• Journal of the Society of Naval Architects of Korea
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• v.41 no.5
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• pp.8-13
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• 2004

In order to better understand the characteristics of the flow field around the submerged hydrofoil of finite span with high speed and shallow submergence. a numerical code which can solve the flow around a fast lifting body under the free surface was developed and used to obtain various interesting features of the flow. The code was based on the panel method of Hess( 1972), and the free surface condition was linearized to conform with the assumption of the high Froude number. It is shown that the effect of the change of submerged depth. angle of attack and aspect ratio upon the sectional lift coefficient is rather significant for the case of the chosen example wing, which has the rectangular planform. Since Lee(2002)'s theoretical results were for the wing of elliptical planform, the direct comparison of the two results was not possible. It seems that more computational results are in need to compare the theoretical and the numerical prediction in detail.

• Solar Energy
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• v.15 no.3
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• pp.91-103
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• 1995

Non-gray radiation with convection in the entrance region of a smooth tube is numerically investigated. The fluid is a mixture of carbon dioxide, water vapor, and nitrogen to simulate combustion products of propane. The flow is assumed to be laminar and hydrodynamically and thermally developing. The P-1 approximation is used to simplify the radiative transfer equation and the exponential wide band model is adapted to model the spectral absorption coefficients of non-gray gas mixture. The bulk mean temperature and Nusselt number variation along the tube axis are shown for several inlet and wall temperature pairs to show the effect of temperature on the heat transfer characteristics. Nusselt numbers for simultaneously developing flow are compared to those for thermally developing flow. In addition, the effect of the mole fraction of the non-gray gases on convective and radiative Nusselt numbers is investigated.

• Journal of Biomedical Engineering Research
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• v.18 no.4
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• pp.499-505
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• 1997

A non-invasive technique to measure absorption and scattering coefficients was investigated The reflected backscattered light from the surface of phantom and biological tissue was obtained by using a time-correlated single photon counting system in pico-second time domain. The absorption and scattering coefficients were acquired by the time of peak and asymptotic behavior of the time-resolved reflectance curve and agreed well the ones that is obtained with deconvolution method It was found that the approximation method was good for biological medium to calculate optical properties due to its convenience and accuracy.

• Proceedings of the Korea Contents Association Conference
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• 2016.05a
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• pp.383-384
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• 2016

The Special Needs Education Assessment Tool (SNEAT) were verified of reliability and validity. However, the reliability and validity has been verified is only Okinawa Prefecture, the national data has not been analyzed. Therefore, this study aimed to verify the reliability and construct validity of SNEAT in Miyagi Prefecture as part of the national survey. SNEAT using 55 children collected from the classes on independent activities of daily living for children with disabilities in Miyagi Prefecture between November and December 2015. Survey data were collected in a longitudinal prospective cohort study. The reliability of SNEAT was verified via the internal consistency method; the coefficient of Cronbach's ${\alpha}$ were over 0.7. The validity of SNEAT was also verified via the latent growth curve model. SNEAT is valid based on its goodness-of-fit values obtained using the latent growth curve model, where the values of comparative fit index (0.997), tucker-lewis index (0.996) and root mean square error of approximation (0.025) were within the goodness-of-fit range. These results indicate that SNEAT has high reliability and construct validity.

• Proceedings of the Korea Contents Association Conference
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• 2016.05a
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• pp.387-388
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• 2016

Kwon (2015) was developed Employment Promotion Tool for Persons with Disabilities in the Aspect of the Quality of Life(QOL-EPAT). But its reliability and validity have not been verified yet. Therefore, this study aimed to verify the reliability, content validity and construct validity of QOL-EPAT. This study was conducted with a disability employment specialists. Period May to October 2015, six months, was distributed to collect the questionnaire. Reliability of QOL-EPAT was estimated using the internal consistency method; both the coefficient of Cronbach's ${\alpha}$ were over 0.7. Construct Validity; Construct validity was verified using structural equation modeling (SEM). Goodness of fit index (GFI), Adjusted goodness of fit index (AGFI), comparative fit index (CFI), tucker-Lewis index (TLI) and root mean square error of approximation (RMSEA) are the suitability indices of SEM. As the result, GFI=0.898; AGFI=0.844; CFI=0.961; TLI=0.949 and RMSEA=0.069. The validity was verified because the values of GFI, AGFI, CFI, TLI and RMSEA were within the goodness-of-fit range. Thus, impaired employs promoters of Japan also provided which allows for analysis of the policy by using a validated scale.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.6
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• pp.1302-1309
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• 2014

In this paper, we propose a method to improve the performance of the direction-of-arrival (DOA) estimation of a speech source using a multiple signal classification (MUSIC)-based algorithm. Basically, the proposed algorithm utilizes a complex coefficient band pass filter to generate the narrow band signals for signal analysis. Also, reverberation component reduction and quadratic function-based response approximation in MUSIC spatial spectrum are utilized to improve the accuracy of DOA estimation. Experimental results show that the proposed method outperforms the well-known generalized cross-correlation (GCC)-based DOA estimation algorithm in the aspect of the estimation error and success rate, respectively.Abstract should be placed here. These instructions give you guidelines for preparing papers for JICCE.

• Journal of The Korean Astronomical Society
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• v.47 no.5
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• pp.187-193
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• 2014

Recent cosmological observations indicate that the reionized universe may have started at around z = 6, where a significant suppression around $Ly{\alpha}$ has been observed from the neutral intergalactic medium. The associated neutral hydrogen column density is expected to exceed $10^{21}cm^{-2}$, where it is very important to use the accurate scattering cross section known as the Kramers-Heisenberg formula that is obtained from the fully quantum mechanical time-dependent second order perturbation theory. We present the Kramers-Heisenberg formula and compare it with the formula introduced in a heuristic way by Peebles (1993) considering the hydrogen atom as a two-level atom, from which we find a deviation by a factor of two in the red wing region far from the line center. Adopting a representative set of cosmological parameters, we compute the Gunn-Peterson optical depths and absorption profiles. Our results are quantitatively compared with previous work by Madau & Rees (2000), who adopted the Peebles approximation in their radiative transfer problems. We find deviations up to 5 per cent in the Gunn-Peterson transmission coefficient for an accelerated expanding universe in the red off-resonance wing part with the rest wavelength ${\Delta}{\lambda}{\sim}10{\AA}$.

• Electrical & Electronic Materials
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• v.7 no.5
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• pp.389-396
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• 1994

The bilayer film of Ag/a-S $e_{75.G}$ $e_{25}$ and the monolayer film of a-S $e_{75.G}$ $e_{25}$ act as a negative-type and a positive-type resist in focused ion beam lithography, respectively. Using a model which takes into account the ion stopping power, the ion projected range, the ion concentration implanted into resists and the ion transmission coefficient, etc., the ion resist parameters are calculated for a broad range of ion energies and implanted doses. Ion sources of A $r^{+}$, S $i^{++}$ and G $a^{+}$ are used to expose resists. As the calculated results, the energy loss per unit distance by Ga'$^{+}$ ion is about 10$^{3}$[keV/.mu.M] and nearly constant for all energy range. Especially, the projected range and struggling for 80[keV] G $a^{+}$ ion energy are 0.0425[.mu.m] and 0.020[.mu.m], , respectively and the resist thickness of a-S $e_{75}$ G $e_{25}$ to minimize the ion penetration rate into a substrate is 0.118[.mu.m].u.m]..u.m].

• The KIPS Transactions:PartA
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• v.13A no.3 s.100
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• pp.267-274
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• 2006

This paper describes a method to achieve different level of detail for the given volumetric data by assigning weight for the given data points. The relation between wavelet transformation and alpha shape was investigated to define the different level of resolution. Scattered data are defined as a collection of data that have little specified connectivity between data points. The quality of interpolant in volumetric trivariate space depends not only on the distribution of the data points in ${\Re}^3$, but also on the data value (intensity). We can improve the quality of an approximation by using wavelet coefficient as weight for the corresponding data points.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.53 no.2
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• pp.65-69
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• 2004

This paper calculates and gives the analysis of electron swarm transport coefficients as described electric conductive characteristics of pure Ar, pure $SiH_4$, Ar-$SiH_4$ mixture gases($SiH_4$-0.5%, 2.5%, 5%) over the range of E/N = 0.01~300[Td], P = 0.1, 1, 5.0 [Torr] by Monte Carlo the backward prolongation method of the Boltzmann equation using computer simulation without using expensive equipment. The results have been obtained by using the electron collision cross sections by TOF, PT, SST sampling, compared with the experimental data determined by the other author. It also proved the reliability of the electron collision cross sections and shows the practical values of computer simulation. Electron swann parameters in argon were drastically changed by adding a small amount of mono-silane. The electron drift velocity in these mixtures showed unusual behaviour against E/N. It had negative slope in the medium range of E/N, yet the slope was not smooth but contained a small hump. The longitudinal diffusion coefficient also showed a corresponding feature in its dependence on E/N. A two-tenn approximation of the Boltzmann equation analysis and Monte Carlo simulation have been used to study electron transport coefficients.