• 센서학회지
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• 제13권6호
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• pp.462-472
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• 2004

In this study, we measured the blood flow on arm by non-invasive method and implemented a system to measure variation of the blood flow by estimating bio-electrical impedance and arterial pressure according to cuff pressure. The implemented system measured impedance variation according to pressure variation applied by artificial cuff pressure on the measuring position. The system consisted of pressure measuring part and impedance measuring part using 4-electrode method. Pressure measuring part was composed of semiconductor pressure sensor and electronic circuit for signal processing of sensor output signal. In addition, impedance measuring part was composed of constant current source circuit and lock-in amplifier for detecting impedance signal. We conducted experiments of impedance measuring part using standard resistance for performance evaluation of the implemented system. In addition we experimented to estimate variation of the blood flow by measuring impedances of the experimental group. We estimated ratio of the blood flow resistance using mean arterial pressure and variation of the blood flow. As a result the ratio of the blood flow resistance and variation of blood flow were in an inverse relationship with each other and the correlation coefficient was -0.96776.

• 한국정보통신학회논문지
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• 제22권8호
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• pp.1083-1089
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• 2018

대뇌혈류를 증가 시키는 수술은 뇌경색의 치료방법중 하나이다. 이러한 침습적인 방법을 보완하기 위해 사람의 혈압을 이용해, 사지에 압박을 가하여 대뇌 혈류를 증가 시키는 비 침습적인 장치도 등장하였다. 그러나 속도와 정확성이 떨어지는 문제점이 제기되었다. 본 논문에서는, 정확한 측정과 측정하는 데에 걸리는 시간을 기존의 장치보다 개선하기 위해, Blood Oxygen Level Sensor를 이용하여, 양팔에 압력을 주면서 각 팔의 Perfusion Index를 측정하여, Perfusion Index가 일정 값 이하로 떨어지는 순간의 75% 압력을 팔에 가하고, 다리에는 팔에서 구해진 압력 값을 이용해 계산하여 얻은 압력을 가한다. 기존의 혈압 측정식 대뇌혈류증가 장치와 같이, 혈류량을 20%이상 증가 시킬 수 있고, 또한 측정 시간도 단축한 결과를 얻어 뇌경색 환자에게 선택적으로 사용할 수 있다.

• 한국전기전자재료학회논문지
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• 제26권3호
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• pp.171-176
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• 2013

In this paper, we present a MEMS (micro-electro-mechanical system) implantable blood pressure sensor which has designed and fabricated with consideration of size, design flexibility, and wireless detection. Mechanical and electrical characterizations of the sensor were obtained by mathematical analysis and computer aided simulation. The sensor is composed of two coils and a air gap capacitor formed by separation of the coils. Therefore, the sensor produces its resonant frequency which is changed by external pressure variation. This frequency movement is detected by inductive coupling between the sensor and an external antenna coil. Theoretically analyzed resonant frequency of the sensor under 760 mmHg was calculated to 269.556 MHz. Fused silica was selected as sensor material with consideration of chemical and electrical reaction of human body to the material. $2mm{\times}5mm{\times}0.5mm$ pressure sensors fitted to radial artery were fabricated on the substrates by consecutive microfabrication processes: sputtering, etching, photolithography, direct bonding and laser welding. Resonant frequencies of the fabricated sensors were in the range of 269~284 MHz under 760 mmHg pressure.

• Journal of Computing Science and Engineering
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• 제2권2호
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• pp.180-199
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• 2008

Technology has had a tremendous impact on our daily lives. Recently, technology and its impact on aging has become an expanding field of inquiry. A major reason for this interest is that the use of technology can help older people who experience deteriorating health to live independently. In this paper we give a brief review of the in-home monitoring technologies for the elderly. In the pilot study, we analyze the possibility of employing the data generated by a continuous, unobtrusive nursing home monitoring system for predicting elevated(abnormal)pulse pressure(PP) in elderly(PP=systolic blood pressure-diastolic blood pressure). Our sensor data capture external information(behavioral) about the resident that is subsequently reflected in the predicted PP. By continuously predicting the possibility of elevated pulse pressure we may alert the nursing staff when some predefined threshold is exceeded. This approach may provide additional blood pressure monitoring for the elderly persons susceptible to blood pressure variations during the time between two nursing visits. We conducted a retrospective pilot study on two residents of the TigerPlace aging in place facility with age over 70, that had blood pressure measured between 100 and 300 times during a period of two years. The pilot study suggested that abnormal pulse pressure can be reasonably well estimated (an area under ROC curve of about 0.75) using apartment bed and motion sensors.

• 대한의용생체공학회:의공학회지
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• 제25권6호
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• pp.599-604
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• 2004

본 논문에서는 폴리머/ 금속 다층 공정 기술 (polymer/metal multi layer processing techniques)을 이용한 실시간 혈압 감지를 위한 유연한 생체 삽입형 센서를 새로이 제안한다. 제안되는 방식의 센서는 기계적으로 유연하기 때문에 혈관의 외벽에 대한 침습성을 감소시켜 부착할 수 있다. 즉, 혈압 측정을 위해 센서를 혈관 내에 설치하던 기존의 방법들에 비해서 혈관 자체에 상처를 주지 않고 혈압의 상대적인 변화를 지속적으로 감지할 수 있다. 성인에게 발생하는 급사의 주된 원인은 협심증, 심근 경색과 같은 혈관 관련 질환이다. 플라크 (plaque)의 생성 등과 관계된 순환계 관련 질환들은 지속적인 혈압 감지를 통해서 예방할 수 있으며 발병 초기에 치료할 수 있다. 본 연구에서 제안하는 혈압감지 방법의 과정은 다음과 같다. 우선, 집적된 센서를 혈관 외벽에 부착한다. 둘째, 실장된 센서가 혈관의 기계적인 수축과 확장을 인식한다. 마지막으로, 센서에 의해 인식된 혈압의 변화를 원격 감지 방법을 통해서 외부 안테나에서 감지하게 된다. 센서 시스템에는 어떠한 능동 소자도 존재하지 않기 때문에 에너지와 혈압 변화 정보는 LC 공진기와 외부 안테나 사이에 발생하는 상호 인덕턴스 원리에 의해서 전달되게 된다. 이러한 측정 원리의 가능성을 확인하기 위해서 실리콘 고무관과 혈액을 이용하여 시험관 실험 (In vitro test)을 진행하였다. 우선, 혈액으로 채운 실리콘 고무관에 센서를 감은 후 피스톤으로 압력을 가하였다. 그리고 이를 통해 가해진 압력 변화에 따른 공진 주파수의 변화를 측정하였다. 가해진 압력이 0부터 213.3 KPa까지 변화하는 동안 2.4 MHz의 공진 주파수가 변했다. 그러므로 생체 삽입형 혈압 센서의 감도는 11.25 KHz/KPa이다.

• 대한의용생체공학회:의공학회지
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• 제29권3호
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• pp.239-248
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• 2008

In this study, a new method using a capacitive sensor and an adaptive filter was proposed to deal with artifacts contaminating an oscillation signal in oscilometric blood pressure measurement. The proposed method makes use of a variation of the capacitance between an electrode fixed to a cuff and an external object to detect artifacts caused by the external object bumping into the cuff. The proposed method utilizes the adaptive filter based on linear prediction to remove the detected artifacts. The conventional method using linear interpolation and the proposed method using the adaptive filter were applied to three types of the artifact-contaminated oscillation signals(no overlap, non-consecutive overlap, and consecutive overlap between artifacts and oscillations) to compare them in terms of the artifact reduction performance. The proposed method was more robust than the conventional method in the case of consecutive overlap between artifacts and oscillations. The proposed method could be useful for measuring blood pressure in such a noisy environment that the subject is being transported.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2016년도 추계학술대회
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• pp.915-918
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• 2016

의료산업의 급속한 변화와 의료 및 간호 인력의 증가로 인하여 가상 시험 장치에 대한 개발이 요구되고 있으며 심장 모델링할 수 있는 시뮬레이터와 혈관, 혈류에 대한 실습장비에 대한 개발의 중요성이 증가하고 있다. 따라서 본 연구에서는 스텝 모터를 이용하여 심장 펌프를 제작하여 동맥과 정맥 혈압, 혈류 시뮬레이션을 위한 장비를 개발하고 그 기능을 평가하고자 한다. 제안 시스템은 심장 시뮬레이션을 위한 펌프와 동맥, 정맥 혈관의 저항을 모사하기 위한 밸브장치 그리고 정맥계의 특성을 나타내는 저감장치로 구성한다. 심장 시뮬레이터는 롱거펌프(BOXER)를 사용하였으며 동맥과 정맥혈관은 실리콘 튜브를 사용하고 저감장치를 설계 및 제작하였다. 그리고 동맥혈압 측정을 위하여 압력센서를 사용하였다. 또한 제안 시스템의 평가를 위하여 심장 박동수는 분당 60회로 혈압의 범위는 50 ~ 100mmHg로 선정하여 측정 혈압과 사람의 혈압을 비교 평가하였다.

• 센서학회지
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• 제24권4호
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• pp.239-246
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• 2015

Blood pressure is possible to diagnose a disease associated with blood pressure and judgment the current health of patients. Automatic blood pressure monitor capable of measuring a blood pressure easily in hospital and at home have become spread. In this study, we developed the blood pressure simulator (BPS) that can test the arm-type automatic blood pressure monitor that is commonly used in hospital. BPS is to produce a pressure similar to the pressure wave generated in the human blood using a servo disk motor. Then, using the silicon tube, it implements the situations such as human blood vessels, and to output the generated pressure waveform. Simply the BPS's phantom put on the cuff and it is able to simulate blood pressure. So anyone can quickly test the blood pressure monitor within one minute and it is possible to shorten the test time required for the automatic blood pressure monitor. In Performance test, the trends and the standard deviation of the values measured in the BPS is similar to the value of the measured pressure from people with normal blood pressure. Thus, the development BPS showed a possibility of taking into account the actual blood pressure measurement environment simulator.

• International journal of advanced smart convergence
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• 제1권2호
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• pp.20-25
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• 2012

The oscillometric method and Korotkoff sound method are the most common ways to measure the blood pressure. A new automatic blood pressure measurement device, which uses both oscillometric method and Korotkoff method, was developed. A pressure sensor was used to obtain cuff pressure and oscillation signal, and a microphone was used to detect Korotkoff sounds. Forty-five measurements from fifteen subjects were used for analysis. Correlation coefficients between the traditional auscultatory method and Korotkoff sound method were 0.9820 and 0.9721 for the systolic and diastolic blood pressure values, respectively. Standard deviations of differences for the systolic and diastolic blood pressure values were 1.3019 and 1.4495, respectively. Correspondingly, correlation coefficients between the traditional auscultatory method and oscillometric method using newly developed algorithm were 0.9651 and 0.9136 for the systolic and diastolic blood pressure values, with the standard deviations of 1.42 and 1.73, respectively. The results showed that the newly developed algorithm for oscillometirc method provide accurate blood pressure values, moreover, Korotkoff sound method using microphone provides even higher accuracy. Therefore, a new automatic device which utilizes both oscillometric method and Korotkoff sound method would provide the accurate and reliable blood pressure values.

• Journal of Biosystems Engineering
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• 제17권4호
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• pp.404-409
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• 1992

It is important to measure the somatic informations for stockbreeding automatization. This study was carried out for the development of wireless measurement system of sphygmus in living animals. In meauring sphygmus counting with the single-channel telemety system, a LED-photo transistor sensor showed more sensitivity to the change of blood pressure than a piezo-electric sensor based pressure sensor. The LED-photo transistor sensor resulted ${\pm}1.29%$ of measurement error of sphygmus counting. In the process of transmitting and receiving the blood pressure signal for counting sphygmus, noises were mixed with, and the noises made the counting almost impossible. Auto-correlation analysis technique was applied to the signal data to extract the sphygmus information, and the technique was proved to be very effective.