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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
Editor in Chief :
Volume & Issues
Volume 15, Issue 6 - Dec 1996
Volume 15, Issue 5 - Oct 1996
Volume 15, Issue 4 - Aug 1996
Volume 15, Issue 2 - Apr 1996
Volume 15, Issue 1 - Feb 1996
Volume 15, Issue 4E - 00 1996
Volume 15, Issue 3E - 00 1996
Volume 15, Issue 2E - 00 1996
Volume 15, Issue 1E - 00 1996
Selecting the target year
The Study of a Correlation between Characteristics of Violin Vibrato and Musical Factors
Choi, Eun-Kyu ; Sung, Koeng-Mo ; Suh, Woo-Suk ;
The Journal of the Acoustical Society of Korea, volume 15, issue 1, 1996, Pages 5~9
Vibrato means periodic variations of various characteristics in sound wave. Because it causes special tonal effects, it plays and important role in musical performance. But when we examine the cases of scientific study about the vibrato that has been done until now, the cases were focused just on acoustic analysis of vibrato, so they didn't disclose the correlation between the results of analysis and the musical factors concerning actual performance. So this paper attempts to analyze violin vibrato acoustically, and find out the interrelation between the results and the various musical factors of violin performance.
Development of an Ultrasonic Motor and Evaluation Device
Sin, Seong-Su ; Ryu, Yeong-Su ; Kim, Yu-Man ;
The Journal of the Acoustical Society of Korea, volume 15, issue 1, 1996, Pages 10~16
Ultrasonic motor is a motor driven by the stator via frictional contact forces generated from ultrasonic vibration of piezoelectric elements. In order to control the ultrasonic motor, it is essential to measure accurately the motor characteristics with respect to driving parameters such as frequency, voltage, phase difference and duty ratio of the driving signals. In this paper, a PC-interfaced evaluation device is developed, and the characteristic curves of the fabricated ultrasonic motor are measured with those parameters. All driving parameters are processed digitally. The developed evaluation device can facilitate charateristics measurements effectively, and provide a base for digital control of the ultrasonic motor.
A Prediction of Radiation Power for the Planar Array Acoustic Transducer Considering Mutual Coupling Effects
Lee, Jong-Kil ; Seo, In-Chang ;
The Journal of the Acoustical Society of Korea, volume 15, issue 1, 1996, Pages 17~22
Planar array of acoustic transducer is normally used in a sonar system. Acoustic radiation makes beam pattern in underwater uses. The main source of the beam pattern is due to the transducer array. Therefore, estimation of the acoustic radiated power is necessary to predict the performance and efficiency of the transducer. As an example of the acoustic radiation power, nine acoustic transducers mounted to a rigid infinite baffle are considered in a theoretical model. Each piston's acoustic radiation consists of self- and mutual-radiation impedances. Total radiation impedances and acoustic radiation power of the transducers are extracted using on the theory of an equivalent electric circuit. The theoretical results reveal that acoustic radiation power of the transducer depends on the mutual coupling effects
Extended Principal Domain for Discrete Frequency-Domain Quadratic Volterra Models
Im, Sung-Bin ; Lee, Won-Chul ; Bae, Myung-Jin ;
The Journal of the Acoustical Society of Korea, volume 15, issue 1, 1996, Pages 23~33
In this paper we point out that if the classical principal domain for bispectra is utilized to determine a second-order Volterra model's output, such and output will be incomplete. This deficiency is associated with the periodic nature of the DFT. For this reason, the objective of this paper is to present an "extended" principal domain for Volterra kernels which leads to an improved estimate of the nonlinear system's response. In order to define the extended principal domain, we derive a new discrete frequency-domain Volterra model from a discrete time-domain Volterra model utilizing 2-dimensional DFT and the relationship between the quadratic component of the Volterra model and a square filter. The effect of the extended domain on the model output is interpreted in terms of the periodicity of DFT. Through computer simulations, we demonstrate the effects of the extended principal domain on the Volterra modeling. The simulation results indicate that the extended principal domain plays and important role in computing Volterra model outputs and estimating Volterra model coefficients.
An Enhanced Target State Estimation using Covariance Analysis Techniques for a Monopulse Sonar System
Lee, Chang-Ho ; Kim, Jea-Soo ; Lee, Sang-Young ; Kim, Kang ; Oh, Woun-Chun ; Cho, Woon-Hyun ;
The Journal of the Acoustical Society of Korea, volume 15, issue 1, 1996, Pages 34~39
Target state estimation is a fundamental problem of the sonar signal processing. In this paper, the covariance analysis techniques are applied to enhance the performance of the target state estimation of a monopulse sonar system. MOST, the artificial target signal generator based on the highlight model is used to generate signals in various target states. The performance of the developed method has been evaluated by applying it to the various S/N. The enhanced performance of the covariance analysis method presented in this paper is discussed.
Optimal Beam Design of Underwater Acoustic Planar Array Transducer Considering Radiation Impedance
Joh, Chee-Young ; Seo, Hee-Seon ; Lee, Jeong-Min ;
The Journal of the Acoustical Society of Korea, volume 15, issue 1, 1996, Pages 40~45
In this paper, a nonlinear optimal design technique is presented to find an optimal beam pattern. With this technique, the beam width is minimized with respect to a given maximum allowable side-lobe level considering the self- and mutual radiation impedances of vibrators. The proposed method is applied to design a planar array consisting 37 vibrators which are symmetric in X, Y and
axes. The results show that significantly low side-lobe level maintaining a main beam width can be obtained using this method.
A DCT Adaptive Subband Filter Algorithm Using Wavelet Transform
Kim, Seon-Woong ; Kim, Sung-Hwan ;
The Journal of the Acoustical Society of Korea, volume 15, issue 1, 1996, Pages 46~53
Adaptive LMS algorithm has been used in many application areas due to its low complexity. In this paper input signal is transformed into the subbands with arbitrary bandwidth. In each subbands the dynamic range can be reduced, so that the independent filtering in each subbands has faster convergence rate than the full band system. The DCT transform domain LMS adaptive filtering has the whitening effect of input signal at each bands. This leads the convergence rate to very high speed owing to the decrease of eigen value spread Finally, the filtered signals in each subbands are synthesized for the output signal to have full frequency components. In this procedure wavelet filter bank guarantees the perfect reconstruction of signal without any interspectra interference. In simulation for the case of speech signal added additive white gaussian noise, the suggested algorithm shows better performance than that of conventional NLMS algorithm at high SNR.
A Musical Symbol recognition By Using Graphical Distance Measures
Jun, Jung-Woo ; Jang, Kyung-Shik ; Heo, Gyeong-Yong ; Kim, Jai-Hie ;
The Journal of the Acoustical Society of Korea, volume 15, issue 1, 1996, Pages 54~60
In most pattern recognition and image understanding applications, images are degraded by noise and other distortions. Therefore, it is more relevant to decide how similar two objects are rather than to decide whether the two are exactly the same. In this paper, we propose a method for recognizing degraded symbols using a distance measure between two graphs representing the symbols. a symbol is represented as a graph consisting of nodes and edges based on the run graph concept. The graph is then transformed into a reference model graph with production rule containing the embedding transform. The symbols are recognized by using the distance measure which is estimated by using the number of production rules used and the structural homomorphism between a transformed graph and a model graph. the proposed approach is applies to the recognition of non-note musical symbols and the result are given.
Analysis of Intention in Spoken Dialogue based on Classifying Sentence Patterns
Choi, Hwan-Jin ; Song, Chang-Hwan ; Oh, Yung-Hwan ;
The Journal of the Acoustical Society of Korea, volume 15, issue 1, 1996, Pages 61~70
According to topics or speaker's intentions in a dialogue, utterance spoken by speaker has a different sentence structure of word combinations. Based on these facts, we have proposed the statistical approach. IDT(intention decision table), which is modeling the correlations between sentence patterns and the intention. In a IDT, the sentence is splitted into 5 different factors, and the intention of a sentence is determined by the similarity between and intention and 5 factors that have represent a sentence. From the experimental results, the IDT has indicated that the prediction rate of an intention is improved 10~18% over the word-intention correlations and is enhanced 3~12% compared with the MIG(Markov intention graph) that models the intention with a transition graph for word categories in a sentence. Based on these facts, we have found that the IDT is effective method for the prediction of an intention.
Directional Characteristics of Sleeve-gun Arrays in Marine Seismic Survey
Yoo, Hai-Soo ; Yang, Sung-Jin ;
The Journal of the Acoustical Society of Korea, volume 15, issue 1, 1996, Pages 71~80
Characteristics of sleeve-gun arrays installed on the R/V Onnuri were analyzed and compared with survey data. In the case of cluster array, the beam width in the frequency range up to 814Hz is constant as
, and rapidly narrows in the frequency range of 814-1631Hz. However, in the case of long and wide arrays, as the frequency increases, the beamwidth decreases. The optimal frequency is 69Hz. the main lobe of vertical inclination has its maximum amplitude at phase angle
. The optimal frequency of cluster array which produces little side lobe is less than 1631Hz, and those of long and wide arrays are less than 108Hz. As a result, the cluster array produces a good source for high-resolution seismic survey, while the long and wide arrays are suitable for the survey of deep structures. The final high-resolution seismic section with cluster array was compared with that of long and wide arrays.
A Software Package Development for Loudspeaker Performance Evaluation
Choi, Yeong-Ha ; Myung, Hyung-Gook ; Sung, Koeng-Mo ;
The Journal of the Acoustical Society of Korea, volume 15, issue 1, 1996, Pages 81~86
Some investigations have been made to evaluate the sound quality of a loudspeaker system, objectively and accurately. Also, an algorithm is proposed to predict the various subjective values regarding loudspeaker performance based on the frequency response measured in anechoic chamber. A PC-based software that processes the proposed algorithm has also been developed. To verify the validity of the developed software, three loudspeakers has been evaluated using it and the evaluation results have been compared with the results of the listening test. The comparison between the two showed a good similarity.
Feature Vector Extraction Method for Transient Sonar Signals Using PR-QMF Wavelet Transform
Jung, Yong-Min ; Choi, Jong-Ho ; Cho, Yong-Soo ; Oh, Won-Tcheon ;
The Journal of the Acoustical Society of Korea, volume 15, issue 1, 1996, Pages 87~92
Transient signals in underwater show several characterisrics, that is, short duration, strong nonstationarity, various types of transient sources, which make it difficult to analyze and classify transient signals. In this paper, the feature vector extraction method for transient SOMAR signals is discussed by applying digital signal processing methods to the analysis of transient signals. A feature vector extraction methods using wavelet transform, which enable us to obtain better recognition rate than automatic classification using the classical method, are proposed. It is confirmed by simulation that the proposed method using wavelet transform performs better than the classical method even with smaller number of feature vectors. Especially, the feature vector extraction method using PR-QMF wavelet transform with the Daubechies coefficients is shown to perform well in noisy environment with easy implementation.
Implementation and Performance Evaluation of the System for Speech Services using VMEbus
Kwon, Oh-Il ; Kang, Kyung-Young ; Kim, Tong-Ha ; Rhee, Tae-Won ;
The Journal of the Acoustical Society of Korea, volume 15, issue 1, 1996, Pages 93~101
In this paper, we implement the system for speech processing to provide the subscribers who are using the telephone network with better speech services. We develop the specified board which is processing speech signal and devise the system which carries out storing and replaying the speech signal under the condition that one master board controls multiple DSP(Digital Signal Processing) boards using VME bus. We use CPU30 board as a maste board and develop SPM(Signal Processing Module) board as a DSP board and then evaluate performance of the system.