• Proceedings of the Korean Information Science Society Conference
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• 2010.06b
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• pp.167-172
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• 2010

최근 디스플레이가 대형화되고 고해상도화 되면서 단순한 정보를 보여주는 단방향 디스플레이에서 사용자가 디스플레이와 상호작용 할 수 있는 환경을 제공해주는 양방향 인터랙티브 디스플레이로 진화하고 있다. 본 논문에서는 이러한 문제점을 해결하기 위하여 대형 디스플레이 환경에서 비주얼 코드를 이용하여 사용자가 편리하고 효과적으로 인터랙션 할 수 있는 방법에 초점을 맞추었다. 모바일 장치에 출력된 인터랙션 코드가 대형디스플레이 상단의 카메라에 입력되어 시스템은 마커의 좌표 값(x, y, z)을 얻게 된다. 모바일 장치의 기울임 정도를 마커의 좌표 값을 이용하여 판단하고 좌우 회전인 Pitch 동작과 상하회전인 Yaw 동작을 디스플레이 상의 커서에 맵핑하여 모바일 장치를 기울임으로서 커서를 조작할 수 있게 된다.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.207-208
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• 2015

팬(fan), 펌프(pump), 블로어(blower), 전기 자동차(electric/hybrid vehicle), 전동차와 같은 다양한 분야에서 3상 전동기의 고속 운전에 대한 요구가 증대되고 있다. 일반적으로 3상 전동기가 정격 속도 이상의 고속에서 운전하기 위해서는 회전자 자속(rotor flux)의 크기를 운전 상황에 따라 감소시키는 약자속(flux weakening) 제어가 필수적이다. 유도 전동기의 회전자 자속 기준 벡터 제어 시의 약자속 운전은 자속 성분 전류의 크기를 제어하여 유도 전동기의 고속 운전을 가능하게 하는데, 이러한 전류 제어 기반의 약자속 제어는 그 구조가 복잡하고, 제어기 이득 선정에 따른 동특성(dynamic)이 영향울 받는 문제점을 가지고 있다. 본 논문에서는 이러한 단점을 개선하기 위한 순시적 약자속 제어 방법을 제안하고 3.7kW 유도 전동기를 이용한 실험을 통하여 제안된 방식의 성능을 검증한다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.11
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• pp.1092-1100
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• 2011

A C-band ground-based rotational SAR system is presented in this paper. The rotaional SAR system is a test-bed for future rotational SAR systems which can be deployed in space and on a tower. The test-bed system is designed for imaging the electromagnetic scattering from earth surfaces and buried targets. This paper also presents the examination results of the generated SAR images. This rotational SAR system is basically consisted of the network-analyzer based HPS(Hongik Polarimetric Scatterometer) and a horizontally rotating arm. Several SAR images were obtained using the rotational SAR system for various target areas. To verify this system, we simulated the SAR images for the rotational SAR using the FDTD algorithm and compared between the measured and simulated SAR images. The rotational SAR system is operated at the center frequency of 5 GHz and various frequency bandwidth within 0.5~2 GHz to change the resolution of SAR images.

• Clinics in Shoulder and Elbow
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• v.13 no.2
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• pp.280-285
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• 2010

Purpose: Coracoid impingement syndrome refers to subscapularis impingement between the coracoid process and lesser tuberosity of the humerus, and pain may occur when the arm is positioned in forward flexion, internal rotation and adduction. This position is common for archers. Material and methods: A female archer with coracoid impingement syndrome that was uncontrolled by conservative therapy underwent arthroscopic subcoracoid decompression. At the 20th postoperative month of follow up, she complained of painful rotator interval widening and so she underwent arthroscopic rotator interval plication. Results: At the postoperative 6th month of follow up after the second operation, she showed no pain and good functional results, and she returned to competing as an archer. Conclusion: We have reported here on a case of successful treatment of painful rotator widening after subcoracoid decompression in an elite archer.

• Proceedings of the Korea Multimedia Society Conference
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• 2002.05d
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• pp.721-725
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• 2002

가상현실 기술에는 공간상에 가상현실을 구현하기 위한 파노라마 기술과 사물의 가상현실을 구현하기 위한 오브젝트 기술 두 부분으로 나누어진다. 현재까지의 기술 중 오브젝트 가상현실에 대하여서는 관찰자가 오브젝트론 상, 하, 좌, 우로 회전, 이동시키면서 확대, 축소 가능한 상태로 볼 수 있는 입체적인 접근 방법을 제공하지만, 파노라마 가상현실의 표현에 있어서는 제작 방식의 제한된 상황으로 천장과 바닥의 표현이 왜곡되거나 표현되지 못하는 단점을 보이고 있는 실정이다. 따라서 본 연구에서는 파노라마의 기본적 개념과 파노라마 가상현실 제작과정을 통하여 상하 표현의 제한되는 단점을 파악하고, 상하의 표현을 근본적으로 가능하게 하는 정육면체 타입의 새로운 데이터 형식을 제안하여 파노라마 가상현실 공간을 구성하도록 한다.

• Journal of the Korean earth science society
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• v.26 no.7
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• pp.725-731
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• 2005

The distribution and kinematic information of the planetary nebula (PN) may provide a hint about the Galactic dynamics and evolutionary history. An analysis of the Galactic planetary nebular distribution and kinematics (distance, direction, velocity) is underwent, using the 502 PNs observational data given in the ‘THE STRASBOURG-ESO CATALOGUE OF GALACTIC PLANETARY NEBULAE.’ The representative average radial velocities, $(V_r)s$ is derived in six different directions of galactic latitudes, $l = 0^{\circ},\;90{\circ},\;180{\circ},\;270{\circ},$ plus apex and antapex $(56{\circ},\;236{\circ})$, respectively. The PNe near the apex approaches to the Sun with radial velocities, which values are $(V_r) = 69.0 km/s;$ whereas, those near the antapex recedes with $(V_r) = 64.1 km/s$, respectively. No particular trends are found along the z direction, although more PNs are found below the Galactic plane. This implies that the 3rd generation objects, PNs, move slowly on the galactic plane compared to the 4th generation stars like the Sun, indicative of possible interaction.

• Proceedings of the KIEE Conference
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• 1982.07a
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• pp.42-47
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• 1982

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.9
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• pp.835-846
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• 2007

This paper deals with the flexural free vibrations of circular strip foundation with the variable breadth on Pasternak soil. The breadth of strip varies with the linear functional fashion, which is symmetric about the mid-arc. Differential equations governing flexural free vibrations of such strip foundation are derived, in which the elastic soil with the shear layer, i.e. Pasternak soil, is considered. Effects of the rotatory and shear deformation are included in the governing equations. Differential equations are numerically solved to calculate the natural frequencies and mode shapes. In the numerical examples, the hinged-hinged, hinged-clamped and clamped-clamped end constraints are considered. Four lowest frequency parameters accompanied with their corresponding mode shapes are reported and parametric studies between frequency parameters and various system parameters are investigated.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.8
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• pp.11-23
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• 2000

Head-eye calibration is a process for estimating the unknown orientation and position of a camera with respect to a mobile platform, such as a robot wrist. We present a new head-eye calibration technique which can be applied for platforms with rather limited motion capability In particular, the proposed calibration technique can be applied to find the relative orientation of a camera mounted on a linear translation platform which does not have rotation capability. The algorithm find the rotation using a calibration data obtained from pure Translation of a camera along two different axes We have derived a calibration algorithm exploiting the rectification technique in such a way that the rectified images should satisfy the epipolar constraint. We present the calibration procedure for both the rotation and the translation components of a camera relative to the platform coordinates. The efficacy of the algorithm is demonstrated through simulations and real experiments.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.14 no.3
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• pp.371-379
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• 2001

This paper deals with the free vibrations of horizontally curved members resting on elastic foundations with continuity effect. Taking into account the effects of rotatory inertia and shear deformation, differential equations governing the free vibrations of such beams are derived, in which the Pasternak foundation model is considered as the elastic foundation with continuity effect. The differential equations are solved numerically to calculate natural frequencies and mode shapes. The experiments were performed in which the natural frequencies of such curved beams in laboratorial scale were measured and these results agree quite well with the present numerical studies. In numerical examples, the circular, parabolic, sinusoidal and elliptic curved members with the hinged-hinged, hinged-clamped and clamped end constraints are considered. The parametric studies are conducted and the lowest four frequency parameters are reported in tables and figures as the non-dimensional forms. Also the typical mode shapes are presented.