• Bulletin of the Korean Chemical Society
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• 제25권2호
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• pp.165-166
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• 2004

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1037-1044
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• 2007

In an attempt to determine the correlations between the input acoustic impedance and the variations of the physical characteristics of the terminal elements, a five-lobe branched tube-network is mathematically developed and experimentally simulated using a lung simulator. The model takes into account some realistic conditions such as varying cross-sectional areas, flexible wall properties and branching. The effects of airway constrictions expressed by lobe stiffness variations on the impedance are determined for a range of frequencies up to 256 Hz. It is concluded that the developed model is capable of non-invasively predicting various physiological changes in the airway passages.

• International Journal of Control, Automation, and Systems
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• 제5권5호
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• pp.601-605
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• 2007

In this paper, we propose a simple and relative electrode contact monitoring method. By exploiting the power line interference, which is regarded as one of the worst noise sources for bio-potential measurement, the relative difference in electrode impedance can be measured without a current or voltage source. Substantial benefits, including no extra circuit components, no degradation of the body potential driving circuit, and no electrical safety problem, can be achieved using this method. Furthermore, this method can be applied to multi-channel isolated bio-potential measurement systems and home health care devices under a steady measuring environment.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2009년도 정보통신설비 학술대회
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• pp.364-366
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• 2009

광 바이오 센서 시스템에서 Trans-Impedance amplifier (TIA)는 광검출기로부터 입력단으로 들어오는 미세한 전기 신호를 원하는 신호레벨까지 증폭하는 역할을 한다. TIA는 광 바이오 센서 시스템의 감도 (sensitivity)를 결정하는 매우 중요한 회로로 저잡음, 저전력, 낮은 입력 임피던스 등의 특성이 요구되어진다. 본 논문에서는 광 바이오 센서 시스템에서 요구되어 지는 저전력, 저잡음 성능을 구현하기 위하여 regulated cascode (RGC) TIA를 설계하였다. 본 연구에서는 기존 common gate (CG) 기법의 TIA에서 전류원 역할을 하는 current source를 저항으로 대체하고, local feedback stage를 이용하는 RGC TIA를 저잡음, 저전력 특성 및 회로 면적 감소의 장점을 갖도록 설계하였다.

• 한국인터넷방송통신학회논문지
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• 제13권6호
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• pp.109-114
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• 2013

낮은 저항이나 좋은 전기투과도 지점으로 알려진 생물학적 활성점(biological active points, BAP)인 BAP검출을 위한 새로운 방법으로 적응주파수추적필터와 과도이벤트검출을 기반으로 하는 생체임피던스측정시스템을 사용하는 방식에 대해 제안하였다. 이 생체임피던스장치에 다중주파수 전류주입과 전압측정 모두 표면전극을 사용하였다. 또한 마이크로컨트롤러를 통하여 적응주파수추적필터를 사용한 다중주파수요소에 의해 변조된 신호의 연속적인 복조를 처리하였다. 또한 위상공간방식의 과도이벤트검출방식이 제안된 BAP등가모델에 각주파수에 대해 적용되었다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 V
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• pp.2891-2894
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• 2003

This paper describes the possibility of analyzing gait pattern from the variation of the lower leg electrical impedance. This impedance is measured by the four-electrode method. Two current electrodes are applied to the thigh and foot., and two potential electrodes are applied to the lateral aspect. medial aspect, and posterior position of lower leg. We found the optimal electrode position for knee and ankle joint movements based on high correlation coefficient, least Interference, and maximum magnitude of impedance change. From such features of the lower leg impedance, it has been made clear that different movement patterns exhibit different impedance patterns and impedance level.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.414-417
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• 2002

This paper describes the possibility of analyzing gait pattern from the variation of the lower leg electrical impedance. This impedance is measured by the four-electrode method. Two current electrodes are applied to the thigh and foot., and two potential electrodes are applied to the lateral aspect, medial aspect, and posterior position of lower leg. We found the optimal electrode position for knee and ankle joint movements based on high correlation coefficient, least interference, and maximum magnitude of impedance change. From such features of the lower leg impedance, it has been made clear that different movement patterns exhibit different impedance patterns and impedance level.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 D
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• pp.1821-1823
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• 2006

This paper presents a development of interface device for electro-oculogram(EOG) signal and it's application to the wireless mouse of wearable PC. The interface device is composed of five bio-electrodes for detecting oculomotor motion, several band-pass filters, instrumentation amplifier and a microprocessor. we have first analyzed impedance characteristics between skin and a bio-electrode. since the impedance highly depends on human face, it's magnitude differs from person. this interface device was applied to develop a wireless mouse for wearable PC, as a Bio Machine Interface(BMI). Where in the prompt on PC monitor is controlled by only EOG signals. this system was implemented in a Head Mount Display(HMD) unit. experimental results show the accuracy of above 90%.

• Smart Structures and Systems
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• 제8권1호
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• pp.139-155
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• 2011

Polymeric thin-film assemblies whose bulk electrical conductivity and mechanical performance have been enhanced by single-walled carbon nanotubes are proposed for measuring strain and corrosion activity in metallic structural systems. Similar to the dermatological system found in animals, the proposed self-sensing thin-film assembly supports spatial strain and pH sensing via localized changes in electrical conductivity. Specifically, electrical impedance tomography (EIT) is used to create detailed mappings of film conductivity over its complete surface area using electrical measurements taken at the film boundary. While EIT is a powerful means of mapping the sensing skin's spatial response, it requires a data acquisition system capable of taking electrical impedance measurements on a large number of electrodes. A low-cost wireless impedance analyzer is proposed to fully automate EIT data acquisition. The key attribute of the device is a flexible sinusoidal waveform generator capable of generating regulated current signals with frequencies from near-DC to 20 MHz. Furthermore, a multiplexed sensing interface offers 32 addressable channels from which voltage measurements can be made. A wireless interface is included to eliminate the cumbersome wiring often required for data acquisition in a structure. The functionality of the wireless impedance analyzer is illustrated on an experimental setup with the system used for automated acquisition of electrical impedance measurements taken on the boundary of a bio-inspired sensing skin recently proposed for structural health monitoring.

• 대한전기학회논문지:시스템및제어부문D
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• 제52권8호
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• pp.506-509
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• 2003

This paper describes the possibility of analyzing gait pattern from the changes of the lower leg electrical impedance. This impedance was measured by the four-electrode method. Two current electrodes were applied to the thigh, knee, and foot., and two potential electrodes were applied to the lateral, medial, and posterior position of human leg. The correlation coefficients of the joint angle and the impedance change from human leg movement was obtained using a electrogoniometer and 4ch impedance measurement system developed in this study. We found the optimal electrode position for knee and ankle joint movements based on high correlation coefficient, least interference, and maximum magnitude of impedance change. The correlation coefficients of the ankle, knee, and the hip movements were -0.913, 0.984 and 0.823, respectively. From such features of the human leg impedance, it has been made clear that different movement patterns exhibit different impedance patterns and impedance level. This system showed feasibility that lower leg movement could be easily measured by impedance measurement system with a few skin-electrodes.