• Proceedings of the IEEK Conference
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• 2000.06a
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• pp.77-80
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• 2000

In this paper, we implemented the voice modem using the multicarrier DS-CDMA in powerline channels. Both TMS320C5402 of Texas Instrument and FPGA FLEX 10K EPF10K100ARC240 of ALTERA are used to realize the proposed system. For robustness in the powerline channel, we used multicarrier DS-CDMA modulation, convolutional encoding/Viterbi decoding, and interleaving. Finally, we showed satisfactory performance in the laboratory experiment.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.10
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• pp.1820-1822
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• 2007

In this paper we fabricated a fiber device composed of cascaded long-period fiber gratings between which a birefringent erbium-doped fiber was inserted and proposed its application as a polarization-controlled interleaved signal gating fiber device. Because the core and cladding modes of the fabricated fiber device have polarization-dependent phase difference due to the birefringence of the erbium-doped fiber, its interference spectrum can be modulated by varying the input polarization.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10a
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• pp.269-271
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• 2000

이동 컴퓨팅 환경은 분산 컴퓨팅 환경과는 달리 네트웍의 낮은 신뢰성과 제한된 대역폭을 가지고, 이동 호스트 또한 제한된 저장장치와 배터리만을 사용할 수 있으며 트랜잭션(transaction)은 장시간에 결쳐 수행되는 특성을 가진다. 이동 컴퓨팅 환경에서는 전통적인 트랜잭션의 동시성 제어 기법 대신, 트랜잭션의 시맨틱스(semantics)를 이용하여 동시성을 향상시킬 수 있다. 본 연구에서는 중첩된 트랜잭션의 구조를 단순화시킨 단계분할(step- decomposition) 기법을 사용하여, 서브트랜잭션(sub-transaction)의 시맨틱 타입(semantic type) 별로 인터리빙(interleaving)을 제어함으로써 트랜잭션의 동시성을 향상시키는 기법을 제안하고자 한다.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04a
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• pp.967-969
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• 2004

본 논문에서는 표준 셀 배치기 Mongrel을 소개하고 두 가지 분할 기법(FM, hMETIS)을 통해 효율적인 초기 배치를 얻음으로써 Mongrel의 성능을 개선한다. Mongrel은 middle-down 방법론을 채택한 전역 배치와 상세 배치의 2단계 표준 셀 배치기이며 전역 배치 단계에서는 RBLS(Relaxation-Based Local Search)를, 그리고 상세 배치 단계에서는 최적 인터리빙(optimal interleaving) 기법을 통해 최적화 알고리즘을 수행한다. MCNC 벤치마크 회로를 이용한 실험을 통해 Mongrel의 성능을 평가하고 효율적인 초기배치가 최종 결과에 미치는 영향을 분석한다.

• Proceedings of the IEEK Conference
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• 2000.07a
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• pp.132-135
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• 2000

In this paper, we propose to exploit a multi-code CDMA scheme for power line communication (PLC) systems, and its performance on non-Gaussian impulse and harmonic noises is presented. The proposed multi-code CDMA scheme utilizes convolutional coding and block interleaving to combat with the non-Gaussian noises, and simulation results indicate effective alleviation of these noises, and thus significant bit error rate improvement by the proposed scheme even under strict restriction of frequency band allowed in PLC systems.

• Proceedings of the KIEE Conference
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• 2005.10a
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• pp.79-81
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• 2005

본 논문은 펄스 삽입 보조 회로를 갖고 있는 12-펄스 브리지 4대를 사용한 36-펄스 back-to-back 전압원 컨버터를 제안한다. 제안된 back-to-back 접압원 컨버터는 교류 연계점에서 유효전력과 무효전력의 독립적인 제어가 가능하다. 펄스 수를 증가하는 원리는 이론적 접근을 사용하여 분석되었다. 제안된 시스템의 동작 타당성은 PSCAD/EMTDC 소프트웨어의 시뮬레이션을 통해 검증되었다. 제안된 back-to-back 전압원 컨버터는 HVDC와 FACTS 장치로 널리 사용될 수 있다.

• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.447-448
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• 2020

3-Level Boost Converter(TLB)의 병렬 연결 시, 배터리 및 커패시터의 맥동 전류 저감을 위하여 인터리빙 동작이 요구된다. 그러나 기존의 TLB 병렬모듈은 인터리빙 운전이 불가능하다. 본 논문에서는 TLB 병렬모듈의 인터리빙 운전이 가능한 회로의 동작을 기술하고, 커패시터 중성점 연결 시 맥동 전류저감 효과를 분석한다.

• Journal of Adhesion and Interface
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• v.10 no.2
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• pp.106-112
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• 2009

In the present work, novel biocomposites made with biodegradable Lyocell woven fabrics and poly (butylene succinate) were successfully fabricated for the first time. Lyocell/poly(butylene succinate) biocomposites with different fiber loadings of 0, 30, 40, 50 and 60 wt% were prepared by compression molding with a sheet interleaving manner. The effect of Lyocell fabric loading on the interlaminar shear strength, tensile and flexural properties, heat deflection temperature, thermal expansion behavior, and thermal stability of the biocomposites was investigated. The properties strongly depended on the fabric loading and the results were consistent with each other. It was demonstrated that the Lyocell fabrics played a remarkable role in improving the properties of poly(butylene succinate) resin by incorporating the fabrics into the resin. The greatest inter-laminar, tensile, flexural and thermal properties of the biocomposites were obtained with Lyocell fabrics of 50% by weight.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.1
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• pp.139-146
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• 2017

The ISDB-T(Integrated Service Digital Broadcasting Terrestrial) can be used in the multipath and impulsive noise, also it provide good performance over mobile reception environment since it use the OFDM(Orthogonal Frequency Division Multiplexing) based transmission technology and time interleaving technology. One segment and full segment are divided according to the number of the assigned segment. And one-segment broadcasting receiver can design and implement without high levels of technology than the full-segment broadcasting receiver using 64QAM(64 Quadrature Amplitude Modulation) since it uses QPSK(Quadrature Phase Shift Keying) modulation/demodulation. However, it has a constraint in the display size and resolution due to data-rate limits. In this paper, we design and implementation of full-segment ISDB-T receiver module which support HD resolution for set-top box, digital TV, navigation. In experimental results, the implemented full-segment ISDB-T receiver module was satisfactory for all of the desired functions.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.37 no.3
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• pp.93-103
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• 2000

This paper describes Internet multicast routing protocols over MPLS (Multiprotocol Label Switching) networks. Internet multicast routing protocols are divided into 3 categories in terms of tree types and tree characteristics: a shortest path tree, a shared tree and hybrid tree types. MPLS should support various multicast mechanisms because of extremely different IP multicast architectures, such as uni-/bi-directional link, Flooding/prune tree maintenance mechanism, the existence of different tree types with the same group, etc. There are so many problems over MPLS multicast that the solutions can't be easily figured out. In this paper, we make a few assumptions on which the solutions of IP multicast routing protocols over MPLS networks are given. A broadcasting label is defined for the shortest path tree types. Cell interleaving problems of the shared tree types is solved by using block-based transmission mechanism. Finally, the existing hybrid-type multicast routing protocol is reasonably modified to support MPLS multicast.