• Korean Journal of Veterinary Research
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• v.49 no.4
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• pp.279-284
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• 2009

This research aimed to investigate the time-course effect of epichlorohydrin (ECH) on epididymal histopathology in Sprague-Dawley rats. Twenty-four male rats were randomly assigned to four groups with 6 rats in each group and were administered a single oral dose of ECH (70 mg/kg) or its vehicle. Six animals each were sacrificed on days 0 (control), 1, 2, and 7 after treatment. During the study period, clinical signs, body weights, reproductive organ weights, testicular spermatid count, epididymal sperm count, motility and morphology, and histopathology were examined. No treatmentrelated effects on body weights and reproductive organ weights were noted at any time point. On the contrary, sperm motility decreased slightly on days 1 and 2 after treatment and then decreased significantly on day 7 after treatment. The first signs of histological changes were the appearance of cell debris in the ducts and vacuolization of the epithelial cells observed in the proximal caput epididymis on day 1 after treatment. The incidences and grades of the histological changes including cell debris in the ducts, epithelial vacuolization, oligospermia, and epithelial disruption increased on day 2 and then decreased slightly on day 7 after treatment. These results show that a single oral dose of 70 mg/kg ECH to male rats results in cell debris in the ducts and vacuolization of the epithelial cells in the proximal caput epididymis, followed by reversible oligospermia, epithelial disruption, and decreased sperm motility.

• Hwankyungkyoyuk
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• v.18 no.1 s.26
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• pp.1-30
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• 2005

Environmental education as worldwide sustainable education is effective when it is carried out as early as possible. But we do not have any aims and textbooks for environmental education in the elementary school. The purpose of this study is systematizing environmental syllabus as sustainable education. To achieve this purpose, firstly, the meaning of environmental education as sustainable education was conceptualized, secondly, the aims of environmental education was set up, thirdly, domains of environmental education was revised, and lastly, the syllabus for environmental instruction were created for each grade. Literature review was practiced over 143 textbooks and teacher's guidebooks from the 4th to 7th curriculum period. The result of this study follows. First, environmental education as sustainable education in the elementary school was conceptualized as an integrative education to keep the lifelong education and welfare. Second, the synthetic aim of environmental education as sustainable education in the elementary school was set up as 'cultivating desirable environmental people that behave for the sustainable future with environment-friendly value and attitude. Third, our environmental domains were divided into 11-12 independent areas, and ESSD (Environmentally Sound and Sustainable Development) was located on the subcategory of environmental domain. These domains were revised into three environmental domains and five sub-domains. Fourth, according to the aims of environmental education as sustainable education and five environmental domains, 253 objectives were established. Fifth, objectives of environmental education of 10 subject matters and integrative objectives were presented. Sixth, based on the objectives of domains and subject matters, 255 contents for environmental education in the elementary school were abstracted and distributed to each grade in the consideration of balance among domains and appropriateness of grades. Seventh, analytic results of textbooks of 7th curriculum shows heavy stress on the 'knowledge perception' section and deficiency on the altitudes and behavior section. The environment-related level and contents overlapped and fragmented deeply. Furthermore, 33 parts of textbooks could bring to mis-concept on environment.

• Journal of Practical Engineering Education
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• v.10 no.1
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• pp.25-33
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• 2018

As the IT industry develops, The field of e-learning based on existing theoretical subjects has expanded to fields requiring actual education. Courses that require practical training in e-learning must be evaluated to have learning outcomes through on-line practice. In this research, a student at Cyber University mechatronics engineering studies 'PLC Control' and 'Servo Motor Control', which are subjects of the undergraduate major, through 'Prime College's CyberLAB' for learning by e-learning investigated whether there was a learning result. For this reason, CyberLAB was conducted. And for the students who took the course for two years, We confirmed through the 5 - point scale questionnaire and grades that the practical subjects had a significant effect on e - learning.

• Journal of The Korean Association of Information Education
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• v.26 no.2
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• pp.85-95
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• 2022

This paper sought to find significant learning behavioral indicators and their correlation with the academic achievements of elementary teacher candidates engaged in an online course using MS Teams during the COVID-19 pandemic. Focused on variables such as the number of visiting days to MS Teams, on-time online assignments, conversation activities, posts, and replies, MS Insights data in the LMS environment were collected in the fall term of the 2020 academic year and analyzed in Pearson correlation and multiple regression. The number of visiting days and on-time online assignments were significantly correlated with their grades, whereas the indicators including average weekly conversation activity, posts, and replies did not have a significant effect on the achievements. Furthermore, the results revealed that the subject's behavioral intention to submit on-time assignments significantly predicted learner achievements.

• Communications of Mathematical Education
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• v.19 no.4 s.24
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• pp.633-647
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• 2005

The rapid change in school mathematics curricula occurred over last some periods requires lots of change or improvement in the education method for the university mathematics, especially in calculus. As an effort in this direction we restrict our concern to the freshmen of year 2002 of the Korea university of technology and education to investigate a correlation between their mathematics score on the national entrance examination and achievement score measured by their final grades in a calculus course. As a result of this research we propose a step-wise level educational model for the calculus education. In the model an appropriate teaching contents and method proceeding through the three steps are suggested and implementation issues are discussed. We believe that carrying out mathematics curricular are suggested in the model will be of service to calculus education particularly for student under the 7th national curriculum reform.

• The Mathematical Education
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• v.48 no.1
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• pp.61-80
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• 2009

The purpose of this study was to develop case-based pedagogy in mathematics for elementary school teachers and to investigate how they participate in the course employing case-based pedagogy. The 13 cases were developed and employed in pre-service teacher education. As such, the cases covered all content areas across grades, and included detailed description of mathematics instruction, questions for discussion, theoretical review related to each case, focus analysis and additional analysis, etc. This paper describes in what ways the participant teachers discussed cases, how case-based pedagogy had an influence on the teachers' own instruction during the practicum period, and how they assessed case-based pedagogy. This paper provides issues and suggestions for the professional development of mathematics teachers on the basis of empirical background.

• Journal of Korean Elementary Science Education
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• v.29 no.2
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• pp.166-185
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• 2010

Astronomy areas in the elementary science textbooks of Korea and the U.S.A. have been compared to find advantages and disadvantages of Korean textbooks. The analysis objects are the 7th national curriculum science textbooks for Korea and the Macmillan McGraw-Hill(MMH) science textbooks for the U.S.A. The results are as follows: First, in contexts, Korean science textbooks contain mostly inquiry activities and partly reading materials. However, MMH ones contain mostly explanations including photographs, related activities, and various reading materials. Second, in the contents and order, the observation activities of constellations are emphasized in Korean science textbooks, while the MMH ones explain solar system up to the universe in details. In addition, Korean science textbooks deal with one subject only once during the whole elementary course while MMH ones deal with one subject repeatedly in several grades. Third, in the frameworks of the international mathematics and science study (TIMSS) 2007, Korean science textbooks do not introduce some contents presented in TIMSS 2007, whereas MMH textbooks introduce every one of them in time. Fourth, the major subjects such as change of moon phases, constellations, the solar system, and change of seasons are handled independently in Korean science textbooks without strong correlation, while they are systematically done related with the rotation and the revolution of the earth in MMH ones.

• The Journal of Korean Academic Society of Nursing Education
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• v.23 no.4
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• pp.474-485
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• 2017

Purpose: The purpose of this study was to identify a causal relationship among major satisfaction, career decision autonomy, and career search behavior of nursing college students in clinical practice experience. Methods: Data were collected using a self-reported questionnaires from 197 nursing students in S city from December 1 to 23, 2016. These were then analyzed by descriptive statistics, ANOVA, t-test, Pearson correlation coefficient, and multiple regression using SPSS/PC+ program. Results: The results suggest that major satisfaction was correlated with career decision autonomy; likewise, major satisfaction was correlated with career search behavior. The factors influencing career search behavior were grades and major satisfaction. Conclusion: It is necessary to develop a learning method considering interest and aptitude to increase the satisfaction of the major and to apply the various programs to understand the self and the work environment so as to determine how desirable the course will be.

• Journal of Engineering Education Research
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• v.14 no.5
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• pp.3-9
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• 2011

This study analyzes results of current Basic Design Engineering teaching and learning methods and makes suggestions based on its findings. To reach these conclusions, participants were 112 second-year students in Basic Design Engineering courses. In the results of t-test, there were significant statistics in learners' satisfaction, achievement of course outcomes and grades. Also the average of factors of the problem based learning strategy is higher than those of the project based strategy. Based on this study's findings, recommendations for effective teaching and learning strategies are made for Basic Design Engineering courses.

• Magazine of the Korean Society of Agricultural Engineers
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• v.15 no.1
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• pp.2904-2912
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• 1973

The density of soil is one of the most important of its engineering properties, and many soil-engineering operations directed toward improving the density characteristics of matecal. This report is a study on relationship between density, permiabilty and other physical properties of compacted soil in various desity grades. The results of the study can be summariged as follow: 1. The optimum moisture content of soil increses with increasing of fine particles and a relationship between both parameter is $w_0=0.1765.n$ Where, n is passing percentage from #200 sieve. 2. The porosity of soil increases with increasing of optimum water content as $e=aw_0+b$ without having relation to compaction ratio. 3. The increment of permeability of soil is high when the compaction ratio is increased and the phenomenon is conspicuous in case of course soil and non-plastic soil. 4. The permeability of soil decreases with increasing of optrimum water content and the phenomenon is conspicuous when compaction ratio decreases. And the permeability is almost constant when optimum water content is more than 25 percent, even though compaction ratio changes. 5. The permeablity of soil increanses when the amount of fine particles is very few, the permeability is almost constant as being impervious condition without having relation to compaction ratio when there in more than 90 percent of fine particles(less than #200 sieve).