• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.23 no.10
• /
• pp.134-142
• /
• 2009

In this paper, we proposed the right-angle stereo vision system to measure the object size using a human eyesight-like, and the system is reconstructed with conventional stereo vision system. In this proposed system, the size results of objects are measured very close to the real object size, and we got the ratios 93~103[%] for the real object sizes. Therefore, the suggested right-angle stereo vision system have a high possibilities to be applied to many industrial system parts and to be used for robot system, automatic system, and etc.

• Proceedings of the Korean Society of Medical Physics Conference
• /
• 2005.04a
• /
• pp.100-102
• /
• 2005

양성자 빔을 이용한 치료는 종양부위에 높은 선량을 균일하게 전달하고 정상세포에는 적은 선량을 전달할 수 있어 암치료 효과가 높으나 정확한 치료와 환자의 안전을 위해서는 양성자선량의 급락지점을 정확히 아는 것이 중요하다. 본 연구에서는 양성자와 물질과의 핵반응으로 직각방향으로 방출되는 즉발감마선을 측정하여 양성자선량 급락지점을 측정할 수 있는 검출시스템을 몬테칼로 전산코드로 전산모사하였으며, 70MeV 단일에너지 빔과 최대에너지가 70MeV인 SOBP 빔을 모의피폭체인 물팬텀에 조사하고 검출시스템을 통해 직각방향으로 방출되는 즉발감마선의 분포를 계산하였다. 모의피폭체 안에서의 양성자선량의 분포와 측정된 즉발감마선의 분포를 서로 비교하여 두 분포 사이의 상관관계를 찾고 이 상관관계를 이용하여 양성자선량 급락지점을 결정할 수 있음을 확인할 수 있었다.

• Investigative Magnetic Resonance Imaging
• /
• v.3 no.1
• /
• pp.6-12
• /
• 1999

Echo Planar Imaging (EPI) Spiral Scan 영상을 초고속 자기공명영상 기법으로서 전체 k-space의 데이터를 한번 scan에 다 받을 수 있기 때문에 데이터 측정시간을 100ms 이내로 단축시킬 수 있다. 이러한 초고속 영상 기법은 최근 활발히 연구되고 있는 뇌기능 영상과 관련하여 중요도가 더욱 커지고 있다. EPI는 직각좌표계에서 데이터를 받기 때문에 재구성은 비교적 쉬우나 eddy current를 많이 야기시키는 단점을 가지고 있다. 반면에 Spiral Scan 영상은 먼저 데이터를 원 또는 직각좌표계로 interpolation을 한 후 재구성하여야 하는 단점이 있으나, 상대적으로 eddy current가 작고, 방향과 무관하게 균일한 point spread function을 가지며, 혈류와 관련한 위상이 스스로 rephasing 되어 심장 영상 등에 유리한 장점이 있다.

• Journal of the Korean Society for Precision Engineering
• /
• v.33 no.4
• /
• pp.295-301
• /
• 2016

The out-of-squareness is one of the error sources that affect the positioning accuracy of machine tools and coordinate measuring machines. Laser interferometer is widely used to measure the position and angular errors, and can measure the squareness using an optical square. However, the squareness measurement using the laser interferometer is difficult, as compared to other errors due to complicated optics setup and Abbe's error occurrence. The effect of out-of-squareness mainly appears at the face-diagonal of the movable plane. The diagonal displacements are also affected by the position dependent geometric errors. In this study, the squareness estimation techniques via diagonal displacement measurement using the laser interferometer without an optical square were proposed. For accurate estimation and measurement time reduction, the errors selected from proposed discriminant were measured. Discrepancy between the proposed technique with the laser interferometer (with an optical square) result was $0.6{\mu}rad$.

• Journal of the Korean Society for Precision Engineering
• /
• v.10 no.3
• /
• pp.205-219
• /
• 1993

제품의 기하학적 칫수 공차는 생산제품의 품질관리에 매우 종요하며, 측정기기의 발달과 함께, 컴퓨터를 이용한 기하하적 공차 해석의 수요와 경향은 늘고 있는 추세이다. 본 논문에서는, ISO의 공차 정의에 기초한 공차들(진직도공차, 편평도공차, 진원도공차, 평행도공차, 직각도공차, 윤곽공차)을 해석할 수 있는 컴퓨터 모듈이 개발되었다. 특히 윤곽공차의 경우 측정프로브의 반경의 효과가 배제되는 알고리즘을 개발하였다. 개발된 컴퓨터 모듈을 실제적인 측정작업에 적용하였으며, 고종도와 고효율성을 보임을 입증하였다.

• Explosives and Blasting
• /
• v.21 no.1
• /
• pp.69-76
• /
• 2003

Test blasting has been performed with V-cut to investigate the characteristics. Blasting vibrations were measured at two directions, the proceed direction and side direction. Propagation characteristics were determined by regression analysis; square root scaled distance and cube root scaled distance with maximum charge per delay of the blast. Testing result, The cross point was 62m in the allowable vibration velocity of 3mm/sec and 46m In 5mm/sec. Also, vibration level with measuring point was highest and decayed fastest, adapting to cube root scaled distance, for the proceed direction on ground.

• Journal of Advanced Navigation Technology
• /
• v.26 no.5
• /
• pp.344-349
• /
• 2022

A compact LPDA antenna consisting of right triangle-shaped dipole elements appended with strips is proposed for UWB applications. First, right triangle-shaped dipole elements are used instead of conventional strip dipole elements to reduce the width of the LPDA antenna. Second, the spacing between the LPDA elements is decreased to reduce the length of the LPDA antenna. Finally, strips are appended at the ends of the right triangle-shaped dipole elements in order to further reduce the width of the antenna. A prototype of the proposed antenna with 16 elements and gain > 4 dBi is fabricated on an FR4 substrate with dimensions of 44 mm×30 mm. Measured frequency band of the fabricated antenna is 2.99-14.76 GHz for a VSWR < 2, which ensures UWB operation, and measured gain range is 4.0-5.5 dBi with a front-to-back ratio larger than 10 dB. The length and width of the proposed compact LPDA antenna are reduced by 40.9% and 20.6%, respectively, compared to the conventional LPDA.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.7 no.1
• /
• pp.131-139
• /
• 1987

In this study, characteristics of multi-photos and optimal photographing method are suggested by analyzing the normal case and convergent case with multiple method. The optimal photographing method is applied to deformation measurement of a model miniature structure under loading. Comparing with conventional measurement method in accuracy, efficiency and proprities of application of this method are suggested. As a result, the optimal photographing condition is ideal at $90^{\circ}$ convergent multiple case, whose measurement values approach to that of precision level within $5{\sim}9{\mu}m$ and bring more than about 55% improvement of accuracy comparing with normal case at the number of photos respectively. Therefore application of this method in deformation measurement as well as precision analysis of structures is desired in precision and economical aspect.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2000.04a
• /
• pp.75-81
• /
• 2000

This study for the roundness and perpendicularity of machining center is classified into two ways. One is the way that progresses the roundness amending the parameter of machining center based on the measured value after the measurement of the roundness of machaning center by means of a existing measuring device, another is the way that measures the roundness by remodeling the existing measuring device. the former is studied by pack hei jae team in Seoul university, the later is studied by TSUTSUMI. Especially TSUTSUMI measures the roundness according to circular compensation after the insertion of developed measuring device using a rotary encoder to the spindle of machining tool. we study how regulation velocity occuring with circular motion of machining center table influences the roundness after measuring the roundness using Circular Test method by a 2 dimention probe and a standard discus in this experiment.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.13 no.12
• /
• pp.1184-1195
• /
• 2001

Analysis of fluid flow in rectangular ducts has been conducted since it has a wide application. The purpose is to provide experimental data for the comparison with computational results. Velocity distributions inside a rectangular duct with $90^{\circ}$ mitered elbow are measured by 5W laser doppler velocity meter for Reynolds numbers of 4,049, 8,104, and 12,186. Flow rates obtained by the integration of measured velocity profile at three cross-sections, which are inlet, middle section after the elbow, and outlet, have errors less than 0.9% among them. Turbulent fluctuation components in two directions are found to have almost similar magnitude each other at a certain location due to the isotropic characteristic of turbulence.