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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 6, Issue 4 - Dec 1987
Volume 6, Issue 3 - Sep 1987
Volume 6, Issue 2 - Jun 1987
Volume 6, Issue 1 - Mar 1987
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A Study on the Sound Radiation from a Clamped Circular Plate with Viscoelastic layer by Impact Force
Jeon, Jae-Jin ; Lee, Byeong-Ho ;
The Journal of the Acoustical Society of Korea, volume 6, issue 3, 1987, Pages 5~16
In this paper, the sound radiation from a clamped circular plate with a viscoelastic layer excited by impact force is studied both analytically and experimentally. The composite plate vibrations are obtained by using the normal mode analysis and the eigenvalues are obtained by a Mindlin plate theory including the rotary inertia and shear deformation, The contact force developed between the ball and the plate with attached layers is obtained by Hertz contact theory. The radiated sound pressure is calculated by the Rayleigh integral. Prediction of the waveforms of sound radiating from the plate with attached layers and a method for reducing noise generation from the plate by impact force are also shown in this paper.
Measurement of Transmission Loss Using Surface Intensity Method in Building Elements
Kim, Heung-Sik ; Son, Jang-Yeol ; O, Jae-Eung ;
The Journal of the Acoustical Society of Korea, volume 6, issue 3, 1987, Pages 17~22
This study is to propose more reliable test method in evaluating the sound insulation performance of building element in fields. This method involves the measurements of the incident acoustic intensity and transmitted surface intensity. The incident intensity is determined from measurements of the space averaged sound pressure level in source room. The transmitted surface intensity is measured directly using one microphone and one accelerometer. The results of experiments indicate that this new method makes it possible to give more reliable data than the conventional field test method. The values of trans-mission loss measured by this new method are compared favorably with those obtained using the sound intensity method and theoretical calculation(mass law).
A Study on NDE technique using Acoustic Reflection Microscope
Moon, Geon ; Ko, Dae-Sik ; Kim, Jang-Gwon ; Jun, Gye-Seok ;
The Journal of the Acoustical Society of Korea, volume 6, issue 3, 1987, Pages 23~30
In this paper, the characteristic response of reflected signals of acoustic reflection microscope, V(z) phenomenon, has been studied and a new type of NDE technique has been presented. 10 Won coin, aluminium, IC component, and kevlar-epoxy samples have been used for the experiment of NDE and the acoustic microscope operating at a center frequency of 3 MHz has been used in the focused or defocused mode of operation. In experiment, it has been shown that the acoustic microscope has the resolution of
and the defects present on the surface and near surface of samples have been detected by acoustic transducer and imaged on a monitor, and the variation of the contrast of image for samples has been in good agreement with V(z) phenomenon.
A study on the debelopment of the Ultrasonic imaging system for tissue characterization
Choe, Jong-Ho ; Choe, Jong-Su ;
The Journal of the Acoustical Society of Korea, volume 6, issue 3, 1987, Pages 31~42
An ultrasonic pulse-echo diagnostic system for tissue characterization with the estimation of attenuation coefficients is developed and its performance has been examined by system implementation. The system divided into the ultrasonic generator, A/D converter, data communication, computer for signal processing. The methods for estimating the spatial distribution of acoustic attenuation coefficients using the moment analysis are proposed. The experimental results indicate the potential of the methods for tissue characterization.
SAW Serial Type AWQPSK Modulator
Ha, Jun-Ho ; Kim, Geun-Muk ; Park, Yong-Seo ; Hwang, Geum-Chan ;
The Journal of the Acoustical Society of Korea, volume 6, issue 3, 1987, Pages 43~51
In this work an implementation of SAW based serial type AWQPSK modulator is studied. The SAW AWQPSK modulator consisting of input apodized IDT and output uniform IDT with center frequency of 20 MHz and bit rate of 4MHz has been designed and fabricated on
substrate. Measured center frequency and null-to-null bandwidth are 20MHz, respectively. The sidelobe suppression is achieved 60dB below the peak mainlobe level. Measured responses meet the theoretical values with tolerable amount of deviation. SAW-based modulator simplifies the implementation of AWQPSK which uses complex pulse shape as a baseband pulse.
Realization of IIR LDM Digital Filters
Kye, Yeong-Cheol ; Eun, Jong-Gwan ;
The Journal of the Acoustical Society of Korea, volume 6, issue 3, 1987, Pages 52~59
In this paper, we present a method of realizing an infinite impulse response (IIR) digital filter (DF)using linear delta modulation (LDM) as a simple analog/digital (A/D) converter. This method makes the realization of IIR digital filters much simpler than that of conventional ones because it does not require hardware multipliers and a pulse code modulation (PCM) A/D converter. Compared to the finite impulse respponse (FIR) LDMDF of Lee and Un  , this IIR LDMDF requires significantly less computation time.
A Study on Korean Phoneme Classification using Recursive Least-Square Algorithm
Kim, Hoe-Rin ; Lee, Hwang-Su ; Un, Jong-Gwan ;
The Journal of the Acoustical Society of Korea, volume 6, issue 3, 1987, Pages 60~67
In this paper, a phoneme classification method for Korean speech recognition has been proposed and its performance has been studied. The phoneme classification has been done based on the phonemic features extracted by the prewindowed recursive least-square (PRLS) algorithm that is a kind of adaptive filter algorithms. Applying the PRLS algorithm to input speech signal, precise detection of phoneme boundaries has been made, Reference patterns of Korean phonemes have been generated by the ordinery vector quantization (VQ) of feature vectors obtained manualy from prototype regions of each phoneme. In order to obtain the performance of the proposed phoneme classification method, the method has been tested using spoken names of seven Korean cities which have eleven different consonants and eight different vowels. In the speaker-dependent phoneme classification, the accuracy is about
considering simple phonemic rules of Korean language, while the accuracy of the speaker-independent case is far less than that of the speaker-dependent case.