• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 1992.11a
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• pp.267-275
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• 1992

비선형 체계의 상태 추정량은 H4Z(Ducan - Mortensen - Zakai) 방정식(Runggaldier, Spizzichino: 1987)의 해를 구함으로써 얻어 진다. 일반 비선형 체계의 DMZ 방정식의 해를 구하기는 어렵다. 계산 가능한 "유한 차원"의 DMZ 방정식의 해를 제공하는 체계의 족(class)은 이론 및 실제 응용에 중요하다. 본 연구에서는"마코비안 도약 선형 체계(Marcovian Jump Linear System: MJLS)"의 DMZ 방정식이 유한 차원의 해를 가지는 것을 증명하였다.

• School Mathematics
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• v.17 no.3
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• pp.407-421
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• 2015

Linear system is a basic subject matter of school mathematics courses. Even though elimination is a useful method to solve linear systems, its fundamental principles were not discussed pedagogically. The purpose of this study is to help the development of mathematical content knowledge on linear systems conceptions. To do this, various representations and translations among them were considered, and in particular, the basic principles for elimination method are analyzed geometrically. Rectangular representation is used to solve word problem treated in numbers of things in elementary mathematics and it is useful as a pre-stage to introduce elimination. Slopes and intercepts of lines associated linear equations are used to obtain the Cramer's formula and this solving method was showing the connection between algebraic and geometric procedures. Strategy deleting variables of linear systems by elementary operations is explored and associated with the movements of lines in the family of lines passing through a fixed point. The development of mathematical content knowledge is expected to enhance pedagogical content knowledges.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.651-652
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• 2010

• Journal of Educational Research in Mathematics
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• v.14 no.3
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• pp.305-325
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• 2004

This study is on the teaching-learning of parameter concept in secondary school mathematics. In our school mathematics curriculum, parameter concept is explicitly presented at high school mathematics textbook. But student have difficulty in understanding parameter concept because this concept is implicitly used in the textbook from 7-grade mathematics. Moreover, it is true that mathematics teacher give a little attention to student's understanding of parameter con- cept. In this study, we analyzed concept definition of parameter and the extension of parameter on the basis of preceding research, our mathematical curriculum, mathematical dictionaries. After that, we concluded that parameter is explicitly called in t where x= f(t), y= g(t) and parameter is implicitly treated in the learning of relation between quantities in our mathematical curriculum. We pointed to the importance of parameter concept in the successful learning of school algebra. Specially, when the level of algebra is in the learning of relation between quantities, parameter is the key concept for understanding and representing of families of equations or functions. In mathematics class, students have opportunity to reflect that what the role of each variable(parameter, dependent variable, independent variable etc.) is, and where the information which determines it comes from. It is for mathematical communications as well as learning school algebra. Therefore, mathematics teacher's didactical attention is more needed to student have a good concept image of parameter before they learn explicitly its concept definition.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.8
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• pp.474-481
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• 2018

The purpose of this study was to examine the mediating effects of maternal family experience on the relationship between mothers' tendency to addicted to smartphones and the social competence of young children. The subjects of this study were 481 mothers who delivered infants to a kindergarten or daycare center in Jeju area After conducting the questionnaire, the results of the responses were analyzed. To analyze the collected data, structural equations were implemented using SPSS Statistic 18.0 program. The results of this study are summarized as follows. First, the correlational analysis showed that the tendency of the addiction of smartphone and the social ability of the infant showed a significant correlation with the mother's family experience. Second, in the relationship between the mother's smartphone tendency and the social competence of the infant, The research model and the competition model were set up to examine the mediating effect and the competition model was found to be more appropriate. As a result, it can be seen that mother's original family experience is partly mediated in relation to mother's tendency to add to smartphone and social competence of infant. Based on these results, the implications of this study and suggestions for subsequent research were discussed.

• Composites Research
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• v.17 no.4
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• pp.25-31
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• 2004

In this study, a refined beam analysis model has been developed for multi-celled composite blades with elliptic cross-sections. Reissner's semi-complimentary energy functional is introduced to describe the beam theory and also to deal with the mixed-nature of the formulation. The wail of elliptic sections is discretized into finite number of elements along the contour line and Gauss integration is applied to obtain the section properties. For each cell of the section, a total of four continuity conditions are used to impose proper constraints for the section. The theory is applied to single- and double-celled composite blades with elliptic cross-sections and is validated with detailed finite element analysis results.

• Journal of the Korean Home Economics Association
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• v.41 no.8
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• pp.139-158
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• 2003

This study investigated the effects of Korean parents' family-of-origin experiences, marital conflict, open or dysfunctional communication with their children, children's coping behaviors on their behavior problems as a function of a child's sex. Theoretical models for both sexes were constructed based on the results. Two hundred and nine boys and one hundred and ninety six girls of 4th and 5th grades from two elementary schools filled out the questionnaires to assess their communication with the parents, their problem-focused coping behaviors, and their internalizing and externalizing behavior problems. Four hundred five parents of these children answered the questionnaires to assess differentiation for the family-of-origin and the marital conflict. The results were as follows. Boys' path pattern showed that the fathers' differentiation from the family-of-origin effected their sons' internalizing and externalizing behavior problems through parent-child dysfunctional communication. Girls' path exhibited two different patterns. One is that the mothers' differentiation from the family-of-origin effected their daughters' internalizing and externalizing behavior problems through parent-child dysfunctional communication. Another one is that the mothers' differentiation from the family-of-origin influenced children's internalizing behavior problems through daughters' problem-focused coping behaviors as well as parent-child dysfunctional communication.

• 한국사회정책
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• v.24 no.1
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• pp.153-185
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• 2017

The purpose of this study is to investigate the actual conditions and causes of the problem behaviors of Korean Chinese'left-behind'children in China in order to propose a support system to prevent problem behaviors of them. For this purpose, a questionnaire survey was conducted on 399 children who attend at three Korean Chines schools in Yonbian in China. The questionnaire consisted of general characteristics, internalizing problem behavior, social support, self-esteem, and self-resilience. This paper analysed the survey data by employing one-way ANOVA and a structural equation modeling. It verified if there is significant difference in internalizing problem behaviour, self-esteem, self-resilience, and social support between left-behind children's group and non left-behind children's group. It also identified a structural causal relationship and direct or indirect effects among problematic behaviour, self-esteem, self-resilience, and social support. The results of the analysis are as follows. First, there was a statistically significant difference in the social withdrawal and depression of internalizing problem behaviors between left-behind children's group and non left-behind children's group. Second, the left-behind children's group showed no significant difference in self-resilience and social support compared to non left-behind children's group, but showed a significant difference in self-esteem. In the positive self- esteem factor, non left-behind children's group showed much higher score whereas left-behind children's group was higher in the negative self-esteem factor. Third, social support for left-behind children's group has a statistically significant direct negative effect on internalizing problem behaviors, and indirectly negative effects on problem behavior through self-resilience. These results suggest the necessity of establishing a social support system for mitigating and preventing problem behaviors and the necessity of preparing measures to improve self-resilience. Based on the results of the study, we discussed how to establish a social support system in China to mitigate internalizing problem behaviors of Korean Chinese left-behind children.

• Korean Journal of Environmental Agriculture
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• v.35 no.3
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• pp.159-165
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• 2016

BACKGROUND: Carbonized biomass is increasingly used as a tool of soil carbon sequestration. The objective of this study was to evaluate soil carbon storage to application of carbonized biomass derived from pear tree pruning.METHODS AND RESULTS: The carbonized biomass was a mobile pyrolyzer with field scale, which a reactor was operated about 400~500℃ for 5 hours. The treatments were consisted of a control without input of carbonized biomass and two levels of carbonized biomass inputs as 6.06 Mg/ha, C-1 and 12.12 Mg/ha, C-2. It was shown that the soil carbon pools were 49.3 Mg/ha for C-1, 57.8 Mg/ha for C-2 and 40.1 Mg/ha for the control after experimental periods. The contents of accumulated soil carbon pool were significantly (P < 0.001) increased with enhancing the carbonized biomass input amount. The slopes (1.496) of the regression equations are suggested that carbon storage from the soil was increased about 0.1496 Mg/ha with every 100 kg/ha of carbonized biomass input amount.CONCLUSION: Our results suggest that application of carbonized biomass would be increased the soil carbon contents due to a highly stable C-matrix of carbonized biomass. More long-term studies are needed to be proved how long does carbon stay in orchard soils.

• Applied Chemistry for Engineering
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• v.7 no.1
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• pp.67-74
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• 1996

The binary phase equilibrium experiments of carbon dioxide/1,2,3,4 ${\alpha}$-tetrahydro-1-naphthol(${\alpha}$-tetralol) system were conducted to get phase equilibrium and mixture density data at 313.2K, 343.2K and 373.2K and within pressure ranges of 6.0 MPa to 35.0MPa. The phase equilibrium apparatus was type that circulated the vapor and liquid phase, the expended volume measuring system was adopted to microsampling technique for the analysis. The phase equilibrium and mixture density data were obtained for carbon dioxide/${\alpha}$-tetralol system from liquid and vapor phase. The mole fraction of carbon dioxide in liquid phase decreases and the mole fraction of ${\alpha}$-tetralol in vapor phase increases at constant pressure according to increment of temperature, and both the densities of the vapor and liquid phase approach to the mixture critical density as the pressure increases at any temperature. For she thermodynamic analysis, the experimental data were correlated with Peng-Robinson equation in cubic equation of state and compared to theoretical values of carbon dioxide/${\alpha}$-tetralol system. The AAD result was in the range of 1.08%~8.93% in the case of K(1), and was in the range of 45.71%~72.34% in the case of K(2).