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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The Journal of the Acoustical Society of Korea
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Journal DOI :
The Acoustical Society of Korea
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Volume & Issues
Volume 28, Issue 8 - Nov 2009
Volume 28, Issue 7 - Oct 2009
Volume 28, Issue 6 - Aug 2009
Volume 28, Issue 5 - Jul 2009
Volume 28, Issue 4 - May 2009
Volume 28, Issue 3 - Apr 2009
Volume 28, Issue 2 - Feb 2009
Volume 28, Issue 1 - Jan 2009
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On the Principles and Applications of Wave Field Synthesis
Yoo, Jae-Hyoun ; Shim, Hwan ; Chung, Hyun-Joo ; Sung, Koeng-Mo ; Kang, Kyeong-Ok ;
The Journal of the Acoustical Society of Korea, volume 28, issue 8, 2009, Pages 688~696
There are many studies on Wave Field Synthesis(WFS) which provides better presence and spaciousness than conventional discrete multichannel audio reproduction methods. However, it has several problems such as the listener-enclosing loudspeaker array and pre-authorized object-based source signal, so it is not widely used except in large-scale listening rooms. This paper presents a method which utilizes the merit of WFS in small listening rooms such as a living room.
Blind Rhythmic Source Separation
Kim, Min-Je ; Yoo, Ji-Ho ; Kang, Kyeong-Ok ; Choi, Seung-Jin ;
The Journal of the Acoustical Society of Korea, volume 28, issue 8, 2009, Pages 697~705
An unsupervised (blind) method is proposed aiming at extracting rhythmic sources from commercial polyphonic music whose number of channels is limited to one. Commercial music signals are not usually provided with more than two channels while they often contain multiple instruments including singing voice. Therefore, instead of using conventional modeling of mixing environments or statistical characteristics, we should introduce other source-specific characteristics for separating or extracting sources in the under determined environments. In this paper, we concentrate on extracting rhythmic sources from the mixture with the other harmonic sources. An extension of nonnegative matrix factorization (NMF), which is called nonnegative matrix partial co-factorization (NMPCF), is used to analyze multiple relationships between spectral and temporal properties in the given input matrices. Moreover, temporal repeatability of the rhythmic sound sources is implicated as a common rhythmic property among segments of an input mixture signal. The proposed method shows acceptable, but not superior separation quality to referred prior knowledge-based drum source separation systems, but it has better applicability due to its blind manner in separation, for example, when there is no prior information or the target rhythmic source is irregular.
Overview of MPEG-A Interactive Music Application Format
Jang, In-Seon ; Seo, Jeong-Il ; Kang, Kyeong-Ok ;
The Journal of the Acoustical Society of Korea, volume 28, issue 8, 2009, Pages 706~713
Standardization of technology for formatting multiple audio tracks and relevant information for interactive music service is in progress owing to the increasing need of consumers for participating in music production to their own taste. In this paper, we introduce the status of MPEG-A Interactive Music Application Format (IM AF) standardization and analyze techniques adopted in the current IM AF.
Sound Source Externalization Algorithm Using Modified HRTFs and an Acoustic Simulation Method
Lee, Yong-Ju ; Jang, Dae-Young ; Jang, In-Seon ; Kang, Kyeong-Ok ;
The Journal of the Acoustical Society of Korea, volume 28, issue 8, 2009, Pages 714~722
This paper presents a new sound source externalization algorithm for increasing spaciousness and presence on earphone or headphone environments. To do this, we used modified head related transfer functions (M-HRTFs) and room impulse responses acquired by an acoustic simulation method. M-HRTFs developed by ETRI have less tone color distortion of original sound sources than traditional HRTFs. The acoustic simulation method is used to obtain more natural reflected sound. To verify the proposed externalization algorithm, we performed a listening test. From the test, the proposed algorithm is effective in externalizing the sound sources especially when they are on the left and right sides.
Sound Field Reconstruction Technology Using a Three Dimensional Loudspeaker Array
Seo, Jeong-Il ; Kang, Kyeong-Ok ; Fazi, Filippo M. ; Nelson, Philip A. ;
The Journal of the Acoustical Society of Korea, volume 28, issue 8, 2009, Pages 723~731
In this paper, we propose a novel sound field reconstruction algorithm using a three dimensional loudspeaker array for providing realistic sound field to multiple listeners. The proposed algorithm is based on minimization of the squared error between the original sound field and the reconstructed sound field by the loudspeaker array over a predefined three dimensional region of the space using a loudspeaker array surrounding the listening area. For evaluating the proposed algorithm, we constructed the three dimensional array composed of 40 loudspeakers and discuss the relevant experiment results.
Manufacture of Flow Phantom with Stenosis and Imaging Evaluation of Power Doppler
Park, Hee-Young ; Bae, Jong-Rim ; Kim, Jeong-Koo ;
The Journal of the Acoustical Society of Korea, volume 28, issue 8, 2009, Pages 732~739
Flow phantom with stenosis was manufactured using an auto-injector to obtain angiostenotic flow information and quality assurance (QA) for ultrasound diagnostic instrumentation. Effectiveness of manufactured flow phantom with stenosis was investigated with power Doppler that was known to have diagnostic efficiency for angiostenosis. The flow phantom with stenosis was manufactured to 70% stenosis with 8 mm and 2.4 mm silicon tube, and silicone tube was covered with gelatin that has acoustic characteristics similar to soft tissue. When the linear transducer was used for measurement, the estimated diameter of normal vessel was measured lower than that of normal value, and the estimated diameter of stenosed vessel was measured higher than that of normal value. The measured parameters were not affected except for the radical conditions such as gain of 60%, PRF of 3000 Hz, use of maximal filter or angle. In addition, when the convex transducer was used for measurement, measurement parameters were affected by gain, PRF, filter, and angle. Therefore it is expected that flow phantom with stenosis manufactured with an auto-injector will be utilized effectively for QA of angiostenotic diagnosis.
Mid Frequency Band Reverberation Model Development Using Ray Theory and Comparison with Experimental Data
Chu, Young-Min ; Seong, Woo-Jae ; Yang, In-Sik ; Oh, Won-Tchon ;
The Journal of the Acoustical Society of Korea, volume 28, issue 8, 2009, Pages 740~754
Sound in the ocean is scattered by inhomogeneities of many different kinds, such as the sea surface, the sea bottom, or the randomly distributed bubble layer and school of fish. The total sum of the scattered signals from these scatterers is called reverberation. In order to simulate the reverberation signal precisely, combination of a propagation model with proper scattering models, corresponding to each scattering mechanism, is required. In this article, we develop a reverberation model based on the ray theory easily combined with the existing scattering models. Developed reverberation model uses (1) Chapman-Harris empirical formula and APL-UW model/SSA model for the sea surface scattering. For the sea bottom scattering, it uses (2) Lambert's law and APL-UW model/SSA model. To verify our developed reverberation model, we compare our results with those in Ellis' article and 2006 reverberation workshop. This verified reverberation model SNURM is used to simulate reverberation signal for the neighboring seas of South Korea at mid frequency and the results from model are compared with experimental data in time domain. Through comparison between experiment data and model results, the features of reverberation signal dependent on environment of each sea is investigated and this analysis leads us to select an appropriate scattering function for each area of interest.
Application of LFM Reverberation Suppression Using Difference of Singular Values in the Underwater Obstacle Detection
Lee, Hyung-Soo ; Kwon, Bum-Soo ; Cho, Chom-Gun ; Lee, Kyun-Kyung ;
The Journal of the Acoustical Society of Korea, volume 28, issue 8, 2009, Pages 755~760
In this paper, we apply a reverberation suppression method using difference of singular values to improve the short-distance underwater obstacle detection probability in reverberation environment induced by a linear frequency modulation signal. The reverberation suppression method using difference of singular values suppresses LFM reverberation based on subtracting the singular values for a reference beam, assumed to contain only the reverberation, from those for the current beam of interest, assumed to contain the reverberation and target echo. For the validation, the reverberation suppression method using difference of singular values is applied to real oceanic data, which are acquired using the cross type array.
Four Segmentalized CBD Method Using Maximum Contrast Value to Improve Detection in the Presence of Reverberation
Choi, Jun-Hyeok ; Yoon, Kyung-Sik ; Lee, Soo-Hyung ; Kwon, Bum-Soo ; Lee, Kyun-Kyung ;
The Journal of the Acoustical Society of Korea, volume 28, issue 8, 2009, Pages 761~767
The detection of target echoes in a sonar image is usually difficult since reverberation is originated by the returns reflected around the boundary and volumes. Under the scenario of the target presence around the reverberation, the detection performance of existing algorithms is degraded. Since they have a similar statistical features. But proposed detector gives improvement existing algorithms Under this scenario. In this paper, 4 segmentation contrast box algorithm using maximum contrast value is proposed based on statistical segmentation, which gives better detection performance in the sense of reducing false alarms. The simulations validate the effectiveness of the proposed algorithm.
A Study on Digital Communication in Air Using Parametric Array
Je, Yub ; Lee, Jae-Il ; Lee, Chong-Hyun ; Moon, Won-Kyu ;
The Journal of the Acoustical Society of Korea, volume 28, issue 8, 2009, Pages 768~773
This paper demonstrates the digital communication in air using the parametric array. The stepped-plate transducer which is suitable for high-power and high-efficient radiation is used to generate the difference frequency wave with the parametric array. The primary frequencies are selected to 83 kHz and 122 kHz and the resulting difference frequency wave at the frequency of 39 kHz is used for the communication. The modulation method is selected to On-Off Keying method. The waveform and signal-to-noise ratio (SNR) is measured and analyzed to see the characteristics of the digital communication using the parametric array. The proper distance for the communication using parametric array is about 3 m. The measured beam width of the 3dB SNR reduction was
. The possibility of the communication in air using the parametric array is confirmed and the high directional characteristic of the communication using the parametric array is expected to have the advantages for the multi path and the security problems.
A Node Grouping Method for Transmission Power Saving in Underwater Acoustic Sensor Network
Hwang, Sung-Ho ; Cho, Ho-Shin ;
The Journal of the Acoustical Society of Korea, volume 28, issue 8, 2009, Pages 774~780
This paper proposes a transmitted power saving method for underwater acoustic sensors considering the acoustic wave propagation characteristic that propagation loss increases more rapidly in higher frequency band. In the proposed scheme, sensor nodes are divided into a few groups based on the distance between sink node and the sensor node, and each group uses its own frequency band. The node group with longer distance uses lower frequency and the node group with shorter distance uses higher frequency. By means of such a distance-dependent frequency allocation, all sensor nodes are able to maintain a certain target signal-to-noise ratio (SNR), but also save transmitted power. In addition, the optimum size of node group is obtained, and also a frequency allocation algorithm is proposed accordingly. Numerical results show that the proposed scheme saves transmitted power by more 10 dB comparing non-grouping methods.
Selection of Scale Model Materials for Acoustical Evaluation of 1:50 Multipurpose Halls
Jeon, Jin-Yong ; Kim, Jeong-Jun ; Kim, Yong-Hee ;
The Journal of the Acoustical Society of Korea, volume 28, issue 8, 2009, Pages 781~789
The absorption coefficients of the materials used in a 1:50 scale model multipurpose hall were measured based on ISO 354 and related laws. The shape and materials for the scale model were evaluated based on reflective surfaces, variable acoustic elements and sound-absorbing quality (125Hz-1kHz average) of seats. The measured average absorption coefficients of audience seats, audience and orchestra were 0.64, 0.74 and 0,45, respectively, which were simulated with the combination of wood, absorption materials and foam board. Various mounting methods for absorption curtain and banner were considered according to the installation methods. The average absorption coefficient was measured as 0.42, 0.47 and 0.45 in the conditions of Type A mounting, E mounting with 0.9 m backing air cavity, and Type G mounting which is suspended at the ceiling, respectively. It was confirmed that the absorption coefficient was increased at low frequency by backing air gap. The finishing material of stage house was an absorption material covered with thin fabric, which aimed average absorption coefficient of 0.68 by using fiber glass board. Each part of the real materials was compared with those of 1:50 scale model and it was found that the absorption characteristics of both cases were similar.
The Voice Characteristics of Children with Palatine Tonsil and Adenoid Hypertrophy
Song, Yun-Kyung ;
The Journal of the Acoustical Society of Korea, volume 28, issue 8, 2009, Pages 790~795
This study evaluated the voice of 68 normal children and 50 children with palatine tonsil and adenoid hypertrophy with MDVP to examine the hypothesis that their mouth breathing makes the vocal folds dry and this condition contributes to lower the level of voice quality. The results showed that children with palatine tonsil and adenoid hypertrophy had statistically significant elevations in Jitt, RAP, PPQ, Shim and APQ parameters, and had the lower level of voice quality. Therefore, the children with palatine tonsil and adenoid hypertrophy need vocal hygiene education.
Fabrication Studies for PZT Preform Using PIM
Shin, Ho-Yong ; Kim, Jong-Ho ; Jang, Jong-Soo ; Im, Jong-In ;
The Journal of the Acoustical Society of Korea, volume 28, issue 8, 2009, Pages 796~805
In this paper, a fabrication process for PZT preform of 1-3 type piezo-composite were studied using powder injection molding (PIM). The viscosity and the Pressure-Volume-Temperature (PVT) characteristics of the fabricated PZT feedstock were analyzed. The filling patterns, pressure, temperature distributions, and forming defects of the preform were analyzed with 3D TIMON commercial packages during PIM process. Also the fabrication conditions and the delivery system of the preform were optimized during the entire PIM process. Based on the simulated results, the preform having uniform distributions of the PZT rod was fabricated with the PIM process.
Study on Sound Reflection Control using an Active Sound Absorber
Chang, Woo-Suk ; Gweon, Dae-Yong ;
The Journal of the Acoustical Society of Korea, volume 28, issue 8, 2009, Pages 806~814
This paper reviews a study about sound reflection control using an active sound absorber. An active sound absorber includes sound transmitting and receiving piezocomposite sensor layers molded by water tight epoxy, and connected with a feedback controller. The multi-layer sensors and the controller consists a closed feedback loop, whose intrinsic characteristics shows excellent impedance matching performance within specified frequency band, and consequently, minimizes reflection waves. Multilayer sound transmission model is derived based on one dimensional model, and its performance is verified with experiment using a pulse tube setup.
Categorized VSSLMS Algorithm
Kim, Seon-Ho ; Chon, Sang-Bae ; Lim, Jun-Seok ; Sung, Koeng-Mo ;
The Journal of the Acoustical Society of Korea, volume 28, issue 8, 2009, Pages 815~821
Information processing in variable and noisy environments is usually accomplished by means of adaptive filters. Among various adaptive algorithms, Least Mean Square (LMS) has become the most popular for its robustness, good tracking capabilities and simplicity, both in terms of computational load and easiness of implementation. In practical application of the LMS algorithm, the most important key parameter is the Step Size. As is well known, if the Step Size is large, the convergence rate of the algorithm will be rapid, but the steady state mean square error (MSE) will increase. On the other hand, if the Step Size is small, the steady state MSE will be small, but the convergence rate will be slow. Many researches have been proposed to alleviate this drawback by using a variable Step Size. In this paper, a new variable Step Size LMS(VSSLMS) called Categorized VSSLMS (CVSSLMS) is proposed. CVSSLMS updates the Step Size by categorizing the current status of the gradient, hence significantly improves the convergence rate. The performance of the proposed algorithm was verified from the view point of convergence rate, Excessive Mean Square Error(EMSE), and complexity through experiments.
A Study on Possibility of Detection of Insulators' Faults by Analyses of Radiation Noises from Insulators
Park, Kyu-Chil ; Yoon, Jong-Rak ; Lee, Jae-Hun ;
The Journal of the Acoustical Society of Korea, volume 28, issue 8, 2009, Pages 822~831
The porcelain insulators are important devices, that are used to isolate electrically and hold mechanically in the high-voltage power transmission systems. The faults of the insulators induce very serious problems to the power transmission line. In this paper, we introduce techniques for fault detections of insulators by acoustic radiation noises from them. We measured radiation noises from normal state insulators and fault state insulators. The used insulators were two different type porcelain insulators, a cut out switch, two different type line posters, and a lightning arrester. Each results was compared each other in time domain, frequency domain and filter banks' outputs. We found the possibility of detection of insulators' faults and also suggested techniques for fault detections.
A Novel Integration Scheme for Audio Visual Speech Recognition
Pham, Than Trung ; Kim, Jin-Young ; Na, Seung-You ;
The Journal of the Acoustical Society of Korea, volume 28, issue 8, 2009, Pages 832~842
Automatic speech recognition (ASR) has been successfully applied to many real human computer interaction (HCI) applications; however, its performance tends to be significantly decreased under noisy environments. The invention of audio visual speech recognition (AVSR) using an acoustic signal and lip motion has recently attracted more attention due to its noise-robustness characteristic. In this paper, we describe our novel integration scheme for AVSR based on a late integration approach. Firstly, we introduce the robust reliability measurement for audio and visual modalities using model based information and signal based information. The model based sources measure the confusability of vocabulary while the signal is used to estimate the noise level. Secondly, the output probabilities of audio and visual speech recognizers are normalized respectively before applying the final integration step using normalized output space and estimated weights. We evaluate the performance of our proposed method via Korean isolated word recognition system. The experimental results demonstrate the effectiveness and feasibility of our proposed system compared to the conventional systems.