• The Transactions of the Korea Information Processing Society
• /
• v.3 no.7
• /
• pp.1894-1905
• /
• 1996

Delauuany triangulation which is the dual of Dirichlet tessellation is not affine invariant. In other words, the triangulation is dependent upon the choice of the coordinate axes used to represent the vertices. In the same reason, Delahanty tetrahedrization does not have an affine iveariant transformation property. In this paper, we present a new type of tetrahedrization of spacial points sets which is unaffected by translations, scalings, shearings and rotations. An affine invariant tetrahedrization is discussed as a means of affine invariant 2 -D triangulation extended to three-dimensional tetrahedrization. A new associate norm between two points in 3-D space is defined. The visualization of the structure of tetrahedrization can discriminate between Delaunay tetrahedrization and affine invariant tetrahedrization.

• Journal of the Korea Computer Graphics Society
• /
• v.2 no.2
• /
• pp.11-20
• /
• 1996

The numerous application of scattered data include the modeling and visualization of physical phenomena. A tetrahedrization is one of pre-processing steps for 4-D surface interpolation. In this paper, various tetrahedrization methods are discussed including, Delaunay, least squares fitting, gradient difference, and jump in normal direction derivatives. This paper discriminates the characteristics of tetrahedrization through visualizing tetrahedral domain. This paper also, provides the tool that can compare and analyze the quality of 4-D space approximation over tetrahedral domain numerically, as well as graphically.

• Proceedings of the KIEE Conference
• /
• 2005.07d
• /
• pp.2864-2866
• /
• 2005

색역폭 사상은 디스플레이 장치간의 색재현성 차이를 보정하기 위한 기법이다. 본 논문에서는 사면체 보간에 의한 실시간 색역폭 사상을 제안하고자 한다. 기존의 제안된 육면체 보간 방식에 비해 이 논문에서 제안된 사면체 보간(tetrahedral interpolation) 방법은 색공간의 분할을 통해 분할된 각각의 사면체 색 공간에서 색역폭 사상이 수행됨으로서 왜곡이 감소되고 육면체 보간이 8개의 룩업테이블을 사용하는데 비해 4개의 룩업 테이블을 사용함으로서 실시간 처리속도의 향상과 하드웨어의 구현 시 비용절감을 기대할 수가 있다.

• Journal of Digital Contents Society
• /
• v.16 no.6
• /
• pp.909-916
• /
• 2015

This paper presents a method to display the 3D vector fields by analyzing phase space. This method is based on the connections between ordinary differential equations and the topology of vector fields. The phase space analysis should be geometric interpolation of an autonomous system of equation in the form of the phase space. Every solution of it system of equations corresponds not to a curve in a space, but the motion of a point along the curve. This analysis is the basis of this paper. This new method is required to decompose the hexahedral cell into five or six tetrahedral cells for 3D vector fields. The critical points can be easily found by solving a simple linear system for each tetrahedron. The tangent curves can be integrated by finding the intersection points of an integral curve traced out by the general solution of each tetrahedron and plane containing a face of the tetrahedron.

• The Transactions of the Korea Information Processing Society
• /
• v.3 no.6
• /
• pp.1553-1567
• /
• 1996

The numerous applications surface interpolation include the modeling and visualization phenomena. A tetrahedrization is one of pre-processing steps for 4-D space interpolation. The quality of a piecewise linear interpolation 4-D space depends not only on the distribution of the data points in $R^2$, but also on the data values. We show that the quality of approximation can be improved by data dependent tetraheadrization through visualization of 4-D space. This paper discusses Delaunary tetrahedrization method(sphere criterion) and one of the data dependent tetrahedrization methods(least squares fitting criterion). This paper also discusses new data dependent criteria:1) gradient difference, and 2) jump in normal direction derivative.

• Journal of the Korean Geotechnical Society
• /
• v.17 no.5
• /
• pp.17-27
• /
• 2001

지하 굴착공동의 천장면에 형성되는 잠재적 키블록의 존재성과 운동학적 거동 양상 및 안정성을 해석적으로 분석할 수 있는 시스템을 개발하였다. 천장에서 측정된 절리들의 상대적인 위치와 방향성 자료를 이용하여 데이타베이스를 구축하였으며, 굴착설계도와 연계된 전산절리도를 작성하였다. 잠재적 키블록의 존재성과 거동양상은 사면체로 가정된 블록 옆면의 3차원 공간에서의 평면식을 절리의 방향성에 의거하여 구성하며 대수학적으로 분석되었다. 블록의 안정성 분석은 자중에 의해 미끄러짐이 발생되는 블록면의 공간 기하학적 특성을 고려하여 수행하였다. 개발된 분석시스템의 현장활용성을 검증하기 위하여 언양 자수정동굴에서 키블록 형성 및 거동양상을 조사하여 분석결과와 비교하였다.

• Journal of the Korea Computer Graphics Society
• /
• v.17 no.2
• /
• pp.45-53
• /
• 2011

This paper proposes a volume meshing method that fills the inside of an object with tetrahedra, of which dihedral angles are good. The suggested method is fast, stable and easy to implement It can also utilize an octree structure to space-efficiently fill an object with graded tetrahedra by reducing the total number of tetrahedra. To obtain a high-quality mesh with good dihedral angles, we restrict the octree such that any pair of neighboring cells only differs by one level. To efficiently construct a restricted-octree and generate a volume mesh from the octree, we utilize a signed distance field of an object on its bounded workspace. The suggested method can be employed in FEM-based simulation of large elasto-plastic deformation and tetrahedral-mesh-based simulation of fluid flow.

• The Transactions of the Korea Information Processing Society
• /
• v.6 no.4
• /
• pp.1081-1089
• /
• 1999

Volume data modeling is concerned with finding a mathematical function which represents the relationship implied by the 3D data. Modeling a volume data geometrically can visualize a volume data using surface graphics without voxelization. It has many merits in that it is fast and requires little memory. We proposes, a method based on wavelet transformation and tetrahedrization. we implement a prototype system based on the proposed method. Last, we evaluated the proposed method comparing it with marching cube algorithm. the evaluation results show that though the proposed method uses only 13% of the volume data, the images generated is as good as the images generated by the marching cubes algorithm.

• Tunnel and Underground Space
• /
• v.11 no.3
• /
• pp.270-278
• /
• 2001

Two numerical methods such as DEM and FDM were adopted to analysis of rock slope stability, of which dimensions are about 150 m(length), 58 m(height), 70°dip, in Halla limestone mine. For this rock slope stability analysis, strength reduction method was used to calculate the safety factor of slope through numerical method. To keep the rock slope safely, it is proposed to reduce the height of the rock slope from 58 m to 45 m and to reduce the angle of the slope from 70°to 55°, too.

• Tunnel and Underground Space
• /
• v.16 no.6 s.65
• /
• pp.451-466
• /
• 2006

Analysis of slope behavior concerning the structural characteristics of field rock mass can be processed by virtue of borehole information of joint orientation and position acquired from DOM drilled core. Anticipated sliding potential of pre-failed rock slope is analyzed and the regional slope instability is investigated by inspecting the hazardous joints and blocks the traces of which is projected on the cut-face. Cross section has been set at the center of rock slope and the traces of both joints and tetrahedral blocks, which potentially can induce the slope failure, are drawn to investigate the failure modes and the triggering mechanism. Automated monitoring system has been established to measure the slope movement and especially, inclinometer has been installed inside DOM borehole to analyze the slope movement by considering the internal rock structure. Algorithms for predicting the slope failure time have been reviewed and the significance of heavy rainfall on the slope behavior has been investigated.