• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.346-349
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• 2002

High Power and high dose ion implantation is essentially needed to make power MOSFET devices based on SiC wafers, because the diffusivities of the impurities such as Al, N, p, B in SiC crystal are very low. In addition, it is needed high temperature annealing for electrical activation of the implanted species. Due to the very high annealing temperature, the surface morphology after electrical activation annealing becomes very rough. We have found the different surface morphologies between implanted and unimplanted region. The unimplanted region showed smoother surface morphology It implies that the damage induced by high energy ion implantation affects the roughening mechanism. Some parts of Si-C bonding are broken in the damaged layer, s\ulcorner the surface migration and sublimation become easy. Therefore the macrostep formation will be promoted. N-type 4H-SiC wafers, which were Al ion implanted at acceleration energy ranged from 30kev to 360kev, were activated at 1600$^{\circ}C$ for 30min. The pre-activation annealing for damage relaxation was performed at 1100-1500$^{\circ}C$ for 30min. The surface morphologies of pre-activation annealed and activation annealed were characterized by atomic force microscopy(AFM).

• Journal of the Korean Home Economics Association
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• v.48 no.6
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• pp.83-101
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• 2010

Using the first wave of KLoSA(Korean Longitudinal study of Aging) beta version, this study analyzed factors affecting retirement adjustment by elapsed time from retiree's retirement through Binary Logit and Multinomial Logit Analysis. Participants were 1,780 retiree. The main results of this study were as follows : First, The retiree's education(-), health status(-), region(+), dwelling type(-), monthly household income(-), employment type before retirement(+), retirement reason(+), and the elapsed time from retirement(-) were affected whether they satisfied with pre-retirement or not. Second, The gender(-), age(-), and the region(+) were affected whether they satisfied with life after retirement or not. Third, The gender(-), age(-), education(+), heath status(+), dwelling type(+), monthly household income(+), retirement reason(-), and the elapsed time from retirement(+) were affected on their satisfaction after retirement compared to pre-retirement. Last, The different factors affected the life satisfaction after retirement by elapsed time from retirement.

• Journal of the Korean Ceramic Society
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• v.35 no.12
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• pp.1337-1342
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• 1998

To investigate an effect of phase separation on precipitation characteristics of ZnS microcrystals in ma-trix glass ZnS doped borosilicate glasses for nonlinear optical applications were prepared by melting and pre-cipitation process. ZnS dopant contributed to phase separation promotion which increased the phase separa-tion of the matrix glass within immiscibility region. It was also found that ZnS as phase separation promoter showed a similar contribution for some selected glass compositions in miscibility region. The precipitation of ZnS microcrystals occurred in thephase separable glass compoitions. The radius of ZnS microcrystals in-creased with increasing the heat treatment temperature and Na2O contents of matrix glass composition. The ZnS particle sizes estimated by effective mass approximation ranged from about 30 to 80${\AA}$ It was suf-ficiently small to show quantum confinement effect.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.4
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• pp.327-332
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• 2002

The main problems of computational complexity in object tracking are definition of objects, segmentations and identifications in non-structured environments with erratic movements and collisions of objects. The object's information as a region that corresponds to objects without discriminating among objects are considered. This paper describes the algorithm that, automatically and efficiently, recognizes and keeps tracks of interest-regions selected by users in video or camera image sequences. The block-based feature matching method is used for the region tracking. This matching process considers only dominant feature points such as corners and curved-edges without requiring a pre-defined model of objects. Experimental results show that the proposed method provides above 96% precision for correct region matching and real-time process even when the objects undergo scaling and 3-dimen-sional movements In successive image sequences.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.529-532
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• 1988

This paper proposes a graph matching algorithm based on simulated annealing, which assures the globally optimal solution for circuit partitioning for the placement in the rectilinear region occurring as a result of the pre-placement of some macro cells, or onto the nonplanar surface in some military or space applications. The circuit graph ($G_{C}$) denoting the circuit topology is formed by a hierarchical bottom-up clustering of cells, while another graph called region graph ($G_{R}$) represents the geometry of a planar rectilinear region or a nonplanar surface for circuit placement. Finding the optimal many-to-one vertex mapping function from $G_{C}$ to $G_{R}$, such that the total mismatch cost between two graphs is minimal, is a combinatorial optimization problem which was solved in this work for various examples using simulated annealing.

• Korean Journal of Child Education & Care
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• v.19 no.1
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• pp.117-127
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• 2019

Objective: The purpose of this study was a teacher efficacy scale for pre-service teacher and to examine the reliability and validity of the scale. Methods: Participants for this study were 428 pre-service teachers from G region. the data were analyzed using correlation, Cronbach's ${\alpha}$, Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA). Results: The pre-service teacher efficacy scale was consisted of 3 factors, 'efficacy for instructional strategies', 'efficacy for student engagement' and 'efficacy for classroom management' with 12 items. Cronbach's ${\alpha}$ was ranged from .72 to .82. The confirmatory factor analysis revealed that CMIN/DF = 1.59, RMSEA = .05, SRMR = .05, TLI = .96, CFI = .97. Conclusion/Implications: In conclusion, all these results show that the pre-service teacher efficacy scale is quite a reliability and validity.

• Journal of Families and Better Life
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• v.14 no.2
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• pp.171-171
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• 1996

The Purpose of this study is to find out factors which affect the expenditure on educations for children's human capital and to provide fundamental information to make a policy for education. Data are obtained from 2484 maried couples with children on the pre-school or over. The results of this study are as follows: 1) If the eldest child was in pre-school or public school, the expenditure on private education was higher than that of public education. While in the beyond junior high school, the expenditure on public education was much higher. 2) Life-cycle, the number of children, region, earned income, non-earned income, real assets, Engel's coeeficient were significant impact on the expenditure of education.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.1
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• pp.73.1-73.1
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• 2016

We present preliminary results of the submillimeter continuum observations of 14 Planck Galactic Cold Clumps (PGCCs), located in the ${\lambda}$ Orionis Complex. This region is the nearest large HII region, which is an ideal site for a study of the stellar feedback to its surroundings. We observed 14 PGCCs with JCMT/SCUBA-2 and used J=1-0 transitions of CO isotopologues from the PMO mapping observation. Several sub-clumps toward three PGCCs were detected at $850{\mu}m$. In order to examine whether these clumps can be candidates for pre-stellar cores, we compared each clump mass calculated from the $850{\mu}m$ continuum map to its Virial mass and Jeans mass calculated from the $^{12}CO$ and $C^{18}O$ (1-0) spectra, respectively. All clumps have masses smaller than their Virial and Jeans masses, indicating that none of them are gravitational bound and thus in the pre-stellar core stage. Also, the CO depletion factor, which has been derived from the dust continuum and the $C^{18}O$(1-0) line and can be an indicator of core evolution, toward the clumps is in the range of 1 to 5, suggesting that they are not very evolved dense pre-stellar cores. In addition, within individual PGCCs, we found clear gradients of velocity (${\sim}1km\;s^{-1}\;pc^{-1}$) and temperature (${\sim}10K\;pc^{-1}$) in the $^{13}CO$ (1-0) first moment map and the $^{12}CO$(1-0) excitation temperature map, respectively. This can be attributed to the compression and external heating by the HII region, which may prevent clumps from forming gravitationally bound structures and eventually disperse clumps. These results could be a hint about the negative effect of stellar feedback on core formation.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2002.05a
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• pp.35-40
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• 2002

In the present study, we examined the influence of prestrain on creep strength of Class M alloy(STS310S) and Class A(STS310J1TB) alloys containing precipitates. Prestrain was given by prior creep at a higher stress than the following creep stresses. Creep behaviour before and after stress change and creep rate of pre-strianed specimens were compared with that of virgin specimens. Pre-straining produced the strain region where the strain rate was lower than that of a virgin specimen both for STS310J1TB and STS310S steels. The reason for this phenomenon was ascribable to the viscous motion of dislocations, the interaction between dislocations and precipitates in a STS310J1TB steel, and the interaction of dislocations with sub-boundaries in a STS310S steel which has the higher dislocation density and smaller subgrain size resulted from pre-straining at higher stress.

• Bulletin of the Korean Chemical Society
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• v.30 no.3
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• pp.577-581
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• 2009

Interactions between the surface and capsid proteins of the hepatitis B virus (HBV) are critical for the assembly of virus particles. In this study, we developed a cell-based method to visualize the interactions between the capsid and surface proteins of HBV. Capsid-GFP, a capsid protein fused to a green fluorescence protein (GFP), forms nucleocapsid-like structures in the cytoplasm of mammalian cells. It relocates to the plasma membranes in cells expressing PH-PreS, a fusion protein consisting of the PreS region of the HBV surface protein and the PH domain of PLC-$\gamma$. Membrane localization of the capsid-GFP in these cells is prevented by an inhibitory peptide that blocks the interaction between the capsid and surface proteins. This dynamic localization of capsid-GFP is applicable for screening compounds that may potentially inhibit or prevent the assembly process of HBV particles.