• Proceedings of the KOSOMBE Conference
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• v.1997 no.11
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• pp.75-78
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• 1997

In this paper we present new sound spectral analysis methods or prosthetic heart valve sounds. Phonocardiograms(PCG) of prosthetic heart valve were analyzed in order to derive frequency domain feature suitable or the classification of the valve state. The fast orthogonal search method and MUSIC (MUltiple SIgnal Classification) method are described or finding the significant frequencies in PCG. The fast orthogonal search method is effective with short data records and cope with noisy, missing and unequally-spaced data. MUSIC method's key to the performance is the division of the information in the autocorrelation matrix or the data matrix into two vector subspaces, one a signal subspace and the other a noise subspace.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.572-574
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• 2014

Researches on three-dimensional multimedia has been performed actively in recent years. Virtual sound technology corresponding to virtual image should be provided to implement 3D multimedia with high quality. Head-related transfer function (HRTF) plays a key role in this research area. HRTFs measured in changing azimuth, elevation, and distance for each and every subject is necessary for ideal solution. However, it is practically impossible to measure all subjects' HRTFs, so various HRTF databases have been built by many researchers. Because HRTF displays quite different aspects from subject to subject, HRTF of dummy head has been used for generic usage. However, mannequin's HRTF showed much worse performance comparing with individual case so this solution should be improved. From previous work, standardization of HRTF based on tensor-singular value decomposition method has been proposed. For effective extraction of standard HRTF, three different decomposition methods are compared in this paper.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.1
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• pp.16-24
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• 2011

The sound speed of seawater can be calculated by the empirical formula as a function of temperature, salinity and pressure. It is little affected by salinity because the average salinity is 34 psu and varies within a few psu seasonally and spatially in the ocean. Recently, low-salinity water of 24 psu flows into the western sea area of Jeju Island due to the flood of the Yangtze River in China during summer, affecting sound speed profile. In this paper, it was analyzed how environmental changes affected to the underwater communication - the sound speed of low-salinity water was calculated, and the communication channel was estimated by the simulated acoustic rays while the transmitting and receiving depth and the range were varied with and without the low-salinity layer. And The BER (Bit error rate) was calculated by BPSK(Binary phase shift key) modulation and the effects of the low-salinity water on the BER was investigated. The sound speed profile was changed to have positive slope by the low-salinity layer at the sub-surface up to 20 m of depth, forming acoustic wave propagation channel at the sub-surface resulting in the decrease of most of the BER Consequently, this paper suggests that it is important to consider changes of the ocean environment for correctly analyzing the underwater communication and the detection capability.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.4
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• pp.892-898
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• 2008

3D rapid prototyping is the manufacturing technology to fabricate a prototype with the data stored in a computer, which differs from conventional casting technology in terms of an additive process. Various 3D rapid prototyping techniques such as stereolithograpy. fused deposition modeling. selective laser sintering, laminated object manufacturing have been developed but among them, 3D inkjet printing has a unique feature that materials could be jetted to directly form the body of a prototype, which could be a finished product functionally and structurally. However, this needs ink with a high solid content, which tends to increase the dynamic viscosity of ink. The increase of ink viscositytends to restrict the jettable range of ink and hence the jetting conditions should be optimized. The intrinsic speed of sound in a hot melt ink with ceramic nanoparticles dispersed is one of key components to determine the jettable range of ink. In this paper, the way to measure the intrinsic speed of sound in a hot melt ceramic ink is proposed and its influence on the jetting condition is discussed.

• Journal of Korean Association for Spatial Structures
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• v.10 no.3
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• pp.75-80
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• 2010

The present study tried to provide useful data for the acoustic design of sound amplification system with measuring and analyzing subjective preference and intelligibility by varying the number of speakers and their directivity. The results suggest that the room absorption plays a key role in subjective responses of listeners and the large sound absorption of ceiling contributes to the increase of intelligibility. Also, larger number of speakers with narrow directivity improves perceived intelligibility when speakers were installed at the lower height. However, the highest degree of intelligibility and preference were obtained when speakers were installed close enough to the sound absorptive ceiling. The highest intelligibility and preference were observed when 8 to 10 speakers with the directivity of 60 degree were used.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.659-664
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• 1999

The majority of published conclusions about structural configuration effects of bond strength were based on the observed performance of test specimens and their interpretations are mostly empirical and statistical. The empirical and statistical interpretation on bond strength have to be replaced by rational models based on simple, sound and verifiable mechanical principles. It is likely that such models also represent the key to a deeper understanding of some existing experimental data on bond strength. The presented truss model is capable of explaining failure modes involving bond slip that cannot be explained by current truss model.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1996.06b
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• pp.77-81
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• 1996

In order to conform to the needs of effective program production in multimedia era, we are studying Desk Top Program Production system. With the DTPP, users can easily produce multimedia program including video, sound, and ancillary data, and freely handle video images synthesizing video components retrieved from video database. This paper describes the new program production system, DTPP and its key technologies such as cooperative program production via multimedia network, indexing and utilization of attribute information of images, and image segmentation and spatio-temporal editing.

• MALSORI
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• no.43
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• pp.73-88
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• 2002

In this paper, for natural facial synthesis, lip-synch algorithm based on key-frame method using RBF(radial bases function) is presented. For lips synthesizing, we make viseme range parameters from phoneme and its duration information that come out from the text-to-speech(TTS) system. And we extract viseme information from Av DB that coincides in each phoneme. We apply dominance function to reflect coarticulation phenomenon, and apply bilinear interpolation to reduce calculation time. At the next time lip-synch is performed by playing the synthesized images obtained by interpolation between each phonemes and the speech sound of TTS.

• Proceedings of the KSPS conference
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• 2000.07a
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• pp.117-134
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• 2000

Kim, Key-Seop(2000). English Restructuring and A Use of Music in Teaching English Pronunciation. JSEP 2000 voU This study has two-fold aims: one is to clarify the restructuring of English in utterance, and the other is to relate it to teaching English pronunciation for listening and speaking with a use of music and song by suggesting a model of 10-15 minute pronunciation class syllabus for every period in class. Generally, English utterances are restructured by stress-timed rhythm, irrespective of syntactic boundaries. So the rhythmic units are arranged in isochronous groups, of which the making is to attach clitic(s) to a host or head often leftwards and sometimes rightwards, which results in linking, contraction, reduction, sound change and rhythm adjustment in utterance, just as in music and song. With English restructuring focused on, a model of English pronunciation class syllabus is proposed to be put forward in class for every period of a lesson or unit. It tries to relate the focused factor(s) in pronunciation to the integrated, with teaching techniques and music made use of.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.5
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• pp.17-37
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• 2003

This paper presents the ASVO (Automation-considered SVO) Logic that can be used for verifying authentication and key distribution protocols. The ASVO logic was designed for automatic verification, in a way to modify the SVO logic, one of the most famous authentication logics. The ASVO logic is syntactically and semantically sound, and requires relatively simple verification steps. Also we implemented the Isabelle/ASVO system which supports semi-automated verification, by using the Isabelle/Isar system.