• 한국가시화정보학회지
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• 제8권1호
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• pp.46-52
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• 2010

In the present study, we employed the confocal laser scanning microscopy (CLSM) system to visualize the blood flow field with $1{\times}1{\mu}m^2$ spatial resolution. Based on the confocal microscopic image of red blood cells (RBCs), we performed the velocity vector field measurement and evaluated characteristics of cell migration from the cell depleted layer thickness calculation. The rat and mouse's blood were supplied into a micro glass tubes in vitro. The line scanning rate of confocal microscopy was 15 kHz for a $500{\times}500$ pixels image. As a result, the red blood cell itself can be used as a tracer directly without any kind of invasive tracer particle to get the velocity vector field of blood flow by performing particle image velocimetry (PIV) technique.

• 대한수의학회지
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• 제37권3호
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• pp.661-668
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• 1997

Portal blood flow was measured with pulsed doppler ultrasound in thirty normal dogs. In normal dogs, the average portal blood flow velocity was $17.03{\pm}1.75cm/sec$ and the average portal blood flow was $41.59{\pm}10.10ml/min/kg$. The incident angle between the doppler beam and the portal vein averaged $65^{\circ}$. The average portal vein sectional area was $0.41{\pm}0.14cm^2$. The Congestion index was $0.0245{\pm}0.0081cm{\cdot}sec$. Conclusively, the spectral doppler ultrasonography was quick, non-invasive and simple diagnostic method in circulatory disorders of liver.

• 센서학회지
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• 제20권5호
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• pp.343-350
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• 2011

The compliance and stiffness of artery are closely related with disease of arteries. Pulse wave velocity(PWV) in the blood vessel is a basic and common parameter in the hemodynamics of blood pressure and blood flow wave traveling in arteries because the PWV is affected directly by the conditions of blood vessels. However, there is no standardized method to measure the PWV and it is difficult to measure. The conventional PWV measurement has being done by manual calculation of the pulse wave transmission time between coronary arterial proximal and distal points on a strip chart on which the pulse wave and ECG signal are recorded. In this study, a pressure sensor consisting of strain gauges is used to measure the blood pressure of arteries in invasive method and regular ECG electrodes are used to record the ECG signal. The R-peak point of ECG is extracted by using a reference level and time windowing technique and the ascending starting point of blood pressure is determined by using differentiation of the blood pressure signal and time windowing technique. The algorithm proposed in this study, which can measure PWV automatically, shows robust and good results in the extraction of feature points and calculation of PWV.

• 한국한의학연구원논문집
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• 제13권3호
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• pp.111-117
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• 2007

The study aims to measure and analyze the thickness and depth of blood vessel on the pulse diagnosis locations and the blood velocity through the use of ultrasonic waves (LOGIQ5PRO, GE Medical, U.S.) in order to understand the structural difference of pulse diagnosis locations. The subjects included 44 healthy men and women(22.28${\pm}$2.62 age) considered normal in terms of Body Mass Index(BMI). The thickness and depth of the blood vessel and the blood velocity were measured three times on CHON, KWAN and CHUCK to obtain the average value. Results showed there is a statistically significant difference among the variables measured on CHON, KWAN and CHUCK. A difference according to gender was also observed. This explains why an oriental medical doctor can tell the difference in pulses depending on the location of CHON, KWAN and CHUCK. In addition, the difference in pressure between CHON and KWAN was higher than that in pressure between KWAN and CHUCK. The findings explain why oriental medical doctors take pulses by dividing CHON, KWAN and CHUCK in the short length of the three fingers. It can be used to develop a pulse diagnosis device enabling accurate measurement according to the characteristics of blood vessel structure based on where the pulse is taken. Furthermore, the results can be used as basic data for the development of a pulse diagnosis simulator.

• 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.

• 대한기계학회논문집B
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• 제28권12호
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• pp.1528-1534
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• 2004

The combination of ultrasound echo images with digital particle image velocimetry (DPIV) methods has resulted in a two-dimensional, two-component velocity field measurement technique appropriate for opaque flow conditions including blood flow in clinical applications. Advanced PIV processing algorithms including an iterative scheme and window offsetting were used to increase spatial resolution. The optimum concentration of the ultrasound contrast agent used for seeding was explored. Velocity validation tests in fully developed laminar pipe flow result of echo PIV showed good agreement with both optical PIV measurements and the known analytic solution based on a volume flow measurement.

• 한국의류학회지
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• 제45권3호
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• pp.495-509
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• 2021

The study investigated the effects of five commercial body shaping foundation items on clothing pressure, blood flow, body shaping effectiveness, and wearer satisfaction for middle-aged women. The study measured clothing pressure at each of the 10 designated measurement points for twelve subjects wearing the foundations. Blood flow changes were recorded and body shaping effectiveness was analyzed by comparing differences in girth when wearing and not wearing the foundations. The subjects rated wearer comfort along a 7-point Likert scale. The results were that clothing pressure was present at all measurement points, and all foundations placed the least pressure on the anterior underbust girth. In addition, clothing pressure was high in the order of the lateral, posterior, and anterior areas. As clothing pressure increased, blood flow and velocity decreased and overall wearer satisfaction was assessed to be less comfortable. Body shaping effectiveness was evident across all the items, as all decreased girth measurements significantly. In conclusion, the appropriate level of clothing pressure provided by experimental foundations which is positive for blood flow and has an excellent body shaping effect was found to be between 0.53 and 1.77 kPa.

• 대한기계학회논문집B
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• 제35권7호
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• pp.685-691
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• 2011

본 연구는 도플러 광 단층촬영법이 미세유동 및 미세구조를 동시에 측정하는 첨단 장비임을 보일뿐 아니라 기존의 도플러 광 단층촬영법의 한계를 극복한 새로운 방법을 제시하였다. 기존의 도플러 광단층촬영법은 샘플로 입사되는 광과 같은 방향의 속도성분만을 측정할 수 있다. 본 연구에서는 임의의 속도벡터의 세 성분을 동시에 측정할 수 있는 다관점 도플러 광 단층촬영법을 개발하였고 심전도 게이트를 사용하여 맥동혈류유동의 3 차원 공간 내에서 위상속도 벡터장을 측정하는 심전도 게이트 다관점 도플러 광 단층촬영법의 타당성 조사를 햄스터 모래주머니 모델을 사용하여 수행하였다. 이를 통해 측정 가능한 속도성분의 수를 증가할 뿐 아니라 프레임 레이트가 심박에 비해 상대적으로 느리기 때문에 발생하는 엘리아싱 문제를 해결하였다.

• 대한기계학회논문집B
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• 제40권8호
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• pp.511-517
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• 2016

3차원의 협착 혈관모델을 3D 프린터를 이용하여 제작하였다. 협착부는 관의 중심축에 대하여 대칭인 형태이며, 협착부가 0도인 직관과 10도로 굽어진 관인 두 가지 모델에 대하여 실험을 수행하였다. 협착모델 내부 속도장을 매질에 대한 왜곡 없이 측정하기 위하여 굴절률일치법을 이용하였다. 정량펌프를 사용하여 발생된 맥동유동은 펌프의 회전속도로 세 가지의 속도조건을 조절하였다. 비정상상태의 속도장은 time-resolved PIV 기법을 이용하여 측정되었다. 주기적인 와류의 생성과 이동은 관 내 최대속도 영역과 관련 있으며, 와류의 크기와 위치 및 대칭성은 레이놀즈수와 관의 기하학적 구조에 영향을 받음을 알 수 있었다. 곡선관에서는 협착부 하류에 재순환 영역이 관찰되며, 이는 혈류역학적 관점에서 혈전의 형성과 침착 가능성을 설명해준다.

• 대한의용생체공학회:의공학회지
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• 제41권5호
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• pp.179-184
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• 2020

Purpose: The purpose of this study was to evaluate the effect according to the NEX, VENC, targeted cardiac phases on the velocity measurement of 4D phase-contrast MRI. Materials and Methods: The abdominal aortic phantom was made to experiment. The working fluid was mixed with water and glycerin to mimic the density and viscosity of human blood. The inlet velocity was Reynolds number 2000. The experimental conditions were NEX 1 and 4, VENC 102 cm/s and 200 cm/s, and 10 and 15 targeted cardiac phases, respectively. The average flow rate, average velocity, maximum velocity, and cross-section area were measured. Results: As a result of the case-by-case comparison, the error rate was less than 5%. There was no significant difference (p > 0.05). Conclusion: It is expected that this result will be useful for acquiring blood flow information in clinical practice.