• Geomechanics and Engineering
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• v.17 no.5
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• pp.439-444
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• 2019

It is generally known that high strength soil is indicative of well-graded particle size distribution. However, there are some special cases of firm ground despite poor grade distribution, especially a specific gap-graded soil. Based on these discoveries, this study investigated the development of an additive of gap-graded soils designed to increase soil strength. This theoretical concept was used to calculate the mixed ratio required for optimal soil strength of the ground sample. The gap-graded aggregate was added according to Plato's polyhedral theory and subsequently calculated ratio and soil strength characteristics were then compared to characteristics of the original soil sample through various test results. In addition, the underground stress transfer rate was measured according to the test conditions. The test results showed that the ground settlement and stress limit thickness were reduced with the incorporation of gap-graded soil. Further field tests would confirm the reproducibility and reliability of the technology by using gap-graded soil to reinforce soft ground of a new construction site. Gap-graded soil has the potential to reduce the construction cost and time of construction compared to other reinforcing methods.

• Education of Primary School Mathematics
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• v.15 no.1
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• pp.13-29
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• 2012

This study is the analytic research of items having gender gap in 6th grade students in 'National Assessment of Educational Achievement(NAEA)'. For this problem solving, the following was investigated. First, items having gender gap were selected in NAEA for the past eight years. Then, the mathematical factors that cause gender gap were analyzed. Second, to do this the field test was developed using item concept map. Finally, after the analysis of field test result the reason of gender gap was deduced. Through this study the improvement of mathematics teaching and learning method in elementary school is expected.

• Journal of the Korean School Mathematics Society
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• v.10 no.4
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• pp.415-435
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• 2007

A transition from elementary to secondary school, and among grades, among learning contents is a essential problem in education. A connectivity between learning contents is important in student's growth and development. A gap between lower grades and higher grades in elementary school is no less extensive than a gap between elementary mathematics and secondary mathematics. In this paper, we start with a critical mind about a transition and connectivity between lower grades and higher grades in elementary school. In order to compare between elementary grades, we firstly focus 4th grade mathematics which finish lower grades and start higher grades at the same time. First, we make up a questionnaire to 4th grade students and teachers in charge 4th grade. A questionnaire is composed of questions about the degree of difficulty in the learning(and teaching) of 4th grade mathematics comparing with 3rd grade mathematics. Second, we compare to lower grades lessons(1st grade) and 4th grade lessons using a qualitative method. we analyze the lesson contents, activities and time through 'analysis of the learning course'. And we compare the pattern of eliciting questions, question patterns, nomination patterns and feedback patterns between 1st grade and 4th grade lessons. We hope that this paper is a fundamental sources in investigating a connectivity between lower grades and higher grades in elementary mathematics in the future.

• Nuclear Engineering and Technology
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• v.55 no.5
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• pp.1519-1526
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• 2023

For the first time Aluminium-BariumeZinc oxide nanocomposite (ZABONC) was synthesized by solution combustion method where calcination was carried out at low temperatures (600℃) to study the electromagnetic (EM) (X/γ) radiation shielding properties. Further for characterization purpose standard techniques like PXRD, SEM, UV-VISIBLE, FTIR were used to find phase purity, functional groups, surface morphology, and to do structural analysis and energy band gap determination. The PXRD pattern shows (hkl) planes corresponding to spinel cubic phase of ZnAl₂O4, cubic Ba(NO₃)₂, α and γ phase of Al₂O₃ which clearly confirms the formation of complex nano composite. From SEM histogram mean size of nano particles was calculated and is in the order of 17 nm. Wood and Tauc's relation direct energy band gap calculation gives energy gap of 2.9 eV. In addition, EM (X/γ) shielding properties were measured and compared with the theoretical ones using standard procedures (NaI (Tl) detector and multi channel analyzer MCA). For energy above 356 keV the measured shielding parameters agree well with the theory, while below this value slight deviation is observed, due to the influence of atomic/crystallite size of the ZABONC. Hence synthesized ZABONC can be used as a shielding material in EM (X/γ) radiation shielding.

• Human Ecology Research
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• v.54 no.5
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• pp.475-485
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• 2016

This study explored mothers' and grandmothers' perception regarding child rearing practices as overprotective behaviors for first to third grade levels of elementary school. The study was conducted on 202 mothers and grandmothers of first to third grade elementary school students. Questionnaires were made with 40 questions on overprotection behaviors selected from the existing questions for preschooler, high grade elementary students, and youth. The questionnaires were distributed to target subjects to answer how they would perceive when each of question is applied to their lower grade elementary students. Based on the collected responses and the factor analysis, it was found out that the overprotective behaviors were classified into four factors such as "reduction in independence," "over-sensitiveness to safety," "interference in daily life," and "health anxiety." There were significant differences in the perception of the overprotective behavior by the subjects depending on the generations, features of children and mothers. This study focused on the lower grade elementary school students who have been removed from studies due to the lack of intervention measures. It has the implication in that the findings of the study can give the basic data for the development of the scale on overprotective behaviors in lower grade elementary school students.

• The Journal of Korean Society for School & Community Health Education
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• v.17 no.2
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• pp.1-16
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• 2016

Objectives: The objective of this study is to evaluate the correlates of depression and perception gap of adolescents' Health-Related Quality of Life (HRQOL) between Parents and Children. Methods: Research targets are all students and their parents who are enrolled in from 1st~3rd grade of middle school to $1^{st}$ grade of high school which was selected intentionally. The survey was conducted from May $16^{th}$ to June $9^{th}$ in 2014 by research staffs equipped with structured questionnaire. $PedsQL^{TM}4.0$ Generic Core Scales and Korean form of the Kovacs' Children's Depression Inventory were the main tool for measuring the HRQOL and depression. Data of 985 respondents, both of parents and children, was used for analysis of this study. Results: In terms of gender difference of depression, 5.8% of adolescents, 3.2% of male and 8.5% of female (p<0.001), are shown depression symptom. Depression rate of the low level students of academic achievement was 11.0% which is the lowest rate to compare to 4.3% of middle level and 2.6% of high level students (p<0.001). The case that parents overestimated their children's overall HRQOL is 3.699 times more likely to have depression symptom than the case which is in concurrence between parents and children. Especially the overestimation in social, emotional, and academic area of HRQOL promote depression 3.918 times, 3.371 times, and 2.258 times more than the agreement occurred of each areas. In contrast underestimation in physical area of HRQOL reduce depression 0.266 times less than the agreement occurred of the area. Conclusion: The perception gap of adolescents' HRQOL between parents and children is the most influential factor to adolescents' depression among all variables which was evaluated in this study.

• Korean Journal of Radiology
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• v.2 no.4
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• pp.216-221
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• 2001

Objective: To compare, in terms of their demonstration of tears of the anterior glenoid labrum, oblique axial MR arthrography obtained with the patient's shoulder in the abduction and external rotation (ABER) position, with conventional axial MR arthrography obtained with the patient's arm in the neutral position. Materials and Methods: MR arthrography of the shoulder, including additional oblique axial sequences with the patient in the ABER position, was performed in 30 patients with a clinical history of recurrent anterior shoulder dislocation. The degree of anterior glenoid labral tear or defect was evaluated in both the conventional axial and the ABER position by two radiologists. Decisions were reached by consensus, and a three-point scale was used: grade 1=normal; grade 2=probable tear, diagnosed when subtle increased signal intensity in the labrum was apparent; grade 3=definite tear/defect, when a contrast material-filled gap between the labrum and the glenoid rim or deficient labrum was present. The scores for each imaging sequence were averaged and to compare conventional axial and ABER position scans, Student's t test was performed. Results: In 21 (70%) of 30 patients, the same degree of anterior instability was revealed by both imaging sequences. Eight (27%) had a lower grade in the axial position than in the ABER position, while one (3%) had a higher grade in the axial position. Three whose axial scan was grade 1 showed only equivocal evidence of tearing, but their ABER-position scan, in which a contrast material-filled gap between the labrum and the glenoid rim was present, was grade 3. The average grade was 2.5 (SD=0.73) for axial scans and 2.8 (SD=0.46) for the ABER position. The difference between axial and ABER-position scans was statistically significant (p<0.05). Conclusion: MR arthrography with the patient's shoulder in the ABER position is more efficient than conventional axial scanning in revealing the degree of tear or defect of the anterior glenoid labrum. When equivocal features are seen at conventional axial MR arthrography, oblique axial imaging in the ABER position is helpful.

• Korean Journal of Social Welfare Studies
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• v.47 no.3
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• pp.139-159
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• 2016

This study aims to investigate the wage gap between male and female workers at social welfare institutions and to determine its factors. For this purpose, a Blinder-Oaxaca decomposition and regression models are applied to analyze wage survey data. The results are as follows. Firstly, the gender wage gap of social workers is a bit smaller, compared to the average of wage earners. Secondly, about two-thirds of wage gap is due to differences in productivity(endowment) factors; the other part is due to discrimination. Thirdly, the most important cause of gender wage gap is career disruptions of female workers largely due to marriage and birth. Fourthly, other causes of gender wage gap include differences in education, in job grade, in employment status, and in the characteristics of institutions. Finally, among the discriminating factors worsening gender wage gap, a key factor is a gender discrimination in the compensation for age.

• Education of Primary School Mathematics
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• v.11 no.2
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• pp.95-103
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• 2008

The 7th national mathematics curriculum was revised in 2007. According to the revision curriculum, new texts and guides are developed and will come into effect for elementary and secondary school in 2009. Some contents are shifted and also newly added at the revision curriculum. This paper analyzed the gap between the revision and the 7th national mathematics curriculum based on the shifts in contents, and investigated on the difficulties that some graders probably will undergo owing to shifting the contents between grades. As a result, several important problems were found in some graders between the revision and the 7th national mathematics curriculum. In particular, some graders could not have a chance to learn some mathematical concepts without another lesson plans. For some graders, special lesson plans and supplementations are required. The brief summary of these supplementations as follows: ⅰ) For entering students in 2005, the supplementations about equations and direct proportion and inverse proportion should be needed at the 6th grade in 2010 or at the 7th grade in 2011. ⅱ) For entering students in 2006, the supplementations about estimations and correspondence should be needed at the 4th grade in 2009 or at the 5th grade in 2010. And the supplementations about the relation of fractions and decimals and the ratio should be needed at the 5th grade in 2010. ⅲ) For entering students in 2007, the supplementations about the addition and subtraction of time using second unit and the addition and subtraction of weight should be needed at the 3th grade in 2009 or at the 4th grade in 2010.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2000.10a
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• pp.259-265
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• 2000

This study is a fundamental research for recycling waste vinyl in asphalt concrete mixture for roadway pavement. The mixing method and proper content of waste polyethylene(PE) film were determined through preliminary mix design. This study was performed mix designs using 2 type graduations of aggregate and used two types waste PE film. The asphalt concrete mixture was satisfied with the specification of the Ministry of Construction and Transportation. Its showed that dense grade asphalt concrete mixture containing waste vinyl were higher performance in comparision to other mixtures(common dense grade mixture and gap grade mixtures). From results of this study, it was confirmed that addition of waste vinyl improved on quality of asphalt concrete mixture.