• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1625-1628
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• 2003

Recently the VR technique has evolved into a mixed reality (MR) technique, in which a user can observe a real world in front of him/her as well as virtual objects displayed. This has been realized by the employment of a see-through type HMD (S-HMD). We have been developing a mixed reality space employing the MR technique. The objective of our study is to realize a virtual human that acts as a man-machine interface in the real space. It is important in the study to create a virtual human acting naturally in front of a user. In order to give natural motions to the virtual human, we employ a developed motion capture technique. We have already created various 3-D human motion models by the motion capture technique. In this paper, we present a technique for creating a virtual human using a human model provided by a computer graphics software, 3D Studio Max(C). The main difficulty of this issue is that 3D Studio Max(C) claims 28 feature points for describing a human motion, but the used motion capture system assumes less number of feature points. Therefore a technique is proposed in the paper for producing motion data of 28 feature points from the motion data of less number of feature points or from incomplete motion data. Performance of the proposed technique was examined by observing visually the demonstration of some motions of a created virtual human and overall natural motions were realized.

• 디자인학연구
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• 제16권4호
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• pp.25-36
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• 2003

3차원 가상 공간에서의 네비게이션은 복잡한 인지 과정을 이해하고 미리 면밀히 설정되어야 하는 과정이다. 상호작용적 3차원 영상의 대중화 시대를 맞아 현재의 다양한 데스크 탑 소프트웨어는 개발자에게 보다 쉬운 저작 환경을 제공하고 있지만 사실 그동안의 체계적 개념 연구는 여건이 갖추어진 특정 기관에 국한되어 이루어져 온 것이 현실이다. 따라서 본 논고에서는 그 간에 대학 및 업체에서 연구 발표한 가상현실 연구의 사례들을 중심으로 보다 창의적인 네비게이션 구현에 근간이 되는 주요 개념들과 네비게이션의 구체적 구현을 지원 해줄 수 있는 직접적 및 간접적 요소들을 분석 및 고찰하고 있다.

• 대한치과의사협회지
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• 제52권1호
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• pp.17-26
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• 2014

Computerized 3D virtual dental models are currently available, and their use has started to improve treatment outcomes. The accuracy of digital models has been demonstrated by many studies and various intra-oral scanners are innovated for short scanning time and high precision. Recently, a digital model was combined with a high technology computer-driven system, which was developed for the application of a digital set-up and indirect bonding of lingual attachments. In this section, virtual treatment planning using a virtual set-up program is be introduced, and the clinical applications and accuracy of computer-generated indirect bonding are discussed.

• 패션비즈니스
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• 제16권2호
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• pp.151-162
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• 2012

The industry-wide development of digital technologies has also affected the textile and fashion industries immensely. The applications of 3D technology, virtual reality, and/or augmented reality systems have helped to create novel fashion brands based on the marriage of IT and textile/fashion industries. 3D digital virtual clothing systems have been developed to help the textile and fashion industries in terms of the planning, manufacturing, marketing and sales sectors. So far, most of the development effort for the 3d virtual clothing systems has been focused on the woven fabrics. The characteristics of woven fabrics differ from those of knitted fabric. Since the physical structures and mechanical properties of the knitted fabrics are definitely different from those of woven fabrics, the simulation process for the knitted fabrics should follow different approaches. The loops in a knitted fabric deform easily. The deformation results in a readily stretchable fabric appearance. Cloth simulation mostly employs models that approximate the mechanical properties of linear elastic planes. This simulation scheme does not, however, describe well enough the behavior of knitted fabrics, which deviate largely from the linear isotropic material characteristics. This study aims at characterizing the tensile deformation and surface textures of a knitted fabric product. Tensile deformation curves for the wale, course, and bias direction are analyzed. The surface texture of the knitted fabric is analyzed by using a 3-dimensional scanning device.

• 대한치과기공학회지
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• 제38권3호
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• pp.217-224
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• 2016

Purpose: This study aimed to generate 3-D occlusal curvatures and evaluate the relationship between the occlusal curvatures and mandibular occlusal morphology factors. Methods: Mandibular dental casts from 25 young adult Korean were scanned as a virtual dental models with a 3-D scanner(Scanner S600, Zirkonzahn, Italy). The curve of Spee, curve of Wilson, and Monson's sphere were generated by fitting a circle/sphere to the cusp tips using a least-squares method. The mandibular mesiodistal cusp inclination, buccolingual cusp inclination, and tooth wear parameters were measured on the prepared virtual models using RapidForm2004(INUS technology INC, Seoul, Korea). Wilcoxon signed-rank test was performed to test side difference, and Spearman's rank correlation coefficients were investigated to verify the correlation between occlusal curvatures and correlated factors (a=0.05). Results: The mean radii of curve of Spee were $83.09{\pm}33.94$ in the left side and $79.00{\pm}28.12mm$ in the right side. The mean radii of curve of Wilson were $66.82{\pm}15.87mm$ in the mesial side and $47.87{\pm}9.40mm$ in the distal side with significantly difference between mesiodistal sides(p<0.001). The mean radius of Monson's sphere was $121.85{\pm}47.11mm$. Most of the cusp inclination parameters showed negative correlation for the radius of Monson' sphere(p<0.05). Especially, the buccolingual cusp inclinations in mesial side of molar showed high correlation coefficients among the factors(p<0.05). Conclusion: The radius of Monson's sphere was greater than the classical 4-inch values, and the buccolingual cusp inclinations in mesial side of molar can be considered as one of the main factors correlating with the radius of Monson's sphere.

• 한국의류학회지
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• 제44권5호
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• pp.923-949
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• 2020

Improving work efficiency and satisfying customers through personalized services is becoming more important in an increasingly competitive hair industry. Wearables may help to improve hair designers' work efficiency and customer satisfaction by analyzing customer and hair designers' conditions and provide hair stylingrelated data. However, there is limited research on developing wearables for hair designers (WHDs), and many existing wearables were developed without understanding user needs and perceptions. This research investigated preferences, perceptions, and intentions on WHDs based on hair designers in the U.S., which is the largest hair market. Specific design options that hair designers preferred and possible options to meet requirements that hair designers expect for wearables were identified and suggested in WHD design guidelines. Second, most people preferred a WHD design of a black-colored bracelet/watch that can be a necklace designed with preferred functions; in addition, 3D virtual images and 3D printed models were prototyped. Third, developed designs were evaluated. More than 70% of users were satisfied and considered it as useful and easy to use, with an intention to purchase. The results are expected to provide insights to designers when developing WHDs.

• The Journal of Advanced Prosthodontics
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• 제10권5호
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• pp.367-373
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• 2018

PURPOSE. To evaluate the fit of a crown produced based on a 3D printed model and to investigate its clinical applicability. MATERIALS AND METHODS. A master die was fabricated with epoxy. Stone dies were fabricated from conventional impressions (Conventional stone die group: CS, n=10). Digital virtual dies were fabricated by making digital impressions (Digital Virtual die group: VD, n=10). 3D data obtained from the digital impression was used to fabricate 3D printed models (DLP die group: DD, n=10, PolyJet die group: PD, n=10). A total of 40 crowns were fabricated with a milling machine, based on CS, VD, DD and PD. The inner surface of all crowns was superimposed with the master die files by the "Best-fit alignment" method using the analysis software. One-way and 2-way ANOVA were performed to identify significant differences among the groups and areas and their interactive effects (${\alpha}=.05$). Tukey's HSD was used for post-hoc analysis. RESULTS. One-way ANOVA results revealed a significantly higher RMS value in the 3D printed models (DD and PD) than in the CS and DV. The RMS values of PD were the largest among the four groups. Statistically significant differences among groups (P<.001) and between areas (P<.001) were further revealed by 2-way ANOVA. CONCLUSION. Although the fit of crowns fabricated based on the 3D printed models (DD and PD) was inferior to that of crowns prepared with CS and DV, the values of all four groups were within the clinically acceptable range (<$120{\mu}m$).

• 국제학술발표논문집
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• The 1th International Conference on Construction Engineering and Project Management
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• pp.1181-1186
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• 2005

In many construction projects, progress and efficiency are hampered by poor communication of discipline-specific models. For example, architects use 2D or 3D CAD models and builders use CPM diagrams, Gantt charts, and spreadsheets to show their view of the project. Nowadays, advanced computer visualization tools, 4D CAD or VR, can show these disparate models to understand cross-disciplinary impacts of design and construction decisions. In Korea, several leading companies have tried to apply these tools to their pilot projects from the design phase to the maintenance phase. These companies have expected that more project stakeholders could understand a construction schedule more quickly and completely with 4D visualization than with the traditional construction management tools. However, modeling of the 4D CAD or VR can be quite time-consuming and expensive to generate manually and has therefore limited the spread and use of these models. In order to adopt widely those models in construction industry, the areas that those tools could support to take large benefits in diverse functional areas of construction management need to be analyzed. In this study, researchers analyze the usefulness and limitations of the 4D models and VR in the construction industry, develop the strategy of application priority, and improve the 4D modeling method.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.73.2-73
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• 2001

Nowadays, one of the major technical issues in manufacturing is how to implement an virtual plant as an well-designed, integrated environment for sharing information and engineering collaboration among diverse engineering activities. The systematic approaches to make a virtual plant based on a 3-dimensional CAD, cell and line simulation, database and internet technologies are proposed in this paper. To do that, measuring and 3D CAD modeling technologies of many equipments, facilities and structures of the building are developed, effective management of information including models and related files in WWW environment is implemented, and precise simulations of unit cell and whole structured plant are performed. For the beginning of implementing a Virtual Automotive Plant, the Virtual Plant for the Body Shop of a Korean automotive company is constructed and implemented, Using this Virtual Plant ...

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.590-595
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• 2007

It is important to predict the collision behavior of a train consist to improve its crashworthiness. To analyze crash behavior of train, four kinds of methods are mainly used so far. The first is method using multibody dynamics to predict the gross motion of the train set. The second uses 3D FE model to apply the section analysis method in order. The third is used to deduce design specification and evaluate the crashworhiness of a train by using 1D model. The last is to constitute 2D model to check overriding and coupling devices. The train evaluation procedures are so complex that it is difficult to understand or deal with. In this study, VTM for railway train was introduced to simplify the procedures. VTM involves 3D models, 1D models and dynamic components such as suspension and coupling. The method using hybrid concept model makes it possible to do all the things that are mentioned above. To analyze crash behavior tendency of VTM, the model was simulated and the simulation results were discussed.