• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.696-700
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• 2007

In case of dome-typed gymnastics training floor, since its form takes shape of the focus of sound, in the occasion when the finishing-material was used with the sandwich panel that prominent in reflexibility, and because the reverberation of sound in indoor is too loud, a smooth practice and teaching is very difficult. As this indoor gymnastics training floor, standing at its character, is required simultaneously the idea communication between the player and the coach, and the acoustic capability regarding to the clearness of music, besides the sport activity, the method to minimize the acoustic defect should be urgently contrived from the stages of design and beginning of construction. On this viewpoint, after investigation on the confidence of the surveyed value and the estimated value using acoustic simulation, and use of the changed finish-material, this thesis intends to design the dome-typed gymnastics training floor that secured the optimized acoustic condition. It is also considered that such result of the study could be utilized as the useful data that enables to improve the retrenchment effect of the construction cost as well as the acoustic performance, by means of the prediction control on the acoustic problem from the stage of design, for the occasion when the similar indoor sport gymnasium is planning to build for the near future.

• The Journal of the Acoustical Society of Korea
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• v.22 no.8
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• pp.680-686
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• 2003

Digital waveguide model is a general method that is used in physical modeling of musical instruments. Wave motion is analyzed by time or by space in digital waveguide model. Because sampling is made via time, it is general that musical instrument model is described by wave motion of time. In this paper, we synthesized the musical instrument sound by adding instrument body model to the spatial based string model. In this way, we could improve sound quality and process musical instrument model's tone control variables effectively. We explained about delay error that happens in string and body in space based sampling and showed method to process fractional delay using FD (Fractional Delay)filter. Finally, we explained the relation between tone quality and number of delays. And we also compared the result with time base digital waveguide model.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.4
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• pp.753-758
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• 2009

This paper is proposed the hardware structure and signal processing method of the RF-Tag based on heart sound to develop the mobile biomedical information device for the u-healthcare system. The RF-Tag in this study is consisted of a skin temperature sensor, a dynamic microphone for heart sound detection, Bluetooth communication to transmute healthcare data, and pulse period detection algorithm with adaptive gain controller. We experimented to evaluate performance of the RF-Tag in noisy environments. In addition, the RF-Tag has shown the good performance in the results of experiment. If the proposed methods in this study apply to design the u-healthcare device, we will be able to get the exact health data on real time in mobile environments.

• The Plant Pathology Journal
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• v.35 no.6
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• pp.609-622
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• 2019

Sound vibration (SV) treatment can trigger various molecular and physiological changes in plants. Previously, we showed that pre-exposure of Arabidopsis plants to SV boosts its defense response against Botrytis cinerea fungus. The present study was aimed to investigate the changes in the proteome states in the SV-treated Arabidopsis during disease progression. Proteomics analysis identified several upregulated proteins in the SV-infected plants (i.e., SV-treated plants carrying Botrytis infection). These upregulated proteins are involved in a plethora of biological functions, e.g., primary metabolism (i.e., glycolysis, tricarboxylic acid cycle, ATP synthesis, cysteine metabolism, and photosynthesis), redox homeostasis, and defense response. Additionally, our enzyme assays confirmed the enhanced activity of antioxidant enzymes in the SV-infected plants compared to control plants. Broadly, our results suggest that SV pre-treatment evokes a more efficient defense response in the SV-infected plants by modulating the primary metabolism and reactive oxygen species scavenging activity.

• The Journal of the Acoustical Society of Korea
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• v.16 no.3E
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• pp.50-55
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• 1997

Based on the anthropometric data of Korea male adults, a head and torso simulator(HATS) is constructed to measure its head related transfer functions (HRTFs) which can be used for three dimensional (3-D) sound localization. The HRTFs binaural impulse responses, are measured in an anechoic chamber using a burst maximum length sequence (MLS) signal of 65,535 samples and 32,768 samples acquisition at the sampling rate of 75.47kHz. Also measured are the impulse responses of a driving loudspeaker and some headphones for sound reproduction to get the exact HRTF of the HATS-alone. Through a post-processing procedure, the impulse-version HRTFs at the sampling frequency of 44.1 kHz, which have filter lengths of 512 points, are finally obtained. As an application of the measured HRTFs, a 3-D sound processor for headphone reproduction has been developed. The signal intervals to be processed can be selected and each interval is manipulated to have its diretionality and distance information by using corresponding HRTF and energy control.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.5
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• pp.629-635
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• 2006

Manufacture of motor by laser has been studying realization that was demands on market for lightening and miniaturization. Moreover. early in the 1980s. manufacture of parts for automobiles by laser welding was already successfully introduced. The purpose of this study was to develop production technology of the high quality laminated stator core for motor by pulsed Nd:YAG laser heat source. In the event of adjusting defocus and voltage to control humping in laser welding of the laminated core. sound bead could be obtained. but deep penetration was not. Therefore. explosive evaporating plasma was controlled by adjustment of peak power on pulse width. Particularly, because explosive evaporating plasma induced high peak power, made molten metal in keyhole scatter. a suitable adjustment of peak power was required to obtain sound bead. As a results of experiment. sound bead and deep penetration could be obtained.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.5
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• pp.603-609
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• 1999

The effect of an external acoustic excitation on the wake structure behind a circular cylinder was experimentally investigated. The sound wave was excited in the frequency range of the shear layer instability and two sound pressure levels of 114 and 120dB were used in this study. As a result, the acoustic excitation modified the wake structure by increasing the velocity fluctuation energy without changing the vortex shedding frequency. The acoustic excitation enhanced the vortex shedding process and promoted the shear layer instability. Consequently, the acoustic excitation reduced the length of the vortex formation region and decreased the base pressure. In addition, the vortex strength of vortices was increased and the width of the wake was spread out due to the acoustic excitation. When the excitation frequency was identical to the shear layer instability frequency, the effect of the external flow control on the cylinder wake was maximized. In addition, with increasing the sound pressure level, the effect of the external acoustic excitation on the wake structure increased.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.630-635
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• 2012

Nearfield acoustic holography method predicts an unmeasured sound field, therefore it depends on its prediction methods. In particular, if one has radiators or scatters, which cannot be expressed by simple geometry, then inverse boundary element method (BEM) is normally employed to reconstruct the sound field induced by sound sources with irregular profiles. The characteristics of boundary element, including the element shape, characteristic length, order of shape function and others, affect the reconstruction error. Investigating the errors by means of changing these factors will provide a guide line for selecting appropriate factors, associated with the elements of BEM. These factors are investigated by numerical simulations, and the accuracies with respect to the variant factors are compared. Novel suggestions for selecting appropriate boundary element factors are described based on the simulation results.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2009.05a
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• pp.177-180
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• 2009

This study investigates the perception of different fabrics by consumers when provided with a video clip with rustling sounds of the fabric. We utilized sportswear products that are currently on the market and evaluated the emotional response of internet shoppers by measuring the physiological and psychological responses. Three kinds of vapor-permeable water-repellent fabric were selected to generate video clips each containing the fabric rustling sound and images of exercise activities wearing the sportswear made of the respective fabric. The new experimental website contained the video clips and was compared with the original website which served as a control. 30 subjects, who had experience to buy clothing online, took part in the physiological and psychological response to the video clip. Electroen-cephalography (EEG) was used to measure the physiological response while the psychological response consisted of evaluating accurate perception of the fabric, satisfaction, and consumer interest. When we offered video clips with fabric's rustling sound on the website, subjects answered they could get more accurate and rapid information to decide to purchase the products than otherwise they do the shopping without such information. However, such rustling sounds somewhat annoy customers, as proved psychological and physiological response. Our study is a critical step in evaluating the consumer's emotional response to sportswear fabric which will promote selling frequency, reduce the return rate and aid development of new sportswear fabric further evolution of the industry.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2008.04a
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• pp.272-275
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• 2008

In case a middle school music room locating in Iksan City, this space had been finished its construction work with the indiscreet sound-absorbing materials despite the music lesson is taught thereat. Accordingly, when music lesson since it sounds aridly due to insufficiency of echo and sound-volume feeling in music appreciation or music performance sound, there is some difficulty in the music lesson. For the purpose to control the obstructive factors owing to such short Reverberation Time, it optimizes the acoustic factor using Acoustic Simulation after arrangement of Acoustic Design, it has conducted a Psycho-acoustics Experiment using the Auralizational Technique that can experience the Virtual Acoustic Field at its designing stage. As the result of investigation about the acoustic satisfaction on the relevant subject space and the satisfaction with regard to the pertinent each items, it was known that the valuation on acoustic performance was evidently improved at 'after-reformation' than 'before-reformation'. It is considered that such material could be utilized as the useful material that can improve the architectural acoustic factor when construction and renovation of any middle school music room in the future.