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 6, Issue 4 - Dec 1987
Volume 6, Issue 3 - Sep 1987
Volume 6, Issue 2 - Jun 1987
Volume 6, Issue 1 - Mar 1987
Selecting the target year
A study on the measurement of SAW velocity on piezoelectric ceramics
Wi, Gyu-Jin ; Gang, Jin-Gyu ; Gang, Won-Gu ; Park, Chang-Yeop ;
The Journal of the Acoustical Society of Korea, volume 6, issue 4, 1987, Pages 5~11
In this paper, the measurement of SAW velocity on piezoelectric ceramic is studied. It can be done by using oscilloscope and pulse generator, and measure the velocity especially when feed-through is appeared. The propagating distance was exactly calculated considering that IDT responses are obtained by convolution theory, therefore the velocity was measured by the above simple method. As the results, the measurement velocity at room temperature was 3480 m/sec for
single crystal and 2770 m/sec for a family of
ceramics with feed-through signal.
Personal Response for Sound according to its Frequency
Kim, Yeong-Il ; Cha, Il-Hwan ;
The Journal of the Acoustical Society of Korea, volume 6, issue 4, 1987, Pages 12~20
Since People have serveral feelings for the sound according to its frequency the responses of sound frequencies for the people have been studies in this paper. The feelings of sound are investigated by questionaire thar are pure tones, waring sounds of automobile and sounds that white noise is passed by one and one-third octave bandpass filter. Experimental results have been shown that people have good response for the pure tone between 160(Hz) and 500(Hz), and have unpleasant response for the pure tone above 1000 (Hz), warning sounds of automobile, and for white noise. Warning sound of automobile horn has been mainly distributed between 1000(Hz) and 2600(Hz). Hence the resells are shown that the responses for warning sound of autombile horn are similar to that for pure tone between 100(Hz) and 2600(Hz). As a results, it is necessary to make warning sound of automobile horn have frequencies between 200(Hz) and 500(Hz) with low level in the residental districts and crowded streets.
Isolated-Word Speech Recognition using Variable-Frame Length Normalization
Sin, Chan-Hu ; Lee, Hui-Jeong ; Park, Byeong-Cheol ;
The Journal of the Acoustical Society of Korea, volume 6, issue 4, 1987, Pages 21~30
Length normalization by variable frame size is proposed as a novel approach to length normalization to solve the problem that the length variation of spoken word results in a lowing of recognition accuracy. This method has the advantage of curtailment of recognition time in the recognition stage because it can reduce the number of frames constructing a word compared with length normalization by a fixed frame size. In this paper, variable frame length normalization is applied to multisection vector quantization and the efficiency of this method is estimated in the view of recognition time and accuracy through practical recognition experiments.
Speaker-Independent Isolated Word Recognition Using A Modified ISODATA Method
Hwang, U-Geun ; An, Tae-Ok ; Lee, Hyeong-Jun ;
The Journal of the Acoustical Society of Korea, volume 6, issue 4, 1987, Pages 31~43
As a study on Speaker-Independent Isolated Word Recognition, a Modified ISODATA clustering method is proposed. This method simplifies the outlier processing and the splitting procedure in conventional ISODATA algorithm, and eliminates the lumping procedure. Through this method, we could find cluster centers precisely and automatically. When this method applied to 11 digits by 10 males and 4 females, its recognition rates of
for K=4 were better than those of the latest Modified K-means,
. Judging from these results, we proved this method the best method in finding cluster centers precisely.
A Study on Korean isolated word recognition using LPC cepstrum and clustering
Kim, Jin-Yeong ;
The Journal of the Acoustical Society of Korea, volume 6, issue 4, 1987, Pages 44~54
In this paper, the problem of LP-model and it's solution by liftering in cepstrum domain are investigated in speaker independent isolated-word recognition. And, clustering technique is discussed for obtaining the reference template. KMA (K-means iteration with average) method, which is transformed from UWA method and K-iteration method, has been suggested and compared with each other for clustering, the result of recognition experiments shows max.
recognition rate when rasied-sign lifter and KMA clustering method is applied.
Fabrication and Properties of
Mun, Dong-Jin ; Do, Si-Hong ; Jang, Ji-Won ;
The Journal of the Acoustical Society of Korea, volume 6, issue 4, 1987, Pages 55~63
piezoelectric ceramics added with 0.2, 0.25, 0.3 mol of
and 0.04 mol of
and 0.05 mol of
and NiO have been fabricated. These ceramics can be poled sufficiently within 10 minutes at
under about d.c. field of 40 kv/cm. Detailed measurement was performed on dielectric constants, cutie temperatures, elastic and piezoelectric properties and coupling factors for the fabricated ceramics. The most value of the piezoelectric coupling factors was coupling factor of thickness mode kt and its value for 0.25 mol of Ca was about
. Dielectric constants of
for 0.25 mol of Ca were 242 and 260, and coupling factor ratio (kt/Kp) and Qm were 6 and 357 respectively,
Underwater Sound Propagation in a range-dependent Shallow water environment
Na, Jeong-Yeol ;
The Journal of the Acoustical Society of Korea, volume 6, issue 4, 1987, Pages 64~73
Low frequency sound propagation in a range-dependent shallow water environment of the Korea Strait has been studied by using the adiabatic coupled mode, ADIAB. The range-dependent environment is unique in terms of horizontal variations of sound velocity profiles, sediment thickness and attenuation coefficients and water depths. For shallow source and receiver depths, the most important mechanism involved in the propagation loss is the depth changing character of mode functions that strongly depends on the local sound velocity profile. Application of the adiabatic coupled mode theory to shallow water environment is reasonable when higher modes are attenuated due to bottom interaction effects. Underwater sound propagation in a range-dependent shallow-water environment.