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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 9, Issue 6 - Dec 1990
Volume 9, Issue 4 - Aug 1990
Volume 9, Issue 3 - Jun 1990
Volume 9, Issue 2 - Apr 1990
Selecting the target year
A study on traffic Noise by Platoon Dispersion
Oh, Jae-Eung ; Yim, Tong-Kyu ; Park, Kil-Su ;
The Journal of the Acoustical Society of Korea, volume 9, issue 3, 1990, Pages 5~10
This study was examined for traffic noise by platoon dispersion in relation to traffic flow till platoon reach steady driving condition after starting from stopline. Platoon dispersion factor was calculated and evaluated by the following input data : traffic volume, travel time, pass time.
The Acoustical Characteristics of the Hae-keum
Lim, Moo-Yeol ; Yoon, Wha-Joong ;
The Journal of the Acoustical Society of Korea, volume 9, issue 3, 1990, Pages 11~23
In order to investigate the acoustical characteristics of the Hae-keum (Korean traditional musical instrument) tone quality, the spectrum and wave form of Hae-keum sounds were analyzed by the FFT Analyzer. The analysis was carried out by the varying of the tension of Hae-keum strings, the positions of bridge and the top plate's thickness of Hae-keum respectively. According to the experiment, the following results are obtained ; the over tone's amplitude nearby the top plate resonance frequency is greater than the fundamental tone's amplitude because the top plate resonance frequency is higher than the fundamental tone's frequency. Tone qualities are better when the bridge is situated in the middle of top plate and the tension of strings is larger. The inharmonicity coefficient of the Hae-keum's second string is 0.049 cents/
. The brilliance and richness is poor, because we seldom found the over tone over 5kHz and the inharmonicity of the Hae-keum is greater than that of a violin. Also we confirmed that we are able to get the best tone quality in 4.5mm thickness of the Hae-keum's top plate.
Design and Fabrication of EMAT for Excitation of SAW
Kim, Heung-Ki ; Lee, Jae-Seung ; Jun, Kye-Suk ;
The Journal of the Acoustical Society of Korea, volume 9, issue 3, 1990, Pages 24~30
In this paper, meander line type EMAT(Electro-Magnetic Acoustic Transducer) has been designed and fabricated with effective properties for detecting flaw existing within one wavelength in depth, and its characteristics have been analyzed. For the purpose of getting effective dynamic and static magnetic intensity, the coil has been arrayed using wire with interval of 0.75 mm and width of 0.65 mm and permanent magnets with 1500 Gauss have been constructed respectively. The center frequency and fractional bandwidth of the fabricated EMAT was 2 MHz and 36% respectively and its impulse response has been measured by non-contacting technique(the distance between the conducting media and the coil was 0.15mm). In the measuring results, it has been shown that Insertion Loss(IL) was 45.46dB and it was good agreement with theoretical result.
Ultrasonic Detection of Small Crack in Studs[Bolts] by Signal-Conditioning
Suh, Dong-Man ; Moon, Hong-Chin ; Choi, Kyu-Hoon ; Kim, Chong-Kyo ;
The Journal of the Acoustical Society of Korea, volume 9, issue 3, 1990, Pages 31~41
It is difficult to detect such flaws as stress-corrosion cracking or corrossion wastage(loss of bolt diameter) in the threads. In many cases the critical size of a flaw is very small(1-2mm order). This paper describes how it is possible to discriminate small flaw indications in threads using the time difference of thread signals [TDTS] by a signal-conditioning technique.
Auditory Neural Information Processing Modeling for Speech Recognition
Lee, Hee-Kyu ; Lee, Kwang-Hyung ;
The Journal of the Acoustical Society of Korea, volume 9, issue 3, 1990, Pages 42~47
A neural auditory system is studied for the aim of making better speech recognition systems. The cochlear mechanics is described. A IIR digital filter modeling of basilar membrane is discussed for the speech recognition. A multi-layer model of consonant recognition using phoneme detection filters and discriminant functions for feature estimation is constructed. This model shows more then 90% recognition rate in consonants.
The Effect of Sampling Frequency and Pulse Bandwidth on Estimating Mean Frequencies in an Ultrasonic Doppler System using the Second-Order Sampling
Ahn, Young-Bok ; Park, Song-Bai ;
The Journal of the Acoustical Society of Korea, volume 9, issue 3, 1990, Pages 48~55
We analyze the effect of second-order sampling on estimating the mean frequency of the Doppler signal. In order to reduce the sampling frequency of analogue-to-digital converter, it is possible to obtain the Doppler signal by sampling the radio frequency echo signal with the low frequence of
/9 instead of
is the center frequency of the transmitted signal. The computer simulation and experiments show that if the narrowband signal is transmitted as is usual in the Doppler system, the error of the mean frequency estimates due to the low sampling frequency is negligible.
Energy Spectrum of Underwater Explosive Sound
Kim, Sung-Boo ;
The Journal of the Acoustical Society of Korea, volume 9, issue 3, 1990, Pages 56~61
A New theoretical energy spectrum model for underwater explosive sound is introduced in order to calculate the precise spectral energy levels. This model is obtained by Fourier analysis of Gaussian formula which accurately represents the pressure wave generated from Underwater explosions. In case that explosive energy is very low. The spectrum levels which are obtained from the new theoretical model are in good agreement with the experimental spectrum levels, while the Weston model using impulse formula cannot interpret the experimental results.
Applications of Underwater Acoustics for Development of Ocean Resources
Na, Jung-Yul ;
The Journal of the Acoustical Society of Korea, volume 9, issue 3, 1990, Pages 62~65
Actual Condition and Noise Reduction of Indoor Noise in Apartment Houses
Kim, Heung-Sik ;
The Journal of the Acoustical Society of Korea, volume 9, issue 3, 1990, Pages 66~74
Studies on the Acoustic Properties of the NIRI's Acoustic Rooms
Kim, Kwan-Choong ; Hong, In-Pyo ;
The Journal of the Acoustical Society of Korea, volume 9, issue 3, 1990, Pages 75~82