• Korean Journal of Applied Biomechanics
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• v.12 no.2
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• pp.345-359
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• 2002

The purpose of the study was to provide the fundamental data to instruct athletes through the analysis athletes' movement in javelin. Three athletes in the level of national representative were participated in this study. The study analyzed kinematic variables(lead foot and releasing javelin) through 3-D analysis and obtained the following results. 1. During withdrawal, it is important to maintain of running horizontal velocity. 2. It was showed that throng average height was $84{\pm}3.3%$ and javelin adequative degree, Among the athletes, $S_2$ who had the best record was released the javelin with the fast velocity, but throw the javelin with the less releasing velocity. 3. $S_2$ released after lead foot were completely landed and therefore it is no problem in a kinematic aspect. However, $S_1$ angle was too small. it caused increase of release velocity to be prevented. 4. $S_2$ showing the best result indicated shorter in duration time. Generally, the shorter duration time in release phase showed the longer release distance. Especially $S_1$ and $S_3$ showing the worse result indicated the longer duration time in preparatory phase, causing the breakup of force. Therefore to improve the record, it should be decreased the duration time in preparatory phase. 5. Compared with $S_1$ and $S_3$, $S_2$ showing the best record indicated the higher velocity in center of mass, trunk, upper arm, lower arm and hand That is the higher velocity of upper arm at release leaded the better velocity transfer from upper arm to following lower arm and hand, these action should be considered to be helpful of better record. According to the above conclusion, when the athletic leaders cauch athletes, they should focus on maintaining knee angle, upper body and hip angle in a previous stage of release and throwing angle, throwing height, throwing velocity in a release stage.

• The korean journal of orthodontics
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• v.33 no.2 s.97
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• pp.73-84
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• 2003

This study was performed to find out how much projection errors in the cephalometric measurements were made by vertical head rotation in taking posteroanterior cephalograms. 25 adults without any apparent facial asymmetry or severe sagittal skeletal discrepancy were selected and the posteroanterior cephalograms were taken with the head rotated $5^{\circ},\;10^{\circ}$ superior and inferior each to the reference $position(0^{\circ})$. The 7 height, 5 width and 6 angular measurements were taken at each 5 positions. Through the statistical analysis of all measurements taken at each rotated position, folowing results were obtained.1. The projection errors of height measurements were remarkably target than those of width or angular measure nents. f. Among the height measurements, the farther to the rotation axis the measurements were, the larger the projection errors were. 3. Among the width measurements, mandibular width and mandibular width of mandibular first molars showed significant differences between the values taken at each rotated position, while nasal width, maxillary width and intermolar width of maxillary first molars did not. 4. Among the angular measurements, the angle between horizontal reference line and the line that is connected to crista galli and antegonion or maxillare showed significant differences between the values taken at each rotated Position. The above results suggest that it is needed to the effort to keep constant head position for taking the useful posteroanterior cephalogra, because projection errors are caused by vertical head rotation.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2010.07a
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• pp.438-439
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• 2010

산란선을 흡수하여 보다 선명한 x선 영상을 얻기 위하여 산란방지 그리드를 사용하여 투사영상을 얻는데, 이때 그리드로 인한 왜곡이 발생한다. 본 논문에서는 회전된 그리드를 사용하여 투사영상을 얻어서 그리드 왜곡을 제거하는 방법에서, 보다 효율적인 그리드 왜곡 제거를 위한 최적의 그리드 각도를 얻기 위한 min-max 최적화 방법을 제시하였고, 몇 가지 예를 통하여 최적의 그리드 각도를 구하였으며, 실제 x선 영상에 적용하여 그 성능을 비교해 보았다.

• Korean Journal of Applied Biomechanics
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• v.12 no.2
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• pp.159-177
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• 2002

The purpose of this study was to investigate the relations between the segments of the body, the three dimensional anatomical angle and the angular velocity of the air born phase and understand the control mechanism of the high-bar movement, the somersault, the double somersault, the double somersault with full twist. For this study seven well trained university gymnastic volunteered, Zatsiorky and Seluyanov(1983, 1985)'s sixteen segment system anatomical model was used for this study. For the movement analysis three dimensional cinematographical method(Arial Performance Analysis System : APAS) was used and for the calculation of the kinematic variables a self developed program was used with the LabVIEW 5.1 graphical profromming(Johnson, 1999) program. By using Eular's equations the three dimensional anatomical Cardan angles of the joint and angular velocity were defined. As a result of this study 1. As the rotation of the body increased in the air born phase the projection angle of the CM of the total increased, this resulted the increased of the max hight of the CM. 2. In three dimensional angular velocity the Z axis(vertical direction) projection angular velocity increased as the rotation of the body increased in the airborn phase, but the Y axis and the X axis projection angular velocity did not show significant differences. 3. As the rotation of the body increased in the air born phase the angular movement of the shoulder and the hip showed significant change. These movement act as the starter in the preparation phase. 4. The somersault angle, the twist angle, the tilt angle of the upper body related to the global reference frame in the releas phase the average somersault angle of the three types of high-bar movement was $57.7^{\circ}$, $38.8^{\circ}$, $39.7^{\circ}$, the average tilt angle was $-1.5^{\circ}$, $-5.4^{\circ}$, $-8.4^{\circ}$, the average twist angle was $13.4^{\circ}$, $10.6^{\circ}$, $23.3^{\circ}$. This result showed that the somersault with full twist had the largest movement.

• Proceedings of the Korea Contents Association Conference
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• 2012.05a
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• pp.405-406
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• 2012

이 연구는 여자 창던지기 선수들의 투사요인, 창 각의 특성과 기록과의 관계를 통해서 기록에 미치는 영향을 분석한 것이다. 투사요인 중 투사높이와 투사속도가 기록과 정적 관계를 보이면서 릴리즈순간 투사높이가 높고, 투사속도가 클수록 기록이 좋은 것으로 나타났다. 특히 창 각과 관련된 자세각과 공격각의 경우 기록과 낮은 관계를 보인 반면에 요 각은 기록과 정적 관계를 보여 릴리즈 순간 0보다 큰 각도에서 릴리즈가 이루어져야하는 것으로 나타났다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.8
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• pp.3758-3765
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• 2011

The operators' visibility of underwater construction equipments plays a key role for safe and efficient construction. The visibility can be limited within 30cm in the West Sea of South Korea where water is considerably turbid. This paper investigates the appropriate location and projection angle of light to be used for construction equipments using model tests. It was discovered that visibility was obtained when the light was located near the target objects with a projection angle of $45^{\circ}$.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.382-384
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• 2019

In this study, we analyzed the angle of shooting based on the footage of shooting training of basketball student athletes taken by the basketball team leaders. In the shooting video, the shot height of the player and the trajectory of the ball were drawn through a solid line, and the player was shown to guide the player to adjust the angle of projection to a situation where the success rate was higher. Through this study, the video shows that efficient guidance can be made available to basketball players.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1995.04a
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• pp.656-666
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• 1995

본 논문에서는 물체위로 투사된 line stripe으로부터 물체의 표면 정보를 추출하기 위해 2-D Grip paper를 이용해 캘리브레이션하는 방법이 제안되었다. 카메라의 이미지평면과 카메라의 가시범위에 있는 3차원 실세계간의 Projective Tranformation과정에서는 목표물과 이미지 평면사이의 거리나 각도 등이 정보를 실제로 측정해서 알고 있어야만 카메라와 실세계간의 캘리브레이션을 수행할 수 있다. 그러나 이미 크기나 거리를 알고 있는 Grid paper를 이용하면 카메라의 파라미터들에 대한 추정이나 카메라와 실세계간의 측정을 하지 않고서도 목표물위로 투사된 line stripe에 대한 정보를 얻을 수 있고 이를 이용해 물체의 표면에 대한 정보를 얻을 수 있다. 이미 지평면에 투영된 격자패턴에서 구한 교차점들의 위치를 이용해 실제 위치를 찾아낸다. 실제로 레이져스캐너를 이용해 물체위로 line stripe을 투사한 후, 위에서 제시한 방법을 통해 3차원 정보를 구하는 실험결과는 양호하였다.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.207-208
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• 2007

In this paper, the tilted image sequence, which is obtained the transmission electron microscopy (TEM) for a 3D reconstruction, is aligned based on the fiducial marker method. A direct correlation method is also conducted between adjacent tilted images for the performance comparison. Using real TEM tilted images, we can successfully perform the alignment.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2008.10a
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• pp.324-328
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• 2008

지상 LiDAR(Light Detection And Ranging)는 정밀하고 빠르게 물체의 3차원 형상을 측량할 수 있는 시스템이다. 기본적으로 종전의 레이저 측량기의 기능을 갖고 있으며, 초당 최대 $5,000{\sim}50,000$ point의 레이저를 대상체 표면에 발사하여 대상체면에 투사한 레이저의 간섭이나 반사를 이용하여 대상체면상의 point could의 공간정보를 취득하는 관측방식의 3차원 정밀 측량으로서 대상체의 표면으로부터 상대적인 3차원(X, Y, Z) 지형공간좌표를 각각의 Point 데이터로 기록한다. 이러한 측정방법은 레이저가 반사되어 돌아오는 시간을 계산하여 거리를 결정하고 ${\theta}_h$(수평각)과 ${\theta}_v$(수직각) 각도만큼 수평, 수직으로 회전하여 측정한 점의 위치를 결정하므로 데이터 취득 각도에 따른 오차가 발생하게 된다. 본 연구 에서는 지상LiDAR 데이터 취득각도에 따른 오차 시뮬레이션 실시하여 실제 실험과의 비교 및 입사각에 따른 정확도 분석을 실시하였다.