 4. The A-B-A' and A-B-A'-B' designs were used to identify the changes in heart rate during active-assisted exercise, lower limb postural control exercise, and upper limb postural control exercise. Experiments were performed for four weeks. The heart rates at pre- and post-exercise were compared, and the time to reach MBorg 4 was measured. Results: In the active-assisted exercise, the average heart rates at pre- and post-exercise and after 10 min of exercise were 88, 89, and 87.7 bpm, respectively. In the repetitive comparison of pre- and post-exercise in the lower limb postural control exercise, the difference in the mean heart rate was 3.5 and 3 bpm in stable support and 14 and 14.5 bpm in unstable support, respectively. In the repetitive comparison of pre- and post-exercise in the upper limb postural control exercise, the difference in the mean heart rate was 6 and 4 bpm in stable support and 4 and 4.5 bpm in unstable support. The time required to reach MBorg 4 was short when both the upper and lower postural control exercises were performed in an unstable state. Conclusion: We suggest that combining proper postural control exercise with strength exercise and aerobic exercise, among others, may be effective in rehabilitating patients in the recovery stage after a heart transplant.

• Journal of information and communication convergence engineering
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• 제8권1호
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• pp.112-115
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• 2010

The heart rate is the most important vital sign in diagnosing heart status. The simple method to measure the heart rate in the mobile healthcare device is using the PPG signal. In developing the mobile healthcare device using the PPG signal, the most important issue is the inaccuracy of the measured heart rate because the PPG signal is distorted from the user's motions. To improve the problem, this study proposed the new method that is to estimate the heart rate without an additional sensor in real life. The proposed method in this study is using the histogram filter. In order to evaluate the performance of the proposed method, the study compares its results with the moving average method in motion environment. According to the experimental results, the performance of the proposed method was more than 40% better than the performances of the MAF.