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

• The Journal of the Acoustical Society of Korea
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• v.28 no.2
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• pp.119-126
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• 2009

This paper describes the non-stringed guitar composed of laser strings, frets, sound synthesis algorithm and a processor. The laser strings that can depict stroke and playing arpeggios comprise laser modules and photo diodes. Frets are implemented by voltage divider. The guitar body does not need to implement physically because commuted waveguide synthesis is used. The proposed frets enable; players to represent all of chords by the chord glove as well as guitar solo. Sliding, hammering-on and pulling-off sounds are synthesized by using parameters from the voltage divider. Because the pitch shifting corresponds to the time-varying propagation speed in the digital waveguide model, the proposed model can synthesize vibrato as well. After transformation of signals from the laser strings and frets into parameters for synthesis algorithm, the digital signal processor, TMS320F2812, performs the real-time synthesis algorithm and communicates with the DAC. The demonstration movieclip available via the Internet shows one to play a song, 'Arirang', synthesized by proposed algorithm and interfaces in real-time. Consequently, we can conclude that the proposed synthesis algorithm is efficient in guitar solo and there is no problem to play the non-stringed guitar in real-time.

• The Journal of the Acoustical Society of Korea
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• v.25 no.8
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• pp.362-369
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• 2006

In this paper, we improve a Physical modeling of sanio gayageum and synthesize sounds by right-hand playing styles. Parameters of loop filter are estimated from decay region of recorded sound. That results in improved accuracy and reduction of computational costs. Body is implemented to a resonator which has characteristics of main resonances extracted from impulse response. Residual signal with main resonances removed is used as excitation signal of proposed model. Amok alter is approximated to frequency response of amok and is implemented to the 15th order all-role digital filter. Beating (by middle and index finger) among the right-hand playing styles is represented by feedforward comb filter. Parameters of this filter are extracted from recorded sound. The synthesized sounds using improved physical model of sanjo gayageum. plucking and beating, are pretty similar to original sounds.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.8
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• pp.691-701
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• 2017

The barbell squat is a fundamental physical exercise for strengthening the lower body and core muscles. It is an integral part of training and conditioning programs in sports, rehabilitation, and fitness. In this paper, we proposed a virtual test framework for squat exercises using a Smith machine to simulate joint torques and muscle forces, based on an integrated product-human model and motion synthesis algorithms. We built a muscular skeletal human model with boundary conditions modeling the interactions between the human body and a machine or the ground. To validate the model, EMG, external forces, and squat motions were captured through physical experiments by varying the foot position. A regression-based motion synthesis algorithm was developed based on the captured squat motions to generate a new motion for a given foot position. The proposed approach is expected to reduce the need for physical experiments in the development of training programs.

• Journal of the Korea Computer Graphics Society
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• v.15 no.1
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• pp.25-34
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• 2009

Sound is very important element to enhance and reinforce reality and immersion of users in virtual reality and computer animation. Recently, significant researches about sound modeling are presented in computer graphics community. In this article, main subjects are explained and major researches are reviewed based on the sound papers presented in computer graphics community. Specially, several papers about following two subjects are reviewed in this paper: 1) synthesing sound using physically-based laws and generating sound synchronized with graphics. 2) spatializing sound and modeling sonic environment. Many research about sound modeling have been focused on more efficient modeling of real physical law and generate realistic sound with limited resources. Based on this concept, various papers are introduced and the relationship between researches about sound and graphics is discussed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.6
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• pp.1099-1104
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• 2009

Cellular Automata(CA) has been used as modeling and computing paradigm for a long time. While studying the models of systems, it is seen that as the complexity of the physical system increase, the CA based model becomes very complex and becomes to difficult to track analytically. Also such models fail to recognize the presence of inherent hierarchical nature of a physical system. In this paper we analyze the properties of GF($2^p$) multiplue attractor cellular automata(GF($2^p$) MACA) C and give a method of synthesis of C which is a special class of hierarchical cellular automata proposed as an alternative to solve the problem.

• The Journal of the Acoustical Society of Korea
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• v.20 no.1
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• pp.3-12
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• 2001

In physical modeling of plucked string instruments, the vibration of a string is typically simulated by the linear system. Currently the Digital Waveguides of J.O.Smith[1] are widely used to get a high quality sound of the plucked string instrument. He used the wave equation to derive the Digital Waveguides and emphasized the time variable. In this thesis, new model of plucked string is proposed to improve the sound quality emphasizing the spatial variable of the wave equation. In our model, we used the fixed sampling interval which is not dependent on the speed of the wave. So we could get more detailed description of wave movement by the time variable. As a result, the new model could produce a higher quality sound of plucked string instrument.

• The Journal of the Convergence on Culture Technology
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• v.6 no.2
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• pp.455-460
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• 2020

As computer hardware and computer graphics technologies have developed in recent years, one can find research on the creation of bubbles. However, it is not easy to find soap bubbles that are modeled and rendered using actual physical parameters. The bubbles are expressed in a variety of models and colors depending on which tool is used, which strength is used, and the conditions of the surrounding environment. Therefore, in this paper, we present synthetic methods to create virtual soap bubbles based on physical parameters derived from some straws such as the bubbles' diameter over time and the number of bubbles when blowing. On the top of that, we will show a model of a soap bubble that can be usable in a virtual reality contents and optimized with rendering parameters.

• Nuclear Engineering and Technology
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• v.51 no.5
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• pp.1272-1278
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• 2019

A lumped kinetic modeling platform is developed to investigate the coupled nuclear/thermo-fluid features of the closed natural circulation loop in a low power lead cooled fast reactor. This coolant material serves a reliable choice with noticeable thermo-physical safety characteristics in terms of natural convection. Boussienesq approximation is resorted to appropriately reduce the governing partial differential equations (PDEs) for the fluid flow into a set of ordinary differential equations (ODEs). As a main contributing step, the coolant circulation speed is accordingly correlated to the loop operational power and temperature levels. Further temporal analysis and control synthesis activities may thus be carried out within a more consistent state space framework. Nyquist stability criterion is thereafter employed to carry out a sensitivity analysis for the system stability at various power and heat sink temperature levels and results confirm a widely stable natural circulation loop.

• 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.