• Journal of Korean Neurosurgical Society
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• v.60 no.6
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• pp.691-700
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• 2017

Objective : The authors prospectively analyzed the effect of one-level or two-level anterior cervical discectomy and fusion (ACDF), comparing stand-alone cages and cage-with-plate fixation constructs with respect to clinical outcomes and radiologic changes. Methods : A total of 84 patients who underwent one-level (n=52) or two-level ACDF (n=32) for cervical disc disease and who completed 2 years of follow-up were included in this study. The patients were divided by cervical level and grouped into ACDF-Cage-only and ACDF-Cage-with-plate groups. The following parameters were assessed using radiographs : subsidence, C2-C7 lordosis angle, fusion segment angle, adjacent disc space narrowing, and fusion status. Clinical outcomes were assessed using the neck disability index (NDI) and visual analog scale scores for arm pain. Results : In the comparison of one-level ACDF-cage-only and ACDF-cage-with-plate groups, the NDI score was better in the cage-only group at the 3-, 12-, and 24-month follow-ups : however, no significant difference in clinical outcomes was observed. In the comparison of two-level ACDF-cage-only and ACDF-cage-with-plate groups, no difference in any clinical outcome was observed between the two groups. At the 24-month follow-up, subsidence was observed in 45.8% of patients in the one-level cage-only group and 32.1% of patients in the one-level cage-with-plate fixation group. There was no statistically significant difference in the incidence rate between the two groups (p=0.312). Subsidence in the two-level cage-only group (66.6%) was significantly more frequent than in the two-level cage-with-plate fixation group (30%; p=0.049). The fusion rate for patients in the one-level cage-only group was not significantly different from that in the one-level cage-with-plate fixation group (cage-only, 87.5%; cage-with-plate fixation, 92.9%; p=0.425) ; fusion rate in the two-level patients were also similar between groups (cage-only, 83.3%; cage-with-plate fixation, 95%; p=0.31). Conclusion : Our clinical results showed that for single-level cases, plate fixation had no additional benefit versus cage-only; for two-level ACDF cases, the fusion rate and clinical outcomes were similar, although the cage-with-plate fixation group had a lower incidence of cage subsidence than did the cage-only group. We conclude that physicians should be aware of this possible disadvantage associated with using cervical plates in one-level ACDF. However, in two-level ACDF, subsidence is more likely to occur without plate fixation, and thus the addition of plate fixation should be considered.

• Structural Engineering and Mechanics
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• v.64 no.1
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• pp.93-107
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• 2017

The article presents the vibration and acoustic responses of un-baffled doubly curved laminated composite panel structure under the excitation of a harmonic point load. The structural responses are obtained using a simulation model via ANSYS including the effect various geometries (cylindrical, elliptical, spherical and hyperboloid). Initially, the model has been established by solving adequate number of available examples to show the convergence and comparison behaviour of the natural frequencies. Further, the acoustic responses are obtained using an indirect boundary element approach for the coupled fluid-structure analysis in LMS Virtual.lab by importing the natural frequency values. Subsequently, the values for the sound power level are computed using the present numerical model and compared with that of the available published results and in-house experimentally obtained data. Further, the acoustic responses (mean-square velocity, radiation efficiency and sound power level) of the doubly curved layered structures are evaluated using the current simulation model via several numerical experimentations for different structural parameters and corresponding discussions are provided in detail.

• Journal of Educational Research in Mathematics
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• v.10 no.1
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• pp.35-55
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• 2000

There seems to be a public consensus that the content of Korean mathematics textbooks is extensive and of a high level of difficulty. However, such judgment is the result of a generalization based on individual experience or on the results from comparisons of the international levels of achievement. Therefore, a more objective and stricter approach to the determination of the quantity and level of difficulty of mathematics content is necessary. For this purpose, this study has compared the content of Koreas 6th and 7th junior high school curriculums, and the Korean mathematics curriculum to textbooks of the United States, which has a considerable influence on the making of Korean mathematics textbooks. First of all, a comparison of Koreas 6th and 7th junior high school mathematics curriculums showed a slight reduction in the total quantity of content, as more content was deleted than was added in the 7th curriculum. However, given the fact that the number of hours of mathematics classes has been reduced, the reduction in content cannot be regarded as anything more than a simple reflection of the reduction in hours, proving that the 7th curriculum has not met its revision objective of reducing the content by 30%. Meanwhile, the comparison of the United States junior high school mathematics textbooks to Korea's 7th curriculum showed that the 7th grade content in the United States was much broader, encompassing content which in Korea ranged from the 2nd grade of elementary school to the 2nd year of junior high school. Therefore, on the surface, it may appear that the overall level of content in the American mathematics textbook is lower than that of the Korean. However, there are several cafes, such as statistics and probability, where certain content was more difficult and introduced at an earlier grade in the United States than in Korea. In fact, it can be said that Korea students tend to find content of the mathematics textbooks to be harder than they actually are because they are delivered as a mere aggregate of algorithms, with little consideration to its application in their everyday lives. In this respect, there is much room for improvement on the mathematics textbooks of Korea.

• Journal of The Korean Association For Science Education
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• v.27 no.3
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• pp.180-189
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• 2007

This study investigated the influences of reciprocal peer tutoring (RPT) strategy on middle school students' science achievement, self-efficacy, perception of instruction by grouping method and science achievement level. Eighth graders from a middle school in Seoul were assigned to comparison, homogeneous RPT, and heterogeneous RPT groups. The students were taught about 'separation of mixtures' for 8 class hours. After the instructions, a science achievement test consisting of three subtests (knowledge, understanding, and application), a self-efficacy test, and a questionnaire about the perception of instruction were administered. The analysis of the results revealed that the scores of heterogeneous RPT group, regardless of the students prior science achievement level, were significantly higher than those of the other groups in the knowledge and understanding subtests, and the self-efficacy test. The scores of homogeneous RPT group were significantly higher than those of the comparison group in the knowledge subtest but not in the understanding subtest and the self-efficacy test. The low-level students in heterogeneous RPT group performed better in the science achievement test and the application subtest than those in the other groups. The high-level students in RPT groups performed better in the science achievement test than those in comparison group. However, there was no significant difference for the application subtest scores of the high-level students of the three groups. Most students in RPT groups perceived positively on the instructions. The students in heterogeneous RPT group and low-level students especially showed more positive perception of the instruction than those in homogeneous RPT group and high-level students.

• Journal of The Korean Association For Science Education
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• v.24 no.3
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• pp.481-498
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• 2004

The purpose of this study was to compare and analyse the subject organization and teaching units of middle school science curriculums and science textbooks, by studying the organization of subject matter and content scope and level of middle school science subject in South and North Korea. As a result of this study, the composition, scope, and level of content between middle school science textbooks in South and North Korea were similar. However, the study found that science education objectives, separated science curriculum subject organization, economical efficiency weighted format and organization of science subject matter, result-centered experiments, the enlightenment of Kim Ilsung and his son in North Korea science education were very far from the desirable direction of science education. Therefore, the view on level-based curriculum and organization of the science curriculum should be integrated, and preparation of student-centered organization of textbooks and expansion of science-technology-society content is needed before unification. And also, the united Korea science curriculum shouldn't simply compromise or neutralize between middle school science curriculum in South and North Korea. They should make a future-oriented plan for information and globalism society.

• Journal of Korean Home Economics Education Association
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• v.8 no.2
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• pp.1-14
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• 1996

Sex education in the U.K. follows an ideal model, co-operation where ever possible between homes, schools, and communities, whereas in Korea schools are mostly responsible for sex education. Moreover, Central Government and LEAs are deeply involved in school sex education in the U.K., in contrast, the concrete help at Government level is very limited in Korea though the necessity of sex education is acknowledged. These differences be accounted for by the different social and cultural backgrounds of the two countries, especially given the different thoughts of the people-oriental and occidental-. In the U.K., sex education has been a compulsory subject in secondary schools since 1994 (by the Education Act 1993), and it is well managed with the support at Government level as compared with that of Korea. Sex education in the U.K. may give some lessons for practising and developing sex education in Korea because the people in both countries have similarly conservative thinking about school sex education and it is implemented very carefully in the U.K.. In this article, a general comparison of background, policy, aims, content, management, teacher training, and materials of sex education between the two countries is made.

• Journal of Digital Convergence
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• v.16 no.10
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• pp.523-530
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• 2018

This study aimed to examine the association between betting games and problem gambling among adolescents, with attention paid to comparisons by gender and school level. For this purpose, this study analyzed a sample of 3,653 adolescents from the 2015 Survey on Youth Gambling Problems. The main findings are as follows. First, experiencing online betting games compared to non-online betting games was associated with higher risks of being light and severe problem gambling among adolescents. Second, the associations between online betting games and problem gambling was more pronounced for male adolescents than for female adolescents. Third, the associations between online betting games and problem gambling was more pronounced for high school students than for middle school students. Based on the findings, this study suggested practical strategies to prevent problem gambling among adolescents.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.291.1-291.1
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• 2016

Graphene by one of the two-dimensional (2D) materials has been focused on electronic applications due to its ultrahigh carrier mobility, outstanding thermal conductivity and superior optical properties. Although graphene has many remarkable properties, graphene devices have low on/off current ratio due to its zero bandgap. Despite considerable efforts to open its bandgap, it's hard to obtain appropriate improvements. To solve this problem, heterojunction barristor was proposed based on graphene. Mostly, this heterojunction barristor is made by transition metal dichalcogenides (TMDs), such as molybdenum disulfide ($MoS_2$) and tungsten diselenide ($WSe_2$), which have extremely thickness scalability of TMDs. The heterojunction barristor has the advantage of controlling graphene's Fermi level by applying gate bias, resulting in barrier height modulation between graphene interface and semiconductor. However, charged impurities between graphene and $SiO_2$ cause unexpected p-type doping of graphene. The graphene's Fermi level modulation is expected to be reduced due to this p-doping effect. Charged impurities make carrier mobility in graphene reduced and modulation of graphene's Fermi level limited. In this paper, we investigated theoretically and experimentally a relevance between graphene's Fermi level and p-type doping. Theoretically, when Fermi level is placed at the Dirac point, larger graphene's Fermi level modulation was calculated between -20 V and +20 V of $V_{GS}$. On the contrary, graphene's Fermi level modulation was 0.11 eV when Fermi level is far away from the Dirac point in the same range. Then, we produced two types heterojunction barristors which made by p-type doped graphene and graphene treated 2.4% APTES, respectively. On/off current ratio (32-fold) of graphene treated 2.4% APTES was improved in comparison with p-type doped graphene.

• International Journal of Highway Engineering
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• v.14 no.6
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• pp.93-101
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• 2012

PURPOSES : This study is to develop ISM for potential risk factor in School Zone. METHODS : Based on the literature review, the Analytic Hierarchy Process (AHP) has been used most widely. However, it is difficult to apply in practice because the AHP results have the characteristics of the independence between each element and the interlayer can not explain the interrelationship. The Network Analysis Process (ANP) is possible to analyze the relationship between the elements and the network through the feedback. But, the reliability of the analysis fall because of complicated pair of comparison, also it is difficult to solve the super matrix. In this study, the complicated relationship between each element is inquired through the Interpretive Structural Modeling (ISM). RESULTS : The methodology of ISM is developed to remove the children's potential risk factors in school zone. CONCLUSIONS : It is possible to remove the children's potential risk factors from low level to high level step by step and improve safety. Through this, risk factors can be removed from the low-level, and upper-level will automatically improve.

• Journal of the Korean Dietetic Association
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• v.11 no.1
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• pp.95-104
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• 2005

Customer satisfaction concerning foodservice quality characteristics were evaluated by using importance performance analysis(IPA) techniques in middle school foodsevice operations. One hundred students from each of 17 middle schools in Gangwon province were surveyed by self-developed questionnaire. Total of 1,675 questionnaires(female 943 and male 732 respectively) were collected and data were analyzed using SAS program. The results of this study are summarized as follows: 1.The male and female students scored the importance level as 3.99 and 4.03 out of 5 respectively, which means 'important' The performance level of female(2.71) was significantly lower than male(2.86) which means 'between bad and so-so'. it is suggested that the statistical analysis should be conducted respectively according to gender. And there is no performance level over 4(good). 2. Dissatisfied quality attributes identified were convenience of dinning room and the managerial attitude of dissatisfaction in the female and male students. 3. Satisfied quality attributes identified were hygiene of food and dinning room and spoon and cup and drinking water table and distribution process, taste of food, variety of food in the female and male students. 4. The performance scores of lower price(less than 1500 won) lunch group was higher than higher price(more than 1800 won) lunch group in the female and male students.