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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
Selecting the target year
Transmission Characteristics of FFH-SS Communication System in Fading Media
Kim, Won-Hu ; Jeon, Gye-Seok ;
The Journal of the Acoustical Society of Korea, volume 6, issue 1, 1987, Pages 5~14
In this paper, the transmission characteristics of a frequency-hopped spread spectrum communication system operating in the presence of both time and frequency-selective fading channel is presented. The receiver is a binary noncoherent matched-filter FFH-SS system with square-law combiner. The probability of error to the variations of the parameters such as signal-to-noise ratio, selectivity of a channel, and power ratio is derived with the use of diversity concept without considering the data rate. The analysis of the data for probability of error shoves that the performance of FFH-SS system in time-selective fading channel is better than in frequency-selective fading channel.
A Method of Secreting Digital Signals by FWHT
Kim, Jang-Bok ;
The Journal of the Acoustical Society of Korea, volume 6, issue 1, 1987, Pages 15~22
Fast Walsh-Hadamard Transform algorithm is discussed for secreting digital signals in ISDN. 16 characters are used for the password to control the coefficients of FWHT. And it gives above
codes. The FWHT module in presented in machine language. So it is applicable to compact cipher system or firmware system. Computer simulation showed secreting characteristics in printed data for N=128.
A Study on Creating Reference Pattern for Recognition of Korean Isolated Word
Kim, Gye-Guk ; Go, Deok-Yeong ; Lee, Jong-Ak ;
The Journal of the Acoustical Society of Korea, volume 6, issue 1, 1987, Pages 23~28
This paper discusses a reference pattern creation for a speaker-independent Korean isolated word by using the clustering. Tn this paper we permitted to top 3 clusters and created reference pattern by Minimax Criterion. The features parameter used the LPC Coefficients and Autocorrelation and simple Itakura distance measure was used to measure similarity between patterns. With word reference patterns obtained as described above the recognition rate was within one choice only
, two choice only
, three choice only
A Study on the Estimation of Temperature Distribution in Ultrasonic Hyperthermia by 1-Dimensional FEM Model
Ha, Jae-Gyu ; Seong, Goeng-Mo ;
The Journal of the Acoustical Society of Korea, volume 6, issue 1, 1987, Pages 29~38
In clinical applications of hyperthermia, temperatures can be measured at only a few locations, whereas accurate temperature profiles need to be known for efficient therapy. For doing this, bio-heat transfer equation was modified into 1 dimensional 2 boundary value problem for simplicity and the efficiency of time, and solved by Galerkin's method. The results were then applied to annular array transducer for both the calculation of its axial temperature distribution and the estimation of temperature profiles from a few measured temperature data.
An Equivalent Circuit of the Piano and a Tonal Improvement Scheme in the Bass Registers
Du, Se-Jin ; Seong, Goeng-Mo ;
The Journal of the Acoustical Society of Korea, volume 6, issue 1, 1987, Pages 39~47
It is well-known that analogizing a dynamic system to an equivalent circuit is a powerful tool on the analysis of the system. In this paper, an equivalent circuit of the piano has been constructed by the structural and acoustical analysis to visualize the sounding mechanism. Utilizing the mechanical reactance curve of the soundboard, a new method of reducing che inharmonicity in low frequency range has been built. With this method, by only choosing the proper excitation point on the soundboard, it will be possible to minimize the inharmonicity and thus to obtain mellow bass tone. It is shown that the missing fundamental in the lowest scale range results predominatly from the fact that the radiation impedance in such low frequencies is nearly pure reactive.
A Study on the Noise Source Identification of Refrigerator Compressor
O, Jae-Eung ; Lee, Chang-Ho ; Lee, Myeong-Ryeol ; Yeom, Seong-Ha ;
The Journal of the Acoustical Society of Korea, volume 6, issue 1, 1987, Pages 48~57
It is well known that the major noise source of Refrigerator is compressor, and due to the tendency of higher quality and more lighting of manufactured goods, the importance of prevention and reduction of a noise is increasing. In this paper, in order to prevent and reduce such a noise, sound pressure level and acoustic intensity are measured for compressor, and the result of these measurements, the noise radiation characteristics of compressor are reconized. And the experimental modal analysis is applied to the compressor to identify the noise sourcce. As the results of this study, we come to know that the spring, which is used to reduce vibration, does not reduce vibration efficiently, and compressor shell and its mounting system effect the noise radiation.
A Study on the Specifications of the Audible Tones of the Switching System for the Telephone Service
Lee, Hui-Jeong ; Won, Dong-Ho ; Kim, Byeong-Chan ;
The Journal of the Acoustical Society of Korea, volume 6, issue 1, 1987, Pages 58~65
The audible tones of switching system employed in the country at present do not only disagree with CCITT Recommendation Q35, but also are different in the specifications and the sense of hearing. Such a discord with the specifications and the sense of hearing causes a subscriber and an operator to confuse. In this paper characteristics of the sense of hearing of them and the accuracy of tone specifications are studied and novel unified audible specifications are proposed. And it is showed that the digital tone generation of digital switching systems can be implemented readily, using a ROM.