Go to the main menu
Skip to content
Go to bottom
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
Editor in Chief :
Volume & Issues
Volume 20, Issue 8 - Nov 2001
Volume 20, Issue 7 - Oct 2001
Volume 20, Issue 6 - Aug 2001
Volume 20, Issue 5 - Jul 2001
Volume 20, Issue 4 - May 2001
Volume 20, Issue 3 - Apr 2001
Volume 20, Issue 2 - Feb 2001
Volume 20, Issue 1 - Jan 2001
Volume 20, Issue 4E - 00 2001
Volume 20, Issue 3E - 00 2001
Volume 20, Issue 2E - 00 2001
Volume 20, Issue 1E - 00 2001
Selecting the target year
Acoustic Characteristics of Wedge-shaped Anechoic Tiles with Different Wedge-apex Angles
The Journal of the Acoustical Society of Korea, volume 20, issue 4, 2001, Pages 5~11
Acoustic characteristics of the wedge-shaped anechoic tiles, used as absorbing lining materials for an anechoic water tank, were investigated for different wedge-apex angles. The anechoic tile base has the dimensions of 400mm x 385mm x 15.5mm. In order to investigate anechoic effect, the wedge-apex angles 30° and 60° were selected by using a ray-tracing method. The reflection loss of the anechoic tiles with and without wedges were experimentally studied at normal incident sound waves in water. In this experiment, the reflection loss of wedge-shaped anechoic tiles with the optimum wedge-apex angle 30° is larger than one with the angle 60° and one without wedges. The experimental results show that the wedge-shaped anechoic tiles with the wedge-apex angle 30°, optimized by using ray-tracing method, turn out better absorbing lining materials of an anechoic water tank.
Performance Analysis and Improvement of Array Shape Estimation for SONAR Systems
The Journal of the Acoustical Society of Korea, volume 20, issue 4, 2001, Pages 12~16
To analyze the performance of array shape estimation techniques using auxiliary sensors, the appropriate number and the positions of auxiliary sensors are investigated. Also, a post-processing technique based on spline interpolation is proposed to improve the performance of array shape estimation. The simulation results showed that when auxiliary sensors are arranged uniformly, the performance of shape estimation is better than other arrangements of auxiliary sensors. Also, the proposed post-processing technique improved the performance of the existing shape estimation method, such as Kalman filter method.
A New Robust Acoustic Crosstalk Cancellation Method with Sum and Difference Filter in 3D Audio System
The Journal of the Acoustical Society of Korea, volume 20, issue 4, 2001, Pages 17~21
There are some methods to enhance the ‘sweet spot’in loudspeaker-based 3D audio systems. Most of them can be only applied to narrow frequency band inherently. In this paper, we introduce the more robust 3D sound reproduction system which has far wider robust bandwidth. The system applies a sum and difference filter to the conventional three loudspeaker-based one.
An Enhancement of Speaker Location System Using the Low-frequency Phase Restoration Algorithm and Its Implementation
The Journal of the Acoustical Society of Korea, volume 20, issue 4, 2001, Pages 22~28
This paper describes the implementation of a robust speaker position location system using the voice signal received by microphone array. To be robust to the reverberation which is the major factor of the performance degradation, low-frequency phase restoration algorithm which eliminates the influence of reverberations using the low-frequency information of the CPSP function is proposed. The implemented real-time system consists of a general purpose DSP (TMS320C31 of Texas instruments), analog part which contains amplifiers and filters, and digital part which is composed of the external memory and 12-bit A/D converter. In the real conference room environment, the implemented system that was constructed by the proposed algorithms showed better performance than the conventional system. The error of the TDOA estimation reduced more than 15 samples.
Design of the LSF Parameter Quantizer for the Wideband Speech Codec
The Journal of the Acoustical Society of Korea, volume 20, issue 4, 2001, Pages 29~34
In this paper, we designed an LSF coefficient quantizer of the wideband speech codec that can produce high quality speech service. For the efficient LSF coefficient quantizer, the interframe correlation was used. Also we separately quantized the LSF coefficients with high and low interframe correlation. Predictive pyramid vector quantizer (PVQ) was used for quantizing the LSF coefficients with high interframe correlation, and PVQ was used for quantizing the LSF coefficients with low interframe correlation. Experiments show that the proposed UF quantizer can quantize LSF information in 40 bits/frame, with an average spectral distortion (SD) of 1 dB and less than 3.87% frames having SD greater than 2 dB.
Speech Recognition Using Linear Discriminant Analysis and Common Vector Extraction
The Journal of the Acoustical Society of Korea, volume 20, issue 4, 2001, Pages 35~41
This paper describes Linear Discriminant Analysis and common vector extraction for speech recognition. Voice signal contains psychological and physiological properties of the speaker as well as dialect differences, acoustical environment effects, and phase differences. For these reasons, the same word spelled out by different speakers can be very different heard. This property of speech signal make it very difficult to extract common properties in the same speech class (word or phoneme). Linear algebra method like BT (Karhunen-Loeve Transformation) is generally used for common properties extraction In the speech signals, but common vector extraction which is suggested by M. Bilginer et at. is used in this paper. The method of M. Bilginer et al. extracts the optimized common vector from the speech signals used for training. And it has 100％ recognition accuracy in the trained data which is used for common vector extraction. In spite of these characteristics, the method has some drawback-we cannot use numbers of speech signal for training and the discriminant information among common vectors is not defined. This paper suggests advanced method which can reduce error rate by maximizing the discriminant information among common vectors. And novel method to normalize the size of common vector also added. The result shows improved performance of algorithm and better recognition accuracy of 2％ than conventional method.
Design and Implementation of the VoiceXML Interpreter for Voice Web-service
The Journal of the Acoustical Society of Korea, volume 20, issue 4, 2001, Pages 42~47
In this paper, we propose an interpreter, which recognizes the VoiceXML markups, verifies the validation of the document, and interprets the VoiceXML documents using DI parser and the generated AST by the parser. The VoiceXML interpreter consists of DI parser and executor, and the DI parser uses recursive descent parsing technology, and the executor uses FIA (Form Interpretation Algorithm) proposed by VXML forum. This system uses the Java language in order to develop the runtime environment for VoiceXML efficiently, thus this system has portability.
Selective Attentive Learning for Fast Speaker Adaptation in Multilayer Perceptron
The Journal of the Acoustical Society of Korea, volume 20, issue 4, 2001, Pages 48~53
In this paper, selectively attentive learning method has been proposed to improve the learning speed of multilayer Perceptron based on the error backpropagation algorithm. Three attention criterions are introduced to effectively determine which set of input patterns is or which portion of network is attended to for effective learning. Such criterions are based on the mean square error function of the output layer and class-selective relevance of the hidden nodes. The acceleration of learning time is achieved by lowering the computational cost per iteration. Effectiveness of the proposed method is demonstrated in a speaker adaptation task of isolated word recognition system. The experimental results show that the proposed selective attention technique can reduce the learning time more than 60% in an average sense.
A Study on the Elastic Wave Velocity of Magnetostrictive Materials
The Journal of the Acoustical Society of Korea, volume 20, issue 4, 2001, Pages 54~61
Magnetostrictive materials have nonlinear elasto-magnetic properties. However the constitutive equations to describe the nonlinear properties are not available, yet. In this study we develope the equation in magnetostrictive materials by use of piezomagnetic constitutive equation which is quasi-linearized. With the wave equation, we determine the propagation velocity inside the magnetostrictive materials when a plane wave propagates along a given magnetic field. Validity of the calculated velocity is verified through comparison with experimental velocity measurement results for the most representative magnetostrictive materials. Terfenol-D.
Analysis of Modulus and Phase of Resonance Scattered Elastic Waves from Cylindrical Fluid Scatterers
The Journal of the Acoustical Society of Korea, volume 20, issue 4, 2001, Pages 62~70
Based on the recently developed resonance scattering theory for elastic waves, a relationship between the stress components, which may be measured using ultrasonic transducers, of partial waves scattered from cylindrical fluid scatterer, cavity, and resonance scatterer has been derived. The computed resonance scattered stresses exhibit frequency behaviors similar to the corresponding scattering coefficients: particularly, abrupt changes in phase by 180°near the resonant frequencies. By studying the behavior of pressure in the fluid scatterer, the physics of the theory has been further understood. Using the method studied and developed in this paper, nondestructive characterization of fluid inclusions in elastic media is expected to become more reliable.
A Study on Shallow Water Propagation Model with 2-layered Sediment
The Journal of the Acoustical Society of Korea, volume 20, issue 4, 2001, Pages 71~80
In order to consider the sediment layer's effect to total acoustic field, we composed a 3 layered fluid model of 2 sediment layers by adding an additional layer to the Pekeris model and found solutions by using Green's function, boundary conditions and Sommerfeld radiation condition. The modes were divided into discrete modes and virtual modes, and confirmed that the characteristic equation to find discrete modes was same as that of Tolstoy and Clay for normal modes. Also, we confirmed that under similar conditions the 3 layered model showed same results as that of Pekeris model. We believe this 3 layered model can be used to study the sediment's effect on the virtual mode of near field.
Measurements of Bistatic Sea Surface Scattering Signals
The Journal of the Acoustical Society of Korea, volume 20, issue 4, 2001, Pages 81~86
126-kHz bistatic sea surface scattering measurements were conducted in the shallow waters off the east coasts of Korea. The range from source to receiver was altered to change the scattering angle at the grazing angles of 38％ and 52％ . Unlike bottom scattering signal, the arrival time and the amplitude of sea surface scattering signals were varied due to the fluctuation of sea surface. The measured forward scattering strengths were compared to model predictions of Kirchhoff approximation and small slope approximation. In overall, the tendency of the scattering strengths showed reasonable agreement among the experimental data, Kirchhoff approximation, and small slope approximation.
Velocity Anisotropy of Unconsolidated Sediment in the Ulleung Basin, East Sea
The Journal of the Acoustical Society of Korea, volume 20, issue 4, 2001, Pages 87~93
Velocity anisotropy of unconsolidated sediments in the Ulleung Basin, East Sea were studied by using 22 piston cores. Velocity anisotropy shows about 0.4 and 1.2％ in the Plain and Slope sediments, respectively. Horizontal velocity is greater than vertical velocity. It is resulted in positive anisotropy. Thus, bedding must be regarded as the principal cause of acoustic anisotropy in the Ulleung Basin sediments. The differences of the value are different from 5 m/s to 18 m/s in the Plain and Slope area, respectively. The relationships between physical properties and velocity anisotropy are clearly grouped. This result suggests that the slope sediments are probably affected by sedimentological (esp. physical properties) changes resulting from diagenesis.
Analysis of Low-frequency Reverberation Inshallow Water
The Journal of the Acoustical Society of Korea, volume 20, issue 4, 2001, Pages 94~100
In October 1997, low-frequency reverberation was measured at an experimental site off the west coast of the Jeju island using the explosive charge, Signals Underwater Sound (SUS). Received signals were separated into the noise, the reflection, and the scattering region, and then were analyzed for the spectral and statistical characteristics of each region. In the analysis of the spectrum we verified that each region had a unique frequency band and statistical characteristics as well. The results of this analysis showed that the real and imaginary portions were shown to be both normal distributions in each frequency bin. The reverberation envelope had a Rayleigh distribution and the phase had a uniform distribution.