• The Journal of the Acoustical Society of Korea
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• v.30 no.2
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• pp.107-113
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• 2011

This paper describes a development of a loop filter design in a physical modeling of the plucked string instrument. The conventional method proposed by V$\"{a}$lim$\"{a}$ki cannot estimate right parameters if a sound has either very short sustain or no sustain. In order to overcome this drawback, we propose the use of the decay region and 5 to 20 harmonics of the sound in the estimation of loop filter parameters. The most appropriate filter coefficient is chosen by frequency signal to noise ratio. To verify the performance of the proposed method, the guitar, gayageum and geomungo were selected as the target because they have different shape, structure, and material of strings. Regardless of the duration of harmonics, the proposed method was able to estimate the loop filter parameters representing frequency-dependent damping of harmonics.

• Science of Emotion and Sensibility
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• v.13 no.1
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• pp.215-224
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• 2010

This paper is designed to investigate the attributes of sound and emotion resided in traditional Eastern thought by looking into acoustic theories such as Sunguarakron (聲有哀樂論) in Akgi(樂記), Sungmuaerakron(聲無哀樂論) of Haegang and Akhakgebum(樂學軌範), Chongiron(天機論) in Choson(朝鮮) dynasty. Six types of emotions, namely sadness, pleasure, happiness, anger, respect, and, affection (哀心, 樂心, 喜心, 怒心, 敬心, 愛心) which is related with sounds was closely reviewed through Akgi(樂記). Also attributes of sounds such as loudness, sharpness, pitch, roughness, fluctuation strength and pleasantness was corresponded with plain & complicated(單複), pitch, good & bad(善惡) slow & fast(舒疾), loud & quiet(猛靜) respectively. In addition to this, this paper is narrowed down that the basic ideas about sound and emotions of Choson(朝鮮) confucian scholar was based on theory of music and rhythm on Akgi(樂記). Furthermore, the relationship between expressed sound and emotions which was revealed in Chongiron(天機論) has been examined. Finally, various applied research and studies will be promoted through this study, because this study will provide foundation which supports sounds and emotions of Eastern.

• Tunnel and Underground Space
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• v.19 no.2
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• pp.146-157
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• 2009

An experimental study of accelerated weathering on mudstone sample specimens from Haman, Gyeongnam was performed to investigate the variations of physico-mechanical properties of deteriorated rocks due to freeze-thaw weathering. Each complete cycle of freeze and thaw lasted 24 hours, comprising 2 hours of saturating in vacuum chamber, 8 hours of freezing at $-16{\pm}1^{\circ}C$ and 14 hours of thawing at room temperature. Total of 55 cycles of freeze-thaw were completed with measuring the index properties as well as geometries of microfractures. The measured specific gravity and P-wave velocity found to decrease with increasing freeze-thaw cycles. On the other hand, absorption ratio and effective porosity were continuously increased with increasing freeze-thaw cycles. It was found that the index properties of deteriorated sample specimen depend on its initial properties and flaws in rock. The size and density of the traces of the microfracture on slab specimen exhibited abrupt changes after 30 cycles of freeze-thaw weathering. The results obtained in this study show that the box fractal dimension($D_B$) given in this paper has the strong capability of quantifying the size and density of the microfracture.