• International Journal of Air-Conditioning and Refrigeration
• /
• v.12 no.2
• /
• pp.87-96
• /
• 2004

Acoustic performances of the steel-wire fabrics manufactured from the crushed tires were experimentally investigated for various thicknesses and bulk densities. The well- known two-cavity method was used to measure the characteristic impedances, the propagation constants, and the absorption coefficients. The normal absorption coefficients measured by the two-cavity method agreed well with those measured by the two-microphone impedance tube method. The experimental results showed that the magnitude and frequency range of the absorption coefficient were controllable by changing the thickness and the bulk density of the steel-wire fabrics. Therefore, the steel-wire fabrics from the crushed tires can be successfully used as a good sound absorbing material.

• The Journal of the Acoustical Society of Korea
• /
• v.8 no.5
• /
• pp.7-22
• /
• 1989

This paper presents basic data on loudness level and loudness along with data obtained by the authors, and describes an application of the idea of masked loudness to perception of music in the presence of noise. It is shown that timbre or sound quality of music is well explained by masked loudness vs frequency characteristic.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 1992.10a
• /
• pp.7-25
• /
• 1992

A definition of timbre was proposed which suggested its application to two attributes of sound: "a characteristic which gives a clue to the identify of the sound source, and the quality of sounds which corresponds to the emotive impression timbre are multidimensional. Using semantic differential, the factorial invariance of timbre was investigated and it was found that three factors were dominant: "pleasant", "powerful" and "metallic". The generality of these three factors has been confirmed in Japan. The relation between timbre and physical values was examined. Finally, the usefulness of verbal expression concerning timbre has also been discussed.ing timbre has also been discussed.

• Proceedings of the Korean Institute of Communication Sciences Conference
• /
• 1984.10a
• /
• pp.1-4
• /
• 1984

This paper is discussed to prepard reference data as a bassic study for Hangeul Character recognition and to extract 2 - Dtransform Korean Charater Image, The 1959 Hangeul Characters is established to form the total 170patterns of 17 formats classified by the initial soun, middle sound and terminal sound and prossessed the 2-D Korean Character Image. Using Superpostion theormm, we are applied to recognition Algorithm. For 50's Hangeul, the recognition efficiency is calculated by computer simulation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2001.11b
• /
• pp.882-887
• /
• 2001

This paper deals with the effect of mass-spring-mass resonance that is a characteristics of the multi-layered panels in order to enhance sound insulation performance. From theoretical and experimental investigation, it is evident that tuning mass-spring-mass resonance by controlling elastic modulus of the core materials is very important to improve the STC value without increasing the weight of panels, resulting in enhancing STC value more than 10 dB.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2006.05a
• /
• pp.1443-1448
• /
• 2006

The reduction of the vehicle interior noise has been the main interest of NVH engineers. The driver's perception on the vehicle noise is affected largely by psychoacoustic characteristic of the noise as well as the SPL. In particular, the HVAC sound among the vehicle interior noise has been reflected sensitively in the side of psychology. Even though the HVAC noise is not louder than overall noise level, it clearly affects subjective perception in the way of making a diver become nervous or annoyed. Therefore, these days a vehicle engineer takes aim at developing sound quality as well as reduction of noise. In this paper, we acquired noises in the HVAC from many vehicles. Through the objective and subjective sound quality evaluation with acquiring noises caused by the vehicle HVAC system, the simple and multiple regression models were obtained for the subjective evaluation 'Pleasant' using the sound quality metrics. The regression procedure also allows you to produce diagnostic statistics to evaluate the regression estimates including appropriation and accuracy. Furthermore, the neural network model were obtained using three inputs(loudness, sharpness and roughness) of the sound quality metrics and one output(subjective 'Pleasant'). And then the models were compared with correlations between sound quality index outputs and hearing test results for 'Pleasant'. As a result of application of the sound quality index, the neural network was verified with the largest correlation of the sound quality index.

• Proceedings of the Korea Contents Association Conference
• /
• 2009.05a
• /
• pp.927-932
• /
• 2009

There is such a kind of characteristic by using the computer digitization technology's interaction. It not only provides the authoring tool, and also has the user-friendly window. The paper based on this kind of interaction, through the sound and the color exchange of information, as well as each information's digitization, carries on about the scientific dielectric related advance research. This research carries on the analysis to the people to the color and the sound perceptual characteristic first, then makes comparison to the people regarding the color and the music perceptual cognition.. The research is about the research stage of the interactive sound installation creation, which shape is carried on the analysis through the extraction image in color. It is based on the perceptual characteristic,is that the algorithm manufacture reasearch of how to make color sonification. Through capturing the non-stop changing colors by camera,it transforms colors into music. The paper's foundation is the fundamental algorithm manufacture of experimental music composition.

• The Journal of the Acoustical Society of Korea
• /
• v.26 no.4
• /
• pp.144-152
• /
• 2007

Conventional research works on the classification of the heart sound signal have been done mainly with the artificial neural networks. But the analysis results on the statistical characteristic of the heart sound signal have shown that the HMM is suitable for modeling the heart sound signal. In this paper, we model the various heart sound signals representing different heart diseases with the HMM and find that the classification rate is much affected by the clustering of the heart sound signal. Also, the heart sound signal acquired in real environments is a continuous signal without any specified starting and ending points of time. Hence, for the classification based on the HMM, the continuous cyclic heart sound signal needs to be manually segmented to obtain isolated cycles of the signal. As the manual segmentation will incur the errors in the segmentation and will not be adequate for real time processing, we propose a variant of the ergodic HMM which does not need segmentation procedures. Simulation results show that the proposed method successfully classifies continuous heart sounds with high accuracy.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2005.05a
• /
• pp.629-633
• /
• 2005

The reduction of the Vehicle interior noise has been the main interest of NVH engineers. The driver's perception on the vehicle noise is affected largely by psychoacoustic characteristic of the noise as well as the SPL. In particular, the HVAC sound among the vehicle interior noise has been reflected sensitively in the side of psychology. In previous study, we have developed to verify identification of source for the vehicle HVAC system through multiple-dimensional spectral analysis. Also we carried out objective assessments on the vehicle HVAC noises and subjective assessments have been already performed with 30 subjects. In this study, the linear regression models were obtained for the subjective evaluation and the sound quality metrics. The regression procedure also allows you to produce diagnostic statistics to evaluate the regression estimates including appropriation and accuracy. Appropriation of regression model is necessary to $R^2$ value and F-value. And testing for regression model is necessary to Independence, Homoscedesticity and Normality. Also we selected optimum layout of damping material using Taguchi method. As a result of application, sound quality is improved by more quiet, powerful, expensive, smooth.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2004.05a
• /
• pp.568-571
• /
• 2004

This research estimated the physical. mechanical characteristic and the character of sound absorption according to target void ratio of porous concrete and the mixing ratio of recycled aggregate for the valid utilization of recycled aggregate using waste concrete and sound reduction out of a road, a railway, a residential street, and a downtown area. As a result of the test, compressive strength tended to be a radical strength fall when target void ratio was $25\%$ and contents of recycled aggregate exceeded over $50\%$. Also, the character of sound absorption of porous concrete which used recycled aggregate using waste concrete was the most excellent when target void ratio was $25\%$, and the influence by contents of recycled aggregate was trivial. Therefore, when the strength and the character of sound absorption of porous concrete are considered, it is proved valid that proper target void ratio was $25\%$ and contents of recycled aggregate using waste concrete was $50\%$ or so.