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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 30, Issue 8 - Nov 2011
Volume 30, Issue 7 - Oct 2011
Volume 30, Issue 6 - Aug 2011
Volume 30, Issue 5 - Jul 2011
Volume 30, Issue 4 - May 2011
Volume 30, Issue 3 - Apr 2011
Volume 30, Issue 2 - Feb 2011
Volume 30, Issue 1 - Jan 2011
Selecting the target year
Investigation of the Soundscapes of Jeju Olle Route via Soundwalking
Park, Chan-Jae ; Haan, Chan-Hoon ;
The Journal of the Acoustical Society of Korea, volume 30, issue 8, 2011, Pages 410~420
DOI : 10.7776/ASK.2011.30.8.410
The present study aims to investigate the soundscapes of Jeju olle route through the soundwalking. In order to do this, sound measurements and sound recording were undertaken at 10 points along Jeju olle route. Also, loudness of background sound and figure sound were examined. Subjective surveys were carried out using questionnaire and interviews with 32 tourists and 5 acoustical specialists in order to investigate the loudest sound, most pleasant and unpleasant sound, and impressive sound among 17 natural and artificial sounds. Additionally, laboratory experiments were achieved to evaluates sound that have been recorded at the field using same questionnaire and the results were compared with those of field experiments. As a result, the sound heard most in Jeju olle route is the sea wave sound, wind sound, automobile noise, and human voice. It was revealed that the most pleasant sound consisted of nature sound among them, and that unpleasant sounds are artificial sounds. The results of subjective test denote that unpleasant sound is affected by ratio of artificial sound and nature sound. And this also affects the assessment about the loudness of the sound. Also, it was found that the results of both field test and laboratory test are closely correlated in the evaluation of loudness of sound and unpleasant feeling.
Estimation of Nominal Frequency of Whangjongeum by Acoustical Analysis of Old Pyeongyeongs
Yoo, June-Hee ; Park, Jeong-Woo ; Bae, Dae-Sung ; Kim, Hyung-Jun ; Sung, Keong-Mo ; Noh, Jung-Uk ; Koh, Hyun-Woo ;
The Journal of the Acoustical Society of Korea, volume 30, issue 8, 2011, Pages 421~427
DOI : 10.7776/ASK.2011.30.8.421
This study aimed to figure out the numbers and note distributions and sexagenary cycles of old pyeongyoungs systematically, and estimate the nominal frequency of whangjongeum, the Korean tradition pitch standard. As a total 214 old stones in the National Palace Museum, the National Kukak Center, the Kukak National High School were counted by notes and sexagenaries. The nominal frequencies of 17 old whangjong stones' sounds were categorized by cluster analysis method. Using nominal frequencies of stones according to their sexagenaries and Korean traditional intonation were used to estimate the nominal frequencies of the whangjong. The nominal frequency can be estimated by 22 Keychuk stones as 266.9 Hz, by Cheongyu and Gabja stones as 262.4~262.5 Hz, and by Gabjin, Sowha 12 and Sowha 13 as Estimating by 22 Kyechuk stones which were matched with the records. These results seem to be more reliable, because it is based on the whol samples of old pyeongyoungs, while the former studies have been based on couples of whangjong stones' sounds.
Removal of Heterogeneous Candidates Using Positional Accuracy Based on Levenshtein Distance on Isolated n-best Recognition
Yun, Young-Sun ;
The Journal of the Acoustical Society of Korea, volume 30, issue 8, 2011, Pages 428~435
DOI : 10.7776/ASK.2011.30.8.428
Many isolated word recognition systems may generate irrelevant words for recognition results because they use only acoustic information or small amount of language information. In this paper, I propose word similarity that is used for selecting (or removing) less common words from candidates by applying Levenshtein distance. Word similarity is obtained by using positional accuracy that reflects the frequency information along to character's alignment information. This paper also discusses various improving techniques of selection of disparate words. The methods include different loss values, phone accuracy based on confusion information, weights of candidates by ranking order and partial comparisons. Through experiments, I found that the proposed methods are effective for removing heterogeneous words without loss of performance.
Fabrication of a 2-2 Mode Piezocomposite and Derivation of its Equivalent Properties
Shin, Ho-Seop ; Roh, Yong-Rae ;
The Journal of the Acoustical Society of Korea, volume 30, issue 8, 2011, Pages 436~445
DOI : 10.7776/ASK.2011.30.8.436
In this paper, equivalent properties of 2-2 mode piezocomposites were studied. Variation of the properties of 2-2 mode piezocomposites was analyzed by the finite element method, and the result was compared with experimental measurement data to confirm the validity of the analysis. The equivalent properties of a single phase material to represent the piezocomposite composed of PZT-5H and polymer were derived by the asymptotic averaging method. Accuracy of the derived equivalent properties was enhanced by minimizing the discrepancy between the impedance spectra of full 2-2 piezocomposite and equivalent single phase material resonators of various vibration modes by the least square method. The equivalent properties of 2-2 piezocomposites derived in this study can be utilized to the design of diverse acoustic sensors.
Feature Vector Extraction and Classification Performance Comparison According to Various Settings of Classifiers for Fault Detection and Classification of Induction Motor
Kang, Myeong-Su ; Nguyen, Thu-Ngoc ; Kim, Yong-Min ; Kim, Cheol-Hong ; Kim, Jong-Myon ;
The Journal of the Acoustical Society of Korea, volume 30, issue 8, 2011, Pages 446~460
DOI : 10.7776/ASK.2011.30.8.446
The use of induction motors has been recently increasing with automation in aeronautical and automotive industries, and it playes a significant role. This has motivated that many researchers have studied on developing fault detection and classification systems of an induction motor in order to minimize economical damage caused by its fault. With this reason, this paper proposed feature vector extraction methods based on STE (short-time energy)+SVD (singular value decomposition) and DCT (discrete cosine transform)+SVD techniques to early detect and diagnose faults of induction motors, and classified faults of an induction motor into different types of them by using extracted features as inputs of BPNN (back propagation neural network) and multi-layer SVM (support vector machine). When BPNN and multi-lay SVM are used as classifiers for fault classification, there are many settings that affect classification performance: the number of input layers, the number of hidden layers and learning algorithms for BPNN, and standard deviation values of Gaussian radial basis function for multi-layer SVM. Therefore, this paper quantitatively simulated to find appropriate settings for those classifiers yielding higher classification performance than others.
Efficient Implementation of SVM-Based Speech/Music Classification on Embedded Systems
Lim, Chung-Soo ; Chang, Joon-Hyuk ;
The Journal of the Acoustical Society of Korea, volume 30, issue 8, 2011, Pages 461~467
DOI : 10.7776/ASK.2011.30.8.461
Accurate classification of input signals is the key prerequisite for variable bit-rate coding, which has been introduced in order to effectively utilize limited communication bandwidth. Especially, recent surge of multimedia services elevate the importance of speech/music classification. Among many speech/music classifier, the ones based on support vector machine (SVM) have a strong selling point, high classification accuracy, but their computational complexity and memory requirement hinder their way into actual implementations. Therefore, techniques that reduce the computational complexity and the memory requirement is inevitable, particularly for embedded systems. We first analyze implementation of an SVM-based classifier on embedded systems in terms of execution time and energy consumption, and then propose two techniques that alleviate the implementation requirements: One is a technique that removes support vectors that have insignificant contribution to the final classification, and the other is to skip processing some of input signals by virtue of strong correlations in speech/music frames. These are post-processing techniques that can work with any other optimization techniques applied during the training phase of SVM. With experiments, we validate the proposed algorithms from the perspectives of classification accuracy, execution time, and energy consumption.
A Study on the Improving Speech Intelligibility of Sound Reinforcement System in Reverberant Rooms
Kang, Seong-Hoon ;
The Journal of the Acoustical Society of Korea, volume 30, issue 8, 2011, Pages 468~473
DOI : 10.7776/ASK.2011.30.8.468
Speech may not be clearly understandable in the room that is highly reverberant, due to the loss of consonants intelligibility. Therefore, it is very important to obtain a high sound pressure level of direct sound in reverberant room. A properly designed sound reinforcement system can not provide the good speech intelligibility without the absorption treatments of walls. With using the highly directional speaker, we can transmit the sound energy into only the areas where people are sitting. This can be help to improve the speech intelligibility. In this paper, even in reverberant rooms, it will be shown that the good speech intelligibility can be obtained by only the directivity control of speaker without the room treatment. Also, it would be more improved by the properly room tuning using an equalizer.
Adaptive Beamforming Applied to Bearing Estimation of DIFAR Signal with Highly Directional Noise
Shin, Kee-Cheol ; Kim, Jea-Soo ;
The Journal of the Acoustical Society of Korea, volume 30, issue 8, 2011, Pages 474~481
DOI : 10.7776/ASK.2011.30.8.474
Conventional beamforming is ineffective in producing directional information in system with sparse degree of the freedom such as DIFAR (DIrectional Frequency Analysis and Recording) sonobuoy and in the presence of high directional noise. In this paper, Adaptive beamforming techniques are applied to produce directional spectra from a small number of sensors in highly directional noise environment. Conventional method as well as minimum variance and eigenvectors as adaptive method are evaluated via numerical test and real data.