• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.158-161
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• 2008

In the line array roll set (LARS) process, the initial plate is progressed into the final shape in a stepwise or pathwise manner according to the basic principle of the incremental forming process. The deformation proceeds simultaneously in the longitudinal and transverse directions. It was found that the curvature level of the formed plates in the previous study was well over the curvature required in shipyards. This fact shows that the LARS method has considerable potential for shipbuilding applications. In this study, several experiments with the LARS system is carried out fur manufacturing of plates with large curvatures. The bulbs at a stem and stern among ship hull plates correspond to these plates. Furthermore, the qualities of formed plates are evaluated according to the types of roll arrangements through experimental and numerical analyses.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.1
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• pp.61.2-61.2
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• 2014

We present a set of fiducial sequences of horizontal-branch stars in bright Galactic globular clusters, which have previously been observed in the Sloan Digital Sky Survey (SDSS). We derive fiducial lines on color-magnitude diagrams in multiple color indices (g - r, g - i, g - z, and u - g), after rejecting foreground and background objects as well as RR Lyrae variables utilizing these color indices. We compare our fiducial sequences with model predictions from Yonsei-Yale evolutionary tracks and BaSel spectral libraries, and find a satisfactory agreement between them in terms of their color-magnitude relations, except in u - g. We also compare theoretical models to color-magnitude diagrams of two open clusters (M67 and NGC 6791). Based on our best available cluster distance and reddening, we find that the mass of red clump (RC) stars in NGC 6791 is about a factor of two smaller than an earlier estimate from the application of asteroseismic scaling relations for solar-like oscillations. The smaller RC mass implies an enhanced mass loss along the red giant branch, which is in accordance with other compelling evidences found in this metal-rich system. Our estimated luminosity of RC stars in NGC 6791 is about 0.2 mag fainter than in earlier investigations based on solar-metallicity calibrations, and results in ~10% reduction in the RC-based distance estimation, when applied to metal-rich systems such as in the Galactic bulge.

• Clean Technology
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• v.13 no.2
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• pp.122-126
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• 2007

When ammonia ($NH_3$) gas was supplied to a biofilter packed with bio-carrier made of waste polyurthane and worm cast. No odor gases were detected at the outlet of the biofilter when $NH_3$ gas was supplied to the biofilter at the space velocity(SV) of $50\;h^{-1}$ until the inlet $NH_3$ concentration increased to $4\;{\sim}\;454\;ppmv$. The gradual inlet $NH_3$ concentration was set and the removal efficiency of $NH_3$ gas was measured at each condition, while the SV of $NH_3$ increased step by step from 100 to $400\;h^{-1}$. The maximum possible inlet $NH_3$ loading was $11.38\;g-NH_3{\cdot}m^{-3}{\cdot}h^{-1}$ and $34.42\;g-NH_3{\cdot}m^{-3}{\cdot}h^{-1}$ while maintaining the removal efficiency of 100% when the SV was $50\;h^{-1}$ and $100 \;h^{-1}$, respectively. The maximum $NH_3$ loading was $71.28 \;g-NH_3{\cdot}m^{-3}{\cdot}h^{-1}$ with the $NH_3$ removal efficiency of 99.85% at SV $300\;h^{-1}$.

• BMB Reports
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• v.29 no.3
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• pp.272-275
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• 1996

The expression of genes induced by Dichloroacetate (DCA) treatment was analyzed by mRNA differential display. Purified total RNAs from rat liver treated with saline or DCA (100 mg/100 g b.w.) were reverse transcribed by using a set of oligonucleotide primers. The PCR products were resolved on a denaturing sequencing gel. PCR band representing mRNA expressed specifically in DCA-treated liver was excised and reamplified by PCR. A 120-bp c-DNA clone named IC1 was isolated and the DNA sequence of IC1 was analyzed. IC1 revealed 50% homology with 3' end of a mouse fibroblast growth factor mRNA This result indicates that DCA induces the expression of a gene which has a 50% homology with a Mouse fibroblast growth factor, and expression of this gene might be involved in non genotoxic process caused by DCA.

• Journal of the Korean Mathematical Society
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• v.45 no.2
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• pp.493-511
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• 2008

In this article, we study the relations of horizontally homothetic harmonic morphisms with the stability of totally geodesic submanifolds. Let $\varphi:(M^n,g)\rightarrow(N^m,h)$ be a horizontally homothetic harmonic morphism from a Riemannian manifold into a Riemannian manifold of non-positive sectional curvature and let T be the tensor measuring minimality or totally geodesics of fibers of $\varphi$. We prove that if T is parallel and the horizontal distribution is integrable, then for any totally geodesic submanifold P in N, the inverse set, $\varphi^{-1}$(P), is volume-stable in M. In case that P is a totally geodesic hypersurface the condition on the curvature can be weakened to Ricci curvature.

• Journal of the Korean Mathematical Society
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• v.51 no.4
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• pp.655-663
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• 2014

Let R be a ring with identity, X(R) the set of all nonzero, non-units of R and G(R) the group of all units of R. We show that for a matrix ring $M_n(D)$, $n{\geq}2$, if a, b are singular matrices of the same rank, then ${\mid}o_{\ell}(a){\mid}={\mid}o_{\ell}(b){\mid}$, where $o_{\ell}(a)$ and $o_{\ell}(b)$ are the orbits of a and b, respectively, under the left regular action. We also show that for a semisimple Artinian ring R such that $X(R){\neq}{\emptyset}$, $$R{{\sim_=}}{\oplus}^m_{i=1}M_n_i(D_i)$$, with $D_i$ infinite division rings of the same cardinalities or R is isomorphic to the ring of $2{\times}2$ matrices over a finite field if and only if ${\mid}o_{\ell}(x){\mid}={\mid}o_{\ell}(y){\mid}$ for all $x,y{\in}X(R)$.

• Advances in aircraft and spacecraft science
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• v.10 no.4
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• pp.317-334
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• 2023

This paper presents a basic methodology and a set of numerical tools for the preliminary design of solid-fueled ramjet missiles. An elementary code determines the baseline system configuration comprised of warhead, guidance-control, and propulsion masses and geometries from specific correlations found in the literature. Then, the system is refined with the help of external and internal ballistics codes. Equations of motion are solved for the flight's ascending, cruising, and descending stages and the internal ballistic set of equations designs the ramjet engine based on liquefying fuels. The combined tools sized the booster and the ramjet sustainer engines for a long-range missile, intended to transport 200 kg of payload for more than 300 km range flying near 14,000 m altitude at Mach 3.0. The refined system configuration had 600 mm in diameter and 8,500 mm in length with overall mass of 2,128 kg and 890 kg/m3 density. Ramjet engine propellant mass fraction was estimated as 74%. Increased missile range can be attained with paraffin-polyethylene blend burning at near constant regression rate through primary air mass flow rate control and lateral 2-D air intakes.

• Bioinformatics and Biosystems
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• v.1 no.1
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• pp.67-72
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• 2006

The aim of this paper is to discuss the effect of missing values in detecting differentially expressed genes in a cDNA microarray experiment in the context of a one sample problem. We conducted a cDNA micro array experiment to detect differentially expressed genes for the metastasis of colorectal cancer based on twenty patients who underwent liver resection due to liver metastasis from colorectal cancer. Total RNAs from metastatic liver tumor and adjacent normal liver tissue from a single patient were labeled with cy5 and cy3, respectively, and competitively hybridized to a cDNA microarray with 7775 human genes. We used $M=log_2(R/G)$ for the signal evaluation, where Rand G denoted the fluorescent intensities of Cy5 and Cy3 dyes, respectively. The statistical problem comprises a one sample test of testing E(M)=0 for each gene and involves multiple tests. The twenty cDNA microarray data would comprise a matrix of dimension 7775 by 20, if there were no missing values. However, missing values occur for various reasons. For each gene, the no missing proportion (NMP) was defined to be the proportion of non-missing values out of twenty. In detecting differentially expressed (DE) genes, we used the genes whose NMP is greater than or equal to 0.4 and then sequentially increased NMP by 0.1 for investigating its effect on the detection of DE genes. For each fixed NMP, we imputed the missing values with K-nearest neighbor method (K=10) and applied the nonparametric t-test of Dudoit et al. (2002), SAM by Tusher et al. (2001) and empirical Bayes procedure by $L\ddot{o}nnstedt$ and Speed (2002) to find out the effect of missing values in the final outcome. These three procedures yielded substantially agreeable result in detecting DE genes. Of these three procedures we used SAM for exploring the acceptable NMP level. The result showed that the optimum no missing proportion (NMP) found in this data set turned out to be 80%. It is more desirable to find the optimum level of NMP for each data set by applying the method described in this note, when the plot of (NMP, Number of overlapping genes) shows a turning point.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.2
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• pp.72-82
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• 2005

The objective of this paper is to describe the optimization of design parameters in a large-sized commercial bus heater system by using CFD(computational fluid dynamics) analysis and Taguchi method. In order to obtain the best combination of each control factor which results in a desired performance of heater system, the parameter design of the Taguchi method is adopted for the robust design considering the dynamic characteristic. The research activity may be divided into four phases. The first one is analyzing the problem, i.e., ascertaining the influential factors. In the second phase the levels were set in such a way that their variation would significantly influence the response. In the third phase the experimental runs were designed. In the final phase the planned runs were carried out numerically to evaluate the optimal combination of factors which is able to provide the best response. In this study, eight factors were considered for the analysis: one with two level and seven with three level combinations comprising the $L_{18}(2^1{\times}3^7)$ orthogonal array. The results of this study can be summarized as follows ; (i)The optimum condition of control factor is a set of <$A_2\;B_1\;C_3\;D_3\;E_1\;F_2\;G_3\;H_2$> where A is shape of the outer fin, B is pitch of the outer fin, C is height of the outer fin, D is the inner fin number, E is the inner fin height, F is length of the flame guide, G is diameter of the heating element and H is clearance between air guide and heating element. (ii)The heat capacity of heated discharge air under the optimum condition satisfies the equation y=0.6M w here M is a signal factor. (iii)The warm-up rate improves about three times, more largely as com pared with the current condition, which results in about 9.2minutes reduction.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.52 no.3
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• pp.183-190
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• 2016

This study carried out an experiment to find out the reaction of hairtail, Trichinus lepturus to the colors of LED light as a basic study on the development of the trolling gear and a method to enable the day-night operation. We used hairtails caught around Seongsan-po, Jeju Island by set nets and hairtail angling. The seven hairtails of the average length 68.9 cm (SD 9.2 cm) and the average weight 135.9 g (SD 47.9 g) were adapted themselves in the experimental water tank, 15 m Self-Governing 1.7 m in height and 1.5 m in depth, and then they were studied. We conducted experiment at the Ocean and Fisheries Research Institute in Jeju Special Self-Governing Province, from November to December 2015, and the sea surface temperature was between 16.5 and $19.5^{\circ}C$. The four colors of LED light, blue, white, green and red, were set up to transmit downward from the marginal area of tank. The 1 meter depth light intensity of LED colors is as follows: $0.09w/m^2/s$ (blue), $0.18w/m^2/s$ (white), $0.04w/m^2/s$ (green) and $0.007w/m^2/s$(red) To know the optimum LED color light, we selected one with better reaction rate after comparison of two colors simultaneously and the selected color was again compared to the other color in a tournament style two times a day (day and night) and ten times totally. The reaction rates were shown as the frequencies of hairtail appearance for 5 minutes in the lighting zone after turning on the LED lights. The reaction rate of the blue was at 97% unlike the red 3% (p < 0.001). The blue was at 75% unlike the green at 25% (p < 0.001). The blue was at 67% unlike the white at 33% (p < 0.001). Therefore, the color of light source showing the highest reaction rate was the blue.