• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.3
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• pp.1011-1020
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• 1991

본 연구에서는 하향유동영역에서 수직면으로부터 경사각이 60˚ 이하인 경사 등온면이 저온의 물속에 잠겨 있을때 일어나는 다중정상상태 영역을 밝혀내고, 이 영 역에서 경사각이 열전달, 온도분포, 속도분포, 부력분포 및 누셀트 수에 미치는 영향 을 구명하였다. 또 해석방법은 이제까지 발표된 연구결과와 비교검토하기 위하여 기 존 논문에서와 같이 상이해석을 사용하였다.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.526-526
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• 2016

고립파는 다른 파들과는 달리 파고만 주어지면 파형이 결정되고 변형 없이 장거리를 전파시켜 처오름높이를 가장 잘 재현할 수 있기 때문에 지진해일의 많은 연구에서 입사파로 사용되어 왔다. 본 연구에서는 한양대학교 수리학 및 해안공학 연구실에서 보유중인 서보-피스톤 타입 조파기로 고립파를 발생시켜 2차원 조파수조 내부에 설치되어있는 동해안 경사모형에서 각 수심 및 상대파고에 따른 고립파의 처오름높이 측정실험을 수행하였다. 다수의 파고계를 이용하여 각 구역에서 수심 및 상대파고에 따른 고립파의 파형을 측정하였고, 경사면에서 처오름높이 분포의 최대와 최소, 평균값을 측정하였다. 측정된 실험결과를 바탕으로 동해안에서의 고립파 처오름높이에 대해서 서술하였다.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.10
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• pp.777-788
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• 2006

This paper describes a displacement mapping technique which represents protruded shapes on the surface of an object. Previous approaches for image-based displacement mapping can represent only shapes depressed from the polygon surface. The proposed technique can represent shapes protruded from the underlying surface in real-time. Two auxiliary surfaces which are perpendicular to the underlying surface are added along the boundary of the polygon surface, in order to represent the pixels which overflow over the boundary of the polygon surface. The proposed approach can represent accurate silhouette of protruded shape. It can represent not only smooth displacement of protruded shape, but also abrupt displacement such as perpendicular protrusion by means of adding the supplementary texture information to the steep surface of protruded shape. By per-pixel instructions on the programmable GPU this approach can be executed in real-time. It provides an effective solution for the representation of protruded shape such as high-rise buildings on the ground.

• Proceedings of the Korea Water Resources Association Conference
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• 1990.07a
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• pp.205-212
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• 1990

• Proceedings of the Korea Water Resources Association Conference
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• 2002.05b
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• pp.1135-1140
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• 2002

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.6
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• pp.887-903
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• 2017

Lots of shallow tunnels are constructed in the mountainous areas where the stress distribution in the ground around tunnel is not simple, also the impact of stress conditions on the longitudinal load transfer characteristics is unclear. The tunnel construction methods and the ground conditions would also affect the longitudinal load transfer characteristics which would be dependant on the displacement patterns of tunnel face. Therefore, in this study, the slope of the ground surface was varied in $0^{\circ}$, $10^{\circ}$, $20^{\circ}$, $30^{\circ}$, and the longitudinal load transfer depended on the deformation conditions of tunnelface (that were maximum deformation on the top, constant deformation, and maximum deformation on the bottom), and the stress distribution at tunnelface. As results, when the tunnelface deformed, the earth presure on the tunnelface decreased and the load at tunnel crown increased. The load transferred on the crown was influenced by the earth presure on tunnel face. Smaller load would be transfered to the wide areas when the slope of ground surface decreased. When the slope of ground surface became larger, the longitudinal load transfer would be smaller and would be concentrated on tunnelface, In addition, the shape of the transferred load distribution in the longitudinal direction was dependant on the deformation shape of tunnelface. The deformation shape of tunnelface and stress conditions in longitudinal sections would affect the shape and the magnitude of the load transfer in the longitudinal directions.

• Korean Journal of Remote Sensing
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• v.37 no.5_3
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• pp.1425-1434
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• 2021

Continuous and periodic data acquisition must be preceded to maintain and manage the river facilities effectively. Adapting the existing general facilities methods, which include river surveying methods such as terrestrial laser scanners, total stations, and Global Navigation Satellite System (GNSS), has limitation in terms of its costs, manpower, and times to acquire spatial information since the river facilities are distributed across the wide and long area. On the other hand, the Mobile Mapping System (MMS) has comparative advantage in acquiring the data of river facilities since it constructs three-dimensional spatial information while moving. By using the MMS, 184,646,009 points could be attained for Anyang stream with a length of 4 kilometers only in 20 minutes. Levee points were divided at intervals of 10 meters so that about 378 levee cross sections were generated. In addition, the waterside maximum and average slope could be automatically calculated by separating slope plane form levee point cloud, and the accuracy of RMSE was confirmed by comparing with manually calculated slope. The reference slope was calculated manually by plotting point cloud of levee slope plane and selecting two points that use location information when calculating the slope. Also, as a result of comparing the water side slope with slope standard in basic river plan for Anyang stream, it is confirmed that inspecting the river facilities with the MMS point cloud is highly recommended than the existing river survey.

• Tunnel and Underground Space
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• v.29 no.5
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• pp.332-345
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• 2019

Maximum dip vector of individual joint plane, which can be uniquely defined on the hemispherical projection plane, has been established by considering its dip and dip direction. A new stereographic projection method for the rock slope analysis which employs the maximum dip vector can intuitively predict the failure modes of rock slope. Since the maximum dip vector is uniquely projected on the maximum dip point of the great circle, the sliding direction of discontinuity plane can be recognized directly. By utilizing the maximum dip vector of discontinuity both the plane sliding and toppling directions of corresponding blocks can be discerned intuitively. Especially, by allocating the area of high dip maximum dip vector which can form the flanks of sliding block the potentiality for the formation of virtual sliding block has been estimated. Also, the potentiality of forming the triangular-sectioned sliding block has been determined by considering the dip angle of joint plane the dip direction of which is nearly opposite to that of the slope face. Safety factors of the different-shaped blocks of triangular section has been estimated and compared to the safety factor of the most hazardous block of rectangular section. For the wedge analysis the direction of crossline of two intersecting joint planes, which has same attribute of the maximum dip vector, is used so that wedge failures zone can be superimposed on the stereographic projection surface in which plane and toppling failure areas are already lineated. In addition the maximum dip vector zone of wedge top face has been delineated to extract the wedge top face-forming joint planes the orientation of which provides the vital information for the analysis of mechanical behavior of wedge block.

• Journal of The Korean Association For Science Education
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• v.33 no.1
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• pp.193-207
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• 2013

The purpose of this study was to investigate middle school and science-gifted students' conceptions about motion of objects on the surface of the earth and the moon. The subjects were 61 first-, 51 second-, 51 third-year students, for a total of 163 in a middle school and 32 science-gifted students from a university-affiliated sciencegifted education center for secondary school students. The research contents were conceptions about motion of objects by the vertical direction, an inclined plane and horizontal plane on the surface of the earth and the moon. The questions were as follows: If two balls, same size but different mass, were put on, thrown over, by the vertical direction, an inclined plane and a horizontal plane on the surface of the earth and the moon at the same time and speed, which one would arrive faster than the other?; In the same mass in the earth and the moon, how fast could the object reach to which location, the earth or the moon? The results showed that science-gifted students offer meaningful difference on the concept of objects in motion at the vertical direction, an inclined plane and a horizontal plane on the earth and at the vertical direction on the moon than general middle school students. There were meaningful difference on the vertical up direction, an inclined plane and a horizontal plane in the same situation in the earth and the moon. Finally, based on the results of our study, we discuss possible educational implications for teaching the concept of objects in motion.

• Korean Journal of Optics and Photonics
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• v.4 no.4
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• pp.390-396
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• 1993

When a one-dimensional telecentric paraxial holographic kinoform is used as a Fourier transform lens, we analyzed three surface-relief structures, i.e., plano-convex, convex-plano and biconvex shapes, employing exact raytracing method based on Snell's law. For the kinoform of E/8 and focal length of 15 mm, the number of zones, the thickness, and the slope of parabolic surfaces are varied by changing the refractive indicies of kinoform material and surrounding medium. It is found that biconvex shape gives the best results in general, although off-axis performance degrades in all cases as the slope of parabolic surfaces increases.