• 한국전자파학회논문지
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• 제8권6호
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• pp.629-635
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• 1997

주기적인 축방향 슬롯이 있는 동축선로 도파관 구조에 TE 편파가 입사될 때 특성모드 이론(characteristic mode theory)을 사용하여 가중 고유방정식(weighted eigenvalue equation)을 유도하고, 일반적인 수치방볍 으로 특성값(characteristic values)과 특성전류(characteristic currents)를 구하여 미지의 등가 자기전류, 산 란패턴과 RCS(radar cross section)를 구하였다. 그리고 이 수치 결과들을 모멘트법을 이용하여 구한 결과들과 각각 비교하여 특성모드에 의한 해석방볍의 타당성을 보였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.79.1-84
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• 1995

The thermal analysis method containing micro drilling characteristic is proposed for the first time. There are such problems in thermal analysis of micro hole drilling as the thermal modeling complexity of drilling process and the undesirable micro drilling characteristic. Especially, the undesirable micro drilling characteristic prevents our using conventional thermal modeling. To model the thermal behavior of the micro drilling process, the finite different method, where heat source vectors are distributed by the measured rhrust and torque, is proposed. This method agrees with thermal behavior of the real system. And, it enable to predict the temperature field near the drill during. The validity of this method is verified in comparing with experimental results.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 신호처리소사이어티 추계학술대회 논문집
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• pp.381-384
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• 2003

Among digital halftoning methods, error diffusion is a procedure for generating high quality bilevel images from continuous-tone images but blurs the edge information in the bilevel images. To solve the problem, we propose the edge enhanced error diffusion using the edge information of the original images. The edge enchanted weights is computed by adding local characteristic weights and input pixels multiplied a constant. Also, we combined the edge enhanced method with the adaptive error diffusion using human spatial and frequency perception characteristic. The performance of the proposed method is compared with conventional method by measuring the edge correlation. The halftoned images applied the proposed method get more fine quality due to the enchanced edge and better quality in halftoned image. And the detailed edge is preserved in the halftoned images by the proposed method.

• 소음진동
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• 제7권5호
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• pp.781-787
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• 1997

A new method is presented to determine two fundamental acoustic quantities of sound-absorbing materials such as characteristic impedance and propagation constant. In this study, the surface acoustic impedances of sound-absorbing materials are measured using the impedance tube and the anechoic chamber to determine the above acoustic quantities. The measured results are given for two typical sound-absorbing materials(glass wool and urethane foam) int the frequency range between 150 and 1, 600 Hz. The results are verified by other two known methods, which are Smith & Parrott method and Utsuno et al. method. The absorption coefficients calculated from the empirical models(Miki model for glass wool and Jung model for urethane foam) and two quantities by present method are in good agreement with the measured values.

• 한국측량학회지
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• 제18권1호
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• pp.67-73
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• 2000

공업화, 도시화가 지속되어 내륙 수계의 수질은 날로 오염되고 있으며, 이와 함께 호수의 수질 또한 악화되어 호수 수질오염 문제는 새로운 수질관리 방안을 필요로 하게 되었다. 본 연구는 GSIS(Geo-Spatial Information System)을 이용한 호수의 수질 관리를 위한 방안의 초기단계로서 GSIS 환경에서 호수의 각종 수리학적 특성 정보를 자동 추출할 수 있는 방안에 대하여 연구하였으며 또한, 추출된 호수의 수리학적 특성정보의 활용의 일례로서 유한차분법을 이용한 호수 수체 흐름의 특성분석을 수행하였다. 수체 흐름의 특성분석에 필요한 각종 수리학적 특성 정보 추출을 GSIS를 이용하여 자동화하므로서 분석작업을 효율적으로 수행할 수 있었으며, 특히 호수단면 정보의 추출을 출력물의 형태가 아닌 다른 정보와 결합하여 분석 가능한 형태로 추출하므로서 호수의 성층현상분석과 같은 호수의 단면정보가 필수적인 각종 분석을 GSIS 환경에서 가능하도록 하였다.

• 한국통신학회논문지
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• 제26권7A호
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• pp.1257-1263
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• 2001

In the paper, the p-ranks and characteristics polynomials of cyclic difference sets are derived by expanding the trace expression of their characteristic sequences. By using this method, it is shown that the 3-ranks and characteristic polynomials of Helleseth-Kumar-Martinsen (HKM) difference set and Lin difference set can be easily obtained.

• 대한전기학회논문지
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• 제32권11호
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• pp.387-393
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• 1983

This paper descrives the computational algorithm for determination of system characteristic constants using diakoptic method. When the system charateristic contants of large scale power system are calculated by using sensitivity matrix method which requires the inversion of Jacobian matrix, the necessary computing time and memory requirements increase very largely. Diakoptic mothods is benefit to get around these problems, and it is applied to a model system compared with the integrated method to discuss the efficiency of the algorithm.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(1)
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• pp.137-140
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• 2003

Shorted-turns can have significant effects on a generator and its performance. Shorted-turn sensor for synchronous generator's field winding have been developed. One of effective method detecting inter-turn short circuits on round rotor winding is a method using sensor detecting. But the method needs duplicate design of sensor for characteristic change according to types and forms of generator Thus sensing skill without sensor depend on change of electric property in generator. For the reason, this paper presents shorted-turns phenomenon and the characteristic analysis of shorted-turns In synchronous generator by using 2-D finite element method(FEM).

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -1
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• pp.42-45
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• 2002

A novel characteristic value extraction method based on morphological spatial frequency is proposed. Morphological spatial frequency defined by morphological pattern distribution function is introduced. Superiority of the method was proved for various images by experiment. Furthermore the fact that the proposed method does not need threshold to obtain binary image provides its applicability to content-based image retrieval.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제51권7호
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• pp.379-386
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• 2002

This paper deals with dynamic analysis method of a slotless type permanent magnet linear synchronous motor(PMLSM) using 3-dimensional space harmonic method. The results are good agreement with FEA results because that slotless type PMLSM has simple structure and no saturation of core. And then, Under open-loop control, starting characteristic is analyzed by voltage equation combining with dynamic equation. In order to obtain more accuracy results, this paper use instantaneous back-EMF and thrust instead of back-EMF constant and thrust constant.