• The Journal of the Acoustical Society of Korea
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• v.8 no.1
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• pp.23-30
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• 1989

Propagation phenomena of nonlinear pressure waves in a bubbly mixture are studied. The governing equations for a bubbly mixture are derived heuristically and energy equation is incorporated with other governing equations to take thermal effects into consideration inside the bubble. This non-isothermal condition of the bubble inside is especially important when high amplitude pressure waves are treated. Keller's equation is adapted for the bubble dynamics as practical problem. Some numerical simulations are carried out for the shock tube problem using a computer program based on the above model. A comparison with experimental results of Noordzij and van Wijngaarden shows that the structure of the wave in the shock tube experiment seems to be much more significantly affected 요 the complex heat transfer phenomena inside the bubbles than by the relative translational motion between bubbles and surrounding liquid.

• Journal of the Korea Society of Computer and Information
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• v.12 no.6
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• pp.89-96
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• 2007

Finite failure NHPP models presented in the literature exhibit either constant. monotonic increasing or monotonic decreasing failure occurrence rates per fault. Accurate predictions of software release times. and estimation of the reliability and availability of a software product require quality of a critical element of the software testing process : test coverage. This model called Enhanced non-homogeneous Poission process(ENHPP). In this paper, exponential coverage and S-type model was reviewed, proposes modified(the superosition and mixture) model, which make out efficiency application for software reliability. Algorithm to estimate the parameters used to maximum likelihood estimator and bisection method. model selection based on SSE statistics for the sake of efficient model, was employed.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.4
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• pp.33-38
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• 2009

This paper proposes an automatic equalizer control method in automobile audio system. The proposed method discriminates the music segment from the consecutive real-time audio stream of the radio and the equalizer is controlled automatically according to the classified genre of the music segment. For enhancing the accuracy of the music genre classification in real-time, timbre feature and rhythm feature extracted from the consecutive audio stream is applied to GMM(Gaussian mixture model) classifier. The proposed method evaluates the performance of the music genre classification, which classified various audio segments segmented from the audio signal of the radio broadcast in automobile audio system into one of five music genres.

• Preventive Nutrition and Food Science
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• v.22 no.1
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• pp.56-61
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• 2017

Rheological properties of waxy barley flour (WBF) dispersions mixed with various gums (carboxyl methyl celluleose, guar gum, gum arabic, konjac gum, locust bean gum, tara gum, and xanthan gum) at different gum concentrations were examined in steady and dynamic shear. WBF-gum mixture samples showed a clear trend of shear-thinning behavior and had a non-Newtonian nature with yield stress. Rheological tests indicated that the flow and dynamic rheological parameter (apparent viscosity, consistency index, yield stress, storage modulus, and loss modulus) values of WBF dispersions mixed with gums, except for gum arabic, were significantly higher than those of WBF with no gum, and also increased with an increase in gum concentration. In particular, konjac gum at 0.6% among other gums showed the highest rheological parameter values. Tan ${\delta}$ values of WBF-xanthan gum mixtures were lower than those of other gums, showing that there is a more pronounced synergistic effect on the elastic properties of WBF in the presence of xanthan gum. Such synergistic effect was hypothesized by considering thermodynamic compatibility between xanthan gum and WBF. These rheological results suggest that in the WBF-gum mixture systems, the addition of gums modified the flow and viscoelastic properties of WBF, and that these modifications were dependent on the type of gum and gum concentration.

• Korean journal of food and cookery science
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• v.12 no.1
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• pp.92-98
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• 1996

This experiment was carried out to investigate the effective additives and amount of addition in order to improve the quality of chou made with rice flour. The four emulsifiers and four thickeners were used as the additives in this test. The chou was formed with rice flour without the additives. There were not significantly differences in the sensory evaluation between choux of rice flour of non-additives and the additives, but the emulsifiers treatment increased the expansion capacity of paste. Thickeners did not improve the quality of choux. The hardness of pastes were increased and the cavities in choux were not formed in addition of high amount of thickeners. The mixture of two kinds of emulsifiers, the mixture of emulsifiers and a thickener did not improve of choux quality compared to the addition of emulsifier. The best quality of chou was obtained from 0.6% of lecithin.

• The Journal of the Acoustical Society of Korea
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• v.13 no.2E
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• pp.68-75
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• 1994

In many applications of signal processing, we have to deal with densities which are highly non-Gaussian or which may have Gaussian shape in the middle but have potent deviations in the tails. To fight against these deviations, we consider a finite mixture distribution for the speech excitation. We utilize the EM algorithm for the estimation of speech parameters and their enhancement. Robust Kalman filtering is used in the enhancement process, and a detection/estimation technique is used for parameter estimation. Experimental results show that the proposed algorithm performs better in adverse SNR input conditions.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.26 no.3
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• pp.288-294
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• 1990

Two pure fuel oils(#1 oil, #6 oil), theree pure alcohols (methanol, ethanol, propanol) were tested for the fuel characteristics such as miscibility (that established which pure fuels and fuel mixtures could be fired in the boiler), flash point, viscosity. Specific target of the study besides the oil/alcohols or oil/alcohol mixture without any modification and with safety. #1 oil could be mixed without any problems at all concentrations with two of the alcohols; these were the ethanol and propanol. However, miscibility of #6 oil with any alcohols and #1 oil with methanol was not possible and very limited in this study. The measurements of flash point and viscosity for the mixtures were done for the comparisons with the pure fuels. There was a marked change of flame shape and flame luminosity as the alcohol content of the mixtures was increased. The mixture flame shortened and became non-luminous compared with a pure fuel oil flame.

• Journal of computational fluids engineering
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• v.18 no.1
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• pp.13-21
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• 2013

Cavitating flow is usually formed on the surface of a high speed underwater object. When a object moves near a free surface at very high speed, the cavity signature becomes one of the major factors to be overcome by sensors of military satellite. The present work was to study the free surface effect on the ventilated cavitation. The governing equations were Navier-Stokes equations based on a homogeneous mixture model. The multiphase flow solver used an implicit preconditioning method in the curvilinear coordinate system. The cavitation model used here was the one first presented by Merkle et al.(2006) and redeveloped by Park & Ha(2009). Computations considered the free surface effects were carried out with a NACA0012 hydrofoil and the corresponding results were compared with the experimental data to have a good agreement. Calculations were then performed considering the ventilated cavitation, including the effect of non-condensable gas under the free surface effects.

• Journal of Korean Vacuum Science & Technology
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• v.5 no.2
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• pp.47-51
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• 2001

To obtain high remnant polarization and good crystalinity of ferroelectric thin films in non-volatile memory devices, the high temperature treatment in oxygen ambient is inevitable. Severe problems that occur in this process are oxygen diffusion into substrate, oxidation of electrode and buffer layer, degradation of microstructure and so on. We made ruthenium dioxide thin film by reactive sputtering with oxygen and argon mixture atmosphere. Comparing quantitatively the core-level spectra of Ru and RuO$_2$ obtained by x-ray photoelectron spectroscopy(XPS), we found that chemical state of RuO$_2$ is very stable and of good resistance to oxygen diffusion and oxidation of adjacent layers. It opens the use of RuO$_2$ thin film as a multifunctional layer of good conducting electrode and resistive barrier for the diffusion and the oxidation. We also suggest a correct understanding of Ru 3d core-level spectrum for RuO$_2$ based on the scheme of final state screening and charge transfer satellites.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.5
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• pp.1768-1772
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• 2010

Intra-molecular association is an important contribution to the overall hydrogen bonding in surfactant systems, especially in systems of colloidal and biological interest. Amphiphile systems, especially micelle and microemulsion systems, showed highly non-ideal behavior due to the intermolecular association and intra-molecular association. The objective of this research is to present a lattice fluid equation of state that combines the quasi-chemical nonrandom lattice fluid model with modified Veytsman statistics for intra + inter molecular association to calculate phase behavior for mixture containing surfactant systems. The lattice model could describe the literature data well for alkane and surfactant systems.