• The Journal of the Acoustical Society of Korea
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• v.40 no.6
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• pp.566-570
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• 2021

This study presents a perceptual difference in acceleration sounds of a sporty sedan between the driver and passenger. We found a significant difference in annoyance and sportiness perception according to the acceleration sound level through subjective evaluations. The multimodal reproduction system, which can reproduce the driving image, motion, vibration, and sound, was applied for the test. A subjective experiment was conducted to evaluate the perceived intensity of annoyance and sportiness by varying the acceleration sound level in five steps of 3 dB. The experimental results showed that the driver perceives the acceleration sound less annoying than the passenger at a relatively low sound level. Meanwhile, the driver has perceived the acceleration sound more sporty than the passenger at a relatively high sound level. Moreover, it was found that passengers were 35 % less sensitive to an annoyance than drivers, whereas the driver was 74 % more susceptible to sportiness than passengers according to the sound level change. This finding is expected to be applied as a sound design strategy that differentiates the acceleration sound level in active sound design.

• The Journal of the Acoustical Society of Korea
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• v.42 no.3
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• pp.181-188
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• 2023

In a typical living space, windows are directly exposed to the external noise environment. The best way to reduce outside noise is to block it from the outside, not the inside. Exterior blinds for blocking sunlight are commercialized in various ways. However, it has not yet been actively utilized in Korea. In the previous study, an experiment was conducted in an accredited laboratory to verify the sound insulation performance of an external motorized blind manufactured for shading. And it was verified that there is a sound insulation performance of 6 dBA compared to the reduction performance of a general window. In this study, we tried to confirm the reduction performance by applying the sound insulation performance of external electric blinds to windows in actual living spaces. In addition, an improvement plan was sought to increase the effective noise reduction performance. As a result of the measurement, the reduction performance of the external motorized blind itself was insufficient at the level of 1 dBA to 3 dBA. However, additional reduction performance of the 2 dBA level was confirmed by filling the gap between the blind slits.

• Journal of the Korean housing association
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• v.17 no.5
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• pp.47-54
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• 2006

This study aims to evaluate the sound insulation performance of Korean traditional paper(Hanji) windows as a material of environmental friendly building. Six types of traditional windows with 4 types of traditional window positions, were installed in l/2.5 scale model house. And then according to KS F 2235, comparative sound level differences between outdoor and indoor were measured. The main results are as follows; 1) TL(Transmission Loss) of Korean traditional paper windows, which cover one eighth of total balcony window, are ranged from 15 to 19 dB(A) in the living room and from 8 to 11 dB(A) in the balcony space. 2) TL of Korean traditional paper windows, which cover one fourth of total balcony window, are ranged from 10 to 19 dB(A) in the living room and from 8 to 10 dB(A) in the balcony space. 3) TL of Korean traditional windows with one side-one layer paper is ranged from 10 to 21 dB(A) and two side-one layer paper is 15 to 23 dB(A) and two side-two layer paper is 19 to 23 dB(A) respectively.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.778-781
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• 1995

In this paper, sound radiation of a rotary compressor used in room air-conditioner is investigated. structural eigenmodes are identified through modal test. Since accumulator is found important factor of sound radiation, damping material was added around accumulator to reduce sound radiation level of rotary compressor. As result, sound radiation was reduced to 3 dB.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.2
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• pp.191-198
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• 2010

The noise by the construction activities is one of the main issues in Korea. To prevent the noise from construction site, construction company installs temporary noise barriers along the construction site boundary. Normally sound insulation performance ($R_w$) of the temporary noise barriers made by metal or plastic is between 18 and 31 dB and metallic noise barriers are around 5 dB higher than plastic noise barriers. Sound absorption performance (NRC) of the temporary noise barriers are between 0.20 and 0.59 so it's difficult to characterize their acoustic performance. In this study, it has founded that sound insulation performance of the temporary noise barrier has been improved about 3dB by stick the high density acoustic sheet and insertion loss of noise barrier is getting increased as the source and receiver approached the temporary noise barriers.

• The Journal of the Acoustical Society of Korea
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• v.20 no.4
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• pp.17-21
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• 2001

There are some methods to enhance the ‘sweet spot’in loudspeaker-based 3D audio systems. Most of them can be only applied to narrow frequency band inherently. In this paper, we introduce the more robust 3D sound reproduction system which has far wider robust bandwidth. The system applies a sum and difference filter to the conventional three loudspeaker-based one.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.25 no.6_2
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• pp.625-633
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• 2007

Recently human beings are enforcing marine investigations to extend their living environment from land to the sea. Therefore, this study grasped objects in the bottom of the sea and its topographical undulation and acquired topographic map with a sound detector. In result, This study acquired their images with a sound detector and can draw up a Drawing of Sea Mapping and a three-dimensional modeling map.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.46 no.4
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• pp.449-457
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• 2010

This study shows that the vertical migration speed of sound scattering layers (SSLs), which is distributed in near Funka Bay, were measured by 3D velocity components acquired from a bottom moorng ADCP. While the bottom mooring type has a problem to measure the velocity vectors of sound scattering layer distributed near to surface, both the continuous vertical migration patterns and variability of backscatterers were routinely investigated as well. In addition, the velocity vectors were compared with the vertical migration velocity estimated from echograms of Mean Volume Backscattering Strength, and estimated to produce observational bias due to SSLs which is composed of backscatterers such as euphausiids, nekton, and fishes have swimming ability.

• Journal of Magnetics
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• v.4 no.3
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• pp.98-101
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• 1999

In this work we htave constructed an under water sonar transducer using Terfenol-D rod employing open magnetic circuit. Normally Sonar transducer using Terfenol-D was designed under closed magnetic flux return path, and permanent magnet for dc bias marnetic field, but high magnetic field should be applied to the transducer coil for high sound power and it brings temperature increase inside of the transducer. To improve this heat dissipation problem, we have designed an open magnetic circuit type transducer and we can get 200 dB (re. 1 Pa @ 1m) sound power for the input power of 650 VA.

• Journal of Broadcast Engineering
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• v.11 no.4 s.33
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• pp.448-457
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• 2006

HRTF DB, including the information of the sounds which is arrived to our ears, is generally used to make a 3D sound. But it can decline some three-dimensional effects by the confusion between front and back directions due to the non-individual HRTF depending on each listener. In this paper, we propose a new method to use psychoacoustic theory that reduces the confusion of sound image localization. And we make use of an excitation energy by the sense of hearing. This method is brought HRTF spectrum characteristics into relief to draw out the energy ratio about the bark band. Informal listening tests show that the proposed method improves the front-back sound localization characteristics much better than the conventional methods.