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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 33, Issue 6 - Nov 2014
Volume 33, Issue 5 - Sep 2014
Volume 33, Issue 4 - Jul 2014
Volume 33, Issue 3 - May 2014
Volume 33, Issue 2 - Mar 2014
Volume 33, Issue 1 - Jan 2014
Selecting the target year
Acoustic Target of Interest Tracking Algorithm Using Classification Feedback
Choi, Kiseok ;
The Journal of the Acoustical Society of Korea, volume 33, issue 4, 2014, Pages 225~231
DOI : 10.7776/ASK.2014.33.4.225
This paper suggests an algorithm to improve the tracking performance for an underwater acoustic target using the feedback information of acoustic feature of a target. While conventional tracking algorithms use detected acoustic signals only, the proposed algorithm uses detected acoustic signals and target feature information as well. Since the proposed algorithm tracks only the selected measurements using target feature information, it prevents onset of unnecessary tracks and improves tracking performance for target of interest. Furthermore, it optimizes tracking parameters for the target of interest and guarantees robustness and consistency of the track. Some simulations are performed to demonstrate the improved tracking performance of the proposed algorithm.
Approximation of a Warship Passive Sonar Signal Using Taylor Expansion
Hong, Wooyoung ; Jung, Youngcheol ; Lim, Jun-Seok ; Seong, Woojae ;
The Journal of the Acoustical Society of Korea, volume 33, issue 4, 2014, Pages 232~237
DOI : 10.7776/ASK.2014.33.4.232
A passive sonar of warship is composed of several directional or omni-directional sensors. In order to model the acoustic signal received into a warship sonar, the wave propagation modeling is usually required from arbitrary noise source to all sensors equipped to the sonar. However, the full calculation for all sensors is time-consuming and the performance of sonar simulator deteriorates. In this study, we suggest an asymptotic method to estimate the sonar signal arrived to sensors adjacent to the reference sensor, where it is assumed that all information of eigenrays is known. This method is developed using Taylor series for the time delay of eigenray and similar to Fraunhofer and Fresnel approximation for sonar aperture. To validate the proposed method, some numerical experiments are performed for the passive sonar. The approximation when the second-order term is kept is vastly superior. In addition, the error criterion for each approximation is provided with a practical example.
Theoretical Analysis on the Array Microphone Measurement for Noise from Rails
Ryue, Jungsoo ; Jang, Seungho ; Kwon, Hyu-Sang ;
The Journal of the Acoustical Society of Korea, volume 33, issue 4, 2014, Pages 238~247
DOI : 10.7776/ASK.2014.33.4.238
In this paper, rail vibration and its sound radiation are investigated, then the rail noise measurement by using microphone array is explored theoretically. A concrete slab track for domestic high speed trains is modeled as a Timoshenko beam on elastic support, regarding the moving of the excitation force on the rail. From the radiation characteristics of rail noise generated by a line source, the effect of moving load on sound radiation is obtained. Also it is found that the beam angle of the microphone array is a prominent factor to measure the rail noise level reliably because the rail noise propagates as a plane wave. In this investigation, a proper beam angle for the rail noise measurement by microphone array is suggested.
Frequency-Cepstral Features for Bag of Words Based Acoustic Context Awareness
Park, Sang-Wook ; Choi, Woo-Hyun ; Ko, Hanseok ;
The Journal of the Acoustical Society of Korea, volume 33, issue 4, 2014, Pages 248~254
DOI : 10.7776/ASK.2014.33.4.248
Among acoustic signal analysis tasks, acoustic context awareness is one of the most formidable tasks in terms of complexity since it requires sophisticated understanding of individual acoustic events. In conventional context awareness methods, individual acoustic event detection or recognition is employed to generate a relevant decision on the impending context. However this approach may produce poorly performing decision results in practical situations due to the possibility of events occurring simultaneously or the acoustically similar events that are difficult to distinguish with each other. Particularly, the babble noise acoustic event occurring at a bus or subway environment may create confusion to context awareness task since babbling is similar in any environment. Therefore in this paper, a frequency-cepstral feature vector is proposed to mitigate the confusion problem during the situation awareness task of binary decisions: bus or metro. By employing the Support Vector Machine (SVM) as the classifier, the proposed feature vector scheme is shown to produce better performance than the conventional scheme.
Underwater Acoustic Communication Using Nonlinear Chirp Signal
Lee, Chang-Eun ; Kim, Ki-Man ; Kim, Woo-Sik ; Chun, Seung-Yong ; Lee, Sang-Kook ;
The Journal of the Acoustical Society of Korea, volume 33, issue 4, 2014, Pages 255~261
DOI : 10.7776/ASK.2014.33.4.255
This paper presents an underwater acoustic communication with nonlinear chirp modulation. The information is carried by the carrier amplitude, frequency or phase in the most common underwater acoustic communications. However, the proposed method includes the information within frequency variation of carrier wave for a symbol. Especially, as carrier wave the hyperbolic frequency modulated signal, one of the nonlinear chirp signal, is used and it is robust in the Doppler channel. The proposed method was analyzed and compared to conventional method by simulation. When the doppler shift existed, the error probability of the proposed method is reduced by 5~12 % than conventional method with linear frequency modulated signal. Sea trial was performed to analyze the performance of the proposed method.
Efficient Partitioning of Matched Filter for Long Pulse in Active Sonar Application
Shin, Donghoon ; Kim, Jin Seok ;
The Journal of the Acoustical Society of Korea, volume 33, issue 4, 2014, Pages 262~267
DOI : 10.7776/ASK.2014.33.4.262
Recently, long pulses are transmitted for target detection in active sonar application. Matched filtering implemented by simple convolution algorithm, requires massive computational power for long replica. The computational loads are reduced significantly by implementing the convolution in the frequency domain with overlap add method, but the performance degrades for specified input/output system delay which constrains the size of FFT function. For performance improvement, the replica could be partitioned into uniform blocks (FDL) by re-using IFFT operations, or variable blocks of increasing length (MC) by using the largest possible blocks to calculate the convolution. In this paper, by combining the strong points of the two methods, we propose a new filter partition structure that allows for further optimization of the previous two methods.
Speech Recognition Using MSVQ/TDRNN
Kim, Sung-Suk ;
The Journal of the Acoustical Society of Korea, volume 33, issue 4, 2014, Pages 268~272
DOI : 10.7776/ASK.2014.33.4.268
This paper presents a method for speech recognition using multi-section vector-quantization (MSVQ) and time-delay recurrent neural network (TDTNN). The MSVQ generates the codebook with normalized uniform sections of voice signal, and the TDRNN performs the speech recognition using the MSVQ codebook. The TDRNN is a time-delay recurrent neural network classifier with two different representations of dynamic context: the time-delayed input nodes represent local dynamic context, while the recursive nodes are able to represent long-term dynamic context of voice signal. The cepstral PLP coefficients were used as speech features. In the speech recognition experiments, the MSVQ/TDRNN speech recognizer shows 97.9 % word recognition rate for speaker independent recognition.