• Nuclear Engineering and Technology
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• 제52권11호
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• pp.2630-2637
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• 2020

The structure design of divertor Multi-Functional Maintenance Platform (MFMP) actuated by hydraulic system for China Fusion Engineering Test Reactor (CFETR) was introduced in this paper. The model of MFMP was established according to maintenance requirements. In this paper, Newton-Euler method and the improved virtual work principle were used, the equivalent driving force of each actuator was obtained through the equivalent Jacobian inverse matrix derived from velocity relationship among the components. The accuracy of the model was verified by ADAMS simulation. The stability control of the heavy-duty components driven by hydraulic cylinders based on Newton-Euler method and improved virtual work principle was established.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.685-686
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• 2006

Recently, various AR-based product design methodologies have been introduced. In this paper, we propose technologies for enhancing robust augmentation and immersive realization of virtual objects. A robust augmentation technology is developed for various lighting conditions and a partial solution is proposed for the hand occlusion problem that occurs when the virtual objects overlay the user' hands. It provides more immersive or natural images to the users. Finally, vibratory haptic cues by page motors as well as button clicking force feedback by modulating pneumatic pressures are proposed while interacting with virtual widgets. Also our system reduces gabs between modeling spaces and user spaces. An immersive game-phone model is selected to demonstrate that the users can control the direction of the car in the racing game by tilting a tangible object with the proposed augmented haptic and robust non-occluded visual feedback. The proposed methodologies will be contributed to the immersive realization of the conventional AR system.

• 한국건설관리학회논문집
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• 제10권4호
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• pp.101-110
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• 2009

본 연구는 기존 시공단계 중심의 VR시뮬레이션 활용체계를 설계단계까지 확장하여 도로의 최적 설계정보 지원을 위한 시각화 분석 기능을 개발하는 것이 목적이다. 연구에서는 설계지원을 위한 VR기능으로 도보 선형(alignment)에 의한 토공 시뮬레이션, 대안 노선 선정 시뮬레이션 구조물 타입 선정 시뮬레이션 및 지하시설물 분석 시뮬레이션 기능들을 제안하고 있다. 이러한 VR시뮬레이션 기능을 통해 노선 및 토공 상태의 시각적 확인이 가능하고, 대안 노선의 가상적인 모의 배치를 수행함으로써 최적 설계노선을 선정할 수 있다. 이를 위해 본 연구에서는 도로설계정보 지원을 위한 VR시뮬레이션 기능 개발 방법론 및 시스템(VR Presenter)을 구현하며, VR기능을 적용한 개선된 도로설계 프로세스를 제안하고 있다.

• 한국CDE학회논문집
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• 제17권3호
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• pp.175-187
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• 2012

The BIM simulation systems involve inefficient aspects in delivering real world circumstances because they are operated in the virtual reality (VR) environment without representing the job-site operations. Differently from VR, augmented reality (AR) enhances the reflection of job-site reality to virtual environment. AR influences architecture, design and construction. This reality replaces or merges with the normal physical world and it can be tailored to enhance comprehension for specific design and construction activities. The main objective of this research is to develop an AR-based decision support system for free-form buildings design/construction/maintenance processes. Haewoojae, a free-form housing building built in Seoul area is identified as a model building to generate the system. Seventeen engineers, who are masters or doctorate graduate students at the S university in Seoul and have been working in the Korean construction industry for more than 10 years are invited to validate the system's appropriateness and usability in comparison with its development objectives.

• 정보교육학회논문지
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• 제21권5호
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• pp.583-593
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• 2017

초보자들을 위한 프로그래밍 교육의 어려움을 극복하기 위해 UMC(Use-Modify-Create) 학습, 디자인 기반학습, 발견학습, 놀이학습 등 다양한 학습전략을 적용한 연구들이 이루어지고 있다. 이에 본 연구에서는 학습자의 컴퓨팅 사고 향상을 위해 HVC(History-VR Coding-Collaboration) 학습전략 모델을 개발하였다. HVC 모델은 블록형태의 결합 모듈로 구성되어 있으며 이를 12차시로 구성된 스토리텔링 기반의 가상현실 블록 프로그래밍 교육과정을 개발하여 적용하였다. 연구 결과 HVC 모델 및 SW교육 프로그램이 학습자의 컴퓨팅 사고 향상에 유의미한 차이를 보였다.

• 대한기계학회논문집A
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• 제36권11호
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• pp.1463-1471
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• 2012

본 논문은 3 축 영상 장치를 기존의 2 축 경계 로봇에 적용하는 설계안을 제시하고 이러한 기동형 경계 로봇의 영상 정보를 이용한 목표 추적 알고리즘을 제안하였다. 또한 가상 시뮬레이션을 이용하여 목표 추적 알고리즘을 검증하였다. 목표추적 알고리즘에서는 카메라 영상의 중심과 카메라 영상으로 포착된 목표물 중심 사이의 위치 에러를 이용하여 영상 장치의 목표 지향 벡터를 획득하고, 역기구학을 이용하여 획득한 목표 지향 벡터를 생성해 낼 수 있는 기동형 경계 로봇의 팬, 틸트 회전 요구 각도와 카메라 영상의 안정화를 위한 롤 회전 요구각도를 계산하였다. MATLAB 과 ADAMS 를 이용하여 기동형 경계 로봇의 가상 모델을 생성하고, 가상의 목표물의 움직임에 대한 가상 모델의 운동을 확인하여 영상 기반의 목표 추적 알고리즘을 검증하였다.

• Bulletin of the Korean Chemical Society
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• 제28권6호
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• pp.947-952
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• 2007

Mycobacterium tuberculosis is a pathogen responsible for 2-3 million deaths every year worldwide. The emergence of drug-resistant and multidrug-resistant tuberculosis has increased the need to identify new antituberculosis targets. Acetohydroxy acid synthase, (AHAS, EC 2.2.1.6), an enzyme involved in branched-chain amino acid synthesis, has recently been identified as a potential anti-tuberculosis target. To assist in the search for new inhibitors and “receptor-based” design of effective inhibitors of tubercular AHAS (TbAHAS), we constructed four different structural models of TbAHAS and used one of the models as a target for virtual screening of potential inhibitors. The quality of each model was assessed stereochemically by PROCHECK and found to be reliable. Up to 89% of the amino acid residues in the structural models were located in the most favored regions of the Ramachandran plot, which indicates that the conformation of each residue in the models is good. In the models, residues at the herbicide-binding site were highly conserved across 39 AHAS sequences. The binding mode of TbAHAS with a sulfonylurea herbicide was characterized by 32 hydrophobic interactions, the majority of which were contributed by residue Trp516. The model based on the highest resolution X-ray structure of yeast AHAS was used as the target for virtual screening of a chemical database containing 8300 molecules with a heterocyclic ring. We developed a short list of molecules that were predicted to bind with high scores to TbAHAS in a conformation similar to that of sulfonylurea derivatives. Five sulfonylurea herbicides that were calculated to efficiently bind TbAHAS were experimentally verified and found to inhibit enzyme activity at micromolar concentrations. The data suggest that this time-saving and costeffective computational approach can be used to discover new TbAHAS inhibitors. The list of chemicals studied in this work is supplied to facilitate independent experimental verification of the computational approach.

• 한국실내디자인학회:학술대회논문집
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• 한국실내디자인학회 2008년도 춘계학술발표대회 논문집
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• pp.179-183
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• 2008

A variety of design processes from 2D graphic to 3D models are meeting improved consumers' confidence of modern clients. However, the current design methods are limited to meet consumers' needs and express a design concept what a designer wants to show. Therefore the study here tries a test of hybrid space simulation combined with previous models and digital media technology, which can be used for multiple contents. The study can contribute to suggesting virtual space simulation that can help clients' spatial understanding in this media era and deliver emotional language of designers as well by utilizing the strong point of multi-sensible media.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1994년도 Proceedings of the Korea Automatic Control Conference, 9th (KACC) ; Taejeon, Korea; 17-20 Oct. 1994
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• pp.324-327
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• 1994

In this paper, a new design method of variable structure model following control system(VSMFCS) for robot manipulators is proposed. The proposed controller overcomed reaching phase problem by using function augmenting scheme to the sliding surface. Therefore, it can be guaranteed that the overall system always has a robust property against parameter variations and external disturbances. Furthermore, the proposed controller does not use the model state, .chi.$_{m}$, different from other previous works. Regardless of not using the model state, the model following error dynamics, virtual dynamics, is shown to be globally exponentially stable. The efficiency of the proposed method has been demonstrated by an example.e.

• The Journal of Advanced Prosthodontics
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• 제12권3호
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• pp.107-113
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• 2020

PURPOSE. The aim of this study was to examine the importance of the defect-free scanning of a scan body by assessing the accuracy of virtual implant positioning in computer-aided design (CAD) software when the scan body image is improperly scanned. MATERIALS AND METHODS. A scan body was digitized in a dentiform model using an intraoral scanner, and scanned images with differing levels of image deficiency were generated: 5%, 10%, and 15% deficiency in the flat or rounded area. Using a best-fit image matching algorithm on each of the deficient scan body images, corresponding virtual implants were created. The accuracy of the implant position was evaluated by comparing the linear and angular discrepancies between the actual and virtual positions of the implant. Kruskal-Wallis tests and Mann-Whitney U tests with Bonferroni correction were used to determine the statistical differences among the seven scanned image deficiency groups (α=.05). RESULTS. In general, the linear and angular discrepancies of the implant position in the software increased as the deficiency of the scan body images increased. A 15% scan body image deficiency generated larger discrepancies than deficiency of 5% and 10%. The difference of scan defect position, flat or rounded area, did not affect the accuracy of virtual implant orientation at 5% and 10% deficiency level, but did affect the accuracy at 15% deficiency level. CONCLUSION. Deficiencies in the scanned images of a scan body can decrease the accuracy of the implant positioning in CAD software when the defect is large, thus leading to the incorrect fabrication of implant prostheses.