• 제목/요약/키워드: Computer-aided Research

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네트워크 분산 환경 하에서 설계대상물의 외부공간을 이용한 3차원 CAD 시스템에 의한 협조설계 지원 (Collaborative Design based on 3D-CAD System Using Functional Space Surrounding Design Object over the Networked Environment)

  • 남윤의;석천청웅
    • 산업경영시스템학회지
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    • 제32권4호
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    • pp.169-177
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    • 2009
  • Concurrent Engineering (CE) has presented new possibilities for successful product development by incorporating various product life-cycle functions from the earlier stage of design. In the product design, geometric representation is vital not only in its traditional role as a means of communicating design information but also in its role as a means of externalizing designer's thought process by visualizing the design product. During the last dozens of years, there has been extraordinary development of computer-aided tools intended to generate, present or communicate 3D models. However, there has not been comparable progress in the development of 3D-CAD systems intended to represent and manipulate a variety of product life-cycle information in a consistent manner. In the previous research, the authors proposed a novel concept called Minus Volume (MV) to incorporate various design information relevant to product life-cycle functions. This paper proposes the use of the MV concept for the collaborative design environment, where many team members are geographically distributed over the networked environment, including Internet, Intranet, WWW, etc. A prototype 3D-CAD system is implemented based on the MV concept and illustrated with the successful implementation of collaborative design example.

전산 선형설계 시스템의 개발을 위한 기준모델 (A Reference Model for the Computer-Aided Design of Hull Forms)

  • 한순흥;이순섭
    • 대한조선학회논문집
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    • 제31권4호
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    • pp.15-22
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    • 1994
  • 컴퓨터를 이용하여 선박의 선형설계 작업을 개선하고자 하는 노력은 컴퓨터가 개발되어 이용되기 시작한 1960대부터이다. 우리나라에서도 FORAN 등의 도입된 소프트웨어를 통해 일찍부터 관심을 가졌으나, 자체 개발을 위한 활동은 최근에야 활발해지고 있다. 선형설계 시스템의 개발에 제한된 개발자원을 효율적으로 이용하기 위해서는 업무의 분담과 통합을 위한 공통의 개발모델이 필요하다. 이 글에서는 국내외의 관련연구, 특히 조선 이외 분야의 연구를 포함하여, 기술개발 현황을 분석하고, 이를 바탕으로 전산 선형설계 시스템의 개발을 위한 하나의 기준모델을 제시하였다. 이 과정에 전산선형설계를 구성하는 요소기능들이 새롭게 분류되었으며, 이들 간의 조합을 통해 기준모델을 구성하였다.

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치과용 지르코니아로 제작된 심미보철물의 임상적 예후에 관한 문헌고찰 (Review of clinical studies applying yttrium tetragonal zirconia polycrystal-based esthetic dental restoration)

  • 김재홍
    • 대한치과기공학회지
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    • 제42권4호
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    • pp.307-312
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    • 2020
  • Application of ceramic materials for fabrication of dental restoration materials has been a focus of interest in the field of esthetic dentistry. The ceramic materials of choice are glass ceramics, spinel, alumina, and zirconia. The development of yttrium tetragonal zirconia polycrystal (YTZP)-based systems is a recent addition to all-ceramic systems that have high strength and are used for crowns and fixed partial dentures. Computer-aided design/computer-aided manufacturing (CAD/CAM)-produced, YTZP-based systems are popular with respect to their esthetic appeal for use in stress-bearing regions. The highly esthetic nature of zirconia and its superior physical properties and biocompatibility have enabled the development of restorative systems that meet the demands of today's patients. Many in vitro trials have been performed on the use of zirconia; however, relatively fewer long-term clinical studies have been published on this subject. The use of zirconia frameworks for long-span fixed partial dentures is currently being evaluated; in the future, more in vivo research and long-term clinical studies are required to provide scientific evidence for drawing solid guidelines. Further clinical and in vitro studies are required to obtain data regarding the long-term clinical use of zirconia-based restorations.

Production automation system for three-dimensional template pieces used to evaluate shell plate completeness

  • Son, Seunghyeok;Kim, Byeongseop;Ryu, Cheolho;Hwang, Inhyuck;Jung, ChangHwan;Shin, Jong-Gye
    • International Journal of Naval Architecture and Ocean Engineering
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    • 제12권1호
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    • pp.116-128
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    • 2020
  • In the shipbuilding industry, three-dimensional (3D) templates play a key role in the completeness evaluation of shell plates with a large curvature in the shell-plate fabrication process. Currently, the information of 3D templates from a ship computer-aided design system is limited; thus, manufacturers depend on their experience to produce the templates manually. This results in the inaccuracy of templates in addition to increased production time. Therefore, if the pieces of the 3D templates can be produced automatically with accurate information, the lead time of the fabrication process can be reduced. In this study, we define a new type of template piece and develop methods for extending a boundary template and converting manufacturing information into numerical control machine input. In addition, based on the results of the study, we propose a production automation system for 3D template pieces. This system is expected to reduce the lead time of the fabrication process.

Artificial Intelligence-Based Breast Nodule Segmentation Using Multi-Scale Images and Convolutional Network

  • Quoc Tuan Hoang;Xuan Hien Pham;Anh Vu Le;Trung Thanh Bui
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제17권3호
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    • pp.678-700
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    • 2023
  • Diagnosing breast diseases using ultrasound (US) images remains challenging because it is time-consuming and requires expert radiologist knowledge. As a result, the diagnostic performance is significantly biased. To assist radiologists in this process, computer-aided diagnosis (CAD) systems have been developed and used in practice. This type of system is used not only to assist radiologists in examining breast ultrasound images (BUS) but also to ensure the effectiveness of the diagnostic process. In this study, we propose a new approach for breast lesion localization and segmentation using a multi-scale pyramid of the ultrasound image of a breast organ and a convolutional semantic segmentation network. Unlike previous studies that used only a deep detection/segmentation neural network on a single breast ultrasound image, we propose to use multiple images generated from an input image at different scales for the localization and segmentation process. By combining the localization/segmentation results obtained from the input image at different scales, the system performance was enhanced compared with that of the previous studies. The experimental results with two public datasets confirmed the effectiveness of the proposed approach by producing superior localization/segmentation results compared with those obtained in previous studies.

유방촬영술에서 인공지능의 적용: 알고리즘 개발 및 평가 관점 (Applications of Artificial Intelligence in Mammography from a Development and Validation Perspective)

  • 김기환;이상협
    • 대한영상의학회지
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    • 제82권1호
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    • pp.12-28
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    • 2021
  • 유방촬영술은 유방암 검진 및 진단을 위한 기본적인 영상 검사이지만, 판독이 어려우며 높은 숙련도를 필요로 한다고 잘 알려져 있다. 이러한 어려움을 극복하기 위해 최근 몇 년 사이에 인공지능을 이용한 유방암 검출 알고리즘들이 활발히 연구되고 있다. 본 종설에서 저자는 고전적인 computer-aided detection 소프트웨어 대비 최근 많이 사용되는 딥러닝의 특징을 알아보고, 딥러닝 알고리즘의 개발 방법과 임상적 검증 방법에 대해서 기술하였다. 또한 딥러닝 기반의 검진 유방촬영술의 판독 방법 분류, 유방 치밀도 평가, 그리고 유방암 위험도 예측 모델 등을 위한 딥러닝 연구들도 소개하였다. 마지막으로 유방촬영술 관련 인공지능 기술들에 대한 영상의학과 전문의의 관심과 의견의 필요성을 기술하였다.

Comparative fracture strength analysis of Lava and Digident CAD/CAM zirconia ceramic crowns

  • Kwon, Taek-Ka;Pak, Hyun-Soon;Yang, Jae-Ho;Han, Jung-Suk;Lee, Jai-Bong;Kim, Sung-Hun;Yeo, In-Sung
    • The Journal of Advanced Prosthodontics
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    • 제5권2호
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    • pp.92-97
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    • 2013
  • PURPOSE. All-ceramic crowns are subject to fracture during function. To minimize this common clinical complication, zirconium oxide has been used as the framework for all-ceramic crowns. The aim of this study was to compare the fracture strengths of two computer-aided design/computer-aided manufacturing (CAD/CAM) zirconia crown systems: Lava and Digident. MATERIALS AND METHODS. Twenty Lava CAD/CAM zirconia crowns and twenty Digident CAD/CAM zirconia crowns were fabricated. A metal die was also duplicated from the original prepared tooth for fracture testing. A universal testing machine was used to determine the fracture strength of the crowns. RESULTS. The mean fracture strengths were as follows: $54.9{\pm}15.6$ N for the Lava CAD/CAM zirconia crowns and $87.0{\pm}16.0$ N for the Digident CAD/CAM zirconia crowns. The difference between the mean fracture strengths of the Lava and Digident crowns was statistically significant (P<.001). Lava CAD/CAM zirconia crowns showed a complete fracture of both the veneering porcelain and the core whereas the Digident CAD/CAM zirconia crowns showed fracture only of the veneering porcelain. CONCLUSION. The fracture strengths of CAD/CAM zirconia crowns differ depending on the compatibility of the core material and the veneering porcelain.

컴퓨터 시뮬레이션(CAE)을 이용한 자동차용 AA6061 리어 서브-프레임 사이드멤버의 하이드로-포밍 공정 개발 (Hydro-forming Process Development of Automotive AA6061 Rear Sub-frame Side Member by Computer Aided Engineering (CAE))

  • 김기주;김재현;최병익
    • 한국자동차공학회논문집
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    • 제18권5호
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    • pp.45-49
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    • 2010
  • The automotive industry has shown a growing interest in tube hydroforming during the past years. The advantages of hydroforming (less thinning, a more efficient manufacturing process, etc.) can, for instance, be combined with the high strength of extra high strength steels, which are usually less formable, to produce structural automotive components which exhibit lower weight and improved service performance. Design and production of tubular components require knowledge about tube material and forming behavior during hydroforming and how the hydroforming operation itself should be controlled. These issues are studied analytically in the present paper. In this study, the whole process of rear sub-frame parts development by tube hydroforming using AA6061 material is presented. At the part design stage, it requires feasibility study and process design aided by CAE (Computer Aided Engineering) to confirm hydroformability in details. Effects of parameters such as internal pressure, axial feeding and geometry shape in automotive rear sub-frame by hydroforming process were carefully investigated. Overall possibility of hydroformable rear sub-frame parts could be examined by cross sectional analyses. Moreover, it is essential to ensure the formability of tube material on every forming step such as pre-bending and hydroforming. In addition, all the components of prototyping tool are designed and interference with press is examined from the point of geometry and thinning.

SELECTION OF DAMPING MODEL IN VIBRATION OF FLEXIBLE BEAMS

  • Kim, Hyun-Woo;Yoo, Wan-Suk
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2007년도 춘계학술대회A
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    • pp.578-583
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    • 2007
  • Many papers have studied computer-aided simulations of elastic bodies undergoing large deflections and large deformations. But there have been few attempts to validate their numerical formulations used in these studies. The main aim of this paper is to validate the absolute nodal coordinate formulation (ANCF) by comparing the results to experimental measurements on beams. Physical experiments with a high-speed camera were carried out to capture the large displacement of the beam and to verify the results of computer simulations. To consider the damping forces, the Rayleigh's damping and quadratic damping are employed and compared to the experimental results, respectively. Numerical results obtained from computer simulations were compared with the results from the physical experiments according to the $1^{st}$ mode and the $2^{nd}$ mode of the beam, respectively.

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Marginal fit of anterior 3-unit fixed partial zirconia restorations using different CAD/CAM systems

  • Song, Tae-Jin;Kwon, Taek-Ka;Yang, Jae-Ho;Han, Jung-Suk;Lee, Jai-Bong;Kim, Sung-Hun;Yeo, In-Sung
    • The Journal of Advanced Prosthodontics
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    • 제5권3호
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    • pp.219-225
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    • 2013
  • PURPOSE. Few studies have investigated the marginal accuracy of 3-unit zirconia fixed partial dentures (FPDs) fabricated by computer-aided design/computer-aided manufacturing (CAD/CAM) system. The purpose of this study was to compare the marginal fit of zirconia FPDs made using two CAD/CAM systems with that of metal-ceramic FPDs. MATERIALS AND METHODS. Artificial resin maxillary central and lateral incisors were prepared for 3-unit FPDs and fixed in yellow stone. This model was duplicated to epoxy resin die. On the resin die, 15 three-unit FPDs were fabricated per group (45 in total): Group A, zirconia 3-unit FPDs made with the Everest system; Group B, zirconia 3-unit FPDs made with the Lava system; and Group C, metal-ceramic 3-unit FPDs. They were cemented to resin dies with resin cement. After removal of pontic, each retainer was separated and observed under a microscope (Presize 440C). Marginal gaps of experimental groups were analyzed using one-way ANOVA and Duncan test. RESULTS. Mean marginal gaps of 3-unit FPDs were $60.46{\mu}m$ for the Everest group, $78.71{\mu}m$ for the Lava group, and $81.32{\mu}m$ for the metal-ceramic group. The Everest group demonstrated significantly smaller marginal gap than the Lava and the metal-ceramic groups (P<.05). The marginal gap did not significantly differ between the Lava and the metal-ceramic groups (P>.05). CONCLUSION. The marginal gaps of anterior 3-unit zirconia FPD differed according to CAD/CAM systems, but still fell within clinically acceptable ranges compared with conventional metal-ceramic restoration.