• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2011년도 춘계 학술논문 발표대회 1부
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• pp.41-42
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• 2011

In this study, VA/E/MMA-modified mortars with nitrite-type hydrocalumite were prepared with various calumite contents and polymer binder-ratios, and tested for chloride ion penetration, carbonation and drying shrinkage. As a result, the chloride ion penetration and carbonation depths were somewhat increased with calumite contents, but those were remarkably decreased depending on the polymer-binder ratios. The 28-d drying shrinkage showed a tendency to increase with polymer-binder ratios and calumite contents. VA/E/MMA-Modified mortars with a calumite of 10 % were dissatisfied with KS requirements. Accordingly, a calumite content of 5 % for the VA/E/MMA-modified mortars with calumite is recommended.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집
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• pp.358-361
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• 2001

A new photoalignment material PM15CA, poly{N-(phenyl)maleimide-co-3-[4-(pentyloxy) cinnamate]propyl-2-hydroxy-1-methacrylate}, was synthesized and the electro-optical (EO) characteristics in the vertical-aligned (VA) liquid crystal display (LCD) photo-aligned on the photopolymer surface were studied. Excellent voltage-transmittance(V-T) characteristics in the VA-LCD photoaligned with polarized UV exposure of oblique direction on the pohotopolymer surfaces for 1 min can be achieved. The transmittance of the VA-LCD photoaligned on the photopolymer surface decreased with increasing UV exposure time. We suggest that the decrease of transmittance in the VA-LCD photoaligned on the photopolymer surface is attributed to the dissociation of the ester linkage in the photodimerized cinnamate structure with increasing UV exposure time

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.515-518
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• 2000

We studied the viewing angle characteristics of a negative dielectric anisotropy nematic liquid crystal (NLC) using the new vertical-alignment (VA)-1/6 cell on a rubbed polyimide (PI) surface. Good voltage-transmittance (V-T)characteristics using the new VA-1/6 cell without a negative compensation film were obtained. The iso-viewing angle characteristics using the new VA-1/6 cell without the negative compensation film can be achieved.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 추계학술대회 논문집 학회본부
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• pp.111-113
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• 1994

For the analysis of characteristics of a superconducting transformer, we designed and fabricated a 5kVA superconducting transformer with two kinds of secondary winding. Using the results of the open and short tests, we calculated the parameters of its equivalent circuit. We designed also a 5kVA conventional transformer with the same design conditions as the superconducting one. The performances of the superconducting transformer were compared with the performances of the designed conventional transformer and another 5kVA distribution transformer.

• Journal of the Optical Society of Korea
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• 제5권1호
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• pp.16-19
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• 2001

A photopolymer, copoly (M4Ch-ChMA), copoly ((4-methacryloyloxy) chalcone-cholesteryl methacrylate), was synthesized in this study. The electro-optical (EO) characteristics for the photo-aligned vertical-alignment (VA)-liquid crystal display (LCD) were investigated. Excellent voltage-transmittance curves for the VA-LCD photo-aligned by polarized UV exposure on the copoly (M4Ch-ChMA) surface were observed. The response time for the photo-aligned VA-LCD decrease with increasing UV exposure time. consequently, the photo-dimerized chalcone moiety increased with increasing UV exposure time, which then contributed to a low response time for the VA-LCD photo-aligned.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권2호
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• pp.390-407
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• 2011

Three-dimensional (3D) video technologies are becoming increasingly popular, as it can provide users with high quality and immersive experiences. However, color inconsistency between the camera views is an urgent problem to be solved in multi-view imaging. In this paper, a perception-based color correction method for multi-view images is proposed. In the proposed method, human visual sensitivity (VS) and visual attention (VA) models are incorporated into the correction process. Firstly, the VS property is used to reduce the computational complexity by removing these visual insensitive regions. Secondly, the VA property is used to improve the perceptual quality of local VA regions by performing VA-dependent color correction. Experimental results show that compared with other color correction methods, the proposed method can greatly promote the perceptual quality of local VA regions greatly and reduce the computational complexity, and obtain higher coding performance.

• Journal of Power Electronics
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• 제19권2호
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• pp.463-474
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• 2019

This paper presents the effect of winding configuration on the kVA rating of a wye-connected autotransformer applied to a 12-pulse rectifier. To describe the winding configuration of the wye-connected autotransformer, position and proportional parameters are defined and their quantitative relation is calculated. The voltages across and currents through the windings are measured under different winding connections. Consequently, a relation between the kVA rating and position parameter is established in accordance with the analysis, and the optimal winding configuration is obtained on the basis of this relation. A wye-connected autotransformer with the least equivalent kVA rating and simplest winding configuration is designed and applied to the 12-pulse rectifier. Simulations and experiments are conducted to validate the theoretical analysis.

• 방송공학회논문지
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• 제24권2호
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• pp.292-298
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• 2019

본 논문에서는 클라우드 서버와 영상 품질 향상 알고리즘을 이용하여 고화질의 영상을 서비스하는 방법을 소개한다. 즉, 논문에서 제안하는 ViVa (Video Value Addition)의 개념을 바탕으로 저화질 영상을 서비스하는데 필요한 전송 비트레이트와 계산량으로 고화질의 영상을 서비스함으로써 기존 스트리밍 서비스 대비 향상된 시스템을 제안한다.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2010년도 추계학술발표대회
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• pp.1190-1193
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• 2010

SOiVA는 양방향 동영상 서비스를 위한 TTA 정보통신 표준이다. SOiVA 서비스는 다양한 정보를 표현하기 위해 메타데이터를 이용하는데, 이 메타데이터에는 그 중요성 때문에 반드시 제 3자로부터 보호되어야 하는 내용이 포함되어 있다. 이 중 일부가 외부에 노출되거나 유실 조작될 경우 큰 문제를 야기할 수 있으므로 반드시 적합한 보안 시스템이 필요하다. 본 논문에서는 전자서명과 암호화 등의 기술을 이용해 SOiVA 메타데이터 보안 시스템을 설계하고, 타당성을 검증하기 위해 시스템을 구현하고 예제메타데이터에 대하여 시험하였다.

• ETRI Journal
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• 제36권2호
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• pp.253-263
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• 2014

In the near future, traditional narrow and fixed viewpoint video services will be replaced by high-quality panorama video services. This paper proposes a visual-attention-aware progressive region of interest (RoI) trick mode streaming service (VA-PRTS) that prioritizes video data to transmit according to the visual attention and transmits prioritized video data progressively. VA-PRTS enables the receiver to speed up the time to display without degrading the perceptual quality. For the proposed VA-PRTS, this paper defines a cutoff visual attention metric algorithm to determine the quality of the encoded video slice based on the capability of visual attention and the progressive streaming method based on the priority of RoI video data. Compared to conventional methods, VA-PRTS increases the bitrate saving by over 57% and decreases the interactive delay by over 66%, while maintaining a level of perceptual video quality. The experiment results show that the proposed VA-PRTS improves the quality of the viewer experience for interactive panoramic video streaming services. The development results show that the VA-PRTS has highly practical real-field feasibility.