• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.893-894
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• 2006

DSP based on a 8 bit microprocessor was studied for ECG and PPG signals. Digital filtering has an advantage of reducing hardware components in system-on-chip design. However, low resolution such as in 8 bit data has much difficulties in DSP. We demonstrated a comparable performance of DSP filtering compared with analog filters.

• 센서학회지
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• 제15권5호
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• pp.334-340
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• 2006

A compact biosignal monitoring device was developed. Electrodes for electrocardiogram (ECG) and a LED and silicon detector for photoplethysmogram (PPG) were used. A lead II type was arranged for ECG measurement and reflected light was measured at the finger tip for PPG. A single chip microprocessor (model ADuC812, Analog Device) controlled a measurement protocol and processed measured signals. PPG and ECG had a sampling rate of 300 Hz with 8-bit resolution. The maximum power consumption was 100 mW. The microprocessor computed pulse transit time (PTT) between the R-wave of ECG and the peak of PPG. To increase the resolution of PTT, analog peak detectors obtained the peaks of ECG and PPG whose interval was calculated using an internal clock cycle of 921.6 kHz. The device was designed to be operated by 3-volt battery. Biosignals can be measured for $2{\sim}3$ days continuously without the external interruptions and data is stored to an on-board memory. Our system was successfully tested with human subjects.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 춘계학술대회
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• pp.285-289
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• 1997

In this paper, we describe the intrabed and interbed network in a developed patient monitoring system. Intrabed network handles data communication among the main unit of a bedside monitor and parameter modules plugged in it. Interbed network deals with a higher level data communication among many bedside monitors, central stations, DB servers, and clinical workstations. Analyzing the data communication requirements in each stage of the system, we designed the intrabed network based upon RS-485 and HDLC protocol with 1Mbps data rate. Interbed network is designed to utilize the industry standard 10Base-T Ethernet with TCP/IP and UDP protocol. We present the specifications and the performances of the developed data communication networks in the patient monitoring system.

• 임상이비인후과
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• 제29권2호
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• pp.167-172
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• 2018

• 대한의용생체공학회:의공학회지
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• 제28권2호
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• pp.258-264
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• 2007

Spatiotemporal changes of brain rhythmic activity at a certain frequency have been usually monitored in real time using scalp potential maps of multi-channel electroencephalography(EEG) or magnetic field maps of magnetoencephalography(MEG). In the present study, we investigate if it is possible to implement a real-time brain activity monitoring system which can monitor spatiotemporal changes of cortical rhythmic activity on a subject's cortical surface, neither on a sensor plane nor on a standard brain model, with a high temporal resolution. In the suggested system, a frequency domain inverse operator is preliminarily constructed, considering the individual subject's anatomical information, noise level, and sensor configurations. Spectral current power at each cortical vertex is then calculated for the Fourier transforms of successive sections of continuous data, when a single frequency or particular frequency band is given. An offline study which perfectly simulated the suggested system demonstrates that cortical rhythmic source changes can be monitored at the cortical level with a maximal delay time of about 200 ms, when 18 channel EEG data are analyzed under Pentium4 3.4GHz environment. Two sets of artifact-free, eye closed, resting EEG data acquired from a dementia patient and a normal male subject were used to show the feasibility of the suggested system. Factors influencing the computational delay are investigated and possible applications of the system are discussed as well.

• Journal of information and communication convergence engineering
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• 제5권1호
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• pp.7-11
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• 2007

The aim of this paper is to design and implement a new ECG signal monitoring and analysis method for the home care of elderly persons or patients, using wireless sensor network (WSN) technology. The wireless technology for home-care purpose gives new possibilities for monitoring of vital parameter with wearable biomedical sensors and will give the patient freedom to be mobile and still be under continuously monitoring. Developed platform for portable real-time analysis of ECG signals can be used as an advanced diagnosis and alarming system. The ECG features are used to detect life-threatening arrhythmias, with an emphasis on the software for analyzing the P-wave, QRS complex, and T-wave in ECG signals at server after receiving data from base station. Based on abnormal ECG activity, the server transfer diagnostic results and alarm conditions to a doctor's PDA. Doctor can diagnose the patients who have survived from arrhythmia diseases.

• 한국운동역학회지
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• 제18권2호
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• pp.59-64
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• 2008

본 연구는 3축 가속도 센서를 허리에 부착하여 실시간으로 스포츠 동작분류를 할 수 있는 모니터 링에 관한 연구를 실시하였다. 이 모니터링 시스템은 스포츠 동작의 기본이라고 할 수 있는 걷기, 달리기, 자세변화 동지 정지상태의 동작들과 추가적으로 사이클링 동작을 분류할 수 있도록 하였다. 또한 운동 시에 발생할 수 있는 낙상을 감지하여 위급상황에 대한 정보도 나타나게 하였다. 가속도센서모듈은 인체에 부착된 형태로 스포츠 활동을 모니터링하기 위하여 소형으로 설계되었으며 활동에 방해가 되지 않게 허리에 부착되었다. 측정된 데이터는 RF통신을 통해 PC로 전송되며 알고리즘을 통해 실시간으로 동작분류를 시행하게 된다. 개발된 알고리즘을 검증하기 위한 실험으로 5명의 피험자를 대상으로 서로 다른 속도의 걷기, 달리기, 사이클링 동작을 각각 100초간 실시하였으며 낙상과 자세변화 동작(앉았다 일어서기, 누웠다 일어서기, 서있다 앉기, 누웠다 앉기, 서있다 눕기, 앉았다 눕기)은 각각 20회씩 실행하였다. 그 결과 동작분류 정확도는 95.4%를 나타내었다. 이번 연구에서 스포츠 모니터링을 통하여 정확한 자신의 운동 정보를 알려주고 운동 시에 발생하는 낙상에 대한 위급상황을 알려줌으로써 스포츠 활동에 도움을 주고자 하였으며, 추가적인 연구로 각각의 스포츠 활동에 대한 정확한 에너지 소비 추정 알고리즘을 개발 중에 있다.

• 대한의용생체공학회:의공학회지
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• 제38권3호
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• pp.111-115
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• 2017

Blood pressure is one of the important vital signs for monitoring the medical condition of a patient. Automated NIBP(non-invasive blood pressure) monitoring devices calculate systolic and diastolic blood pressures from the oscillation in cuff pressure caused by a pulsation of an artery. To validate the NIBP devices, we developed a simulator to supply the oscillometric waveforms obtained from human subjects. The simulator provided pressure pulses to device-under-test and device readings were compared to the auscultatory references. Fully automated simulation system including OCR(optical character recognition) were developed and used for NIBP monitoring devices. The validation results using the simulator agreed well with previous clinical validation. More validation studies using the standardized oscillometric waveforms would be required for the replacement of clinical trials to validate a new automated NIBP monitoring device.

• 전자공학회논문지
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• 제54권7호
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• pp.103-109
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• 2017

병원 현장에서 환자 모니터링 시스템을 적용하기 위해서는 환자감시장치에서 기본적으로 다루고 있는 주요 생체신호의 측정과 데이터의 분석이 가능해야 한다. 본 논문에서는 이러한 요구사항을 수용하고자 심전도와 산소포화도 측정이 가능한 웨어러블 디바이스와 환자 모니터링 시스템을 구현하였다. 구현된 시스템은 측정된 생체신호를 블루투스를 통해 간호스테이션 상의 서버로 전송되고 환자 모니터링 시스템에서 의료진이 확인할 수 있는 그래프 파형과 수치로 표현된다. 설계한 시스템을 통해 수집된 데이터와 기존 장비에서 얻어진 데이터를 비교하여 본 시스템의 유효성을 검증하였다.

• 대한의용생체공학회:의공학회지
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• 제35권3호
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• pp.55-61
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• 2014

In sleep monitoring system, polysomnography (PSG) is the gold-standard but previous studies revealed that attaching numerous amount of sensors disturb sleep during the test which is the fundamental disadvantage of PSG. We suggest an unconstrained rapid-eye-movement (REM) sleep monitoring method measured with polyvinylidene (PVDF) film-based sensor for the normal and the obstructive sleep apnea (OSA) patients. Nine normal subjects and seventeen OSA patients have participated in the study. During REM sleep, rate and variability of respiration are known to be greater than in other sleep stages. Based on this phenomena, respiratory signals of participants were unconstrainedly measured using the PVDF-based sensor with the PSG and REM sleep were extracted from the average rate and variability of respiration. In epoch-by-epoch REM sleep detection, proposed method classified REM sleep with an average sensitivity of 72.3%, specificity of 92.5%, accuracy of 88.9%, and kappa statistic of 0.60 compared to the results of PSG. Student's t-test showed no significant difference between the results of normal and OSA group. This method is potentially applicable to REM sleep detection in homing environment or ambulatory monitoring.