• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.10a
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• pp.56-60
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• 2004

2단 또는 3단형으로 설계되고 있는 KSLV-I 발사체의 단연결부는 직경의 변화에 따라 원뿔대(Truncated cone) 구조물이 필요하다. 원뿔대형 구조물이 발사체의 외피일 경우에는 일반적인 실린더형 동체와는 다르게 공력에 의한 버페팅(buffeting)과 공력가열 등이 추가적인 설계인자로 고려되어야 한다. 복합재료 샌드위치 구조물은 외피의 굽힘 강성이 크고, 일체성형으로 실린더형 혹은 원뿔대형 구좁물을 쉽게 제작할 수 있어 단연결부에 적용되고 있다. 또한 위성어댑터(Payload Adapter)등에도 사용되어 우주발사체에는 매우 일반적인 구조물이다. 복합재료 샌드위치 구조물의 제작과 정적시험을 통하여 구조 특성을 알아보았다. 일체형 샌드위치 구조물의 효율을 높이기 위해서는 프레임과의 체결부를 효율적으로 설계하여야 하며 하중의 종류에 따라서 면재의 적층각도가 중요함을 알 수 있었다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.14 no.2
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• pp.193-202
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• 2001

현재 국내에서는 아파트 건물을 짓는데 벽과 바닥판으로만 이루어진 벽식 구조형식을 많이 사용하고 있다. 이러한 고층 아파트건물을 해석하기 위해서 ETABS나 MIDAS/BDS 같은 상용프로그램이 주로 사용되고 있다. ETABS는 해석상의 편의를 위하여 바다판을 강막으로 가정하여 모형화 하고 바닥판의 휨강성은 고려하지 않고 있다. 이러한 가정은 프레임 구조물을 해석할 때에는 합리적이라고 할 수 있다. 그러나 벽식 구조물은 바닥판의 휨강성이 전체 구조물의 횡방향 강성에 큰 영향을 미치므로 바닥판의 휨강성을 고려하지 않으면 전체 구조물의 강성을 과소평가하게 된다. 따라서 바닥판을 판요소로 세분하여 모형화 하는 것이 필요하다. 그러나 이때 많은 양의 해석 시간과 컴퓨터 메모리가 필요하게 된다. 따라서 본 연구에서는 부분구조법과 행렬응축기법을 사용하여 해석 시간과 컴퓨터 메모리의 사용을 줄이면서도 바닥판의 휨강성을 효율적으로 해석할 수 있는 해석 기법을 제안하였고 예제를 통하여 검증하였다.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.5 no.4
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• pp.74-81
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• 1996

This paper is to estimate sizing design sensitivity of linear and nonlinear vehicle frame structure using structural ananlysis result from ANSYS. Using design sensitivity results, optimal design of plane vehicle frame structure with buckling constraint is carried out the gradient projection method. Optimal design results are compares gradient projection method resrult with SUMT result.

• Journal of Broadcast Engineering
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• v.18 no.2
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• pp.297-310
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• 2013

In this paper, we present a model-based video bit rate estimation scheme for reducing the bit rate while maintaining a subjective quality in many video streaming services limited by network bandwidth, such as IPTV services. First, we extract major parameters which serve as an indirect measurement of frame's bits. Using those parameters, the proposed bit rate estimation scheme can extract candidate frames. Finally, the bit rate of each segment is estimated by statistical analysis and a mathematical model based on a given target quality. In experimental results, we show that the proposed scheme can reduce the bit rate on average by 43% in low-complexity video while maintaining the subjective quality. To find the appropriate bit rate based on video contents, the proposed schemes can estimate the bit rate with neither the repeated full encoding nor subjective quality test. On average, the bit rate can be automatically estimated by encoding the candidate frames of 4%.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.2
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• pp.58-65
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• 2021

As increasing social needs of pavement maintenance, pattern frame method has been constructed in Korea. The pattern frame not only increases the skid resistance of pavements but also improve the scenery. However, construction of the pattern frame currently relies on imported materials. In this paper, we localize the materials used in pattern frame and conduct performance verification on them. The important performance indicators are the adhesion strength of undercoating materials and the skid resistance of finished pattern frames. The adhesion strength was targeted at 1.4MPa, and the localization alternative material met the target performance with 2.35MPa, the skid resistance performance was targeted at 40BPN, and the localization alternative material met the target performance with 75BPN. In the case of localized materials, approximately 40% cost reduction (per 1m²)compared to imported materials was confirmed.

• Electronics and Telecommunications Trends
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• v.18 no.5 s.83
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• pp.27-36
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• 2003

본 논문은 SDR Forum에서 SDR용 모바일 플랫폼 구성을 위한 소프트웨어의 표준으로 인정된 차세대 개방형 소프트웨어 프레임워크인 SCA의 구조에 대해 기술한다. SCA 소프트웨어 프레임워크는 궁극적으로 단일 모바일 플랫폼 환경에서 하드웨어의 변경 없이 무선으로 다운로드한 소프트웨어의 동작으로 다양한 무선 접속환경을 구성할 수 있도록 하는 내장형 시스템 소프트웨어들의 표준을 추구한다. SCA는 분산 객체 모델의 표준인 CORBA Middleware와 더불어 다중 무선접속 응용프로그램을 구성하기 위하여 컴포넌트 구성물의 수행을 뒷받침하는 개방형 소프트웨어 구조로서 크게 RTOS, CORBA Middleware, CF, Portable Software Resource로 이루어진다. 본 고에서는 SCA 소프트웨어 프레임워크의 기본 구조와 기능들을 최신 표준 동향을 기반으로 분석하고, 개발 사례에 대해서도 간단히 소개한다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.3
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• pp.145-152
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• 2013

This study is to evaluate the thermal insulation of the curtain wall of the buildings constructed since the 1990s to the buildings currently under construction in 2011 and to provide the basic data for repairing and reinforcing and designing the thermal insulation. To this effect, the temperature difference by part was analyzed through measuring the inside and outside surface temperature of the curtain wall of the office building, and thereafter, the conditions of the thermal insulation and the thermal bridge part were examined. The result of the study is as follows; Not only in the winter season when the temperature difference between the indoor-outdoor is over $20^{\circ}C$, but also in the summer season when there is a small temperature difference, the temperature difference between the inside and outside of the frame is $2^{\circ}C{\sim}4^{\circ}C$ equally. Under such conditions as stated above, the thermal bridge occurred, which resulted from the heat flow of the steel frame part (mullion, transom), and therefore, the reinforcement of the thermal insulation is considered to be needed.

• Journal of Korean Association for Spatial Structures
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• v.13 no.4
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• pp.17-21
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• 2013

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.4
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• pp.531-538
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• 2006

Grating is an installed structure on the road for drain. This paper proposes a new product which can prevent the accumulation of earth and sand through the improvement of Grating structure. There were usually harmful insects and bad smell because of accumulated garbage in the frame of previous product. The product had a reverse-flowing sewage due to the bad draining in case of rain. The whole thing of the existing Grating installed with the one set of frame and main body should be changed when it was damaged. This study is to develop a structure which can separate grating main body from frame and grating main body can equip and separate after fixing frame to the manhole with cement. also install jig for the loss prevention and change for the better.

• Journal of the Korea Society for Simulation
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• v.28 no.2
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• pp.149-158
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• 2019

This paper introduces an integrated Modeling & Simulation framework for the efficient development of the rescue robot which rescues a wounded patients or soldiers and disposes a dangerous objects or explosive materials in the battlefields and disastrous environments. An integrated M&S(Modeling & Simulation) framework would have enabled us to perform the dynamic simulation program GAZEBO based Software-in-the-Loop Simulation(SILS) which is to replacing the robot platform hardware with a simulation software. An integrated M&S framework would help us to perform designing robot and performance validation of robot control results more efficiently. Furthermore, Tele-operation performance in the unstructured environments could be improved. We review a case study of applying an integrated M&S framework tool in validating performance of mobility stabilization control, one of the most important control strategy in the rescue robot.