지그비를 기반으로 한 운동감시 기능을 가진 1채널 ECG장치 개발

홍주현(Joo-Hyun Hong),김남진(Nam-Jin Kim),차은종(Eun-Jong Cha),이태수(Tae-Soo Lee) 대한전기학회 2005 대한전기학회 학술대회 논문집 Vol.2005 No.10

지그비 기반의 휴대형 심전도 모니터링 시스템 설계

홍주현(Joo-Hyun Hong),김남진(Nam-Jin Kim),차은종(Eun-Jong Cha),이태수(Tae-Soo Lee) 대한전기학회 2006 정보 및 제어 심포지엄 논문집 Vol.2006 No.1

This paper proposes a portable ECG monitoring system, which integrates uptodate PDA and RF communication techNoogy. The aim of the study is to acquire the subject's biomedical signal without any constraint. It has two types of transmission mode, which are total signal transmission mode and HR(heart rate)/SC(step count) transmission mode. In addition, wireless communication techNoogy uses Zigbee Wireless PAN and can work in low-power mode, which is one of the advantages of Zigbee communication techNoogy. The developed system is composed of a transmitter and a receiver. The transmitter has three-axial acceleration sensor, ECG amplifier and Zig bee communication controller. In total signal transmission mode, it can send data 60 packets per second whose transmission speed corresponds to 300 ECG samples and 60 acceleration samples. In HR/SC transmission mode, it can calculate heart rate from ECG data with 216 samples per second and step count from acceleration data and send a packet every cardiac cycle. The receiver forwards the received data to PDA, where the data can be stored and displayed. Therefore. the developed device enables to continuous monitoring for Activities of Daily Living(ADL). Also, this method will reduce medical costs in the aged society.

비만아에서의 leptin, adiponectin, interleukin-6, tumor necrosis factor-α에 대한 연구

길주현,이정아,김지영,홍영미,Gil, Joo Hyun,Lee, Jung Ah,Kim, Ji Young,Hong, Young Mi 대한소아청소년과학회 2008 Clinical and Experimental Pediatrics (CEP) Vol.51 No.6

목 적 : 비만은 지방세포의 축적과 인슐린 내성으로 제 2형 당뇨병을 초래하고, 고 인슐린혈증과 고혈당이 염증 과정의 전구 물질과 함께 작용하여 혈관 내피의 이상, 혈청 지질의 이상, 고혈압과 혈관 염증을 일으켜 동맥경화와 심혈관 질환을 야기하는 것으로 알려져 왔다. Leptin은 adiopnectin과 함께 지방 세포로부터 생산되는 가장 풍부한 adipocytokine으로서, 일차적으로는 식욕 조절과 체내 지방 축적 조절의 기능을 하지만, IL-6, IL-12, TNF-${\alpha}$와 같은 다른 사이토카인과 함께 염증과정의 전구 물질이 되며 여러 면역 관련 질환에서 중요한 매개체가 된다. 이번 연구에서는 비만 청소년에서 leptin과 여러 cytokine과의 상관관계를 알아보고자 하였다. 방 법 : 16세 이상부터 18세 미만의 66명의 중등도 이상의 비만 청소년을 대상군으로 하였고, 같은 연령의 정상 청소년 26명을 대조군으로 하였다. 신장, 체중을 이용하여 비만도와 체질량지수를 산출하였고, 혈청 지질, 간 효소치를 측정하였다. 효소면역 측정법을 이용하여 IL-6, TNF-${\alpha}$를 측정하였고, 방사면역 측정법을 이용하여 adiponectin, leptin, 인슐린을 측정하였다. 이 후 leptin과 각 측정치와의 상관성을 알아보았다. 결 과 : Leptin은 비만군에서 대조군보다 유의하게 높았고, TNF-${\alpha}$와 IL-6도 비만군에서 대조군보다 유의하게 높았다. 인슐린도 비만군에서 대조군보다 유의하게 높았고 adiponectin은 비만군에서 유의하게 낮았다. Leptin은 비만도, 체질량지수, IL-6과 유의한 양의 상관관계를 보였으며, 또한 IL-6와 TNF-${\alpha}$간에 유의한 양의 상관관계를 보였다. 결 론 : 비만 청소년에서 leptin, TNF-${\alpha}$, IL-6와 같은 cytokine과 insulin이 성인병으로 진행되는데 중요한 요소가 될 것이며, leptin을 성인병의 예측 인자 및 임상치료의 척도로 사용하기 위해 더 많은 연구가 필요할 것으로 생각된다. Purpose : Obesity is associated with insulin resistance. Insulin resistance and the presence of pro-inflammatory mediators are thought to cause a state of vascular endothelial dysfunction, an abnormal lipid profile, hypertension, and vascular inflammation. These chronic inflammatory responses, which are characterized by abnormal cytokine production, lead to activation of a pro-inflammatory signaling pathway. Leptin is an important mediator of inflammatory processes and immune-mediated diseases. The purpose of this study was to investigate the relationship between leptin and various cytokines associated with obesity in adolescents. Methods : Sixty-six obese adolescents (between 16-17 years of age, obesity index >130%) and 26 normal controls were included in this study. Obesity index and body mass index (BMI) were calculated. Serum lipid profile, AST and ALT were tested after 10 hours of fasting. Tumor necrosis factor alpha (TNF-${\alpha}$) and Interleukin-6 (IL-6) levels were measured by ELISA. Insulin, adiponectin, and leptin levels were estimated by radioimmunoassay. Results : Leptin was significantly higher in the obese adolescents compared to the control adolescents ($12.0{\pm}6.8ng/mL$ vs $6.3{\pm}1.0ng/mL$). TNF-${\alpha}$, IL-6, and insulin were significantly higher in the obese adolescents. Adiponectin was significantly lower in the obese group than the control group ($3.3{\pm}1.9{\mu}g/mL$ vs $5.0{\pm}1.4{\mu}g/mL$). Leptin had positive correlations with obesity index, BMI, and IL-6. Conclusion : In obese adolescents, leptin, TNF-${\alpha}$, IL-6, and insulin might be important mediators of obesity. Further clinical research is necessary to ascertain leptin as a predictor of cardiovascular diseases and to develop a guideline for clinical intervention.

CDMA망 기반 3채널 심전도 모니터링 시스템의 평가

홍주현,차은종,이태수,Hong, Joo-Hyun,Cha, Eun-Jong,Lee, Tae-Soo 대한의용생체공학회 2008 의공학회지 Vol.29 No.4

A wireless 3 channel ECG monitoring system was developed so that it could monitor the health and movement state during subject's daily life. The developed system consists of a wireless biomedical signal acquisition device, a personal healthcare server, and a remote medical server. Three experiments were performed to evaluate the accuracy, reliability and operability, applicability during daily life of the developed device. First, ECG signals were measured using the developed device and commercial reference device during sitting and marking time and compared to verify the accuracy of R-R intervals. Second, the reliable data transmission to remote server was verified on two types of simulated emergency event using patient simulator. Third, during five types of motion in daily life, the accuracy of data transmission to remote server using CDMA network was verified on two types of event occurring. By acquiring and comparing subject's biomedical signal and motion signal, the accuracy, reliability and operability, applicability during daily life of the developed device were verified. In addition, PDA-phone based wireless system enabled subject to be monitored without any constraints. Therefore, the developed system is expected to be applicable for monitoring the aged and chronic diseased people and giving first-aid in emergency.

휴대형 심전계 장치의 RR 간격의 정확도 개선을 위한 보간법 개발

이은미,홍주현,차은종,이태수,Lee, Eun-Mi,Hong, Joo-Hyun,Cha, Eun-Jong,Lee, Tae-Soo 대한의용생체공학회 2010 의공학회지 Vol.31 No.4

HRV(Heart rate variability) analysis parameter is widely used as an index to evaluate the autonomic nervous system and cardiac function. For reliable HRV analysis, we need to acquire the accurate ECG signals. Most of commercially available portable ECG devices have low sampling rate because of low power consumption and small size issues, which make it difficult to measure RR-interval accurately. This study is to improve the accuracy of RR-interval by developing R-wave interpolation technique, based on the morphological characteristics of the QRS complex. When the developed method was applied to ECG obtained at 200 Hz and the results were compared with 1000 Hz reference device, the error range decreased by 1.33 times in sitting and by 2.38 times in cycling exercise. Therefore, the proposed interpolation technique is thought to be useful to improve the accuracy of R-R interval in the portable ECG device with low sampling rate.

u-Healthcare를 위한 바이오 단말기의 개발 현황

이태수,홍주현,Lee, Tae-Soo,Hong, Joo-Hyun 대한의용생체공학회 2009 의공학회지 Vol.30 No.3

Biomedical mobile devices for ubiquitous healthcare consist of biomedical sensors and communication terminal. They have two types of configuration. One is the sensor-network type device using wired or wireless communication with intelligent sensors to acquire biomedical data. The other is the sensor embedded type device, where the data can be acquired directly by itself. There are many examples of sensor network type, such as, fall detection sensor, blood glucose sensor, and ECG sensors networked with commercial PDA phone and commercial phone terminal for ubiquitous healthcare. On the other hand, sensor embedded type mounts blood glucose sensor, accelerometer, and etc. on commercial phone. However, to enable true ubiquitous healthcare, motion sensing is essential, because users go around anywhere and their signals should be measured and monitored, when they are affected by the motion. Therefore, in this paper, two biomedical mobile devices with motion monitoring function were addressed. One is sensor-network type with motion monitoring function, which uses Zigbee communication to measure the ECG, PPG and acceleration. The other is sensor-embedded type with motion monitoring function, which also can measure the data and uses the built-in cellular phone network modem for remote connection. These devices are expected to be useful for ubiquitous healthcare in coming aged society in Korea.

두께방향 진동형 압전트랜스포머의 특성에 관한 연구

남성이,이수호,홍재일,류주현 ( Seong Yi Nam,Su Ho Lee,Jae Il Hong,Joo Hyun Yoo ) 한국전기전자재료학회 1997 한국전기전자재료학회 추계학술대회논문집 Vol.1997 No.1

휠체어에서 호흡수와 심박수 측정 및 이벤트 전송

한동균,김종명,홍주현,차은종,이태수,Han, Dong-Kyoon,Kim, Jong-Myoung,Hong, Joo-Hyun,Cha, Eun-Jong,Lee, Tae-Soo 대한의용생체공학회 2008 의공학회지 Vol.29 No.6

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.

전왜 액츄에이터용 PBZT 세라믹스의 WO3 첨가에 따른 특성

김규수,윤광희,윤현상,홍재일,류주현,박창엽 ( Kyu Soo Kim,Kwang Hee Yoon,Hyun Sang Yoon,Jae Il Hong,Joo Hyun Yoo,Chang Yub Park ) 한국전기전자재료학회 1997 전기전자재료학회논문지 Vol.10 No.9

휴대형 심전도 모니터링 장치에서의 2가지 호흡 검출 알고리즘

김종명(Jong-Myoung Kim),홍주현(Joo-Hyun Hong),김남진(Nam-Jin Kim),차은종(Eun-Joung Cha),이태수(Tae-Soo Lee) 대한전기학회 2006 정보 및 제어 심포지엄 논문집 Vol.2006 No.1

In this study, two algorithms for detecting respiratory rate from portable ECG device were presented. The first algorithms counts the number of ECG samples between R-R peaks, which varies according to respiratory states of patients, such as, exhalation and inhalation. The second algorithms detects the rate by measuring the size of R wave, which also varies according to the respiratory status of patient. These two algorithms were programmed to the laboratory developed ECG device and their usefulness was verified in laboratory environment.