• 한국융합학회논문지
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• 제11권3호
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• pp.53-59
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• 2020

허베이 스피리트호 기름유출사고와 같은 해양 유류유출사고에서 잘못된 초기대응은 경제 손실뿐만 아니라 생태계에 큰 피해를 입힌다. 하지만 다양한 변수가 존재하는 해양에서 유출유의 움직임을 예측하는 것은 매우 힘든일이다. 이를 해결하기 위해서 뜰개 데이터를 활용해서 바다위의 부유물의 이동을 연구하는 기존 연구인 입자예측을 확장하여 면단위로 예측을 하는 유출유 예측 가시화를 진행하였다. 해양 데이터 포맷인 HDF5에서 특정 위치의 해류, 풍속 데이터를 양선형 보간법을 이용해 추출한 뒤, 수많은 점들의 이동을 입자예측하여 그 결과를 폴리곤 및 히트맵을 이용해 가시화 하였다. 또한 뜰개데이터의 문제점인 데이터 부족과 유출유와 움직임이 다른 점을 해결 하기 위해 유출유로부터 입자 데이터를 얻어낼 수 있는 유출유 입자 매칭 알고리즘을 제안한다. 유출유 입자 매칭 알고리즘은 면단위 유출유의 모습을 입자화 하여 입자의 움직임을 추적하는 알고리즘이다. 주성분 분석을 이용하여 문제를 분할하고, 유출유의 이동 거리의 분산이 최소화 되는 지점으로 유전알고리즘을 이용해 매칭하였다. 유출유 가시화 결과 데이터로 검증한 결과 주성분 분석과 유전알고리즘을 이용한 입자매칭 알고리즘이 가장 성능이 뛰어난 것을 확인할 수 있었으며, 평균 데이터 오차는 3.2%로 의미있는 연구임을 확인하였다.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2003년도 The Korea-Japan Joint Symposium
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• pp.49-50
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• 2003

In this paper, we describe a precise relationship between measured mechanical properties of cloth and the particle model. T he proposed cloth model is compared with the tablecloth drape, furthermore it is validated by the visualization of cloth 3-D drapeability.

• 한국연소학회지
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• 제15권4호
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• pp.65-73
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• 2010

In order to provide fundamental information for developing reaction model in the practical blended coal power plants, effects of particle size and blending ratio on combustion characteristics and thermal reaction in co-firing with bituminous and sub-bituminous coals were experimentally investigated using a TGA and a laboratory-scale burner. Characteristic parameters including ignition, burnout temperature and activation energy were determined from TG and DTG combustion profiles. Distributions of flame length and mean particle temperature were investigated from the visualization of flames in slit-burner system. As coal particle size decreased and volatile matter content increased, characteristic temperatures and activation energy decreased. The ignition/burnout characteristics and activation energy are linearly influenced by a variation in particle size and blending ratio. These results indicated that the control of the coal blending ratio can improve the combustion efficiency for sub-bituminous coals and the ignition characteristics for bituminous coals.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2004년도 Proceedings of 2004 Korea-Japan Joint Seminar on Particle Image Velocimetry
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• pp.119-124
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• 2004

Experimental study was conducted to characterize the flow effect of particle migration in a microchannel which can be used to deliver small amount of liquids, drugs, biological agents and particles in microfluidic devices. Fluorescent particles of $1\{mu}m$ diameter were used to obtain velocity profiles of the fluid in which large particles of $10\{mu}m$ diameter were suspended at different volume fraction of 0.6 and $0.8\%$. Measurements were obtained by using micro-PIV system which contains a Nd:YAG laser with a light of 532-nm wavelength, an inverted epi-fluorescent microscope and a cooled CCD camera to record particle images. The volume fraction of $\phi$ and the particle Reynolds number $Re_p$Rep were used as a parameter to assess the influence of the velocity profile of the suspensions. To expect the slip velocity between the particle and fluids, experiments were carried out at low volume fraction. It was shown that the velocity profile was not influenced by Rep but influenced by the volume fraction, which is in similar trend with the previous study.

• 한국멀티미디어학회논문지
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• 제19권2호
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• pp.224-232
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• 2016

The methodology to visualize the shape of blood vessel and its blood flow have been attracting as a very interesting problem to forecast and examinate a disease in thrombus precursor protein. May previous visualization researches have been appeared for designing the blood vessel and also modeling the blood flow using a doppler imaging technique which is one of nondestructive testing techniques. General visualization methods are to depict the blood flow obtained from doppler effects with fragmentary stream lines and also visualize the blood flow model using volume rendering. However, these visualizeation techniques have the disadvantage which a set of small line segments does not give the overall observation of blood flows. Therefore, we propose a visualization system which reconstruct the continuity of the blood flow obtained from doppler effects and also visualize the blood flow with the vector field of blood particles. This system will use doppler phase difference from medical equipments such as OCT with low penetration and reconstruct the blood flow by the curvature estimation from vector field of each blood particle.

• 한국주거학회논문집
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• 제26권4호
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• pp.55-62
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• 2015

The international concern on the inhalable fine dust is continuing to increase. In addition to the toxic properties of the fine dust itself, it can be more dangerous than other environmental factors since the dust pollution is hard to be detected by human sense. Although the information on outdoor air condition can be acquired easily, the indoor dust concentration is another problem because the indoor air condition is influenced by the architectural environment and human activity. It means occupants may be exposed to indoor dust pollution over a long period without being aware. Therefore the indoor dust concentration should be measured separately and visualized as an intuitive information. By visualizing, the indoor dust concentration in each space can be recognized practically in compare with the degree of pollution in adjacent spaces. Besides the visualization outcome can be used as base data for related research such as an analysis of the relation between indoor dust concentration and architectural environment. Meanwhile, with the development of network and micro sensing devices, it became possible to collect wide range of indoor environment data. In this regards, this paper suggests a system for visualization of indoor dust concentration and demonstrates it on an actual space.

• 한국가시화정보학회지
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• 제10권3호
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• pp.30-36
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• 2012

We are planning to construct a scaled-down moderator facility to simulate the CANDU-6 moderator circulation phenomena during steady state operating and accident conditions. In the present work a preliminary experiment using a 1/40 scaled-down moderator tank has been performed to investigate the anticipated problems of the flow visualization and measurement in the planning scaled-down moderator facility. We shortly describe CFD analysis result for the 1/40 scaled-down test model and the flow measurement techniques used for this test facility under isothermal flow conditions. The Particle Image Velocimetry (PIV) method is used to visualize and measure the velocity field of water in a transparent Plexiglas tank. Planar Laser Induced Fluorescence (PLIF) technique is used to evaluate the feasibility of temperature field measurement in the range of $20-40^{\circ}C$ of water temperature using an one-color method.

• 대한기계학회논문집B
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• 제25권12호
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• pp.1684-1691
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• 2001

Electrorheological fluids(ERFs) show a rapid and reversible increase in apparent viscosity by applied electric field. It is called the electrorheological effect (ER effect). The reason for ER effect is the induction of an electric dipole in each particle, leading to the formation of clusters in the direction of the field, which resist fluid flow. Generally, the behavior of ER fluids has been modeled on those of Bingham fluids. But there are some differences between Bingham fluids and ER fluids. The visualization of ER fliuds are presented and ER effects by the forming, growing and breaking of clusters are discussed. In the low shear rate area, the pressure drop is measured by a pressure sensor and the formation of ER particles is visualized by video camera. The reason for the nonlinear behavior of ER fluids at low shear rate is explained through results of visualization. As result, the behavior of ER fluids is nonlinear at low shear rate with overshoot area because it is different to from the clusters according to the strength of electric field. The gap of electrodes becomes narrow because of the cluster layer occurrence near to electrodes in any conditions.

• 한국가시화정보학회지
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• 제18권1호
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• pp.50-58
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• 2020

This paper presents flow characteristics of a sweeping jet issued by a feedback-free fluidic oscillator. Overall flow characteristics of feedback-free sweeping jet (FFSJ) were analyzed using flow visualization. The feedback-free sweeping jet has a sinusoidal external flow pattern. The oscillating frequency of the FFSJ is three times higher than that of a conventional sweeping jet at the same Reynolds number. Flow structure and turbulence characteristics were investigated using time-resolved particle image velocimetry (TR-PIV). In instantaneous velocity fields, the flow did not stay at ends but changed the direction continuously in contrast to the conventional sweeping jet. Velocity distributions at each plane which were extracted from mean velocity field has Gaussian distribution, which is similar with a circular jet. The sweep angles were constant as 45° at all Reynolds numbers in the high flow rate regime.

• 대한공간정보학회지
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• 제24권1호
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• pp.99-107
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• 2016

대한민국은 화산재해로부터 안전한 지역으로 알려져 왔다. 그러나 최근의 관측 결과들은 한반도 최 북 단에 위치한 백두산이 더 이상 휴화산이 아님을 보여주고 있다. 백두산 화산이 폭발한다면 남한지역에서는 화산재에 의한 다양한 피해가 예상된다. 특히 공중의 화산재는 운항되는 비행기의 계기판 및 엔진을 마비시킴으로써 대형 항공사고를 유발할 수 있다. 따라서 화산재의 삼차원 확산을 예측하여 화산재가 있는 항로를 비행할 것으로 예상되는 비행기 운항을 중지시키는 것이 매우 중요하다고 할 수 있다. 본 논문에서는 화산재 확산 예측결과의 삼차원 가시화 기법을 다룬다. 우선 화산재 확산 예측 데이터의 취득에 대하여 소개한다. 확산 예측 데이터는 화산재 확산 시뮬레이션 프로그램인 Fall3D를 이용한다. 다음으로 세 가지 화산재 확산 예측결과의 가시화 기법을 제안한다. 첫 번째 기법은 '공중의 큐브' 방식으로 화산재의 입자 농도별로 다른 색을 가진 반투명 큐브를 공중에 배치하는 방식이다. 두 번째 기법은 '큐브안의 큐브'방식으로 '공중의 큐브' 방식을 개선하여 농도의 정도에 따라 큐브의 분할 정도를 달리하여 배치하는 방식이다. 마지막 방식은 '반투명 화산재 평면' 기법으로 화산재 농도를 가지고 있는 레이어 들을 적층하고 투명효과를 적용하는 방식이다. 본 논문에서 제시한 방법을 기반으로 사용자는 목적에 맞는 방식대로 화산재 확산 예측 결과를 삼차원 가시화 할 수 있을 것이다.