• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.202-207
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• 2002

This paper deals with a novel shunted actuator, which has a capability to suppress multi-mode vibration amplitudes by using a pair of piezoceramic patches. In order to describe the characteristic behaviors of shunted dampers connected with a series and a parallel resistor-negative capacitive branch circuit, the stiffness ratio and loss factor with respect to the non-dimensional frequency are considered. To obtain a guideline model of a piezo/beam system connected with a series and a parallel resistor-negative capacitor branch circuit, the governing equations of motion is derived through Hamiltons principle and a piezo sensor equation as well as a shunt damping matrix is developed. The theoretical analysis shows that the shunted actuator developed in this study can significantly reduce multiple-mode vibration amplitudes simultaneously over the whole structural frequency range.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 추계학술대회 논문집
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• pp.792-798
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• 2012

This study shows the vibration characteristics of an actuator with six wire-suspensions, used in optical pickups of optical disc drives (ODDs). In this paper, the vibration characteristics of this beam structure is induced mathematically. To obtain vibration modes of focusing direction, the vibration analysis is achieved in lateral and longitudinal directions of the structure. The accuracy of induced vibration characteristics is proved by comparing mode frequencies with a finite element analysis. Finally, it is shown that mode shapes can be modified by changing design parameters in mathematical expressions.

• 한국소음진동공학회논문집
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• 제22권11호
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• pp.1128-1136
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• 2012

This paper analyzes the vibration characteristics of an optical pickup actuator, which has six wire-suspensions and is used in optical disc drives(ODDs). The vibration characteristics of the actuator is mathematically described by analyzing its beam configuration and motion condition confined to lateral and longitudinal directions of the beams. The accuracy of the vibration characteristics is proved by comparing mode frequencies with a finite element analysis. Finally, it is shown that mode frequencies and shapes can be modified by changing design parameters in mathematical expressions.

• 한국인터넷방송통신학회논문지
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• 제13권5호
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• pp.49-54
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• 2013

1.25Gbps PON(Passive Optical Network)용 버스트 모드 광 수신기를 설계하고 $0.8{\mu}m$ BiCMOS공정을 사용해 제작하였다. 지수함수 증폭기를 이용하여 AGC(Automatic Gain Control) 신호 생성 소요 시간을 단축시켜 버스트 앞부분의 데이터 손실을 최소화하였다. 측정결과 버스트 모드 광 수신기의 AGC 기능은 정상적으로 잘 동작하고 특성도 양호함을 확인하였다. 한편, 아이패턴의 아이는 열려있기는 하나 심한 파형 왜곡이 있고, 이로 인해 지터 특성 저하되고 있었다.

• 대한전자공학회논문지
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• 제22권6호
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• pp.46-52
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• 1985

본 논문은 구형 마이크로스트립 안테나의 H-plane 상호결합에 관한 연구이다. 두 안테나의 상호결합을 계산하기 위해서 단일 마이크로스트립 패치의 교사저항을 구하였으며 결합된 전송선로를 even mode와 add mode로 분발하여 각 mode의 특성저항와 실효 유전률을 계산하였다. 이로부터 자계적으로 결합된 안테나를 S-band 주파수에서 S-parameter를 구한 결과 이론치와 실험치가 거의 일치함을 확인할 수 있었다.

• Structural Engineering and Mechanics
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• 제8권2호
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• pp.181-191
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• 1999

This paper presents an investigation of the mode localization and frequency loci veering phenomena in an aircraft with disordered external stores. Two theoretical analyses are carried out to study the occurring mechanism of the two phenomena: condensation technique in the subspace spanned by modes of interest and geometric mapping theory in the complex plane. Two simple criteria for predicting the occurrence of the mode localization and frequency loci veering are put forward. The prediction of the phenomena by our theoretically proposed criteria is in good agreement with that obtained through numerical calculations of characteristic solutions of the disordered system.

• 전기학회논문지
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• 제56권5호
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• pp.898-904
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• 2007

This paper presents the generalized and explicit expressions for evaluating the performance of the multi-phase interleaved boost converter (IBC) operating in discontinuous inductor current mode (DICM). The full order averaged model is derived. The generalized transfer functions of interest are presented and the dynamic characteristics are analyzed. The generalized analysis of converter performance is verified through the experimental and simulation results.

• The Journal of the Acoustical Society of Korea
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• 제16권3E호
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• pp.7-13
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• 1997

This paper addresses traffic prediction issues on MPEG. A new adaptive traffic prediction scheme is proposed using MPEG picture characteristic that picture traffic depends on the coding mode of that picture, that is, I, P, and B mode. Our prediction scheme, which is based n picture decomposition (PD) and the cross-correlation of the different types of pictures, has better performance in predicting bursty MPEG traffic than that of the first-order autoregressive (AR) prediction scheme. Our simulation results show that the performance is further improved about 15% by utilizing the cross-correlations between pictures.

• 한국초전도ㆍ저온공학회논문지
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• 제4권1호
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• pp.66-72
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• 2002

This paper describes numerical modeling for thermal characteristic of vapor-cooled current leads under pulse operation. The transient thermal analysis considers the temperature difference between a helium gas (low and a copper lead and temperature dependent properties of helium gas, copper and stainless steel. This numerical modeling was compensated and validated by an experiment with commercially available 100 A vapor-cooled current leads. A proper overloading factor was suggested for the current leads under pulse operation through this modeling, which can significantly reduce heat input to a cryostat.

• 전자공학회논문지A
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• 제31A권10호
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• pp.39-47
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• 1994

In this paper, by modeling the Multilayer-Multiconductor Transmission Line(MMTL) with the characteristic parameters-effective dielectric constant, eigen modal voltages, characteristic impedances at each mode, pulse propagation characteristics of MMTL network are simulated. Transmission line modelling is performed in frequency domain, then time domain resposes are obtained by transforming the frequency domain response using fast Fourier transform.