• Journal of Mechanical Science and Technology
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• 제15권12호
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• pp.1623-1629
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• 2001

This parer presents a CVT line pressure control strategy for the increased shift speed. Firstly, an algorithm to increase the CVT shift speed is suggested based on a modified CVT shift dynamics and shift speed maps are constructed. In addition, simplified dynamic models of the line pressure and the ratio control valve are derived by considering the CVT shift dynamics, and low level control algorithms for the ratio and the line pressure control are proposed. Using the shift speed maps and the simplified dynamic models of the CVT system, shift performance is investigated. It is found from the experimental and simulation results that improved shift speed can be achieved by increasing the lilly pressure.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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• pp.1002-1003
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• 2006

Power line communication: PLC which easy to install at anywhere near outlet for electric machine. PLC uses transmission line for voltage of which is 60 Hz. One of the important thing is the processes of adding signal to power line and extracting the signal from power line, another is to choose the strong modulation method which sends signals to long distance without loosing in PLC channel. but PLC channel have very high and variable noise and attenuation and then it is very hard to transmit optimally between the transmitter and the receiver. AWGN, impulse noise and attenuation are created. To overcome the noise and attenuation. Multi-carrier Modulation methods like as OFDM and DMT which divide the channel into many sub-channel are powerful communication methods for PLC. In this paper, PLC channels are simulated for getting BER by Matlab simulink

• The Journal of the Acoustical Society of Korea
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• 제20권3E호
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• pp.18-24
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• 2001

Speaking rate represents how many phonemes in speech signal have in limited time. It is various and changeable depending on the speakers and the characters of each phoneme. The preprocessing to remove the effect of variety of speaking rate is necessary before recognizing the speech in the present speech recognition systems. So if it is possible to estimate the speaking rate in advance, the performance of speech recognition can be higher. However, the conventional speech vocoder decides the transmission rate for analyzing the fixed period no regardless of the variety rate of phoneme but if the speaking rate can be estimated in advance, it is very important information of speech to use in speech coding part as well. It increases the quality of sound in vocoder as well as applies the variable transmission rate. In this paper, we propose the method for presenting the speaking rate as parameter in speech vocoder. To estimate the speaking rate, the variety of phoneme is estimated and the Line Spectrum Pairs is used to estimate it. As a result of comparing the speaking rate performance with the proposed algorithm and passivity method worked by eye, error between two methods is 5.38% about fast utterance and 1.78% about slow utterance and the accuracy between two methods is 98% about slow utterance and 94% about fast utterances in 30 dB SNR and 10 dB SNR respectively.

• 한국가축번식학회지
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• 제22권3호
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• pp.237-244
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• 1998

To investigate the fidelity of transgene transmission and expression, we produced transgenic mice carrying bovine $\beta$-casein/bovine grwoth hormone(bGH) fusion gene and examined transmission efficiency and expression level of the transgene in the founders and their progeny. The transgene was composed of 1.8 kb bovine $\beta$-casein promoter and 2.1 kb bGH gene. Ten transgenic mice were produced. Milk and mammary gland were collected from eight transgenic lines at 10-day lactation and a, pp.ied to Western and Northern blot analyses. The bGH expression was detected in four of them. The concentrations of bGH in milk were highly variable from 4$\mu\textrm{g}$/ml to 600$\mu\textrm{g}$/ml depending on the lines. The bGH mRNA level in mammary gland was closely correlated with the bGH concentration in milk in each transgenic line. These results indicated that bGH transgene expression was a, pp.opriately regulated in the mammary gland and secreted into milk in transgenic mice. By using two transgenic lines(#2, #7) secreting a considerable amoung of bGH into their milk, the inferitance and maintenance of transgenic phenotype were assessed in successive four generations. The mean transmission frequencies of transgene in lines #2 and #7 were 34% and 40%, respectively. The bGH concentration in milk were 80, 240, 120, 60$\mu\textrm{g}$/ml in each G0(generation 0), G2, G3, G4 generation of line #2 and 600, 1600, 860, 900$\mu\textrm{g}$/ml in each G1. G2, G3, G4 generation of line #7. These results demonstrated that bovine $\beta$-casein/bGH gene was stably transmitted from generation to generation in a Menelian fashion in trasgenic mice and consistenly expressed in their milk throughout the generations, although there was a little variation in the transmission frequency and expression level of the transgene between generations.

• 한국정보통신학회논문지
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• 제13권4호
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• pp.668-674
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• 2009

본 논문에서는 450kHz 이하의 저주파수 대역에서 480kbps급으로 동작하는 고속 전력선 통신 모뎀을 설계 및 구현하였다. 저주파수 대역에서의 전력선 채널모델을 검토하였으며, 협대역 채널환경 아래에서 고속의 데이터 전송을 위하여 OFDM(Orthogonal Frequency Division Multiplexing) 기법을 사용하였다. 또한 전력선 채널상태에 따라 16-QAM(Quadrature Amplitude Modulation) 또는 QPSK(Quadrature Phase Shift Keying) 변조방식으로 가변 전송함으로써 열악한 채널환경에서도 QoS를 만족할 수 있도록 설계되었다. 실험 결과, 설계된 모뎀은 신호대역폭 $50kHz{\sim}450kHz$에서 변조방식에 따라 각각 480kbps 또는 240kbps의 가변 전송률을 제공함을 확인하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.409-412
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• 2001

This paper decides provision of brightness by average value of horizontal pixel, vertical pixel association. Give weight at association value calculation to improve diagonal line characteristics, and applied method to add average of vertical pixel and average of diagonal line pixel at interpolation. Therefore it improves PSNR, and it proposed algorithm that improve horizontal outline and vortical outline characteristics in big area of luminance contrast. It changed scanning line of serial scan based on proposed algorithm and designed variable image system for efficient data transmission through PCI interface circuit.

• 조명전기설비학회논문지
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• 제16권1호
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• pp.100-105
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• 2002

본 연구에서는 FACTS 기기 중 가장 우수한 기기로서 활발히 연구가 진행되고 있는 UPFC가 송전계통에 연계되었을 경우 거리계전기가 보는 임피던스 특성을 분석하였다. 최근, 계통 안정도와 전력 전송용랑을 증가시키기 위해 UPFC가 사용됨에 따라 기존의 보호계전기에 어떠한 영향을 줄 것인가를 미리 연구하여 보호계전기가 오동작 및 부동작이 나지 않도록 대책을 강구할 필요성이 있다. UPFC가 연계되어 운전되면 송전계통의 조건이 UPFC의 운전조건에 따라 변하게 되고 송전선로 보호용으로 설치된 거리계전기가 보는 임피던스값도 영향을 받을 것이다. 따라서 UPFC가 설치된 선로에서 사고를 검출하는 거리계전기가 임피던스를 계산시 UPFC기기에 의한 보상전압 크기와 위상을 충분히 고려해서 계산되어져야 한다. 본 연구에서는 UPFC기기가 연계된 송전선로에서 사고 발생시, 거리 계전기의 오동작을 방지하기 위해 보호협조가 필요함을 제시하였으며 PSCAD/EMTDC를 통해 UPFC와 계통을 모델링하여 사고를 모의후 거리계전기가 보는 임피던스 특성을 분석하였다.

• Wind and Structures
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• 제18권3호
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• pp.235-252
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• 2014

An effective numerical technique to calculate the reactions of a multi-spanned transmission line conductor system, under arbitrary loads varying along the spans, is developed. Such variable loads are generated by High Intensity Wind (HIW) events in the form of tornadoes and downburst. First, a semi-closed form solution is derived to obtain the displacements and the reactions at the ends of each conductor span. The solution accounts for the nonlinearity of the system and the flexibility of the insulators. Second, a numerical scheme to solve the derived closed-form solution is proposed. Two conductor systems are analyzed under loads resulting from HIW events for validation of the proposed technique. Non-linear Finite Element Analyses (FEA) are also conducted for the same two systems. The responses resulting from the technique are shown to be in a very good agreement with those resulting from the FEA, which confirms the technique accuracy. Meanwhile, the semi-closed form technique shows superior efficiency in terms of the required computational time. The saving in computational time has a great advantage in predicting the response of the conductors under HIW events, since this requires a large number of analyses to cover different potential locations and sizes of those localized events.

• Journal of Electrical Engineering and Technology
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• 제10권3호
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• pp.1093-1101
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• 2015

Partial Discharge (PD) is a physical phenomenon, which causes defects and damages to the insulation. This phenomenon is regarded as the most important source of fault and defect in power transformers. Therefore, methods of high speed and precision are considered of special importance for the maintenance of transformers in localization of the origin of partial discharge. In this paper, the transformer winding is first modeled in a transient state by using RLC ladder network and multiconductor transmission line (MTL) models. The parameters of the two models were calculated by Ansoft Maxwell software, and the simulations were performed by Matlab software. Then, the PD pulses were applied to the models with different widths of pulses. With regard to the fact that the signals received after the application of PD had a variable frequency nature over time, and based on the wavelet transform and signal energy, a new method was presented for the localization of PD. Ultimately; the mentioned method was implemented on a 20 kV winding distribution transformer. Then, the performances of the models used in this paper, including RLC and MTL models, were compared in different frequency bands for the correct distinction of partial discharge location.

• 한국항공우주학회지
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• 제46권3호
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• pp.251-256
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• 2018

고속 비행체의 궤적 추적을 위하여 사용하는 레이다 중계기의 경우, 짧은 폭의 펄스를 방사한다. 이러한 신호의 위상 변위를 위하여 branch type 위상 변위기가 사용 된다. 이 변위기는 branch 전송선 끝의 가변 리액턴스를 이용하여 전송선 상의 위상을 변화 시킨다. 또한 고출력 신호의 제어가 용이하고, 리액턴스의 고장 시에도 삽입 손실이 크지 않은 장점이 있다. 이 논문에서는 $0^{\circ}$, $30^{\circ}$, $60^{\circ}$, $90^{\circ}$로 순차적으로 위상을 변위 시키는 400 W급 위상 변환기를 제작 시험 결과를 논한다.