• Proceedings of the KSPS conference
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• 2007.05a
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• pp.170-172
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• 2007

The purpose of this study was to examine the syllable structures of ten Korean numeric sounds produced by ten subjects of the same age. Each sound was normalized and divided into onset, vowel, and coda sections. Then, acoustical measurements of each syllable were done to compare the ten sounds. Results showed that there was not much deviation from the grand average duration and intensity for the majority of the sounds except the two diphthongal sounds on which their boundary points varied among the speakers. Some syllable boundaries were quite obvious while others were ambiguous. There seemed some tradeoff among the syllable components depending on their acoustic features.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.751-756
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• 2001

An experimental model of the advanced mixing control in the parallel supersonic-subsonic mixing jet (M$_1$=1.78 and M$_2$=0.30) is numerically simulated. An oscillating wall boundary condition is used as the modeling of a wall cavity for mixing enhancement. The obtained pitot pressure distributions along cross sections at the developing region of the turbulent jets are validated from the good agreement with equivalent experimental data. The similarity solution of dimensional analysis also coincides with this numerical result at the self-similar region sufficiently far from the jet exit.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.768-773
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• 2001

The self-noise from blade cascade at off-design points mainly comes from separated boundary layer and vortex sheddings, and is also dependent on blade shape. If the incidence angle to the cascade increases, the stalling in blades may occur and the noise level increases significantly. The hybrid method using acoustic analogy was employed to compute the far-field noise spectra and directivity patterns from the separated vortex shedding at off-design points of the cascade of impeller. This paper is compared with the experimental data of a stationary cascade in the same conditions. The simulated result is in excellent .agreement with the measured data except th slight under-prediction near the maximum radiation angle for a dipole sound.

• MALSORI
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• no.45
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• pp.15-22
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• 2003

This study is a kind of a preliminary study to develop naturalness of dialog TTS system. In this study, as major characteristics of politeness in Korean, temporal(total duration of utterances, speech rate and duration of utterance final syllables) and F0(mean F0, boundary tone pattern, F0 range) features were discussed through acoustic analysis of recorded data of semantically neutral sentences, which were spoken by ten professional voice actors under two conditions of utterance type - namely, normal and polite type. The results show that temporal characteristics were significantly different according to the utterance type but F0 characteristics were not.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.729-733
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• 2012

Frame structures of High speed train are constructed from corrugated panel and aluminum extruded panel, which have high bending stiffness. Transmission loss of those panels, however, is less satisfactory than other panels with same mass per unit area. Therefore, this study predicted transmission loss of aluminum extruded panels using Finite element method. Specifically, we modeled acoustic cavity above a radiation surface and analyzed correlation between T-slot and transmission loss. Moreover, we examined the effect of boundary condition changes of the structure on transmission.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.5
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• pp.437-443
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• 2012

In this paper, the hybrid method to identify the exciting forces and radiated noise generated from the reciprocating compressor was presented. In order to identify the exciting force, both the acceleration data measured at the compressor shell and numerical finite element model for the full set of compressor were used simultaneously. Applying the identified exciting forces to the numerical model, the velocity responses of all nodes at the shell were predicted. Finally the radiated noises from the vibrating shell were predicted by using the direct boundary element acoustic analysis. For precise numerical modeling, the stiffness of rubber mounts and body springs were identified experimentally from the natural frequencies measured by impact testing. The error of over-all sound pressure level between predicted noise and measured noise was about 2.9 dB.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.4
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• pp.374-383
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• 2011

A numerical model based on a mode method coupling beams and a rectangular plate is proposed to estimate radiation characteristics of an edge-clamped rectangular plate. The radiation efficiency and radiation power in the audio frequency range including the critical frequency can be predicted. The proposed model is rather simple and straightforward and gives reliable results comparing to the previous studies. The estimated radiation characteristics are compared to those of the pinned condition plates and also to those based on the formulae proposed by Maidanik. The radiation efficiency of the clamped plate seems a little higher than that of the pinned plate in the frequency range of corner and edge modes. It is explicitly shown that the power as well as efficiency at high frequencies is not influenced by these edge boundary conditions.

• Journal of the Korean Society of Visualization
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• v.2 no.2
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• pp.3-7
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• 2004

In this paper, computational aeroacoustics (CAA) method is used for flow-noise analysis and flow-noise visualization. High order high resolution scheme of optimized high order compact is used to resolve the small acoustic quantities and large flow quantities at the same time. An adaptive nonlinear artificial dissipation model and generalized characteristic boundary condition are also used. Aeolion tone noise, cavity noise, and jet noise are investigated. The visualizations of flow-noise are successful and characteristics of noise are studied. It is observed that the propagation directivity of noise is different with that of flow. With the help of CAA method, the visualization of noise is possible.

• Speech Sciences
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• v.11 no.2
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• pp.137-150
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• 2004

This paper investigates the prosodic characteristics of discourse boundaries in spontaneous conversation. In this study, the term 'conversation' is taken to refer to a kind of talk in which two or more participants alternate in speaking about particular topics. Such a definition implies that there are at least two sorts of structures in the conversation: textual structure and interactive structure. This requires us to consider not just the textual influences on prosody but also the impact of interactive context. The aim of this study is to find out the acoustic-prosodic means used by speakers to signal discourse boundaries in conversational interaction. The results show that the conflict between the structural level and the interactive level obliges the speakers to reorganize the prosodic variables according to the type of discourse boundaries.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.311-315
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• 2002

The coupled finite/boundary element method is used in numerical analysis for acoustic radiation from the vibration of rectangular composite plate which is simply supported. This analysis is validated using the Wallace equation for an isotropic plate. Active control of sound fields has been carried out using 3 pairs of piezoelectric sensor/actuator and a pair of viscoelastic material by passive constrained layer damping treatment. The results show that the optimal placement of piezoelectric sensor/actuator and VE patch is required to control the sound fields from a vibrating composite plate.