• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.7
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• pp.773-783
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• 1992

There have been several control schemes for the single input systems with unmeasurable state variables using variable structure control(VSC) theory. However, each of them is a study on the systems which can be represented in the phase canonical form or non-phase canonical form dynamic equation separately. As these control algorithms have difficulties in practical application by its theoretical limitations, in this paper we propose a new VSC theory which overcomes those limitations, in this paper we propose a new VSC theory which overcomes those limitations of proposed schemes. This new control scheme can be realized for the general linear systems which have unmeasurable state variables. And the switching function of this VSS algorithm consists of measurable state variable function(reduced-order switching function) and its derivatives. Also in the construction of control imput only measurable state variables are used.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.1
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• pp.21-26
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• 2006

In this paper, to improve the variable and remote controllable digital power-supply design. It is able to RS-232 communication for remote control. And it can also observe the correct power. Finally, it intend to high ratio design that compare input power with output power. There are especially useful solution in korea to be under the unstable voltage environment.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.688-690
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• 2005

본 논문은 2D 실사 기반 가상 헤어스타일의 자연스런 착용감을 제공하기 위한 것으로, 가상 헤어스타일러의 모발 블렌딩 방법에 관한 것이다. 제안된 방법을 2D 실사 영상에서 추출한 헤어스타일을 임의의 인물 영상의 두상에 정렬시킨 상타에서 원래의 헤어스타일에서 추출한 헤어스타일로 변해가는 반자동 필드 모핑을 수행할 시에 머리모양의 변형을 따라 단계적으로 변하는 가변 모핑 마스크를 사용하여 가상 헤어스타일을 생성하고 이렇게 생성된 헤어스타일을 가변 모핑 마스크의 경계 영역에서 시그모이드 함수에 기반한 모발 블렌딩을 수행함으로써 이중 노출 현상이 제거됨과 동시에 자연스러운 착용감을 제공하는 여러 유형의 헤어스타일을 자동으로 생성할 수 있다. 통상 이러한 작업은 사용자의 수작업에 전적으로 의존하는 반면에 제안된 방법은 반자동 필드 모핑에 기반한 편리한 사용자 인터페이스를 제공할 수 있기 때문에 반자동화를 통해 작업 피로도와 작업 시간을 경감시킬 수 있고 비숙련자도 간단한 사용자 입력을 통해 이중 노출 현상이 제거됨과 동시에 자연스런 착용감을 제공하는 가상 헤어스타일을 생성할 수 있는 이점이 있다.

• Korean Journal of Optics and Photonics
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• v.11 no.3
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• pp.166-170
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• 2000

A wavelength tunable all-optical clock recovery using a semiconductor optical amplifier in a fiber ring cavity is proposed and demonstrated at the wavelength of 1530 nm to 1570 nm. A synchronized optical pulse train is recovered from 10 Gbps and 30 Gbps randomly generated optical pulse streams with injection locking technique. Also, the system responses to the perturbation and the input average power variation are analyzed by a large-signal model based on time-domain travelling wave equation. ation.

• Proceedings of the Korea Multimedia Society Conference
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• 2004.05a
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• pp.179-182
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• 2004

무선통신분야에서 LMS5(Least Mean Square) 알고리즘은 식이 간단하고 계산량이 비교적 적기 때문에 널리 사용되고 있다. 그러나 시간영역에서 처리할 경우 입력신호의 고유치 변동폭이 넓게 분포되어 수렴속도가 저하하는 문제점이 있다. 이를 해결하기 위하여 신호를 FFT(Fast Fourier Trasnform)나 DCT(Discrete Cosine Transform)로 변환하여 신호간의 상관도를 제거함으로써 시간영역에서 LMS알고리즘을 적용할 때 보다 수렴속도를 크게 향강시킬 수 있다. 본 논문에서는 수렴속도 향상을 위해 시간영역의 적응 알고리즘을 직교변환인 고속웨이브렛(wavelet)변환을 이용하여 변환영역에서 수행하며, 짧은 필터계수를 가지는 DWT(Discrete Wavelet Transform)특성에 맞는 Fast running FIR 알고리즘을 이용하여 WTLMS(Wavelet Transform LMS)적응알고리즘을 통신시스템에 적용한다. 적응 알고리즘의 성능향상을 위하여 시간에 따라 적응상수의 크기를 가변시켜 수렴 초기에는 큰 적응상수로 따른 수렴이 가능하도록 하고 점차 적응상수의 크기를 줄여서 misadjustment도 줄이는 방법의 적응 알고리즘을 제안하였다. 제안한 알고리즘을 실제로 적응잡음제거기(adaptive noise canceler)에 적용하여 컴퓨터 시뮬레이션을 하였으며, 각 알고리즘들의 계산량, 수렴속도를 이용하여 각각 비교, 분서하여 그 성능이 우수함을 입증하였다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.2
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• pp.65-71
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• 2011

This paper shows variations on bandwidth for the 5-microstrip 4-port structure by cutting out part of 2nd and 4th line of 5 lines. In 2nd line case, the bandwidth to pass is decreased by 300MHz and one of two input ports operates in diplexer. Both of 2nd and 4th line cut takes each of two input ports as a diplexer. The bandwidth for 4th line case has almost same bandwidth for the unmodified structure, a bit wider than that of the 2nd line case. Especially the isolation between input and other out port in center frequency of stop band shows 41dB for port 1, 32dB for port 2.

• Journal of Korea Multimedia Society
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• v.2 no.1
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• pp.99-108
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• 1999

In this paper, a new robust adaptive algorithm is proposed to improve the performance of AEC without computational burden. The proposed adaptive algorithm is based on NLMS algorithm, and its step-size is varied with the reference input signal power and the desired signal power. Its step-size is normalized by the sum of the powers of the reference input signal and the desired signal. When the near-end speaker's speech and noise are applied into the microphone, the step-size becomes small and the misalignment of coefficients are reduced. The convergence speed is comparable to NLMS algorithm at AEC application because the echo signals are attenuated about 10∼20 dBSPL. The characteristics of this algorithm is also analyzed and compared with conventional ones in this paper.

• Journal of IKEEE
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• v.15 no.3
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• pp.205-210
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• 2011

A novel hysteresis tunable monolithic comparator circuit based on a 0.35 ${\mu}m$ CMOS process is suggested in this paper. To tune the threshold voltage of the hysteresis in the comparator circuit, two external digital bits are used with supply voltage of 3.3V. The threshold voltage of the suggested comparator circuit is controlled by 234mV by change of 4 digital control bits in the simulation, which is a close agreement to the analytic calculation.

• The Transactions of the Korean Institute of Power Electronics
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• v.5 no.2
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• pp.176-183
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• 2000

In this paper, sixth order hannonic injected PWM for improving‘ input CWTent distortion of single switch t three phase boost converter is presented. Peliodic sixth order hmmonic ${\gamma}$oltage is inj<:ded in the control circuit t to var${\gamma}$ the duty ratio of the converter switch within one switching cycle. In the result, the input phase c currents are forced to track the input voltage and an 해most unity power factor is obtained. Expelimental r results are verified by converter operating at 400V /6kW with three phase 140V ~220V input and by C02 arc w welding machine which was nonlinear load with 3 $\phi$ 220V input.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.10
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• pp.52-63
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• 1998

In this paper, several improvements to a copy network proposed previously for multicast packet switching are described. The improvements provide a solution to some problems inherent in multicasting. The input fairness problem caused by overf low is solved by a dynamic starting point decider(DSD), which can calculate running sums of copy requests starting from any input port. The starting point is changed adaptively in every time slot based on both the fill level of the input buffers in current time slot and the overflow situations of the previous time slot. Using the fill level of the conventional network. The DSD also provides the function of regulating overall copy requests according to the amount of input traffics. This is an essential function in improving overall throughputs of the copy networks. The throughput of a multicast switch can be improved substantially if partial service of copy request is implemented when overflow occurs. Call-splitting can also be implemented by the DSD in a straightforward manner. The hardware for the DSD is derived with the objective of simple architectures for the high speed operation. Simulation study of the copy network under various traffic conditions is presented to evaluate its performance.