• Journal of Korea Water Resources Association
• /
• v.34 no.6
• /
• pp.605-615
• /
• 2001

SMAC method, one of the numerical simulation techniques, is modified from the original MAC method for the time-dependent variation of fluid flows. The Navier-Stokes equations for incompressible time-dependent viscous flow is applied, and marker particles which present the visualization of fluid flaws are used. In this study, two-dimensional numerical simulations of the water column collapse are carried out by SMAC method, and the simulation results are compared with Martin and Moyce's experimental data and result of the MPS method. A good results are obtained. This numerical simulation could also be applied to the breaking phenomenon of hydraulic structures such as dam break.

• Communications for Statistical Applications and Methods
• /
• v.16 no.2
• /
• pp.277-286
• /
• 2009

Image registration is a process to establish the spatial correspondence between images of the same scene, which are acquired at different view points, at different times, or by different sensors. In this paper, we introduce a robust brain registration technique for correcting the difference between two temporal images by the different coordinate systems in MR and CT image obtained from the same patient. Two images are registered where this measure is minimized using a modified conditional entropy(MCE: Modified Conditional Entropy) computed from the joint histograms for the intensities of two given images, we conduct the rendering for visualization of 3D volume image.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.21 no.6
• /
• pp.57-63
• /
• 2017

In this study, the fundamental test for drag reduction is carried out by using a plasma generator. Fundamental test setup is constructed of visualization and drag measurement system. The schlieren technique is used to visualize the plasma counterflow in supersonic flow. The penetration of the plasma jet and the change of the flow structure are observed through visualization results. Load cell is used to confirm possibility of drag reduction. Results show that drag was reduced by 6.2% using plasma jet in supersonic flow.

• Journal of the Korean Society of Visualization
• /
• v.22 no.2
• /
• pp.74-81
• /
• 2024

Accurate tissue temperature monitoring during clinical procedures, such as laser therapy or surgery, is crucial for ensuring patient safety and treatment efficacy. Noninvasive techniques are essential to prevent tissue disturbance while providing real-time temperature data. However, current methods often struggle to accurately measure temperature at various depths within the skin, which is essential to avoid damage to surrounding healthy tissues due to excessive heat. In response to this challenge, we developed a confocal imaging system that utilizes the laser speckle imaging (LSI) technique for precise depthwise temperature monitoring. LSI uses laser light scattering to capture subtle changes in speckle patterns on the skin's surface due to temperature fluctuations within the tissue. By analyzing these changes, LSI enables accurate depth-resolved temperature measurements. This technique enhances the precision and safety of medical procedures, offering significant potential for broader clinical applications, improved patient outcomes, and better thermal management during interventions.

• 한국공간정보시스템학회:학술대회논문집
• /
• 2005.05a
• /
• pp.97-100
• /
• 2005

3차원 공간정보는 u-Korea, 전자정부, 유비쿼터스, LBS등의 기반 인프라 및 3차원 그래픽 처리기술, 가상현실 기술 등의 종합적으로 적용되는 고부가가치 통합 기술로 필요성이 부각되고 있다. 본 연구에서는 컴퓨터 그래픽스 분야에서 많이 적용되고 있는 공개 그래픽 라이브러리인 OpenGL(Open Graphics Library) 기반의 3D-GIS 가시화 어플리케이션 아키텍쳐를 중심으로 렌더링 기법을 분석하고자 한다. 한편 본 연구의 실험은 Visual Studio.NET환경에서 3D-GIS 모델 Prototype을 구현하여 수행하였으며 향후 실시간 모바일 3D-GIS 렌더링을 위한 기반 기술로 적용될 수 있는 OpcnGL-ES의 확장 가능성을 검토하고자 하였다.

• Journal of the Korean Society for Precision Engineering
• /
• v.12 no.7
• /
• pp.53-65
• /
• 1995

입자화상 처리기법은 유체역학 분야의 정량적 유동가시화에 있어서 중요한 역할을 하고 있다. 회전 유동의 측면 사진을 찍을 때, 측정부의 볼록면 때문에 그 영상에서 광학적 변형이 일어나게 된다. 이러한 변형은 측정부의 형상은 물론 회전유동의 방향에 의해서도 큰 영향을 받는다. 정확한 유동장을 얻기 위해서 이러한 변형이 적절한 방법에 의하여 교정된다. 교정한 실험 데이터를 수치해석 결과와 비교해 보면 정량적으로 잘 맞는 것을 알 수 있다.

• Journal of the Korean Society of Visualization
• /
• v.3 no.2
• /
• pp.14-20
• /
• 2005

내연기관 연소는 난류유동, 분무, 연소, 열전달의 복합적인 현상으로서 열역학적 해석이 주류를 이루어 왔으나 컴퓨터의 발전에 따라 효율 개선과 공해 저감을 목표로 전산유체해석 기법이 적극적으로 도입되고 있다. 내연 기관 연소의 근간을 형성하는 난류 연소 모델링의 기본 개념으로서 가솔린엔진에서의 예혼합연소와 디젤엔진에서의 확산연소에 대한 영역조건평균(zone conditional averaging) 모델과 조건평균닫힘(conditional moment closure) 모델에 대해 설명하였으며 $NO_x$와 soot 예측에 대한 적용과 엔진응용 사례를 소개하였다.

• 한국가시화정보학회:학술대회논문집
• /
• 2004.11a
• /
• pp.108-111
• /
• 2004

Laser induced incandescence and laser induced fluorescence techniques have been investigated to measure the concentrations of soot and PAH, respectively. The Nd:YAG and dye lasers were used to form a sheet beam, and its wavelength were modulated to obtain a optimized signals of soot and PAH. Results showed that the relative size groups of soot and PAH can be measured by using our laser techniques.

• Proceedings of the KSEEG Conference
• /
• 2001.05a
• /
• pp.94-101
• /
• 2001

이 연구에서는, PC 모니터와 3차원 가시화 장치인 Shutter Glasses를 이용하여 실시간 (real time)으로 3차원 영상을 구현할 수 있는 방법을 개발하였다. VRML (Virtual Reality Model Language)을 이용하여 간단한 입체 게임을 구성한 후, 3명의 학생을 대상으로 인터넷을 통하여 실시간으로 실험한 결과, PC에서 동기화 이 중 가시화 방식으로 생성한 3차원 입체영상은 모니터의 전후 방향으로 돌출되거나 함몰되는 현상을 나타냈다. 따라서, 실시간으로 3차원 영상을 구현할 수 있는 기초 이론과 방법을 개발할 수 있었다.

• Journal of Korea Multimedia Society
• /
• v.14 no.3
• /
• pp.339-347
• /
• 2011

As the volume visualization has been applied to render medical datasets, there has been a requirement to produce high quality images. Even though nice images can be generated by using previous linear filter, high order filter is required for better images. However, it takes much time for high order resampling, so that, overall rendering time is increased. In this paper, we perform high quality volume visualization using the cardinal interpolation. By enabling the empty space leaping which reduces the number of resampling, we achieve the efficient visualization. In detail, we divide the volume data into small blocks and leap empty blocks by referring the upper and lower bound value for each block. We propose a new method to estimate upper and lower bound value of for each block. As the result, we noticeably accelerated high quality volume visualization.