• Proceedings of the Computational Structural Engineering Institute Conference
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• 1995.10a
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• pp.43-49
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• 1995

Sasol Advanced Synthol Reactor was divided into two chambers by grid plate perforated with diffuser holes. The reactor has high stress level beacuse of membrane stress due to internal pressure, thermal stress due to temperature difference and local stress due to structural discontinuity at the juncture of grid plate and shell. Moreover, geometric nonlinear behaviors may appear in the grid plate because of pressure difference between two chambers. In order to survey the stress level and geometric nonlinear behaviors around grid plate, heat transfer analysis, linear static analysis and geometric nonlinear analysis were performed using NISA II developed by EMRC. This paper demonstrates the result of accessment for linear static and geometric nonlinear analysis under various load combinations.

• Computational Structural Engineering : An International Journal
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• v.3 no.1
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• pp.19-29
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• 2003

In the present study, finite element linear buckling analysis is performed for grid-stiffened composite plates. A hybrid element with drilling degrees of freedom is employed to reduce the effect of the sensitivity of mesh distortion and to match the degrees of freedom between skins and stiffeners. The preliminary static stress distribution is analyzed for the determination of accurate load distribution. Parametric study of grid structures is performed and three types of buckling modes are observed. The maximum limit of buckling load was found at the local skin-buckling mode. In order to maximize buckling loads, stiffened panels need to be designed to be buckled in skin-buckling mode.

• Journal of radiological science and technology
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• v.40 no.4
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• pp.575-580
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• 2017

Because moire artifacts overlap with fine lesions and frequency bands, image processing software that removes moire artifacts can lead to loss of micro lesions. In this study, microscopic lesions such as microcalcification and microfracture were randomly formed on SD (Sprague Dawley) rats and image and optimized grid images were compared and analyzed using reference image and grid suppression software. The images were read by two consecutive radiologists using a McNemar's test. Among the 73 microcalcifications, in the 13 cases after grid suppression, the image of the optimized grid shows the loss of image in 3 cases, and the image after grid suppression shows statistically significant image loss (p=0.021). In all 53 fracture lines, there were 19 cases of image loss after the grid suppression, and only one case of the optimized grid showed no image loss. Therefore, the use of grid suppression software to remove moire artifacts should be carefully considered in the diagnosis of micro lesions.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.543-544
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• 2007

Micro-grid consists of micro-sources which adopt environmentally friendly and reliable power sources with independent real and reactive power control capability for providing premium power quality. This paper presents dynamic modeling and the stable operating range of the micro-grid system varying the parameters of the micro-sources. Case study results show the parameters affecting the stability of the micro-grid and the stable operating range of the micro-sources.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.12
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• pp.37-42
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• 2007

Clock grid networks are now common in most high performance microprocessors. This paper presents a new effective modeling and simulation methodology for the clock grid using scattering parameter. It also shows the effect of wire width and grid size on the clock skew of the grid. The interconnection of the clock grid is modeled by RC passive elements. The results show that the error is within 10 % comparing to Hspice simulation results.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.66-69
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• 2002

This article outlines the capabilities of a viewer component called GridViewer, and proves its reusability. GridViewer was designed for the construction of the image display part of GIS or remote sensing application software, and consequently it is particularly straightforward to closely couple GridViewer with access to very large images. Displaying is performed through pyramid structure, which enables to treat very large dataset up to several gigabytes in size under the limited capability of PC. GridViewer is free from responsibility to handle various formats of raster data files by taking grid coverage, which is designed by OGC to promote interoperability between implementations done by data vendors and software vendors providing analysis and grid processing implementations. GridViewer differs from other such viewer by allowing for clients to extend its function and capability by using small set of methods originally implemented in it. We show its reusability and expandability by applying it in developing application programs performing various functions not supported originally by the GridViewer COM component.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1989-1990
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• 2011

스마트그리드 즉, 미래 지능형 전력시스템이 추구하는 가장 큰 특징은 표준화 기반의 시스템간 상호운용성과 최신 기술을 이용한 자동화라고 할 수 있겠다. 그러므로 시스템간 상호 운용이 가능한 스마트그리드 시스템의 개발을 위해서는 요구분석부터 전반적인 시스템의 조건을 만족할 수 있도록 고려되어야 한다. 스마트그리드를 위한 전력시스템의 개발에 활용 될 수 있는 방법론으로는 'IEC 62559 IntelliGrid Methodology(IntelliGrid$^{SM}$, 이하 IntelliGrid 방법론)'이 있다. IntelliGrid 방법론은 IEC에 의하여 2007년에 채택된 전력에너지시스템 개발을 위한 방법론(IEC 62559, PAS(Publicly Available Specification))으로, EPRI의 'IntelliGrid 프로그램'의 산출물이다. IntelliGrid 방법론에 기반한 요구분석 방법론을 체계적인 스마트그리드 시스템 개발을 위한 요구분석 방안을 제시한 결과물로 평가할 수 있다. 본 논문에서는 IntelliGrid 방법론의 내용을 분석해 보고, AMI 개발을 위한 요구분석 방법론으로 'IntelliGrid 방법론'을 적용하는 방안 및 절차에 관하여 제시하고자 한다.

• Journal of computational fluids engineering
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• v.12 no.3
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• pp.20-28
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• 2007

A fast and robust method of grid generation to multiple functions has been developed for flow analysis in three dimensional space. It is based on the Non-Uniform Rational B-Spline(NURBS) of an approximation method. Many of NURBS intrinsic properties are introduced and much more easily understood. The grid generation method, details of numerical implementation. examples of application, and potential extensions of the current method are illustrated in this paper. The object of this study is to develop the surface grid generation and the grid cluster techniques capable of resolving complex flows with shock waves, expansion waves, shear layers. The knot insert method of Non-Uniform Rational B-Spline seems well worked. In addition, NURBS has been widely utilized to generate grids in the computational fluid dynamics community. Computational examples associated with practical configurations have shown the utilization of the algorithm.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.5
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• pp.841-847
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• 2007

This paper deals with the micro-grid consisting of micro-sources which adopt voltage sourced inverters with independent real and reactive power control capability for providing premium power quality. This paper presents dynamic modeling and the stable operating range of the micro-grid system varying the parameters of the micro-sources. The fundamental frequency model of the micro-source inverters are considered to form a dynamic model of the micro-grid system. Stability analysis is performed based on the linearized dynamic model of the micro-grid system. Case study results show the parameters affecting the stability of the micro-grid and the stable operating range of the micro-sources.

• Proceedings of the Korean Society of Computer Information Conference
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• 2011.06a
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• pp.75-77
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• 2011

Smart Grid는 전기망과 정보통신망이 융합된 형태로 발전 송전 배전의 전 과정에 대한 통제가 가능하고, 결과적으로 에너지 사용의 효율성을 높이고자 하는 것이 지능형 전기망이다. 정보통신망을 이용하기 때문에 기존의 다양한 사이버 보안위협으로부터 그대로 노출되어 있으며, 전기망에서의 취약점도 함께 가지고 있다. 본 논문에서는 우리나라보다 먼저 Smart Grid를 도입한 나라의 Smart Grid 공격 사례와 예상 공격에 대한 취약점을 분석하고, 분석된 취약점에 대한 Smart Grid 보안 대책을 마련한다. 본 연구를 통해 Smart Grid에 대한 보안성 강화와 사회안정성 향상에 기여하게 될 것이다.