• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.4
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• pp.371-378
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• 1992

In this paper we report the fabrication of a planar optical wavehuide lens on a Y-cut LiNbO3 substrate by Ti_indiffusion and Ti-indiffused proton-exchange(TIPE). LiNbo3 planar waveguides are fabricated and refractive indices of the waveguides are fabricated and refractive indices of the waveguides are measured. Based on the measured indices, palanr waveguide lenses are designed and fabricated. The measured focal point and spot size of the fabricated lens are in good agreement with those of the designed lens.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.2
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• pp.127-136
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• 2007

In this paper, the equations of the scaled boundary finite element method are derived for non-homogeneous half plane and analyzed numerically In the scaled boundary finite element method, partial differential equations are weaken in the circumferential direction by approximation scheme such as the finite element method, and the radial direction of equations remain in analytical form. The scaled boundary equations of non-homogeneous half plane, its elastic modulus varies as power function, are newly derived by the virtual work theory. It is shown that the governing equation of this problem is the Euler-Cauchy equation, therefore, the logarithm mode used in the half plane problem is not valid in this problem. Two numerical examples are analysed for the verification and the feasibility.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05a
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• pp.46-49
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• 2003

전원장치의 소형 경량화 및 고효율화를 위한 핵심 기술인 변압기를 설계 및 제조하기 위해 넓은 유효단면적을 가진 평면 자성체와 편편하고 넓은 도체를 이용하여 고주파 손실을 감소시켜 고주파 대역용 전원장치에 채용 가능한 입력 220 V, 출력 15V, 300 W급 포워드(Forward) 평면 변압기를 설계 및 제조하고 전자기적 특성과 입출력 신호 특성을 측정하였다. 1차 코일과 2차 코일의 권선수는 각각 15회와 2회 그리고 여자(demagnetizing) 권선은 15회로 설계하였으며, 변압기의 총 발열은 $44.78^{\circ}C$로 설계 및 제작하였다. 스위칭 주파수 100kHz에서 1.65mH의 인덕턴스 값을 얻었으며, 100 V의 입력전압에 대하여 13 V의 안정한 구형 출력파형을 얻었다. 따라서 스위칭 듀티(duty)가 최고 0.4로 설계되었기 때문에 설계 목표한 15 V 출력에 유사한 전압을 나타내어 평면 변압기의 설계 방법을 확립하였으며, 평면 변압기의 응용 가능성을 확인할 수 있었다.

• Computational Structural Engineering
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• v.11 no.4
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• pp.287-294
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• 1998

입면의 형태가 임의의 층에서 큰 차이를 보이는 3차원 비정형 setback 구조물의 동적 거동 특성과 이들 구조물의 동적 거동에 미치는 바닥 슬래브의 면내 변형 효과를 분석하였다. 비정형 setback 구조물의 전반적인 동적 거동특성을 분석하기 위하여 베이스 부분의 평면적과 타워 부분의 평면적 비(R?), setback 발생위치(L?)등을 매개 변수로 사용하였다. 48개의 비정형 setback 구조물들에 대한 해석 수행 결과 setback 구조물은 정형 구조물에 비해 횡방향 1차 모드의 유효 모드 중량(effective modal weight)이 작게 나타나는 경향을 보이기 때문에 setback 구조물의 동적 거동을 파악하기 위해서는 등가 정적 해석법 대신에 동적 해석을 수행할 필요가 있음을 알 수 있었다. 바닥슬래브의 면내 변형은 보다 긴 구조물의 고유 진동 주기값을 가져오며 모드 순서 및 모드 형상에도 변화를 준다. 이러한 사실은 바닥슬래브의 면내 변형으로 인하여 횡방향 저항 요소들간의 전단력 분포와 층 변위가 영향을 받을 수 있다는 것을 의미한다. 이러한 현상은 횡방향 저항 요소들간의 강성 차가 심한 프레임-전단벽 시스템에서 두드러지게 나타난다.

• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.6
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• pp.1-7
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• 2010

University dormitory has some weaknesses against disaster such as fire because of high population density and strict control of access in night time. The purpose of this study is suggestion of a guide of effective floor plan for improvement of evacuation safety. Plans for preventing disasters are studied and evacuation safeties are analysed using network model analysis method according to plan types. The weakness of disaster prevention is quantified, and effectiveness of bidirectional evacuation is confirmed. The circuit type floor plan shows best evacuation characteristics and this result is anticipated to be adopted to design process of new dormitories and will contribute to improvement of evacuation safety.

• Tunnel and Underground Space
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• v.18 no.4
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• pp.252-262
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• 2008

In the uniaxial compressive test of a single specimen of transversely isotropic rock, its 5 independent elastic constants can not be defined since maximum 4 independent strain measurements are available theoretically. In order to solve this problem, one equation proposed by Saint Venant in 19C and confirmed by Lekhnitskii through the test experiences has been used for long time. Accordign to authors' experiences, however, this equation turned out to give erroneous elastic constants in some cases. Three new equations are suggested and their compatibilities are discussed in this paper. As the results of the analyses of the models, Lekhnitskii's suggested equation is effective for the specimen with the high dip angle whereas it results in the large erred output for that with dip angle less than $25{\sim}30$. It was found that the effectivenesses of three suggested equations and their compatibilities are subject to the dip angle and not to the amounts of elastic constants. Guide map to the selection of the compatible one of those suggested equations is presented as a result of the study.

• Proceedings of the Optical Society of Korea Conference
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• 2008.07a
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• pp.169-171
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• 2008

마이켈슨 간섭계 시스템에 두 개의 Convex Lens를 추가함으로서 평면파 참조광을 유지 시키며, 물체에 조사되는 물체광의 조사면적을 변화시킬 수 있는 새로운 형태의 마이켈슨 간섭계를 제작 하였다. 새로운 형태의 마이켈슨 간섭계를 반사형 디지털 홀로그래피 현미경 시스템(Digital Holography Microscope System)에 적용하여 촬상소자(CCD: Charge Couple Device)에 홀로그램 기록 시 기록 가능한 CCD의 유효 영역과 재생 가능 영역에 대해 연구를 하였다

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.9
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• pp.1968-1974
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• 1997

In this paper, the spectral domain approach is employed to investigate the characteristics of symmetrical and asymmetrical broadside-coupleed coplanar waveguides(BSC-CPW). These structures have large even(c)-odd(.pi.) mode-velocity ratio, suitable for wide-band and tight-coupling microwave circuit design. Efficient design parameters can be obtained from the effective dielectric constants and characteristic impedances calculated by varying the strip widths and slot widths in the BSC-CPW structure.

• Korean Journal of Applied Biomechanics
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• v.19 no.1
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• pp.59-66
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• 2009

The purpose of this study was to evaluate flatness of swing plane and determine swing plane type using 3-D swing plane analysis from young elite male golf players. This study also investigate the possibility of determination of swing plane using other kinematic parameters except flatness. As results, no correlations was found between flatness and handicap. Comparison of flatness between single plane and multiple plane swing group were performed and found a significant difference. The error range of flatness, 10cm, which was used for distinguish swing plane type was effective since significant differences were found at MB, EB, and EF. These differences were typical characteristics to classify two swing styles. Other kinematic parameters such as unit vector components of shaft and displacement of shaft end point also compared per event but found no significant differences. However, the moving patterns of these parameters during a golf swing showed such characteristics of each swing plane type well that these parameters could be used to determine swing style as an indirect barometers.

• Journal of Korean Society for Geospatial Information Science
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• v.19 no.1
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• pp.97-103
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• 2011

LiDAR system has become a popular tool for generating 3D surface data such as Digital Surface Model. Extraction of valuable information, such as digital building models, from LiDAR data has been an attractive research subject. This research addresses to extract planar patches from LiDAR data. Planar patches are important primitives consisting of man-made objects such as buildings. In order to determine the best fitted planes, this research proposed a method to reduce/eliminate the impact of the outliers and the intersection areas of two planes. After finishing plane fitting, planar patches are segmented by pseudo color values which are calculated by determined three plane parameters for each LiDAR point. In addition, a segmentation procedure is conducted using the pseudo color values to find planar patches. This paper evaluates the feasibility of the proposed method using both airborne and terrestrial LiDAR data.