• Journal of the Korean Society of Environmental Restoration Technology
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• v.22 no.6
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• pp.77-87
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• 2019

The first grade zones in Ecology and Nature Map are important regions for the conservation of the ecosystem, but it would be degraded by various anthropogenic factors. This study analyzes the relationship between potential land cover change and degradation of the first grade zones using land cover transition probability. As a result, it was shown that most of the first grade zones with degraded were converted from forest to urban(5.1%), cropland(27.2%), barren(11.0%) and grass(27.5%) in Gangwon and forest to urban(18.0%), cropland(15.3%), grass(28.4%), barren(12.3%) in Gyeonggi. The result of the logistic regression analysis showed that the probability of degradation of first grade zone was higher in area where was expected the higher probability of urban, cropland, barren, grass transition. The barren transition probability was the most influential and grass was the next highest. There were regional differences in the probability of urban transition and cropland transition, and the urban transition probability was more influential in Gyeonggi-do. This is because development pressure such as housing site development is high in Gyeonggi-do. Due to the limitations of the Act on Mountain Districts Management, even in the first grade zones, the grade may be degraded. Therefore, if Ecology and Nature Map are used to prevent deforestation or conversion of mountainous districts, it may contribute to the preservation of the ecosystem.

• International Journal of Highway Engineering
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• v.17 no.1
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• pp.105-118
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• 2015

PURPOSES : This study aims to evaluate the road safety of the super-elevation transition section of a left turn curve and suggest the minimum longitudinal grade of a super-elevation transition section to be used before and after a left curved section. METHODS : We evaluated the road condition by means of the safety-criterion-evaluation method involving side friction factors, and then solve the problem by introducing the minimum longitudinal grade criterion based on conditions described in the hydraulics literature. RESULTS : It was calculated that when a road satisfies hydroplaning conditions, the difference between side friction assumed and side friction demanded is less than -0.04. In this case, the safety criterion for the condition is unsatisfied. Conversely, when a road is in a normal state under either wet or dry conditions, it was calculated that the difference between side friction assumed and side friction demanded is more than 0.01. Thus, the safety criterion for this condition is found to be satisfied. After adjusting the minimum longitudinal grade applied to a super-elevation transition section, the hydroplaning condition can be eliminated and the safety criterion can be met for all sections. CONCLUSIONS : It is suggested that a minimum longitudinal grade should be provided on super-elevation transition sections in order to prevent hydroplaning.

• Human Ecology Research
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• v.59 no.2
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• pp.199-213
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• 2021

The purpose of the study was to apply latent transition analysis to the work-family balance of working mothers with a child in elementary school by focusing on the effect of antecedents on both work-family balance typology and the transition between typologies. Data from 400 working mothers who participated in the eighth and eleventh waves of the Panel Study on Korean Children were used. The results can be summarized as follows. First, the latent profile analysis of working mothers whose children were in the first grade classified the work-family balance types as 'contradictory' or 'beneficial' and of working mothers whose children were in the fourth grade as 'conflictual', 'contradictory', 'high beneficial', 'low beneficial' or 'beneficial'. Second, working mothers whose work-family balance was 'contradictory' or 'beneficial' when their children were in the first grade mostly had, respectively, a 'low beneficial' or a 'high beneficial' balance when their children were in the fourth grade. Third, the probability of being classified into each type differed according to subjective happiness and marital conflict in the first grade, and marital conflict and social support in the fourth grade. Moreover, marital conflict and social support were significant in the transition between the types of work-family balance. The study showed that the types of work-family balance differed for each time point for individual working mothers. The study also highlighted the importance of parenting-related personal, family and social factors in determining the work-family balance type and transition between types.

• Human Ecology Research
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• v.60 no.1
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• pp.53-68
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• 2022

Using a person-centered approach, the current study investigated latent profiles for the emotional and behavioral problems of students in sixth-grade in elementary school and second grade of middle school. The aim was to explore latent transition patterns and verify the factors affecting the transitions. The participants were 1,937 adolescents who responded to the 3^rd year (6^th grade of elementary school; Time 1), 4^th year (1^st grade of middle school), and 5^th year (2^nd grade of middle school; Time 2) of the Korean Children Youth Panel Study. Latent profile and latent transition analyses were performed. The results were as follows: first, the latent profile of emotional and behavioral problems changed from Time 1 to Time 2. The latent groups at Time 1 were classified into low, moderate, high, and externalizing-dominant, whereas at Time 2, five groups were identified: low, moderate, high, externalizing-dominant, and withdrawal-dominant. Second, transition analyses revealed that although 22.3-57.0% of latent groups remained unchanged, there were significant changes over time between groups, as a new group ('withdrawal-dominant') emerged in Time 2. Third, different factors influenced the latent profile transition of emotional and behavioral problems depending on the transition pattern. Higher levels of self-esteem, better relationships with peers and teachers, and lower levels of parental inconsistency meant emotional and behavioral problems had not worsened at Time 2. The results suggest that early interventions are needed during the transition from childhood to early adolescence.

• Transactions of Materials Processing
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• v.8 no.3
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• pp.271-271
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• 1999

A concentration change during grade transition operation in thin slab casting is investigated through computer simulation and the results are compared with experimental measurements. Fluid flow and mixing patterns in various tundish levers and flow rates were analysed by a three-dimensional mathematical model. Based on the contained results, a simple, efficient and accurate computational model is suggested to predict the concentration profile at the outlet of the tundish. Based on the model, mixing in and below the mold was analyzed considering electromagnetic braking force. The predicted concentration profiles show good agreements with the measured values. It is found that the lower vortices in the mold are suppressed by the electromagnetic field and a plug-like flow region develops, which decreases the intermixing of two different grades of steel and shortens the length of transition region.

• Journal of the Korean Institute of Gas
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• v.19 no.6
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• pp.62-66
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• 2015

Considering for plants and structure under extreme conditions is required for the successful design, especially temperature and pressure. The ductile-brittle transition temperature (DBTT) for the materials under extreme condition needs to be considered. In this study, A-grade mild steel for the LNG carrier and offshore plant was examined by performing low-temperature Charpy V-notch (CVN) impact tests to investigate DBTT and the fracture toughness. The absorbed energy decreased gradually with the experimental temperature, which showed an upper-shelf energy region, lower shelf energy region, and transition temperature indicating DBTT. In addition, the fracture surface morphologies of the mild steels indicated ductile fractures at the upper-shelf energy level, with wide and large-sized dimples, whereas a brittle fracture surface, where was observed at the lower-shelf energy level, with both large and small cleavage facets. Based on the experimental results, ductile brittle transition temperature was estimated in about $-60^{\circ}C$.

• 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.

• Communications of Mathematical Education
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• v.38 no.2
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• pp.121-144
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• 2024

This study analyzes how the academic achievement of students in Korea changes as they transition from 4th grade of elementary school to 2nd grade of middle school, considering that the 4th graders in the previous TIMSS cycle become 2nd graders in the next cycle. In particular, this study selects and compares the eight main countries in the TIMSS math evaluation (Korea, Singapore, Taiwan, Japan, USA, UK, Australia, and Russia) to analyze the trend of change in academic achievement of Korean students according to school grade transition. The trend of change in academic achievement of students was analyzed not only overall but also by content area (number, geometry and measurement, data representation (data and probability/data and probability), gender, and regional scale. The analysis focused on the average score and the proportion of students by achievement level. The results of the study are as follows. First, there was no significant change in the average score of Korean students' academic achievement as the school grade transitioned, but the achievement gap widened in terms of the proportion by achievement level. Second, there were differences in students' academic achievement by content area according to school grade transition, and the pattern differed depending on the evaluation cycle. Third, there was a significant gap in students' math academic achievement depending on gender and regional scale of school location. This study reveals that the achievement gap among students in our country widens as they transition between school levels. The gap is found to vary in terms of achievement level, math content area, student gender, and school location. To alleviate these disparities, more substantial research and support are proposed in addition to policy implementation by the government or provincial offices of education.

• Journal of The Korean Digital Architecture Interior Association
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• v.2 no.1
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• pp.24-31
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• 2002

The purpose of this study was to analyze the transition on architectural data such as valid indoor length, module, ratio of core, floor height, ceiling height and the type of structured cabling system according to the intelligent building grade through case study of the intelligent office buildings constructed in Korea since 1980. The results of this study were as follows. The average floor height was 3.80m, and it was higher in proportion to the IB grade. The average ceiling height was 2.57m, and it didn't have connection with the IB grade. The module of high frequency in application was $3.0{\times}3.0m$, and it showed 25% in the application frequency. The average valid indoor length was 12.27m. The average ratio of core was 24.49%. The type of high frequency in application for the structured cabling was Access Floor Type, and it showed 31% in the application frequency.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.15 no.2
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• pp.31-40
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• 2012

The Environmental Conservation Value Assessment Map (ECVAM) is a five grade assessment map created with nationally integrated environmental information and environmental values. The map is made through the evaluation of 65 items, including greenbelt area and naturalness. Naturalness means original state of nature, and it is one of the most important evaluation items for conserving nature. The criteria of naturalness includes the Degree of Green Naturality (DGN) made by MOE. Using the data which has been not updated is a problem of accuracy for ECVAM. Therefore, this study would like to improve the criteria of naturalness. To improve the criteria, the study examined the effectiveness of DGN using field survey. The results of analysis the naturalness without DGN, some area changed grade of naturalness have been already damaged or cleared for agriculture and industrial purposes. The grade of naturalness should be included the concept of vegetation transition like DGN. The study suggested a improved method using vegetation type (natural and planted forest), forest age, and the grade of vegetation conservation. The method was reviewed by experts and field survey. After applying the method in South Korea, the grade of naturalness were distributed evenly like GradeI is 38.87%, GradeII is 37.62%, GradeIII is 23.51%, respectively. From the results of field survey, over 4 grade of forest age in natural forest showed similar pattern of structure and composition in original forests. Therefore, the improved criteria explained the naturalness better than existing criteria, and the accuracy of ECVAM has been improved more.