• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.22-25
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• 2001

A new mesh-topology model of IGBT is presented. It can be applied to the research of IGBT's static and dynamic latch-up (du/dt latch-up, overheat latch-up, overload latch-up, overvoltage latch-up) as well as the switching on-off behavior of the device. The overcurrent latch-up is analyzed.

• 전자공학회논문지D
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• 제34D권7호
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• pp.37-44
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• 1997

A dadaptive refinement tetrahedron mesh has been presented for using in full band GaAs monte carlo simulation. A uniform tetrahedron mesh is used without regard to energy values and energy variety in case of the past full band simulation. For the uniform tetrahedron mesh, a fine tetrahedron is demanded for keeping up accuracy of calculation in the low energy region such as .GAMMA.-valley, but calculation time is vast due to usin gthe same tetrahedron in the high energy region. The mesh of this study, thererfore, is consisted of the fine mesh in the low energy and large variable energy region and rough mesh n the high energy. The density of states (DOS) calculated with this mesh is compared with the one of the uniform mesh. The DOS of this mesh is improved th efive times or so in root mean square error and the ten times in the correlation coefficient than the one of a uniform mesh. This refinement mesh, therefore, can be used a sthe basic mesh for the full band GaAs monte carlo simulation.

• 태양에너지
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• 제19권3호
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• pp.43-51
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• 1999

Axisymmetric circular water jet impinges against rectangular heated surface with uniform hear flux and wire-mesh screens are set up in the nozzle-to-heater space to augment heat transfer. In the free jet region to be used them, pressure drop and intensive turbulence flow was brought up. When water jet system is not used wire-mesh screens, maximum heat transfer appears in the stagnation point and the secondary maximum appears X/D=4 but it disappears when they are is used. In the low velocity(Vo<6.0m/s), coarse mesh-screen enhanced heat transfer but fine mesh-screens inpeded heat transfer. In the high velocity(Vo>6m/s), all of them enhanced heat transfer. Average Nusselt number of experimental system to be used wire-mesh screens was promoted $4{\sim}6$times than that of simple water jet system. The stagnation heat transfer of experimental system to be used wire-mesh screens was augmented 6times that of simple water jet system.

• 대한기계학회논문집B
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• 제25권6호
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• pp.853-859
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• 2001

This paper describes the extended topological clean up procedures to improve the quality of unstructured triangular meshes. As a postprocessing step, topological improvement procedures are applied both for elements that are interior to the mesh and for elements connected to the boundary and then Laplacian-like smoothing is used by default. Previous clean up algorithms are limited to eliminate the nodes of degree 3,4,8,9,10 and pairs of nodes of degree 5. In this study, new clean up algorithms which minimize the triple connection structures combined with degree 5 and 7 (ie ; 5-7-5, 7-7-5, 7-5-7 etc) are added. The suggested algorithms are applied to two example meshes to demonstrate the effectiveness of the approach in improving element quality in a finite element mesh.

• 한국통신학회논문지
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• 제38C권7호
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• pp.587-594
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• 2013

웹 2.0의 발전과 스마트 디바이스의 보급은 제한적인 정보와 평면적인 서비스에 맞춤화된 기존의 웹서비스를 탈피하여 사용자가 원하는 다차원적인 정보와 다양한 서비스가 융합된 형태의 매쉬업 서비스를 탄생시키는 요인이 되었다. 매쉬업 서비스는 다양한 웹서비스가 융합된 서비스를 지칭하며 웹서비스의 인터페이스인 Open API를 통해 보다 손쉽게 지원되고 있다. 하지만 현재의 매쉬업 서비스는 개발자 중심의 서비스 제공 방식으로 인해 개인 맞춤화된 서비스를 제공 받고자 하는 다양한 사용자의 욕구를 충족시키지 못하는 문제점이 있다. 이러한 문제점 해결을 위해 매쉬업을 손쉽게 하는 매쉬업 프레임워크에 대한 연구가 다양하게 이루어지고 있지만 아직 그 수준이 미비하다. 본 논문에서는 동적으로 웹서비스를 합성하여 매쉬업 서비스를 제공하는 매쉬업 프레임워크의 요소기술로써 Open API 자동 합성을 위한 Open API 선별 기법 및 합성 방안에 대해 소개 하였다.

• 한국컴퓨터그래픽스학회논문지
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• 제15권2호
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• pp.1-8
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• 2009

본 논문에서는 사용자가 입력한 사람의 신체 모델과 모델에 입혀질 옷의 두 이미지를 입력으로 하여 2D상에서 옷과 모델이 잘 어울리게 입혀지는 가상의 드레스 업(Dress up)시스템을 제안한다. 첫 번째 단계에서는 골격 구조의 조인트 정보를 이용하여 옷 이미지를 크게 변형시킨다. 다음으로 옷의 경계에 있는 점들을 샘플링 하여 모델의 경계에 있는 점과 매칭 시키고 그 점들을 이용해 최적화 단계를 거쳐 최종적인 피팅 결과를 도출해 낸다. 두 단계를 거쳐 피팅 된 옷의 경우 평면적으로 보이기 때문에 부자연스러운 결과를 보이게 되므로 자연스러운 렌더링 결과를 위해서 이를 3D로 재구성 (reconstruction)시킨다. 재구성된 3D구조로부터 쉐이딩 정보를 가져와 다시 2D상에서 렌더링을 함으로써 최종적인 결과를 도출하게 된다. 본 연구에서 제안된 시스템을 통해 2D 기반의 가상 옷 시뮬레이션 결과를 얻을 수 있게된다.

• 한국항행학회논문지
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• 제15권4호
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• pp.616-625
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• 2011

본 연구에서는 지형을 Rendering 기법의 대표적인 방법인 Geometry Clipmaps와 ROAM 2.0을 분석하여 Rendering 연산에 소요되는 연산을 CPU가 아닌 GPU에 중점을 두어 보다 빠르고 넓은 가시화 영역을 보장하는 확장된 Geometry Clipmaps 알고리즘을 제안한다. 확장된 알고리즘은 LOD(Level of Detail)을 통한 각 레벨의 Mesh 구성 방법, 레벨간의 연결망 Mesh 구성 방법, VFC(View Frustum Culling)을 사용하여 Rendering을 최적화 할 수 있는 Mesh Block화 방안 그리고 최대 1m 해상도를 갖는 고해상도 영상 Mapping 방안 등을 포함하고 있다.

• 전기학회논문지
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• 제65권10호
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• pp.1786-1791
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• 2016

The damage has occurred inside the semiconductor pattern When using conventional wet station for semiconductor. It was used for electrolytic ion water generator in order to prevent damage to the semiconductor pattern. It was designed and developed a flow path electrode and the mesh electrode to check the efficiency of the electrode. And It confirmed the expected results through the simulation of the flow path. and ORP were measured in accordance with the current and voltage of mesh electrode and flow paht electrodes. Flow path electrode 22A is 3V, up to pH 9.8, the value of ORP-558mV was measured and the mesh electrode was measured up to pH 9.8, ORP -350mV.

• 한국CDE학회논문집
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• 제12권2호
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• pp.109-117
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• 2007

Three-dimensional mesh models have been widely used in various applications such as simulations, animations, and e-catalogs. In such applications the normal vectors of mesh models are used mainly for shading and take up the major portion of data size and transmission time paper over networks. Therefore a variety of techniques have been developed to compress them efficiently. In this paper, we propose the MOEC (Modified Octree Encoding Compression) algorithm, which allow multi lever compression ratios for 3D mesh models. In the algorithm, a modified octree has nodes representing their own positions and supporting a depth of the tree so that the normal vectors are compressed up to levels where the shading is visually indistinguishable. This approach provides efficient in compressing normals with multi-level ratios, without additional encoding when changing in compression ratio is required.

• 한국CDE학회논문집
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• 제11권1호
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• pp.20-26
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• 2006

This paper presents a procedure to compute pencil curves from a triangular mesh which is offset with the radius of a given ball-end mill. An offset triangular mesh has numerous self-intersections caused by an abundance of invalid triangles, which do not contribute to the valid CL-surface. Conceptually, we can obtain valid pencil curves by combining all intersections tying on the outer skin of the offset triangular mesh, i.e., the valid CL-surface. The underlying concept of the proposed algorithm is that visible intersections are always valid for pencil curves, because visible intersections lie on the outer skin of the offset model. To obtain the visibility of intersections efficiently, the proposed algorithm uses a graphics board, which performs hidden surface removal on up to a million polygons per second.