• The Journal of the Korean dental association
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• v.19 no.1 s.140
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• pp.67-71
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• 1981

This study was undertaken to find out the characteristic craniofacial morphology of Class II Division 2 malocclusions in children by means of roentgenocephalometry. The subjects consisted of twelve boys and thirteen girls with Class Ii, Division 2, thirty seven boys and fifty three girls with Class II, Division 1, and forty six boys and eighty one girls with normal occlusion, ranged from 10 years old to 18 years old. The following results were obtained; 1. The anteroposterior relationship of the maxilla to the cranium in the Class II, Division 2 malocclusion similar to the normal occlusion, but the mandible was the posterior position in th the cranial anatomy. 2. There were no significant differences in the anteroposterior relationship of the maxilla and the mandible between Class II, Division 1 and Class II, Division 2 malocclusions. 3. In Class II, Division 1 the axes of maxillary incisors showed labial inclination, but lingual inclination in Class II, Division 2 malocclusions. 4. Overbite was prominent one in Class II, Division 2, on the other hand overjet was distinguished in Class II, Division 1.

• The korean journal of orthodontics
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• v.51 no.6
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• pp.407-418
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• 2021

Objective: To investigate differences in the heritability of skeletodental characteristics between twin pairs with skeletal Class I and Class II malocclusions. Methods: Forty Korean adult twin pairs were divided into Class I (C-I) group (0° ≤ angle between point A, nasion, and point B [ANB]) ≤ 4°; mean age, 40.7 years) and Class II (C-II) group (ANB > 4°; mean age, 43.0 years). Each group comprised 14 monozygotic and 6 dizygotic twin pairs. Thirty-three cephalometric variables were measured using lateral cephalograms and were categorized as the anteroposterior, vertical, dental, mandible, and cranial base characteristics. The ACE model was used to calculate heritability (A > 0.7, high heritability). Thereafter, principal component analysis (PCA) was performed. Results: Twin pairs in C-I group exhibited high heritability values in the facial anteroposterior characteristics, inclination of the maxillary and mandibular incisors, mandibular body length, and cranial base angles. Twin pairs in C-II group showed high heritability values in vertical facial height, ramus height, effective mandibular length, and cranial base length. PCA extracted eight components with 88.3% in the C-I group and seven components with 91.0% cumulative explanation in the C-II group. Conclusions: Differences in the heritability of skeletodental characteristics between twin pairs with skeletal Class I and II malocclusions might provide valuable information for growth prediction and treatment planning.

• The korean journal of orthodontics
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• v.42 no.4
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• pp.182-189
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• 2012

Objective: The aims of this study were to use a 3-dimensional (3D) system to compare molar relationship assessments performed from the buccal and lingual aspects, and to measure differences in occlusal contact areas between Class II and Class I molar relationships. Methods: Study casts (232 pairs from 232 subjects, yielding a total of 380 sides) were evaluated from both the buccal and lingual aspects, so that molar relationships could be classified according to the scheme devised by Liu and Melsen. Occlusal contact areas were quantified using 3D digital models, which were generated through surface scanning of the study casts. Results: A cusp-to-central fossa relationship was observed from the lingual aspect in the majority of cases classified from the buccal aspect as Class I (89.6%) or mild Class II (86.7%). However, severe Class II cases had lingual cusp-to-mesial triangular fossa or marginal ridge relationships. Mean occlusal contact areas were similar in the Class I and mild Class II groups, while the severe Class II group had significantly lower values than either of the other 2 groups (p < 0.05). Conclusions: Buccal and lingual assessments of molar relationships were not always consistent. Occlusal contact areas were lowest for the Class II-severe group, which seems to have the worst molar relationships - especially as seen from the lingual aspect.

• The korean journal of orthodontics
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• v.14 no.1
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• pp.33-37
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• 1984

The prevalence of normal occlusion and malocclusion was assessed by Angle's Classification method for 8989 school students at 7-22 years in Seoul. The occurrence of malocclusion and the need-for orthodontic treatment was 61 per cent among them. Results indicated no significant differences between the sexes for the occlusal relationships of the mandible to the maxille. The prevalence of Class I, Class II, and Class III malocclusion in all malocclusion was shown to be Class I, 45.7 per cent; Class II, 7.6 per cent; and Class III, 7.9 per cent. Class II Division 1 was observed to occur four times frequently compared to Class II Division 2 in Class II malocclusions. Class III malocclusion was shown to occur more frequently compared that of Caucasians.

• 대한공업교육학회지
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• v.37 no.1
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• pp.65-85
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• 2012

This study focuses on the 'invention technique and practical experience' unit to observe how the colleague mentoring class has its effect on self-efficacy. For this, we have selected experimental group and comparative group and proceeded the experiment. For five classroom hours of the 'technique of invention and practical experience' unit, each group was assigned different method to do the experiment. The experimental group was applied with the colleague mentoring method and the comparative group was applied with the self study method. To observe the differences of how it effects on one's self-efficacy, the questionnaire was distributed before and after class. Then, it was verified for the meaningful differences between the two groups. To summarize, the results are as follows. First, for self-efficacy experiment, the questionnaire before the experiment showed that there were no differences found between two groups. However, the questionnaire collected after the experiment showed great differences. The group with the colleague mentoring showed more meaningful differences at p<.05 significance level than comparative group. Furthermore, by observing the before and after questionnaire, it was found that both groups showed statistically meaningful differences at p<.05 significance level, but the experimental group showed greater self-efficacy improvements than comparative group. Second, when further examining the self-efficacy, the activity start expectation, activity continuation expectation, activity performance expectation, and experience recovery expectation showed the statistically meaningful differences at p<.05 significance level. According to the above results, it can be stated that the colleague mentoring class has more positive effects on the self-efficacy than self-study class. Summing up, the colleague mentoring class is more effective than self-study for fostering student's self-efficacy.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.1
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• pp.256-263
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• 2014

This research aims is to confirm the influence of a teacher's teaching style and teaching career on instructional analysis. Through this, the differences in the relevant elements' view points on a class and those in teachers' analysis view points on class criticism and instructional analysis at the education field can be investigated. For this study, the teaching styles of 198 elementary school teachers were categorized, their teaching careers were checked as teaching career and set them as covariate, and the differences in the view points on the analysis of the class climates were verified depending on each teaching style. As the research result, meaningful differences were found in four areas of the elements of class climates analysis, that is, creativity, vitality, precision, and gentleness. In the analysis of the class climates, the teachers with a professional style among the teaching styles gave the highest grades to creativity in the same class, those with a facilitating style to vitality, those with a role model style to precision, and those with a facilitating and role model style to gentleness. On the other hand, those with an authoritative and a delegating style were proved to give the lowest grades in general class climates. It means that teachers with different teaching styles have different viewpoints when analyzing a class, and those with a professional, a role model and a facilitating style have a relatively stronger intention to analyze a class through reflective introspection and permissive recognition.

• The korean journal of orthodontics
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• v.20 no.3 s.32
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• pp.519-539
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• 1990

It is the aim of this study to observe the distribution of various facial types in class III malocclusion and to characterize the craniofacial features of the very facial types. Cephalometric headptates of a hundred and ten persons showing bilateral class III malocclusion whose mean age was 12.51 years and sixty nine persons of normal occlusion whose mean age was 12.23 years were measured and statistically analyzed. The following summary and conclusions were drawn. 1. Affording the bases for SNA and SNB, $35.45\%$ of sample showed normally positioned maxilla and protruded mandible, $30.00\%$ for retruded maxilla and normally positioned mandible, $15.45\%$ for retruded maxilla and protruded mandible, $10.90\%$ for both maxilla and mandible within normal range and $8.20\%$ for miscellaneous types were arranged in class III malocclusion. 2. $52.72\%$ of sample showed neutrodiveigent, $35.45\%$ for hyperdivergent and $11.81\%$ manifested hypodivergent mandible in class III malocclusion. 3. Providing the bases for facial and mandibular planes, $33.63\%$ of sample showed prognathic and neutrodivergent, $20.90\%$ for mesognathic and hyperdivergent, $17.27\%$ for prognathic and hyperdivergent and $15.45\%$ for mesognathic and neutrodivergent were arranged in class III malocclusion. 4. The class III malocclusion brought out shorter cranial base, smaller saddle angle, and larger articular and genial angle. It showed retropositioned maxilla and forward positioned mandible in spite of no significant differences in linear measurements of mandible. Anterior lower facial height was significantly larger in class III malocclusion, while posterior total facial and anterior total facial heights exhibited no significant differences. 5. It is suggested class III malocclusion was attributed to shorter cranial base, smaller saddle angle, maxillary deficiency and/or retrusion, mandibular excess and/or protrusion, excessive vertical growth of the anterior lower face, and their complex as well.

• Journal of Engineering Education Research
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• v.26 no.5
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• pp.3-16
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• 2023

This study was to investigate the operation status and the students' perception for both theory-focused and practice-focused online class in engineering college that were implemented in responses to COVID-19. For this purpose of the study, the survey including the open-ended questions were conducted to the 147 students in college of engineering in 2021 at one of the universities located in the metropolitan area. The survey were analyzed by SPSS 26.0 and then findings were as follows. First, while the most students were satisfied with the operation of online classes that were implemented in response to COVID-19, many students were unsatisfied with the practice-focused online class. Also, there were some differences in the level of students' satisfaction for some factors of online class operation in terms of the students' background. Second, there were significant differences in some parts of students' satisfaction in terms of the background of students. specifically, males students were more satisfied with the supports of teaching assistant in online classes than female students and the junior and senior levels of students are more satisfied with the teaching strategies of online classes than freshman and sophomore year students. Third, the level of students' satisfaction was different in terms of the types of online platforms as well as the methods of communication between students and professors. Finally, even though the students in the college of engineering understand the benefits in the online classes, they indicated the limitations and difficulties for participating in practice-focused online class and demanded the improvement of the operation for the online lab classes. The further research needs to be conducted to investigate the status of operation for online lab and practice classes in college of engineering.

• Journal of the Korean Home Economics Association
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• v.28 no.4
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• pp.103-117
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• 1990

The purpose of this study was to investigate the difference of mid-life family stress and family coping strategies according to conjugal sex and social class. This study was also intended to examine the relations between mid-life family stress and family coping strategies. The subjects of this study were 150 married couples(300 persons) who were 40 to 59 years old in Seoul. McCubbin, Wilson & Patterson (1979)'s "Family Inventory of Life Events and Changes" and McCubbin, Larsen & Olson (1982)'s "Family Coping Strategies" were used to gather data for the study. For the statistical analysis of data, factor analysis, T-test, Duncan's multiple Range Test, Pearson's r and cronbach's α for reliability were performed. The major results of this study were summarized as follows; 1. There were significant differences according to conjugal sex and social class in family stress; Wives reported more family stress than husbands. And the lower social class of the family, the more family stress were found. 2. There were some significant differences according to conjugal sex and social class in family coping strategies; Wives reported more family coping strategies than husbands in "freind and neighbor's support", "religious support". And the lower social class of the family, the more "passive attitudes" were found. 3. There were some significant correlations between family stress and family coping strategies; The higher extent of the total family stress, the lesser positive attitudes were found.

• Journal of Engineering Education Research
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• v.24 no.2
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• pp.41-50
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• 2021

This study was conducted with the aim of exploring ways to more effectively manage related courses by checking the educational effects of the operation of engineering liberal arts courses operated for the development of communication skills of engineering students by detailed factors of communication skills. To achieve the purpose of the study, literature review and survey methodologies were used. A survey was conducted before and after class targeting four class students of the engineering college of D University in Gyeonggi-do. As a result of comparing the results of the pre-test before class through this class and the results of the post-test conducted at the end of the class, it was confirmed that speaking ability, reading ability, and communication ability were improved at a statistically significant level. In addition, as a result of analyzing differences in communication competencies for each individual variable, it was found that there were statistically significant differences according to gender, students' major field, and grade. Based on such research results, several educational proposals were presented to increase the effectiveness of the management of courses operated to develop communication skills.