• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.497-502
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• 2001

Three-dimensional natural convection from a discrete flush-mounted circular heat source on the bottom of a cubic enclosure was studied by using a holographic interferometric tomography. The heat source was located at the off-center of the bottom plate so that three-dimensional temperature field can be achieved. A set of multidirectional holographic interferogram was recorded by employing a double-reference beam, double-exposure holographic technique in order to eventually reconstruct the temperature fields. The recorded interferometric data appear good enough to be further processed to extract optical pathlength data from them and finally reconstruct the temperature fields. A complete analysis of the temperature fields including the field reconstructions and comparison with thermocouple measurements is underway and will be reported shortly.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2001년도 Proceedings of 2001 Korea-Japan Joint Seminar on Particle Image Velocimetry
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• pp.100-107
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• 2001

A simple new technique of particle depth position measurement, which can be applied for three-dimensional velocity measurement of fluid flows, is proposed. Two color illumination system that intensity is encoded as a function of z-coordinate is introduced. A calibration procedure is described and a profile of small sphere is detected by using the present method as preliminary test. Then, this method is applied to three-dimensional velocity field measurement of simple flow fields seeded with tracer particles. The motion of the particles is recorded by color 3CCD camera. The particle position in the image plane is read directly from the recorded image and the depth of each particle is measured by calculation of the intensity ratio of encoded two color illumination. Therefore three-dimensional velocity components are reconstructed. Although the result includes to some extent error, the feasibility of the present technique for three-dimensional velocity measurement was confirmed.

• 한국멀티미디어학회논문지
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• 제15권10호
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• pp.1264-1272
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• 2012

3차원 볼륨렌더링 방법은 인체의 외형뿐만 아니라 내부의 모습도 투과하여 보여줄 수 있기 때문에 의료영상 분야에서 널리 사용된다. 기존의 의료영상 장비는 볼륨렌더링 방법을 이용하여 다양한 3차원 영상을 제공하고 있다. 최근 의료영상 분야에서는 휴대성의 장점을 가진 스마트 기기를 도입함으로써 기존 의료영상 분야의 결과물을 의사와 환자들 사이에서 소통이 원활하게 하려는 연구가 활발히 진행되고 있다. 본 논문에서는 비교적 저 사양인 휴대용 스마트 기기에서 3차원 볼륨데이터를 가시화하기 위하여 2차원 텍스쳐를 활용하는 방법을 제안하고 다양한 2차원, 3차원 진단영상을 제공하는 휴대용 의료영상 가시화 시스템을 제안한다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.535-540
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• 2000

The objective of the present study is to visualize the pulsatile flow fields by using three-dimensional computer simulation and the PIV system. A closed flow loop system was built for the steady and unsteady experiments. The Harvard pulsatile pump was used to generate the pulsatile pressure and velocity waveforms. Conifer powder as the tracing particles was added to water to visualize the flow field. Two consecutive particle images were captured by a CCD camera for the image processing. The cross-correlation method in combination with the moving searching area algorithm was applied for the image processing of the flow visualization. The pulsatile flow fields were visualized effectively by the PIV system in conjunction with the applied algorithm. The range validation and the area interpolation methods were used to obtain the final velocity vectors with high accuracy. The finite volume predictions were used to analyze three-dimensional flow patterns in the bifurcation model. The results of the PIV experiment and the computer simulation are in good agreement and the results show the recirculation zones and formation of the paired secondary flow distal to the apex of the bifurcated model. The results also show that the branch flow is pushed strongly to the inner wall due to the inertial force effect and helical motions are generated as the flow proceeds toward the outer wall.

• Journal of Mechanical Science and Technology
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• 제15권12호
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• pp.1750-1756
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• 2001

Three-dimensional and unsteady flow analysis is a practical target of high performance computation. As recently advances of computers, a numerical prediction by the large eddy simulation (LES) are introduced and evaluated for various engineering problems. Its advanced methods for the complex turbulent flows are discussed by several examples applied for aerodynamic designs, analysis of fluid flow mechanisms and their interaction to complex phenomena. These results of time-dependent and three-dimensional phenomena are visualized by interactive graphics and animations.

• 한국의류산업학회지
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• 제24권4호
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• pp.443-450
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• 2022

This study developed a three-dimensional helmet mold design software that can design helmets for treating the infant plagiocephaly (flat head syndrome) using three-dimensional head scan data. For this, the three-dimensional head data of sixth SizeKorea body measurement project as well as the data produced by a head modeling software were used to prepare the head shape data of plagiocephaly patients. A total of 14 landmarks and 10 dimensions of heads required for helmet mold shape design and plagiocephaly diagnosis were automatically measured using an anthropometric analysis software. Using the software developed in this study, plagiocephaly can be diagnosed not only visually by three-dimensional head data visualization but also quantitatively by calculating the medically defined indices such as cranial index, which measures the proportions of the head, and the cranial vault asymmetry index, which measures the asymmetry of the head. The basic shape of the helmet mold was automatically generated based on the head scan data. Additionally, it is possible to fine tune the shape of the mold to reflect individual characteristics by using a free form deformation technique. Finally, the designed helmet mold was converted into the data that can be printed on a three-dimensional printer for generating the actual prototype.

• 한국컴퓨터그래픽스학회논문지
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• 제3권2호
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• pp.27-34
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• 1997

3 차원 영상 모델링은 자동 시각적 검사와, 비파괴 검사분야에서 절실히 요구되고 있는 연구 분야이다. 또한 그것은 생의학연구, 의료, 수술계획과 정교성이 요구되는 중대한 수술 (안면 절개) 등에 매우 유용하다. 영상처리 및 분석 기술은 3 차원 의료 영상 정보의 질올 높여 주는데, 의료정보를 정확하고 빠르게 분석하는 일은 용이하지 않다. 본 논문에서는 향상된 3 차원 의료영상의 가시화를 위하여 사면체 분할법에 의한 모델링 방법을 제안한다. 이 방법에서는 트라이 베리에이트 구간별 선형 보간법이 구축된 사면체영역에 걸쳐 적용된다. 그리고, 등면, 색채 윤곽, 슬라이싱 등 가시화 방법들도 논의된다. 이것은 마칭큐브스 알고리즘으로 인해 제기되는 불확실한 경우가 발생하지 않고, 자료 감축의 효과도 가져올 수 있으므로 보다 정확하고 빠른 의료정보 분석에 기여할 수 있을 것으로 사료된다. 그리고, 자료 감축으로 인한 정확도의 감소가 발생할 경우에는 최소제곱을 바탕으로 한 사면체 세분할을 사용하여 보완할 수 있을 것으로 기대한다.

• 한국가시화정보학회지
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• 제11권3호
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• pp.5-11
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• 2013

It is of great importance to obtain the uniform layer thickness in the multi-layer co-extrusion processes. In the present study, the three-dimensional numerical simulation was carried out using the open source code named OpenFOAM(R) to understand the flow characteristics in the multi-layer die. In this numerical study, Multi-thin-layers were successfully computed depending on the number of repeating units. The generation mechanism for the multi-layer was numerically verified by the flow simulation and visualization in the co-extrusion die using OpenFOAM(R). The results suggested that the multi-layer has a divided and folded mechanism similar to the stretching and folding in the chaotic flow.

• 한국가시화정보학회지
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• 제9권3호
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• pp.44-50
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• 2011

In this study, we propose a method for characterizing fluid-mechanical properties of a fluid surface, such as surface dilatational and shear viscosity, by matching the flow visualization and the numerical simulation for a Stokes flow in a three-dimensional cavity. The surface flow is driven by shear stress exerted on the free surface by an external gas flow. The external gas flow is simulated by using a commercial code, while the Stokes flow is calculated by an in-house code. We have found that the surface flow is very sensitive to the surface tension and other properties. The qualitative feature of the surface flow can be reproduced by the parameter tuning.

• 한국가시화정보학회지
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• 제21권2호
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• pp.72-82
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• 2023

Effective thermal management in a battery electric vehicle (BEV) is crucial for reducing energy consumption and maximizing driving range in cold climates. Consequently, original equipment manufacturers are actively investing in the development of local heating systems. Visualizing occupant thermal behaviors or comfort can readily provide valuable insights that would substantially impact the design and control strategies of such microclimate systems. This study uses MATLAB for three-dimensional visualization of human thermal psychology. The developed program enables qualitative assessment of occupant comfort in BEVs.