• Title/Summary/Keyword: Non-moving particle

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A Study on the Dynamic Painterly Stroke Generation for 3D Animation (3차원 애니메이션을 위한 회화적 스트로크의 동적 관리 기법)

  • Lee, Hyo-Keun;Ryoo, Seung-Taek;Yoon, Kyung-Hyun
    • Journal of Korea Multimedia Society
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    • v.8 no.4
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    • pp.554-568
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    • 2005
  • We suggest the dynamic stroke generation algorithm that provides frame-to-frame coherence in 3D non-photorealistic animations. We use 3D particle system to eliminate the visual popping effect in the animated scene. Since we have located particles on the 3D object's surface, the coherence is maintained when the object or the camera is moving in the scene. Also, this algorithm maintains the coherence when camera is zooming in/out. However, the brush strokes on the surface also zoom in/out. This result(too large or too small brush strokes) can not represent hand-crafted brush strokes. To remove this problem, we suggest stroke generation algorithm that dynamically maintains the number of brush stroke and its size during camera zoom in/out.

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On the Viscous Flow Around Breaking Waves Generated by a Submerged Cylinder(Part 1 : Wave Pattern and Surface Pressure) (몰수실린더에 의하여 생성되는 쇄파주위 점성유동의 고찰 (제1부 : 파형 및 압력분포))

  • B.S. Hyun;Y.H. Shin
    • Journal of the Society of Naval Architects of Korea
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    • v.37 no.1
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    • pp.82-90
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    • 2000
  • An experimental study has been carried out at circulating water channel to investigate the non-breaking and breaking waves generated by a submerged circular cylinder steadily moving under the free surface. Free surface profiles and pressure distributions on cylinder surface were measured at various submerged depths of cylinder. They were complemented by the measurements of velocities, head losses and turbulence intensities in the wakes of body and "breaker". Part 1 of this three-part paper describes the experimental arrangement and the patterns of wave profile and pressure distribution at various depths of submergence. These databank contributions are of special interest in traditional ship hydrodynamics. In Part 2, special focuses are made to elucidate the viscous and turbulent aspects of flow field. Finally Part 3 will deal with the visualization of instantaneous vortical flow to study the mutual interaction between vorticies shedded from the free-surface and the cylinder using a Particle Image Velocimetry.

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Distribution and Characteristics of Microorganisms Associated with Settled Particles During Asian Dust Events (황사 발생 기간 낙하먼지에 포함된 미생물의 분포 및 특성)

  • Koh, Ji-Yun;Jang, Chan-Gook;Cha, Min-Ju;Park, Kyo-Nam;Kim, Min-Kyu;Kim, Jong-Seol
    • Korean Journal of Microbiology
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    • v.48 no.2
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    • pp.134-140
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    • 2012
  • Asian dust storms originating in the arid desert of China and Mongolia usually occur from late winter through spring, and more than one million tons of dust per year is transported to the Korean Peninsula by the prevalent westerly winds. We supposed that these dust particles could include bioaerosols and act as carriers of microorganisms. In order to clarify the dynamics of microorganisms moving with these particles, the concentration and composition of microorganisms associated with settled particles were compared between samples collected during Asian dust events and those under non-dust periods. From February to April 2008, settled dust particles were collected at one location in Ulsan using rainfall meter of 200 mm diameter. During this period, there was one Asian dust event in Ulsan. The bacterial concentrations were higher in samples collected during Asian dust event than those under non-dust period, whereas fungal concentrations were rather similar regardless of the Asian dust event. We analyzed 16S rRNA gene sequences of 45 bacterial isolates obtained from the settled particle samples. These isolates belonged to either genus Bacillus or genus Streptococcus and were tentatively identified as B. amyloliquefaciens, B. aryabhattai, B. atrophaeus, B. licheniformis, B. megaterium, B. methylotrophicus, B. pumilus, B. sonorensis, B. subtlis, B. vallismortis, S. epidermidis, and S. succinus. In cases of fungal isolates, genera such as Mucor, Alternaria, Cladosporium, and Aspergillus were tentatively identified from samples collected at both Asian dust and non-Asian dust periods. It appears that endospore-forming bacteria such as Bacillus sp. rather than fungal spores are more likely to be associated with Asian dust particles.

Change in the Concentration of Fine Particles, Temperature, and Relative Humidity as Affected by Different Volume Ratios of Interior Greening in Real Indoor Space (실내녹화 부피비율이 실공간의 미세분진농도, 온도 및 상대습도에 미치는 영향)

  • Ju, Jin-Hee
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.13 no.2
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    • pp.1-7
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    • 2010
  • The study objective was to compare the interior greening volume ratios for the change in concentration of fine particle, temperature and relative humidity, and to identify the level of interior landscape volume ratio as a suitable condition to achieve the desired indoor properties. Plants were moved into a room (88m3) randomly. After moving, the volume ratio of the interior greening level was set at 0%, 1%, 2% and 3%. The concentration of fine particles was measured with a mini-volume portable air sampler (Air Metrics, USA). The temperature and relative humidity were recorded with a digital sensor (Kiwi-LTH, USA) during the experiment under different volume ratios with three replications. 1. The results of the change in concentration of the fine particles revealed a trend towards an increased volume ratio of interior greening with decreasing concentration of fine particles, compared to non-plants (0%). The concentration of fine particles at volume ratios of 0%, 1%, 2% and 3% was 55ug/$m^3$, 233ug/$m^3$, 40ug/$m^3$ and 30ug/$m^3$, respectively. 2. The change in temperature, at volume ratios of 0%, 1%, 2% and 3% was $21.2^{\circ}C$, $17.4^{\circ}C$, $16.7^{\circ}C$ and $18.9^{\circ}C$, respectively, in near interior greening, and $22.1^{\circ}C$, $18.7^{\circ}C$, $18.4^{\circ}C$ and $20.5^{\circ}C$ respectively, at a distance of 3m from the interior greening. These study results suggested that temperature was affected by volume ratio and distance from the interior greening. 3. The relative humidity, at volume ratios of 0%, 1%, 2% and 3% was 34.2%, 32.5%, 36.7%, and 46.9%, respectively, in near interior greening, and 31.2%, 26.9%, 31.4% and 38.3%, respectively, at a distance of 3m from the interior greening. With increasing volume ratio of interior landscape, there were positive and significant results between the distance difference and the relative humidity more than temperature.

An investigation on the insulation characteristics of $SF_6$ mixtures gas under uniform and non-uniform electric field (평등/불평등 전계에서의 $SF_6$혼합된 가스의 절연파괴특성 연구)

  • Lee, Sang-Hwa;Lee, Young-Jo;Ahn, Hee-Sung;Jeong, Seung-Young;Koo, Ja-Yoon
    • Proceedings of the KIEE Conference
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    • 2007.07a
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    • pp.1397-1398
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    • 2007
  • 본 연구는 $SF_6$와 Dry-air(건조공기), $N_2$, $CO_2$ 가스가 혼합된 절연매체의 절연 특성과 부분방전 특성 연구를 기초실험용 쳄버와 70kV급 GIS mock up을 이용하여 교류전압을 인가하여 실험이 수행되었다. 전자의 경우, Sphere gap 및 Needle/Plate 전극시스템을 이용하여 순수 $SF_6$가스와 Dry-air, $N_2$, $CO_2$ 가스들의 절연내력을 비교하고, 챔버의 압력을 5기압으로 유지한 상태에서 Dry-air, $N_2$, $CO_2$$SF_6$가스의 혼합비를 변화시키면서 절연내력이 측정되었다. 후자의 경우, 기초실험에서 도출된 $SF_6$가스와 Dry-air, $N_2$, $CO_2$의 최적의 혼합비율을 선택한 후, 방전 개시전압과 부분방전 양상을 순수 $SF_6$가스의 결과와 비교분석하기 위한 실험을 수행하였다. 이를 위하여 GIS 사고의 주요원인이 되는 결함들, 즉 Protrusion, Floating, Free moving particle 들을 인위적으로 모의하여 Mock up 내부에 설치하고 내부 압력을 5기압으로 유지한 상태에서 수행되었다. 전자의 경우, $0.5{\sim}5$ 기압 범위 내에서 Dry-air, $N_2$, $CO_2$ 압력을 변화시켰을 때 절연내력은 전극시스템에 무관하게 순수 $SF_6$가스의 결과치의 Dir-air $47{\sim}51%$, $N_2\;48{\sim}61%$, $CO_2\;47{\sim}60%$ 정도이다. 또한 챔버 압력이 5기압인 상태에서 Dry-air, $N_2$, $CO_2$가 80% 혼합된 절연매체는 순수 $SF_6$가스 절연내력의 80%이상의 절연내력을 가지고 있다. 후자의 경우, 인가전압을 고정 시켰을 때, 부분방전 패턴과 방전크기는, 순수 $SF_6$가스와 Dry-air 가 80% 혼합된 절연매체는 동일한 패턴과 방전크기를 나타내고 있다. 이러한 결과를 근거로, 가스 압력이 5기압에서 운전되는 전력기기의 절연매체로서 혼합가스를 사용할 경우, $SF_6$가스와 Dry-air, $CO_2$, $N_2$ 가스들의 혼합비는 2:8정도가 적절한 것으로 제안한다.

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