• Journal of the Korean Society of Visualization
• /
• v.11 no.1
• /
• pp.22-27
• /
• 2013

An investigation into the influence of ultrasonic standing wave on the structural behavior of propane/air premixed flame has been made to get a clue to the combustion reaction acceleration and combustion instability. Visualization technique utilizing the Schlieren photography was employed for the observation of structural variation of the flame reaction zone. Evolutionary characteristics of the flame front were caught by the high-speed Schlieren image, through which local flame velocity of the moving front were analyzed in detail.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
• /
• 2010.04a
• /
• pp.249-250
• /
• 2010

The study aims to propose a method that shall rapidly acquire 3D spatial information of the frequently changing city areas by using the low altitude aerial images taken by the UAV. The artificial 3D model of the artificial structures was constructed using the aerial image data photographed at the test area, calibration data of the non-metric camera and the results of the ground control point survey. Also, the digital surface model was created for areas that were changed due to a number of civil works. Through the above studies, the possibilities of constructing a 3D virtual city model, renewal of 3D GIS database, abstraction of changed information in geographic features and on-demand updating of the digital map were suggested.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.3 no.6
• /
• pp.250-261
• /
• 1995

In this study, a rapid compression and expansion machine(RCEM) equipped with a swirl generator was designed and developed, in order to clarify normal and abnormal combustion(knocking phenomena). This RCEM is intended to simulate combustion process in actual automotive S.I.engines, having a high reproducibility in the compression stroke. Flame propagation and autoignition processes associated with normal and abnormal combustion were captured by the high speed schlieren photography. And swirl intensity. equivalence ratio and ignition position were varied to investigate the effect of turbulence, concentration in the unburnt gas region and flame propagation length. The knock intensity, knock mass fraction and knock mass fraction after autoignition were calculated by use of history of measured cylinder pressure.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2011.04a
• /
• pp.39-44
• /
• 2011

This study constructed the spray distribution by the Tomography method at high pressure condition. The constructed spray distribution was compared with the images by Indirect Photography method so that the spray size was confirmed and took the boundary of the distribution. It was confirmed that the Tomography applies to construct the distribution at high pressure.

• Information Display
• /
• v.3 no.2
• /
• pp.39-48
• /
• 2002

본 논문에서는 무안경식 3차원 디스플레이 기술 중 최근 주목 받고 있는 집적 영상 기술에 관하여 논의한다. 초기 집적 영상 기술의 문제점들과 이를 해결하기 위해 제안된 주요 방법들을 소개하고, 최근 해외 및 국내의 관련 연구 동향에 관하여 기술한다.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.4 no.1
• /
• pp.137-144
• /
• 1984

In comparison to normal photography, oblique photography has large coverage area and is easily applicable to objects which are difficult to approach. But it has its deficiency of having to go through complex procedures of rectification. Oblique photographs are first analytically rectified, in this paper, then the coordinates of facilities are analysed.

• 한국연소학회:학술대회논문집
• /
• 2002.06a
• /
• pp.61-67
• /
• 2002

Characteristics of lifted flames in axisymmetric laminar coflow jets have been investigated experimentally. Approximate equations for velocity and concentration with virtual origins have been proposed to analyze the behavior of flames in coflow jets. Measuring Rayleigh intensity to investigate the concentration field. proposed approximate equations were confirmed. By using the results of OH PLIF, direct photography and Rayleigh scattering measurement, it is shown that the locations of maximum intensity in direct photography coincide with the tribrachial points in axisymmetric jets and the tribrachial points travel on the stoichiometric contour. For coflow jets, the experimental results of liftoff height have been successfully correlated with nozzle exit velocity using predicted behavior from proposed approximated equations. These results substantiate the stabilization mechanism in coflow jet is based on the balance between flame propagation speed and axial flow velocity, same as for the free jets.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2003.07a
• /
• pp.1034-1037
• /
• 2003

In this work, Integral photography with variable focusing lens arrays is proposed. We fabricate two-dimensional liquid crystal lens arrays using cohesion of UV curable polymer and lithography. Applied voltage to the cell alters the effective refractive index of the liquid crystal layer and results in a change of the focal length. By adjusting the focal length, synchronized elemental image array for real or virtual mode is integrated in front of or behind the lens array.

• Proceedings of the KSME Conference
• /
• 2004.04a
• /
• pp.420-425
• /
• 2004

Lee and Kang measured side-necking deformation near a crack-tip for CT specimen using Stereoscopic Digital Speckle Photography and Digital Image Correlation. In this work the same technique was applied to SENB specimen. We happened to find that the deformation shape of the side-necking is similar to the one of plastic region estimated by McClictock using slip line theory. Based on volume constancy of plastic deformation as well as this finding, it is expected that a linear relationship holds between the volume of plastic deformation region and the one of side-necking upon the lateral surface of a specimen. To prove the idea, a preliminary study has been performed using 3-D finite element method on a model with modified boundary layer formulation. As the result, it is shown that the idea works well with acceptable error.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.59 no.2
• /
• pp.188-193
• /
• 2014

Seed viability testing provides valuable information for assessing seed lot germinability. However, most testing methods require destruction of seed prior to test. Because the dissected seeds for viability test cannot be used further evaluation, the nondestructively X-ray photography technique that can be applied for the evaluation of seed quality has been developed. In order to know the validity and accuracy of X-ray photography technique in seed evaluation test that conducted to remove the abnormal seed from a seed lot, we have compared the results from tetrazolium viability test, germination test and X-ray contrast method in cotton. Metallic salts treatment increased the efficiency of X-ray photographic method by enhancing the penetration of X-ray in abnormal or damaged seeds rather than normal seeds that have strong and well-organized tissues in seed. Cotton seeds presoaked for 16 hr in distilled water followed by soaking into metallic salt solution (5% NaI in water) for 60 min were easily classified seeds into dead seed and viable seed based on the radiography images obtained by X-ray radiation. We concluded that soft X-ray photography was reliable to find out the various defective characters due to heat and mechanical damage of seeds.