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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
Post-Processing with Frequency Domain Wiener Filter for Blind Source Separation
Park Keun-Soo ; Park Jang-Sik ; Kim Hyun-Tae ; Son Kyung-Sik ;
The Journal of the Acoustical Society of Korea, volume 25, issue 2E, 2006, Pages 36~36
In this paper, a novel post processing using Wiener filtering technique is proposed to p rm further interference reduction in FDICA. Using the proposed method, the target signal components are remained with little attenuation while the interference components are drastically suppressed. The results of experiments show that the proposed method achieves a reduction of the residual crosstalk. Compared to the NLMS method, the proposed method has slightly better separation performance in SIR, and even requires much less computational complexity.
A Recursive Data Least Square Algorithm and Its Channel Equalization Application
Lim Jun-Seok ; Kim Jae-Soo ;
The Journal of the Acoustical Society of Korea, volume 25, issue 2E, 2006, Pages 43~43
Abstract-Using the recursive generalized eigendecomposition method, we develop a recursive form solution to the data least squares (DLS) problem, in which the error is assumed to lie in the data matrix only. Simulations demonstrate that DLS outperforms ordinary least square for certain types of deconvolution problems.
Acoustic and Elastic Properties of the Southeastern Yellow Sea Mud, Korea
Kim Gil-Young ;
The Journal of the Acoustical Society of Korea, volume 25, issue 2E, 2006, Pages 49~49
Compressional wave velocity (Vp), shear wave velocity (Vs), elastic and physical properties, and electrical resistivity for two core sediments obtained from Southeastern Yellow Sea Mud (SEYSM) were measured and computed. The sediments consist of homogeneous mud (mostly silt and clay) with shells and shell fragments. As a result, the mean grain size is uniform (
throughout the core sediments. However, physical properties such as wet bulk density and porosity show slightly increasing and decreasing patterns with depth, compared to the mean grain size. The compressional (about 1475 m/s in average) and shear wave (about 60 m/s in average) velocities with depth accurately reflect the pattern of wet bulk density and porosity. Electrical resistivity is more closely correlated with compressional wave velocity than physical properties. The computed Vp/Vs and Poisson''s ratios are relatively higher (more than 10) and lower (approximately 0.002) than Hamilton''s (1979) data, respectively, suggesting the typical characteristics of soft and fully water-saturated marine sediments. Thus, the Vp/Vs ratio in soft and unconsolidated sediments is not likely sufficient to examine lithology and sediment properties. Relationships between the elastic constant and physical properties are correlated well. The elastic constants (Poisson''s ratio, bulk modulus, shear modulus) given in this paper can be used to characterize soft marine sediments saturated with seawater.
Audio Watermark Design Using Hilbert Transform
Lee Jin-Geol ;
The Journal of the Acoustical Society of Korea, volume 25, issue 2E, 2006, Pages 56~56
A novel audio watermark design using Hilbert transform is proposed, and its superiority of performance over the existing design using the absolute values of the audio signal is demonstrated experimentally with measurements of bit error rate (BER) in correlation based decoder. (Classification No. 3.3)
High-Frequency Bistatic Scattering from a Corrugated Sediment Surface
Cho Hong-Sang ; La Hyoung-Sul ; Yoon Kwan-Seob ; Na Jung-Yul ; Kim Bong-Chae ;
The Journal of the Acoustical Society of Korea, volume 25, issue 2E, 2006, Pages 60~60
High-frequency bistatic scattering measurements from a corrugated surface were made in an acoustic water tank. First the azimuthal scattering pattern was measured from an artificially corrugated surface which has varying impedance. The corrugated surface was installed both transverse to the direction of incident wave and longitudinal to the direction of incident wave. The angle between the corrugated surface and the direction of the incident wave was about
. Second, the scattering strengths were measured from the flat sediment and the corrugated sediment. A critical angle of about
was calculated in the acoustic water tank. The measurements were made at three fixed grazing angles:
(lower than critical angle),
(critical angle), and
(higher than critical angle). The scattering angle and the grazing angle are equal in each measurement. Frequencies were from 50 kHz to 100 kHz with an increment of 1 kHz. The corrugated sediment was made transverse to the direction of the incident wave. The first measurement indicates that the scattering patterns depend on the relations between the corrugated surface and the direction of the incident wave. In the second measurement, the data measured from the flat sediment were compared to the APL-UW model and to the NRL model. The NRL model''s output shows more favorable comparisons than the APL-UW model. In case of the corrugated sediment, the model and the measured data are different because the models used an isotropic wave spectrum of sediment roughness in the scattering calculations. The isotropic wave spectrum consists of
. These constants derived from sediment names or bulk size. The model which used the constants didn''t consider the effect of a corrugated surface. In order to consider a corrugated surface, the constants were varied in the APL-UW model.
Robust Music Identification Using Long-Term Dynamic Modulation Spectrum
Kim Hyoung-Gook ; Eom Ki-Wan ;
The Journal of the Acoustical Society of Korea, volume 25, issue 2E, 2006, Pages 69~69
In this paper, we propose a robust music audio fingerprinting system for automatic music retrieval. The fingerprint feature is extracted from the long-term dynamic modulation spectrum (LDMS) estimation in the perceptual compressed domain. The major advantage of this feature is its significant robustness against severe background noise from the street and cars. Further the fast searching is performed by looking up hash table with 32-bit hash values. The hash value bits are quantized from the logarithmic scale modulation frequency coefficients. Experiments illustrate that the LDMS fingerprint has advantages of high scalability, robustness and small fingerprint size. Moreover, the performance is improved remarkably under the severe recording-noise conditions compared with other power spectrum-based robust fingerprints.
Automatic Emotion Classification of Music Signals Using MDCT-Driven Timbre and Tempo Features
Kim Hyoung-Gook ; Eom Ki-Wan ;
The Journal of the Acoustical Society of Korea, volume 25, issue 2E, 2006, Pages 74~74
This paper proposes an effective method for classifying emotions of the music from its acoustical signals. Two feature sets, timbre and tempo, are directly extracted from the modified discrete cosine transform coefficients (MDCT), which are the output of partial MP3 (MPEG 1 Layer 3) decoder. Our tempo feature extraction method is based on the long-term modulation spectrum analysis. In order to effectively combine these two feature sets with different time resolution in an integrated system, a classifier with two layers based on AdaBoost algorithm is used. In the first layer the MDCT-driven timbre features are employed. By adding the MDCT-driven tempo feature in the second layer, the classification precision is improved dramatically.
Multi-Termination Technique for the Measurement of Characteristic Impedance and Propagation Constant of Sound Absorbing Materials Using an Impedance Tube
Lee Jong-Hwa ; Ih Jeong-Guon ;
The Journal of the Acoustical Society of Korea, volume 25, issue 2E, 2006, Pages 79~79
Acoustic characteristics of a sound absorbing material can be identified, if the characteristic impedance and propagation constants are known, which have generally been determined experimentally. One easy method determining these two essential parameters is to measure the one dimensional wave characteristics in the impedance tube. In th udy, the effects of backing conditions on the impedance tube measurement have been examined using several pairs of generally used end conditions. The results showed that the measured values are similar for most pairs of end conditions: however, it was observed that the measured characteristic impedance for different thickness did not agree well for some pairs. In this work, the multi termination method, using three or more known backing con ns, was suggested to reduce such random errors, which are mostly caused by the test procedure. Employing three terminations as a set, comprised of a rigid end, an end with porous material, and an end with a backing cavity, it was demonstrated that improved measured results could be obtained for an open cell PU foam varying widely with three different thicknesses.
Validation of Free-Vortex Embedded CAA Method for Airfoil Vortex Interaction
Wie Seong-Yong ; Lee Duck-Joo ;
The Journal of the Acoustical Society of Korea, volume 25, issue 2E, 2006, Pages 85~85
Blade-vortex interaction (BVI) is one of the most important phenomena in rotor flow since it causes undesirable intense vibration and noise. Since three dimensional Euler or Navier-Stokes solutions to BVI require very high computational cost, BVI has been approximated by airfoil-vortex interaction (AVI) in chordwise planes. To describe more realistic situations with AVI, three dimensional vortex informations such as position, core size and strength are embedded artificially to Computational Aeroacoustics (CAA) calculation at each computational time step. To implement this requirement, in this paper, a technique called free vortex embedded method was used. And the solution by this method was compared with the solution by conventional method for interaction between freely convected vortex and airfoil. For the application to three dimensional free vortex embedded CAA, two dimensional free vortex embedded CAA method was validated in advance.