• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.469-474
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• 2003

Recently, to overcome the disadvantages of RC decks, advanced countries such as Japan and USA, and Europe are using prestressing connection precast decks and loop connection precast decks. The prestressing connection precast deck, however, has a weakness against steel corrosion, because of unreliable enforced grouting. The relatively low loading and fatigue capacities of the loop connection precast deck make it difficult to be used for the bridge that requires high fatigue resistance due to the frequent over loaded vehicles. This research proposes the improved connecting method for the precast decks to minimize its shortcomings based on both numerical analyses and full scale model tests. The proposed method maximizes the advantages of precast decks and extends it's service life.

• Computers and Concrete
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• v.19 no.4
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• pp.405-411
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• 2017

Carbon Fiber Reinforced Plastic (CFRP) has commonly been used to strengthen existing RC structures. Wrapping the whole component with CFRP is an effective method and simple to execute. Besides, specific configuration of CFRP sheets (L, X and T shape) has also been considered in some experiments to examine CFRP effects in advance. This study aimed to provide an optimal CFRP configuration to effectively retrofit the beam-column connection using continuous material topology optimization procedure. In addition, Moved and Regularized Heaviside Functions and penalization factors were also considered. Furthermore, a multi-material procedure was also used to compare with the results from the single material procedure.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.43-43
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• 2000

In this paper, we introduce a case study of developing a miniature humanoid robot that has 16 degrees of freedom and is able to perform statically stable walking. The developed humanoid robot is 37cm tall and weighs 1,200g. RC servo motors are used as actuators. The robot can walk forward and turn to any direction on even surface. It equipped with a small digital camera, so it can transmit vision data to a remote host computer via wireless modem. The robot can be operated in two modes; One is a remote-controlled mode, in which the robot behaves according to the command given by a human operator through the user-interface program running on a remote host computer, the other is a stand-alone mode, in which the robot behaves autonomously according to the pre-programmed strategy. The user-interface program also contains a robot graphic simulator that is used to produce and verify the robot's gait motion. In our walking algorithm, the ankle joint is mainly used lot balancing the robot. The experimental results shows that the developed robot can perform statically stable walking on even surface.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.6B
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• pp.802-809
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• 2001

이동통신 채널에서 압축된 동영상 정보를 전송하게 되면 다경로 전송으로 인한 페이딩 영향과 시, 공간상으로 압축된 동영상 정보의 오류 전파 때문에 최종적으로 복원되는 동영상 신호의 화질이 크게 저하된다. 이에 능동적으로 대처하기 위하여 다양한 오류 정정 부호화 기법들이 전체 정보량 증가를 감수하면서 제안되어 왔다. 본 논문에서는 이동통신 환경에서 압축된 동영상 신호의 안정적인 전송을 위해서 ITU-T H.263 기법으로 압축된 동영상 정보에 두 종류의 다전송율 지원 오류 정정 부호들을 적용한 경우의 동영상 보호 능력을 분석 비교한다. 즉 표준기법에서 널리 사용되는 RCPC(rate compatible punctured convolutional) 부호와 RC 특성을 갖는 turbo 부호인 RCPT(rate compatible punctured turbo) 부호를 사용한 동영상 부호 시스템의 성능을 가산 백색 잡음 채널과 레일리 페이딩 채널에서 해석하고, 압축과 오류 정정 부호화율의 동시 최적화를 살펴본다.

• Magazine of the Korea Concrete Institute
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• v.10 no.5
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• pp.159-165
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• 1998

중트럭 통행으로 인한 철근콘크리트 교량바닥판의 열화는 교량구조물을 유지보수하는데 있어 심각한 문제 중 하나이며, 프리캐스트 바닥판을 이용한 교량바닥판의 시공 및 교체 방법이 실용적이며 효과적인 방법으로 인식되고 있다. 본 연구에서는 횡방향 ddusruf부에 종방향 프리스트레싱을 도입한 프리캐스트 바닥판의 모델을 제작하여 바닥판간 횡방향 연결부의 강성 평가 및 연결부의 피로 거동을 파악하기 위해서 피로실험을 수행하여 피로하중하에서의 휨강성의 변화, 균열발생 및 파괴하중 등을 측정하였다. 실험결과를 통해서 피로하중하에서 프리스트레스 프리캐스트 부재의 프리스트레스 효과를 평가하였으며, 현장타설에 의해서 시공되는 일반 RC 부재에 비해서 우수한 구조적 거동을 보여주는 적정량의 종방향 프리스트레스 크기를 결정하였다.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.507-510
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• 2005

Euro form which constructs the present RC structures is used widely by the form method of construction of a wall type structure had much consumption of the human power and equipments by the assembly and the demolition, and the complement was required according to demerit with much leakage of cement paste by the form joint, so it developed the new pillar type form system. On the study, in order to consider the modification characteristic by lateral pressure which does the influence most important for the new developed pillar type form system performance, research of a paper manufactured a miniature wall form model, and advanced performance evaluation focusing on lateral pressure. Moreover, lateral pressure evaluation of a new style system was actually gone on through the on-site experiment about a part of wall type srutcture spot for a model experiment and its result on the foundation which is the purpose in evaluating on-site application possibility propriety at the foundation time of wall type concrete structure construction of a pillar type form system.

• International Journal of High-Rise Buildings
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• v.8 no.3
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• pp.161-167
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• 2019

Making full use of material strength, maintaining sufficient ductility of structural components, and ensuring simple and robust connections are crucial to the development of steel-concrete composite structures. The steel-tubed concrete structure uses thin-walled steel tube to provide confinement, so that the strength and ductility of the concrete core are improved. Meanwhile, the thin-walled steel tube is terminated at the beam-column joint to avoid the local buckling problem and simplify the connections between steel tube and RC members. A brief overview of the development of steel-tubed concrete structures is presented. Through the discussion on the structural behavior of steel-tubed concrete and the introduction of typical practical projects, the prospects for future research are highlighted.

• Structural Engineering and Mechanics
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• v.85 no.3
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• pp.353-367
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• 2023

An extended parametric study based on nonlinear finite element analyses is performed to assess the key factors affecting the shear behaviour of exterior beam-column joints of unbraced reinforced concrete frames. Extensive results are presented, the major conclusion being that the few shear behaviour models for exterior reinforced concrete beam-column joints available in the literature do not properly account for some of the most influential factors. The present results are also compared with recently published results for interior joints, showing that while some factors have a similar influence on interior and exterior joints others are relevant for only one of these types of joints. This also confirms, numerically, that some resisting mechanisms of exterior joints differ from those of interior joints.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.06a
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• pp.161-162
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• 2020

Cracks are caused by drying shrinkage between the upper part of the underground parking lot and the apartment wall. As a result of the investigation, the distance between the apartment and the apartment is more than 45m, and the top slab of the underground parking lot is usually flat when there is not with steps. Therefore, the crack occurs more when the underground parking lot is a PC slab than a RC slab. In this study, the reduction of cracks was conducted by extending the slab, expanding the beam size, increasing the wall thickness, and installing a delay joint on slab. In each case, a finite element analysis was performed to examine the crack reduction method.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.2
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• pp.160-169
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• 2015

In this study, experimental research was carried out to improve the seismic performance of reinforced concrete exterior beam-column joint regions using replacing recycled coarse aggregate with hybrid fiber (steel fiber+PVA fiber) in existing reinforced concrete building. Therefore it was constructed and tested seven specimens retrofitting the beam-column joint regions using such retrofitting materials. Specimens, designed by retrofitting the beam-column joint regions of reinforced concrete building, were showed the stable failure mode and increase of load-carrying capacity due to the effect of crack control at the times of initial loading and bridge of retrofitting hybrid fiber during testing. Specimens BCJGPSR series, designed by the retrofitting of replacing recycled coarse aggregate with hybrid fiber in reinforecd beam-column joint regions were increased its maximum load carrying capacity by 1.01~1.04 times and its energy dissipation capacity by 1.06~1.29 times in comparison with standard specimen BCJS. Also, specimen $BCJGPSR_1$ were increased its energy dissipation capacity by 1.33~1.65 times in comparison with specimens BCJS, BCJP and BCJGPR series for a displacement ductility of 9.