• Journal of Korean Elementary Science Education
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• v.33 no.4
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• pp.736-750
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• 2014

The purposes of this study were to investigate concepts of Korean and American elementary school pre-service teachers on combustion, and to compare the concepts of Korean pre-service teachers with those of American pre-service teachers. For this study, concept test on combustion was administered to 23 Korean and 18 American elementary school pre-service teachers. The test composed of 6 items: 'Definition of combustion', 'The reason why a candle in a glass bottle is blown out when the bottle was closed', 'The change of gases in the bottle when a candle burns in it', 'The combustion products of a candle', 'The combustion products of steel wool', and 'The combustion products of a substance'. The results showed that the rates of elementary school pre-service teachers who had scientific concepts on combustion were very low in both Korean and American pre-service teachers' groups, although they were a little different from items. However the rates of pre-service teachers who had partial concepts and misconceptions on combustion were high in two groups. The levels of Korean elementary school pre-service teachers' concepts were a little higher than those of American elementary school pre-service teachers' concepts. The contents and activities on combustion which are in Korean and American science textbooks seem to affect building up their concepts on combustion.

• Journal of the Korean Society of Earth Science Education
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• v.8 no.3
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• pp.378-386
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• 2015

This study is to find out that pre-service elementary teacher's the effects of a ecology mentor club activities to the environmental sensitivity and the effects on the environment friendly attitude of elementary school students. This study has been aimed at 25 students of 5th grade in B metropolitan city S elementary school in 2015, B educational University of elementary pre-service teachers 10 people, Elementary School Teachers10 people to apply a ecology club mentor activities to investigate a comment participated in environmental mentor club activities of elementary pre-service teachers and the environmental sensitivity and the effects on the environment friendly attitude of elementary school students. Procedures for this research was the topic for setting ecology club mentor activities of elementary school students, pre-service elementary school teachers receive consultation from field teachers and guide to ecology club mentor activities of elementary school students. Before the ecology club mentor activities, pre-test environmental sensitivity and the environment-friendly attitude of were carried out. After the experiment, post-test of environmental sensitivity and environmental friendly attitude check was carried out. Also, investigate a comment of pre-service elementary teachers participate and guide to ecology club mentor activities of elementary school students. After the experiment results are as follows. First, the ecology club mentor activities of pre-service elementary school teachers are effective to cultivate environmental sensitivity of the elementary school students. Second, the ecology club mentor activities of pre-service elementary school teachers are effective to cultivate eco-friendly attitude of the elementary school students. Third, after ecology club mentor activities of elementary school students, pre-service elementary school teachers now have a very good feeling. Based on these results, suggestions for further research are as follows. First, the variety of ecological club programs target to elementary school students are needed. Second, there is a need for continuing research on the ecology club activities.

• Journal of Korean Elementary Science Education
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• v.30 no.2
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• pp.255-270
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• 2011

The purpose of this study is to investigate the elementary pre-service teachers' views about "the purpose of science experiments". For the study, the views about the purposes of scientists' experiments and school science experiments were surveyed from 227 pre-service teachers. And the responses were analyzed based on their gender, intensive majors and school science test scores. The main results of the study are as follows. First, in relation to the purpose of scientists' experiments, the pre-service teachers considered internal values of doing experiments were more worthy than the external values of it. In particular, the pre-service teachers responded that the most important purpose of the science experiments is 'to get the evidences for the theories and arguments'. On the other hand, the views from the women and social studies major pre-service teachers were more diverse than those of the man and science major pre-service teachers. Second, in relation to the purpose of school science experiments, the pre-service teachers excessively considered that the internal values of school science experiments were more worthy than the external values. In particular, only few pre-service teachers were aware of social and personal aspects of the experiments, though they considered well that the experiments are useful tools for the school science study. Third, there were quite different aspects of pre-service teachers' views between the purposes of scientists' experiments and school science experiments. For example, the views about the scientist's experiments were relatively broad concerning the nature of scientific experiments, but the school science experiments were just regarded as an educational tool for the science study. Based on the results from the study, some science educational implication were discussed.

• Phonetics and Speech Sciences
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• v.3 no.1
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• pp.117-123
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• 2011

Most individuals with hearing impairment have difficulty in understanding speech in noisy situations. This study was conducted to investigate sentence recognition ability using the Korean Standard-Sentence Lists for Preschoolers (KS-SL-P2) in pre-school age children with cochlear implants and hearing aids. The subjects of this study were 10 pre-school age children with hearing aids, 12 pre-school age children with cochlear implants, and 10 pre-school age children with normal hearing. Three kinds of signal-to-noise (SNR) conditions (+10 dB, +5 dB, 0 dB) were applied. The results for all pre-school age children with cochlear implants and hearing aids presented a significant increase in the score for sentence recognition as SNR increased. The sentence recognition score in speech noise were obtained with the SNR +10 dB. Significant differences existed between groups in terms of their sentence recognition ability, with the cochlear implant group performing better than the hearing aid group. These findings suggest the presence of a sentence recognition test using speech noise is useful for evaluating pre-school age children's listening skill.

• Structural Engineering and Mechanics
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• v.57 no.3
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• pp.389-402
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• 2016

Based on the traditional mechanical model of thin-walled straight beam, the paper makes analysis and research on the pre-twisted thin-walled beam finite element numerical model. Firstly, based on the geometric deformation differential relationship, the Saint-Venant warping strain of pre-twisted thin-walled beam is deduced. According to the traditional thin-walled straight beam finite element mechanical model, the finite element stiffness matrix considering the Saint-Venant warping deformations is established. At the same time, the paper establishes the element stiffness matrix of the pre-twisted thin-walled beam based on the classic Vlasov Theory. Finally, by calculating the pre-twisted beam with elliptical section and I cross section and contrasting three-dimensional solid finite element using ANSYS, the comparison analysis results show that pre-twisted thin-walled beam element stiffness matrix has good accuracy.

• Structural Engineering and Mechanics
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• v.59 no.2
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• pp.327-341
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• 2016

This study addresses the effect of pre-stressed cables on a pre-stressed mega-braced steel frame through employing static analysis and pushover analysis. The performances of a pre-stressed mega-braced steel frame and a pure steel frame without mega-braces are compared in terms of base shear, ductility, and failure mode. The influence of the cable parameters is also analyzed. Numerical results show that cable braces can effectively improve the lateral stiffness of a pure frame. However, it reduces structural ductility and degenerates structural pre-failure lateral stiffness greatly. Furthermore, it is found that 20% fluctuation in the cable pretension has little effect on structural ultimate bearing capacity and lateral stiffness. As comparison, 20% fluctuation in the cable diameter has much greater impact.

• Journal of Korean Home Economics Education Association
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• v.7 no.2
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• pp.35-50
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• 1995

The purpose of this study was to investigate the recognition degrees of contents in Home Economics textbook for middle school students among pre-middle school students and their parents. It is for developing better Home Economics textbook. Three objectives of this study were ; 1) To find the recognition degrees of the fact that Home Economics subject is supposed to utilize for not only girls, but boys students in middle schools in 1996 among pre-middle school students and their parents. 2) To find the degrees of necessity in each field of Home Economics subject among pre-middle school students and their parents. 3) To find the differences in recognition degrees of understandings, attitudes, and sills of Home Economics subject between pre-middle school students and their parents. Questionnaire survey method was utilized to 1,205 sixth grade students and their parents in Pusan. The results of this study as follows; 1) It was low that the recognition degrees of the fact that Home Economics subject is supposed to utilize for both girls and boys in middle school among both pre-middle school students and their parents. This result implies that it is important to important to disseminate the curriculum change in Home Economics practice to the public. 2) It was high that the recognition degree of necessity in each field of Home Economics subject among pre-middle school students and their parents. The recognition degree were different according to sociodemographic factors. That is , $\circled1$the recognition degrees of students were lower than their parents; $\circled2$ the recognition degrees of parents who have high education were higher than those who have low education ; $\circled3$ the recognition degree of an environmental field was highest. 3) There were little differences between pre-middle school students and their parents in the recognition degrees of understandings, attitudes, and skills of Home Economics subjects: The recognition degrees of girls fathers showed higher scores than boys fathers those of in understandings and skills of Home Economics subject. The recognition degrees of girls fathers showed higher scores than those of girls in attitudes of Home Economics subject.

• Korean journal of food and cookery science
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• v.22 no.5 s.95
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• pp.553-564
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• 2006

This study was conducted to investigate the use and acceptability of pre-processed food materials in school foodservice. Self-administered questionnaires were collected from 81 schools in the Kyunggi area. Statistical data analysis was completed using the SPSS v. 10.0 program. Eighty-one school dietitians from 31 elementary, 31 middle, 19 high school participated in the survey. Most of the subjects (over 95%) understood that it is necessary to use pre-processed foods, and they considered food hygiene as the most important factor. The percentages of school foodservices that purchased and used pre-processed foods were: 82.7% for cabbage, 86.4% for onion 72.8% for carrot, 97% for garlic, 82.7% for potato, and over 90% for meats and fishes. Dietitians were most satisfied with the performance of ‘trash reduction’, and ‘saving cooking time’ when using pre-processed food materials. ‘Appearance’, ‘freshness’, ‘hygiene’, ‘nutrition’, and ‘specialty of the food-processing company’ were aspects of the most concern when purchasing and using pre-processed food materials.

• Journal of The Korean Association For Science Education
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• v.35 no.3
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• pp.363-374
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• 2015

The purpose of this study is to investigate the learning contents presented in high school science and in pre-service science textbooks of college of education, and to examine educational implications for pre-service science teachers by analysing their connection to each other. High school science is called as 'convergence science.' Seven high school science textbooks and eleven science textbooks related to physics, chemistry, biological science, and earth science for pre-service teachers were selected to analyse learning contents. The relationship between high school science with those of college-level science textbooks for pre-service science teachers was found when the learning contents were compared. Science textbooks for pre-service science teachers have the biggest number of learning contents on the chapter 'Energy and Environment' of high school science. About 86.6% of learning contents of high school science were introduced on textbooks on science, but pre-service teachers should learn the remainder. The part of learning contents presented in high school science textbooks was higher than the college-level for pre-service science teachers. Moreover, the part of learning contents was included in Engineering & Technology. And these required a special teacher education. Accordingly, the results suggested that learning contents for high school science should be optimized and reduced. Also, various educational programs should be developed and educational curriculum for pre-service science teachers should be revised.

• Geomechanics and Engineering
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• v.32 no.3
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• pp.321-333
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• 2023

Rock masses often contain natural fractures of varying sizes, and the size of the natural fractures may affect the propagation of hydraulic fractures. We conduct a series of triaxial hydraulic fracturing tests to investigate the effect of the pre-existing fracture size a on hydraulic fracture propagation. Experimental results show that the pre-existing fracture size impacts hydraulic fracture propagation. As the pre-existing fracture size increases, the hydraulic fracture propagates towards the pre-existing fracture tips, evidenced by the decreased distance between the final hydraulic fracture and the pre-existing fracture tips. Furthermore, the attracting effect of pre-existing fracture tips increases when the distance between the wellbore and the pre-existing fracture is short (L/D=2 or 4 in this study). With increased distance between the wellbore and the pre-existing fracture (L/D=6 in this study), the hydraulic fracture propagates to the middle of the pre-existing fracture rather than the tips, as the attracting effect of the pre-existing fracture diminishes.