• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2007년도 춘계학술대회 논문집
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• pp.695-696
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• 2007

• 센서학회지
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• 제18권5호
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• pp.359-364
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• 2009

This paper presents flexible electrocardiography(ECG) sensors using micro electro mechanical systems(MEMS) and flexible printed circuit(FPC) technology. By using FPC technology, ECG sensors which consisted of an outer hook-shaped electrode and an inner circular-shaped electrode were fabricated on the polyimide substrate. Thereafter, the bipolar ECG sensor was miniaturized using MEMS technology. The ECG measurement capability was examined by attaching the sensor to the human chest and wrist. Performance of the proposed sensors was then compared with ECG measured by commercial Ag/AgCl electrodes. It was verified that ECG could be measured using proposed sensors at only single body.

• 대한의용생체공학회:의공학회지
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• 제35권5호
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• pp.125-131
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• 2014

The purpose of this study is to verify the utility of reflected photoplethysmography sensor using two green light emitting diodes that influenced by ambient light. Recently it has been studied that green light emitting diode is suitable for light source of reflected photoplethysmography sensor at low temperature and high temperature. Another study showed that, green light is better for monitoring heart rate during motion than led light. However, it has a bad characteristic about ambient light noise. To verify the utility of reflected photoplethysmography sensor using green light emitting diode, this study measures the photoplethysmography signal that is distorted by ambient light and will propose a solution. This study has two parts of research method. One is measurement system that composed sensor and board. The sensor is made up PE-foam and Non-woven fabric for flexible sensor. The photoplethysmography signal is measured by measurement board that composed high-pass filter, low-pass filter and amplifier. Ambient light source is light bulb and white light emitting diode that has three steps brightness. Photoplethysmography signal is measured with lead II electrocardiography signal at the same time and it is measured at the finger and radial artery for 1 minute, 1000 Hz sampling rate. The lead II electrocardiography signal is a standard signal for heart rate and photoplethysmography signal that measured at the finger is a standard signal for waveform. The test is repeated 3 times using three sensor. The data is processed by MATLAB to verify the utility by comparing the correlation coefficient score and heart rate. The photoplethysmography sensor using two green light emitting diodes is shown better utility than using one green light emitting diode and red light emitting diode at the ambient light. The waveform and heart rate that measured by two green light emitting diodes are more identical than others. The amount of electricity used is less than red light emitting diode and error peak detectability factor is the lowest.

• 센서학회지
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• 제27권5호
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• pp.340-344
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• 2018

Electrodes are an important part of electrocardiography (ECG); disposable electrodes have been extensively used. However, personal ECG monitoring devices for Internet of Things applications require reusable electrodes. As there have been no systematic studies on the characteristics of reusable electrodes to date, we conducted this study to assess the performance and feasibility of electrodes with different materials. We built reusable electrodes using twelve different metallic materials, including commonly used copper, silver, zinc, plating materials, chemically inert titanium, stainless steel, and aluminum. Each electrode was fabricated to a size of $5{\times}10mm$. Their characteristics such as offset, baseline drift, stabilization time, and chemical inertness were compared. A personal ECG monitoring system was used to test the manufactured electrodes. The performances of the Ag, Cu, and Zn electrodes were better than the performances of other electrodes. However, these materials may not be used owing to the chemical changes that occur when the electrodes are in contact with the skin, such as discoloration and corrosion, which deteriorate their electrical characteristics. Titanium, stainless steel, and aluminum are chemically stable. The titanium electrode showed the best performance among the three, and it is our recommendation as a material for manufacturing reusable electrodes.

• 센서학회지
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• 제25권2호
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• pp.131-137
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• 2016

In this study, a multilevel visible light communication (VLC) system based on resistor ladder circuit is designed to transmit medical data. VLC technology is being considered as an alternative wireless communication due to various advantages such as ubiquity, license free operation, low energy consumption, and no radio frequency (RF) radiation characteristics. With VLC even in places where traditional RF communication (e.g., Wi-Fi) is forbidden, significant bio-medical signal including the electrocardiography (ECG) and photoplethysmography (PPG) data can be transmitted. More lives could be saved anywhere by this potential advantage of VLC with a fast emergency response time. A multilevel transmission scheme is adopted to improve the data capacity with keeping simplicity, where data transmission rate can increase by log2m times (m is the number of voltage levels) than that of conventional VLC transmission based on on/off keying. In order to generate multi-amplitudes, resistor ladder circuit, which is a basic principle of digital to analog convertor, is employed, and information is transferred through LED (Light-Emitting Diode) with different voltage level. In the receiver side, multilevel signal is detected by optical receiver including a photo diode. Then, the collected data are analyzed to serve the necessary medical care to the concerned patient.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2005년도 추계종합학술대회
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• pp.493-496
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• 2005

For home healthcare, the unconstrained measurement of physiological signal is highly required to avoid the inconvenience of users. The recording and analysis of the fundamental parameters during sleep like respiration and heart beat provide valuable information on his/her healthcare. Using the air mattress sensor system, the respiration and heart beat movements can be measured without any harness or sensor on the subject's body. The differential measurement technique between two air cells is adopted to enhance the sensitivity. The balancing tube between two air cells is used to increase the robustness against postural changes during the measurement period. The meaningful frequency range could be selected by the pneumatic filter with balancing tube. ECG (Electrocardiography) and respiration sensor (plethysmography) were measured for comparison with the signal from air mattress. To extract the heart beat information from air pressure sensor, digital signal processing technique was used. The accuracy for breathing interval and heart beat monitoring was acceptable. It shows the potentials of air mattress sensor system to be the unconstrained home sleep monitoring system.

• 한국의류학회지
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• 제36권11호
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• pp.1174-1185
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• 2012

This study develops tight-fitting upper clothing to measure electrocardiography (ECG) data. Taking into consideration the elasticity of the clothing, we made 4 experimental clothes by applying to each a weft reduction rate of 40%, 50%, 60%, and 70%. The 4 experimental clothes were used to measure resting ECG, exercise ECG, and post-exercise ECG for 4 men in their 20s. We compared clothing pressures using sensors on the human body and on a dressform. Subjective wear sensations of the 4 experimental clothes were evaluated using a subjective 7-point scale (with 7 being most excellent). We measured clothing pressures by using the air type pressure (AMI 3037-2) for upper and lower chest sensors in the developed tight-fitting upper clothing. The lower chest sensor showed that the clothing pressure on a human body and dressform changed consistently as the weft reduction rate decreased. The upper chest sensor showed inconsistent changes in clothing pressure as the weft reduction rate decreased. The wearing-test result for preliminary subjects showed that the lower chest sensor was more stable than the upper chest sensor; therefore, we inserted the sensor at the lower chest position before performing ECG. Except for Subject 4, the resting ECGs were stably measured for 3 subjects (Subject 1, Subject 2, and Subject 3) in all the developed clothes (A clothing, B clothing, C clothing, and D clothing). However, D clothing showed stable ECG values after exercise. The results of the experiment showed that we could measure ECG without difficulty using clothes with a weft reduction rate of 40% when the movement was not intense; however, tight-fitting upper clothing with a weft reduction rate of 70% was necessary to measure exercise ECG and post-exercise ECG values.

• 한국전자통신학회논문지
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• 제14권6호
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• pp.1257-1264
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• 2019

기존의 Cuff 기반의 혈압(Blood Pressure)측정 방법은 연속적인 실시간 혈압측정에는 한계를 갖는다. 이러한 이유로 ECG와 PPG 센서 신호를 상호융합한 다양한 혈압추정이 이루어졌다. 그러나 PPG 중심에 측정기법은 AC 노이즈, 작은 맥동, 비박동 등의 많은 문제를 지니고 있다. 본 논문은 ECG와 PPG 관계에 발생하는 맥파전달시간(PTT)과 맥파속도(PWV)를 이용하여 혈압을 추론기법이다. 신호 피크를 이용하는 HRF(Height Ratio Features)에 비해, 본 제안방식은 ECG, PPG의 최고점 혹은 최저점을 사용한 시차를 이용해 추정하기 때문에 PPG 센싱 시그널의 오류에도 안정적인 추출이 가능한 장점이 있다. 본 논문에서 제안 방법을 이용하여 25만 회의 혈압측정의 결과 ±28.5%의 정확도를 갖는 혈압 추정기법을 제시할 수 있었다.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2016년도 춘계학술발표대회
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• pp.865-867
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• 2016

본 논문에서는 섬유근접센서를 이용하여 측정한 맥박을 평가하기 위해 Biopac MP150에서 획득한 Electrocardiography(ECG)와의 관계를 보았다. 섬유근접센서는 요골동맥에서의 맥박을 측정하기 위해 $5{\times}5$ 크기로 설계하였고, 전처리 과정과 필터링을 거쳐 획득한 데이터 값은 ECG 데이터와 Peak Point의 개수를 비교하여 올바른 맥박이 측정되었는지를 판단하였다. 그 결과 섬유근접센서와 MP150에서 측정한 두 데이터의 Peak Point가 모두 동일한 결과를 보였다.

• 한국위성정보통신학회논문지
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• 제9권2호
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• pp.80-84
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• 2014

유헬스는 정보통신기술과 생체의료기술을 융합하여 사용자에게 시간 및 공간적 제약이 없이 건강관리 및 의료 서비스를 제공하는 기술이다. 의사가 사용자의 건강상태를 원격으로 진단하기 위해서는 유헬스 기기의 생체신호 측정 기술과 측정된 생체 신호를 전송하는 통신 기술이 중요하다. 본 논문에서는 심전도측정센서, 영상모듈, GPS모듈, 통신모듈 및 MCU(Micro Controller Unit)를 이용하여 사람의 생체신호 중 심전도신호를 측정하여 영상 및 사용자의 위치정보를 무선으로 전송하는 생체신호 모니터링 시스템을 구현하는 과정을 소개한다.