• Journal of Biomedical Engineering Research
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• v.34 no.4
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• pp.204-211
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• 2013

In this paper, an algorithm for suppressing acoustic noises contained in stethoscope sound is proposed and implemented in real-time using an embedded DSP system. Sound collected by stethoscope is down-sampled and band-pass filtered, and later an NLMS adaptive filter is used to cancel the acoustic noise induced from external noise sources. Also, the unpredictable impulsive noises due to fabric friction and instantaneous tapping are detected using the SD-ROM algorithm, and suppressed using an algorithm approximating the morphology filter. The proposed algorithm was tested using signals collected with a digital stethoscope mockup, and implemented on an ARM920T-based DSP system.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.12
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• pp.1117-1126
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• 2013

The standard impact sources, standardized to rate the sound insulation performance of floor structure, should simulate well the real floor impact sources, which is very important to grade the floor structure then to establish counter plan to improve the performance of floor. Recently the tire, the standard heavyweight impact source, has been discussed that the impact force is too big to represent the real impact force. And researches have been carried on the applicability as a substitute or a supplementary. In addition, tapping machine, the standard lightweight impact source, is also questionable if it is representative of real lightweight impact source. This study aims to examine the similarity of standard impact sources with living impact sources, comparing the physical characteristics such as impact force, frequency contents and sound level. The result showed that the physical characteristics of standard impact sounds were somewhat different with that of living impact sounds, and the standard sources couldn't be verified from this result. Later subjective evaluation should be followed to compare how the physical differences make relationship with the subjective differences.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1167-1172
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• 2007

This study investigates human floor impact sounds; not only the children's jumping and running represented by heavy-weight impact source such as bang machine and impact ball but also the high-heel walking and the light weight object dropping represented by tapping machine in the standard measurements. However, due to reliability problems as a standard impactor, bang machine has not been included in the new draft of ISO 10140 Part 3: Measurement of impact sound insulation. Therefore, the procedure to convert the floor impact sound level of the bang machine into that of the impact ball has been demanded because the bang machine has been only the standard heavy-weight standard impact source and much of its data has been collected, This study indicates that the use of impact ball is reliable and that the bang machine data can be successfully converted into the impact ball data in case of box-frame type reinforced concrete structures.

• Journal of the Society of Naval Architects of Korea
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• v.45 no.6
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• pp.719-725
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• 2008

In this paper, noise and vibration reduction for floating-floored ship cabin is studied. A mock-up is built by using 6 mm steel plate, and two identical cabins are made for simulation of ship cabins. When a speaker is used as a sound and vibration sources, it is shown that floating floor is more effective in isolating sound than bare deck by 2-5 dB. It is also shown that structure-borne noise of the bare deck is greater than that of floating-floored deck by 3-10 dB. For tapping machine excitation, it is found that the effect of floating floor in airborne noise and structure-borne noise reduction reaches up to 40-50 dB for high frequency ranges.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.1243-1246
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• 2006

As remodeling market is growing and peoples' concern on health and well-being is getting high, there is a need to apply environmentally friendly approach to remodeling an apartment houses. But, in point of the impact noise concerned, the thickness of the concrete slab and the limited ceiling height of the remodelling houses are the main constraints to improve the impact noise performance. In order to investigate the effect of the impact noise isolation as structural treatments for the structural elements, heavy-weight impact noise and tapping noise were measured in an remodeling building. As a result, structural strengthening method by H-beam was successful to enhance the impact noise level at about 3 or 4 class by the sound classification system.

• Phonetics and Speech Sciences
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• v.13 no.2
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• pp.67-76
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• 2021

Nanta means "tapping" using percussion instruments such as drums, which is the rhythm of Samulnori, a tradtional Korean music. Nanta speech rhythm intervention program was developed and applied for the children with limited speech sound production and investigated its effect. Nanta program provided audible stimulation, various sound loudness and beats, and rhythms. Nanta program consists of three stages : Respiration, phonation and articulation with the rhythm. Six children with language development delay participated in this study. Children were encouraged to explore sounds and beats and freely express sounds and beats. Along with the rhythm, children also were encouraged to produce speech sounds by increasing the length of syllables in mimetic and imitating words. A total of 15 sessions were conducted twice a week for 40 minutes per session. For exploring the effectiveness, raw scores from preschool receptive-expressive scales (PRES) and receptive-expressive vocabulary test (REVT) were obtained and compared before and after therapy. The results demonstrated that significantly improved receptive (p=.027) and expressive language scores (p=.024) in PRES and receptive (p=.028) and expressive (p=.028) vocabulary scores following intervention using Wilcoxon signed-rank test.These findings suggest that the nanta rhythm program can be useful for improving language development and vocabulary in children with limited speech sound production.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.223-226
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• 2017

With the development of information technology, users are provided with information they want through mobile device in various situations. When users communicate with information, there is interaction through gesture activities such as tapping and experience in the process. Experience through interaction in mobile affect the user's psychology. This is important because it is related to the behavior of the user in the future. Various types of information presentation methods have been researched in mobile environment. However, there are more research focusing on functional interactivity. The purpose of this study is to investigate the effect of interaction and usage mode on satisfaction, usefulness, and intention to use for sound text presentation that is user-centered. As variables for my study, there are two factors which are interactivity and usage mode. The interactivity type is composed of two ways that are: High and Low depending on modality and message interactivity; and the usage mode is composed of Action mode and Goal mode depending on whether user has a task or not. The experimental design is $2{\times}2$. The same content is provided in (a) only Modality interactivity, and (b) Modality and Message interactivity are provided. Depending on usage mode, (a) Action mode is processed without a specific task, and (b) Goal mode is performed with a specific task to participants. The experimental study demonstrated that there is a difference in satisfaction, usefulness, and intention to use depending on the difference of interaction and usage mode when providing information in mobile environment. The results of this study are summarized as follows: interaction and usage mode have significant influence on mobile user's satisfaction, usefulness, intention to use.