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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
The Journal of the Acoustical Society of Korea
Journal Basic Information
Journal DOI :
The Acoustical Society of Korea
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Volume & Issues
Volume 25, Issue 8 - Nov 2006
Volume 25, Issue 7 - Oct 2006
Volume 25, Issue 6 - Aug 2006
Volume 25, Issue 5 - Jul 2006
Volume 25, Issue 2E - Jun 2006
Volume 25, Issue 4 - May 2006
Volume 25, Issue 3 - Apr 2006
Volume 25, Issue 2 - Feb 2006
Volume 25, Issue 1 - Jan 2006
Selecting the target year
Analysis of Vibration in Cello Bridge
Choi Gi-Sang ;
The Journal of the Acoustical Society of Korea, volume 25, issue 5, 2006, Pages 197~206
Vibration of string is transmitted to the front plate through bridge to cause resonance of the instrument body in viol family string instruments. Therefore. the properties. geometrical shape. and positioning of the bridge are expected to have some effect on the sound color. In this study the strain and the stress in the bridge. and the force exerted on the top plate by the bridge as the string vibrates the bridge in cello are calculated through simulation based on the theory of elasticity. The modes of vibration and the characteristic frequencies are also found. Furthermore. the effect of geometric shape of bridge on sound color is studied in terms of frequency response. The results of this study show that the vibration characteristics of bridge is quite complex and the properties and the geometrical shape of bridge have significant effect on sound color, and therefore. the sound color of a cello can be controlled by changing the geometrical shape of bridge.
The Effect of Auditory Condition on Voice Parameter of Teacher
Lee Ju-Young ; Baek Kwang-Hyun ;
The Journal of the Acoustical Society of Korea, volume 25, issue 5, 2006, Pages 207~212
The purpose of this study was to compare voice parameters in auditory conditions (normal/noise/music) between a teacher group and a control group. Results of statistical analysis showed that the teacher group had higher jitter (%) and shimmer (%) values than the control group. It indicated that the teacher group had larger variations in pitch and dynamic of their voice. In the teacher group, the voice under noisy condition showed a higher value of fundamental frequency than that under normal condition. though its fundamental frequency did not show any significant difference between the noisy condition and the musical condition. In the control group, however, although the voice under noisy condition also showed a higher value of fundamental frequency than that under normal condition, its fundamental frequency was significantly different between the noisy condition and the musical condition.
The Error Pattern Analysis of the HMM-Based Automatic Phoneme Segmentation
Kim Min-Je ; Lee Jung-Chul ; Kim Jong-Jin ;
The Journal of the Acoustical Society of Korea, volume 25, issue 5, 2006, Pages 213~221
Phone segmentation of speech waveform is especially important for concatenative text to speech synthesis which uses segmented corpora for the construction of synthetic units. because the quality of synthesized speech depends critically on the accuracy of the segmentation. In the beginning. the phone segmentation was manually performed. but it brings the huge effort and the large time delay. HMM-based approaches adopted from automatic speech recognition are most widely used for automatic segmentation in speech synthesis, providing a consistent and accurate phone labeling scheme. Even the HMM-based approach has been successful, it may locate a phone boundary at a different position than expected. In this paper. we categorized adjacent phoneme pairs and analyzed the mismatches between hand-labeled transcriptions and HMM-based labels. Then we described the dominant error patterns that must be improved for the speech synthesis. For the experiment. hand labeled standard Korean speech DB from ETRI was used as a reference DB. Time difference larger than 20ms between hand-labeled phoneme boundary and auto-aligned boundary is treated as an automatic segmentation error. Our experimental results from female speaker revealed that plosive-vowel, affricate-vowel and vowel-liquid pairs showed high accuracies, 99%, 99.5% and 99% respectively. But stop-nasal, stop-liquid and nasal-liquid pairs showed very low accuracies, 45%, 50% and 55%. And these from male speaker revealed similar tendency.
Studying Acoustical Properties of Micro-Speaker as a Function of Diaphragm Material
Oh Sei-Jin ;
The Journal of the Acoustical Society of Korea, volume 25, issue 5, 2006, Pages 222~228
The acoustical property of micro-speaker had been investigated as a function of the diaphragm material in this study. Young's modulus and the density of material is deeply related to the determination of sound velocity and stiffness. As a result, it was appeared that the resonance frequency of micro-speaker was PEI < PPS < PET < PEN. This experimental result was in an excellent agreement with the theoretical one. The increasing ratio of sound pressure level to the frequency between 20Hz and the resonance frequency (
) and the high resonance frequency (
) were not affected by the diaphragm material.
Analytic Error Caused by the Inconsistency of the Approximation Order between the Non Local Boundary Condition and the Parabolic Governing Equation
Lee Keun-Hwa ; Seong Woo-Jae ;
The Journal of the Acoustical Society of Korea, volume 25, issue 5, 2006, Pages 229~238
This paper shows the analytic error caused by the inconsistency of the approximation order between the non local boundary condition (NLBC) and the parabolic governing equation. To obtain the analytic error, we first transform the NLBC to the half space domain using plane wave analysis. Then, the analytic error is derived on the boundary between the true numerical domain and the half space domain equivalent to the NLBC. The derived analytic error is physically expressed as the artificial reflection. We examine the characteristic of the analytic error for the grazing angle, the approximation order of the PE or the NLBC. Our main contribution is to present the analytic method of error estimation and the application limit for the high order parabolic equation and the NLBC.
Theoretical Development and Experimental Investigation of Underwater Acoustic Communication for Multiple Receiving Locations Based on the Adaptive Time-Reversal Processing
Shin Kee-Cheol ; Byun Yang-Hun ; Kim Jea-Soo ;
The Journal of the Acoustical Society of Korea, volume 25, issue 5, 2006, Pages 239~245
Time-reversal processing (TRP) has been shown as an effective way to focus in both time and space. The temporal focusing properties have been used extensively in underwater acoustics communications. Recently. adaptive time-reversal processing (ATRP) was applied to the simultaneous multiple focusing in an ocean waveguide. In this study. multiple focusing with ATRP is extended to the underwater acoustic communication algorithm for multiple receiving locations. The developed algorithm is applied to the underwater acoustic communication to show, via simulation and real data, that the simultaneous self-equalization at multiple receiving locations is achieved.
Measurement of the Plane Wave Reflection Coefficient for the Saturated Granular Medium in the Water Tank and Comparison to Predictions by the Biot Theory
Lee Keun-Hwa ;
The Journal of the Acoustical Society of Korea, volume 25, issue 5, 2006, Pages 246~256
The plane wave reflection coefficient is an acoustic property containing all the information concerning the ocean bottom and can be used as an input parameter to various acoustic propagation models. In this paper, we measure the plane wave reflection coefficient, the sound speed, thd the attenuation for saturated granular medium in the water tank. Three kinds of glass beads and natural sand are used as the granular medium. The reflection experiment is performed with the sinusoidal tone bursts of 100 kHz at incident angles from 28 to 53 degrees, and the sound speed and attenuation experiment are performed also with the same signal. From the measured reflection signal, the reflection coefficient is calculated with the self calibration method and the experimental uncertainties are discussed. The sound speed and the attenuation measurements are used for the estimation of the porosity and permeability, the main Biot parameters. The estimated values are compared to the directly measured values and used as input values to the Biot theory in order to calculate the theoretical reflection coefficient. Finally, the reflection coefficient predicted by Biot theory is compared to the measured reflection coefficient and their characteristics are discussed.