• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.7
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• pp.22-34
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• 2020

Three-dimensional (3D) computer-aided design (CAD) models require different levels of detail (LODs) depending on their purpose. Therefore, it is beneficial to automatically simplify 3D CAD assembly models to meet the desired LOD. Feature-based 3D CAD assembly models typically have the lowest and highest feasible limits of LOD during simplification. In order to help users obtain a feasible simplification result, we propose a method to simplify feature-based 3D CAD assembly models by determining the lowest and highest limits of LOD. The proposed method is verified through experiments using a simplification prototype implemented as a plug-in type module on Siemens NX.

• International conference on construction engineering and project management
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• 2011.02a
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• pp.157-161
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• 2011

BIM having started from architecture is being used in civil structure, but there are very few examples despite its effectiveness. In this paper, based on BIM technology, it is presented the method and result of developing web-based 5D system connecting cost, schedule and 3D model from the cable-stayed bridge. Through the system, the user can understand easily schedule on specific time and during some period and extract cost directly. This system also can manage various data types such as drawings, 3D models, documents and photos, for enhanced communication between stakeholders.

• The Journal of the Korea Contents Association
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• v.6 no.11
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• pp.302-309
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• 2006

This paper propose a practical algorithm to reuse and expand the objects. This algorithm is based on the Motion Path Modification rules. We focus on reusing of the existing motions for synthesizing new motions for the objects. Both the linear and the nonlinear curve-fitting algorithm are applied to modify an animation by keyframe interpolation and to make the motion appear realistic. We also proposes a framework of the scenario-based 3D image synthesizing system that allows common users, who envision a scenario in their minds, to realize it into segments of a cool animation. The framework is useful in building a 3D animation in game programming with a limited set of 3D objects.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2022.06a
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• pp.836-838
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• 2022

3D Point Cloud는 3D 콘텐츠를 더욱 실감 나게 표현하기 위한 데이터 포맷이다. Point Cloud 데이터는 3차원 공간상에 존재하는 데이터로 기존의 2D 영상에 비해 거대한 용량을 가지고 있다. 최근 대용량 Point Cloud의 3D 데이터를 압축하기 위해 V-PCC(Video-based Point Cloud Compression)와 같은 다양한 방법이 제시되고 있다. 따라서 Point Cloud 데이터의 원활한 전송 및 저장을 위해서는 V-PCC와 같은 압축 기술이 요구된다. V-PCC는 Point Cloud의 데이터들을 Patch로써 뜯어내고 2D에 Projection 시켜 3D의 영상을 2D 형식으로 변환하고 2D로 변환된 Point Cloud 영상을 기존의 2D 압축 코덱을 활용하여 압축하는 기술이다. 이 V-PCC로 변환된 2D 영상은 기존 2D 영상을 전송하는 방식을 활용하여 네트워크 기반 전송이 가능하다. 본 논문에서는 V-PCC 방식으로 압축한 V3C 데이터를 방송망으로 전송 및 소비하기 위해 MPEG Media Transport(MMT) Packet을 만드는 패킷화 방안을 제안한다. 또한 Server와 Client에서 주고받은 V3C(Visual Volumetric Video Coding) 데이터의 비트스트림을 비교하여 검증한다.

• The Journal of the Korea Contents Association
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• v.11 no.11
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• pp.91-101
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• 2011

This research aims to suggest web-based 3D face modeling system for hairline modification surgery. As public interests in beauty regarding face escalate with era of wide persoanl mobile smart iCT devices, need for medical information system is urgent and increasing demand. This research attempted to build 3D facing modeling library deploying conventional technology and proprietary software available. Implications from the our experiment found that problems and requirement for developing new web based standard. We suggest new system from our experiment and literature review regarding relevant technologies. Main features of our suggested systems is based on studies regarding hair loss treatment such as medical science, beauty studies and information technology. This system processes input images of 2D frontal and profile pictures of face into 3D face modeling with mesh-data. The mesh data is compatible with web standard technology including SVG and Canvas Tag supported natively by HTML5.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1615-1618
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• 2005

In this paper, implementation of object-based multiview 3D display using object segmentation and adaptive disparity estimation is proposed and its performance is analyzed by comparison to that of the conventional disparity estimation algorithms. In the proposed algorithm, firstly we can get segmented objects by region growing from input stereoscopic image pair and then, in order to effectively synthesize the intermediate view the matching window size is selected according to the extracted feature value of the input stereo image pair. Also, the matching window size for the intermediate view reconstruction (IVR) is adaptively selected in accordance with the magnitude of the extracted feature value from the input stereo image pair. In addition, some experimental results on the IVR using the proposed algorithm is also discussed and compared with that of the conventional algorithms.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.706-708
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• 2005

MMORPG게임의 구현에 있어서 가장 큰 문제의 하나는 서버와 연결된 클라이언트들 사이의 동기화이다. 이를 위해서 MMORPG게임에서는 grid-based filtering을 적용하여 동기화 문제를 해결하고 있다. 그러나 MMORPG게임의 형태가 이인칭 관점 시점의 2D에서 일인칭 관점의 시점의 3D 게임으로 변함에 따라서 grid-based filtering으로 인한 동기화는 낭비적인 요소를 포함하게 되었다. 즉 일인칭 관점시점의 3D게임에서는 가까운 거리의 캐릭터 사이에도 주변 장애물의 영향으로 비 가시관계에 놓임에 따라서 동기화의 필요성이 없어지는 경우가 생기게 된다. 따라서 본 논문에서는 일인칭 관점 게임의 3D MMORPG게임에서 컴파일 시 각 셀을 중심으로 가시성 테스트를 수행하여 가시영역내의 셀들만을 동기화 대상으로 지정한 후 게임 진행 시 현재 셀 속의 캐릭터들에게 동기화 대상으로 설정된 셀 속의 클라이언트들만을 동기화 시켜줌으로서 통신량을 줄여주는 방법을 제안한다.

• Journal of the Korean Society of Radiology
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• v.10 no.8
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• pp.571-576
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• 2016

3D printing has recently been used in various fields. Among various applications, 3D face data must be generated for 3D face printing. A laser scanner is used to acquire 3D face data, but there is a restriction that a person should not move during scanning. In this paper, we propose a 3D face modeling method based on a single image and a face transformation system to use the generated 3D face for virtual cosmetic surgery. We have defined facial feature points from the 3D face database for 3D face data generation. After extracting feature points from a single face image, 3D face of the input face image is generated corresponding to the 3D face feature points defined from the 3D face database. After 3D face modeling, 3D face modification part is applied for use such as virtual cosmetic surgery.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.289-292
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• 2010

In this paper we proposed web-based educational multimedia contents development method using Web 3D technology and implemented web 3D contents for use at the education field. A implementation of contents is composed of modeling to specific entity in 3D shape, convert modeling data to enable data at web and include in webpage. A practical use of contents on this research can provide more advanced user experience and immersion.

• International Journal of Contents
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• v.9 no.1
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• pp.18-25
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• 2013

Recently, augmented reality has been proved immensely useful on a day to day basis when tied with location-based technology. In this paper, we present a new method for displaying augmented reality contents on mobile devices. We add 3D models on the view of the camera and use location-based services, motion sensors to calculate the transformation of models. Instead of remaining at a fixed position on camera view while moving around a 3D model, the model rotates on display in the opposite direction that the user is walking. We also design client as a ubiquitous client to reduce constraints on disk space and memory capacity on mobile devices. Implementation results show effective use in creating GPS-based 3D view augmented reality contents for Smart Mobile Devices.