• 대한의용생체공학회:의공학회지
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• 제29권6호
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• pp.443-450
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• 2008

The purpose of this study is to measure both ECG and BCG(Ballistocariograph) signal of a subject on moving or resting wheelchair and detect the heart rate and respiratory rate and transmit an event message to remote server on emergent situation. To acquire ECG and BCG data, amplifier circuits were composed to be suitable for their characteristics. The output signals were converted to digital data and stored in bio-signal archiving media(SD card). CDMA module was used to transmit the event data on ECG electrode detachment and the received data was monitored by the developed C# application program. 5 volunteers participated in the experiment to evaluate the validity of the developed device. When the event occurs in each subject, 48 Kbyte data, stored for 32 seconds from that point, was transmitted to remote server through CDMA cellular phone network correctly. The received data of ECG, BCG, and 3-axial acceleration could be archived in server and the heart rate and respiratory rate could be measured and analyzed. The developed device in this study could acquire the ECG and BCG data of subjects on wheelchair simultaneously and measure their heart rate and respiratory rate. In addition, event data was verified to be transmitted to remote server without any errors.

• 대한의용생체공학회:의공학회지
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• 제37권5호
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• pp.161-167
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• 2016

Recent technological advances in sensor fabrication and bio-signal processing enabled non-constraint and non-intrusive measurement of human bio-signals. Especially, non-constraint measurement of ECG makes it available to estimate various human health parameters such as heart rate. Additionally, non-constraint ECG measurement of wheelchair user provides real-time health parameter information for emergency response. For accurate emergency response with low false alarm rate, it is necessary to discriminate quality levels of ECG measured using non-constraint approach. Health parameters acquired from low quality ECG results in inaccurate information. Thus, in this study, a machine learning based approach for three-class classification of ECG quality level is suggested. Three sensors are embedded in the back seat, chest belt, and handle of automatic wheelchair. For the two sensors embedded in back seat and chest belt, capacitively coupled electrodes were used. The accuracy of quality level classification was estimated using Monte Carlo cross validation. The proposed approach demonstrated accuracy of 94.01%, 95.57%, and 96.94% for each channel of three sensors. Furthermore, the implemented algorithm enables classification of user posture by detection of contacted electrodes. The accuracy for posture estimation was 94.57%. The proposed algorithm will contribute to non-constraint and robust estimation of health parameter of wheelchair users.

• Neonatal Medicine
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• 제16권2호
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• pp.239-243
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• 2009

다소성 심방 빈맥은 신생아에서 드물게 발생하며 진단하기에 어려워 심방 조동으로 오인되기도 한다. 치료가 어려우나 생후 1년 안에 자연적으로 사라지는 경우도 있다. 불규칙한 심방 빈맥을 가진 신생아에게 직접 제작한 경식도 전극을 이용한 심전도를 시행하여 다소성 심방 빈맥을 진단하였다. Propranolol은 치료에 효과적이지 않았으나 digoxin과 sotalol 투여 후 환자는 점차 동리듬으로 회복되었다. 신생아에서 경식도 전극을 이용하여 다소성 심방 빈맥을 진단하였던 1례를 보고한다.

• 한국감성과학회:학술대회논문집
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• 한국감성과학회 2009년도 춘계학술대회
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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.

• 한국의류산업학회지
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• 제22권3호
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• pp.386-398
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• 2020

This study compared dip-coating and in situ polymerization methods for the development of nanofiber-based E-textile using polypyrrole. Nanofiber webs were fabricated by electrospinning an aqueous poly (vinyl alcohol) (PVA) solution. Subsequently, the PVA nanofiber web underwent thermal treatment to improve water resistance. Dip-coating and in situ polymerization methods were used to deposit polypyrrole on the surfaces of the nanofiber web. An FE-SEM analysis was also conducted to examine specimen surface characteristics along with EDS and FT-IR that analyzed the chemical bonding between polypyrrole and specimens. The line resistance and sheet resistance of the treated specimens were measured. Finally, an electrocardiogram (ECG) was measured with textile sensors made of the polypyrrole-deposited PVA nanofiber webs. The polypyrrole-deposited PVA nanofiber webs fabricated by dip-coating dissolved in the dip-coating solution and indicated damage to the nanofibers. However, in the case of in situ polymerization, polypyrrole nanoparticles were deposited on the surface and inter-web structure of the PVA nanofiber web. The resistance measurements indicated that polypyrrole-deposited PVA nanofiber webs fabricated by in situ polymerization with an average sheet resistance of 5.3 k(Ω/□). Polypyrrole-deposited PVA nanofiber webs fabricated by dip-coating showed an average sheet resistance of 57.3 k(Ω/□). Polypyrrole-deposited PVA nanofibers fabricated by in situ polymerization showed a lower line and sheet resistance; in addition, they detected the electrical activity of the heart during ECG measurements. The electrodes made from polypyrrole-deposited PVA nanofiber webs by in situ polymerization showed the best performance for sensing ECG signals among the evaluated specimens.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2006년도 춘계종합학술대회
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• pp.1023-1026
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• 2006

가정이나 병원 등 해상에서 위급한 환자를 모니터링 할 때 현재의 심전도 측정기의 전극센서가 불편할 경우가 많다. 구급차량 내에서나 선박에서 환자를 측정시 흔들림이 심하기 때문에 전극이 떨어져 측정이 쉽지가 않으며 또 환자의 몸에 지방분이나 습기가 많을 경우를 쉽게 붙어있지 않아 측정이 더욱 힘들어진다. 본 연구에서는 환자가 언제든지 전극을 붙이고 화장실이나 외출까지도 자유롭게 할 수가 있도록 하였으며 또 흉부에 쉽게 착용이 용이하도록 부드러운 벤드 형태로 설계되었다. 심전도의 전극소재로는 전기저항특성이 우수하고 피부 트러블이 거의 없는 금을 소재로 한 제품을 적용하였으며 광전용적맥파 및 말초체온 등을 추가로 설계하여 다중생체신호를 모니터링 할 수 있도록 구현하였다. 본 실험에서는 가승이나 늑골부위에서는 생체신호전달이 좋았으며, 환자의 복부부위에서는 생체신호가 아주 작게 검출되었다. 전극소재로 금 전극을 사용하여 일반적인 전극을 이용할 때 보다 신호 검출이 우수하다는 결과를 얻었으며. 일반적인 전극은 단순1회용으로 끝나지만 금 전극센서는 반영구적이면서도 환자가 이동시 접촉력이 우수하여 보다 정확한 데이터를 얻을 수가 있었다.

• 대한의용생체공학회:의공학회지
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• 제33권1호
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• pp.39-46
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• 2012

Electrical impedance tomography(EIT) can produce functional images with conductivity distributions associated with physiological events such as cardiac and respiratory cycles. EIT has been proposed as a clinical imaging tool for the detection of stroke and breast cancer, pulmonary function monitoring, cardiac imaging and other clinical applications. However EIT still suffers from technical challenges such as the electrode interface, hardware limitations, lack of animal or human trials, and interpretation of conductivity variations in reconstructed images. We improved the KHU Mark2 EIT system by introducing an EIT electrode interface consisting of nano-web fabric electrodes and by adding a synchronized biosignal measurement system for gated conductivity imaging. ECG and respiration signals are collected to analyze the relationship between the changes in conductivity images and cardiac activity or respiration. The biosignal measurement system provides a trigger to the EIT system to commence imaging and the EIT system produces an output trigger. This EIT acquisition time trigger signal will also allow us to operate the EIT system synchronously with other clinical devices. This type of biosignal gated conductivity imaging enables capture of fast cardiac events and may also improve images and the signal-to-noise ratio (SNR) by using signal averaging methods at the same point in cardiac or respiration cycles. As an example we monitored the beat by beat cardiac-related change of conductivity in the EIT images obtained at a common state over multiple respiration cycles. We showed that the gated conductivity imaging method reveals cardiac perfusion changes in the heart region of the EIT images on a canine animal model. These changes appear to have the expected timing relationship to the ECG and ventilator settings that were used to control respiration. As EIT is radiation free and displays high timing resolution its ability to reveal perfusion changes may be of use in intensive care units for continuous monitoring of cardiopulmonary function.

• 대한의용생체공학회:의공학회지
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• 제35권5호
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• pp.111-118
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• 2014

As assessment of quantitative energy expenditure for effective exercise is becoming more important, many researches about the monitoring system for exercise status or result have been actively carried out. In this case, however, bicycle riders feel restrained and uncomfortable because the riders should wear a belt-type electrocardiograph or a watch-type accelerometer or GPS system during the assessment of bicycle exercise. In this study, therefore, an electrocardiograph based on textile electrode was developed for measuring ECG and calculating heart rate from the bicycle rider without feeling restraint, and smartphone application was also developed for monitoring the heart rate.

• 한국간호교육학회지
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• 제20권1호
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• pp.60-70
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• 2014

Purpose: Bedside electrocardiograph (ECG) monitoring is continuously used for assessing patients' cardiac status in intensive care units. However, it has not been explored whether it is used with proper knowledge and nursing practices; if not, its usage will be limited and the risk for compromised patient safety might be significant. This study, therefore, explored knowledge and nursing practices regarding bedside ECG monitoring in nurses working at intensive care units. Methods: Participants in this survey research were a convenience sample of 156 nurses from 25 intensive care units distributed in five hospitals with more than 1,000 beds each in Seoul, South Korea. Results: Participants showed limited and incorrect knowledge and nursing practices. Only 4 (2.6%) participants correctly answered to all electrode placement sites of RA, LA, LL, and V1. Lead II was the most frequently monitored unit regardless of the main purpose of ECG monitoring, and nursing practices to manage noisy signals did not include skin care at the top priorities. Conclusion: Educators and clinicians alike need to make an effort to ensure that a safe level of knowledge and practices for the monitoring is maintained in order to make sure that patient outcomes are not compromised.

• 전기학회논문지
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• 제56권9호
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• pp.1688-1693
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• 2007

The aim of this paper is to develop and verify the system which can detect heart rate during exercise by using conductive fabric electrode and transportable measurement module. The experiment was performed under 4 conditions(resting, walking, jogging, running) and 18 subjects data are used. By using the ECG measurement system used in cardiac stress testing as reference value in order to verify the accuracy of the developed system, the relative error and correlation coefficient was calculated for each subject at every 3 seconds. The results have shown that the high correlation between the developed system and the reference system for detecting heart rate during exercise. Relative error and correlation coefficient are 2.27% and 0.9877, respectively. 7 subjects data are omitted in these calculations because of severe noises. Therefore, it is expected that this system could be used as a health monitoring system in ubiquitous environment in the future.