• Journal of Korea Society of Industrial Information Systems
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• v.19 no.1
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• pp.43-52
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• 2014

P-wave characteristic in the human electrocardiogram (ECG) is important in the diagnosis of atrial conduction pathology. In this paper, we measured an ECG signal from patient with cardiovascular disease using one lead ECG electrode system which is based on the wireless cardiac monitoring system. And we detected a P-wave in ECG signal using the complex-valued continuous wavelet transforms (CWT) according to two kinds of patch type electrodes such as an existing narrow patch type electrode and the improved wide patch type electrode presented in this paper. Also, we compared the characteristics in detecting the P-wave in terms of the magnitude and the width of P-waves. From the results of comparison we found that the width and the magnitude of P-wave detected using the wide patch type electrode is improved to be interpreted easier compared to those using the narrow patch type electrode. Furthermore, we have also proven that the complex-valued CWT can be used as a robust detector for P-wave in ECG signal analysis.

• Journal of Chest Surgery
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• v.57 no.2
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• pp.205-212
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• 2024

Background: Postoperative atrial fibrillation (A-fib) is a serious complication of cardiac surgery that is associated with increased mortality and morbidity. Traditional 24-hour Holter monitors have limitations, which have prompted the development of innovative wearable electrocardiogram (ECG) monitoring devices. This study assessed a patch-type wearable ECG device (MobiCARE-MC100) for monitoring A-fib in patients undergoing cardiac surgery and compared it with 24-hour Holter ECG monitoring. Methods: This was a single-center, prospective, investigator-initiated cohort study that included 39 patients who underwent cardiac surgery between July 2021 and June 2022. Patients underwent simultaneous monitoring with both conventional Holter and patchtype ECG devices for 24 hours. The Holter device was then removed, and patch-type monitoring continued for an additional 48 hours, to determine whether extended monitoring provided benefits in the detection of A-fib. Results: This 72-hour ECG monitoring study included 39 patients, with an average age of 62.2 years, comprising 29 men (74.4%) and 10 women (25.6%). In the initial 24 hours, both monitoring techniques identified the same number of paroxysmal A-fib in 7 out of 39 patients. After 24 hours of monitoring, during the additional 48-hour assessment using the patch-type ECG device, an increase in A-fib burden (9%→38%) was observed in 1 patient. Most patients reported no significant discomfort while using the MobiCARE device. Conclusion: In patients who underwent cardiac surgery, the mobiCARE device demonstrated diagnostic accuracy comparable to that of the conventional Holter monitoring system.

• Journal of Biomedical Engineering Research
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• v.35 no.6
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• pp.203-210
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• 2014

Wearable medical device has been a resurgence of interest thanks to the development of technology and propagation of smart phone in recent years. Various types of wearable devices have been introduced and available in market. Capacitive coupled electrode which measures electrocardiogram over cloth is able to be applied wearable device. In previous approaches of capacitive electrode, they need proper pressure for stable contact of the electrode to body surface. However, wearable device that gives pressure on body surface is not suitable for long-term monitoring. In this study, we proposed adhesive polyurethane-based capacitive electrode for patch-type wearable electrocardiogram (ECG) monitoring device. Self-adhesive polyurethane make the electrode and whole system be adhered to the surface of skin without any pressure. The patch-type system is consisted of analog filter, analog-to-digital converter and wireless transmission module and designed to be attached on the body as a patch. To validate the feasibility of the developed system, we measured ECG signal in stable and active state and extracted heart rate. Therefore, we observed skin response after long-term attachment for biocompatibility of the adhesive polyurethane and adhesive strength of it. The result shows the possibility of applying the developed system for ECG monitoring in real-life.

• Science of Emotion and Sensibility
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• v.12 no.2
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• pp.161-168
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• 2009

In this study, we have developed the patch type HAMS (Heart Activity Monitoring System) which is non-restricted, non-awarable and non-invasive. The module using wireless telecommunication to receive the ECG (electrocardiogram) signal at the computer has mobility which it easily monitors the heart activity of subjects in no time for long term at any time and places. We developed the small patch type electrode which can be attached on the chest. Also the reliability and moving artifact of ECG signal measured by this electrode have been verified. Using HAMS, we measured the HRV (Heart Rate Variability) parameters, the questionnaire evaluation for anxiety and stress and the amount of stress hormone (cotisol) to evaluate the stress effect in HRV on the same subject. As a result of comparing the values under non stressed and stressed condition, there was significant difference on many parameters. And the parameter highly related with stress on Pearson's Correlation Coefficient has been examined. These show that using HAMS is able to evaluate the function of autonomic nervous system. Therefore, we can predict heart problem in daily life by using HAMS. Also we expect that this module can be applied for more application as health monitoring system.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.6
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• pp.1102-1108
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• 2008

Wearable physiological signal monitoring systems are regarded as an important sensing unit platforms in ubiquitous/mobile healthcare application. In this paper, we suggested the modified bipolar electrodes implemented on the portable heart activity monitoring system, which minimized the distance of electrodes formed on a attachable pad. The proposed electrode configuration is useful in mobile measurement environments, but has a disadvantage of reduced amplitude of the heart action potential. In order to overcome the shortcoming of the suggested electrode configuration, we implemented the amplifying circuit to increase the signal-gain and decrease the artifacts. For evaluations, we analyzed the specificity of measured cardiography using the proposed electrodes through the comparing of heart activity monitoring system with standard clinical ECG(lead2) by pearson correlation coefficients. The result showed that the average correlation coefficient is $0.903{\pm}0.036,\;0.873{\pm}0.072$ at V3, V4 chest lead position, respectively. Thus, the modified bipolar electrode is quite suitable to monitor the electrical activity of the heart in the situation of the mobile environment, and could be considered having high similarity with standard clinical ECG.

• Journal of IKEEE
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• v.22 no.4
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• pp.953-958
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• 2018

In this study, a portable detection system was developed that can detect harmful gas and signals simultaneously in an enclosed space of industrial sites and underground facilities. The developed system is a sensor module for gas detection, a patch type 1 channel small ECG sensor, a module for three-axial acceleration detection sensor, and a system for statistics. In order to verify the performance of the system modules, the digital resolution, signal frequency, output voltage, and ultra-small modules were evaluated. As a result of the performance of the developed system, the digital resolution was 300 (rps) and the signal amplification gain was 500 dB or more, and the ECG module was manufactured with $50mm{\times}10mm{\times}10mm$ to increase patch utilization. It is believed that the product of this research will be valuable if it is used as an IoT-based management system for real-time monitoring of industrial workers.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.8
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• pp.2008-2016
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• 2014

With the increased attention about health care and management of heart diseases, ubiquitous healthcare services and related devices have been actively developed recently. In this paper we developed a mobile healthcare system which consists of smartphone and patch-type ECG measuring device. This system is capable of monitoring, storing, and sending bio signals such as ECG, heart rate, heart rate variability as well as exercise management functions through heart rate zones. With monitoring bio signal continuously by mobile healthcare system and wearable device like us, people can prevent chronic disease and maintain good health. Here we report our implementation results on real platforms.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2009.05a
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• pp.173-176
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• 2009

심박동 변동에 반영되는 자율신경계 활동으로부터 정신적 부하 즉 스트레스 상태를 평가할 수 있다. 또한 일상생활 중에서 지속적인 심전도 모니터링인 가능하다면 심장에 부하를 줄 수 있는 운동 중에도 사전에 급작스러운 심장 이상 증세를 예상할 수 있다. 본 연구에서는 일상생활 속에서도 생체신호 측정이 가능한 무구속, 무자각, 무침습적인 심전도 측정 시스템을 개발하였다. 무선 통신을 사용하여 실시간으로 심장 활동 상태를 모니터링 할 수 있으며, 가슴에 부착이 가능한 패치 타입의 소형 전극 형태이다. 신뢰도 평가를 위하여 임상 심전도 신호와 본 전극으로 측정한 심전도 신호의 유사도를 평가하였으며 동잡음의 영향을 평가한 결과 $0{\sim}6m/h$로 걷는 경우, 심전도 파형이 안정적으로 나타나 일상생환에서의 활용가능성을 보여주었다. 동일한 피험자를 대상으로 HRV에 반영되는 스트레스의 영향을 평가하기 위하여 패치형 전극으로 심전도를 측정하여 불안, 스트레스 항목에 대한 설문지 평가, 스트레스 호르몬양을 측정하였다. 일상 상태와 스트레스 상태를 비교한 결과, 많은 파라미터에서 유의한 차이가 나타났다. 이러한 결과로부터 패치형 전극은 일상생활에서 건강 모니터링 시스템으로 활용도가 높을 것으로 기대된다.