• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2008년도 추계학술대회 논문집
• /
• pp.145-146
• /
• 2008

• 대한한의진단학회지
• /
• 제12권1호
• /
• pp.1-12
• /
• 2008

Object: The purpose of this study is to the review recent 20 years chinese achievements on the use of impedance cardiography for chinese medicine. Methods: From the China Journal Full Text Database we searched papers on the use of impedance cardiography for chinese medicine by the keyword "심조항도(心阻抗圖)". Results: The researches are summarized into 3 parts. (1) the researches on the relationship between the parameters of impedance cardiography and the chinese medical diagnoses; pulse diagnosis and tongue inspection. (2) the researches on the objective assessment using impedance cardiography for the effects of chinese medical therapy. (3) the researches on the objective evaluation index of Heart Deficiency Syndrome using impedance cardiography. Conclusion: The parameters of impedance cardiography has been established for its usefulness in various chinese medical researches.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2002년도 합동 추계학술대회 논문집 정보 및 제어부문
• /
• pp.399-402
• /
• 2002

In this study, we constructed a four-channel impedance measurement system including a two-channel goniometer to analyze human arm movement. Impedances and joint angles were simultaneously measured for wrist and elbow movements. As the impedance changes resulting from wrist and elbow movements depended heavily on electrode placement, we determined the optimal electrode configurations for those movements by searching for high correlation coefficients, large impedance changes, and minimum interferences in ten subjects (age: 29+6). Our optimal electrode configurations showed very strong relationships between the wrist joint angle and forearm impedance (correlation coefficient = 0.95+0.04), and between the elbow joint angle and upper arm impedance (correlation coefficient = -0.98+0.02). Although the measured impedances changes of the wrist (1.1+1.5 ohm) and elbow (-5.0+2.9 ohm) varied among individuals, the reproducibilities of wrist and elbow impedance changes of five subjects were 5.8+1.8 % and 4.6+1.4 % for the optimal electrode pairs, respectively. We propose that this optimal electrode configuration would be useful for future studies involving the measurement of accurate arm movements by impedance method.

• 한국전자파학회:학술대회논문집
• /
• 한국전자파학회 2005년도 종합학술발표회 논문집 Vol.15 No.1
• /
• pp.353-356
• /
• 2005

There have been many researches on the antenna performance degradation with the presence of the human body around the antenna structure to accomodate personal communication service [1][2]. To better understand the human body effects on the antenna resonance, radiation pattern, and input impedance, simulation was carried out with changing of the distance between antenna and lossy material. Effects on the antenna performance by the surrounding materials are also important in the case of the RFID system. It is desirable that the tag antennas for RFID system must reveal isotropic radiation pattern as well as attain the good impedance matching. In this paper, we investigated the antenna resonance and input impedance characteristic when there exist a lossy material sphere near various types of antenna at 900 MHz. In short antenna resonance was mostly affected by lossy material in the case of a rectangular loop antenna, and impedance variation was smallest in the case of a halfwave dipole.

• 대한전기학회논문지:시스템및제어부문D
• /
• 제49권2호
• /
• pp.74-80
• /
• 2000

In this paper, we present a control method of mobile power assist systems. Most of mobile power assist systems have a heavy base for preventing easy tumbling, so continual movement of the base during operations causes high energy consumption and gives the high risk of human injury. Furthermore, the slow dynamics of the base limits the frequency bandwidth of the whole system. Thus we propose a cooperation control method of the mobile base and manipulator, which removes the unnecessary movements of the base. In our scheme, the mobile base does not move until the center of gravity(C.G) of the system goes outside a safety region. When C.G. reaches the boundary of the safety region, the base starts moving to recover the manipulator's initial configuration. By varying the parameters of a human impedance controller, the operator is warned by a force feedback that C.G. is on the marginal safety region. Our scheme is implemented by assigning a nonlinear mass-damper-spring impedance to the tip of the manipulator. Our scheme is implemented by a nonlinear mass-spring impedance to the tip of the manipulator. The experimental results show the efficacy of the proposed control method.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
• /
• pp.1289-1292
• /
• 1997

Typical biomechanical system such as human body and mammals possess abundant muscles which are more than required for motion generation of such systems. We have shown that the excess number of muscles play important roles in spring-like impedance modulation. redundant kinematic structure, which is another feature of biomechanical systems, allows modulations of inertia and damping properties of such systems. In this work, we propose a frequency modulation algorithm which combines the spring-like impedance with inertia impedance. also, a load distribution method for frequency modulation is also introduced. The frequency modulation represents a simulataneous control of force and kinematic redundancies, which has not been addressed in the literature.

• 한국소음진동공학회논문집
• /
• 제13권9호
• /
• pp.713-719
• /
• 2003

This paper introduces attempts to obtain the ‘representative’ characteristics of the mechanical impedance of seated Korean subjects under vertical vibration. Individual responses of driving-point mechanical impedance obtained from forty one Korean subjects are illustrated. Four kinds of vibration levels and three different sitting postures are selected to collect the responses of each subject. Those individual responses are used to estimate the ‘mean’ mechanical impedance, which may be expected to be a representative model to Korean subjects. Several interesting features of the estimated mechanical impedance are suggested and compared to those of ISO/DIS 5982.

• 한국산업정보학회논문지
• /
• 제18권6호
• /
• pp.9-16
• /
• 2013

생체임피던스 측정 시스템은 비침습적이고, 환자의 수분함량을 쉽게 측정할 수 있게 한다. 생체임피던스 측정에서 정확하고 재현성 있는 결과를 얻기 위해서는 측정조건과 하드웨어 사양의 선택 및 구성이 매우 중요하다. 본 연구에서는 1kHz에서 100kHz 주파수 범위에서 락인엠프, 랩뷰 제어시스템을 이용하여 사지와 흉부에 대해 생체임피던스 측정을 각각 수행하였으며, 측정 및 모의실험 결과를 통해 제안한 모델의 파라메터와 인가 전원의 주파수에 따른 저항 및 리액턴스 변화가 인체실험 결과와 유사한 결과로 나타남을 확인하였다. 제안한 실시간 생체임피던스 측정 시스템은 높은 신뢰성을 가지며, 인체에 대한 임피던스의 임상적인 특성 연구에도 적용될 수 있을 것이다.

• 전력전자학회논문지
• /
• 제13권1호
• /
• pp.46-54
• /
• 2008

본 논문에서는 연료전지나 배터리 및 슈퍼커패시터 등의 전기화학적 전력기기의 임피던스 모델링에 적합한 저가의 임피던스 분광 시스템을 설계하고 구현하였다. 제안된 시스템은 간단한 센서회로 및 상용 DAQ(Data Acquisition) Board와 강력한 HMI(Human-Machine Interface)를 지원하는 그래픽 언어인 LabVIEW 소프트웨어를 이용하여 구성되었고 고가의 EIS(Electrochemical Impedance Spectroscopy) 장비를 대체하여 널리 사용될 수 있을 것으로 기대된다. 또한, 제안된 시스템에서는 Lock-in Amplifier를 이용함으로써 노이즈(Noise)가 많은 환경에서도 측정 주파수 성분의 정확한 측정이 가능하게 하였다. 제안된 시스템을 이용하여 Ballard Nexa 1.2kW PEM 연료전지 스택의 주파수별 임피던스를 측정하였고, 이를 바탕으로 한 등가 임피던스 모델도 제안된다. 제시된 모델과 개발된 장비의 유용함은 리플전류에 의한 연료전지 스택의 교류 손실 측정을 통해 증명된다.

• 한국멀티미디어학회논문지
• /
• 제19권7호
• /
• pp.1146-1153
• /
• 2016

The bioelectrical impedance (BI) at the inner forearms was measured using bioelectrical impedance measurement system (BIMS), which employs the multi-frequency and the two-electrode method. Experiments were performed as follows. First, while applying a constant alternating current of 800A to the inner region of the forearms, BI (Z) was measured at nineteen frequencies ranging from 5 to 500 kHz. The prediction marker (PM) was calculated for right and left forearm. The resistance (R) and the reactance (X_c) were simultaneously measured during impedance measurement. Second, a Cole-Cole plot (relationship between reactance and resistance) was obtained for left and right forearm, indicating the different characteristic frequencies (f_c). Third, the phase angle was obtained, indicating strong dependence on the applied frequency.