• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.141-144
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• 2010

건설공사 프로젝트는 기획, 설계, 시공, 운영 및 유지관리 등 각 단계의 다양한 참여 주제에 의해 프로젝트가 진행되고 각 분야 간 원활한 의사소통을 통한 협업으로 일을 진행해 나간다. 그러나 각 단계별 커뮤니케이션이 원활히 이뤄지기가 힘들며, 이러한 단계별 분절의 가장 큰 이유 중 하나가 실제적 결과물은 3차원 기반인 것에 비해, 그 과정이 2차원 CAD 시스템에 의존하는 결과와 과정의 격차 때문이다. 그로 인해 각 관련 분야에서 발생되는 정보의 불확실성, 부정확성, 표현의 애매모함 등으로 인해 재작업 및 불필요한 작업이 빈번히 발생하여 전체적인 공정의 지연 및 비용의 문제, 결과물의 품질에 대한 문제가 발생하고 있다. 또한 도면에서의 한계점인 거리감, 공간감 등 실제 사람이 느끼는 Scale감을 알 수 없어 공간에 대한 이해도가 떨어지는 한계점을 극복하지 못하고 있으며 1인칭 작업운영 방식으로 인하여 협업 설계과정에서 원활한 팀워크를 유도 할 수 없다. 따라서 본 연구에서는 협업설계 과정에서 기본설계 단계를 지원하는 설계 도구로서 건축모델의 단순 시각화에서 벗어나 가상공간에서 몰입형 VR 시뮬레이션을 구현하기 위하여 프로토타입 응용을 개발 하였고, 이것을 "Digital Studio"에 구현하여 즉각적인 공간 시뮬레이션을 통하여 실제 시공 전에 문제점들을 검토 및 보완하고 전체적으로는 생산성 향상과 설계 과정 중 오류를 최소화하기 위한 VR시뮬레이션 시스템의 제안 및 Viewer 모듈을 개발 하였다.

• The Journal of Korean Academy of Prosthodontics
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• v.37 no.1
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• pp.71-92
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• 1999

This study is to analyze the stress and displacement on the jaws during the bilateral and unilateral clenching task on three dimensional finite element model of the dentated skull. For this study, the computed tomography(G.E.8800 Quick, USA) was used to scan the total length of human skull in the frontal plane at 1.9mm intervals. The CAD data were extracted from the tomograms through digitizer(Summa Sketch III, USA) and then reconstructed by means of the spline method in the CAD program. In this project, a commercial software I-DEAS(Master Series ver-sion 3.0, SDRC Inc, USA) was used for three-dimensional stress analysis on the finite element model. which consists of articular disc, maxilla, mandible, teeth, periodontal ligament and cranium. The results are as follows. ; 1. During the bilateral clenching, each major muscle forces caused high stresses on various areas of skull: masseter muscle on articular disc and teeth ; temporal muscle on mandible and periodontal ligament ; medial pterygoid muscle on the temporomandibular joint. During the unilateral clenching, masseter muscle induced the maximum stress ; medial pterygoid muscle the minimum stress. 2. During the bilateral clenching, higher compressive stresses on articular disc were generated by the masseter muscle and higher deformation occurred on the most front outer sites. And during the unilateral clenching, temporal muscle and medial pterygoid muscle exerted their forces to twist temporomandibular joint area of the balancing side and induced a higher compressive stresses on the front outer sites of articular disc. 3. During the bilateral clenching, the masseter muscle bended the mandible outwardly, and then caused tensile stresses on the lingual surface of mandibular symphysis. And the medial pterygoid muscle caused tensile stresses on the labial surface of mandibular symphysis. 4. When each muscles were simultaneously applied on jaws, a high stress and displacement took place on mandible rather than on the maxilla. Also, a high stress and displacement took place during the unilateral clenching rather than during the bilateral clenching.

• Journal of the Korea Institute of Building Construction
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• v.14 no.5
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• pp.407-413
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• 2014

Appropriate selection of lifting equipments for a high-rise building construction project is one of the important factors to the project's success. Proper position of a tower crane on a construction site is so important to be determined by an expert or an experienced construction manager who draws working range of a tower crane and moves it over 2D(dimensional) site layout plan. 3D CAD, BIM, and virtual reality are is used for building design and construction, but it is not usual to use them for temporary facility planning or selection of a tower crane. This study proposes a suitable method to use augmented reality to select proper position of tower cranes. An augmented reality prototype is implemented by Vuforia and Unity 3D on a smart device to verify the practicability of the proposed method. The prototype application installed on a smart device shows several tower cranes on different markers in a real architectural drawing to locate the proper tower crane.

• KIEAE Journal
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• v.16 no.1
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• pp.89-94
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• 2016

This study is part of three-dimensional(3D) heat transfer analysis program developmental process. The program is being developed without it's own built in 3D-modeller. So 3D-model must be created from another 3D-modeller such as generic CAD programs and imported to the developed program. After that, according to the 3D-geometric data form imported model, 3D-mesh created for numerical calculation. But the 3D-model created from another 3D-modeller is likely to have errors in it's geometric data such as mismatch of position between vertexes or surfaces. these errors make it difficult to create 3D-mesh for calculation. These errors are must be detected and cured in the pre-process before creating 3D-mesh. So, in this study four kinds of filters and functions are developed and tested. Firstly, 'vertex error filter' is developed for detecting and curing for position data errors between vertexes. Secondly, 'normal vector error filter' is developed for errors of surface's normal vector in 3D-model. Thirdly, 'intersection filter' is developed for extracting and creating intersection surface between adjacent objects. fourthly, 'polygon-line filter' is developed for indicating outlines of object in 3D-model. the developed filters and functions were tested on several shapes of 3D-models. and confirmed applicability. these developed filters and functions will be applied to the developed program and tested and modified continuously for less errors and more accuracy.

• Journal of the Korean Society of Clothing and Textiles
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• v.31 no.5 s.164
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• pp.692-704
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• 2007

Recently, Basic patterns with excellent body fitness and automation availability are required to be developed in order to automate the patterns of women's clothes. In this study, this reference points, reference lines and segments were fixed onto 3D scan data for the lower body the women in their twenties, they were directly spread out to be 2D flat pattern to facilitate development into the design of slacks adhered closely to the human body such as special and highly-functional clothes, and then slacks 2D pattern was developed for the purpose of seeking scientific approach to the development into basic form slacks and 3d emotional pattern. For conversion of 3D pattern into 2D flat pattern, reference points and segments were created by using Rapid Form of 3D shape analysis software, and triangle mesh of the body surface of the created shape was developed with Auto CAD 2005. The correspondence between slacks and human body was examined by the fixation of major reference lines. Specially, the wearing characteristics of slacks were considered by the fixation of side lines in consideration of posture. As a result of using the way of development to constantly maintain the length while 3D triangle mesh is converted into 2D flat mesh, the shape was shown to be excellently reproduced, and the area of flat pattern was increased compared to the shape of parting plane. Also, the sunk-in curve like the brief line of front crotch length needed a cutting line when it was closely adhered, when mesh was overlapped, and the pattern area was smaller compared to the actual shape.

• Journal of the Korean Society of Clothing and Textiles
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• v.33 no.1
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• pp.68-79
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• 2009

It is inevitable to have cutting line to get the 2D pattern from 3D body surface. In this paper the efficiency of curvature plot as a cutting line in the process of flattening 3D surface was investigated. As reference, basic clothing construction line was adopted to divide the 3D surface into small blocks to make the flattening process easy. Female dummy as well as human body were scanned and surface of the upper body was segmented using curvature plot and basic constructing line. 2D tight-fit pattern was developed using three software, the RapidForm 2004, 2C-AN and Yuka CAD. Gap between clothes and body, and the clothing pressure on the body was observed to determine the fit of the clothes. As results, clothes constructed with blocks divided by curvature plot displayed a similar level of tight fit as compared with those by basic construction line. It was found that curvature plot is effective method as a segmentation of the 3D surface even for the actual body which does not have any previous reference line. It is expected that application of curvature plot will be expanded in 3D apparel technology.

• Fashion & Textile Research Journal
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• v.21 no.4
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• pp.480-487
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• 2019

This study used 3D technology to develop a multi-functional sports brassiere with increased comfort and fit that can be worn as a base layer during exercise or as underwear. A 75A size industrial lingerie figure was used to develop a standard pattern. 3D tools for scanning and pattern making, such as Vivid 910, Geomagic Design X, 2C-AN and Yuka CAD were used. The sports brassiere was designed as a tank top style with dual structure and linings attached to a pad utilized with a sport brassiere mold cup. 3D outer and lining's pattern was differently developed in consideration of the body's curvature with pad's shape and structure. Shoulder and neck part reduction rates were adjusted to increase the neck areas fit that considered the nude pattern's structure due to uncomfortableness felt by wearers who were uncomfortable with the neck areas fit on existing brand products. The reduction rate was also set differently on each part. For example, the reduction rate on outer side panel was set strongly to increase the breast's volume. Two products, developed by a 3D sports brassiere and previously released product, were worn on 8 subjects in their 20's to evaluate fit, comfort, and purchase preferences. The evaluation proved that newly developed 3D products were superior to comparative products. The results of the clothing pressure measurement indicate that the newly developed sports brassiere's front part had less pressure on upper bust and shoulder areas compared to comparative products as well as showed less pressure on the back side, which shows improved wearing comfort compared to comparative products.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.5
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• pp.1269-1276
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• 2015

The mission capability of tank depends on its survivability. The survivability is ability for protection and tolerance by damage from threats. To improve the survivability of tank, we need an effectiveness analysis for loss of components, and accomplish performance enhancement using the result of analysis. In this paper, we develop a survivability analysis system for tank based on the importance. The importance numerically represents weight of each component which consisting of whole tank, also the importance is basic method of quantitative survivability analysis. To do this, we assign weight values to each component of tank, compose a weight tree, apply the importance calculation equation, and analyze the survivability of tank. Also we develop the system that consists of component structuralization and weight value setting program and survivability analysis and visualization program, and evaluate the system using implemented 3D CAD models of components of tank. The developed system apply to arrangement components.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.2
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• pp.135-146
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• 2020

To define an interface in a conventional level-set method, an analytical function must be revealed for an interfacial geometry. However, it is not always possible to define a functional form of level sets when interfaces become complex in a Cartesian coordinate system. To overcome this difficulty, we have developed a new level-set formalism that discriminates the interior from the exterior of a CAD modeled interface by parameterizing the stereolithography (STL) file format. The work outlined here confirms the accuracy and scalability of the hydrodynamic reactive solver that utilizes the new level set concept through a series of tests. In particular, the complex interaction between shock and geometrical confinements towards deflagration-to-detonation transition is numerically investigated. Also, a process of flame spreading and damages caused by point source detonation in a real-sized plant facility have been simulated to confirm the validity of the new method built for reactive hydrodynamic simulation in any complex three-dimensional geometries.

• Korean Journal of Construction Engineering and Management
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• v.10 no.6
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• pp.3-12
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• 2009

In order to effectively distribute the resources, it is very critical to understand the status or progress of construction site quickly and accurately. Augmented Reality (AR) can provide this situation with information which is convenient and intuitive. Conventional implementation of AR in outdoor or construction site condition requires additional sensors or markers to track the position and direction of camera. This research is aimed to develop the technologies which can be utilized in gathering the information of constructing or constructed buildings and structures. The AR technique that does not require additional devices except for the camera was implemented to simplify the system and improve utility in inaccessible area. In order to do so, the position of camera's perspective center and direction of camera was estimated using exterior orientation techniques. And 3D drawing model of building was projected and overlapped using this information. The result shows that by using this technique, the virtual drawing image was registered on real image with few pixels of error. The technique and procedure introduced in this paper simplifies the hardware organization of AR system that makes it easier for the AR technology to be utilized with ease in construction site. Moreover, this technique will help the AR to be utilized even in inaccessible areas. In addition to this, it is expected that combining this technique and 4D CAD technology can provide the project manager with more intuitive and comprehensive information that simplifies the monitoring work of construction progress and planning.