• Journal of Information Technology Application
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• v.1 no.3_4
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• pp.133-152
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• 1999

생산 시스템은 일반적으로 규모가 크고 복잡하며 동시 발생적인 특성을 가지는 경우가 많다. 이러한 특징은 시스템의 행태를 사전에 분석하고 시뮬레이션하기 위한 모델링에 많은 어려움을 가져오게 한다. 본 논문은 이러한 어려움을 해결하기 위하여 객체지향 페트리네트를 이용한 생산시스템 모델링 및 분석 도구를 제사한 것이다. 기본적인 구조는 페트리네트를 객체의 개념으로 구성하는 것이다. 객체의 개념으로 페트리네트를 구성하고 시스템의 행태는 객체간의 메시지 교환과 객체내의 행태로 표현된다. 시스템 분석에 있어서는 객체간의 메시지 전달관계와 객체내의 행태 분석 등이 가능하다. 대상 시스템이 객체의 클래스 개념으로 구성되기 때문에 복잡도가 많이 감소될 수 있다. 특히 본 논문에서는 상속성의 개념을 객체 지향 페트리네트에서 어떻게 구현할 것인가에 대한 방법과 분석 방법이 제시되었다.

• Journal of the Korean Ceramic Society
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• v.55 no.4
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• pp.307-324
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• 2018

Rechargeable lithium-ion batteries (LIBs) have been rapidly expanding from IT based applications to uses in electric vehicles (EVs), smart grids, and energy storage systems (ESSs), all of which require low cost, high energy density and high power density. The increasing demand for LIBs has resulted in increasing price of the lithium source, which is a major obstacle to wider application. To date, the possible depletion of lithium resources has become relevant, giving rise to the interest in Na-ion batteries (NIBs) as promising alternatives to LIBs. A lot of transition metal compounds based on conversion-alloying reaction have been extensively investigated to meet the requirement for the anodes with high energy density and long life-time. In-depth understanding the electrochemical reaction mechanisms for the transition metal compounds makes it promising negative anode for NIBs and provides feasible strategy for low cost and large-scale energy storage system in the near future.

• Proceedings of the KIEE Conference
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• 2001.11b
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• pp.161-163
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• 2001

This paper presents a Case-Sort method to solve the unit commitment problem using database in electric power systems. The formulation of the unit commitment may be described as nonlinear mixed integer programming. However, it is hard to optimize a problem with discrete and continuous variables in a large-scale system at the same time. The Case-Sort method is based on the unit [MW] generation cost considered drive hour. Then, this paper shows effectiveness and economical efficiency of the proposed algorithm.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.101-105
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• 2001

본 논문에서는 한전 전력연구원에서 개발한 전력계통 해석용 시뮬레이터(이하 KEPS)를 이용하여 대규모 전력계통을 실시간으로 해석하는 방법 및 그 결과를 제시하고자 한다. KEPS는 캐나다 RTI사에서 개발한 RTDS(Real-Time Digital Simulator)를 근간으로 하는 대규모 디지털 실시간 시뮬레이터로써 총 26랙으로 구성되어 있으며 대규모 전력계통을 $50{\mu}sec{\sim}70{\mu}sec$의 타임스텝으로 계산할 수 있는 전력계통 전자기 과도현상 모의해석 장치이다. 본 논문에서는 KEPS를 이용하여 한전의 2000년 계통을 실시간으로 해석하고, 전력계통 안정화장치 (PSS), 계전기등 외부기기를 실시간으로 해석, 검증한 결과를 소개하기로 한다.

• Proceedings of the KIEE Conference
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• 1997.07b
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• pp.663-666
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• 1997

This paper presents the development of Distributied Control System for Bookjeju fossil plant. The original analog control system for the power plants has a complex and large-scale structure in their hardware configuration and much difficulties have been experienced for maintenance due to lack of original components. This system connects three different control systems in Bookjeju fossil plant by cue network, The result shows that optimal Distributied Control System has standardization of control system, effective operation management and convenient maintenance of power plant.

• Smart Structures and Systems
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• v.2 no.3
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• pp.275-293
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• 2006

For health monitoring purpose usually the structure is instrumented with a large scale and multichannel measurement system. In case of highway bridges, operating vehicle could be utilized to reduce the number of measuring devices. First this paper presents a static damage detection algorithm of using operating vehicle load. The technique has been validated by finite element simulation and simple laboratory test. Next the paper presents an approach of using this technique to field application. Here operating vehicle load data has been used by instrumenting the bridge at single location. This approach gives an upper hand to other sophisticated global damage detection methods since it has the potential of reducing the measuring points and devices. It also avoids the application of artificial loading and interruption of any traffic flow.

• Journal of the Chungcheong Mathematical Society
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• v.31 no.1
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• pp.137-149
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• 2018

In this paper, under the assumption of the symmetry point spread function, antireflective boundary conditions(AR-BCs) are considered in connection with the fast truncated Lagrange(FTL) method. The FTL method is proposed as an image restoration method for large-scale ill-conditioned BTTB(block Toeplitz with Toeplitz block) and BTHHTB(block Toeplitz-plus-Hankel matrix with Toeplitz-plus-Hankel blocks) linear systems([13, 17]). The implementation and efficiency of the FTL method in the AR-BCs are further illustrated. Especially, by employing the AR-BCs, both the continuity of the image and the continuity of its normal derivative are preserved at the boundary. A reconstructed image with less artifacts at the boundary is obtained as a result.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.10a
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• pp.359-369
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• 1999

The paper describes the study of concurrent subspace optimization(CSSO) for coupled multidisciplinary design optimization (MDO) techniques in mechanical systems. This method is a solution to large scale coupled multidisciplinary system, wherein the original problem is decomposed into a set of smaller, more tractable subproblems. Key elements in CSSO are consisted of global sensitivity equation(GSE), subspace optimization (SSO), optimum sensitivity analysis(OSA), and coordination optimization problem(COP) so as to inquiry valanced design solutions finally, Automatic differentiation has an ability to provide a robust sensitivity solution, and have shown the numerical numerical effectiveness over finite difference schemes wherein the perturbed step size in design variable is required. The present paper will develop the automatic differentiation based concurrent subspace optimization(AD-CSSO) in MDO. An automatic differentiation tool in FORTRAN(ADIFOR) will be employed to evaluate sensitivities. The use of exact function derivatives in GSE, OSA and COP makes Possible to enhance the numerical accuracy during the iterative design process. The paper discusses how much influence on final optimal design compared with traditional all-in-one approach, finite difference based CSSO and AD-CSSO applying coupled design variables.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.170-175
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• 2007

Recently, construction industry in Korea is considering of various approaches for improving productivity and thus enhancing the competitive capacity in the global market. To this end, Korean Ministry of Construction & Transportation has launched R&D project in the field of automation, information systems, high value-added techniques. Furthermore, a new era of cities such as U-city and Eco-city is coming due to the government strategy for developing the country. In the regards of methodological development and trends of construction projects stated above, conventional methods for managing the projects is not likely to guarantee the success. Especially, in the planning and maintenance phases of such large scale cities, a new paradigm should be introduced. We thought of it as 3D object based simulation system for city planning. This paper describes the concept of the system.

• Bulletin of the Korean Space Science Society
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• 2004.10b
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• pp.341-343
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• 2004

In executing the large scale national project, such as development of space launch vehicle, it is most important to guarantee the technological reliability. However the reliability analysis of launch vehicle is different from other mass product goods because of the limitation of budget and number of tests. In this study, the reliability analysis technique of the propulsion system, which is one of the major sub-systems of launch vehicle is illustrated and applied to the liquid rocket engine of KSR-III.