• 대한의용생체공학회:의공학회지
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• 제31권5호
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• pp.375-384
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• 2010

The purpose of this study is to determine whether there is a correlation between the segmental bio-impedance measurement with the frequency modulations and the life-style disease of obesity. An obesity is not simply the factor for estimating the life-style disease of obesity, but also the risk factor occurring. There are many methods (BMI, WHR, Waist, CT, DEXA, BIA, etc.) for measuring a degree of obesity; the bio-impedance measurement is more economic and more effective than others. The physical examination, the blood test, the medical imaging diagnosis and the bio-impedancemeasurementswithmultiple frequencies for each body parts have been conducted for 77 people. The estimated value has been calculated through a segmental bio-impedance model based on multi-frequency that was created to reflect the highest correlation by analyzing correlation with linear regression analysis method for the measured bio-impedance and the risk factors. Then we compared with the clinical diagnosis. In case of high level cholesterol, low HDL-C and high LDL-C for life-style disease, the sensitivity is 80~100%and the specificity is 83~100%. This study has shown conclusively that bio-impedance can be a possible predictor to analyze the disease risk rate of population and individual health maintenance. And also the multi-frequency segmental bio-impedance can be used as early predictor to estimate the life-style disease of obesity.

• Korean Journal of Acupuncture
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• 제29권1호
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• pp.71-81
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• 2012

Objectives : The purpose of this paper was to suggest new diagnostic method that was to supersede the estimation of electrical properties at acupoints. Thus, we developed the multi- frequencies bioelectrical impedance measurement system so as to analyze the state of bio-ions in body fluid as body compositions, not skin impedance at acupoint. Methods : At low frequency, the current does not penetrate the cell membrane and at high frequency, the current passes through both intracellular and extracellular fluid because of the decreas of cell membrane impedance. To confirm the reflection of composition in extracellular fluid or intracellular fluid of segment such as acupoint, the system was developed to detect the acupoint potential between adjacent two points in the area of LU3, LU4 and LU9 using 5,50 and 200KHz. Results : The detected acupoint potential has been decreased according to elevation of frequency. As a result of correlation of left/right identical acupoint, we observed a high correlation of three types of acupoint potential at multi-frequencies. Moreover, we observed the low correlation at 5KHz, and that was a significant factor to be considered as unbalanced relationship of identical acupoints. Conclusions : On the basis of meridian theoretical point of view, we may infer the acupoint's physiological composition using the multi-frequencies bioelectrical impedance measurement system.

• 대한의용생체공학회:의공학회지
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• 제32권3호
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• pp.207-217
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• 2011

Electrode impedances are measured to quantitatively characterize the electrode-electrolyte or cell-electrode interfaces. In the case of high-density microelectrode arrays(MEAs) that have been developed for brainmachine interface applications, the characterization process becomes a repeating and time-consuming task; a system that can perform the measurement and analysis in an automated fashion with accuracy and speed is required. However, due to the large number of channels, parasitic capacitance and off-capacitance components of the switching system become the major factors that decreased the accuracy for the measurement of high impedance microelectrodes. Here we investigated the implementation of automatic impedance measurement system with analyzing the causes of possible measurement-related problems in multichannel switching configuration. Based on our multi-channel measurement circuit model, we suggest solutions to the problems and introduce a novel impedance measurement scheme using electro-mechanical relays. The implemented measurement system could measure |Z| < 700 $k{\Omega}$ of impedance in - 10% errors, which can be widely applicable to high density neural recording MEAs.

• 대한의용생체공학회:의공학회지
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• 제32권1호
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• pp.37-44
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• 2011

This paper describes the development and assessment of conductive fabric sensor for evaluating knee movement using bio-impedance measurement method. The proposed strip-typed conductive fabric sensor is compared with a dot-typed Ag/AgCl electrode for evaluating validity under knee movement condition. Subjects are composed of ten males($26.6{\pm}2.591$) who have not had problems on their knee. The strip-typed conductive fabric sensor is analyzed by correlation and reliability between a dot-typed Ag/AgCl electrode and the strip-typed conductive fabric sensor. The difference of bio-impedance between a dot-typed Ag/AgCl electrode and the strip-typed conductive fabric sensor averages $7.067{\pm}13.987\;{\Omega}$ As the p-value is under 0.0001 in 99% of t-distribution, the strip-typed conductive fabric sensor is correlated with a dot-typed Ag/AgCl electrode by SPSS software. The strip-typed conductive fabric sensor has reliability when it is compared with a dot-typed Ag/AgCl electrode because most of bio-impedance values are in ${\pm}1.96$ standard deviation by Bland-Altman Analysis. As a result, the strip-typed conductive fabric sensor can be used for assessing knee movement through bio-impedance measurement method as a dot-typed Ag/AgCl electrode. Futhermore, the strip-typed conductive fabric sensor is available for wearable circumstances, applications and industries in the near future.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.46-48
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• 2007

In this study, we determined the optimum electrode pair for measuring the abdominal pressure using bio-impedance method. Because impedance changes differ from a weight, a height, contractile force, volume of muscle and blood other or whatever of individuals, it was quantified using values of impedance change, correlation coefficient and SNR. Our results showed the optimum electrode pair (1, 9) which could detect impedance changes due to an increase of the intensity of the abdominal pressure. The correlation coefficient and quadratic function between the RMS values of EMG and the impedance changes were 0.87 and $y=0.0014x^2$+0.0620x+0.6958, respectively. It demonstrated that the abdominal pressure could be measured non-invasively and simply using bio-impedance method. We propose that this optimum electrode configuration would be useful for future studies involving the convenient measurement of abdominal pressure by ambulatory urodynamics monitoring study.

• 전기전자학회논문지
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• 제25권3호
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• pp.445-450
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• 2021

생체임피던스 측정법은 편리성, 저비용 및 저가의 장치를 이용하여 생체정보 획득 및 피부 병 진단 등에 사용 가능한 장치이다. 본 연구에서는 생체 삽입형으로 생체 정보를 획득하기 위해서 동물 생체 모델링을 통한 시뮬레이션 연구와 직접 제작한 건식용 금 전극을 이용하여 생체임피던스를 측정하였다. 동물 조직의 피하부위에 전극을 삽입하여 2 전극법으로 100 uA, 1-100 kHz 주파수를 인가하여 임피던스를 측정하였다. 측정결과 전극의 사이즈를 5 mm전극기준으로 7.5 mm, 10 mm전극과 비교하여 저항을 측정한 결과 5 mm 전극에서 높게 측정됨을 확인할 수 있다. 5 mm전극을 기준으로 7.5 mm 전극은 전체 주파수 범위에서 평균 1.49 %차이를 발견하였고, 10 mm 전극은 2.624 %로 임피던스가 차이남을 확인하였다. 향후, 연구결과는 생체 삽입형 심전도 센서 전극 설계 및 제작 등에 활용가치가 있을 것으로 사료된다.

• 한국산업정보학회논문지
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• 제18권6호
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• pp.9-16
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• 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.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2006년도 춘계종합학술대회
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• pp.693-696
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• 2006

본 연구에서는 생체 임피던스의 변화를 계측하여 혈류량의 변화를 추정하기 위한 시스템을 구현하였다. 구현된 시스템은 인위적인 압력을 가하여 압력의 변화에 따른 임피던스의 변화량을 측정할 수 있도록 구성하였으며, 크게 압력 측정부와 4 전극법을 이용한 임피던스 측정부로 구분할 수 있다. 압력 측정부는 반도체식 압력센서와 센서의 출력신호를 처리하기 위한 전자회로부로 구성하였고, 임피던스 측정부는 교류 정전류원 회로와 임피던스 신호의 검출을 위한 락인 증폭기로 시스템을 구성하였다. 구현된 시스템의 성능평가를 위하여 표준저항을 이용한 임피던스 측정부의 특성조사 실험을 수행 하였다. 그리고 실제 실험군을 대상으로 임피던스의 계측을 통한 혈류량 변화 추정실험을 수행하였고, 혈류량 변화와 평균 동맥압을 이용한 혈류 저항비를 추정하였다 그 결과 혈류저항비와 혈류량의 변화는 반비례관계를 명확하게 보여 주었으며, 상관분석을 수행한 결과 상관계수가 -0.96776으로 강한 음의 상관관계를 나타내었다.

• 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.

• 동력기계공학회지
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• 제13권1호
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• pp.65-71
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• 2009

To address the need for new intelligent sensing, this paper introduces nano sensors made of carbon nanotube (CNT) composites and presents their preliminary experiments. Having smart material properties such as piezoresistivity, chemical and bio selectivity, the nano composite can be used as smart electrodes of the nano sensors. The nano composite sensor can detect structural deterioration, chemical contamination and bio signal by means of its impedance measurement (resistance and capacitance). For a structural application, the change of impedance shows specific patterns depending on the structural deterioration and this characteristic is available for an in-situ multi-functional sensor, which can simultaneously detect multi symptoms of the structure. This study is anticipated to develop a new nano sensor detecting multiple symptoms in structural, chemical and bio applications with simple electric circuits.