• Journal of Korean Association for Spatial Structures
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• v.3 no.4 s.10
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• pp.23-35
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• 2003

• Magazine of korean Tunnelling and Underground Space Association
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• v.21 no.1
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• pp.6-17
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• 2019

• Magazine of korean Tunnelling and Underground Space Association
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• v.21 no.3
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• pp.9-25
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• 2019

• Magazine of korean Tunnelling and Underground Space Association
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• v.26 no.3
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• pp.33-41
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• 2024

• Proceedings of the Optical Society of Korea Conference
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• 2000.02a
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• pp.284-285
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• 2000

광굴절률 현상은 optical signal processing과 홀로그램 기억소자로 널리 응용 될 수 있기 때문에 지금까지 광범위하게 연구되어져 왔다. 광굴절률 현상에서 중요한 변수는 빛이 있는 동안 drift, diffusion 과 photovoltaic current와 같은 전하 운반 메카니즘을 통해서 local charge의 재분포에 따른 공간전하장(Space-charge field, $E_{sc}$ )이다. 지금까지 single beam에 의한 공간전하장을 측정하는 방법으로 birefringenc $e^{1.2}$ 와 interference metho $d^{3}$을 이용하여 굴절률 변화를 측정함으로써 얻을 수 있었다. 그러나 이런 방법들은 공간전하장의 변화를 측정하기위해서 전기광학계수를 측정하여 얻는 간접적인 방법이고 또한 실험방법도 다소 복잡하다. 따라서 본 투고에서는 이미 발표된 광굴절률 현상시 제 2 고조파 세기(SHG)의 변화로부터 공간전하장을 간단하게 측정하는 방법을 이용하여 congruent, MgO가 4mole%, F $e_2$O가 0.1mole% 첨가된 LiNb $O_3$ 단결정의 공간전하장에 대해서 연구를 하였다. 이 방법은 전기광학물질인 LiNb $O_3$에서 SHG 위상정합조건이 dc 전기장에 의존하는 성질을 이용한 것이다. 그리고 온도가 일정할 경우 전기장의 변화에 따라 SHG의 크기가 변함을 이용하였다. (중략)

• Magazine of korean Tunnelling and Underground Space Association
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• v.9 no.3
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• pp.32-35
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• 2007

• Proceedings of the Korean Information Science Society Conference
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• 2002.10c
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• pp.247-249
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• 2002

최근 3D 공간 객체의 효율적인 표현을 위해, 3D 연산 및 다차원 인덱싱 기법에 관한 연구가 활발히 진행되고 있다. 또한 이러한 인덱스나 연산을 기반으로 많은 응용프로그램들이 개발되고 있다. 그러나, 대부분의 응용프로그램들은 단순히 비공간 속성에 대한 질의를 기반으로 한 3D 객체의 시각화에만 치중하고 있기 때문에, 3D 공간 객체에 관한 분석 기능을 제대로 지원하지 못하고 있다. 따라서, 이 논문에서는 3D 공간 객체에 관한 효율적 분석 기능을 제공할 수 있는 3D 공간 연산 처리기를 설계 및 구현하였다. 기존 시스템과의 상호운용을 위해서, 제안한 연산 처리기는 OpenGIS의 2차원 기하 객체 모텔을 3차원으로 확장한 3D 기하 객체 모델을 기반으로 하였다. 또한 빠른 공간 연산을 수행하기 위해 인덱스와 연동하여 구현하였다. 이 연산 처리기는 3D GIS에 적용될 경우, 효율적인 공간 분석 기능을 제공할 수 있다.

• The korean journal of orthodontics
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• v.37 no.6
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• pp.407-420
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• 2007

The aim of this study was to compare the differences in closing extraction spaces between maxillary first premolar and second premolar extractions using 3-dimensional finite element analysis (FEA). Methods: Maxillary artificial teeth were selected according to Wheeler's dental anatomy. The size and shape of each tooth, bracket and archwire were made from captured real images by a 3D laser scanner and FEA was performed with a 10-noded tetrahedron. A $10^{\circ}$ gable bend was placed behind the bull loop on a $0.017"{\times}0.025"$ archwire. The extraction space was then closed through 12 repeated activating processes for each 2mm of space. Results and Conclusions: The study demonstrated that the retraction of anterior teeth was less for the second premolar extraction than for the first premolar extraction. The anterior teeth showed a controlled tipping movement with slight extrusion, and the posterior teeth showed a mesial-in rotational movement. For the second premolar extraction, buccal movement of posterior teeth was highly increased.

• Spatial Information Research
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• v.21 no.5
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• pp.43-51
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• 2013

In this study, the concept of spatial big data and effective ways to build a spatial big data system are presented. Big Data is defined as 3V(volume, variety, velocity). Spatial big data is the basis for evolution from 3V's big data to 6V's big data(volume, variety, velocity, value, veracity, visualization). In order to build an effective spatial big data, spatial big data system building should be promoted. In addition, spatial big data system should be performed a national spatial information base, convergence platform, service providers, and providers as a factor of production. The spatial big data system is made up of infrastructure(hardware), technology (software), spatial big data(data), human resources, law etc. The goals for the spatial big data system build are spatial-based policy support, spatial big data platform based industries enable, spatial big data fusion-based composition, spatial active in social issues. Strategies for achieving the objectives are build the government-wide cooperation, new industry creation and activation, and spatial big data platform built, technologies competitiveness of spatial big data.

• Journal of the Korean Geographical Society
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• v.44 no.3
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• pp.301-322
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• 2009

This paper is an attempt to explore semiotic representations of subway space as the urban machine space of local mobility in terms of space, time and place. For this, the second section of the paper reviews the contours of the urban space of mobility in terms of 'machine space', 'non-place' and 'cognitive map'. The third section interprets the sings of 'spatial' and 'temporal' representations of subway space in Daegu, and suggests the implications of the semiotic representations. It is uncovered that various sign-scapes which coexist in the subway space in coordinated or contradictory ways product the space into multiple and complex techno-social spaces. That is, the spatio-temporal representations of the subway space form the space of 'non-place' on the one hand and the space of 'place' on the other hand, and involve the spatialization of 'memory' on the one hand and the spatialization of 'forgetting' on the other hand. Thus, the subway space should be regarded to be not only the space of 'mobility' which people move in and through, but also the space of 'identity' which has effects on the ways for them to see the machine space and its urban space.