• Proceedings of the IEEK Conference
• /
• 2005.11a
• /
• pp.435-438
• /
• 2005

In this paper, we implemented a system that is called sound engine in musical synthesizer and synthesized a sound of Gayageum using TMS320C6713 DSK. Sound engine consists of two parts: synthesis algorithm and processor. We improved physical modeling using digital waveguide as a synthesis algorithm and we used TMS320C6713 as a processor. The excitation signals that make timbre are stored in memory. When we input parameters, sound engine synthesizes sound of Gayageum. The experimental result shows that synthesized sounds are very similar to real sounds.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.6 no.3
• /
• pp.177-186
• /
• 1998

For the purpose of finding out the sound field characteristics in a cavity of a rectangular enclosure with foamed aluminum lining, analytical and experimental studies are performed with random noise input. Experimental method using two-microphone impedance tube measures the absorption coefficients and the impedances of simple sound absorbing materials. Measured acoustical parameters of the test samples are applied to the theoretical analysis to predict sound pressure field in the cavity. The sound absorp- tion effects from measurements are compared to prediction in both cases with and without foamed aluminum lining in the cavity of the rectangular enclosure.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.15 no.8 s.101
• /
• pp.891-896
• /
• 2005

On the basis of theoretical studies on the effect of the cylinders attached to semi-infinite screens, the tangential sound power-transport parallel to the surface of the attached cylinder is minimized by means of a secondary sound field, which is generated from a part of the attached cylinder. The numerical study shows the possibility of deflecting the incident sound by minimizing the sound field of the upper sections. The acoustical shadow region was more pronounced in both near- and far-field compared to the passive case with rigid surface, i.e. without active control. For a relatively wide frequency range it was possible to enhance shielding effects only with few secondary sources and error microphones. In this paper effects of control parameters on the actively controlled sound field near the top edge of noise barriers are studied. Results of numerical study and model measurements are shown and discussed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.05a
• /
• pp.1228-1233
• /
• 2002

This study is aimed to evaluate a tunneling effect in association with the measurement of sound transmission loss. Based on the formulation for sound transmission loss of a finite panel in the presence of tunnel, variations of the sound transmission loss with parameters such as the location of panel and tunnel depth are investigated. It can be seen that differences in the sound transmission loss are quite evident below coincidence frequency and the sound transmission loss greatly depends on panel location in the tunnel. In comparison with the case without a tunnel, maximum difference occurs in the case where the panel is placed on the center of the tunnel and the flushing with the end of the tunnel gives the better estimation of transmission loss.

• Proceedings of the KSR Conference
• /
• 2005.05a
• /
• pp.332-337
• /
• 2005

In this study the sound field on the surface of the top edge of noise barriers is actively minimized to enhance the shielding effect without increasing the hight of the barrier. First the results of a numerical study are shown; the sound field reduction in the far field due to a cylindrical active headpiece attached to a semi-infinite screen and the related control parameters are investigated. The results of a model experiment in an anechoic chamber and optimal control parameters for noise control on the railway side are shown and discussed.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2007.04a
• /
• pp.309-314
• /
• 2007

Optimal layer sequencing of a multi-layered acoustical foam is solved to maximize its sound transmission loss. A foam consisting of air and poroelastic layers can be optimized when a limited amount of a poroelastic material is allowed. By formulating the sound transmission loss maximization problem as a one dimensional topology optimization problem, optimal layer sequencing and thickness were systematically found for several frequencies. For optimization, the transmission losses of air and poroelastic layers were calculated by the transfer matrix derived from Biot's theory. By interpolating five intrinsic parameters among several poroelastic material parameters, dear air-poroelastic layer distributions were obtained; no filtering or post-processing was necessary. The optimized foam layouts by the proposed method were shown to differ depending on the frequency of interest.

• Journal of the Korean Solar Energy Society
• /
• v.34 no.1
• /
• pp.28-38
• /
• 2014

The effects of geometric parameters (stack position, stack length, resonator tube length) and varying input power over acoustic energy output were investigated. The acoustic laser kit (Garret 2000) was used for the construction of TA lasers. A series of sound pressure level measurements in different orientations did not differ significantly confirming that the sound wave generated could be assumed as a spherical wave. An increase in acoustic pressure was recorded with respective increase in input power, stack and resonator tube lengths owing to their relative influence over heat transfer rate and critical temperature gradient across the stack.

• Proceedings of the IEEK Conference
• /
• 2006.06a
• /
• pp.351-352
• /
• 2006

The objective criterion is necessary to decide the signal for vehicle audio. In this time, the signals have decided by golden ear or some simple parameters. In this paper, we propose the system for sound quality assessment in the vehicle audio signals. The vehicle audio signals were recorded in many vehicles by same condition. From these signals, objective and subjective parameters were extracted and using these signals listening test was done. The function was estimated between three results by simple neural network system. The score of arbitrary signal can be estimated using the function made by three results. In this way, Sound signal quality is assessed objectively.

• Proceedings of the KIEE Conference
• /
• 1998.07g
• /
• pp.2486-2488
• /
• 1998

In this paper, Prameters esimated t using AR model in order to approach linearly the heart sound which include the nonlinear characteristic from the characteristics based on a statistical theory. The parameters which is figured out using AR model is a very important information which show the characteristic heart sound In this paper parameters estimated using autocorrelation method and order selected by proposed Akaike[6] method. Compared the similirities of the spectrums between estimated by using AR model and estimated by using FFT method.

• Science of Emotion and Sensibility
• /
• v.4 no.2
• /
• pp.79-88
• /
• 2001

The objectives of this study were to investigate the relationship of sound parameters with subjective sensation and physiological responses, and to figure out the interrelationship between the subjective sensation and physiological responses. Sound parameters calculated were LPT, ΔL, Δf, loudness[Z], and sharpness[Z]. Subjective sensation was evaluated in 7 aspects(soft-hard, loud-quiet, pleasant-unpleasant, sharp-dull, clear-obscure, rough-smooth, high-low) by thirty participants. We acquired physiological responses when each fabric sound was presented to 10 participants. Physiological signals obtained in this study were electroencephalogram(EEG), pulse volume(PV), skin conductance level(SCL), and LF/HF of heart rate variability. The larger the values of loudness[Z] and LPT, the louder and the rougher the subjective sensation of the perceived fabric sound. Also, the larger the values of loudness[Z] and LPT, the harder, the duller, and the less pleasant. As LPT increased, PV decreased. Loudness[Z] increased in proportion to SCL and so did sharpness[Z] to LF/HF. As the sound perceived to be quieter and clearer, the relative power of slow alpha rose. As the sound perceived to be more pleasant and smoother, PV rose.