• Composites Research
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• 제30권1호
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• pp.7-14
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• 2017

In this paper, the inter-lamina shear strength (ILSS) of multi-wall carbon nanotube (MWNT) reinforced carbon fiber reinforced plastics (CFRP) and thin-ply composites were verified under low earth orbit (LEO) space environment. CFRP, MWNT reinforced CFRP, thin-ply CFRP and MWNT reinforced thin-ply CFRP were tested after aging by using accelerated ground simulation equipment. The used ground simulation equipment can simulate high vacuum ($2.5{\times}10^{-6}torr$), atomic oxygen (AO, $9.15{\times}10^{14}atoms/cm^2{\cdot}s$), ultraviolet light (UV, 200 nm wave length) and thermal cycling ($-70{\sim}100^{\circ}C$) simultaneously. The duration of aging experiment was twenty hours, which is an equivalent duration to that of STS-4 space shuttle condition. After the aging experiment, ILSS were measured at room temperature ($27^{\circ}C$), high temperature ($100^{\circ}C$) and low temperature ($-100^{\circ}C$) to verify the effect of operation temperature. The MWNT and thin-ply shows good improvement of ILSS at ground condition especially with the thin-ply. And after LEO exposure large degradation of ILSS was observed at MWNT added composite due to the thermal cycle. And the degradation rate was much higher under the high temperature condition. But, at the low temperature condition, the ILSS was largely recovered due to the matrix toughening effect.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2007년도 제28회 춘계학술대회논문집
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• pp.110-113
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• 2007

하이드라진 추력기에 적용되는 분해촉매의 국산화 개발과정에 필수적으로 요구되는 사항이 추력기를 통한 성능평가 과정이며 특히, 추력기의 임무수명 요구조건을 평가하는 장기성능 연소시험을 통해 촉매에 대한 최종적인 성능검증이 이루어지게 된다. 본 논문에서는 이에 대한 사항으로 촉매에 대한 성능평가 및 장기성능시험에 대한 시험과정, 시험 시퀀스 및 결과분석에 대해 기술하였다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2012년도 춘계학술발표대회
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• pp.59.1-59.1
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• 2012

Organic thin-film transistors (OTFTs) with printable semiconductors are promising candidate devices for flexible active-matrix (AM) display applications. Yet, stable operation of actual display panels driven by OTFTs has seldom been reported up to date. Here, we demonstrate a flexible reflective type polymer dispersed liquid crystal (PDLC) display, in which inkjet-printed OTFT arrays are used as driving elements with excellent areal uniformity in terms of device performance. As the active semiconductor, a novel, ambient processable conjugated copolymer was synthesized. The stability of the devices with respect to electrical bias stress was improved by applying a channel-passivation layer, which suppresses the environmental effects and hence reduces the density of trap states at the channel/dielectric interface. The combination of high performance and high stability OTFT devices enabled the successful realization of stable operating flexible color-displays by inkjet-printing.

• 한국결정성장학회지
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• 제3권1호
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• pp.45-58
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• 1993

대용량 석탄 화력 발전소의 계속적인 가동 개시와 함께 석탄회 발생량은 연간 약 200만톤에 달하고 있다. 매립비의 상승, 환경 문제와 석탄회 발생량의 증가 때문에 석탄회 재사용에 대한 요구가 높아지고 있다. 본 논문은 석탄회와 점토를 혼합하여 제작된 벽돌소지에 대하여, 곡강도와 미세구조와의 관계를 검토하였다. 기공의 크기와 양, 기공과 기공을 연결하는 기지의 소결정도, 조립 석영입자에 의한 균열이 곡강도와 밀접한 관계가 있음을 밝혀냈으며, 석탄회가 15wt.% 첨가된 시편이 전 소성온도 범위에서 우수한 곡강도를 보였다.

• 대한전기학회논문지:전력기술부문A
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• 제51권8호
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• pp.409-416
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• 2002

This paper presents a fault location algorithm using direct 3-phase circuit analysis for distribution power networks. The unbalanced feature of distribution networks due to single phase loads or asymmetric operation prohibits us from using the conventional symmetrical component transformation. Even though the symmetrical component transformation provides us with a very easy tool in three phase network analysis, it is limited to balanced systems in utilizing its strong point, which is not suitable for distribution networks. In this paper, a fault location algorithm using direct 3-phase circuit analysis is developed. The algorithm is derived and it Is shown that the proposed method if we use matrix inverse lemma, is not more difficult then the conventional methods using symmetrical component transformation. Since the symmetrical component transformation is not used in the suggested method, unbalanced networks also can be handled with the same difficulty as balanced networks. The case study results show the correctness and effectiveness of the proposed algorithm.

• 펄프종이기술
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• 제35권4호
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• pp.48-56
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• 2003

In this work an integrated model for paper plants combining wet-end and dry section is developed and a model predictive control scheme based on the plant model is proposed. Closed-loop process identification method is employed to produce a state-space model. Thick stock, filler flow, machine speed and steam pressure are selected as input variables and basis weight, ash content and moisture content are considered as output variables. The desired output trajectory is constructed in the form of 1st-order dynamics. Results of simulations for control of grade change operations are compared with plant operation data collected during the grade change operations under the same conditions as in simulations. From the comparison, we can see that the proposed model predictive control scheme reduces the grade change time and achieves stable steady-state.

• 한국전자거래학회지
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• 제23권1호
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• pp.37-45
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• 2018

현재 프로그램이 운용되는 시스템은 기존의 싱글코어 및 멀티코어 환경을 넘어서 매니코어, 부가 프로세스 및 이기종 환경까지 그 영역이 확장되고 있는 중이다. 하지만, 기존 연구의 경우 NVIDIA 벤더에서 나온 아키텍쳐 및 CUDA로의 병렬화가 주로 이루어졌고 AMD에서 나온 범용 GPU 아키텍쳐인 GCN 아키텍쳐에 대한 성능향상에 관한 연구는 제한적으로 이루어졌다. 이런 점을 고려해 본 논문에서는 GCN 아키텍쳐의 GPGPU 환경인 OpenCL 내에서의 성능향상 기법에 대해 연구하고 실질적인 성능향상을 보였다. 구체적으로, 행렬 곱셈과 컨볼루션을 적용한 GPGPU 프로그램을 본 논문에서 제시한 성능향상 기법을 통해 최대 30% 이상의 실행시간을 감소시켰으며, 커널 이용률 또한 40% 이상 높였다.

• 한국실내디자인학회논문집
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• 제13권5호
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• pp.143-153
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• 2004

This research aimed to assess nursing homes for the elderly with geriatric diseases in Japan, and to prepare the knowledge basis to develop nursing home for the elderly with geriatric diseases in Korea. For this, researcher visited 5 facilities in Tokyo from October 3 to October 9 in 2002, collected data by observations, interviews, and visual materials by taking photographs. Visual materials were analyzed according to the environmental assessment matrix consisted of supportiveness, flexibility, efficiency in perception, accessibility, safety, amenity, and social Interaction that were assorted and were given a name by these researchers in the process of this research. Among the characteristics of environmental design of the analysis cases, 992 items picked out from 722 visual materials were used in the analysis. The data were analyzed using the frequency and percentage with SPSS 11 program. The analysis results were the fellowing. The characteristics of recent nursing home design in Japan tended to focus on supportiveness, amenity, and efficiency in perception but to leave much desired in flexibility and safety. In each space, space to support outdoor activities tended to focus on efficiency in perception, space to support living activities tended to focus on amenities, space to support treatment and living tended to focus on supportiveness, space to support administration and operation tended to focus on supportiveness, and space to support movement tended to focus on amenities.

• 한국재료학회지
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• 제28권7호
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• pp.428-434
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• 2018

Hydrogen evolution on a steel surface and subsequent hydrogen diffusion into the steel matrix are evaluated using an electrochemical permeation test with no applied cathodic current on the hydrogen charging side. In particular, cyclic operation in the permeation test is also conducted to clarify the corrosion-induced hydrogen evolution behavior. In contrast to the conventional perception that the cathodic reduction reaction on the steel in neutral aqueous environments is an oxygen reduction reaction, this study demonstrates that atomic hydrogen may be generated on the steel surface by the corrosion reaction, even in a neutral environment. Although a much lower permeation current density and significant slower diffusion kinetics of hydrogen are observed compared to the results measured in acidic environments, they contribute to the increase in the embrittlement index. This study suggests that the research on hydrogen embrittlement in ultra-strong steels should be approached from the viewpoint of corrosion reactions on the steel surface and subsequent hydrogen evolution/diffusion behavior.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2013년도 추계학술대회
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• pp.77-80
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• 2013

SURF 알고리즘은 영상의 특징점 검출 및 서술자를 생성하는 알고리즘으로 크기와 회전, 조명 및 시점 등의 환경 변화에 강인한 특징을 가지고 있다. 이러한 특징 때문에 객체 인식, 파노라마 이미지, 3차원 영상 복원 등 영상처리 분야에서 많이 사용되고 있다. 하지만 SURF 알고리즘과 같은 대부분의 인식 알고리즘은 많은 양의 연산을 필요로 하기 때문에 실시간 구현이 어렵다. 본 논문은 SURF의 메모리 접근 횟수와 메모리 사용량을 분석하여 효율적인 메모리를 설계함으로써 메모리 접근 횟수와 메모리 사용량을 최소화하여 실시간 구현이 가능하도록 설계하였다.