• Korean Journal of Child Education & Care
• /
• v.18 no.1
• /
• pp.77-102
• /
• 2018

The objectives of this study were to analyze the longitudinal mediation effects of maternal parenting stress and psychosocial development of infant on the influence of paternal involvement during infancy to children's peer interactions. For these objectives, latent growth modeling was used and adapted to the data taken from the Panel Study on Korean Children(PSKC), Wave I (0-year olds) to Wave III (2-year olds) and Wave V(4-year olds) to Wave VII(6-year olds). During a total of six years, 1,018 parent responded. The major results of this study were as follows. First, maternal parenting stress(initial status) had a significant mediating effect on the influence of paternal involvement(initial status) to children's play interaction(initial status). Second, maternal parenting stress(initial status/change rate) had a longitudinal mediating eff ect on the influence of paternal involvements(initial status/change rate) to children's play disruption-disconnection interactions(initial status/change rate). Third, psychosocial development of infants(initial status/change rate) had a longitudinal mediating effect on the influence of paternal involvement(initial status/change rate) to children's play interactions(initial status/change rate). Fourth, psychosocial development of infant(initial status) had a significant mediating effect on the influence of paternal involvement(initial status) to children's play disruption-disconnection interactions(initial status). The implications of the findings of the current study and suggestions for future research were also discussed.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.10 no.3
• /
• pp.254-261
• /
• 2005

The over-expression of Bcl-2 has greatly improved the culture period, specific growth rate, and maximum viable cell density of NS0 cells culture under low serum condition. Further analysis of these data suggests that a saturation model of the Monod type can be used to represent the relationships of specific growth rate and initial serum concentration. The ${\mu}_{max}$ and $K_s$ for the Bcl-2 cell line is $0.927day^{-1}\;and\;0.947\%(v/v)$ respectively, which are $21\%$ greate and $7\%$ lower respectively than its control counterpart. Study on the amino acid supplementation revealed that Bcl-2 cell lines possess greater improvement in the specific growth rate and maximum viable cell density compared to the control cell lines. A further increase in the amino acid supplementation has resulted a $17\%$ decrease in specific growth rate and no improvement in maximum viable cell density in the control culture. However, the Bcl-2 cell line exhibited a better growth characteristic in this culture condition compared to that of control cell lines. The higher specific growth rate and maximum viable cell density of the Bcl-2 cell line in medium fortified with serum and MEM EM suggested a more efficient nutrient metabolism compared to that in the control cell line. The low serum and amino acid utilisation rate and the higher cell yield may prove to be important in the development of serum/protein free culture.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 1998.03a
• /
• pp.178-183
• /
• 1998

This paper examines the crack growth behavior of 7075-T651 and 5052-H32 aluminum alloys for variable load within tensile load range condition. The cantilever beam type specimen with a chevron notch is used in this study. The crack growth and closure are investgated by compliance method. The applied initial stress ratio is R=0.3 and variable load are R=0.65, 0.46. Crack length, stress intensity factor range, ratio of effective stress intensity factor range and crack growth rate etc. are inspected with fracture mechanics estimate.

• Journal of the Korean Society of Safety
• /
• v.15 no.3
• /
• pp.57-65
• /
• 2000

The stress corrosion crack growth is simulated assuming a small axial surface crack inside a S/G tube. Internal pressure and residual stresses are considered as applied forces. Stress intensity factors along crack front, variation of crack shape and crack growth rate are obtained and discussed. It is noted that the aspect ratio of the crack is not depend on the initial crack shape but depend on the residual stress distribution.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.20 no.1
• /
• pp.117-129
• /
• 2017

This research was conducted to construct a tree belt around Saemangeum reclaimed land using various planting methods and to analyze initial growth amount, to provide practical data to construct tree belt of various purposes. Tree species used in tree belt construction were Pinus thunbergii and Quercus serrata, and the main planting treatment methods used were categorized by existence of windy fence, mixed planting, and un-mixed planting. Growth amount analysis was conducted using ANOVA to compare growth amounts in different experimental groups and Duncan's multiple range test. Growth amount analysis results of tree belt by planting method showed that it is most statistically plausible to install 50% porous windy fence from the direction of wind and frost, followed by planting P. thunbergii and Q. serrata in areas that require mixed tree species tree belt around Saemangeum reclaimed land. In areas where un-mixed planting tree belt is required, it was appropriate to use P. thunbergii alone without a windy fence. Lastly, if the purpose of the tree belt is limited to rapid growth, it was most ideal to plant P. thunbergii alone (without windy fence) or install 50% porous windy fence from the direction of wind and frost, followed by planting P. thunbergii and Q. serrata. This research is based on initial growth amount of tree belt and there is a need for a long-term monitoring of tree belt growth to increase tree-planting success rate in establishing tree belt according to Saemangeum internal development.

• Journal of Applied Reliability
• /
• v.15 no.2
• /
• pp.90-100
• /
• 2015

Reliability growth rate (or reliability growth curve slope) have the two cases of trend as a constant or changing one during the reliability growth testing. The changing case is very common situation. The reasons of reliability growth rate changing are that the failures to follow the NHPP (None-Homogeneous Poisson Process), and the solutions implemented during test to break out other problems or not to take out all of the root cause permanently. If the changing were big, the "Goodness of Fit (GOF)" of reliability growth curve to test data would be very low and then reduce the accuracy of assessing result with test data. In this research, we are using Duane model and AMSAA model for assessing test data and projecting the reliability level of complex and repairable system as like construction equipment and vehicle. In case of no changing in reliability growth rate, it is reasonable for reliability engineer to implement the original Duane model (1964) and Crow-AMSAA model (1975) for the assessment and projection activity. However, in case of reliability growth rate changing, it is necessary to find the method to increase the "GOF" of reliability growth curves to test data. To increase GOF of reliability growth curves, it is necessary to find the proper parameter calculation method of interesting reliability growth models that are applicable to the situation of reliability growth rate changing. Since the Duane and AMSAA models have a characteristic to get more strong influence from the initial test (or failure) data than the latest one, the both models have a limitation to contain the latest test data information that is more important and better to assess test data in view of accuracy, especially when the reliability growth rate changing. The main objective of this research is to find the parameter calculation method to reflect the latest test data in the case of reliability growth rate changing. According to my experience in vehicle and construction equipment developments over 18 years, over the 90% in the total development cases are with such changing during the developing test. The objective of this research was to develop the newly assessing method and the process for GOF level increasing in case of reliability growth rate changing that would contribute to achieve more accurate assessing and projecting result. We also developed the new evaluation method for GOF that are applicable to the both models as Duane and AMSAA, so it is possible to compare it between models and check the effectiveness of new parameter calculation methods in any interesting situation. These research results can reduce the decision error for development process and business control with the accurately assessing and projecting result.

• Microbiology and Biotechnology Letters
• /
• v.20 no.4
• /
• pp.371-376
• /
• 1992

The growth and cultural characteristics of Bacillus sp. SH-8 and SH-8M were investigated at various pH conditions. Bacillus sp. SH-8 showed normal growth pattern above pH 9.0. However, with the pH adjusted below 7.7, 0.$D_{550}$ decreased rapidly with concomitant reduction in viable cell numbers. In contrast, Bacillus sp. SH-8M demonstrated growth capability at pH 7.7, but with slightly reduced growth rate at pH 6.9. Similar results were obtained when those two strains were cultivated on the solid medium. Both of them showed short rod shapes at pH 10.2. However, at pH 7.7 only Bacillus sp. SH-8 was observed to have elongated rod shape. Extracellular pH of both the strains, when cultured at initial pH of 10.2, reached to 9.0 after the incubation of 28 hours. At the initial pH of 9.0 and 9.6, the extracellular pH was reduced at the beginning of cultivation, but elevated after 12 hours. When cultured at initial pH of 6.9 and 7.7, extracelluar pH of Bacillus sp. SH-8M increased to 8.0 and 8.7, respectively, while that of Bacillus sp. SH8 remained constant pH 7.0. The highest sporulation rate of Bacillus sp. SH-8 and SH-8M was obtained at the initial pH of 10.2 and after the incubation of 3 days with the sporulation rate of 95% and 85%, respectively.

• Journal of Environmental Science International
• /
• v.6 no.5
• /
• pp.481-488
• /
• 1997

Microorganisms capable of degrading trlchloroethylene(TCEI using phenol as a induction substrate were isolated from industrial effluents and soil. The strain MS-64K which had the highest blodegradablllty was identified as the genus Micrococcus. The optimal conditions of medium for the growth and blodegadatlon of trlchloroethylene were observed as follows; the initial pH 7.0, trlchloroethylene 1, 000ppm as the carbon source, 0.2% ${(NH_4)}_2SO_4$, as the nitrogen source. respectively. Lag period and degradation time on optimal medium were shorter than those on Isolation medium. Growth on the optimal medium was Increased. Addition of 0.1% Triton X-100 Increased the growth rate of Micrococcus sp. MS-64K, but degradation was equal to optimal medium. Trlchloroethylene degradation by Micrococcus sp. MS-64K was shown to fit logarithmic model when the compound was added at initial concentration of 1, 000ppm.

• Korean Journal of Child Studies
• /
• v.26 no.1
• /
• pp.183-202
• /
• 2005

This study performed intensive indicators based on a model of economics of education. Trends of childcare in Korea were obtained by producing values developed with statistical data. Results showed that such simple initial indicator values as numbers of children, institutions and teachers have improved. However, intensive indicator values that take demographic and economic conditions into consideration have not reached the same rate of progress as the initial indicator values. In other words, qualitative growth remains at an unsatisfactory level in comparison to quantitative growth and to qualitative growth in members of the Organization for Economics Cooperation and Development (OECD).Thus, financial investment by the government should be expanded in order to reach the desired level of high quality in daycare for children.

• Journal of the Korean Ceramic Society
• /
• v.34 no.5
• /
• pp.483-490
• /
• 1997

Al2O3/metal composites were fabricated by oxidation and reaction of molten Al-alloy into two types of commercial Al2O3-SiO2 fibrous insulation board. The growth rate, composition and microstructure of these materials were described. An AlZnMg(7075) alloy was selected as a parent alloy. Mixed polycrystalline fiber and glass phase fiber were used as a filler. The growth surface of an alloy was covered with and without SiO2. SiO2 powder was employed as a surface dopant to aid initial oxidation of Al-alloy. Al-alloy, SiO2, fiber block and growth inhibitor CaSiO3 were packed sequentially in a alumina crucible and oxidized in air at temperature range 90$0^{\circ}C$ to 120$0^{\circ}C$. The growth rate of composite layer was calculated by measuring the mass increasement(g) per unit surface($\textrm{cm}^2$). XRD and optical microscope were used to investigate the composition and phase of composites. The composite grown at 120$0^{\circ}C$ and with SiO2 dopant showed rapid growth rate. The growth behavior differed a little depending on the types of fiber used. The composites consist of $\alpha$-Al2O3, Al, Si and pore. The composite grown at 100$0^{\circ}C$ exhibited better microstructure compared to that grown at 120$0^{\circ}C$.