• 한국소음진동공학회논문집
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• 제23권12호
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• pp.1056-1065
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• 2013

Noise generated from Construction site has been raised most civil complaints to 64.4 % among the environmental pollution in 2011. Therefore, local government recommends and prescribes that construction sites over a certain scale install sound level meter for noise monitoring. For example, Seoul has implemented a 24 hour noise monitoring system, with real time communication, to the large construction sites more than 10,000 $m^2$ from the end of August 2012. But it is difficult to use noise measurement data for the construction noise assessment, since the installation standards and technical specifications for construction noise monitoring system are not presented. In this paper, we proposed noise monitoring system improvement plan including technical specifications and installation standards using the investigating results of the problems of current noise monitoring system and the foreign cases.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.527-532
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• 2014

Generator is the main equipment of a power plant that generates electric power. The line frequency is 60Hz, since that is operated at 3600rpm in fossil power plant. Therefore, the specific frequency 120Hz by the electromagnetic excitation force is generated inherently. If the looseness of stator at generator happens, abnormal sound that has 120Hz and the harmonic frequency is emitted from generator frame. In that case, binding of end-winding or re-wedging is needed for the reduction of sound level. In case of severe level of sound, belly band can be additionally installed at core. In this paper, the characteristics of generator sound is described and modal data is analyzed after installation of belly band.

• Advances in aircraft and spacecraft science
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• 제3권3호
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• pp.259-269
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• 2016

In this work results from an underwater experiment on flow-induced noise in the interior of a towed body generated from a surrounding turbulent boundary layer are presented. The measurements were performed with a towed body under open sea conditions at towing depths below 100 m and towing speeds ranging from 2.4 m/s to 6.2 m/s (4 kn to 12 kn). Focus is given in the experiments to the relation between (outer) wall pressure fluctuations and the (inner) hydroacoustic near-field on the reverse side of a flat plate. The plate configuration consists of a sandwich structure with an (thick) outer polyurethane layer supported by an inner thin layer from fibre-reinforced plastics. Parameters of the turbulent boundary layer are estimated in order to analyse scaling relations of wall-pressure fluctuations, interior hydroacoustic noise, and the reduction of pressure fluctuations through the plate.

• 한국지리정보학회지
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• 제24권4호
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• pp.174-183
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• 2021

본 연구는 아마존 AWS를 이용해 클라우드 컴퓨팅 기반의 실시간 환경소음 지도를 제공하는 방법 제시를 목적으로 한다. 우선, 환경 소음정보를 취득하기 위해 안드로이드 앱을 개발하여 인하공업전문대학 캠퍼스의 소음레벨, 위치, 측정시간에 데이터를 수집하였다. 소음 측정정보는 AWS 클라우드로 전송되어 관리되며, 아마존 퀵사이트를 통해 수집된 소음정보를 차트와 지도로 시각화 하였다. 마지막으로 환경 소음분포 현황을 사용자들이 검색하기 위해 웹 기반 소음 등고선도와 건물에 매핑된 결과를 구글 지도로 제공하였다. 본 연구에서 제시된 소음지도는 실시간 데이터로 제작되어 소음 현황과 저감 대책 마련에 도움을 줄 수 있을 것이라고 판단된다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.482-485
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• 2004

On the basis of theoretical studies on the effect of the cylinders attached to semi-infinite screens, the tangential sound power-transport parallel to the surface of the attached cylinder is minimized by means of a secondary sound field, which is generated from a part of the attached cylinder. The numerical study shows the possibility of deflecting the incident sound by minimizing the acoustic surface impedance of the upper sections. The acoustical shadow region was more pronounced in both near- and far-field compared to the passive case with rigid surface, i.e. without active control. For a relatively wide frequency range it was possible to enhance shielding effects only with few secondary sources and error microphones. In this paper effects of some control parameters on the actively controlled sound field near the top edge of noise barriers are studied. Results of numerical study and model measurements are shown and discussed.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2010년도 춘계학술대회 논문집
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• pp.45-46
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• 2010

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 추계학술대회 논문집
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• pp.821-832
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• 2011

Recently, the noise of vehicle is the one of the key factors for customers to purchase a vehicle and the most important part which is related to the noise is the exhaust system. Thus, car makers have their own ways to assess this exhaust noise not only to decrease the level of noise but to enhance the feeling of it. Typically, to do these things in the early stage of development, the tuning code of the exhaust system has to be made by CAE tool, which is very reliable but expensive, and the prototype parts of this code would be made for the validation test. Then this process can be iterated to meet the target of the performance. In this study, a new algorithm which adapts the '3 dimensional convective sound wave theory 'and 'Doppler effect' has been developed. With this new algorithm, a brand new system for the calculation of tail pipe noise has been developed and validated by acoustic wind tunnel test. As a result of this study, various comparisons and have been carried out, for example, the comparison with other CAE tool has been performed for the validity and the improvement of the new calculation code could be achieved.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.100-103
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• 2005

The aim of the product noise labeling is to harmonize the noise control act relating to noise emission standards, conformity assessment procedure, marking, technical documentation and collection of data concerning the noise emission in the environment of equipment for use outdoors. It will contribute to the smooth functioning of the internal market, while protecting human health and well-being.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.81-84
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• 2007

THE THERE HAS BEEN AN INCREASING DEMAND FOR THE NOISE IMPACT ASSESMENT BY HIGH-SPEED TRAINS DUE TO THE EXPANSION OF HIGH-SPEED RAILWAY. THIS PAPER PROVIDES STRATEGIES FOR THE EVALUATION AND THE ASSESSMENT OF THE POTENTIAL NOISE IMPACT RESULTING FROM PROPOSED HIGH-SPEED RAILWAY. FIRSTLY THE NOISE TECHNICAL SPECIFICATIONS FOR THE RAILWAY NOISE HAVE BEEN REVIEWED, AND THE STRATEGIES OF THE NOISE IMPACT ASSESMENT FOR HIGH-SPEED RAILWAY NOISE ABATEMENT HAVE BEEN DESCRIBED.

• Journal of Mechanical Science and Technology
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• 제20권10호
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• pp.1653-1661
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• 2006

AC induction motors have been widely used for fan motor of the air conditioner indoor unit. Noise of these AC induction motors is usually caused by the coupling effects of structural and electrical systems. The rotating torque and the noise from AC induction motor were discussed in this paper,. First, the modification of motor was carried out in order to reduce the unbalance magneto motive force between main and sub winding. Second, structural modification based on normal mode analysis and modal testing was carried out so that the fan motor does not have the natural frequencies near the 2f-line frequency. Numerical modifications through these two processes were verified by experiments, which showed that the sound pressure level at 2f-line frequency of the modified system became about 25dB less than that of conventional one.