• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.04a
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• pp.462-465
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• 2014

It is well known that tire/road factors have a large influence on overall tire performance. In this paper, the basic study on the effects of tire/road factors on the pass-by noise performance of tire labeling has been carried out through experimental tests. The tire pass-by noise is affected by road characteristic factors, especially greatly influenced by road friction coefficient, and the next dominant factor is road chipping size. For several authorized pass-by noise test tracks, the pass-by noise correlation test has been done to know the test site effect, which results in 2~3dB(A) variation of pass-by noise level. Finally, it is shown that the winter tire is differently influenced by the pass-by noise test track characteristics, as compared to all-season tire and summer tire.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.1
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• pp.10-16
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• 2013

This paper discussed a procedure for noise certification of Aircraft and predicting the full scale over-flight noise of propeller from acoustic wind tunnel measurement of small scale propeller. Noise Certification Procedures is established from International Civil Aviation Organization(ICAO). The data manipulations are then discussed in extrapolation to simulation flight distance and flight simulation. One of the most important point of flight simulation is adjustments for differences between wind tunnel test conditions and flight test conditions. To simulated the noise level estimation procedure for noise data post-process, simulate procedures from data of the wind tunnel noise measurement and the flight noise measurement by using a 7kg degree UAV. This study confirmed an effectively noise estimation procedures by wind tunnel noise test and flight noise test.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.181-186
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• 2001

High speed railroad noise is one of the main causes of environmental impact. An estimate of the relevant noise levels is usually required in order to evaluate the noise barrier and the anti-noise trailer. This paper introduce the test procedure and the estimate for HST noise. The aim of this is to measure, by means of a test, the level of acoustic pressure present during the passing of a KTX(Korea Train Express), in order to satisfy the contractual requirements and the noise criteria. A number of measurements are carried out in order to estimate noise impact by HST along test track.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.871-875
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• 2001

Evaluation of the contribution of each pass-by noise source to the overall pass-by noise is an important issue for reduction of pass-by noise. A lead-wrapping test for analyzing pass-by noise of motorcycle is used to identify the principal noise sources of the pass-by noise in this study. Lead-wrapping test is employed and the contribution analysis is carried out. Based on the contribution analysis of each pass by noise source from the action of the prior tests, the design modifications of intake/exhaust systems were performed for reducing the pass-by noise. Finally, the pass-by noise test based on ISO362 was carried out to verify the noise reduction.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.2 s.107
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• pp.124-131
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• 2006

This study introduces an environmental noise evaluation procedure for wind turbines(W/T) and the evaluation result of a 750 kW wind turbine(W/T) system. Test and evaluation are performed according to the international standard IEC 61400-11 on J48 W/T which is under operation in Daekwanryung W/T test site. With the meteorological data and W/T operational data, noise data are monitored and analysed. An integrated monitoring system is constructed in the test site and is utilized for the evaluation. From the measured noise data, acoustic power level, directivity and tonality of the W/T are estimated under the wind speeds required fly the International standard. The purpose of the study is to establish an W/T noise evaluating system satisfying the international standard and to obtain noise data for home made 750 kW W/T.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.451-456
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• 2004

In this study, evaluation was carried out for reduction method of floor impact noise through field test and the effective methods for heavy impact noise were proposed. As a field test, impact noise reduction materials such as EPP, EEPS, EVA, PE and so on, did not satisfied the recommandation value at the condition of 150mm thickness concrete slab. The evaluation results for those materials by 'inverse A curve' showed $53\sim55dB$ at heavy impact noise and $53\sim58dB$ at light impact noise. But, two methods proposed by authors were evaluated $47\sim50dB$ at heavy Impact noise and $54\sim58dB$ at light Impact noise on the similar concrete slab thickness.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.754-757
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• 2005

Aircraft noise is the serious problem for inhabitants near an air force base. Noise by ground test of aircraft, however, can be minimized through test room construction. In this study, environmental effects of the noise by aircraft ground test were investigated by experiments under the standard act and by performance, prediction of the Hush house, constructed for the noise reduction.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.241-245
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• 2005

This study introduces the wind turbine (W/T) noise evaluation procedure required in the international standard (IEC 61400-11) and monitoring system for the evaluation. Noise emission characteristics of a 750kW W/T generator is investigated. Test and evaluation are performed on J48 W/T model which is under operation in Daekwanryung Wind Test Site. With the noise signal, meteorological data and W/T operational data are monitored in real time by the integrated monitoring system using LabVIEW. From the measured noise data, acoustic power level and tonality of the W/T are estimated under the wind speeds required by the international standard.

• Transactions of the Korean Society of Automotive Engineers
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• v.25 no.3
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• pp.344-349
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• 2017

Suspension noise from under a passenger car is one of the important factors that impact the perceptual quality for drivers. However, it is difficult to validate this by component level testing in the early stage of development, because suspension noise caused by interaction of the related parts has been found at saleable vehicles late during development or at the manufacturing stage, when many customers have already filed for claims. This study proposed a validation testing under research by the DFSS process that enables reproduction of vehicle level noise by component level testing using a shock absorber with the related parts, such as urethane bumper and top mount. This study also developed a compromised test matrix while analyzing the noise factors through experimental design and analysis of variance to determine what factors can affect noise. Based on this study, we expect that the vehicle level and customer claim can be validated during initial development timing by a more reliable component noise validation test.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.8
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• pp.694-701
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• 2018

Civil aircraft noise certification standard is based on the ICAO Annex 16 Vol. 1. And, the standard uses A-Weighted SPL, EPNL and SEL method depending on the aircraft category. Korean noise standards, KAS 36 and other nation's CS 36 and FAR 36 noise standards were developed and revised according to the international noise standards, ICAO Annex 16. And, the national noise requirements are equivalent each other. The small airplane noise certification requires only take-off noise level with A-Weighted SPL in dB(A) unit. The first Korean aircraft noise certification was performed for the KC-100 certification in August 2012 with Korean authority and U.S. FAA. The noise certification requires much knowledge and experience in flight tests and noise data processing. In this study, the noise test requirements, test conditions and data correcting methods are shown with the test examples.