• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.127-131
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• 2007

A laboratory study on low frequency noise assessment was carried out to determine the acceptability limits in the frequency range between 20 and 200 Hz. The acceptability limits were tested in the anechoic chamber to minimize the background noise. A total of 30 test subjects, who were aged between 19 to 33 years, participated in this study. They were exposed to various stimuli for about 1 hour by supra-aural earphone. The experiment consisted of two listening sessions; hearing threshold and the acceptability limits session. The results showed that the trend of the acceptability limits curve was approximately equal to C-weighting curve which had been found to be superior to A-weighting curve in low frequency noise assessment.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 추계학술대회논문집
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• pp.596-599
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• 2008

Traditionally, tire made a role of function, which is supporting vehicle load, making brake, transferring traction, etc. But tire is a part of vehicle design, nowadays. In accordance with this market trend, customers need a wide tread design tire (i.e. low series tire). Generally low Series Tire means stiffer than general tire. That brings out increasing road noise. (Especially tire cavity resonance noise) Tire noise is divided in structure home noise and air borne noise. Tire cavity resonance noise (structure home noise) come from vibration between tire and vehicle. In the study, we investigated that tire cavity resonance noise is affected by stiffness of tread and sidewall.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.1048-1052
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• 2007

Using road traffic noise, noise map for CheongJu city was drawn. Noise level is estimated and many regions of the city are classified noise excess area compared with environment standard value. Counterplan for the noise excess areas is presented in this study. Noise reduction methods are given in many ways, for example soundproofing walls, low noise pavement, low noise arrangement of buildings and low noise windows.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.187-192
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• 2006

Helicopter noise has been considered as one of major design factors like a performance and safety since the public acceptance, comfortability and stealth aspects were important for customers. According to the airworthiness regulation, the noise levels in throe different flight conditions shall comply with the specific limits. Main and tail rotors noise is most dominant in far field due to the low and mid range frequency characteristics. It is an air-born noise so That the accurate aerodynamic data is necessary for the accurate noise prediction. In KARI, low noise main and tail rotors as well as analysis codes have been developed since 2000. The approach for low noise main rotor is a kind of tip modifications, so called twin vortices tip to reduce the BVI noise. Analysis results show the 9.3dB reduction in terms of pseudo EPNL. The uneven spacing concept is applied for low noise tail rotor. Three or four decibel noise reduction is achieved by new optimized uneven spacing. Rotor noise and aerodynamic prediction codes have been improved also.

• 전자공학회논문지
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• 제54권2호
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• pp.53-57
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• 2017

본 논문에서는 의료 기기용 401MHz - 406MHz MedRadio 대역에서 사용하는 저잡음 증폭기를 제안한다. 제안한 저잡음 증폭기는 전류 재사용 gm-boosting 기술을 이용한 공통 게이트 증폭기 구조를 채택하여 기존의 gm-boosted 공통 게이트 증폭기에 비해 동일한 전력소모에서 더 높은 전압 이득과 더 낮은 잡음 지수 특성을 얻었다. 제안한 전류 재사용 gm-boosted 저잡음 증폭기는 $0.13{\mu}m$ CMOS 공정을 사용하여 설계하였고, 22 dB의 전압 이득, 2.95 dB의 잡음 지수, -17 dBm의 IIP3 특성을 보이며, 공급 전압 0.5 V에서 $170{\mu}W$의 전력을 소비한다.

• 한국항공운항학회지
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• 제31권4호
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• pp.116-125
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• 2023

Gimpo International Airport is a strategically utilized airport based on government policy, but there are many residents living around the airport, so it is very sensitive to changes in airport operation. In the past, similar noise results were obtained for aircraft noise at Gimpo International Airport despite changes in aircraft types and an increase in the number of aircraft operating, and recently ICAO proposed a low-noise aircraft noise standard (Ch.14). Since the new standard has a noise reduction effect of up to 15dB compared to existing aircraft noise, ICAO and Europe EASA predict that future aircraft noise will be reduced if the latest technologies such as low-noise aircraft are applied. Therefore, this study establishes the aircraft operation performance and measured noise of Gimpo International Airport in 2022 as a baseline scenario, noise changes using various scenarios of introduction of low-noise aircraft, operation of mid-to-long-distance routes, and changes in future air traffic demand were analyzed using simulation.

• 조명전기설비학회논문지
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• 제23권8호
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• pp.110-115
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• 2009

최근 생활수준의 향상과 세계적인 녹색성장 정책으로 환경에 대한 관심이 고조되어, 전력분야에서도 환경친화적인 설비가 요구되어 지고 있다. 이에 따라 전력용 변압기 냉각팬도 날개형상과 배치형태를 개선한 저소음 냉각팬이 개발되었으며, 일반 전력용 변압기 및 저소음 변압기에 적용될 예정이다. 냉각팬은 낮은 소음레벨 뿐만 아니라 우수한 냉각성능의 확보가 필수적이다. 그러나 현재까지 저소음 냉각팬의 소음레벨과 냉각성능에 대한 검토가 이루어지지 않은 실정이다. 따라서 본 논문에서는 소음레벨 측정과 풍량 측정 실험을 통해 저소음 냉각팬의 성능을 분석하였다. 또한 저소음 냉각팬을 적용한 전력용 변압기의 온도상승 시험을 통하여 냉각성능을 검증하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.857-862
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• 2002

Compressor is a major noise source of air-conditioner. Especially, its low frequency band noise below 1000Hz is very important because it will not be attenuated by passing through the cover panel and heat exchanger in air-conditioner. The factors affecting the low frequency band noise are studied by geometric similarity along with several experiments, and the low frequency noise is closely related with the discharge holes of muffler as well as the cavity of lower shell. The low frequency band noise is significantly reduced by proposed designs.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 추계학술대회논문집
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• pp.483-488
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• 2008

The exhaust system, including a muffler, is one of the major sources to generate the radiated noise of construction equipment. In general, the muffler is applied to construction equipment in order to reduce the exhaust noise. Sometimes, however, the higher exhaust noise can be experienced due to the flow effect inside a muffler. So, it is required to consider the flow effect to reduce the exhaust noise level of construction equipment. In this paper, various tests were performed to calculate the flow noise effect inside a muffler. Through a series of tests with respect to a variety of design parameters, a new design program for low noise muffler was developed and applied to reduce the exhaust noise of the construction equipments. These results make it possible to understand the dynamic characteristics of the flow noise and to design the low noise muffler for the construction equipments.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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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.