• Proceedings of the Korean Society of Computer Information Conference
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• 2011.01a
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• pp.111-112
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• 2011

본 연구에서는 광전 용적맥파(photoelectric plethysmography, PPG)를 기반으로 이를 이용하여 혈관 탄성도를 측정 할 수 있는 시스템에 관하여 연구하였다. 광전 용적맥파는 광을 이용한 비 침습적 맥파 측정 방식으로 손가락 끝 부분에서 측정하고 혈액 내에 헤모글로빈의 빛에 대한 광 흡수도의 차이로 인해 나타나게 된다. 얻어진 신호를 2차 미분 하게 되면 가속도 맥파 (acceleration photoplethymogram, APG)를 얻을 수 있고 이는 혈관 탄성도의 추정에 응용가능하다. 본 연구에서는 혈관 탄성도를 측정하기 위한 방법으로 광전 용적맥파를 적용하여 가속도 맥파 측정기기를 설계하고, 이를 바탕으로 혈관 탄성도 추정에 적용 가능 여부를 연구하였다.

• Journal of Acupuncture Research
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• v.28 no.1
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• pp.101-108
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• 2011

목적 : 신정격 자침이 당뇨군과 정상군의 혈관변화에 미치는 영향을 알아보기 위해 가속도맥파를 이용한 실험을 설계하였다. 방법 : 20명의 당뇨군과 20명의 정상군에서 신정격 자침 이전과 이후, 2회에 걸쳐서 Cardio Peri SA6000을 이용하여 가속도맥파를 측정하였다. 가속도맥파의 b/a, c/a, d/a 및 연령지수를 통해 혈관상태를 평가하였다. 결과 : 1. 당뇨군과 정상군의 신정격 자침 이전 가속도맥파 측정에서 당뇨군이 정상군보다 b/a값(p=0.000), 연령지수(AI)(p=0.000)는 유의하게 높았으며, c/a값(p=0.000), d/a값(p=0.000)은 유의하게 낮았다. 2. 당뇨군에서 신정격 자침 이후 가속도맥파의 b/a값(p=0.004), 연령지수(p=0.012)는 유의하게 낮아졌으며, c/a값(p=0.026)은 유의하게 높아졌다. 3. 정상군에서 신정격 자침 이후 가속도맥파의 b/a값(p=0.025)은 유의하게 낮아졌다. 결론 : 신정격 자침이 당뇨로 인해 유발된 혈관의 탄력도 감소 및 노화를 다소 회복시킬 수 있는 것으로 사료된다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.4
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• pp.813-820
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• 2009

This paper describes the realization of ubiquitous healthcare monitoring system using wearable pulse oximeter based on a wireless sensor network. In order to obtain information of oxygen saturation from a patient, a small size and low power consumption wearable pulse oximeter was designed. Information of oxygen saturation collected by wireless sensor node was transmitted wirelessly to a base-station for storage and display purposes via wireless sensor network. Wireless sensor nodes were programmed by TinyOS application to perform data acquisition and transmission. Lab VIEW server program was designed to monitor information of oxygen saturation and process the measured PPG (photo plethysmogram) signals to APG(Accelerated plethysmogram) signals by appling second order derivatives. PPG signals are simple and cost effective technique to measure blood volume change.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.12
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• pp.82-87
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• 2016

The photoplethysmogram (PPG) signal is one of the mainly considered bio signals along with the electrocardiogram (ECG) signal. PPG signals can be used to estimate the speed of flow of blood in vein, saturation of peripheral oxygen and etc. The heartbeat rate is a common feature in order to evaluate those checkup lists. To estimate the correct heartbeat rate, dynamic noises must be removed in the PPG signal. Conventionally, the acceleration signal is used to remove dynamic noises. This method, however, increases the computational complexity. In this paper, we proposes a solution that uses only PPG signals to calculate the heartbeat rate, and which can be used as a basement in real-time healthcare solution.

• Journal of IKEEE
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• v.28 no.2
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• pp.221-227
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• 2024

This paper presents a smartphone-attachable vascular compliance monitoring module. The proposed sensor module measures photoplethysmogram (PPG) and reconstructs an accelerated PPG waveform. The feature points are extracted from the accelerated PPG waves, and vascular compliance is estimated using these extracted features. The module is powered via the smartphone's USB terminal and transmits the acquired waveforms along with vascular compliance values through Bluetooth. The transmitted waveforms and vascular compliance value are displayed through the smartphone application. This work proposes an assessment method for consistency of PPG instrumentation, and it was implemented in a processor of sensor module. The proposed sensor module can be easily attached to smartphone that does not support PPG instrumentation, providing simple measurment and numerical analysis of vascular compliance. To verify the performance of the implemented sensor module, we acquired vascular compliance and pulse pressure data from 29 subjects. Pulse pressure, which serves as a representative indicator of vascular compliance, was obtained using a commercial blood pressure monitor. The analysis results showed that the Pearson coefficient between vascular compliance and pulse pressure was 0.778, confirming a relatively high correlation between two metrics.

• Proceedings of the Korean Society of Computer Information Conference
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• 2011.06a
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• pp.273-276
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• 2011

우리는 감성 공학에 기반하여 일상 생활 속에서 비침습적이면서 사용하기 간편한 광전용적맥파신호를 계측하고 분석하는 이어폰형 생체 신호 측정 시스템에 관하여 연구하였다. 생체 신호 측정 시스템에서는 광전용적맥파(photoplethysmograph, PPG)와 3축 가속도로 생체 신호와 운동 신호를 활용하였다. 수신된 생체 신호인 광전용적맥파 신호는 Peak 검출 및 전처리 알고리즘을 통하여 심박동변동성(heart rate Variablity,HRV)에 대한 시계열 정보로 변환하고 고속 퓨리에 변환(Fast Fourier Transfirm, FFT)과 전력 스펙트럼 밀도 분석(Power Spectrum Density, PSD)방법으로 교감과 부교감 신경 활성도 변화를 관측하였고, 운동 센서로 움직임을 관측하였다. 수신부 시스템은 안드로이드 기반의 자바 어플리케이션으로 스마트 폰에서 구현하였고, 송신부인 이어폰 생체정보 측정모듈로 맥파를 측정하여 상황에 따라 변화하는 자율 신경계의 활성도비율을 확인하였다.

• 대한예방의학회:학술대회논문집
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• 1995.10a
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• pp.277-278
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• 1995

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.293-297
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• 2009

This paper describes a real-time reliable measurement and analysis system for ubiquitous healthcare based on IEEE802.15.4 standard. In order to obtain and monitor physiological body signals continuously, wearable pulse oximeter is designed in wrist that could used to measure oxygen saturation of a patient unobtrusively. The measured data was transferred to a central PC or server by using wireless sensor nodes via a wireless sensor network for storage and analysis purposes. LabVIEW server program was designed to monitor and process the measured photoplethysmogram(PPG) to accelerated plethysmogram(APG) by appling second order derivatives in server PC. These experimental results demonstrate that APG can precisely describe the features of an individual's PPG and be used as estimation of vascular elasticity for blood circulation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.4
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• pp.986-991
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• 2014

The PPG signal used in mobile-healthcare and telemedicine system is including the various motion artifact that is signal generated from patient's movements. Recently, although the various methods to remove motion artifacts have been suggested, the performances of these methods are still not satisfactory. Therefore, this s study suggested the novel method based on the Kalman filter and adaptive filter to remove motion artifacts, and we used various motion artifacts to analyze the performance of the proposed method. In the results of experiments, the signal-to-noise ratio of proposed method showed good performace that was 4.8 times of moving average filter.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.836-837
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• 2014

The electric wheelchair is the vehicle system to support the elderly, infirm, and disabled person. Most of the electric wheelchair is used the encoder sensor for controlling the posture, and the encoder generates the defects caused by frequent mechanical friction. To improve the problem, we have designed the electric wheelchair base on triple acceleration sensor, and implemented. And its performance was evaluated through experiments.