• Nuclear Engineering and Technology
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• 제39권6호
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• pp.717-724
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• 2007

A measurement-based time-domain noise simulation of radiation detector-preamplifier (front-end) noise in nuclear spectroscopy is described. The time-domain noise simulation was performed by generating "noise random numbers" using Monte Carlo's inverse method. The probability of unpredictable noise was derived from the empirical cumulative distribution function via the sampled noise, which was measured from a preamplifier output. Results of the simulated noise were investigated as functions of time, frequency, and statistical domains. Noise behavior was evaluated using the signal wave-shaping function, and was compared with the actual noise. Similarities between the response characteristics of the simulated and the actual preamplifier output noises were found. The simulated noise and the computed nuclear pulse signal were also combined to generate a simulated preamplifier output signal. Such simulated output signals could be used in nuclear spectroscopy to determine energy resolution degradation from front-end noise effect.

• Journal of Mechanical Science and Technology
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• 제18권11호
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• pp.1909-1915
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• 2004

The hermetic rotary compressor is one of the most important components of an air conditioning system since it has a great effect on both the performance and the noise and vibration of the system. Noise and vibration occurs due to gas pulsation during the compression process and to unbalanced dynamic force. In order to reduce noise and vibration, it is necessary to identify their sources and transmission path and effectively control them. Many approaches have been tried in order to identify the noise transmission path of a compressor. However, identification has proven to be difficult since the characteristics of compressor noise are complicated due to the interaction of the compressor parts and gas pulsation. In this study, the statistical energy analysis has been used to trace the energy flow in the compressor and to identify the transmission paths from the noise source to the exterior sound field.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1829-1835
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• 2000

The experimental results of sodium-water reaction noise measurement in frequency range $1{/sim}200kHz$ are presented. The experiments of noise generation under the condition of sodium test facility, water leak rate $0.01{\sim}1.2g/s$ and temperature of sodium $250{\sim}500^{\circ}C$, were carried out. From theoretical study it is noted that the noise resonant attenuation on hydrogen bubbles in liquid sodium plays the significant role for leak noise spectra formation. Interaction of leak noise and hydrogen bubbles in sodium being accompanied by thermal, emission and viscosity energy dissipation was studied. Acoustic noise spectra were investigated from point of view of water leak detection in sodium/water steam generator. The results of sodium-water reaction noise absorption on hydrogen bubbles in liquid sodium by temperature $250{\sim}500^{\circ}C$ are presented. The theoretical model of noise absorption using the coefficients of attenuation was developed. From calculation the coefficients of attenuation were estimated.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2019년도 춘계학술대회
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• pp.236-237
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• 2019

본 논문에서는 웨이블릿 기반의 영상의 노이즈 제거 알고리즘을 제안한다. 기존 Mallat Tree 방식의 웨이블릿 변환을 응용한다. 먼저, 다중 필터링 방법을 제시한다. 웨이블릿 영역에서 각 부대역의 에너지를 고려하여 웨이블릿 변환의 에너지 집중 특성을 극대화 시킨다. 노이즈 영상에 제안한 다중 필터링을 적용한다. 일반 영상에서 나올 수 없는 에너지 부대역을 찾고 이를 제거하여 노이즈를 제거한다.

• 대한전자공학회논문지TC
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• 제48권11호
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• pp.22-27
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• 2011

스펙트럼 감지를 하기 위해 에너지 검파기는 수신 신호의 에너지를 미리 정해둔 임계값과 비교하여 1차 사용자가 면허 대역 내에서 활동을 하는 지 여부를 판단한다. 여기에서 임계값은 해당 주파수 대역에 존재하는 잡음의 전력 수준과 관련이 있다. 에너지 검파에 대한 과거의 연구 대부분은 잡음 전력을 미리 정확하게 알고 있다는 가정에 기초한 것이었다. 그러나 실제 환경에서는 잡음 전력에 대한 불확실성이 존재하기 때문에 이 가정은 현실적으로 유효하지 않다. 그러므로 잡음 전력의 불확실성이 에너지 검파기의 스펙트럼 감지 성능에 미치는 영향을 파악할 필요가 있다. 이에 이 논문에서는 유수 정리(residue theorem)에 기반을 둔 적분을 활용하여 그 영향을 수학적으로 분석하고 그 결과를 제시하고자 한다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 II
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• pp.719-724
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• 2001

The study on reducing vehicle noise and vibration has gained much attention to ensure the comfortability as well as the safety. These days. in this paper, we applied Statistical Energy Analysis(SEA) to characterize the tire assembly, which is useful analytical tool for mid- and high-frequency range. First, the SEA tire model was developed by dividing the tire and the wheel into several subsystems. The material properties were estimated experimentally. Finally. the SEA model was validated by comparing the estimated and the measured. In addition, we investigated the energy level and the energy transfering paths through the tire assembly in different frequency region.

• 대한방사선방어학회:학술대회논문집
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• 대한방사선방어학회 2010년도 춘계 학술발표회 및 심포지엄
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• pp.172-173
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• 2010

• 한국소음진동공학회논문집
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• 제13권1호
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• pp.33-39
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• 2003

Interior parts of a vehicle are getting important to reduce interior noise. Therefore, prior analysis of cabin noise related with interior parts are necessary at first design stage. Recently, Statistical Energy Analysis(SEA) has been suggested as a possible way for high frequency range noise analysis of interior parts. The validity of noise analysis with SEA to interior parts has been preyed by comparing with experimental result, and the developed method with SEA has been applied in finding optimized interior parts package.

• 한국소음진동공학회논문집
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• 제26권4호
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• pp.412-419
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• 2016

The firing noise produced at artillery test range or military training ground is impulsive burst noise which energy is generated within tens of milliseconds and distributed an isolated burst of sound energy separated to one by one noise. The long range propagation of this noise is affected by a caliber of gun, amount of propellant, distance between source and receiver, ground and meteorological condition. In this paper, main influence parameters have been described based on experimental analysis of measured data. It is considered that this analysis result can be used as useful materials for study of effective firing noise management and development of propagation model.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.964-968
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• 2003

Hermetic rotary compressor is one of the most Important components for air conditioning system since it has a great effect on both the performance and the noise and vibration of He system. Noise and vibration of rotary compressor is occurred due to gas pulsation during compression process and unbalanced dynamic force. In order to reduce noise and vibration. it is necessary to identify sources of noise and vibration and effectively control then. Many approaches have been tried to identify noise sources of compressor. However, compressor noise source identification has proven to be difficult since the characteristics of compressor noise are complicated due to the interaction of the compressor parts and gas pulsation. In this work, Statistical Energy Analysis has been used to trace the energy flow in the compressor and identify transmission paths from the noise source to the sound field.