• The Transactions of the Korean Institute of Electrical Engineers P
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• v.57 no.3
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• pp.255-259
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• 2008

In this paper, a current-mode integrator for low-voltage, low-power analog integrated circuits is presented. Using the proposed current-mode integrator, the baseband analog filter is designed for WCDMA wireless communication. To verify the proposed current-mode integrator circuit, Hspice simulation using 1.8V TSMC $0.18{\mu}m$ CMOS parameter is performed and achieved 44.9dB gain, 15.7MHz unity gain frequency. The described 3rd-order current-mode baseband analog filter is composed of the proposed current-mode integrator, and SFG(Signal Flow Graph) method is used to realize the baseband filter. The simulated results show 2.12MHz cutoff frequency which is suitable for WCDMA baseband block.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.57 no.3
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• pp.260-264
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• 2008

In this paper, a dual mode baseband analog channel selection filter is described which is designed for the Bluetooth and WCDMA wireless communications. Using the presented current-mode integrator, a dual mode channel selection filter is designed. To verify the current-mode integrator circuit, Hspice simulation using 1.8V Hynix $0.18{\mu}m$ standard CMOS technology was performed and achieved $50.0{\sim}4.3dB$ gain, $2.29{\sim}10.3MHz$ unity gain frequency. The described third-order dual mode analog channel selection filter is composed of the current-mode integrator, and used SFG(Signal Flow Graph) method. The simulated results show 0.51, 2.40MHz cutoff frequency which is suitable for the Bluetooth and WCDMA baseband block each.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1452-1453
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• 2008

본 논문에서는 RF MEMS 패키징 플랫폼을 활용한 안테나 구조를 제안하고, 이를 바탕으로 마이크로머시닝 공정을 이용한 슬롯 결합형 원형 패치 안테나를 제작하였다. 제안된 안테나는 RF MEMS 패키징 플랫폼 상에서 패키징 물질을 안테나의 유전 물질로 이용하기 위하여 슬롯 결합형 급전 구조를 사용하였다. 한편, BCB를 이용한 폴리머 접착 접합 공정의 RF MEMS 패키징 플랫폼을 기반으로, 하판 유리기판과 상판 수정 기판을 일체화한 형태로 마이크로 스트립라인 안테나를 제작하였다. 최종 제작된 안테나는 20.36-GHz에서 -21 dB의 반사 손실 값을 나타내며, 1.7-GHz, 즉 8.3 %의 주파수 대역을 가진다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2015.07a
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• pp.306-307
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• 2015

본 논문에서는 ATSC (Advanced Television Systems Committee) 3.0 시스템을 위한 LDM (Layered Division Multiplexing) 기술을 제안하고, 그 성능을 전산실험을 통해 분석한다. 제안된 LDM 시스템은 기존의 TDM (Time Division Multiplexing) / FDM (Frequency Division Multiplexing) 기술에 비해 약 3 에서 9 dB 의 성능 이득을 나타낸다.

• Proceedings of the KIEE Conference
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• 2002.11b
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• pp.271-273
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• 2002

This paper proposes a process that determines inter-area TTC(total transfer capability) by supplementing the existing process. The process is composed of three steps, which is composed of (a) estimation of input data, (b) selection of contingencies, and (c) determination of the transfer capability. In this study, one step is added to develop the methodology that enhances the TTC.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.173-175
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• 2005

The effects of PCB Board on the filter characteristics such as insertion loss and transmission characteristics were investigated for the measurement of 5GHz LC filter. Insertion loss measured with PCB Board of Teflon is 0.3 dB lower in comparion with FR-4. The filter characteristics measured in the passband were different from the calculated results. In comparison with the calculated value, the measured value shows that center frequency is 20MHz lower, passband is narrower and insertion loss is larger. The difference of Insertion loss between Teflon and FR-4 increases with increasing measurement frequency.

• Journal of Pharmaceutical Investigation
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• v.17 no.3
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• pp.127-133
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• 1987

Dissolution characteristics and urinary excreted amount of commercially available three brands of sulfisoxazole tablets were investigated in order to elucidate the in vitro-in vivo correlations and relative bioavailability in humans. All the tablets tested met the K.P. IV and the USP XXI specifications for tablet weight variation, content uniformity, disintegration and dissolution. The disintegration and dissolution rate constants of sulfisoxazole tablets in pH 2.0 HCl-KCl buffer were reduced more significantly (p<0.05) than those in diluted HCl $(1{\rightarrow}12.5)$ and pH 6.5 phosphate buffer. It seemed to be attributed to the pH dependent solubility of sulfisoxazole. We could see that the relative bioavailability of brand B to sulfisoxazole powder was about 90% and that its value was higher than those of other two brands from the urinary excretion data obtained from eight healthy male volunteers by means of Latin square cross over design. No useful correlation was observed between the in vitro and in vivo studies in this experiment.

• 한국초전도학회:학술대회논문집
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• v.11
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• pp.8-8
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• 2001

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2012.07a
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• pp.23-25
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• 2012

기존의 무손실 컬러 이미지 압축 연구에는 하나의 색상 채널을 압축한 뒤에 이를 이용하여 나머지 색상 채널의 값을 예측하여 압축을 수행하는 방법이 많다. 또한, 각각의 채널을 독립적으로 압축하는 경우, 무손실 색상 변환(reversible color transform을 먼저 수행하는 것이 유리하다는 연구 결과도 있다. 본 논문에서는 무손실 컬러 이미지 압축을 위한 새로운 색상변환 방법을 제안한다. 새롭게 제안하는 색상 변환은 R, G, B 색공간에서 표현된 이미지를 YCuCv 색공간으로 변환하는데, 기존의 방법에 비해 채널 간 상관관계를 효과적으로 제거한다. 실험 결과, 제안하는 방법은 기존의 무손실 색상 변환 방법에 비해 평균 2.6% 엔트로피를 감소시키는 성능 향상을 보인다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2006.11a
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• pp.153-156
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• 2006

본 논문에서는 T-DMB 수신기의 채널추정 성능향상을 위한 잡음감소 기법을 제안한다. 일반적으로 T-DMB 수신기에서의 채널추정은 파일럿 신호 추출과 채널계수 추정에 의해 수행된다. 채널추정의 성능은 수신 SNR (Signal to Noise Ratio)과 연관되어 추정된 채널계수에 남아있는 잡음성분에 의해 결정되기 때문에, 잔존하는 잡음성분을 감소시키는 것은 매우 중요하다. 이러한 잡음성분을 감소시키기 위해, M-point 가중이동평균(weighted moving average)을 기반으로 한 잡음제거 기법을 제안한다. 전산 실험에 의하면, 제안된 방법은 등화 후 SER (Symbol Error Rate) 측면에서 기존의 방법에 비해 2-3 dB의 성능 향상을 보인다.