• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.154-157
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• 2005

Generally, noise from a indoor air conditioner has been measured by overall sound pressure level, dB. Customers evaluation, however, of the noise from an air conditioners should not be depend on the only overall level but also the sensory feeling. Moreover, in this sensory evaluation, irregular, time-varying and uneven sounds which are difficult to describe itself by overall level are more affectable. Unfortunately however the formal evaluation method for this kinds of noise is not determined yet. In this research, the evaluation method for tonal noise, which is one of the unmeasurable sounds by overall level, is proposed to evaluate its acceptability based on the consumer's sense of hearing. To consider the consumer's sense, several times of Jury evaluation are carried out. The proposed approach could be applied to the other sound, which acoustical characteristics are similar to the tonal noise .

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.439-442
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• 2005

Generally, noise from a home appliance has been measured by overall sound pressure level or sound power level, dB. Customers evaluation, however, of this noise should be depend on the only overall level but also the sensory feeling, annoyance, unpleasure and so on. Moreover, in this sensory evaluation, irregular, time-varying and uneven sounds which are difficult to describe itself by overall level are more affectable. Unfortunately however the formal evaluation method for this kinds of noise is not determined yet. In this research, the evaluation method for harmonic noise, which is a major noise from home appliance and one of the unmeasurable sounds by overall level, is proposed to evaluate its acceptability based on the consumer's sense of hearing. The proposed approach could be applied to the other sound, which acoustical characteristics are similar to the tonal noise.

• International Journal of Naval Architecture and Ocean Engineering
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• v.4 no.4
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• pp.374-385
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• 2012

The indoor noise of a ship is usually determined using the A-weighted sound pressure level. However, in order to better understand this phenomenon, evaluation parameters that more accurately reflect the human sense of hearing are required. To find the level of the satisfaction index of the noise inside a naval vessel such as "Loudness" and "Annoyance", psycho-acoustic evaluation of various sound recordings from the naval vessel was performed in a laboratory. The objective of this paper is to develop a single index of "Loudness" and "Annoyance" for noise inside a naval vessel according to a psycho-acoustic evaluation by using psychological responses such as Noise Rating (NR), Noise Criterion (NC), Room Criterion (RC), Preferred Speech Interference Level (PSIL) and loudness level. Additionally, in order to determine a single index of satisfaction for noise such as "Loudness" and "Annoyance", with respect to a human's sense of hearing, a back-propagation neural network is applied.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.7
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• pp.650-656
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• 2011

The noise inside a naval vessel is very important in considering the need for hearing protection, improving the working environment and maintaining good communications for crews living on board a naval vessel. The indoor noise of a ship usually is specified by the A-weighted sound pressure level, but other evaluating parameters are required to reflect human senses more effectively. This paper uses additional noise indices related to room acoustics, such as NR(noise rating), NC(noise criterion), RC(room criterion), PSIL(preferred speech interference level) and loudness level to evaluate the noise inside cabins on a naval vessel. Using these psychological noise indices, allowable limit of noise level in cabins is suggested through psycho-acoustic evaluation for the noise in cabins.

• International Journal of Automotive Technology
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• v.7 no.1
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• pp.43-49
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• 2006

In this paper, an index for the evaluation of a vehicle intake booming noise and intake sound quality were developed through a correlation analysis and a multiple factor regression analysis of objective measurement and subjective evaluation data. At first, an intake orifice noise was measured at the wide-open throttle test condition. And then, an acoustic transfer function between intake orifice noise and interior noise at the steady state condition was estimated. Simultaneously, subjective evaluation was carried out with a 10-scale score by 8 intake noise and vibration expert evaluators. Next, the correlation analysis between the psychoacoustic parameters derived from the measured data and the subjective evaluation was performed. The most critical factor was determined and the corresponding index for intake booming noise and sound quality are obtained from the multiple factor regression method. And, the optimal design of intake system was studied using the booming noise and the sound quality evaluation index for expectation performance of intake system. Conclusively, the optimal designing parameters of intake system from noise level and sound quality whose point of view were extracted by adapting comparative weighting between the booming noise and sound quality evaluation index, which optimized the process. These work could be represented guideline to system engineers, designers and test engineers about optimization procedure of system performance by considering both of noise level and sound quality.

• Journal of Environmental Impact Assessment
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• v.19 no.6
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• pp.553-561
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• 2010

Railway noise barrier is generally used with welding of joint rail for railway noise reduction in our country. In this study, method for performance evaluation of railway noise barrier using insertion loss was suggested in case of without having noise measurement results before barrier installation. For this, railway noise measurements were performed in commercial high-speed railway site which has railway noise barrier. As a noise level before noise barrier installation, predicted noise level were used. From this method the performance evaluation for railway noise barrier were performed accurately and efficiently.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.790-795
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• 2004

The characteristics of refrigerator noise recorded in anechoic chamber was investigated in condition of a the real living room and a kitchen. To predict the noise propagation in an apartment unit, room acoustic simulation software was used. It was found that the noise level in the real living room was $4\sim8dB$ higher than in the anechoic chamber. When a noise barrier and absorption materials were used on the rear wall and floor, the noise level reduced up to $3\sim4dB$. In addition, when the subjective evaluation of auralized refrigerator noise was undertaken using headphone, it was revealed that 21dB (A) is the allowable sound pressure level of 95% satisfaction.

• The Journal of the Acoustical Society of Korea
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• v.22 no.2E
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• pp.87-92
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• 2003

In this paper, a new speech enhancement method using level adapted wavelet packet is presented. First, we propose a level adapted wavelet packet to alleviate a drawback of the conventional node adapted one in noisy environment. Next, we suggest an adaptive noise estimation method at each node on level adapted wavelet packet tree. Then, for more accurate noise component subtraction, we propose a new estimation method of spectral subtraction weight. Finally, we present a modified spectral subtraction method. The proposed method is evaluated on various noise conditions: speech babble noise, F-l6 cockpit noise, factory noise, pink noise, and Volvo car interior noise. For an objective evaluation, the SNR test was performed. Also, spectrogram test and a very simple listening test as a subjective evaluation were performed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.427-430
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• 2005

The quality of various noises generated in the refrigerator is one of the important factors in deciding quality of the product. The main focus of sound control design has been shifted from reduction of sound level to improvement of sound duality for customer's preference. Up to date the purpose of noise control is the minimization of noise level. However despite of gradual decrease of noise level, occasionally the perceptional quality of noise has not been improved. In this paper, the relation between subjective and objective evaluation of sound quality has established and sound quality index is developed using ANN for evaluation of refrigerator's noise of both the starting noise and the stable running noise of compressor. To verify the usefulness of the index, the results in this paper have been compared with those surveyed by Consumer Union in USA.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.5 s.110
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• pp.503-513
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• 2006

The duration time of aircraft noise event is also an important factor for the evaluation of civil aircraft noise, which is considered as a notable characteristic of military aircraft noise. SEL is proved as a suitable noise metric for the measuring military aircraft noise of various flight pattern considering the duration time of noise event. This study reviews whether SEL is a suitable for measuring civil aircraft noise and study shows SEL is fairly compensating the duration time of civil aircraft noise event for the evaluation of aircraft noise. Noise metric for the evaluation aircraft noise based on SEL is more appropriate than based on $L_{MAX}$ for compensating duration time of noise event either military aircraft or civil aircraft. In this reason, current formula of WECPNL based on energy average of measured $L_{MAX}$ for the evaluation of aircraft noise impact in 'Test Method of Noise and Vibration of Korea' is recommended to be amended to formula of WECPNL based on energy average of measured SEL considering compensation of noise event duration time, if WECPNL is not based on measured EPNL, a metric compensating duration time.