• Journal of Biomedical Engineering Research
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• v.18 no.4
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• pp.485-491
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• 1997

This paper describes the relationship between skin impedance signal, behavioral signal, and subjective evaluation depending on arousal level. Nz and reaction time had similar trend with mKSS level, but eyeblink rate was different from these two parameters. eye-blink rate increased slowly from mKSS level 1 to 5, and had high increasing rate at mKSS 7. But it showed steep descent at mKSS level 9. Each subject showed different eye-blink rates, but changing rates of EBR was similar at eachm KSS level. Therefore it suggests that rising rate of EBR can be used arousal level criterion. From the result of reaction time test. human performance was decreased rapidly above the mKSS level 5, and false positive and false negative data was observed above the mKSS level 3. It is desirable to give a subject some stimuli such as sound or aroma to rise arousal level between mKSS level 3 and mKSS level 5.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.7
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• pp.1339-1342
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• 2007

In this study, we determined the optimum electrode pair for measuring the abdominal pressure using bio-impedance method and compared with conventional methods. 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 noninvasively 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.

• Journal of IKEEE
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• v.24 no.3
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• pp.713-718
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• 2020

The method of measuring skin active points is a technique for obtaining a lot of biometric information because it is measured with convenience, low cost and non-invasive methods. In this paper, we used in a three electrode measure method that has the advantage of measuring the impedance of the APs under the skin. The impedance measuring method is well illustrated by a simple model of an equivalent electrical circuit that correlates well with experimental results. The characteristic frequencies of APs are about 15-30HZ higher than that of surrounding skin and the values of measured reactance are about 35-77KΩ smaller. This technology analyzed accurately and objectively the reactance and characteristic frequency of APs and the surrounding skin using a non-invasive measuring system.

• Proceedings of the KIEE Conference
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• 2002.11c
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• pp.399-402
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• 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.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.52 no.8
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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.

• Journal of Oriental Neuropsychiatry
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• v.19 no.1
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• pp.71-81
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• 2008

Objective: Obesity threatens not only the problem of beauty but also health. Furthermore, it could be harmful a chronic disease to increase mortality rate. A purpose of this study is to show a effect of obesity control as developing a herbal medicine, Gyeongshingangjeehwan16 (GGEx16), in order to control obesity that is a harmful factor for healthy. Method : In order to prove the effect of GGEx16, BMI, fat distribution, fat control and fitness score which are closely related with obesity are considered as variables. Each variable is measured, for statistical analysis, using measurement implement of InBody 3.0 which applied a theory of bioimpedence analysis. Result and Conclusion : As a result of statistical analysis for four variables, it was improved that there are the improved effect for obesity because GGEx16 is statistically meaningful better than prior to taking.

• Journal of Biomedical Engineering Research
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• v.20 no.2
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• pp.183-190
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• 1999

The purpose of this study was to develop a portable and convenient closed-loop contrel type electrical stimulator for patients with foot drop. This system restores walking movement as well as prevents from atrophy or necrosis of lower limb muscles and increases blood circulation in hemiplegic patients caused by traffic accident, industrial disaster or stoke. This system detects the changes of the ankle joint angle during walking, and then controls the stimulus intensity automatically to maintain the programmed level of the ankle joint angle. Also, this automatic system controls the stimulus intensity which is affected by increased electrode impedance resulting from long time use. The system detects the joint angle by an optical sensor and includes modified PID control which adjusts the stimulus intensity if the joint angle deviates from the preset value. Stimulus parameters are 30~80 volt, 40 Hz, and 0.2 ms. The system was applied to five hemiplegic patients for 42 days. Duration of stimulation was 15 min/day for the first week and then the duration was gradually increased to 30, 60, 90 and 120 min/day. The muscle force was increased up to 29.7%, muscle fatigue was decreased compared with the level before stimulation and the pattern of locomotion was improved. These results suggest that the electrical stimulator with closed-loop control type is more convenient and effective in restoration of locomotion of patients with foot drop than open-loop system.

• Journal of Biomedical Engineering Research
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• v.25 no.1
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• pp.21-26
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• 2004

Recently, many people want to know their state of health, such as a body fat rate, anywhere and anytime. The Personal Digital Assistance(PDA) is the portable wireless apparatus that has become widely popular. There are many application areas of the IDA to be in mobile care devices. In this study, we developed the PDA based body fat measurement system, composed of a cradle type measurement module and a WindowCE operated software module, a regression equation for predicting lean body mass (LBM). Sixty-three weight-stable subjects (53 men, 10 women) aged 20∼32yr participated in this study. A regression model, LBM ＝ (0.0005＊Height2 - 0.0160＊Impedance ＋ 0.3920＊Weight - 0.0684＊Age - 5.8141＊Sex ＋ 25.984, was found. The correlation coefficient( r) of body fat rate between developed system and HTM1000plus(BionetTM) was 0.928. HTM1000plus is a commercially available and approved by KFDA. These results indicated that developed system is reliable for estimation of body fat rate. Although developed system is the PDA based miniaturized, it shows good performance comparing with other commercial product.

• 전자공학회논문지 IE
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• v.43 no.1
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• pp.16-24
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• 2006

This paper is aimed to develope of an integrated BCI(Brain Computer Interface System) that make possible for simultaneous multichannel data process and used extra cellular neural activity from the vestibular system instead of electroencephalogram signals for more precision control. The electrical properties pre-amplifier are 47.6 dB of gain, 0.005 % of distortion at 100 Hz, 12M$\Omega$ of input impedance. Window discriminator used two CPU with difference role to increase processing speed so that sampling frequency was 87 kHz. The designed window discriminator has more not only two times in signal resolution power but also ten times in error discrimination power than commericially available discriminator. The proposed method decreases 100 times in amount of integrated data then BCI system during 100 ms.

• Journal of Korean Academy of Nursing
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• v.39 no.5
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• pp.693-699
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• 2009

Purpose: The purpose of this study was to identify congruence between self-perception and objective status of obesity according to %Fat, and to investigate health promotion lifestyle in college women. Methods: The participants were a convenience sample of 392 college women who were eligible and agreed to participate in this study. Respondents were asked questions using a health promotion lifestyle profile and were evaluated for their body composition using InBody 3.0. The data were analyzed with SPSS 14.0 program, which was used for Chi square, ANOVA, and post-hoc comparison with Scheffe. Results: The major findings were as follows; 1) Overall, 41.8% of participants misclassified their perceived status of weight by %Fat standards and kappa was 0.329. 2) Two percent were underweight by BMI but overweight by %Fat and 39.0% normal weight by BMI but overweight by %Fat. 3) There were significant differences in health promotion lifestyle according to self-perception of body weight but there was no difference in health promotion lifestyle according to %Fat standards. Conclusion: These findings suggest the necessity for development and application of tailored health promotion program based on self-perception of body weight and %Fat in order to reform incorrect body image and health behavior in college women.