• Journal of the Korean Geotechnical Society
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• v.37 no.12
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• pp.117-125
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• 2021

The occurrence of ground subsidence and sinkhole in downtown areas, which threatens the safety of citizens, has been frequently reported. Among the various mechanisms of a sinkhole, soil erosion through the damaged part of the sewer pipe was found to be the main cause in Seoul. In this study, a random forest model for predicting the occurrence of sinkholes caused by damaged sewer pipes based on sewage pipe information was trained using the information on the sewage pipe and the locations of the sinkhole occurrence case in Seoul. The random forest model showed excellent performance in the prediction of sinkhole occurrence after the optimization of its hyperparameters. In addition, it was confirmed that the sewage pipe length, elevation above sea level, slope, depth of landfill, and the risk of ground subsidence were affected in the order of sewage pipe information used as input variables. The results of this study are expected to be used as basic data for the preparation of a sinkhole susceptibility map and the establishment of an underground cavity exploration plan and a sewage pipe maintenance plan.

• Journal of Elementary Mathematics Education in Korea
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• v.22 no.4
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• pp.517-538
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• 2018

The purpose of this study is to lay the groundwork for effectively supporting mathematics learning for multi-cultural students by enhancing understanding of the cultural background regarding mathematics. In order to attain these purposes, this study compared to learning contents, deployment of contents, teaching method of the Korean and Vietnamese elementary mathematics textbooks. According to analysis, Vietnamese textbooks emphasize mathematical rigor and logic over Korean textbooks, and it integrate learning contents from various areas according to mathematical relevance. But Vietnamese textbooks do not present the connection between mathematical content, such as the combination, symmetry, and coverage of shapes. While Korean textbooks use teaching method that students find and define the concept of shapes themselves, Vietnamese textbooks present concepts of shapes and let students to learn about them. From this result, this study presented suggestions for supporting mathematics learning for multi-cultural students.

• Design Convergence Study
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• v.14 no.2
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• pp.17-32
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• 2015

The perspectives of customers and providers as for the services have the same objective; however, perspectives and objective are distinctly different. But the existing methodologies have mostly pondered only based on the customer-centric perspective or separately from the perspective of providers. It would be necessary to take these two perspectives as a whole by combining them into one perspective since they not only have differences but also common points. Therefore, in this study suggested the System Journey Map in terms of internal staff based on the customer's task in service. System Journey Map is consists of four parts : a customer journey map, thus the performance of internal staff, internal staff satisfaction evaluation, and finally the performance of internal staff assessment of the senior staff. After releasing a service, with customers and internal staff made a point of contact to identify specific behavioral patterns and whether any part of the problem so that this toolkit gives us an expectation to be a useful map, which is the intangible being placed in service, not just visualize and understand for identifying problems.

• Education of Primary School Mathematics
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• v.26 no.3
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• pp.125-140
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• 2023

In elementary school mathematics, the addition and subtraction of fractions are difficult for students to understand but very important concepts. This study aims to examine the teaching methods and visual aids utilized in the context of common denominator fraction addition and subtraction. The analysis focuses on evaluating the lesson flow and the utilization of visual representations in one national textbook and ten certified textbooks aligned with the current 2015 revised curriculum. The results show that each textbook is composed of chapter sequences and topics that reflect the curriculum faithfully, with each textbook considering its own order and content. Additionally, each textbook uses a different variety and number of visual representations, presumably intended to aid in learning the operations of fractions through the consistency or diversity of the visual representations. Identifying the characteristics of each textbook can lead to more effective instruction in fraction operations.

• Korean Journal of Child Education & Care
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• v.17 no.4
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• pp.1-30
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• 2017

The purpose of this study is to investigate the awareness of daycare teachers by the nursery school operation performance of the National Competency Standards(NCS). For this purpose, 35 public and private daycare center, home daycare centers and corporation daycare center teachers were randomly sampled in Busan Metropolitan City. We conducted a questionnaire consisting of 230 sub-elements based on 45 sub-competency unit elements extracted from 12 areas of job ability of the national competence standards. Final questionnaires were collected from 117 questionnaires of 28 national daycare teachers, 30 private daycare teachers, 30 home daycare teachers, and 29 corporation daycare teachers. As a result, there was a difference in the awareness of importance among the four groups in all 12 performance capability units. For the 12 job performance units, the importance was recognized in the order of corporate daycare center, national daycare center, home daycare center, and private daycare center. Among them, "Establishment of Child Care Center Management Policy", "Construction of Child Care Service", "Child Care Activity Management", "Infant and Child Playing Guide", "Body and Art Activity Guidance", "Language, Nutritional guidance" there were no differences in the awareness of the importance of corporate daycare teachers and national daycare teachers, and there was no difference between national daycare teachers and home daycare teachers. However, there was a difference between corporate daycare teachers and home daycare teachers.. There is also a difference in the awareness of importance between home daycare teachers and private daycare teachers. In the remaining five job competence units, "Child Care Assessment", "Support for Infant and Toddler Development", "Cooperation with the Home and Community", "Child Care Management", and "Child Care Research", corporation daycare centers, national daycare centers. There was no statistically significant difference in the awareness of importance, but there was a significant difference from the private daycare teachers. Also this tendency was consistently observed in 45 sub-capacity unit elements.

• Journal of The Korean Association For Science Education
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• v.34 no.8
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• pp.779-786
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• 2014

Elementary children, hoping for jobs in science/engineering(Sci/Eng) or medicine(Med), were surveyed on the reasons for jobs, science/math preferences, interests in science, and science aspirations. For 3rd grade boys, twice more students picked Sci/Eng than Med choices. However, for 6th grade boys, the numbers of Sci/Eng and Med became close. The ratios of girls with Sci/Eng in 3rd and 6th grade did not differ much. The 6th graders chosing Med was 1.4 times bigger than 3rd graders for both boys and girls. For students with Sci/Eng, the most important reason for a job was that he/she liked it. For Med, helping others was as much important as doing what he/she liked. Science preference were the highest in the Sci/Eng group. The Med group came next with the non-science group being last. Math preferences were lower than the science preferences. Therefore, children need to be guided to increase the preferences for math as well as for science to keep the Sci/Eng and Med career choices. The interests in science and the science aspirations show similar patterns. The 3rd graders showed higher value than the 6th graders, the boys higher than girls, and the Sci/Eng group highest, the Med the second and non-science group the last. Science aspirations were higher than the interests only for the Sci/Eng group, while it was lower than the interests in all other groups. This implies that science aspirations might have bigger influence on getting a career in Sci/Eng than interest does.

• Korean Journal of Culture and Social Issue
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• v.10 no.2
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• pp.103-137
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• 2004

This study examines the basis of trust in relationships by adolescents and their parents using the indigenous psychological approach. Using the indigenous methodology, adolescents were asked the reasons why they trusted their mother, father, friends, and teachers. Parents were asked why they trusted their children, spouse and their children's teachers. A total of 1,737 participants completed an open-ended survey: 579 adolescents (274 middle school and 305 high school students) and their parents (579 fathers) and (579 mothers). The results indicate that adolescents trust their parents because of their sacrifice, followed by consanguinity (i.e., blood relationship), respect, their trust in me, dependability, and their advice and counseling. The reasons why adolescents trust their teachers is because of the academic guidance they provide, unconditional trust of teachers, their concern and care, respect for teachers, advice and counseling they provide, they are like parents, and because of their sacrifice for the students. The reasons for trusting their friends are as follows: Dependability, closeness, unconditional trust of friends, their understanding of me, and their emotional support. The reasons why parents trust their children are: Children's sincerity, honesty, consanguinity, parents' expectation and communication with the children, children's obedience, and since they are diligent in their schoolwork. The reasons for trusting one's spouse are reported to be sincerity, their sacrifice for the family, honesty, unconditional trust of a spouse, and because of mutual support. The reasons why parents trust their children's teachers are reported as follows: Unconditional trust of teachers, their sacrifice for the students, and their sincerity. There were no significant differences across the type of school and academic grades in terms of trust of parents. However, middle school students are more likely to trust their teachers, and high school students are more likely trust their friends. The male students rather than female students and those students with higher academic grades are more likely to trust their parents, friends, and teachers. For parents, there were no significant differences across age, sex, and educational status concerning the trust of their children, spouse, and children's teachers. There was a positive correlations between parents' trust of their spouse and children and their children's trust of their parents. There was also a positive correlations of mothers' trust of children's teachers and the children's trust of their teachers.

• Journal of the Korean earth science society
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• v.32 no.7
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• pp.902-912
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• 2011

The purpose of this study was to investigate the effects of teaching based on analysis of a hierarchy of the concepts associated with astronomical observation as well as each learner's status of knowledge through analytical methods of the knowledge state. A test instrument was developed to measure high school students' concepts associated with astronomical observation before instruction. The learners' psychological hierarchy associated with astronomical observation that the participants possessed showed the order of 'motion of the earth${\rightarrow}$coordinate system${\rightarrow}$astronomical observation (mechanism of the telescope${\rightarrow}$installation of the telescope${\rightarrow}$observation through the telescope)', and so was the hierarchy of teaching (70.6%). The learners' knowledge state that is supposed to be similar each other in the ability of observing celestial bodies was different even through they scored the same on the concept test. There were cases with the knowledge state well-structured and not well-structured, which suggests that differentiated instruction with appropriate teaching-learning prescriptions be prepared. An analysis of the knowledge state can play the role of both preparing individualized learning prescriptions and formative evaluation. In the unit dealing with astronomical observation of Earth ScienceI, teaching according to the psychological hierarchy of learners rather than the order in which the textbook syllabi were presented scored significantly higher (p<0.05) on the level of concept achievements. This result suggests that the teacher can help students achieve more efficient in learning by analyzing the learner's knowledge state and reordering the syllabi of the textbook in teaching the concepts associated with astronomical observation.

• Korean Journal of Applied Biomechanics
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• v.18 no.2
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• pp.125-139
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• 2008

The purpose of this study is to compare and analyze a kinematic characteristics of throwing performance among born visually impaired, postnatal visually impaired and visually correct people through their kinematic characteristics. Another purpose of this study is to prevent injury and improve blind's exercise leadership and physical abilities. Three video cameras were used and each camera's shooting velocity was 60field/sec. Then the longest thrown pose was collected and analyzed by using Kwon 3D ver. 3.1 program. The results obtained from this study were followings; 1. During release, the fastest speed of ball was visually corrected followed by postnatal visually impaired and then born visually impaired. 2. Visually corrected used wrist joint well and had wide body round range with similar motion patterns, however born visually impaired couldn't do this at all. 3. Visually corrected used waist to lead shoulder at Phase 2 while throwing ball, but some of born visually impaired and postnatal visually impaired couldn't use waist to lead shoulder. 4. Visually corrected looked at the way where ball would go, but blinds couldn't look where ball would go. 5. Not like visually corrected who show similar patterns, born visually impaired showed each different patterns and some postnatal visually impaired showed similar patterns with visually corrected. 6. While throwing ball, visually corrected showed flexible weight-movement, postnatal visually impaired were not good as visually corrected, and born visually impaired couldn't do weight-movement at all. Synthetically, this result showed that throwing motions are affected a lot by the time when people became blind.

• Journal of Science Education
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• v.35 no.2
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• pp.230-239
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• 2011

This study developed examination test tools for concepts of weather changes of middle school students, analyzed the hierarchy of concepts associated with weather changes by means of knowledge state analysis method, and examined the knowledge state and lesson effects of each individual learner. The hierarchy of the knowledge state of concepts of middle school students associated with weather changes followed the steps of 'humidity ${\rightarrow}$ air mass ${\rightarrow}$ cloud ${\rightarrow}$ precipitation ${\rightarrow}$ front ${\rightarrow}$ weather'. Cases were identified where the knowledge state of students that was thought to be similar to each other among the group of students who have scored almost the same points and thus were thought to have almost the same learning ability, have turned out different in the knowledge state from each other. Namely, the level of knowledge state structuralized differed, suggesting that differing prescriptions should be made according to the knowledge state of each student concerned. Analysis of the knowledge state of learners helps prepare learning prescriptions for each student and appraise prior learning. To examine effects of teaching-learning that has taken into consideration the hierarchy of knowledge state and concepts, lessons were conducted in comparison with the order in which syllabuses are presented in the textbooks, with the result that when knowledge state of learners have been taken into consideration, students made scores significantly higher (p < .05) than otherwise. This indicates that in introducing the unit of weather changes better teaching and learning can be achieved by reordering the contents of subject matters of the textbook by grasping the knowledge state of learners.