• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.714-718
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• 1997

제품 설계에 있어 설계 기간의 단축과 설계변경에의 효과적인 대응은 매우 중요하다. 본 논문에서는 공학설 계의 한 방법인 구성설계 방법론을 이용하여 제품을 구성하는 부품 사양을 결정하고, 그에 따른 전체 제품의 조림 레이아웃을 파라메트릭 기법을 적용하여 CAD시스템상에 가시화하는 전문가시스템을 구축하였는데,이 시스템은 제품 성계에서 전체적인 품질이 결정되는 초기설계 단계에 대하여 형상 표현에 중점을 두고 구성 되었다.

• 대한기계학회논문집
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• 제17권1호
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• pp.38-45
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• 1993

본 연구에서는 선반작업에서의 피삭체의 형상을 특징형상(feature)단위로 정 의하였고, 이 특징형상을 이용하여 형상정의를 수행한 후 가공순서 및 가공조건을 대 화형식으로 입력하면 공구위치 데이터(CL data)를 자동으로 산출하고 이를 기계제어데 이터(MC data)로 변화시켜 주는 NC선반가공 프로그래밍시스템 FeaTURN (Feature-based TURNing system)을 개발하였다.

• 산업경영시스템학회지
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• 제32권1호
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• pp.102-110
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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. This paper proposes a novel concept, Minus Volume (MV), to incorporate various design information relevant to product lift-cycle functions. MV is a functional shape that is extracted from a design object within a bounding box. A prototype 3D-CAD system is implemented based on the MV concept and illustrated with the successful implementation of concurrent design and manufacturing.

• 한국전자거래학회:학술대회논문집
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• 한국전자거래학회 2001년도 International Conference CALS/EC KOREA
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• pp.615-624
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• 2001

Internet technology opens up another domain for building future CAD/CAM environment. The environment will be global, network-centric, and spatially distributed. In this paper, we present a new approach to network-centric virtual prototyping (NetVP) in a distributed design environment. The presented approach combines the current virtual assembly modeling and analysis technique with distributed computing and communication technology fur supporting virtual prototyping activities over the network. This paper focuses on interoperability, shape representation, and geometric processing for distributed virtual prototyping. STEP standard and CORBA-based interfaces allow the bi-directional communication between the CAD model and virtual prototyping model, which makes it possible to solve the problems of interoperability, heterogeneity of platforms, and data sharing. STEP AP203 and AP214 are utilized as a means of transferring and sharing product models. In addition, Attributed Abstracted B-rep (AAB) is introduced as 3D shape abstraction for transparent and efficient transmission of 3D models and for the maintenance of naming consistency between CAD models and virtual prototyping models over the network.

• 대한기계학회논문집A
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• 제38권10호
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• pp.1075-1084
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• 2014

플랜트 설계를 위해서는 기자재 카탈로그를 구축해야 한다. 기자재의 3 차원 CAD 모델은 목적에 따라 서로 다른 상세도를 가진다. 기자재 제작사는 높은 상세도를 갖는 CAD 데이터를 제공하는 반면에 플랜트 엔지니어링사는 낮은 상세도를 가지는 CAD 데이터가 필요하다. 이와 같은 문제를 해결하기 위해서 기자재 3D CAD 조립체 데이터를 자동으로 간략화하는 시스템을 개발하였다. 이 논문에서는 간략화 시스템의 구조, 상세 기능과 함께 카탈로그 생성을 위한 중립 데이터 형식을 제안한다. 그리고 프로토타입 시스템을 이용한 간략화 실험 결과를 설명한다.

• Journal of Computational Design and Engineering
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• 제1권1호
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• pp.48-54
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• 2014

In this paper, the authors propose a system for assisting mold designers of plastic parts. With a CAD model of a part, the system automatically determines the optimal ejecting direction of the part with minimum undercuts. Since plastic parts are generally very thin, many rib features are placed on the inner side of the part to give sufficient structural strength. Our system extracts the rib features from the CAD model of the part, and determines the possible ejecting directions based on the geometric properties of the features. The system then selects the optimal direction with minimum undercuts. Possible ejecting directions are represented as discrete points on a Gauss map. Our new point distribution method for the Gauss map is based on the concept of the architectural geodesic dome. A hierarchical structure is also introduced in the point distribution, with a higher level "rough" Gauss map with rather sparse point distribution and another lower level "fine" Gauss map with much denser point distribution. A system is implemented and computational experiments are performed. Our system requires less than 10 seconds to determine the optimal ejecting direction of a CAD model with more than 1 million polygons.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.2121-2124
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• 2008

The total length of Korean railway network is about 3,300km. Since it is of great scale in system view point, the systemization of GIS-based information system requires so much cost and time. One of the difficulties is due to the fact that GIS-based information system requires the feature database for GIS, which is generally built manually from many as-built drawing files. In order to build-up the feature database for GIS with ease, this study suggests the automatic data conversion from electronic drawings to make feature database for GIS. The proposed method can be applied to build large-scale railway facility management system at lower cost.

• 한국전자파학회논문지
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• 제30권6호
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• pp.487-497
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• 2019

탄도미사일은 작은 레이다 단면적 및 빠른 기동 특성으로 인하여 탐지가 매우 힘들며, 또한 탄도미사일의 각 비행단계에서 탄두와 유사한 운동 변수로 기동하는 연료탱크 및 기만체의 존재로 인하여 탄두의 식별 및 요격이 매우 어렵다. 따라서 비행 단계에 따라 표적의 기동 및 미세운동을 이용한 특성벡터가 필요하며, 또한 이를 적절히 융합하여 비행단계에 상관없이 식별하는 방법이 요구된다. 본 연구에서는 탄도미사일의 비행단계에 따른 유용한 특성벡터를 소개하고, 이를 특성벡터 및 구분기 레벨에서 융합하는 효과적인 기법을 제안한다. CAD 모델들을 사용하여 예측된 레이다 신호들로 시뮬레이션을 수행한 결과, 구분기 레벨 융합을 통하여 잡음환경 내에서 비행단계에 상관없이 종말 단계로 갈수록 보다 향상된 탄두 식별이 가능하였다.

• Journal of Computational Design and Engineering
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• 제3권2호
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• pp.102-111
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• 2016

In this paper, we study the problem of computing smooth feature curves from CAD type point clouds models. The proposed method reconstructs feature curves from the intersections of developable strip pairs which approximate the regions along both sides of the features. The generation of developable surfaces is based on a linear approximation of the given point cloud through a variational shape approximation approach. A line segment sequencing algorithm is proposed for collecting feature line segments into different feature sequences as well as sequential groups of data points. A developable surface approximation procedure is employed to refine incident approximation planes of data points into developable strips. Some experimental results are included to demonstrate the performance of the proposed method.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2009년도 춘계학술발표대회
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• pp.106-109
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• 2009

Recently, image matching becomes important in Computer Aided Diagnosis (CAD) due to the huge amount of medical images. Specially, texture feature is useful in medical image matching. However, texture features such as co-occurrence matrices can't describe well the spatial distribution of gray levels of the neighborhood pixels. In this paper we propose a frequency domain-based texture feature extractor that describes the local spatial distribution for medical image retrieval. This method is based on 2D Local Discrete Fourier transform of local images. The features are extracted from local Fourier histograms that generated by four Fourier images. Experimental results using 40 classes Brodatz textures and 1 class of Emphysema CT images show that the average accuracy of retrieval is about 93%.