• 대한전기학회논문지:시스템및제어부문D
• /
• 제51권8호
• /
• pp.374-379
• /
• 2002

In this study, we developed a new human arm movement detection system using electrical bio-impedance method with several skin-electrodes. The correlation coefficients of the joint angle and the impedance change from human arm movement was obtained using a goniometer and impedance measurement system developed in this study. The correlation coefficients of the wrist and the elbow movements were 0.94 and -0.99, respectively. This system was applied to control a robotic arm by converting the measured impedance to joint angle to confirm the validity of the proposed system. In conclusion, we confirmed that this system can control the robotic arm according to arm movement without any limitation of movement. This system showed possibility that upper arm movement could be easily measured by impedance measurement system with a few skin-electrodes.

• 한국음향학회지
• /
• 제40권3호
• /
• pp.254-260
• /
• 2021

시료의 흡음률 측정을 위해서는 비용이 많이 드는 잔향실 혹은 저주파수에서의 측정에 한계가 있는 임피던스 튜브를 사용한다. 본 논문에서는 마이크로폰을 사용하지 않고 단지 스피커 임피던스와 이로부터 도출된 Thiele/Small 변수만을 사용하여 시료의 음향임피던스와 흡음률을 구하는 기법을 제안하였다. 스피커의 등가회로를 이용하여 이 방법의 이론을 설명하였으며, 시료의 측정을 통하여 본 방법의 유효성을 증명하였다. 본 방법은 기존에 신뢰하기 어려웠던 저주파 대역에서의 흡음률을 매우 쉽게 측정할 수 있음을 확인하였다. 본 방법의 장점과 제한사항, 그리고 응용 분야에 대해서 검토하였다.

• Journal of Electrochemical Science and Technology
• /
• 제3권4호
• /
• pp.154-158
• /
• 2012

It is generally known that electrochemical impedance spectroscopy is a powerful technique and its real-time application has been demanded for prompt observations on instantaneous electrochemical changes. Nevertheless, long measurement time and laborious analysis procedures have hindered development of it. Solving the problems, here I report of a new algorithm design for development of a real-time electrochemical impedance monitoring system, which potentially provides a guideline in developing monitoring systems of electric vehicles batteries and other electrochemical power plants. The significant progress in this report is employment of the parallel processing protocol which connects independent sub functions to successfully operate with avoiding mutual interruptions. Therefore, all the processes required to monitor electrochemical impedance changes in realtime are properly operated. To realize the conceptual scheme, a Labview program was coded with sub functions units which conduct their processes individually and only data are transferred between them through the parallel pipelines. Finally, measured impedance spectra and analysis results are displayed, which are synchronized according to the time of change.

• 한국안전학회지
• /
• 제31권6호
• /
• pp.19-24
• /
• 2016

One of key parameters on lightning protection system design of electric, information and communication system is grounding impedance. Earth impedance includes numerous information about earthing performance of grounding system. This paper suggests grounding impedance measuring device which is comprised of wideband current source, voltage and current measuring components. We used IQ Demodulation to measure more accurate phase difference of voltage and current. The range of frequency is up to 1 MHz that is IEEE defined as the range of lightning surge. We compared developed grounding impedance measuring device with existing one to test its performance, and we used grounding system while we implemented measurement and analysing by using fall of potential method IEEE Std.81 proposed.

• Korean Membrane Journal
• /
• 제6권1호
• /
• pp.1-9
• /
• 2004

The impedance and the subsequent proton conductivity of Nafion$\^$/ membranes as standard samples were measured and compared via the two-probe method and the four-probe method using the prepared impedance measurement system. The different impedance behavior for the same membrane was observed at the fully hydrated state in the Nyquist impedance plot. The effect of the humidity and the temperature on the proton conduction through a membrane was investigated and compared with two different cell configurations.

• 대한기계학회논문집A
• /
• 제26권6호
• /
• pp.1016-1025
• /
• 2002

This paper deals with the measurement of the fluid viscosity by using the torsional vibration of a circular rod excited by a torsional vibrator at one end. The effect of an adjacent viscous fluid on the torsional vibration of the rod has been studied theoretically and expressed in terms of the mechanical impedance. The theoretically-obtained trend that the mechanical impedance is proportional to the square root of the viscosity times the density of the fluid has been confirmed by the impedance measurement. The paper demonstrates that a torsionally-vibrating rod can be used as a sensor to measure the viscosity of a fluid.

• 한국전자파학회논문지
• /
• 제25권11호
• /
• pp.1156-1163
• /
• 2014

본 논문에서는 EN50289 규격에 따른 동축케이블의 전달 임피던스 측정을 이용하여 여러 가지 통신 케이블의 차폐 특성을 분석하였다. EN50289 규격에서의 전달 임피던스 측정 방법은 CENELEC(European Committee For Electrotechnical Standardization)에서 규정한 Triaxial 방법이며, IEC Standard 96-1에서 규정한 Triaxial 방법과 달리 측정하고자 하는 동축케이블과 외부 도체의 직경에 관계없이 동축케이블의 전달 임피던스를 측정할 수 있는 장점이 있다. 본 논문에서는 EN50289 규격에 따른 동축케이블의 전달 임피던스 측정장치를 설계/제작하였으며, 이것을 이용한 실험 결과를 통해 측정 시스템의 신뢰할만한 주파수 대역을 결정하였고, 동축케이블의 쉴딩 기법의 차이에서 오는 영향에 대하여 분석하였다. 전달 임피던스 측정 결과, 케이블의 쉴딩 기법에 따라 전달 임피던스의 상당한 차이가 있음을 보였다. 또한, RG-58 통신용 케이블의 전달 임피던스 이론식에 의한 계산값과 측정값의 비교를 통하여 측정된 데이터가 유효함을 보였다.

• 한국전자파학회논문지
• /
• 제23권11호
• /
• pp.1315-1322
• /
• 2012

주파수 영역 반사 진단법은 케이블의 임피던스 값을 측정하여 케이블의 고장점 위치를 진단한다. 전력 케이블 진단과 같이 험한 환경 또는 활성 상태에서의 진단을 위해서는 회로망 분석기보다 오실로스코프를 이용한 시간 영역 임피던스 측정이 널리 사용되고 있다. 그러나 시간 영역에서 임피던스 측정은 주파수가 증가하면 각종 기생 성분에 의해 임피던스 오차가 증가하여, 고장점 진단의 정밀도가 떨어진다. 본 논문에서는 시간 영역 임피던스 측정에 연산증폭기를 이용한 측정 시스템을 구현하고, 오차 보정 방법을 도입하여 좀 더 광대역에서 정확한 시간 영역 임피던스 측정을 수행하는 방법을 제시하고, 실제 케이블 측정 결과를 비교하여 제안된 방법을 검증한다.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2001년도 하계종합학술대회 논문집(1)
• /
• pp.37-40
• /
• 2001

Subject of this paper is analysis of channel noise and impedance characteristics for high speed power line communication to concerned noise of transmission line and impedance in the frequency range up to 30MHz. Parameters of transmission line was inducted from experimentally power line channel measurement. Moreover, Analysis of compared based on measurement of channel characters with simulation test for appear characters.

• 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.