• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.543-548
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• 2002

Nowadays since the customers of HDD's are interested in their noise levels in addition to their primary performances such as their average access time, capacity, HDD manufacturers make efforts on reducing the noise. The works to reduce noise are usually based on the measurable physical quantities such as SPL or acoustic intensity level. However, since the HDD noise is Judged by human beings, the basis of noise reduction should be human sensations. In this paper, the noise levels of various HDD's are evaluated by the human jury test to find a relationship between the physical quantities used for noise control and the human sensations of noise. Discrepancies are found in the judgments by the human beings and by the physical quantities. The loudness level, a psychoacoustic variable, is used to solve the discrepancy.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.184-185
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• 2009

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.05a
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• pp.598-599
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• 2010

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.3
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• pp.335-344
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• 2008

In recent years, public complaints against railroad noise by KTX and Ordinary train have been rising. Regulation of railways noise uses same standard without distinguishing the type of railroad cars. According to the type of railroad cars, the frequency characteristics of emitting noise is different. Therefore it is requested to know how the public response vary to each types of railroad cars. The noise annoyance from three types of trains(KTX, electric train, diesel train) was analyzed by jury evaluation test for assessing the effect of frequency characteristics. The numerical results by a semantic differential method showed that annoyance response to three type of trains depended on the frequency characteristics. As a result, this study proposed that the KTX could have a bonus level of maximum 2.9 dB(A) compared to ordinary train.

• The Journal of the Acoustical Society of Korea
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• v.36 no.1
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• pp.78-87
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• 2017

The goal of the present paper is to objectify the intrinsic subjectivity of sound as a media of music by applying psycho-acoustical methodology to the analysis of a musical work. First, 18 sound samples are extracted from "Symponie Fantastique" written by Hector Berlioz, which is a piece of program music, and then the objective Zwicher's sound quality parameters such as: Loudness, Sharpness, Roughness and Fluctuation Strength are evaluated for each of these sound samples. For subjective sound quality evaluation, 9 representative sound quality adjectives are extracted on a basis of program feature of Symponie Fantastique and the first jury test is carried out by using the numeric rating method and the paired comparison method. Three sound quality adjectives, "bright", "noisy", and "realistic" are extracted from the factor analysis of the first jury test result. On a basis of the computed sound metrics and the second jury test result for the three sound quality adjectives, three sound quality indexes are developed to represent the sound qualities of "Symponie Fantastique".

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.6
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• pp.550-555
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• 2012

Among the various elements affecting a customer's evaluation of automobile quality, buzz, squeak and rattle(BSR) have been considered to be major factors. In most vehicle manufacturers, the BSR problems are solved by find-fix method with the vehicle road test, mainly due to various excitation sources, complex generation mechanism and subjective response. To systematically tackle the BSR problems in early stage of the vehicle development cycle, these difficulties should be resolved. The aim of the present paper is to characterize the sound quality property of BSR noise that can be used to assess the subjective responses to BSR. The four sound metrics from Zwicker's sound quality parameter are computed for the signals recorded for eight BSR noise source regions localized by using the acoustic-field visualized results. Then, the jury test of BSR noise are performed. On the basis of the computed sound metrics and jury test result is evaluated to represent the harshness of BSR noise. It is expected that the developed BSR measuring system and sound quality properties can be used to reduce the automotive interior BSR noise in terms of subjective levels as well as objective levels.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.11
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• pp.1202-1213
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• 2009

Muffler sound quality of a vehicle has widely been evaluated using commercial softwares. However, the commercial softwares are providing only simple sound quality index. To get better sound quality evaluation method of the muffler, a new approach is suggested based on the subjective sound quality test. The suggested subjective sound quality evaluation method is refined with the fuzzy theory. The developed method is applied for the evaluation of various kinds of vehicle muffler sounds.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.145-148
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• 2004

Until now, product mostly has revealed physical quantities created by the standpoint of engineers. Consumers, however, perceive and evaluate products on the non-physical characteristics, such as feelings, emotions, and experiences in different social and cultural situations. Especially, for the household appliances such as a refrigerator, the sound is heavily related to the satisfaction of a customer who is a real user of the product and is very important factor to decide purchasing as well as visual design. Therefore, in this research, not only the simple sound pressure level but also the consumer's sense of hearing evaluate the noise from the refrigerator. And also, in order to improve the quality of sound through the design change, the consumer's evaluation is analyzed and related to the engineering quantities.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.447-452
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• 2012

Among the various elements affecting a customer's evaluation of automobile quality, buzz, squeak and rattle (BSR) are considered to be major factors. In most vehicle manufacturers, the BSR problems are solved by find-fix method with the vehicle road test, mainly due to various excitation sources, complex generation mechanism and subjective response. The aim of this paper is to develop the integrated experimental method to systematically tackle the BSR problems in early stage of the vehicle development cycle by resolving these difficulties. To achieve this aim, the developed experimental method ought to include the following requirements: to find and fix the BSR problem for modules instead of a full vehicle in order to tackle the problem in the early stage of the vehicle development cycle; to develop the exciter system including the zig and road-input-signal reproducing algorithm; to automatically localize the source region of BSR; to develop sound quality index that can be used to assess the subjective responses to BSR. Also, the BSR sound quality indexes based on the Zwicker's sound quality parameters using a multiple regression analysis. The four sound metrics from Zwicker's sound quality parameter are computed for the signals recorded for eight BSR noise source regions localized by using the acoustic-field visualized results. Then, the jury test of BSR noise are performed for participants. On a basis of the computed sound metrics and jury test result, sound quality index is developed to represent the harsh of BSR noise. It is expected that the developed BSR detection system and sound quality indexes can be used to reduce the automotive interior BSR noise in terms of subjective levels as well as objective levels.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.04a
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• pp.122-129
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• 2013

The vehicle's waning sounds are used for the purpose of informing the specific situation to the driver. In the past, the warning sounds were developed in terms of a simple notification. With the increasing importance of the emotional quality of vehicle, the research in terms of sound quality has been actively conducted. The desired sounds are dependent upon customer expectation and usage requirements. And it based on cultural or regional difference and personal preference. In this paper, the preference study considering the sale region and personal preference is introduced. Jury test for subjective evaluation are carried out and the difference in preference is analyzed.