• 센서학회지
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• 제30권4호
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• pp.196-203
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• 2021

In this study, an optical identification system was developed, wherein visible light is used to transmit the interrogating signal, and infrared is used to send the response signal. In the reader, visible light from a light emitting diode (LED) array was modulated via modified pulse width modulation for flicker-free illumination and dimming control. Moreover, the duty factor of the dimming control time was employed to control the illumination from the LED. In the transponder, the spike signal in the output of the high-pass filter was utilized to recover the interrogating signal while preventing interference from the 120-Hz noise from adjacent lighting lamps. The illumination was controlled in 26-86% range of the constant wave LED illumination by changing the duty factor from 20% to 90%. This configuration is advantageous for the construction of optical identification systems for automatic security check and car fare calculation at toll gates or parking facilities.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 C
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• pp.1631-1633
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• 2001

In manufacturing processes, various and suitable pulse shapes are required for the purpose of material processing and the pulseshape is regarded as a dominant factor due to the specific property of processing materials. Therefore, in this study, a variable pulse width, high duty cycle Pulse Forming Network(PFN) is constructed by time sequently. The power supply for this experiment consists of three switching circuits. The PFN elements operate at low voltage and drive the primary of HV leakage transformer. The secondary of the transformer has a full-wave rectifier, which passes the pulse energy to the load in a continuous sequence of properly phased and nested increments. We investigated laser pulse width as various delay time among three switching circuit. As a result, we tan obtain various laser pulse width from about 4ms to 10ms. The maximum laser pulse width obtained at this experiment was about 10ms at delay time of 4ms among each switching circuit.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 정기총회 및 추계학술대회 논문집 학회본부
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• pp.126-128
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• 1993

Rectifiers of power conversion system are widely used condenser at input to be cheap and to be simple construction. But this method is produced harmonics of pulse at peak value of input AC voltage. The main circuit which make input current of a sinusoidal wave and improve power-factor is almost taken step-up converter. This paper is able to obtain high power-factor and efficiency because the input current is made sinusoidal wave in single phase alternating current(AC) source. Also the proposed converter is able to minimize switching loss by ZVCS(zero voltage switching and zero current switching).

• Korean Journal of Acupuncture
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• 제27권1호
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• pp.13-22
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• 2010

Objectives: The information on the depth where pulse wave appears is as important as pulse waveform. The aim of this study was to classify pulse pattern using pressure-height(P-H) volume-curve by 5 applied pressure levels to find out the information on the depth of pulse and interpret the floating & sinking pulse in oriental medical pulse diagnosis. Methods: We used 3 dimensional pulse imaging analyser (DMP-3000, DAEYOMEDI Co., Korea), which measures radial pulse waveforms noninvasively by way of tonometric method at 5 applied pressure levels, and shows P-H volume-curves by applied pressure. 448 subjects were enrolled, pulse waveforms were measured and the P-H volume-curves were gained on the three locations of Chon, Kwan, and Cheok. Results: Gained P-H volume curves were classified into 3 types ; increase type, decrease type, and increase-decrease type. Increase-decrease type appeared more often on Chon and Kwan, while increase type appeared more often on Cheok. In a few cases, decrease-type appeared on Chon and Kawn, however it never appeared on Cheok. Conclusions: Through the classification of pulse by P-H volume-curve, we gained the information on the depth of pulse. We speculate the decrease type as floating pulse, the increase-decrease type as middle pulse, and the increase type as sinking pulse in oriental medical pulse diagnosis. After more researches on P-H volume-curve by applied pressure, the P-H volume-curve may be used as an important factor for pulse diagnosis.

• 센서학회지
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• 제25권2호
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• pp.138-142
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• 2016

A pulse measurement by tonometry provides useful information for diagnosis, including not only blood pressure and heart rate but also parameters for estimating a condition of the cardiovascular system. Currently, various pulse measurement devices based on the tonometry have been developed. A reliability of these devices is determined by a positioning technic between the sensor and the blood vessel and a controlling technique of the pressurization level. An angle of the sensor for the pulse measurement seems to be highly related with a measured signal, however, the objective studies for this issue have been not published. In this paper, the variation of the pulse signals by tonometry direction was experimentally assessed according to the angle of the sensor. In order for guaranteeing the repeatability of the experiment, we used a pulse generator device, which can generate human pulse signal by using silicon tube and fluid pump, and developed a structure for precise adjustment of the angle and the pressurization level of the sensor. The angle of the sensor was acquired by an inclinometer, which was attached at the opposite side of the sensor. As results, a coefficient of variation (CV) of a maximum amplitude (MA) of the pulse wave was largely increased over the angle range of $-9{\sim}9^{\circ}$. Furthermore, the changes of the pulse shape showed different aspects according to the sign of the angle tilted along the blood vessel. It is expected that the results of this study can be helpful for developing more precise pulse measurement devices based on the tonometry and applying in clinic.

• 한국인터넷방송통신학회논문지
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• 제12권2호
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• pp.145-151
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• 2012

심혈관계 질환의 발병 위험요인 분석이 가능한 맥진기는 한방 의료기기에서 대표적인 연구 분야 가운데 하나이다. 그러나 기존의 대부분의 센서 기반의 맥진기는 측정시의 맥박 박동처와 센서부의 접촉상태에 따른 편위, 검출된 파형의 부정확성 및 파형분석의 어려움 등에 있어서 문제점이 발생한다. 따라서 본 논문에는 특성 센서를 사용하지 않고 단지 맥동에 의해서 유발되는 모세관 시험액의 상태 변화를 촬영한 맥동영상을 분석하여 환자의 맥파의 측정이 가능한 맥진기를 제안한다. 제안한 방법에서는 맥동영상 분석을 위한 시약영역 추출, 이진화, 수정된 열림연산, 변위측정 등의 영상처리 방법들이 적용된다. 제안한 맥진기의 성능 평가를 위해서는 추출된 압맥파로부터 맥파분석에 필수적인 5가지 주요 특징점에 대한 추출률을 측정한 결과 성공적인 결과를 보였다.

• 대한의생명과학회지
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• 제15권1호
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• pp.9-15
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• 2009

Early age at menarche, which is indicator of early biological maturity, has been shown to be associated with increased adult body mass index. Early menarche has also been associated with many cardiovascular disease risk factors and metabolic syndrome. To evaluate the impact of menarche to cardiovascular risk factor, we assessed by age at menarche, brachial-ankle pulse wave velocity (baPWV), which represents arterial stiffness, in women with or without metabolic syndrome. The subjects recruited for this study were three hundred one women. Relatively early menarche and relatively late menarche were classified according to less than $50^{th}$ percentile for relatively early menarche, and great than the $50^{th}$ percentile for relatively late menarche. Subject were divided four group, 1) women who had not adulthood metabolic syndrome and relatively early menarche, 2) women who had not adulthood metabolic syndrome and relatively late menarche, 3) women who had adulthood metabolic syndrome and relatively early menarche, 4) women who had adulthood metabolic syndrome and relatively late menarche. Women who had a relatively early menarche with adulthood metabolic syndrome had significantly high levels of blood pressure, triglyceride, fasting insulin and homeostatic model assessment of insulin resistance (HOMA-IR) levels than women with late menarche with adulthood metabolic syndrome, and had significantly lower HDL-cholesterol levels. And also, women who underwent a relatively early menarche with metabolic syndrome had highest level of baPWV in adult. In this study we found effect of age at menarche on adulthood metabolic risk factors for cardiovascular disease (e.g., baPWV, insulin resistance, hyperlipidemia) in Korean women.

• 대한한방내과학회지
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• 제31권3호
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• pp.467-476
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• 2010

Object : The purpose of this study was to investigate the correlation of atherosclerosis risk factors and pulse wave velocity (PWV) of carotid-femoral artery with Sasang constitution. This study also aimed to investigate the relationship between PWV and risk factors of atherosclerosis, including serum cholesterol and homosisteine, hs-CRP. Methods : We enrolled 160 patients without experience strokes who visited our hospital for a medical examination from January 1, 2008 to April 30, 2010 except patients whose body constitutions were undetermined according to QSCCII. We investigated the correlation between serum cholesterol values, blood pressure, body mass index(BMI), homosistein, hs-CRP and PWV. Pearson's correlation and partial correlation analysis were applied to examine the relationship between PWV and risk factors of atherosclerosis. Result : Among the 160 subjects, 54 were Taeumin, 54 were Soyangin, and 52 were Soeumin. The prevalences of high BMI (P-value <0.01), high hs-CRP(P-value <0.05), and high PWV(P-value <0.05) of Taeumin were higher than those of the other constitutions. PWV of carotid-femoral artery was significantly different among the three constitutional groups(Taeumin: $8.12{\pm}1.64m/sec$, Soyangin: $7.48{\pm}1.16m/sec$, Soeumin: $7.49{\pm}1.12m/sec$)(P-value <0.05). This research has show a statistical significance between the average amount of carotid-femoral artery PWV that is higher in Taeumin. Age factor of Taeumin was the effective determinant of the increase of mean PWV of carotid-femoral arteries. Conclusions : There were significant differences in the prevalence of atherosclerosis according to Sasang constitution. This study showed that atherosclerosis was more prevalent in Taeumin. Therefore, according to our results, risk of atherosclerosis was higher in Taeumin than among other constitutions.

• Earthquakes and Structures
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• 제4권5호
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• pp.557-585
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• 2013

The recent huge earthquake ground motion records in Japan result in the reconsideration of seismic design forces for nuclear power stations from the view point of seismological research. In addition, the seismic design force should be defined also from the view point of structural engineering. In this paper it is shown that one of the occurrence mechanisms of such large acceleration in recent seismic records (recorded in or near massive structures and not free-field ground motions) is due to the interaction between a massive building and its surrounding soil which induces amplification of local mode in the surface soil. Furthermore on-site investigation after earthquakes in the nuclear power stations reveals some damages of soil around the building (cracks, settlement and sand boiling). The influence of plastic behavior of soil is investigated in the context of interaction between the structure and the surrounding soil. Moreover the amplification property of the surface soil is investigated from the seismic records of the Suruga-gulf earthquake in 2009 and the 2011 off the Pacific coast of Tohoku earthquake in 2011. Two methods are introduced for the analysis of the non-stationary process of ground motions. It is shown that the non-stationary Fourier spectra can detect the temporal change of frequency contents of ground motions and the displacement profile integrated from its acceleration profile is useful to evaluate the seismic behavior of the building and the surrounding soil.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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• pp.127-129
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• 1988

Square-wave current source inverter drives suffer from torque pulsation and speed variation at low speed. Attempts to minimize these problems, CSI PWM strategies have been reported. It is shown that these PWM strategies are based on unnecessarily restrictive modulation laws. In this paper, trapezoidal PWM strategy for CSI is investigated theoratically by double fourier series and we proposed Harmonic Speed ripple Factor(HSF) that is independent of motor parameters and load conditions. Speed ripple are considered in T-PWM and square wave inverter by HSF. We obtain modulation index(M) and carrier ratio (CR) for minimum speed ripple.