• 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.

• 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.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.371-376
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• 2003

The objective of this paper is to compare the site-to-site variability of ISO 10844 pass-by-noise test sites. In order to investigate the site-to-site variance of test surfaces, European commercial tires are tested at seven different test sites. Three Korea test sites and four Europe test sites are selected.. The pass by noise test is executed according to a 2001/43/EC regulation. A]though the ISO surface has a very specific track composition, it does not reduce the variation of pass-by-noise measurements over the surface of test sites. This paper shows that the test results of pass-by-noise level are different depending on the test sites. The correlation obtained in this work is able to predict the pass by noise level for certain test site using the data measured from another test site. 17he prediction value is range with an error within 1dB(A).

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.3
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• pp.116-121
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• 2005

The objective of this paper is to compare the site-to-site variability of ISO 10844 pass by the noise test sites. In order to investigate the site-to-site variance of test surfaces, European commercial tires are tested at seven different test sites. Three Korea test sites and four Europe test sites are selected. The pass by noise test is done according to a 2001/43/EC regulation. Although the ISO surface has a very specific track composition, it does not reduce the variation of pass by noise measurements over the surface of test sites. This paper shows that the test results of pass by noise level are different depending on the test sites. The correlation obtained in this work is able to predict the pass by noise level for certain test site using the data measured from another test site. The prediction value is range with an error within 1dB(A).

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.291-294
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• 2000

Analysis 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 technical approach for predicting tailpipe noise is used to identify the contribution of tailpipe noise to the pass-by noise in this study. Simulation program with a time domain engine modeling program called 'WAVE' and wave propagation theory of moving noise source are employed. Since the Doppler phenomenon causes a frequency shift during a pass-by noise test, the Doppler correction and time delay effects are incorporated into the estimation of tailpipe noise. The developed program can furnish an in-depth understanding of the effect of tailpipe to pass-by noise.

• 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.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1479-1486
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• 2000

This paper introduces the improved moving frame acoustic holography (MFAH) method and its application. MFAH allows us to visualize the noise generated by moving noise sources by employing a vertical line array of microphones affixed to the ground. The sound field generated by moving sources is different from that of stationary ones due to the movement of the sources. Therefore the measured sound pressure by the microphone on the ground has to be processed so that it cooperates the effect of the movement. This paper discusses the effect of moving noise sources on the obtained hologram by MFAH. This assures the applicability of MFAH to the visualization of moving sources. This paper also reviews the improved MFAH that can visualize a coherent narrow band noise and a pass-by noise. The practical applicability of the improved MFAH was demonstrated by visualizing tire noise during a pass-by test.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.4
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• pp.289-298
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• 2014

Pass-by noises of various trains were recorded by binaural recorder. The measured noises were evaluated using a sound pressure level and psychoacoustic metrics objectively. To analyze a binaural effect on annoyance that can be caused by train noise, auditory experiments were performed. Through the experiments, the annoyance differences between monaural and binaural train noises, the annoyance differences due to measurement angle and the annoyance differences due to kinds of train and measurement distance were determined. A correlation analysis was conducted to determine which index can affect the annoyance more strongly. As the result, a maximum rate of change of sharpness difference between left and right channels was proposed to predict the annoyance.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.10a
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• pp.475-476
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• 2010

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.296-297
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• 2012