• The Journal of Advanced Prosthodontics
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• 제12권6호
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• pp.329-337
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• 2020

PURPOSE. To verify the influence of computer-aided design/computer-aided manufacturing (CAD/CAM) implant-supported prostheses manufactured with cobalt-chromium (Co-Cr) and zirconia (Zr), and whether ceramic application, spark erosion, and simulation of masticatory cycles modify biomechanical parameters (marginal fit, screw-loosening torque, and strain) on the implant-supported system. MATERIALS AND METHODS. Ten full-arch fixed frameworks were manufactured by a CAD/CAM milling system with Co-Cr and Zr (n=5/group). The marginal fit between the abutment and frameworks was measured as stated by single-screw test. Screw-loosening torque evaluated screw stability, and strain analysis was explored on the implant-supported system. All analyses were performed at 3 distinct times: after framework manufacturing; after ceramic application in both materials' frameworks; and after the spark erosion in Co-Cr frameworks. Afterward, stability analysis was re-evaluated after 106 mechanical cycles (2 Hz/150-N) for both materials. Statistical analyses were performed by Kruskal-Wallis and Dunn tests (α=.05). RESULTS. No difference between the two materials was found for marginal fit, screwloosening torque, and strain after framework manufacturing (P>.05). Ceramic application did not affect the variables (P>.05). Spark erosion optimized marginal fit and strain medians for Co-Cr frameworks (P<.05). Screw-loosening torque was significantly reduced by masticatory simulation (P<.05) regardless of the framework materials. CONCLUSION. Co-Cr and Zr frameworks presented similar biomechanical behavior. Ceramic application had no effect on the biomechanical behavior of either material. Spark erosion was an effective technique to improve Co-Cr biomechanical behavior on the implant-supported system. Screw-loosening torque was reduced for both materials after masticatory simulation.

• 한국통신학회논문지
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• 제27권10C호
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• pp.912-920
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• 2002

오늘날 컴퓨터와 통신 기술의 발달로 시간과 공간의 제약 없이 공유된 가상 공간에서 작업을 하는 컴퓨터 지원 협동 시스템(CSCW)이 등장하고 있다. 그러나 대부분의 시스템은 그룹웨어를 사용하고, 공유객체는 윈도우 탐색기 형태를 지니고 있고, CAD를 비롯하여 그래픽 분야의 시스템은 하드웨어와 응용 소프트웨어에 크게 의존하기 때문에 협동시스템이 많지 않다. 본 논문은 인터넷 웹 상에서 협동작업으로 이루어지는 CAD시스템의 3차원 솔리드 모델러를 제안한다. 이 시스템은 Java와 Java 3D API를 이용하여 개발함으로 플랫폼에 구애받지 않고, 특정한 3차원 그래픽스 소프트웨어 없이 인터넷망과 웹브라우저를 이용하여 공유된 가상 공간에서 협동작업이 이루어지도록 한다. 협동설계 참여자들은 인터넷을 통해 솔리드 모델러 서버에 접근하여 원하는 3D 도형을 생성하고 조작한다.

• 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.

• 한국정보통신학회논문지
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• 제4권4호
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• pp.767-773
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• 2000

오늘날 컴퓨터와 통신 기술의 발달로 시간과 공간의 제약 없이 공유된 가상 공간에서 작업을 하는 컴퓨터 지원 협동 시스템이 등장하고 있다. 하지만 하드웨어와 응용 소프트웨어에 크게 의존하고 있는 그래픽 분야와 CAD시스템은 그리 많지 않다 여기에서 제안하는 협동CAB시스템은 인터넷 망을 통하여 웹 상에서 플랫폼에 구애받지 않고 협동작업이 이루어지도록 하였고, VRML과 Java3D API를 이용하여 쉽게 도형을 생성하고 편집하여 전송하거나 출력ㆍ저장할 수 있도록 하며, 채팅을 통해 인터액티브한 작업이 가능하게 하고 있다. 이 시스템은 클라이언트/서버 구조로 클라이언트는 자바 애플릿을 통해 웹 상에서 접근하고 서버는 자바애플리케이션으로 접속을 통제하는 접속관리자, 작업 그룹의 동기화를 유지하며 공유작업공간을 확보하는 작업관리자, 그리고 3차원 도형 객체를 생성해 내는 솔리드 모델러로 이루어져 있다.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 1993년도 ACT 93
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• pp.729-733
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• 1993

• 한국전산구조공학회논문집
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• 제22권3호
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• pp.243-250
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• 2009

최근 기업에서는 설계 기간을 단축하기 위하여 기존의 CAD시스템들의 기능을 기업의 목적에 맞게 수정할 수 있는 커스터마이징 기술이 요구되고 있다. 이에 대부분의 상용 CAD시스템 개발회사들은 일련의 반복된 작업을 자동으로 수행할 수 있게 해주는 매크로나 외부 프로그램을 작성할 수 있도록 API를 제공하고 있다. 본 논문은 지식기반의 제품개발 체계를 구축하기 위하여 특정 부품의 정형화된 설계 규칙을 3D CAD 템플릿으로 개발하여 특정 모델링을 보다 편리하게 수행할 수 있도록 하는데 목적이 있다. 냉장고의 부품 설계에 요구되는 관련 수식, 데이터 및 설계지식을 Unigraphics의 UG/Open API를 이용하여 프로그램화하였고 그 개발사례를 제시하였다. 상용 CAD시스템에 연결하여 사용함으로써 설계 검증 및 설계 변경을 제품설계 업무에 효과적으로 적용하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.177-180
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• 2005

Three dimensional shaded images are standard visualization method for CAD models on the computer screen. Therefore, much of the effort in the visualization of CAD models has been focused on how conveniently and realistically CAD models can be displayed on the screen. However, shaded 3D CAD data images captured from the screen may not be suitable for some application areas. Technical document, either in the paper or electronic form, can more clearly describe the shape and annotate parts of the model by using projected 2D line drawing format viewed from a user defined view direction. This paper describes an efficient method for generating such a 2D line drawing data in the vector format. The algorithm is composed of silhouette line detection, hidden line removal and cleaning processes.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2007년도 춘계 학술대회논문집
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• pp.103-107
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• 2007

Computational Fluid Dynamics (CFD in short) approach is now playing an important role in the engineering process recently. Generating proper grid system for the region of interest in time is prerequisite for the efficient numerical calculation of flow physics using CFD approach. Grid generation is, however, usually considered as a major obstacle for a routine and successful application of numerical approaches in the engineering process. CFD approach based on the unstructured grid system is gaining popularity due to its simplicity and efficiency for generating grid system compared to the structured grid approaches. In this paper an automated triangular surface grid generation using CAD surface data is proposed According to the present method, the CAD surface data imported in the STL format is processed to identify feature edges defining the topology and geometry of the surface shape first. When the feature edges are identified, node points along the edges are distributed. The initial fronts which connect those feature edge nodes are constructed and then they are advanced along the CAD surface data inward until the surface is fully covered by triangular surface grid cells using Advancing Front Method. It is found that this approach can be implemented in an automated way successfully saving man-hours and reducing human-errors in generating triangular surface grid system.

• 대한심미치과학회지
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• 제17권1호
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• pp.23-30
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• 2008

Application of CAD/CAM is changing the way partial or full veneer all ceramic restoration is made. CAD/CAM systems, which were used mainly in other industries, have been developed and introduced for the dental purposes recently. It produced a flood of information on the CAD/CAM systems. It also influenced the development of restorative materials and all ceramic is substituting the traditional restorative materials of gold, composite resin and metal. Price increase of gold and other raw materials made the all ceramic more appealing. The introduction of a CEREC 3D system was innovative in several ways. Image of the prepared tooth is captured by camera and impression taking is unnecessary. Restoration can be delivered to the patient on one appointment and it will satisfy the demand of busy patients. One-day treatment with direct CAD/CAM system saves time compared to indirect CAD/CAM system. More superior restoration can be produced if lab work such as the adaptability check and shade selection is cooperated with lab technician. Short working time and comparably superior shade compatibility of color block was close to ideal. In the future, restorations with better quality can be fabricated in less time to busy patients thanks to the development of CAD/CAM system and dental materials.

• 대한치과의사협회지
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• 제50권3호
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• pp.110-117
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• 2012

Dental computer-aided design (CAD) and computer-aided manufacturing (CAM) technology have rapidly progressed over the past 30 years. The technology, which can be used in the dental laboratory, the dental office and the form of production centers, has become more common in recent years. This technology is now applied to inlays, onlays, crowns, fixed partial dentures, removable partial denture frameworks, complete dentures, templates for implant installation, implant abutments, and even maxillofacial prostheses. Dentists and dental technicians, who want to use these techniques, should have certain basic knowledge about that. This article gives an overview of CAD/CAM technologies, histories and how it applies in prosthetic dentistry.