• Journal of KIEE
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• 제11권1호
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• pp.55-61
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• 2001

SIME(Single Machine Equivalent) method has been recognized as a useful tool to determine transient stability of power system. In this paper, SIME method is used to develop the KEPCO transient stability assessment (TSA) tool. A new screening algorithm that can be generators are identified by a new index in the early stage of the time domain simulation. Thus, computational time require to find OMIB(One Machine Infinite Bus) can be reduced significantly. Second, clustering critical machines can be performed even in very stable cases. It enables to be avoid extra calculation of time trajectory that is needed in SIME for classifying the stable cases. This algorithm is applied to the fast TSA of the KEPCO system in the year of 2010.

• 한국지능시스템학회논문지
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• 제16권6호
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• pp.677-682
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• 2006

멀티-도메인 공학시스템은 전기, 기계, 유압, 열등의 구성요소를 포함하고, 시스템 구성이 복잡하여 설계에 많은 어려움을 가지고 있다. 최적의 설계를 위해서는 각 도메인에 대한 통합된 설계 방법과 자동적이고 효율적인 탐색방법이 요구된다. 본 논문은 도메인에 독립적인 모델링 도구인 본드 그래프(Bond Graph)와 대규모 공간 해의 탐색에 접합한 진화 알고리즘의 일종인 유전 프로그래밍(Genetic Programming)를 결합하여 멀티 도메인 동적시스템에 대한 디자인 해를 자동적으로 생성해주는 설계 방법을 제시하였다. 제안된 설계방법의 효용성을 입증하기 위해서 3가지 서로 다른 도메인을 가진 아나로그 필터, 전동프린터 드라이브, 에어펌프 시스템에 대한 설계 결과가 기술된다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.1824-1826
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• 2007

Since standardization project is composed of complicate system, such as vehicle, signal, electric power and railway, how to build management system of the project has influence on the success of the project for the first stage of the project. The computer system design tool supports to carry out requirement analysis, DB construction, and history and follow-up management efficiently. Therefore, the aim of this study is to investigate the method to optimize schema using computer system design tool.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2001년도 춘계학술대회 논문집(한국공작기계학회)
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• pp.275-280
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• 2001

Recently, the trends of industrial products grow more miniaturization, variety and mass production. Micro drilling which take high precision in cutting work is requested more micro hole and high speed working. Especially, Micro deep hole drilling is becoming more important in a wide spectrum of precision production industries, ranging from the production of automotive fuel injection nozzle, watch and camera parts, medical needles, and thick multi-layered Printed Circuit Boards(PCB) that are demanded for very high density electric circuitry. This paper shows the tool monitoring results of micro drill with tool dynamometer. And additionally, microscope with built-in monitor inspection show the relationship between burr in workpiece and chip form of micro drill machining.

• Journal of Mechanical Science and Technology
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• 제16권1호
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• pp.46-59
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• 2002

The main purpose of this study is to investigate the variation of tool electrode edge wear and machining performance outputs, namely, the machining rate (workpiece removal rate), tool wear rate and the relative wear, with the varying machining parameters (pulse time, discharge current and dielectric flushing pressure) in EDM die sinking. The edge wear profiles obtained are modeled by using the circular arcs, exponential and poller functions. The variation of radii of the circular arcs with machining parameters is given. It is observed that the exponential function models the edge wear profiles of the electrodes, very accurately. The variation of exponential model parameters with machining parameters is presented.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 춘계학술대회 논문집
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• pp.457-462
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• 2002

This paper describe the vibration characteristics of cantilevered beam filled with ERF subjected to variousr electrode charge. The Proposed ER fluids used in the present study consists of starch particles and silicon oil. The ER fluids undergo a phase-change when subjected to an external electric filed. This Paper Presents performance analyses of three types of the cantilevered beam with different electrode gaps and applied electric fields.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1998년도 추계학술대회 논문집
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• pp.48-53
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• 1998

In this paper, the new electrochemical machining method is proposed for the micro unit fabrication by using the point electrode tools. The precision shape control capacity is improved by using the point electrode method. It was observed that an electric discharge phenomenon occurs during the electrochemical machining process by using the spraying and torrent type electrolyte supply method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 학술대회 논문집 전문대학교육위원
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• pp.161-165
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• 2002

The paper presents a diagnostic tool for analyzing the bit intermodulation in D/A converter. Bit intermodulation cause linearity errors which degrade the performance of the converter. A linear transformation of the Walsh transform of the integrated non-linearity diagram is shown to be sufficient to extract the bit intermodulation terms and their noise sensitivity. Practical applicability of the proposed method is shown by measurement.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 D
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• pp.1575-1577
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• 1999

XLPE is widely used as a main insulation in EHV power cables, deeply connected with thermal stress. In this study, the thermal history of XLPE insulation was examined using DSC(Differential Scanning Calorimetry). The principle is on the basis of the phenomenon that crystal in polyethylene is rearranged as it is annealed near/below the melting temperature. From the result, it was possible to define accurate temperature which was really applied on the XLPE insulation and this method was assured as a useful tool in characterization of thermal history in XLPE cable insulation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 학술대회 논문집 정보 및 제어부문
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• pp.373-374
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• 2008

To prevent an insulator failure, a new inspection system is presented for 154kV insulator strings. The inspection system detects fault insulators by measuring resistance and voltage of each insulators in the 154kV insulator string. The inspection instrument obtains autonomously insulation resistance and assigned voltage along the insulator string. The insulator inspection instrument is manipulated by two operators. In addition, a set of mechanism is applied to prevent the system from being reset under live-line condition. We confirmed its effectiveness through experiments.