• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.2
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• pp.209-216
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• 1997

A feature is well known as a medium to integrate CAD, CAPP and CAM systems. For a part drawing including both simple geometry and compound geometry, a process plan such as the selection of process, machine tool, cutting tool etc. normally needs simple geometry data and non-geometry data of the feature as the input. However, a extended process plan such as the generation of process sequence, operation sequence, jig & fixture, NC program etc. necessarily needs the compound geometry data as well as the simple geometry data and non-geometry data. In this paper, we propose a feature data model according to the result of analyzing necessary data, including the compound geometry data, the simple geometry data and the non-geometry data. Also, an example of the feature data model in milling process planning is described.

• 한국공간정보시스템학회:학술대회논문집
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• 2000.06a
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• pp.139-153
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• 2000

지리 정보 시스템을 위한 공간 데이터베이스 관리시스템간의 이질성을 최소화하고 공간 데이터의 호환성이나 상호 연동성을 높일 수 있도록 OGC에서 OpenGIS의 사양을 정의하였다. 본 연구에서는 OpenGIS에서 정의된 공간 데이터 모델을 지원하는 컴포넌트를 구현한 것이다. 즉, OpenGIS에서 요구되어진 사양에 따라 SFG (Simple Feature Geometry) 컴포넌트를 구현하였다. 본 논문에서는 컴포넌트 구현상의 발생되었던 문제점과 이 해결 방법을 제시한다. 또한 구현 도중에 발견된 OpenGIS SFG의 사양 자체의 문제점도 함께 제시한다.

• Journal of Korea Spatial Information System Society
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• v.3 no.1 s.5
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• pp.49-62
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• 2001

Recently, component-based software has become main trends in designing and developing computer software products. This component-based software has advantage of the interoperability on distributed computing environment and the reusability of pre-developed components. Also, GIS is designed and implemented with this component-based methodology, called Open GIS Component. OGC(OpenGIS Consortium) have announced various implementation and design specification and topic in GIS. In GIS, Spatial analysis functions like network analysis, TIN analysis are very important function and basically, estimate system functionality and performance using this analysis methods. The simple feature geometry specification is announced by OGC to increase the full interoperability of various spatial data. This specification includes just geometry spatial data model. However, in GIS which manages spatial data, not only geometric data but also topological data and various analysis functions have been used. The performance of GIS depends on how this geometric and topological data is managed well and how various spatial analyses are executed efficiently. So it requires integrated spatial data model between geometry and topology and extended data model of topology for spatial analysis, in case network analysis and TIN analysis in open GIS component. In this paper, we design analysis component like network analysis component and TIN analysis component. To manage topological information for spatial analysis in open GIS component, we design extended data model of simple feature geometry for spatial analysis. In addition to, we design the overall system architecture of open GIS component contained this topology model for spatial analysis.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.04a
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• pp.31-34
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• 2001

지리 정보 자원을 서로 공유하기 위한 표준으로 OGC의 OpenGIS simple feature specification이 있다. Feature의 집합을 다루는 Featurelterator 인터페이스에서 기존의 인터페이스는 서버에 새로운 Feature나 Geometry 객체를 생성하고 클라이언트가 이를 다시 접근 해야하는 비효율성이 존재한다. 그래서 서버에 접근하는 비용을 줄이기 위해, 클라이언트가 서버의 Feature들을 접근하는 방법인, 새로운 get_WKSGeometries 인터페이스를 제안하고 구현한다. 이 인터페이스는 서버에 객체를 생성하는 것이 아니라, WKS 형태로 Feature의 데이터를 클라이언트에 직접 전달함으로써 클라이언트가 서버에 재접근을 요구하지 않는다. 따라서, 이 논문에서 제안한 get_WKSGeometries 인터페이스를 이용하면, 클라이언트가 서버에 접근하는 비용을 줄이고 성능을 향상시키도록 하였다. 아울러 구현 명세를 구현하고 새로운 인터페이스를 제안 검증하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10a
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• pp.154-156
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• 2001

공간정보 및 속성정보를 저장 및 관리하여 서비스하는 지리정보시스템은 최근 네트워크 및 분산환경의 기술개발과 더불어 급격히 변화하고 있다. 이러한 지리 정보시스템은 기존의 패키지, 지역적 클라이언트/서버환경의 기술에서 컴포넌트 기반 기술로 자리메김하고 있는 실정이다. 이러한 컴포넌트 GIS의 기술발전을 위해서 OGC(OpenGIS Consortium)에서는 다양한 설계 및 구현 사양과 토픽을 제시하고 있으며, 대부분의 GIS 기술개발시장에서는 이러한 사양과 토픽에 맞게끔 시스템을 설계 및 구현하고 있다. 지리정보시스템에서 다루는 공간데이터는 크게 기하정보(Geometry)와 위상정보(Topology)로 나뉜다. 지리정보시스템에서 기본석인 질의나 분석에 있어서 기하정보 뿐만 아니라 위상정보도 시스템 전체의 성능에 큰 영향을 미치며, 이러한 위상 정보의 저장, 관리는 필수적이다. 본 논문에서는 개방형 컴포넌트 GIS에서의 기본 기하 데이터 모델인 OGC Simple Feature Geometry 모델과 위상정보 (Topolygy Information)를 나타내는 위상 데이터 모델의 통합 및 연동방법에 대해서 살펴보고, 이러한 데이터모델을 포함하고 있는, OGC 구현사항에 맞게 설계 및 구현된 전체시스템 아키텍쳐를 살펴 볼 것이다.

• Water Engineering Research
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• v.2 no.2
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• pp.75-87
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• 2001

A new moving boundary technique for leap-frog finite difference numerical mode is proposed for the resonable simulation of coastal inundation over discontinuous topography. The new scheme improves the moving boundary technique developed by Imamura(1996). The present scheme is tested using the analytical solution of Thacker(1981) for the case of free oscillation with moving boundary in a parabolic bowl. Finally, a numerical simulation is conducted for the flooding over a tidal barrier constructed on a simple concave geometry. A general feature of inundation over a discontinuous topography is well described by the numerical model.

• Korean Journal of Computational Design and Engineering
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• v.12 no.6
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• pp.413-421
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• 2007

3D rendering is becoming a common feature of mobile application programs with the rapid advance of mobile devices. Since the existing rendering engines do not provide triangulation functions, mobile 3D programs have focused on an efficient handling with pre-tessellated geometry. In addition, triangulation is comparatively expensive in computation, so it seems that the triangulation cannot be easily implemented on mobile devices with limited resources. Triangulation of 3D geometry is the essential process of visualization of 3D model data and many different triangulation methods have been reported. We developed a light and fast visualization process that involves constrained triangulation based on Voronoi diagram and applied it to a mobile computer application. In this paper, we applied kd-tree to the original incremental construction algorithm and produced new O(nlogn) incremental construction algorithm. And we show a simple and efficient constrained triangulation method based on Voronoi diagram. This paper also describes an implementation of mobile STEP data viewer as an application of our proposed algorithms.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.11
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• pp.1080-1087
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• 2009

This paper presents an algorithm to acquire 3D geometric information using a virtual plane method. The method to measure 3D information on the plane is easy, because it's not concerning value on the z-axis. A plane can be made by arbitrary three points in the 3D space, so the algorithm is able to make a number of virtual planes from feature points on the target object. In this case, these geometric relations between the origin of each virtual plane and the origin of the target object coordinates should be expressed as known homogeneous matrices. To include this idea, the algorithm could induce simple matrix formula which is only concerning unknown geometric relation between the origin of target object and the origin of camera coordinates. Therefore, it's more fast and simple than other methods. For achieving the proposed method, a regular pin-hole camera model and a perspective projection matrix which is defined by a geometric relation between each coordinate system is used. In the final part of this paper, we demonstrate the techniques for a variety of applications, including measurements in industrial parts and known patches images.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.12
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• pp.17-23
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• 1997

A 3-D vision system is developed to evaluate blanks' line up and monitor gap and thickness difference between blanks in tailored blank welding system. A structured lighting method is used for 3-D vision recognition. Images of sheared portion in blanks are irregular according to roughness of blank surface, shape of sheared geometry and blurring. It is difficult to get accurate and reliable informations in the case of using binary image processing or contour detection techniques in real time for such images. We propoe a new energy integration method robust to blurring and changes of illumination. The method is computationally simple, and uses feature restoration concept, different to another digital image restoration methods which aim image itself restoration and may be used in conventional applications using structured line lighting technique. Experimental results show this system measuring repeatability is .+-. pixel for gap and thickness difference in static and dynamic tests. The data are expected to be useful for preview gap control.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.3
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• pp.105-115
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• 2015

In semiconductor etching simulation, The source modeling for generating plasma species is required. In this paper, we modeled the source of plasma etching process with probability distribution and the feature profile with simple geometry objects, then got the flux on the feature profile. The distance between the source and the cell on the modeling parameters of the source, there are a number of particles to be emitted from a source, there is a number (area of the cell) of the cell on the profile with additional parameters to give the calculation of flux. The flux error ratio on both gaussian(Incident Flux) and cosine probability distribution(Incident Neutral Flux) is much decreased as the number of ray is increased but the processing time is more increased than that. The increase of the number of cell and distance makes increase the flux error ratio and the processing time moderately. In view of the processing time through the experimental results in this paper, it is possible to analogize the calculation of appropriate fluxes.