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Kim, Eui-Sun;Shim, Kwan-Shik;Moon, Chae-Joo
- Proceedings of the KIEE Conference
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- 2008.07a
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- pp.219-220
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- 2008
이 논문은 이산푸리에변환을 이용하여 시계열데이터에 포함되어 있는 파라미터를 추정하는 새로운 방법과 그 응용 결과를 기술하고 있다. 제안한 방법은 푸리에스펙트럼으로부터 직접 파라미터를 추정하는 방법으로 FFT의 장점을 이용할 수 있으므로 신호에 포함되어 있는 중요 주파수를 비롯한 저주파 진동 파라미터를 빠르게 추정할 수 있다. 이 논문에서는 단순한 산술계산만 수행하여 제동계수를 추정할 수 있도록 알고리즘을 단순화하였다. 그리고 WSCC 계통에서 실측한 데이터에 제안한 알고리즘을 적용하여 효율성을 검증하였다.
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정성수;서상준;조문재;김용태
- Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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- 2003.11a
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- pp.533-536
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- 2003
The Low frequency(1-200 Hz) noise levels radiated by road traffic were investigated. The results showed that the peak pass-by noise of truck with speed of 60km/h was about 75㏈. For the infra-sound frequency range, the noise was about 65㏈ and it was less value than expected. But the noise level will be increase as increasing the speed. The pass-by noise for train was also measured for comparison. The peak train noise was about 95㏈ and it will be enough noise level for a human body to give nuisance.
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Woo, Sangbeom;Lee, Jae-Wan;Ohm, Won-Suk;Kim, Wan-Gu;Kang, Hwi-Suk;Yoon, Suk Wang;Seo, Youngsoo
- Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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- 2014.10a
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- pp.630-634
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- 2014
In this paper, a tile projector was developed for the control of low-frequency underwater echoes. The projector was designed to cover a wide area such as the hull of a submarine, and to have a relatively thin thickness. As a preliminary work for active echo control, the performance of the projector was measured in an anechoic water tank. The transmitting voltage response as well as the passive echo reduction were measured to evaluate the performance as an underwater projector.
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Lee, Jae-Wan;Woo, Sangbeom;Ohm, Won-Suk;Seo, Youngsoo
- Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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- 2014.10a
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- pp.625-629
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- 2014
In this paper, a tile projector for the active control of low-frequency underwater echoes is studied using finite element method. Compared to the existing underwater actuators used for echo reduction, the tile projector is better suited for covering a wide area such as the hull of a submarine. In order to actively match the acoustic impedance at the water-object interface, the projector is driven to radiate a pressure wave that is the inverted replica of the echo at the interface. Finite element simulations demonstrate significant echo reductions due to the active impedance matching by the tile projector.
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Kil Yeong Song;Sae Hyuk Kwon;Kyu Min Ro;Seok Ha Song
- The Transactions of the Korean Institute of Electrical Engineers
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- v.41 no.8
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- pp.841-849
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- 1992
In power system operation, the stability of synchronous machine has been recognized one of the most important things. AESOPS program developed by EPRI in U.S.A. is a frequency domain analysis program in power system stability and it computes the electro-mechanical oscillation mode. This paper presents how to analyze the power system small signal stability problem efficiently by uusing the AESOPS program and analyze the various factors affecting the damping characteristics of these oscillations in KEPCO power system of 1986 with pumped-storage plant. To reduce the computing time and efforts, selecting the poorly-damped oscillation mode and clustering technique have been used. The characteristics of load, the amount of power flow on the transmission line and the gain of exciter have a significant effects on the damping of the system while the governing system has only a minor one. With the Power System Stabilizers, the stability of the power system has been improved.
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