• 전기전자학회논문지
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• 제12권3호
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• pp.172-175
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• 2008

An improved triangular/square-wave VCO using OTAs is presented. It consists of two OTAs, a timing capacitor, and a resistor. A prototype circuit built with commercially available components exhibits less than 0.01% nonlinearity in its current-to-frequency transfer characteristic from 0.2 to 14 kHz and 450 ppm/$^{\circ}C$ temperature coefficient of frequency over $-20^{\circ}C$ to $40^{\circ}$.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집E
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• pp.75-80
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• 2001

The present article deals with the numerical calculations for the inter-spray impingement of two diesel sprays under the conditions of high injection pressure. The Wave model involving the cavitation effect inside the nozzle was used for describing the atomization process. In particular, a hybrid model for drop collision was newly suggested in this study and compared with the O'Rourk's model, which has been widely used for diesel sprays. The impingement angles of 60 and 90 degrees were considered for simulation of non-evaporative diesel sprays. The calculated results for tip penetration were compared with experimental data and the Sauter Mean Diameter(SMD) characteristic was analyzed. It was concluded that the hybrid model slightly shows better agreement with experimental data than the O'Rourke's model. However, the more elaborate study should be needed for better understanding of spray-to-spray impingement phenomena.

• JSTS:Journal of Semiconductor Technology and Science
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• 제12권3호
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• pp.255-265
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• 2012

This paper presents a 15-GHz multiphase rotary traveling-wave voltage-controlled oscillator (RTW VCO) where a shielded coplanar stripline (CPS) is exploited to provide better shielding protection and lower phase noise at a moderate cost of characteristic impedance and power consumption. Test chips were implemented in a standard 90-nm CMOS process, demonstrating the measured results of 2-GHz frequency tuning range, -11.3-dBm output power, -109.6-dBc/Hz phase noise at 1-MHz offset, and 2-ps RMS clock jitter at 15 GHz. The chip core occupies the area of $0.2mm^2$ and dissipates 12 mW from a single 1.2-V supply.

• 소음진동
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• 제4권3호
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• pp.295-305
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• 1994

The reflection coefficient of a material at oblique incidence is measured in a free field. The sound pressure distributions are measured at discrete points on two measurement lines and then decomposed into plane wave components by using spatial Fourier transform. The inciedent and reflected plane wave components are obtained from a set of "decomposition equations" of which uses the plane wave propagation theory. Numerical simulations and experiments have been performed to see the effect of finite size of measurement area. To reduce this effect, a window fuction has been performed to see the effects of finite size of mesurement area. To reduce this effect, a window function has been proposed and its effect on the measurement of sound absorbing material property has been studied as well. The reflection coefficient obtained by this method is compared with those obtained from other methods; 2-microphone method in a duct and an expirical equation of which determines the characteristic impedance .rho.c and propagation constant k of a material from flow resistance information.formation.

• 대한의용생체공학회:의공학회지
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• 제14권1호
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• pp.73-80
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• 1993

This paper describes the implementation of a computerized radial pulse diagnosis by Elds of a clinical expert. On this base, we composed of the radial pulse diagnosis system in korean traditional medicine. The system composed of a radial pulse wave detection system and a radial pulse diag nosis system. With a detection system, we detected Inyoung and Cheongu radial pulse wave and processed It. Then, we have got the characteristic parameters of radial pulse wave and also quantified thats according to the method of Inyoung-Cheongu Comparison Radial Pulse Diagnosis. We defined the jugement standard of radial Pulse diagnosis system and then we confirmed the PossibiliLy for realization of automatic radial Pulse diagnosis in korean traditional medicine.

• 대한의용생체공학회:의공학회지
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• 제7권2호
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• pp.147-150
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• 1986

This paper describes the implementation of a computerized radial pulse diagnosis by aids of a clinical expert. On this base, we composed of the radial pulse diagnosis system in korean traditional medicine. The system composed of a radial pulse wave detection system and a radial pulse diagnosis system. With a detection system, we detected Inyoung and Cheongu radial pulse wave and processed it. Then, we have got the characteristic parameters of radial pulse wave and also quantified that according to the method of Inyoung-Cheongu Comparison Radial Pulse Diagnosis. We defined the jugement standard of radial pulse diagnosis system and then we confirmed the possibility for realization of automatic radial pulse diagnosis in korean traditional medicine.

• 한국멀티미디어학회논문지
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• 제14권9호
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• pp.1202-1209
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• 2011

Neuro feedback training using ElectroEncephalo Grams (EEGs) is commonly utilized in the treatment of Alzheimer's disease, and Attention Deficit Hyperactivity Disorder (ADHD). Recently, BCI (Brain-computer Interface) contents have developed, not for the purpose of treatment, but for concentration improvement or brain relaxation training. However, as each user has different wave forms, it is hard to develop contents controlled by such different wave. Therefore, an EEG process that allows the ability to transform the variety of wave forms into one standard signal and use it without taking a user's characteristic of EEG into account, is required. In this paper, a framework that can reduce users' characteristics by normalizing and converting measured EEGs is proposed for contents. This framework also contains the process that controls different brainwave measuring devices. In experiment a handling process applying the proposed framework to the developed BCI contents is introduced.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2000년도 춘계종합학술대회
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• pp.195-198
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• 2000

본 논문에서는 근거리 차량간통신(IVC)에서 DS-CDMA/QPSK 시스템의 성능을 분석하고 다중접속에 강한 장점을 지닌 60GHz 밀리미터파를 이용하여 첨단차량도로시스템(AVHS)의 플래툰주행에 적합한 One-Ray Rician 채널 모델에서의 패킷오율을 구하였다. 성능 개선 기법으로는 BCH 채널 부호화(255, 247, 1)와 MRC 다이버시티 수신기법을 동시에 채용했을 때 One-Ray Rician 페이딩 환경하에서 Rician 심도와 사용자 수의 변화에 따른 시스템의 오율 특성을 분석하고 차량간 거리에 따른 패킷 오율을 구하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.71-77
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• 2000

An axisymmetric supersonic jet is simulated at a Mach number of 1.5 and a Reynolds number of $10^5$ to identify the mechanism of sound radiation from the jet. The present simulation is performed based on the high-order accuracy and high-resolution ENO(Essentially Non-Oscillatory) schemes to capture the time-dependent flow structure representing the sound source. In this simulation, optimum expansion jet is selected as a target, where the pressure at nozzle exit is equal to that of the ambient pressure, to see pure shear layer growth without effect of change in jet cross section due to expansion or shock wave generated at nozzle exit. Shock waves are generated near vortex rings, and discernible pressure waves called Mach wave are radiated in the downstream direction with an angle from the jet axis, which is characteristic of high speed jet noise. Furthermore, vortex roll-up phenomena are observed through the visualization of vorticity contours.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.856-857
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• 2008

Wave power generation as an environmentally -friendly energy has received the attention. In this paper, therefore, the tubular type Permanent Magnet Linear Synchronous Generator (PMLSG) is proposed for wave power generation. The characteristics of tubular type PMLSG are investigated by analysis using a Finite Element Analysis (FEA). Moreover, the operating performance of generator under no-load and load with variable resistance is examined. And Taguchi method is applied for considering tolerance in manufacture. The results of FEA show that proposed tubular type PMLSG is a useful solution for small-scale wave power generation.