• Proceedings of the Optical Society of Korea Conference
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• 2000.02a
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• pp.230-231
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• 2000

최근 자동차, 항공기 등 연소과정을 수반하는 산업이 발전함에 따라 연소환경에 대한 관심이 높아지고 있다. 그런데 연소환경을 접촉식 방법으로 측정하게 되면, 측정기기가 연소환경에 영향을 주기 때문에 정확한 측정을 하기는 어렵다. 그래서 레이저를 이용한 비접촉식방법이 활용되고 있으며,$^{(1)}$ 그 중에서 LIGS(laser induced grating spectrosopy)나 DFWM(degenerate four wave mixing)$^{(1)}$ 은 신호대 잡음비가 높기 때문에 미세량으로 존재하는 분자를 검출하는데 유용할 뿐만 아니라 2차원 영상수집도 가능하다. 또한 LIGS의 시분해 신호를 분석하면 연소장내의 온도와 입자의 밀도 등을 산출할 수 있다. 본 실험에서는 대기압에서 불완전 연소장의 soot에 대한 신호를 수집, 분석하여 화염 위치에 따른 온도 변화와 soot의 농도 등을 정량적으로 조사했다.$^{(2)}$ (중략)

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1992.04a
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• pp.9-12
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• 1992

지금까지 공작기계의 성능은 주로 기하학적 운동정도, 위치결정정도, 공작정도등의 시험 및 검사에의해 평가되어왔다. 그러나, 공작기계의 수치제어 System으로서의 평가는 충분히 행히지고있지 않았다. 원호절삭 정도시험으로서 Direct Test법은 공작물을 직접절삭하기 때문에공구나, 공작물의 영향을 받아서 공작기계의 운동정도만을 검사하는 것은 곤란하다. 그래서 직접 절삭하지않고 원호절삭 원동정도를 평가할 수 있는 방법으로서 Circular test법과 Double Ball Bar법이 개발 되어 사용되고 있다. 본 연구에서는 상술한 2가지 방법의 대체 방법으로 간단하고 값싸게 제작할 수 있는 새로운 원호절삭 정도측정장치와 측정 system을 개발하여 이 측정기로측정한 원호형상과 Machining Center의 운동오차 요인과의 정량적으로 고찰하였다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.10a
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• pp.69-70
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• 2006

• The korean journal of orthodontics
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• v.31 no.1 s.84
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• pp.15-24
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• 2001

In order to achieve a desirable tooth movement, it is of great importance to control the M/F ratio and to know the location of the center of resistance. The purpose of this study was to locate the center of resistance and the axis of rotation, and to estimate the stress distribution in the periodontal ligament with experimental model. After preparing a model of an upper canine with a simulated periodontal ligament and alveolar bone, the force and moment were applied. The tooth movement was traced using measuring device with LVDTs(Linear variable differential transformers) that can measure three dimensional tooth movement in real time. The results were as follows. 1. The location of center of resistance by transverse force was $29\%$ of root length measured from alveolar crest to apex regardless of force magnitude. The position of the center of resistance is more coronal than that of two-dimensional model($42\%$). 2. The center of resistance and the axis of rotation coincide when couple moment was applied. 3. As the magnitude of moment increases, tooth tends to extrude irrespective of the direction of the moment. 4. The relationship between location of force and axis of rotation (a x b = $49.6\;mm^2$) was obtained. A tooth movement can be predicted through this formula. 5. The centers of rotation by transverse force were plotted linearly.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.31 no.2
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• pp.159-164
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• 2013

It is well known that a single moving camera video is capable of extracting the 3-dimensional position of an object. With this in mind, current research performed image-based monitoring to establish a floating structure model using a camcorder system. Following this, the present study extracted frame images from digital camcorder video clips and matched the interest points to obtain relative 3D coordinates for both regular and irregular wave conditions. Then, the researchers evaluated the transformation accuracy of the modified SURF-based matching and image-based displacement estimation of the floating structure model in regular wave condition. For the regular wave condition, the wave generator's setting value was 3.0 sec and the cycle of the image-based displacement result was 2.993 sec. Taking into account mechanical error, these values can be considered as very similar. In terms of visual inspection, the researchers observed the shape of a regular wave in the 3-dimensional and 1-dimensional figures through the projection on X Y Z axis. In conclusion, it was possible to calculate the displacement of a floating structure module in near real-time using an average digital camcorder with 30fps video.

• Spatial Information Research
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• v.15 no.2
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• pp.169-180
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• 2007

Applicability of Land-based MMS(Mobile Mapping System) having been increased gradually as digitalization of administrative operation and construction of integrated systems of the government and provincial government are growing up. As these requirements, the case can be occurred that the facilities should be surveyed rapidly in the specific area. At this case, the real time field processing method is more necessary than the post processing method and data processing speed should be an essential element as important as accuracy. In this study, the two space intersection methods used in photogrammetry were programmed and compared with each other to select more proper method for the three dimensional positioning in the field processing. Especially, at the analytic space intersection, the traditional close range terrestrial photogrammetry was modified and applied to that to adapt to MMS's characteristics that camera position and attitude are changed according to the vehicle movement. As a result, the difference of the accuracy between two methods is not significant but at the calculation time, the analytic space intersection is faster three times than the space intersection using collinearity condition.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.375-375
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• 2010

텅스텐 (110)면에 알루미늄 원자를 흡착시켜 저에너지 전자회절(LEED)과 이온산란분광법(ISS)을 이용하여 흡착구조를 연구하였다. 깨끗한 텅스텐 (110)면 표면에 알루미늄을 0.8ML 흡착시킨 후 1100K 온도로 열처리를 하였을 때 2-도메인의 p($2{\times}1$) LEED 이미지가 관측되었다. Al/W(110)-p($2{\times}1$)계면에서 알루미늄 원자가 텅스텐 표면원자와의 결합거리와 방향 등 3차원적 흡착위치를 알아보기 위해 이온산란분광법을 이용하여 측정하였다. 그 결과 알루미늄 원자는 텅스텐의 두 원자 사이(bridge-site)의 가운데에 위치하였으며, 텅스텐의 첫 번째 원자 층으로부터의 높이는 $2.18{\pm}0.01{\AA}$이다. 알루미늄 원자와 가장 가까운 텅스텐 원자까지의 거리는 $2.57{\pm}0.01{\AA}$이다.

• Geophysics and Geophysical Exploration
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• v.12 no.1
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• pp.69-76
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• 2009

We report an implementation of the Ground Penetrating Radar (GPR) survey at a site that corresponds to a ruined castle. The objective of the survey was to characterise buried archaeological structures such as walls and tiles in Van Khan Tooril's Ruin, Mongolia, by 2D and 3D GPR techniques. GPR datasets were acquired in an area 10mby 9 m, with 10 cm line spacing. Two datasets were collected, using GPR with 500MHz and 800MHz frequency antennas. In this paper, we report the use of instantaneous parameters to detect archaeological targets such as tile, brick, and masonry by polarimetric GPR. Radar polarimetry is an advanced technology for extraction of target scattering characteristics. It gives us much more information about the size, shape, orientation, and surface condition of radar targets. We focused our interpretation on the strongest reflections. The image is enhanced by the use of instantaneous parameters. Judging by the shape and the width of the reflections, it is clear that moderate to high intensity response in instantaneous amplitude corresponds to brick and tiles. The instantaneous phase map gave information about the location of the targets, which appeared as discontinuities in the signal. In order to increase our ability to interpret these archaeological targets, we compared the GPR datasets acquired in two orthogonal survey directions. A good correlation is observed for the alignments of reflections when we compare the two datasets. However, more reflections appear in the north-south survey direction than in the west-east direction. This is due to the electric field orientation, which is in the horizontal plane for north-south survey directions and the horizontally polarised component of the backscattered high energy is recorded.

• Journal of Advanced Navigation Technology
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• v.27 no.2
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• pp.190-196
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• 2023

Recently, following the development of LIDAR technology which can detect distance from the object, the interest for LIDAR based 3D object detection network is getting higher. Previous networks generate inaccurate localization results due to spatial information loss during voxelization and downsampling. In this study, we propose an attention-based convergence method and a camera-LIDAR convergence system to acquire high-level features and high positional accuracy. First, by introducing the attention method into the Voxel-RCNN structure, which is a grid-based 3D object detection network, the multi-scale sparse 3D convolution feature is effectively fused to improve the performance of 3D object detection. Additionally, we propose the late-fusion mechanism for fusing outcomes in 3D object detection network and 2D object detection network to delete false positive. Comparative experiments with existing algorithms are performed using the KITTI data set, which is widely used in the field of autonomous driving. The proposed method showed performance improvement in both 2D object detection on BEV and 3D object detection. In particular, the precision was improved by about 0.54% for the car moderate class compared to Voxel-RCNN.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.316-316
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• 2011

본 연구에서는 고수호안의 수리학적 안정성을 검토하는 것이다. 수리학적 안정성 검토를 위해 수리실험과 원형실험을 실시하였으며 이에 따른 수치모형도 병행 하였다. 수리 실험에 실험수로 제원은 총 길이가 14 m(정류부 3 m, 안정화 구간 3 m, 세굴측정구간 6 m, 하류부 2 m)로서 폭은 1.2 m이고, 높이는 0.6 m이다. 하류부에는 수위 조절을 위한 수문이 설치되어져 있는 곳에서 다양한 수리학적 조건 등을 실험을 실시하였다. 유실율 산정은 사면측정기를 활용하여 2 cm 간격으로 통수전 후의 세굴심을 측정하여 산정하였다. 유속분포에 관한 측정은 통수 시 3차원 VECTRINO MICRO ADV(N-7781)를 이용하여 측정하였다. 원형실험은 안동에 위치한 하천 종합실험센터에서 실시하였으며 사용한 A1 수로는 총연장 594.0m, 상류단과 하류단의 표고차는 4.50m이며, 단단면 하도로 구성되어져 있고, 실험 수로 연장은 434.0m이며, 상류단과 하류단의 표고차는 3.70m이며, 흐름안정구간, 호안공 검 인증 구간, 조도계수 연구구간으로 구성되어져 있는 곳에서 다양한 유량조건에 따른 실험을 실시하였다. 유실율 산정은 세굴봉을 활용하여 5 cm 간격으로 통수전 후의 세굴심을 측정하여 산정하였다. 유속분포에 관한 측정은 통수 시 흐름을 감안하여 프라이스컵을 이용하여 측정하였다. 수리학적 안정성은 각 실험에 측정한 유속분포와 유속을 이용한 소류력 산정 그리고 유실율 산정 등을 통해 수리학적 안정성을 확보하기 위한 분석하였다.