• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2002년도 추계학술발표대회 논문집
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• pp.276-279
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• 2002

A problem formulation and solution for design optimization of laminated composite channel section beam is presented in this study. The objective of this study is the determination of optimum section dimensions of composite laminated channel section beam which has equivalent flexural rigidities to flexural rigidities of steel channel section beam. The analytical model is based on the laminate theory and accounts for the material coupling for arbitrary laminate stacking sequence configuration. The model is used to determine the optimal section dimensions of composite channel section beam. The web height, flange width and thickness of the beam are treated as design variables. The solutions described are found using a global search algorithm, Genetic Algorithms (GA).

• 한국인터넷방송통신학회논문지
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• 제22권4호
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• pp.59-65
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• 2022

본 논문에서는 디지털 능동위상배열 안테나를 간략히 소개하고 주 빔의 부엽을 차단하기 위해 적용된 이중 채널 부엽 차단 빔 형성 방법에 대해 기술하였다. 그리고 안테나 주 빔 및 부엽 차단 빔 설계 결과와 안테나 근접전계 측정 결과로부터 안테나 성능을 검증하였다. 다음으로 기존의 이중 채널 부엽 차단 빔 운용 방식 보다 채널수를 줄이기 위해 단일 채널 부엽 차단 빔 형성 방법을 제안하고, 제안한 방법으로 부엽 차단 안테나에 대한 소자별 가중치 분포를 설계하였다. 마지막으로 설계된 단일 채널 부엽 차단 빔 패턴과 차단 능력을 검증하고 이중 채널 부엽 차단 빔과 비교하였다. 또한, 디지털 능동위상배열 안테나의 수신 근접전계 시험을 통해 측정한 이중 채널 부엽 차단 빔과 제안된 단일 채널 부엽 차단 빔 패턴 및 부엽 차단 성능을 비교/검증함으로써 제안된 부엽 차단 빔 형성 방법에 대한 유효성을 확인하였다.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2003년도 춘계학술발표대회 논문집
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• pp.69-73
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• 2003

A open section thick composite beam model is suggested in this study. In the model, the primary and secondary warping and transverse shear effects are incorporated. The rigidities associated with thick channel composite beam and thin channel composite beam are obtained and compared. The results show that the difference among rigidities of the thick and thin composite beams increase as the wall thickness increases.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2008년도 정기 학술대회
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• pp.490-494
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• 2008

U-Channel Bridge is effective bridge type, because its edge beam performs role of barrier and enables to reduce additional dead loads. Although it is effective to reduce additional dead loads, there is possibility of bridge collapse under impact load due to car crash. Also, edge beam must have ability to induce safe driving and prevent falling accidents. Therefore, it requires behavior analysis and property investigation through the vehicle impact crashing edge beam. This study presents method of structural analysis of U-channel bridge and investigates design specifications for the effect of the edge beam under the vehicle impact. Also, it carries out stability investigation of behavior of edge beam and slab, based on Korean Highway Bridge Design Specifications and AASHTO LRFD Bridge Design Specification.

• 한국안전학회지
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• 제24권3호
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• pp.39-46
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• 2009

A recent and promising method for shear strengthening of reinforced concrete(RC) members is the use of near surface mounted(NSM) fiber reinforced polymer(FRP) reinforcement. In the NSM method, the reinforcement is embedded in grooves cut onto the surface of the member to be strengthened and filled with an appropriate binding agent such as epoxy paste or cement grout. This paper illustrates a research program on shear strengthening of RC beams with NSM channel-type FRP beams which is developed in this study. The objective of this study is to clarify the role of channel-type FRP beam embedded to the beam web for shear strengthening of reinforced concrete beams. Included in the study are effectiveness in terms of spacing and angle of channel-type FRP beams, strengthening method, and shear span ratio. the study also aims to understand the additional shear capacity due to glass fiber reinforced polymer beams and carbon reinforced polymer beams. And anther objective is to study the failure modes, shear strengthening effect on ultimate force and load deflection behavior of RC beams embedded with channel-type FRP beams on the shear region of the beams.

• 한국통신학회논문지
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• 제40권3호
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• pp.459-468
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• 2015

본 논문에서는 하나의 AP가 다수의 사용자를 지원하는 상향링크 다중사용자 하이브리드 빔포밍 시스템을 고려한다. 상향링크 다중사용자 하이브리드 빔포밍 시스템의 성능은 채널에 아날로그 빔이 결합된 형태의 유효 채널에 의해서 결정된다. 따라서 시스템의 성능을 최대화하기 위해서는 채널의 정보를 획득하고 획득된 채널 정보를 이용해서 아날로그 빔을 적절히 선택해야 한다. 본 논문에서는 상향링크 다중사용자 하이브리드 빔포밍 시스템에 적합한 채널 추정 방법과 저복잡도 아날로그 빔 선택 알고리즘을 제안한다. 또한 수학적으로 계산 복잡도 분석을 통해서 제안하는 저복잡도 아날로그 빔 선택 알고리즘이 최적의 아날로그 빔 선택 알고리즘에 비해서 복잡도가 훨씬 작은 것을 보여준다. 모의 실험 결과를 통하여 동일한 조건 하에서 제안된 저복잡도 아날로그 빔 선택 알고리즘이 최적의 아날로그 빔 선택 알고리즘에 비해 줄어든 계산 복잡도에 비하여 성능 면에서 열화가 거의 없는 것을 확인한다.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2008년도 정기총회 및 학술발표대회
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• pp.333-336
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• 2008

U-Channel Bridge is effective bridge type, because its edge beam performs role of barrier and enables to reduce additional dead loads. Nevertheless, there is possibility of bridge collapse under impact load due to car crash. Also, edge beam must have ability to induce safe driving and prevent falling accidents. Therefore, this study carries out analysis of behavior of edge beam and slab and evaluation of structural stability under impact loads, based on Korean Highway Bridge Design Specifications and AASHTO LRFD Bridge Design Specification. According to analysis result, the maximum stress of edge beam and slab satisfies specification of allowable stress.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 I
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• pp.35-38
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• 2003

We propose a switched beamforming to improve the reception performance of VSB system in severe Rayleigh fading channel. The VSB system has only about 3% of known training signal for the receiver in a data field and the reception performance of VSB receiver is degraded significantly when there are near-0 dB ghosts in receiving signal. The switched beamforming forms several beams in different directions and selects only one beam among them. For the selection of a beam with best channel condition for VSB equalizer, we extracted the channel profiles in time domain for all the beams by correlating the PN511 sequence in VSB field sync and selected optimal beam by comparing the channel profiles. The simulation results show that the proposed method improves the reception performance of VSB system in severe Rayleigh channel.

• Journal of Electrical Engineering and Technology
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• 제4권3호
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• pp.405-409
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• 2009

A polarization-independent multiwavelength-switchable fiber filter is proposed based on a polarization beam splitter and fiber coupler, which can function as a polarization-independent transmission or reflection-type interleaving filter. The proposed filter consists of a polarization beam splitter and a Sagnac birefringence loop composed of a 50:50 coupler, high birefringent fibers, and two quarter-wave plates. In the proposed filter, a transmission-type interleaver with a channel isolation > 18 dB or a reflection-type one with a channel isolation of ${\sim}3$ dB, whose channel spacing and switching displacement were 0.8 and 0.4 nm in common, respectively, could be obtained. A channel interleaving operation could be performed by the proper control of waveplates within the Sagnac birefringence loop.

• 한국통신학회:학술대회논문집
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• 한국통신학회 1987년도 춘계학술발표회 논문집
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• pp.176-179
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• 1987