• Journal of Electrical Engineering and Technology
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• 제3권3호
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• pp.444-449
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• 2008

This study aims at compensation of the skin moisture level using skin impedance and SR factor. SR factor is related with the current diffusion into the skin layer. To efficiently analyze the current diffusion on the skin model, we used an electromagnetic simulation program called Ansys 10.0 Emag. We confirmed that the measured value decreases as the electric current gets more diffused to the layer below the horny layer. In order to conduct actual experiments based on the simulated result, we manufactured special electrodes with 24 pins by arranging 0.8mm-diameter electrodes every 0.5mm, in a $3{\times}8$ array. By simultaneously achieving both impedance value and SR value of skin with the manufactured electrodes, we compared the skin moisture level using the existing equipment to the skin moisture level applied using the skin impedance as well as the SR factor developed in this study. The correlation coefficient between the skin moisture level achieved from the existing equipment and the reference value was 0.615 (p<0.01), whereas the correlation coefficient between the skin moisture achieved from the regression equation in this study was 0.677 (p<0.01). Accordingly, it was confirmed that applying SR factor additionally improves the moisture level more precisely.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1991년도 추계학술대회
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• pp.98-100
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• 1991

We studied the characteristics of the compound electrode and found that the compound electrode provides the four-electrode method in a compact form. We developed a new method of measuring the skin impedance using simple electrodes at low frequencies. At high frequencies where the effect of internal tissue impedance is not negligible, we used the compensation method using compound electrodes since they measure the voltage right under the skin. At 50 kHz, we measured the real part of the skin impedance of less than $80\;{\Omega}$ on the thorax.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.1194-1197
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• 2004

High temporal-resolution and accurate measurement of skin impedance locus provides useful data for the identification of the physiological/psychological changes and also the identification of acupuncture point. An impedance spectroscopy method using digitally constructed current waveform consisting of many frequency components (multiples of 1Hz) was reported3. The time resolution of the method depends on the lowest frequency used in the waveform construction, and therefore, the measurement would be faster if the lowest frequency is the higher. However, it was not clear that how many and how low frequencies must be used for the estimation of the skin impedance parameters from which the impedance locus can be drawn. This study shows the relationship between the estimation error of the impedance parameters and the frequency coverage of the spectroscopy. The results of this study are expected to serve as the reference of the frequency selection in the impedance spectroscopy.

• 대한의용생체공학회:의공학회지
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• 제13권1호
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• pp.47-54
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• 1992

We studied the characteristics of the compound electrode and found that the compound electrode provides the four-electrode method in a compact form. We developed a new method of measuring the skin impedance using simple electrodes at low frequencies. At high frequencies where the effect of internal tissue impedance is not negligible, we used the compensation method using compound electrodes since they measure the voltage right under the skin. At 50 kHz, we measured the real part of the skin impedance of less than $80{\Omega}$ on the thorax. We propose a simple instrument which can measure accurate skin impedance at various frequencies.

• 한국멀티미디어학회논문지
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• 제20권3호
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• pp.482-490
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• 2017

Early detection of infiltration is one of the most important tasks of nurses to minimize skin damage due to infiltration. For subjects receiving invasive intravenous treatment, the bioelectrical impedance (impedance) were measured in the frequency range of 5 to 500 kHz using bioelectrical impedance spectroscopy (BIS). After attaching electrodes at both ends of a transparent dressing mounted on the skin in which IV solution was infused into the vein, the change in impedance was measured as a function of time and frequency before and after infiltration. The experimental results are described as follows. When IV solution was properly infused into the vein, the impedance was nearly constant over time and decreased with increasing frequency. However, when infiltration occurred, the impedance decreased significantly and thereafter gradually decreased with time. In addition, impedance decreased with time for all applied frequencies. In this study, when IV solution penetrated into the surrounding skin and subcutaneous tissue by infiltration, impedance was quantitatively analyzed for as a function of time and frequency. This suggests a method for early detection of infiltration using BIS.

• Biomolecules & Therapeutics
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• 제19권1호
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• pp.109-117
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• 2011

In this work, we have investigated the effect of polyoxyethylene alkyl ester nonionic surfactants on percutaneous permeation enhancement of a model drug, ketoprofen. We also investigated the mechanism involved in the enhancement using impedance and solubility measurement. Three groups of nonionic surfactants with different ethylene oxide content were studied. The permeation results showed that all surfactants enhanced the percutaneous absorption, irrespective of the molecular weight. The permeation results from PEG-45 monostearate (PEGMS45) were rather unexpected. Impedance and solubility results indicate that the mechanism involved in the enhancement of permeation by PEG-10 monooleate (PEGMO10) and PEGMS45 is rather different. The results from PEGMS45 suggest that it could be a potential candidate as a skin penetration enhancer with high molecular weight, which may poses less skin irritation and systemic side effect than the smaller surfactant molecules. Overall, this work provided some useful information on percutaneous transport enhancement and the mechanistic insights involved in skin permeation for these nonionic surfactants.

• Smart Structures and Systems
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• 제28권6호
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• pp.761-777
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• 2021

This study presents a numerical investigation on the sensitivity of electromechanical (EM) impedance responses to inner damaged concrete of a prestressed anchorage zone. Firstly, the Ottosen yield criterion is selected to simulate the plasticity behavior of the concrete anchorage zone under the compressive loading. Secondly, several overloading cases are selected to analyze inner damage formations in the concrete of the anchorage zone. Using a finite element (FE) model of the anchorage zone, the relationship between applied forces and stresses is analyzed to illustrate inner plasticity regions in concrete induced by the overloading. Thirdly, EM impedance responses of surface-mounted PZT (lead-zirconate-titanate) sensors are numerically acquired before and after concrete damage occurrence in the anchorage zone. The variation of impedance responses is estimated using the RMSD (root-mean-square-deviation) damage metric to quantify the sensitivity of the signals to inner damaged concrete. Lastly, a novel PZT skin, which can measure impedance signatures in predetermined frequency ranges, is designed for the anchorage zone to sensitively monitor the EM impedance signals of the inner damaged concrete. The feasibility of the proposed method is numerically evaluated for a series of damage cases of the anchorage zone. The results reveal that the proposed impedance-based method is promising for monitoring inner damaged concrete in anchorage zones.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 2001년도 The Seoul International Simulation Conference
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• pp.255-259
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• 2001

A skin tissue system is considered, whose configuration is electrically modelled by a layer over the infinite half space. The problem is to estimate the layer\`s thickness and respective conductivity from the measured impedance between the electrodes placed on the skin surface. A simulation is taken place as the optimization problem which is to minimize the norm between the \"measured\" and the solution for the assumed parameters.arameters.

• 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.

• 한국컴퓨터산업학회논문지
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• 제7권5호
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• pp.563-572
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• 2006

피부를 통한 최적의 광투과 치료방식은 국소병변에 직접적으로 광을 조사할 수 있는 장점을 가지나 피부의 가장 바깥 부분인 각질부의 다양한 피부색상으로 인해 광전달 능력에 차이가 있고 다양한 환자에 따라 치료가 부적절 할 수가 있다. 본 연구에서는 피부 임피이던스에 따른 광조사 방식에 따른 일정한 측정을 하기 위해 피부 임피이던스 방식과 피부영역 추출을 통해 색상정보와 차영상을 이용한 방법 즉, 색상정보를 이용한 HIS와 YIQ의 성분이 가장 보편적인데 실험에서는 피부색상에 해당하는 각 색상성분을 탐색한 다음, 색상정보를 이용한 결과로 환자의 피부모델 영역검출에 따라 결과를 영상정보를 통해 개개인의 피부모델을 자동적으로 생성, 측정하여 피부색깔, 에너지, 파장, 폭, 조사시간, 펄스지연 등을 추출하여 원하는 최적의 모델과 특성을 조사하며, 피부 임피이던스에 따른 병변치료 펄스모델링의 기준을 구하였고, 피부부하에 따른 최적의 광조사 펄스모델링 시스템을 설계하여 제작하여, 피부칼라에 따른 적절한 치료펄스 데이터베이스를 구축하였다.