• The KIPS Transactions:PartC
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• v.18C no.5
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• pp.361-368
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• 2011

In this study, we present a method for efficiently aggregating networks state information required to determine feasible paths in transport networks that uses the source routing algorithm for hierarchical QoS routing. It is proposed to transform the full mesh topology whose Service Boundary Line serves as its logical link into the star topology. This is an aggregation method that can be used when there are two or more QoS parameters for the link to be aggregated in an asymmetric network, and it improves the information accuracy of the star topology. For this purpose, the Service Boundary Line's 3 attributes, splitting, joining and integrating, are defined in this study, and they are used to present a topology transformation method. The proposed method is similar to space complexity and time complexity of other known techniques. But simulation results showed that aggregated information accuracy and query response accuracy is more highly than that of other known method.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.5D
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• pp.527-532
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• 2012

Terrestrial LiDAR emerges as a main mapping technology for indoor 3D cadastre, cultural heritage conservation and, building management in that it provides fast, accurate, and reliable 3D data. In this paper, a new 3D modeling method consisting of segmentation stage and outline extraction stage is proposed to develop indoor 3D model from the terrestrial LiDAR. In the segmentation process, RANSAC and a refinement grid is used to identify points that belong to identical planar planes. In the outline tracing process, a tracing grid and a data conversion method are used to extract outlines of indoor 3D models. However, despite of an improvement of productivity, the proposed approach requires an optimization process to adjust parameters such as a threshold of the RANSAC and sizes of the refinement and outline extraction grids. Furthermore, it is required to model curvilinear and rounded shape of the indoor structures.

• Journal of Broadcast Engineering
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• v.27 no.5
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• pp.638-653
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• 2022

In this paper, we propose the new method of creating 3D virtual-human reflecting the pattern of clothes worn by the person in the high-resolution whole body front image and the body shape data about the person. To get the pattern of clothes, we proceed Instance Segmentation and clothes parsing using Cascade Mask R-CNN. After, we use Pix2Pix to blur the boundaries and estimate the background color and can get UV-Map of 3D clothes mesh proceeding UV-Map base warping. Also, we get the body shape data using SMPL-X and deform the original clothes and body mesh. With UV-Map of clothes and deformed clothes and body mesh, user finally can see the animation of 3D virtual-human reflecting user's appearance by rendering with the state-of-the game engine, i.e. Unreal Engine.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.8 no.4
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• pp.319-326
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• 2015

In this paper, a 3D mechanical model based on pulmonary nodule segmentation method is proposed. The proposed method has three main parts. First, an initial 3D mechanical model is generated. The model is made up of many triangle elements resulting in forming whole shape of the model as sphere. Second, points of the model are deformed, and finally internal and external energies according to each deformation are calculated. The internal energy is determined by the model shape, and the external energy is determined by intensity. After the model is deformed, the process of searching the minimum energy generated by the deformation is executed repetitively. If the model energy converges, the nodule is segmented by using the proposed model. The proposed method greatly improves the result compared with conventional methods.

• Journal of Korea Water Resources Association
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• v.51 no.10
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• pp.853-862
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• 2018

An adaptive cut-cell grid based 2D inundation analysis model, K-Flood, is developed in this study. Cut cell grid method divides a grid into a flow area and a non-flow area depending the characteristics of the flows. With adaptive mesh refinement technique cut cell method can represent complex flow area using relatively small number of cells. In recent years, the urban inundation modeling using high resolution and fine quality data is increasing to achieve more accurate flood analysis or flood forecasting. K-Flood has potential to simulate such complex urban inundation using efficient grid generation technique. A finite volume numerical scheme of second order accuracy for space and time was applied. For verification of K-Flood, 1) shockwave reflex simulation by circular cylinder, 2) urban flood experiment simulation, 3) Malpasset dam collapse simulation are performed and the results are compared with observed data and previous simulation results.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.10a
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• pp.615-618
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• 2001

본 논문은 기존의 3D 게임 엔진에 실시간으로 상호 작용이 가능하고 3D MMORPG(Massive Multi-play Online Role flaying Game) 게임에 적합한 가상 공간을 표현하기 위한 필요한 기술을 분석하고 이를 활용하려 한다. 기존의 머드 게임에 3 차원 기술을 적용하고, 3 차원 물체를 모델링 하는데 있어서 메쉬나 버텍스, 혹은 폴리곤으로 사실적인 지형 처리와 렌드링 속도 향상을 위하여 3 차원 개체의 폴리곤을 동적으로 생성시키고 가시성 판단이나 충돌 검출을 위한 방법으로 Height field 처리 기법과 거리에 변화에 따라 다르게 모델링 된 데이터를 선택적으로 사용하는 CLOD(Continuous Level of Detail) 처리 기법과 입체 컬링 방법으로 옥트리를 이용하여 가상공간을 분해하기 위한 자료 구조로 사용한다. 거리의 변화에 따라 지형을 표현하는 vertex 들을 병합 또는 삭제함으로써 그 표현의 정도를 동적으로 달리 할 수 있는 CLOD 를 이용하여 카메라의 위치와 방향에 따라 적절한 폴리곤을 생성해 낼 수 있다. 본 논문은 기존의 3 차원 공간을 표현하기 위하여 사용되고 있는 옥트리 구조를 이용하여 공간을 분할하고, 이를 세부 수준으로 나누어 처리하기 위한 LOD(Level of Detail)와 CLOD 개념을 이용하여 외부지형을 폴리곤으로 표현하는 방법에 대한 처리 기법과 가시성 판단이나 충돌 검출을 위한 방법을 제시하려 한다.

• Journal of Broadcast Engineering
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• v.11 no.4 s.33
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• pp.471-482
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• 2006

In this paper, we propose a new scheme to generate multi-view images utilizing depth map decomposition and adaptive edge smoothing. After carrying out smooth filtering based on an adaptive window size to regions of edges in the depth map, we decompose the smoothed depth map into four types of images: regular mesh, object boundary, feature point, and number-of-layer images. Then, we generate 3-D scenes from the decomposed images using a 3-D mesh triangulation technique. Finally, we extract multi-view images from the reconstructed 3-D scenes by changing the position of a virtual camera in the 3-D space. Experimental results show that our scheme generates multi-view images successfully by minimizing a rubber-sheet problem using edge smoothing, and renders consecutive 3-D scenes in real time through information decomposition of depth maps. In addition, the proposed scheme can be used for 3-D applications that need the depth information, such as depth keying, since we can preserve the depth data unlike the previous unsymmetric filtering method.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.2
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• pp.401-407
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• 2016

We can consider the following problems for two given points p and q in a simple polygon P. (1) Compute the set of points of P which are visible from both p and q. (2) Compute the set of points of P which are visible from either p or q. They are corresponding to the problems which are to compute the intersection and the union of two visibility polygons. In this paper, we consider algorithms for solving these problems on a reconfigurable mesh(in short, RMESH). The algorithm in [1] can compute the intersection of two general polygons in constant time on an RMESH with size O($n^3$), where n is the total number of vertices of two polygons. In this paper, we construct the planar subdivision graph in constant time on an RMESH with size O($n^2$) using the properties of the visibility polygon for preprocessing. Then we present O($log^2n$) time algorithms for computing the union as well as the intersection of two visibility polygons, which improve the processor-time product from O($n^3$) to O($n^2log^2n$).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.10B
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• pp.1937-1945
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• 1999

In paper, we propose a 3D polygonal mesh simplification technique based on vertex clustering. The proposed method differentiates the size of each cluster according to the local property of a 3D object. We determine the size of clusters by considering the normal vector of triangles and the vertex distribution. The subdivisions of cluster are represented by octree. In this paper, we use the Harsdorff distance between the original mesh and the simplified one as a meaningful error value. Because proposed method adaptively determine the size of cluster according to the local property of the mesh, it has smaller error as compared with the previous methods and represent the small regions on detail. Also it can generate a multiresolution model and selectively refine the local regions.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2008.11a
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• pp.117-120
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• 2008

본 논문은 스테레오 비디오 데이터 압축 및 복원을 위한 그리드(Grid) 기반 2D 워핑 방법을 제안한다. 스테레오 비디오에 대한 데이터 표현 방법으로 깊이지도 및 매쉬(mesh)를 이용한 방법이 주로 사용되어 왔으며 매쉬를 이용한 방법은 두 영상간의 매칭되는 노드를 이용하여 데이터 압축 효율을 높일 수 있다. 그러나, 두 영상에서 매칭되는 노드의 위치를 찾는 것은 매우 어려운 일일 뿐만 아니라 매쉬에 의해서 워핑된 영상과 목적이 되는 스테레오 영상의 좌측 또는 우측 영상간의 왜곡이 불가피하다. 따라서 이러한 왜곡을 보정하기 위하여 잔여영상(Residual image) 정보를 추가로 요구하게 된다.제안된 논문은 이러한 잔여영상 정보를 최소화 하기 위하여 반복적으로 2D워핑을 수행하며 최적화된 워핑 영상을 생성함으로써 목적영상과의 오차를 최소로 유지하여 추가정보인 잔여 영상의 데이터 용량을 최소화 한다. 전체영상에 대하여 2D워핑을 수행하며 각각의 노드를 변경하는 것은 많은 비용을 감수해야 하기 때문에 오차영역에 대하여 지역단위로 분할하고 단계적으로 최적화를 이루는 분할정복 방법을 사용하였다. 본 논문의 실험에서는 스테레오 영상에 대하여 각각의 신호대 잡음비(PSNR)를 통해 제안한 방법의 품질을 평가하였을 뿐만 아니라 기존의 메쉬 기반한 방법과 깊이지도를 이용한 방법과의 데이터량을 비교하였다. 실험결과를 통하여 제안한 방법의 데이터 압축의 효율성 및 품질의 우수성을 확인하였다.