• Journal of Mechanical Science and Technology
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• 제20권12호
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• pp.2034-2042
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• 2006

In this study, a complete 3D surface reconstruction method is proposed based on the concept that the vertices, of surface model can be completely matched to the unstructured point cloud. In order to generate the initial mesh model from the point cloud, the mesh subdivision of bounding box and shrink-wrapping algorithm are introduced. The control mesh model for well representing the topology of point cloud is derived from the initial mesh model by using the mesh simplification technique based on the original QEM algorithm, and the parametric surface model for approximately representing the geometry of point cloud is derived by applying the local subdivision surface fitting scheme on the control mesh model. And, to reconstruct the complete matching surface model, the insertion of isolated points on the parametric surface model and the mesh optimization are carried out. Especially, the fast 3D surface reconstruction is realized by introducing the voxel-based nearest-point search algorithm, and the simulation results reveal the availability of the proposed surface reconstruction method.

• 한국인터넷방송통신학회논문지
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• 제9권6호
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• pp.89-94
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• 2009

노드들이 무선으로 연결되어 통신하는 점에서 Ad-Hoc과 비슷한 점을 가지고 있는 Wireless Mesh Network는 하위 단말에 대한 기본 연결구조(Infrastructure)를 제공하는 것에 중점을 두고 있다. Wireless Mesh Network의 노드는 이동이 거의 없으며 데이터 흐름이 많고 QoS를 만족시켜야 히는 트래픽이 많이 존재하므로 데이터 전송을 위한 성능이 좋은 경로를 선택해야만 한다. 본 논문에서는 Wireless Mesh Network의 라우팅 방법을 위해 제안한 ETX, ETT 그리고 WCETT가 가지는 간섭 문제를 해결하기 위해 물리적인 간섭모텔을 적용하였다. 보다 향상된 간섭 측정으로 성능이 좋은 경로를 선택하기 위한 ETI(Expected Transmission Interference)를 제안하였고, 실험을 통해 성능이 향상됨을 보였다.

• 한국CDE학회논문집
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• 제8권4호
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• pp.270-277
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• 2003

In two dimensional mechanical design analysis, quadrilateral element mesh is preferred because it provides more accurate result than triangular element mesh. However, automation of quadrilateral element mesh generation is much more complex because of its geometrical complexities. In this study, an automatic quadrilateral element mesh generation algorithm based on the boundary normal offsetting method and the boundary decomposition method is developed. In so doing, nodes are automatically placed using the boundary normal offsetting method and the decomposition method is applied to decompose the designed domain into a set of convex subdomains. The generated elements are improved by relocation of the existing nodes based on the four criteria - uniformity, aspect ratio, skewness and taper degree. The developed algorithm requires minimal user inputs such as boundary data and the distance between nodes.

• 대한치과보철학회지
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• 제25권1호
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• pp.355-362
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• 1987

본 실험의 목적은 치아 회분이 입자 크기에 따라 골형성에 어떠한 영향을 주며 순수 합성수산화 apatite인 calcitite와는 어떠한 차이가 있는가를 평가하기 위하여 수행하였다. 이를 위하여 200mesh와 40mesh의 치아 회분말과 40mesh calcitite를 잡종견의 신선한 발치와에 매식후 1주, 2주, 3주, 4주에 각각 희생하여 임상, X-선상 및 현미경적으로 관찰한 바 다음과 같은 결론을 얻었다. 1. 모든 경우에 조직의 거부반응이 없었다. 2. 40mesh치아 회분의 경우가 200mesh의 치아회분의 경우 보다 골 형성 능력이 현저히 높았다. 3. 40 mesh 치아회분과 calcitite 모두 비교군에 비하여 골 형성이 지연되었다. 4. 40 mesh 치아 회분과 calcitite의 골 형성 능력은 유사하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.1-6
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• 2003

The purpose of the present study is to investigate the capillary heat transportation limitation in heat pipe according to the change of screen mesh wick porosity. Diameter of pipe was 6 mm, and mesh numbers are 100, 150, 200 and 250 and water was selected as a working fluid. According to the change of wick porosity and mesh number, the capillary pressure, pumping pressure, liquid friction coefficient in wick, vapor friction coefficient, and capillary heat transportation limitation are analyzed by theoretical design method of a heat pipe. As some results, the capillary heat transportation limitation in screen mesh wick heat pipe is largely affected by wick porosity and mesh number.

• International Journal of Contents
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• 제5권4호
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• pp.1-6
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• 2009

In this paper, we propose a mesh smoothing method for mesh models with noise. The proposed method enables not only the removal of noise from the vertexes but the preservation and smoothing of shape recognized as edges and comers. The magnitude ratio of 2D area and 3D volume in mesh data is adopted for the smoothing of noise. Comparing with previous smoothing methods, this method does not need many iteration of the smoothing process and could preserve the shape of original model. Experimental results demonstrate improved performance of the proposed approach in 3D mesh smoothing.

• 한국인쇄학회지
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• 제29권3호
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• pp.125-132
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• 2011

Is very simple in tension work of screen mesh for effective printing if worker uses screen mesh of player who desire at screen print process. General method is methods that use mesh of player who want on screen frame as screen plate because tensioned. The single layer screen plate was made from one sheet screen mesh and the double layer screen plate was made from two sheets screen mesh overlapped. The thickness of sensitive emulsion applied to double layer screen plate is more thicker than two time s of thickness of emulsion applied to single layer screen plate. It seems that the sensitive emulsion inserted between an upper layer and a lower layer of double layer screen mesh.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2007년도 가을 학술발표논문집 Vol.34 No.2 (D)
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• pp.556-559
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• 2007

Due to its ease of deployment, low cost, self-configuring and self-healing capabilities, Wireless Mesh Networks (WMNs) have emerged as a key technology to be used in a wide scale applications in personal, local, campus, and metropolitan areas. Security and more specifically privacy is an important issue in this type of multi-hop WMN which has given a little attention in the research community. We focus on privacy compromise of a mesh client in a community mesh network that may lead an attacker to reveal mesh clients identity. his other profiles and gain information about mobility. In this paper. we have presented an authentication mechanism with the aid of blind signature that ensures a mesh client to anonymously authenticate itself with a nearby mesh router and thereby preserve identity privacy We have also presented the security and performance analysis of the proposed scheme.

• 한국농공학회지
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• 제37권2호
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• pp.21-30
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• 1995

In order to save time and efforts in generating finite element meshes in irregular houndaries of domains, it is needed to develop an automatic mesh-generator which can hoth promote the accuracy of solutions and reduce the run-time in operating finite ele- ment models. In this study, the advancing front technique of triangular mesh generation and the transforming technique from triangular meshes to quadrilateral meshes were used to de- velop a computer program for the automatic triangular and quadrilateral meshes in the mixed shape. Furthermore, to enhance the quadrilateral mesh quality, the techniques of Laplancian smoothing and interior mesh modification were employed. The mesh genera- tor was applied to evaluate its applicability to irregular and complex geometries such as Nakdong river bay. In has hoen shown that the automatic mesh generator developed is capable of automatically generating meshes for irreguiar and complex geometries with high qualities of meshes and with the simple input data of arbitrarily specified nodal spacing in bound- aries.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2001년도 봄 학술발표회 논문집
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• pp.351-358
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• 2001

In this study, for the investigation of effects of several parameters, such as fluid mesh boundary size, cylinder or block shape, dimensions of depth, breadth and length at free suface, and fluid mesh element size to the depth direction on a reliable shock response of finite element model under underwater explosion with consideration of the bulk cavitation analysis of a simplified surface ship was carried out using the LS-DYNA3D/USA code. The shock responses were not much affected by the fluid mesh parameters. The computational time was greatly dependent on the number of DAA boundary segments. It is desirable to reduce the DAA boundary segments in the fluid mesh model, and it is not necessary to cover the fluid mesh boundary to or beyond the bulk cavitation zone just for the concerns about an initial shock wave response. It is also the better way to prefer cylinder type of the fluid mesh model to the block one.