• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2003년도 추계학술발표대회 논문집
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• pp.71-74
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• 2003

The cell modeling homogenization method to derive the constitutive equation considering the microstructures of the fiber reinforced composites has been previously developed for composites with simple microstructures such as 2D plane composites and 3D rectangular shaped composites. Here, the method has been further extended for 3D circular braided composites, utilizing B-spline curves to properly describe the more complex geometry of 3D braided composites. For verification purposes, the method has been applied for orthotropic elastic properties of the 3D circular braided glass fiber reinforced composite, in particular for the tensile property. Prepregs of the specimen have been fabricated using the 3D braiding machine through RTM (resin transfer molding) with epoxy as a matrix. Experimentally measured uniaxial tensile properties agreed well with predicted values obtained fer two volume fractions.

• 한국산학기술학회논문지
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• 제16권9호
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• pp.6019-6026
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• 2015

본 연구에서는 소량생산 및 개인 맞춤형 제작으로 매우 유용한 3D 프린팅 기술을 이용하여 자가 맞춤형 부목을 제작하고자 하였다. 방법으로는 3D 프린터를 이용하여 용융적층조형방식(fused deposition modeling)으로 부목을 제작하였으며, 재료는 열가소성 플라스틱 계열인 ABS(acrylonitrile butadiene styrene) 수지를 이용하였다. 부목의 모델링은 실제 인체의 손 부위 3차원 전산화단층영상을 이용하였으며 통풍이 가능하도록 설계하였다. 그 결과 실제 인체 손 모양과 일치하는 자기 맞춤형 부목이 성공적으로 출력되었다. 또한 기존 부목보다도 우수한 방사선영상을 획득할 수 있었다. 결론적으로 본 연구에서 제시한 3D 프린팅 사례는 ABS 수지를 이용한 용융적층조형방식의 유사한 구조물을 출력할 때 기초자료로 사용할 것으로 판단된다.

• 한국IT서비스학회지
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• 제15권3호
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• pp.71-95
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• 2016

In recent years, text mining has been used to extract meaningful insights from the large volume of unstructured text data sets of various domains. As one of the most representative text mining applications, topic modeling has been widely used to extract main topics in the form of a set of keywords extracted from a large collection of documents. In general, topic modeling is performed according to the weighted frequency of words in a document corpus. However, general topic modeling cannot discover the relation between documents if the documents share only a few terms, although the documents are in fact strongly related from a particular perspective. For instance, a document about "sexual offense" and another document about "silver industry for aged persons" might not be classified into the same topic because they may not share many key terms. However, these two documents can be strongly related from the R&D perspective because some technologies, such as "RF Tag," "CCTV," and "Heart Rate Sensor," are core components of both "sexual offense" and "silver industry." Thus, in this study, we attempted to discover the differences between the results of general topic modeling and R&D perspective topic modeling. Furthermore, we package social issues from the R&D perspective and present a prototype system, which provides a package of news articles for each R&D issue. Finally, we analyze the quality of R&D perspective topic modeling and provide the results of inter- and intra-topic analysis.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제15권9호
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• pp.705-709
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• 2009

본 논문에서는 직교하는 2장의 얼굴영상과 얼굴 특징 자동추출을 통하여 3차원 얼굴모델을 생성하는 기술을 제안한다. 제안하는 기술은 3차원 얼굴모델을 개인화하는 부분과 2장의 얼굴영상으로부터 얻은 텍스쳐 맵을 3차원 얼굴모델에 사상하는 부분으로 구성된다.

• 한국전자통신학회논문지
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• 제8권8호
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• pp.1187-1193
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• 2013

본 논문은 사실적인 3D 얼굴 모델링과 얼굴 표정 생성 시스템을 제안한다. 사실적인 3D 얼굴 모델링 기법에서 개별적인 3D 얼굴 모양과 텍스쳐 맵을 만들기 위해 Generic Model Fitting 기법을 적용하였다. Generic Model Fitting에서 Deformation Function을 계산하기 위해 개별적인 얼굴과 Generic Model 사이의 대응점을 결정하였다. 그 후, Calibrated Stereo Camera로부터 캡쳐 된 영상들로부터 특징점을 3D로 복원하였다. 텍스쳐 매핑을 위해 Fitted된 Generic Model을 영상으로 Projection하였고 사전에 정의된 Triangle Mesh에서 텍스쳐를 Generic Model에 매핑 하였다. 잘못된 텍스쳐 매핑을 방지하기 위해, Modified Interpolation Function을 사용한 간단한 방법을 제안하였다. 3D 얼굴 표정을 생성하기 위해 Vector Muscle기반 알고리즘을 사용하고, 보다 사실적인 표정 생성을 위해 Deformation 과 vector muscle 기반의 턱 rotation을 적용하였다.

• 한국BIM학회 논문집
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• 제4권3호
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• pp.1-9
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• 2014

As BIM application continues to increase in civil engineering, in this study, 3D information model for RC(Reinforced Concrete) bridge pylon was developed and verified its effectiveness at the structural-design stage. To define 3D information model of RC A-Type pylon, characteristics of pylon were analyzed and 3D model structure was constructed. The 3D information model, one of the core product of BIM, manages all information generated during all life-cycle of a structure and consequently maximizes the efficiency of utilizing information. Also, this study proposes interface module between input data in structural analysis and 3D model of RC pylon. The module can create the input data for non-linear structural analysis. It is essential to study on method of developing 3D information model and propose a structural analysis model by utilizing 3D model for the effective use of BIM techniques in construction industry. The results of this study can be used as the base data for developing the 3D information model of RC pylon in the structural analysis field.

• Journal of Computational Design and Engineering
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• 제2권1호
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• pp.67-72
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• 2015

Recently, along with the improvements of geometry modeling methods using sketch-based interface, there have been a lot of developments in research about generating surface model from 3D curves. However, surfacing a 3D curve network remains an ambiguous problem due to the lack of geometric information. In this paper, we propose a new algorithm for estimating the normal vectors of the 3D curves which accord closely with user intent. Bending energy is defined by utilizing RMF(Rotation-Minimizing Frame) of 3D curve, and we estimated this minimal energy frame as the one that accords design intent. The proposed algorithm is demonstrated with surface model creation of various curve networks. The algorithm of estimating geometric information in 3D curves which is proposed in this paper can be utilized to extract new information in the sketch-based modeling process. Also, a new framework of 3D modeling can be expected through the fusion between curve network and surface creating algorithm.

• 한국정밀공학회지
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• 제27권8호
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• pp.91-97
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• 2010

Micro-abrasive Jet Machining is one of the new technology which enables micro-scale machining on the surface of high brittle materials. In this technology it is very important to fabricate a mask that prevents excessive abrasives not to machine un-intend surface. Our previous work introduced the micro-stereolithography technology for the mask fabrication. And is good to not only planar material but also for non-planar materials. But the technology requires a 3 dimensional mask CAD model which is perfectly matched with the surface topology of parent material as an input. Therefore there is strong need to develop an automated modeling technology which produce adequate 3D mask CAD model in fast and simple way. This paper introduces a fast and simple mask modeling algorithm which represents geometry of models in voxel. Input of the modeling system is 2D pattern image, 3D CAD model of parent material and machining parameters for Micro-abrasive Jet Machining. And the output is CAD model of 3D mask which reflects machining parameters and geometry of the parent material. Finally the suggested algorithm is implemented as software and verified by some test cases.

• 국제초고층학회논문집
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• 제3권4호
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• pp.311-323
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• 2014

This paper introduces recent applications of three-dimensional building/construction data modeling (3D) and building information modeling (BIM) to large-scale complex building construction projects in Japan. Recently, BIM has been utilized as a tool in construction process innovation through planning, design, engineering, procurement and construction to establish a front-loading-type design building system. Firstly, the background and introduction processes of 3D and BIM are described to clarify their purposes and scopes of applications. Secondly, 3D and BIM applications for typical large-scale complex building construction projects to improve planning and management efficiency in building construction are presented. Finally, future directions and further research issues with 3D and BIM applications are proposed.

• 한국해양공학회지
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• 제25권3호
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• pp.47-52
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• 2011

3D geometric modeling has a lot of advantages in the field of design and manufacturing. Many manufacturing processes and production lines are using 3D geometric modeling technique. These help reduce the cost and time for manufacturing. The purpose of this study is the realization of a 3D cutting shape for an H-Beam used in ships and ocean plants. The complex 3D cutting shapes could be represented by using the boolean operation of basic figures. Graphic functions with parameters were used to simply define the basic figures. The developed system can show the complex cutting shape of an H-beam simply and quickly. This system can be utilized for the automatic cutting system for an H-beam.