• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.2
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• pp.41-47
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• 2017

By using liquid and gaseous nitrogen as simulants, effects of pintle opening distance and simulant supplying condition on spray from pintle injector were investigated qualitatively. The experiment was performed by fixing the liquid supply pressure and varying the opening of the pintle and the supply pressure of gaseous nitrogen. Shadowgraph method with CCD camera was used for image visualization, and the differences of liquid-gas spray were compared by image post processing. In case of liquid nitrogen single injection, as the opening distance was increased, the injection speed was decreased. Therefore, the end of liquid sheet were converged to the center of spray. In the case of liquid nitrogen/Gaseous nitrogen spray, although shadowgraph images look similar to each other, It is shown that it can be analysed by image post processing.

• Journal of the Korean Society of Visualization
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• v.3 no.2
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• pp.3-13
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• 2005

The optical patterantor provides the high resolution and quantitative information of the spray. Fuel distribution and Sauter Mean Diameter (SMD) can be measured from fluorescence and Mie-scat-tering images. To correct the attenuation of the laser beam and signal in dense spray region, the method to find the geometric mean of the signal intensities obtained from two cameras was evaluated and verified in a solid-cone spray. In high pressure environment, the increased number density of the droplets cause multiple scattering. The optical patternation technique using a laser beam instead of a laser sheet was applied to minimize the multiple scattering problem. The pattern of a coaxial spray was changed from hollow-cone to solid-cone shape, and the spray angle was reduced as the ambient pressure increased from 0.1 to 4.0 MPa.

• 한국HCI학회:학술대회논문집
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• 2007.02a
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• pp.713-718
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• 2007

본 논문에서는 실시간적인 요소와 높은 경험의 질을 요구하는 다자간 협업 환경에서 고해상도 비디오를 제공하기 위하여, 무손실과 저지연, 저비용의 특징을 갖는 비압축 HD 비디오를 처리할 수 있는 '비압축 HD 비디오 전송 응용' (Scalable Video Tool)을 구현하여 초고해상도 디스플레이를 위한 비압축 HD 가시화 서비스'를 구성한다. Scalable Video Tool (SVT)은 Microsoft 사의 Direct Show를 기반으로, 비압축 HD 카메라와 DV 카메라, WebCam의 영상도 실시간으로 처리가 가능하다. 초고해상도 디스플레이에 고해상도 비디오와 이미지 가시화를 지원하는 SAGE(Scalable adaptive graphics environment)[2]와 SVT를 연동하여 다자간 협업 환경에서 다양한 형태의 고해상도 비디오와 그래픽스 자료를 공유할 수 있는 시스템을 구성한다. 본 논문의 마지막에서는 $5{\times}11$의 격자 형태로 구성된 타일드 디스플레이 (Tiled Display)를 이용하여 제안된 시스템을 검증한다.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04a
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• pp.629-631
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• 2003

대부분의 상용 CIS 소프트웨어에서는 시공간분석 결과를 2 차원상에 가시화 하거나 해당 분석결과를 단순히 출력해 주는 형태이다. 3차원상의 질의 볼륨에 대한 3차원 공간분석 또한 이론 및 실험적으로 많은 연구가 이루어져 왔으나, 3 차원상의 공간분석 결과 가시화 기능을 통합한 시스템은 아직까지 미흡한 실정이다. 본 논문에서는 3 차원상의 공간연산 및 3 차원에 시간속성을 부가한 4 차원 시공간 연산을 처리할 있는 4 차원 CIS 시스템을 소개한다. 제안된 기법은 2차원 수치지도와 3 차원 부가속성을 가진 데이터베이스를 이용하여 2 차원, 3 차원, 미디어 데이터간의 상호연계 및 통합된 가시화 프레임워크를 제공한다. 또한 가상세계 매핑기법을 이용하여 수작업에 의존한 별도의 이미지 프로세싱 과정 없이도 비디오상의 특정 프레임의 건물에 대한 속성질의 및 2D/3D 간의 상호 연계 기능을 제공할 수 있다.

• Journal of the Korea Computer Graphics Society
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• v.2 no.2
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• pp.61-68
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• 1996

In this paper we propose a new visualization technique to characterize qualitative information of a large DNA sequence. While a long DNA sequence has huge information, it is not easy to obtain genetic information from the DNA sequence. We transform DNA sequences into a polygon to compute their homology in image domain rather than text domain. Our program visualizes DNA sequences with colored random walk plots and simplify them k-convex hulls. A random walk plot represents DNA sequence as a curve in a plane. A k-convex hull simplifies a random work plot by removing some parts of its insignificant information. This technique gives a biologist an insight to detect and classify DNA sequences with easy. Experiments with real genome data proves our approach gives a good visual forms for long DNA sequences for homology analysis.

• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.227-231
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• 2014

• Journal of the Korea Computer Graphics Society
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• v.24 no.3
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• pp.21-31
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• 2018

We introduces a system that enables fast and effective visualization of natural disaster data such as typhoons, tsunamis, floods, and flooding to help make informed decisions in disaster situations. Data containing disaster information consists of a few hundred megabytes to many tens and hundreds of gigabytes, which can not be handled by a PC. This system was implemented in the form of a client-server based service to generate and output results from high-performance servers. The server in a built-in, high-performance cluster handles client requests and sends the result of visualization to the client. Clients can receive the results in any form of images, videos, or 3D graphic model by specifying a desired time frame, effectively viewing the results with a user-friendly GUI.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.10
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• pp.817-824
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• 2015

Experiments were carried out to investigate the flow and mass transfer characteristics of an orifice nozzle. Measurements of primary and suction flow rates, dissolved oxygen concentration, and electric power were obtained. Vertically injected mixed-jet images were captured by a direct visualization technique with a high speed camera unit. The mass ratio, volumetric mass transfer coefficient, and mass transfer performance were calculated using the measured data. As the primary flow pressure increases, the mass ratio decreases slightly, while the volumetric mass transfer coefficient and electric power increase. As the primary flow pressure increases and the mass ratio decreases, the mass transfer rate increases because of the fine bubbles and wider distribution of the bubbles.

• Journal of the Korean Society of Visualization
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• v.21 no.2
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• pp.83-90
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• 2023

The shape of an airfoil is a critical factor in determining aerodynamic characteristics such as lift and drag. Aerodynamic properties of an airfoil have a decisive impact on the performance of various engineering applications, including airplane wings and wind turbine blades. Therefore, it is essential to analyze the aerodynamic characteristics of airfoils. Various analytical tools such as experiments, computational fluid dynamics, and Xfoil are used to perform these analyses, but each tool has its limitation. In this study, airfoil parameterization, image recognition, and artificial intelligence are combined to overcome these limitations. Image and coordinate data are collected from the UIUC airfoil database. Airfoil parameterization is performed by recognizing images from image data to build a database for deep learning. Trained model can predict the aerodynamic characteristics not only of airfoil images but also of sketches. The mean absolute error of untrained data is 0.0091.

• Archives of design research
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• v.14 no.4
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• pp.5-14
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• 2001

Among Human Sensibility-oriented products a gap between the images that designers try to express through that product and users emotional evaluation becomes an issue. The data on the correlation between image words used for design evaluation and images used in the design process are especially significant. This study based on these correlations suggests a Fuzzy retrieval system supporting styling design with images and image words. In the system, the relational data are demonstrated by Fuzzy thesaurus as correlation coefficient from the degree of similarity among image words. And the degree of similarity is produced based on image evaluation. Image retrieval is conducted by the algorithm of Fuzzy thesaurus development, 1) among image words, 2) images to image words, 3) image words to images and 4) among images: 4 different modes are provided as retrieval modes. Also transfer between modes is carried by direct operating interface, therefore divergent thinking and convergent thinking is supported well. The system consists of operation for the gap and the measurement unit of emotional evaluation, and visualization units. Under unified interface environments are set in order for consistency of the operation.