• 한국응용과학기술학회지
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• 제24권1호
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• pp.1-9
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• 2007

It prepared the $TiO_2$ powder which has photo-catalytic activity in the visible-light by the wet process with titanium oxysulfate. The titanium $dioxide(TiO_2)$ by the wet process creates a new absorption band in the visible light region, and is expected to create photocatalytic activity in this region. Anatase $TiO_2$ powder which has photocatalytic activity in the visible light region, is treated using microwave and radio-frequency(RF) plasma. But, the $TiO_2$ powder for the visible light region, which also can be easily produced by wet process. The wet process $TiO_2$ absorbed visible light between 400nm and 600nm, and showed a high activity in this region, as measured by the oxidation removal of aceton from the gas phase. The AH-380 sample appears the yellow color to be strong, the catalytic activity in the visible ray was excellent in comparison with the plasma-treated $TiO_2$. The AH-380 $TiO_2$ powder, which can be easily produced on a large scale, is expected to have higher efficiency in utilizing solar energy than the plasma-treated $TiO_2$ powder.

• 한국정밀공학회지
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• 제21권6호
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• pp.94-101
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• 2004

From the Beckmann's reflection model of wave incident, reflected light from a surface is known to have not only specular but also diffuse components. The specular component dominant a surface for a mirror-like surface is distributed on the almost the same area as the spot on the surface, but the diffuse component region dominant f3r a rough surface spreads scattered on the larger areas than the spot. Therefore, statistic parameters from the scattered light distribution are more meaningful in the diffuse region, while the magnitude of rather meaning in the specular region. In usual, there need two sensors to acquire two kinds of information: Photo-detector for light intensity magnitude and image sensor for light intensity distribution. But dual sensor scheme requires a beam splitter usually to feed light to each sensor, and moreover there is not a combination rule to relieve the different sensor characteristics. In this study a new method is proposed for acquisition of the dual information using only an image sensor. Specular region is established on an image area being distinguished from a diffuse component, and laser power is adjusted so that no pixel of the image sensor in the specular region is saturated. Simulation based on the light reflection theory and the experimental results are quite well matched, and thus the proposed method was proved to be very useful for mirror-like surface measurement.

• 한국재료학회지
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• 제14권9호
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• pp.634-641
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• 2004

The photocatalytic performance of $TiO_2$ thin films coated on porous alumina balls using various aqueous $TiOCl_2$ solutions as starting precursors, to which 1.0 $mol\%$ transition metal ($Ni^{2+},\;Cr^{3+},\;Fe^{3+},\;Nb^{3+},\;and\;V^{5+}$) chlorides had been already added, has been investigated, together with characterizations for $TiO_2$ sols synthesized simultaneously in the same autoclave through hydrothermal method. The synthesized $TiO_2$ sols were all formed with an anatase phase, and their particle size was between several nm and 30 nm showing ${\zeta}-potential$ of $-25{\sim}-35$ mV, being maintained stable for over 6 months. However, the $TiO_2$ sol added with Cr had a much lower value of -potential and larger particle sizes. The coated $TiO_2$ thin films had almost the same shape and size as those of the sol. The pure $TiO_2$ sol showed the highest optical absorption in the ultraviolet light region, and other $TiO_2$ sols containing $Cr^{3+},\;Fe^{3+}\;and\;Ni^{2+}$ showed higher optical absorption than pure sol in the visible light region. According to the experiments for removal of a gas-phase benzene, the pure $TiO_2$ film showed the highest photo dissociation rate in the ultraviolet light region, but in artificial sunlight the photo dissociation rate of $TiO_2$ coated films containing $Cr^{3+},\;Fe^{3+}\;and\;Ni^{2+}$ was measured higher together with the increase of optical absorption by doping.

• 정보처리학회논문지B
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• 제13B권4호
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• pp.383-392
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• 2006

본 논문에서는 영역기반 영상검색의 성능 향상을 위한 피드백 알고리즘으로 다중 클래스를 갖는 확률적 신경망(Probabilistic Neural Networks)을 이용한 방법론을 제안하고 이를 영역기반 영상 검색 시스템인 FRIP(Finding Regions In the Pictures) 시스템에 적용하였다. 본 논문에서 제안하는 피드백 알고리즘은 특정 벡터가 독립적이라는 가정을 할 필요가 없으며 보다 상세한 분류를 위해 추가적인 클래스들을 추가할 수 있도록 허용하고 있다. 또한 단지 4개 층(layer)만을 가지고 있음으로 학습을 위한 계산시간이 적게 든다는 장점이 있다. 추가적으로 다음단계에서의 성능 향상을 위해 분류 단계에서 사용자의 이전 피드백 행동을 모두 히스토리(history)로 모두 기억시켜 놓고 다음 단계를 위한 가중치 학습을 위해 사용하도록 한다. 히스토리를 사용함으로써 제안하는 알고리즘은 사용자의 주관적 의도를 보다 정확하게 파악 할 수 있을 뿐만 아니라 학습을 위해 이전 단계만을 사용 했을 때 발생할 수 있는 성능 감소를 막을 수 있다. 본 논문에서는 Corel-photo CD에서 3000장의 자연 영상을 무작위로 추출하여 기존의 방법론들과 제안하는 방법론의 성능을 측정하여 본 논문에서 제안하는 방법론이 성능이 우수함을 증명하였다.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2003년도 The Fifth Asian Computational Fluid Dynamics Conference
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• pp.21-22
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• 2003

We perform two kinds of computer simulations on polydisperse hard-sphere systems; a molecular-dynamics simulation on atomic systems and a Brownian-dynamics simulation on colloidal suspensions. Analyses of the mean square displacement, the radial distribution function, and the pressure suggest that there exist three phase regions, a liquid phase region, a metastable phase region, and a crystal phase region, where the freezing and melting points are shifted to the values higher than in monodisperse case. It is also shown that the long-time behavior of colloidal suspensions is exactly the same as that of atomic systems.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -2
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• pp.851-854
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• 2000

Digital halftoning is a technique to make an equivalent binary image from scanned photo or graphic images. Low pass filtering characteristic of human visual system can be applied to get the effect of spatial averaging of local area consisted of black and white pixels for gray image. The overlapping of black dot decreases brightness and black dot is very sensitive to human visual system in the bright region. In this paper, for gray-level expression, only bright gray region in the color image is considered for blue noise mask (BNM) approach. To solve this problem, BNM with CMY dot is used for the bright region instead of black dot. Dot-on-dot model with single mask causes the problem making much black dot overlap, color distortion. Therefore approach with three masks for C, M and Y each is proposed to decrease pixel overlap and color distortion.

• 한국정밀공학회지
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• 제34권1호
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• pp.65-72
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• 2017

The goal of this paper is to investigate the effects of out-of-plane deposition angle on product characteristics of a UV photo-curing process. Specimens are manufactured from a commercialized UV photo-curing machine, the NOBEL V1.0. The influence of the out-of-plane deposition angle of the specimen on surface characteristics, including morphology of the sloped surface, pick-to-pick distance of convex region, and roughness of the sloped surface, is examined via the observation of the sloped surface. In addition, the influence of the radius of curvature of the specimen on the surface roughness of the sloped surface is evaluated. The effects of the out-of-plane deposition angle on impact strength of specimens are investigated via Izod impact experiments. Finally, we discuss the influence of the out-of-plane deposition angle on failure characteristics of specimens for impact loads.

• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제4권11호
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• pp.529-536
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• 2015

비사실적 렌더링(NPR; Non-Photorealistic Rendering)은 2차원 영상과 3차원 모델을 대상으로 하는 방법이 다르며 각각의 대상에 NPR을 적용하여 두 콘텐츠를 혼합하면 이질감이 나타나는 문제점이 있다. 본 논문에서는 3차원 객체와 영상에 있어서 각각의 대상에 카툰 및 스케치와 같은 비사실적 효과를 적용하여 조화롭게 혼합하는 기법을 제시한다. 제안 기법은 2차원 영상의 데이터를 분석하여 컬러 분포 특징을 얻고 이를 이용하여 실사 영상이나 3D 객체의 컬러 수를 줄인다. 단순화된 컬러맵과 윤곽선 에지 데이터로부터 비사실적 렌더링을 실시한다. 컬러맵 정보의 추출 및 적용 과정에서 자연스러운 장면 연출을 위해서 영상분할 과정이 필요하다. 그러나 영상분할 기법은 많은 연산을 필요로 한다. 특히 크기가 큰 입력에 대해서는 비사실적 렌더링에 많은 시간이 소요된다. 처리 시간이 많은 영상분할의 고속화를 위하여 GPU(Graphics Processing Unit)를 이용한 병렬 컴퓨팅을 할 수 있는 GPGPU(General-Purpose GPU)를 사용한다. GPGPU의 사용으로 알고리즘의 수행속도를 크게 개선하였다. 또한 영상분할 후 단순화된 컬러를 추출하여 일련의 컬러맵을 생성한 뒤 3D 객체에 NPR을 적용할 때 추출해낸 컬러맵을 적용하여 2차원 영상과 3차원 객채 간의 이질감을 줄이고 조화롭게 하였다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XII)
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• pp.143-144
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• 2003

$NaNO_3$ 와 urea 농도를 달리하며 S. Platensis 성장 실험을 진행한 결과 각각의 농도가 높아질수록 urea가 S. Platensis 성장에 저해작용이 큼을 알 수 있다.

• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 2002년도 제9회 학술 발표회 프로그램과 논문초록
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• pp.51-51
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• 2002

PpsR from the facultative photohetrotroph Rhodobacter sphaeroides is involved in repression of photo system gene expression. SDS-PAGE analysis showed that some portion of PpsR is oxidized so that intra- or inter-disulfide bond is formed between the two cysteins in each subunit. The disulfide bond was reduced by dithiothreitol and the binding activity to puc promoter region was increased.(omitted)