• Journal of Electrical Engineering and Technology
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• 제8권2호
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• pp.376-384
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• 2013

With the continuous aging of the populations in developed countries, the medical requirements of the aged are expected to increase. In this paper, a ring-type pulse oximeter finger sensor and a 24-hour ambulatory heart rate monitoring system for the aged are presented. We also demonstrate the feasibility of extracting accurate heart rate variability measurements from photoelectric plethysmography signals gathered using a ring-type pulse oximeter sensor attached to the finger. We designed the heart rate sensor using a CPU with built-in ZigBee stack for simplicity and low power consumption. We also analyzed the various distorted signals caused by motion artifacts using a FFT, and designed an algorithm using a least squares estimator to calibrate the signals for better accuracy.

• 전기학회논문지
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• 제57권6호
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• pp.1109-1115
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• 2008

In the ubiquitous health monitoring environments, it is quite important not only to evaluate the physiological health condition but also mental stress condition. In order to achieve this goal, a heart activity monitoring system utilizing a wearable bipolar electrode is devised and the heart rate variability(HRV) is extracted and interpreted in both frequency and time feature domains. Consequently, to evaluate the emotional stress condition of the subjects, a stress-induced experimental protocol was applied to healthy subjects and the time and frequency features of heart activity were analyzed in terms of the ratio of low frequency components v.s., high frequency components and the relevant the moving average distributions compromising the successive RR peaks intervals in the ambulatory ECG measurement system.

• 대한의용생체공학회:의공학회지
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• 제12권4호
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• pp.235-242
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• 1991

This research has reported that the selection and assessment of treatment in anxiety disorders depend to a large extend on patient reports of somatic symptomatology. However, the correspondence between such reports and actual physiological data Is unknown as the physiological measures used were taken in laboratory. The purpose of the ambulatory momboring device is, therefore, to present for analysis physiological data derived from the sub jects during their daily activities. The physiological parameters of interest are heart rate, respiratory rate, skin conductance level/response, skin temperature, and activity level. This device had an microcomputer based data acquisition unit, Interfaced to it for the purpose of data collection. The data is collected usually over a period of 12 hours. The data from the ambulatory monitoring device can be used to assess the psychophysiology of anxiety in the field. The data from the device will also reveal if patients who report different sets of symptoms differ physiologically too. Thls will help physicians for the right kind of treatment and also solve the many uncertainties that have existed thus far in quantizing anxiety.

• Journal of Yeungnam Medical Science
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• 제6권1호
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• pp.99-107
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• 1989

저자들은 1987년 9월부터 1989년 4월사이 약 19개월간 영남대학병원 내과에 입원하여 만성 심방세동 진단하에 치료받고 있던 환자 34명을 대상으로 digoxin치료를 받은 20명과 치료를 받지 않은 10명에 대한 24시간 ambulatory ECG를 시행하여 두 집단간의 심박수의 변화 및 가장 긴 정지기등을 비교 분석한 결과 다음과 같은 성적을 얻었다. 1) 대상환자 34례의 평균 심박수의 평균치는 $75.7{\pm}13.8$회/min.($mean{\pm}S.D.$), 가장 빠른 심박수는 $148.0{\pm}32.4$/min.($mean{\pm}S.D.$), 가장 느린 심박수는 $48.1{\pm}8.4$회/min.($mean{\pm}S.D.$)이었고 가장 빠른 심박수와 가장 느린 심박수의 차이의 평균치는 $99.9{\pm}29.0$회/min.($mean{\pm}S.D.$), 가장 긴 정지기는 $2.95{\pm}1.06sec.$($mean{\pm}S.D.$)이었으며 이중 4명은 가장 긴 정지기가 4.0sec.이상으로 sick sinus syndrome을 배제할 수 없어서 비교대상집단에서는 제외시켰다. 2) 대상환자 34례중 27례에서 심실성 기외수축이 있었으며 100회/24hours이내가 11례(40.7%)로 가장 많았고, 변성전도(aberrant conduction)는 전례에서 다 나타났다. 3) Digoxin(0.25mg/day)으로 치료받은 20례의 평균 심박수의 평균치는 $78.4{\pm}13.7$회/min.($mean{\pm}S.D.$), 가장 빠른 심박수는 $152.5{\pm}33.1$회/min.($mean{\pm}S.D.$), 가장 느린 심박수는 $48.9{\pm}8.5$회/min.($mean{\pm}S.D.$) 이었고 가장 빠른 심박수와 가장 느린 심박수의 평균치는 $103.6{\pm}31.7$회/min.($mean{\pm}S.D.$), 가장 긴 정지기는 $2.55{\pm}0.50$sec.($mean{\pm}S.D.$)이었다. 4) Digoxin으로 치료받지 않은 10례의 평균 심박수의 평균치는 $78.0{\pm}10.7$회/min.($mean{\pm}S.D.$), 가장 빠른 심박수는 $154.5{\pm}26.8$회/min($mean{\pm}S.D.$), 가장 느린 심박수는 $50.6{\pm}7.1$회/min.($mean{\pm}S.D.$)이었고 가장 빠른 심박수와 가장 느린 심박수의 평균치는 $103.9{\pm}22.2$회/min.($mean{\pm}S.D.$), 가장 긴 정지기는 $2.66{\pm}0.39sec.$($mean{\pm}S.D.$)이었다. 5) Digoxin으로 치료받은 20명과 치료받지 않은 10명의 두 집단간의 평균 심박수, 가장 빠른 심박수, 가장 느린 심박수, 가장 빠른 심박수와 가장 느린 심박수의 차이, 가장 긴 정지기의 차이는 통계학적으로 유의하지 않았다(P>0.05). 이상을 요약하면 하루 0.25mg의 digoxin투여로 만성 심방세동 환자의 심박수는 잘 조절되었으며 만성 심방세동 환자의 치료유무 결정 및 치료약제에 대한 반응등을 평가하는데 ambulatory ECG가 유용하고 안전한 검사법으로 사료된다.

• Safety and Health at Work
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• 제6권3호
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• pp.192-199
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• 2015

Background: Overweight, obesity, and cardiovascular disease risk factors are prevalent among firefighters in some developed countries. It is unclear whether physical activity and cardiopulmonary fitness reduce cardiovascular disease risk and the cardiovascular workload at work in firefighters. The present study investigated the relationship between leisure-time physical activity, cardiopulmonary fitness, cardiovascular disease risk factors, and cardiovascular workload at work in firefighters in Hong Kong. Methods: Male firefighters (n = 387) were randomly selected from serving firefighters in Hong Kong (n = 5,370) for the assessment of cardiovascular disease risk factors (obesity, hypertension, diabetes mellitus, dyslipidemia, smoking, known cardiovascular diseases). One-third (Target Group) were randomly selected for the assessment of off-duty leisure-time physical activity using the short version of the International Physical Activity Questionnaire. Maximal oxygen uptake was assessed, as well as cardiovascular workload using heart rate monitoring for each firefighter for four "normal" 24-hour working shifts and during real-situation simulated scenarios. Results: Overall, 33.9% of the firefighters had at least two cardiovascular disease risk factors. In the Target Group, firefighters who had higher leisure-time physical activity had a lower resting heart rate and a lower average working heart rate, and spent a smaller proportion of time working at a moderate-intensity cardiovascular workload. Firefighters who had moderate aerobic fitness and high leisure-time physical activity had a lower peak working heart rate during the mountain rescue scenario compared with firefighters who had low leisure-time physical activities. Conclusion: Leisure-time physical activity conferred significant benefits during job tasks of moderate cardiovascular workload in firefighters in Hong Kong.

• Healthcare Informatics Research
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• 제24권4호
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• pp.283-291
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• 2018

Objectives: To identify the current status of smartphone usage and to describe the needs for smartphone-based cardiac telerehabilitation of cardiac patients. Methods: In 2016, a questionnaire survey was conducted in a supervised ambulatory cardiac rehabilitation (CR) program in a university affiliated hospital with the participation of heart failure or heart transplantation patients who were smartphone users. The questionnaire included questions regarding smartphone usage, demands for smartphone-based disease education, and home health monitoring systems. Results were described and analyzed according to principal diagnosis. Results: Ninety-six patients (66% male; mean age, $5{\pm}11$ years), including 56 heart failure and 40 heart transplantation patients, completed the survey (completion rate, 95%). The median daily smartphone usage time was 120 minutes (interquartile range, 60-300), and the most frequently used smartphone function was text messaging (61.5%). Of the patients, 26% stated that they searched for health-related information using their smartphones more than 1 time per week. The major source of health-related information was Internet browsing (50.0%), and the least sought source was the hospital's website (3.1%). Patients with heart failure expressed significantly higher needs for disease education on treatment plan, home health monitoring of blood pressure, and body weight (${\chi}^2=5.79$, 6.27, 4.50, p < 0.05). Heart transplantation patients expressed a significant need for home health monitoring of body temperature (${\chi}^2=5.25$, p < 0.05). Conclusions: Heart failure and heart transplantation patients show high usage of and interest in mobile health technology. A smartphone-based cardiac telerehabilitation program should be developed based on high demand areas and modified to suit to each principal diagnosis.

• 한국직업건강간호학회지
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• 제18권1호
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• pp.14-21
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• 2009

Purpose: This study was performed to investigate the effect of shift work on diurnal blood pressure (BP) pattern in nurses. Method: We studied 20 healthy nurses engaged in 3 shift work. 24-hour ambulatory BP monitoring was performed to each nurse two times during the day and night shift. Five nurses were excluded because of inadequate BP measurement. Results: All subjects were female. The mean age was 27.4 years (range: 23-33 years) and mean body mass index was 19.7 Kg/$m^2$ (range: 18.0-21.2 Kg/$m^2$). The changes of systolic BP ($17.8{\pm}9.1$ vs. $13.2{\pm}4.7%$, p=0.031), diastolic BP ($22.3{\pm}8.7$ vs. $17.3{\pm}9.0%$, p=0.061), and heart rate ($25.2{\pm}5.2$ vs. $12.5{\pm}8.7%$, p=0.001) during the sleeping period were decreased after a night shift compared with day shift. The non-dipper group significantly increased from 20% to 40% after a night shift (p=0.018). Conclusion: Working night shift is significantly associated with non-dipper status in nurses.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.328-330
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• 2004

In this paper, ECG based cardiac disease diagnosis models are developed. Conventionally, ECG monitoring equipments can only measure and store ECG signals and they always require medical doctor's diagnosis actions which are not desirable for continuous ambulatory monitoring and diagnosis healthcare systems. In this paper, two kinds of neural based self cardiac disease diagnosis engines are developed and tested for four kinds of diseases, sinus bradycardia, sinus tachycardia, left bundle branch block and right bundle branch block. For diagnosis engines, error backpropagation neural network (BP) and probabilistic neural network (PNN) were applied. Five signal features including heart rate, QRS interval, PR interval, QT interval, and T wave types were selected for diagnosis characteristics. To show the validity of proposed diagnosis engine, MIT-BIH database were used to test. Test results showed that BP based diagnosis engine has 71% of diagnosis accuracy which is superior to accuracy of PNN based diagnosis engine. However, PNN based diagnosis engine showed superior diagnosis accuracy for complex-disease diagnoses than BP based diagnosis engine.

• 대한한방내과학회지
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• 제20권1호
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• pp.222-231
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• 1999

Uwhangchungsimwon(UC) has been used in the treatment of a wide variety of conditions including stroke, hypertension, arteriosclerosis, autonomic imbalance, mental instablity, etc in Korean traditional hospitals, In particular it is often initialy chosen for emergency care of acute stroke. The aim of this study was to evaluate the effect of UC on cerebral hemodynamics. Using transcranial Doppler ultrasound, we studied changes of mean flow velocity and pulsatility index(PI) of middle cerebral arteries (MCAs) from 11 health young volunteers who were administrated with 1 pill UC and 11 health controls who were not. We obtained hypercapnia with breath-holding and evaluated cerebrovascular reactivity with breath-holding index(BHI). Systolic blood pressure, diastolic blood pressure, and heart rate were measured using ambulatory blood pressure monitoring(ABPM). In UC administration group, the evaluation was performed during basal condition. and repeated at 20, 40, and 60 min after administration. In controls, the evaluation was performed at corresponding time intervals. Mean flow velocity in middle cerebral artery, systolic blood pressure, diastolic blood pressure, and heart rate did not change during the observation period and were not different between these two groups. However, administration of UC was associated with decreases in PI by $3.6{\sim}12.4%$ in BHI by $17.9{\sim}24.8%$ compared with pre-administration period. Decreases in PI and BHI with UC were significantly different compared with control group (p<0.05). These results indicate that UC decreases PI and BHI in cerebral artery, which is due to a dilation of cerebral resistance vessels.

• 한국산학기술학회논문지
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• 제13권12호
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• pp.5849-5859
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• 2012

본 연구는 고혈압노인과 정상혈압노인 그리고 청년 간의 식후혈압 변화 양상의 차이를 파악하기 위하여 참여자들의 서면동의를 받아 조사하였다. 휴대용 혈압모니터(ABPM)를 사용하여 식전 30분부터 식후 90분까지 15분 간격으로 혈압을 측정하였다. 고혈압노인군(26명)은 수축기혈압이 식후 30분부터 식후 90분까지 지속적으로 하강하였고, 최대 $19.3{\pm}19.4mmHg$ 하강하여, 정상혈압노인군(25명: $-7.7{\pm}9.4mmHg$) 및 청년군(26명: $-1.3{\pm}4.1mmHg$)과 차이가 있었다. 고혈압노인군의 식후 이완기혈압은 최대 $25.0{\pm}15.1mmHg$ 하강하였고 정상혈압노인군($-6.1{\pm}6.0mmHg$)과 청년군($-5.7{\pm}5.0mmHg$) 과 차이가 있었다. 고혈압노인군과 정상혈압노인군에서는 맥박수의 변화가 없었고, 청년군에서는 식후 30분에 일시적으로 맥박수가 상승하였다(p=.014). PPH 발생률은 고혈압노인군 73.1%, 정상혈압노인 24% 이었고, 청년군은 PPH 발생자가 없었다(p=.001). 따라서 간호사는 고혈압노인의 식후저혈압을 확인하기 위한 식후혈압 측정을 실시해야 한다. 또한 식후 90분까지는 갑작스런 혈압하강과 관련된 합병증의 발생을 주의관찰하고 관리하도록 하여야 한다.