• 한국음향학회:학술대회논문집
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• 한국음향학회 1994년도 제11회 음성통신 및 신호처리 워크샵 논문집 (SCAS 11권 1호)
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• pp.91-94
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• 1994

This paper is a study on the design and implementation of the Korean Tet-to-Speech system. In this paper, parameter symthesis method is chosen for speech symthesis method and PARCOR coeffient, one of the LPC analysis, is used as acoustic parameter, We use a diphone as synthesis unit, it include a basic naturalness of human speech. Diphone DB is consisted of 1228 PCM files. LPC synthesis method has defect that decline clearness of synthesis speech, during synthesizing unvoiced sound In this paper, we improve clearness of synthesized speech, using residual signal as ecitation signal of unvoiced sound. Besides, to improve a naturalness, we control the prosody of synthesized speech through controlling the energy and pitch pattern. Synthesis system is implemented at PC/486 and use a 70Hz-4.5KHz band pass filter for speech imput/output, amplifier and TMS320c30 DSP board.

• 대한기계학회논문집
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• 제17권8호
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• pp.1971-1979
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• 1993

In this paper, a new method to estimate stress status in metal nondestructively by using nonlinear dependency of sound speed on stress is proposed. For the purpose, equivalent nonlinear elastic constants up to fourth-order are introduced and a new characteristic parameter given as a function of these constants is presented. And a concrete system to measure the characteristic parameter is constructed by electromagnetic pumping wave and ultrasonic probing wave system. Some experimental results for Al alloy showed that the estimation of stress status in metal is possible by the proposed method.

• 음성과학
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• 제10권4호
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• pp.125-136
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• 2003

Speech coding techniques have been studied to reduce the complexity and bit rate but also to improve the sound quality. CELP type vocoder, has used as a one of standard, supports the great sound quality even low bit rate. In this paper, the preprocessing of input speech to reduce the bit rate is the different with the conventional vocoder. The different kinds of parameter are used for the preprocessing so this paper is compared with theses parameters for finding the more appropriate parameter for the vocoder. The parameters are used to synthesize the speech not to encode or decode for coding technique so we proposed the simple algorithm not to have the influence on the processing time or the computation time. The parameters in used the preprocessing step are speaking rate, duration and PSOLA technique.

• The Journal of the Acoustical Society of Korea
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• 제18권2E호
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• pp.18-23
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• 1999

This paper proposes a method of separately determining three intrinsic mechanical parameters of an unknown object in the framework of ultrasound inverse scattering tomography. Those parameters are the speed of sound, density, and absorption whose values are given as the solution of an inhomogeneous Helmholtz wave equation. The separate reconstruction method is mathematically formulated, the integral equations are discretized using the sinc basis functions, and the Newton-Raphson method is adopted as a numerical solver in a measurement configuration where the object is insonified by an incident plane wave over 360˚ and the scattered field is measured by detectors arranged in a rectangular fashion around it. Two distinct frequencies are used to separate each parameter of three Gaussian objects that are either located at the same position or separately from each other. Computer simulation results show that the separate reconstruction method is able to separately reconstruct the three mechanical parameters. The absorption parameter turns out to be a little difficult to reconstruct as compared with the other two parameters.

• International Journal of Automotive Technology
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• 제6권4호
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• pp.367-374
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• 2005

This paper proposes a sound quality index to evaluate the vehicle interior noise. The index was developed using a correlation analysis of an objective measurement and a subjective evaluation data. First, the objective set of measurements was obtained at two specified driving conditions. One is from a wide-open test condition and the other is from a constant-speed test condition. At the same time, subjective evaluation was carried out using a score of ten scale where 17 test engineers participated in the experiment. The correlation analysis between the psycho-acoustic parameters derived from the objective measurement and the subjective evaluation was performed. The most critical factors at both test conditions were determined, and the corresponding equations for the sound quality were obtained from the multiple factor regression method. Finally, a comparative work between previous index and present index was performed to validate the effectiveness of the proposed index.

• 소음진동
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• 제8권6호
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• pp.1043-1052
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• 1998

The noise sources in the outdoor unit of RAC are identified by the sound intensity method. The main noise sources are compressor noise and fluid noise which is caused by the fan. heat exchanger and shroud. First. the fluid noise is reduced through the design of new fan and shroud. reduction of the system resistance by rearrangement of heat exchanger. and optimization of the complex parameter between the fan and shroud. Next, in order to reduce the compressor noise, the new shape of compressor mount and sound-proof material was applied. As a result, the overall noise was reduced by 4∼5dB (A).

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 춘계학술대회 논문집
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• pp.662-663
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• 2014

In most vehicle manufactures have traditionally relied on find-fix method of human auditor, mainly due to variation excitation source. To solve the BSR noise, the requirements for BSR test are presented in terms of detection of noise source, analysis of time-frequency and sound pressure, sound quality for noise. A number of new technology direction, particularly in the field of noise source identification application and psycho-acoustics from the Zwicker's sound quality parameter, the computed objective sound metrics and subjective jury test result.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.778-782
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• 2004

Floating floor structure, which is mainly adopted for reducing interior noise of railway vehicle, is known that it is superior to single wall in respect of sound transmission loss. The dynamic characteristic of the support in the floating floor that is one of the important design variables in floating floor structure can change the sound and vibration insulation properties of it. From excitation test, the dynamic stiffness and loss factor of the support are evaluated. They are used as input parameter for analyzing the sound transmission loss of floating floor. Predicted transmission loss is compared with the prototype-car test results.

• 한국소음진동공학회논문집
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• 제12권1호
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• pp.12-20
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• 2002

To control the noise of an enclosed sound field, we built a state space model using the acoustic modal parameter description. Using the state space model, we can investigate the controllability and observability, and find an appropriate position of control speaker and microphone to control sound field of the enclosed space. We implemented LQR(linear quadratic regulator) controller and reduced order observer to reduce the first acoustic mode. Experiments showed satisfactory results of 4∼10 dB reduction of magnitude of the first acoustic mode, and support the feasibility of the proposed scheme to lightly damped acoustic field.

• 한국주거학회:학술대회논문집
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• 한국주거학회 2003년도 정기총회 및 추계학술대회
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• pp.59-65
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• 2003

The present article has the purpose of evaluating subjective response of Won Buddhism sanctums by psychoacoustics experiment. Furthermore, basing on this experiment, the present article makes a suggestion of a physical sound-evaluating index. To achieve the purpose, I conducted an psychoacoustics experiment at 6 sanctuaries out of the representing 40 sanctuaries of Won Buddhism sanctums, which size is bigger than 1,000 m$^3$. I made a reanalysis with 3 Buddhist sanctums out of the subjects of psychoacoustics experiment which are generally rated superior. From the result, I can make each evaluation type into two types, sound clarity and space sense of sound. Also, I make various suggestions of physical parameter, with which I can evaluate the proper sound condition for Won Buddhism sanctums.