• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.271-274
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• 2005

For noise and vibration order-analysis on rotating machinery, it is compulsory to measure the RPM of the rotating part of the machine. Normally the RPM is measured using dedicated tacho-probes. In this paper we describe a new method that in real-time synthesizes a tacho signal from the measured noise or vibration signal thus eliminating the tacho probe. The method strengths and weaknesses are evaluated on practical signals.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2011년도 춘계학술논문집 2부
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• pp.525-528
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• 2011

Noise emitted by driving cars affects our daily life, penetrating wherever man lives or works. There are three types of possible sound emitting processes that are aerodynamic sources, air pumping and tire vibration. In this paper, a theoretical model has been studied to describe the sound radiation by the surface vibration of running tires and experimental verification has been conducted to evaluate sound radiation characteristic due to tire vibration.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 춘계학술대회 논문집
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• pp.526-531
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• 2011

A dash panel component, close to passengers, plays a very important role to protect heat and noise from a power train. Meanwhile, it is also a main path that transfers vibration energy and eventually radiates acoustic noise into the cavity. Therefore, it seems important to provide an optimal design scheme incorporating sound packages such as dash isolation pad and carpet, as well as structures. The present study is the extension of the previous investigation how design variables affect sound radiation, which was carried out using the simple plate and framed system. The system taken into account in this paper is a dash panel component of a sedan, which includes A pillar, front side member, dash panel and the corresponding sound packages. Design variables such as panel thickness and sound package layers are investigated how they are related for the better radiation performance (i.e. structure-borne) and sound transmission loss (i.e. air borne).

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 추계학술대회 논문집
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• pp.727-732
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• 2009

The objective of this study is to analyze and evaluate design factors relating to sound reduction performance in dry wall system. The main contents of this study are as follows. 1) Analysis and pre-evaluation of sound reduction performance of drywall system ; The sound reduction performance was pre-evaluated by INSUL simulation and these results of analyzing walls were analyzed by screening DOE(design of experiment) for selecting major factors that dominant influence the sound reduction performance. These main factors relating to sound reduction performance can be used for development of 1st grade sound reduction performance drywall system. 2) Design and evaluation of 1st grade sound reduction performance drywall system; The evaluation test of the sound reduction performance gave vaues higher than 1st grade (Rw+C=64). When campared with existing dry wall system, respectivelly, the new system shows performance higher than 8 dB.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2010년도 추계학술대회 논문집
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• pp.586-591
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• 2010

The sound field can be classified to the direct and reverberant sound field. If the sound absorption material in a room is not applied sufficiently, the reverberant sound field increases and the sound pressure in a room also increases when the sound source exists in a room. Therefore, the reverberation time should be controled in order to reduce the reverberant sound as well as sound pressure level in a room. Even though the reverberation time is specified and researched widely in architectural engineering, it is rarely performed in a marine engineering. Therefore, in this research, the reverberation time in a navel vessel is researched related to the noise reduction in a cabin.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.492-497
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• 2006

This study gives the results of the measurements and analysises of the reverberation times in a small room such as apartment houses. We measured the RT by changing measurement conditions, which were sound sources. sound source's positions, receiving point & height, sampling time and so on. The critical factor affecting reverberation time was sound source in unoccupied houses and the reverberation time differences between result of RT using impulsive and interrupted sound source was 0.3sec at 500Hz frequency. And the difference of RT due to sound sources affected the sound insulation such as apparent sound reduction index and sound level difference about 1dB at each frequency in unoccupied houses.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.671-674
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• 2006

Heavy-weight impact sounds generated by impact ball were classified according to the frequency characteristics on the equal loudness contours. Sound quality metrics such as Zwicker's loudness, sharpness, roughness of each classified impact sound were also measured. Loudness spectrum has been regarded as an indication of the characteristics difference of each classified impact sound. The adjectives in Korean expressing the sound quality characteristics of floor impact sounds were also investigated by adoptability and similarity tests. The group of the adjectives was used to evaluate the sound quality of floor impact sound by semantic differential test method.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.1003-1008
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• 2004

In our life, we have used many digital appliances. They helped us to improve the quality of lift but sometimes gave us unsatisfactory result because they produce specific noise. Especially a vacuum cleaner produces a great deal of noise that is very annoying. So we need to study what sound metrics affect human sensibility. In this paper, we will study sound quality index for vacuum cleaner. The subjective evaluation of vacuum cleaner sound can be indicated to objective parameters by sound metrics of psychoacoustics. The artificial neural network can estimate the nonlinear characteristics of relation between subjective evaluation and sound metrics. We applied the artificial neural network to the development of sound quality index for vacuum sound.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.785-790
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• 2014

The purpose of this study is to identify the significant sound quality metric and compose the sound quality index of motor driven roller blind which is part of vehicle sunroof. Before subjective evaluation, sound characteristics of roller blind was analyzed and set the target operating sound for subjective evaluation. Thus, transfer sound of roller blind which has the characteristics of sound modulation was used for subjective evaluation. Linear regression was carried out by chosen Zwicker's metrics which are pointed by comments of jurors. Loudness and sharpness related metrics are prime metrics in sound quality index we composed. Effect of roller blind assay when it is attached to real vehicle was identified to evaluate the validity of index.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.419-422
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• 2014

Floor impact sound level is affected by various factors. This study was examined about impact sources and floor coverings influenced at floor impact sound. So this study wishes to get method to reduce sound pressure level of receiving room. Light-weight impact sound in mid frequency and Heavy-weight impact sound in low frequency was affected by floor coverings. Therefore, method to reduce floor impact sound level is to use proper floor coverings. Some coverings can amplify the heavy-weight impact sound in low frequency. Floor impact sound sources used measurement and analysis were standard heavy-impact source(Tapping, Bang, Ball) and living impact sources(Cleaner, Chair, Toy-car, Soccer ball). And Floor coverings used measurements were various thickness vinyl, laminate(or ply-wood) floor. Especially vinyl floor coverings were very effective method to reduce floor impact.