• Journal of Sensor Science and Technology
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• v.19 no.6
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• pp.490-496
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• 2010

In this study, in order to overcome the weakness of acoustic field analysis which is generally used for ultrasonic probe performance evaluation, automatic acoustic field measurement system and evaluation parameters were proposed. The comparisons between acoustic field simulation and measured acoustic distribution data of normal and abnormal channels were conducted to evaluate the availability of proposed system and evaluation parameters. First, the impulse response characteristic of sample probe was investigated to classify the normal elements and abnormal elements. And then, normal channels and abnormal channels with abnormal element were chosen. The suggested 12 evaluation parameters were calculated using the acoustic fields of these channels. The availability of proposed automatic acoustic field measurement system and evaluation parameters was confirmed. And the performance evaluation of ultrasonic probe using acoustic field analysis could be easier and faster.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.4 s.121
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• pp.289-297
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• 2007

SAFRS is the system designed to reproduce the harmonic sound into the space according to the environmental factors. Here the harmonic sound means the sound which judged by the subjective tests, and the methods were suggested in the former studies. In this research, SAFRS was applied into the Square of D University to evaluate and verify the effectiveness of the system and a few evaluations were carried out as follows; 1) sound perception, frequency, volume and harmony with the space, 2) images of the square and acoustic environment and 3) acoustic environment with existing sounds, fountain sound, produced sound by SAFRS, and both of them respectively. The results can be summarized as follows; 1) According to the evaluation on acoustic environment, no relationships were shown between the cognition of sounds produced by SAFRS and the frequency or volume, but inverse proportion was shown between the volume and special harmony. 2) As the result of image evaluation. the relationship between space and sound image was shown proportional only except the evaluation on main road at night time, it means that the sound proposal with the visual contents matching with the sounds would be more effective than the proposal of sound only. 3) Results of evaluation on acoustic environment showed that the cognition effect at night time was shown higher than that of day time when only the acoustic element was given and the effect was increased when the visual elements matches with the acoustic elements if both of them were given. It confirmed the harmony between visual and acoustic elements was very important.

• Journal of the Korean Society for Nondestructive Testing
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• v.29 no.6
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• pp.534-549
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• 2009

As the thin film technology has emerged in various fields, adhesion of the film interface becomes an important issue in terms of the longevity and durability of thin film devices. Diverse nondestructive methods utilizing acoustic techniques have been developed to assess the interfacial integrity. As an effective technique based on the ultrasonic wave focusing and the surface acoustic wave(SAW) generation, scanning acoustic microscopy(SAM) has been investigated for adhesion evaluation. Visualization of film microstructures and quantification of adhesion weakness levels by SAW dispersion are the recent achievements of SAM. To overcome the limitations in the theoretical dispersion model only suitable for perfectly elastic and isotropic materials, a new model has been more recently developed in consideration of film anisotropy and viscoelasticity and applied to the adhesion evaluation of polymeric films fabricated on semiconductive wafers.

• International Journal of Naval Architecture and Ocean Engineering
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• v.4 no.4
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• pp.374-385
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• 2012

The indoor noise of a ship is usually determined using the A-weighted sound pressure level. However, in order to better understand this phenomenon, evaluation parameters that more accurately reflect the human sense of hearing are required. To find the level of the satisfaction index of the noise inside a naval vessel such as "Loudness" and "Annoyance", psycho-acoustic evaluation of various sound recordings from the naval vessel was performed in a laboratory. The objective of this paper is to develop a single index of "Loudness" and "Annoyance" for noise inside a naval vessel according to a psycho-acoustic evaluation by using psychological responses such as Noise Rating (NR), Noise Criterion (NC), Room Criterion (RC), Preferred Speech Interference Level (PSIL) and loudness level. Additionally, in order to determine a single index of satisfaction for noise such as "Loudness" and "Annoyance", with respect to a human's sense of hearing, a back-propagation neural network is applied.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2008.04a
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• pp.276-280
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• 2008

Korean Classical Music, as the abbreviated wording for 'Korean Music', is being used as the indicating phraseology for our traditional music that distinguishing from Western Music, the foreign music or foreign-styled popular music. Since such Korean Classical Music has the different acoustic characteristics from Western Music, it needs its own performance space for the special exclusive-use of Korean Classical Music. Likewise, even though the demand for the performance space of special exclusive-use for Korean Classical Music where Korean Classical Music is rendering, is on increasing tendency due to the increase of national concern about traditional culture art, since it is being planned without any concrete standard or method that gratifies the supreme listening condition, it is the real situation that a securement of the satisfying acoustic condition is very difficult, after the completion of construction. On such viewpoint, in order to evaluate the acoustic characteristics of the performance space of special exclusive-use for Korean Classical Music, based on the subjective response which reflects human being's psychological attribute at first, this Study has attempted to extract the proper evaluation vocabulary for appraisement on Korean Classical Music. The abstracted vocabulary in such way would be used significantly for Subjective Response Evaluation in order for the evaluation on the Acoustic Characteristics of the performance space of special exclusive-use for Korean Classical Music.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.222-227
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• 2001

Nonlinear acoustic effect has been considered as an effective tool for the evaluation of material degradation. In this paper, the applicability of nonlinear acoustic effect to the evaluation of degradation of 2.25Cr-1Mo steel is investigated. Firstly, a number of 2.25Cr-1Mo steel samples were heat-treated, and their damage mechanism was examined. Secondly, Ultrasonic nonlinear parameter was measured. Nonlinear acoustic parameter was found to be clearly sensitive to the material degradation.

• Journal of Satellite, Information and Communications
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• v.5 no.1
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• pp.69-74
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• 2010

As a part of development process of the COMS, an acoustic vibration test was performed in order to verify that the COMS is safe from the acoustic loads coming from the Ariane-5ECA launch vehicle when it is launched. In this paper, the acoustic vibration test preparation which was performed during the development of the COMS is explained, and through the evaluation of the test results, it was verified whether the COMS is safe from the acoustic load that the COMS will experience during the launch. Through detail evaluation of the acoustic loads on the solar array, Ka band communication payload antenna and feed, GOCI(Geo-Stationary Ocean Color Imager), MI(Meteorological Imager), it was confirmed that the COMS is safe from the acoustic loads from launch vehicle.

• Journal of Power System Engineering
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• v.15 no.1
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• pp.18-23
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• 2011

Image processing has provided powerful techniques to extract from the acoustic signals the desired information on evaluation for leakage existence, leakage rate, and searching for leakage location, etc. The imagery NDE data available can add additional and significant dimension in nondestructive evaluation(NDE) information and thus for exploiting in applications. To extract such information the use of advanced image processing techniques is much needed. In recent years, there has been much increased use of acoustic signal image processing techniques in acoustic NDE. This approach will increase the efficiency of inspection procedures and reduce inspection time. In this paper we are concerned only with This paper is concerned mainly with the use of advanced image processing techniques in valve leakage detection and advanced image restoration and enhancement methods, which attempt to evaluate promptly by a visualization method the acoustic sources while detecting the valve leakage.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.9 s.90
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• pp.884-890
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• 2004

In this paper, an index for the evaluation of vehicle intake booming noise is developed through a correlation analysis of objective measurement data and subjective evaluation data. First, intake orifice noise is measured at the wide-open test condition. And then, acoustic transfer function between intake orifice noise and interior noise at the steady state condition is estimated. Simultaneously, subjective evaluation was carried out with a ten-scale score by 8 engineers. Next, the correlation analysis between the psycho-acoustic parameters derived from the measured data and the subjective evaluation is performed. The most critical factor was determined and the corresponding index for the intake booming noise is obtained from the multiple factor regression method. At last, the effectiveness of the proposed index is validated.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.336-341
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• 2004

This research investigates the feasibility of ultrasonic microscope for nondestructive assessment of thermal degradation in artificially aged commercial Co-base superalloy, FSX414. This alloy has been used for high temperature structure applications such as stationary gas turbine blade and nozzle chamber in fossil plant. Microstructural change was found that the fine carbides became coarser and spheroidized in matrix as aging time increased. The leaky surface acoustic wave velocity gradually decreases by a maximum of 4.7% with increasing aging time up to 4,000hours. However, the longitudinal wave velocity has a little change. Also, it has a good correlation between leaky surface acoustic wave velocity and Vickers hardness. Consequently, LSAW can be used to examine the degree of degradation in thermally aged Co-base superalloy.