• Journal of Korea Foresty Energy
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• v.25 no.1
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• pp.1-8
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• 2006

This study was conducted to develope allometric equations and to estimate biomass, stem density, and biomass expansion factor for the three stand age classes (I-II, III-IV, and V-VI) of Japanese larch (Larix leptolepis) in Gapyeong area. Total dry weight (kg/tree) and aboveground biomass (ton/ha) were 57.8 and 71.1 for I-II class, 185.4 and 195.6 for III-IV class, and 1047.9 and 180.6 for V-VI class, respectively. Total above and belowground biomass (ton/ha) was 96.3 for I-II class, 265.7 for III-IV class, and 244.5 for V-VI class. The proportion (%) of stem to total biomass increased with stand age class and was 53.9 for I-II class, 55.7 for III-IV class, and 57.7 for V-VI class, respectively, while that of foliage decreased and was 7.1 for I-II class, 4.5 for III-IV class, 2.3 for V-VI class. Ratios of root to aboveground biomass were 0.35 for all age classes. Stem density ($g/cm^3$) differed between I-II class and III-VI class. Aboveground and total biomass expansion factors were 1.31-1.44 and 1.26-1.94. Our results showed that differences in stand density with stand age classes might influence allometric equation, stem density and ratios of aboveground biomass to stem biomass and total biomass to stem biomass (biomass expansion factors).

• The korean journal of orthodontics
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• v.29 no.3 s.74
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• pp.361-374
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• 1999

Intraoral filled type of orthodontic appliance can cause reversible or irreversible damages such as gingivitis, periodontitis, enamel decalcification, dental caries, root resorption, and pulpal changes. Such adverse effects are brought by increase in dental plaque as well as oral flora. Such an increase causes gingival inflammation and enamel decalcification. The purpose of this study is to get klowledge on initial changes in dental plaque, gingivitis, and enamel decalcification after bonding fixed orthodontic appliances according to time flow, gender, and sides(right/left) of premolar region. For control group, 48 students of dental college, Yonsei university(26 males, 22 females) were chosen; for experimental group, 73 orthodontic patients(36 males, 37 females) who will be treated with fixed appliances were chosen. All the subjects had no systemic disease, juvenile periodontitis and all the females had passed their ,menarche. Tooth brushing instruction was given to all the subjects prior to the experiment. For control group, plaque index, gingival index, and decalcification index were measured twice at 3 weeks interval ; for experimental group, the same was done prior to, 3, 6, 9 weeks after bonding fixed appliances. The following results were obtained: 1. In plaque index 3 weeks after placement of appliances, and it showed gradual increase afterwards. 2. In gingival index3 weeks after placement of appliances, and afterwards it showed increase at a faster rate than plaque index. 3. Enamel decalcification began to show between 3 and 6 weeks after bonding fixed appliances. Decalcification index began to increase 6 weeks after appliance placement, but there was no statistical significance. 4. When the comparison was made between two sides of premolar region, the right side showed greater index in plaque and gingival index of experimental group.

• The korean journal of orthodontics
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• v.29 no.6 s.77
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• pp.707-720
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• 1999

The purpose of this study was to evaluate racial differences In head posture and the influence of head posture to the craniofacial morphology. The sample group of this study was made up of 51 Korean males and 120 Scandinavian Caucasian males. From the comparison of the cranio-cervical angle and the variables of craniofacial morphology between them, the following results were obtained. 1. The cranio-cervical angle (NSL/OPT) was on average 9.28 degrees larger In Koreans. 2. The length of the anterior cranial base (N-S) was on average 4.66mm shorter in Koreans. 3. The length of the maxillary base (sp-pm and ss-pm) were on average 2.75mm and 4.65mm shorter in Koreans respectively, the anterior maxillary height (n-sp) was on average 2.60mm longer, the posterior dimension (s-pm) was found to be 2.06mm longer in Koreans, and the maxillary inclination (NSL/NL) was identical in both samples. 4. The mandibular body length (pg-tgo) and ramus height (ar-tgo) were identical in the two groups, but the genial angle (ML/RL) was 3.22 degrees smaller and the mandibular plane inclination (NSL/ML) was 2.44 degrees larger in Koreans 5. The maxillary prognathism (s-n-sp and s-n-ss) and the mandibular prognathism (s-n-sm) were identical in both samples. 6. The sagittal jaw relationship (ss-n-pg) was 1.44 degrees larger in the Korean sample, but the vortical jaw relationship (NL/ML) was not significantly different. 7. The anterior facial height (n-gn) was 5.57mm longer in the Korean sample. 8. The mandibular alveolar prognathism (CL/ML) was 5.71 degrees greater and the interincisal angle (ILs/ILi) was 3.08 degrees more acute in Koreans. Taken together these results, craniofacial morphology can be influenced by the head posture defined by cranio-cervical angulation.

• Journal of Korean Home Economics Education Association
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• v.23 no.4
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• pp.67-85
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• 2011

The purpose of this study was to find out how to operate Technology Home Economics in the 2009 revised national curriculum and Home Economics teachers perception on the current states in the middle schools, focused on intensive course-taking, block-time, and total hours to take the course. Data were collected from the 118 Home Economics teachers nationwide through e-mail from May 25 to June 4, 2011, and analyzed with frequencies, percentage, means, t-test, cross-tabulations, and ANOVA. The results showed that Technology Home Economics was intensively taken in the most of all schools(91.5%) during 4 semesters by senior and freshmen or junior. Teachers were relatively less involved in the decision making process for intensive course-taking than did the school managers and dissatisfied with the fact of intensive course-taking. But a few school adopted block-time and most teachers did not think it was necessary. Over half of schools offered the same 16 hours of Technology Home Economics as in the previous 2007 revised curriculum, but nearly 2 out of 5 schools reduced the hours from 1 to 8 with an average of 2.8 hours. To keep the necessary hours to teach the full contents of Technology Home Economics should be protected. The follow-up research needs to be conducted to investigate the changes in the perception of Home Economics teachers.

• Journal of Korean Home Economics Education Association
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• v.21 no.3
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• pp.29-43
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• 2009

The purposes of this study were to examine effective variables influencing on adolescents' mobile phone addiction. The subjects were the 666 middle or high school students who had their own mobile phone in Gwangju. Data were analyzed with frequency, percentage, cronbach's ${\alpha}$, mean, SD, pearson's correlation and multiple regression using SPSS/PC WIN 14.0 program. The major findings were as follows: 1. The most frequently used function of student mobile phones was text message and they used text message more than 41 times a day. Mostly they were talking to the same sex friends on the phone and the monthly charges ranged from 20,000 to 30,000 won. In general, they called to their friends after school. Their parents' attitudes toward their mobile phone using showed that the most of their parents did not care about their children's mobile phone use. The restriction of using their mobile phone at school was normal. 2. The average scores of mobile phone addiction were lower than median(3.0) and self esteem, self control, family strengths, peer conformity and school life adaptation were higher than median. 3. The adolescence's mobile phone additions were influenced by peer conformity, school life adaptation, school levels, sex and self control. And these variables explained to the adolescence's mobile phone additions about 28%.

• Journal of Korean Home Economics Education Association
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• v.21 no.3
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• pp.45-64
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• 2009

The purpose of this study was to develope issue-centered teaching learning process plan for environment-friendly housing education and to apply it to the housing section of Technology Home Economics in a middle school. PRO-CON cooperative group model was used for the teaching learning process plans of 2-session lessons according to the ADDIE model. In the development stage, 7 activity materials and 20 teaching learning materials (4 reading texts, 12 pictures and photos, & 5 moving pictures) were developed for 2-session lessons. The plans applied to the 7 classes, 222 students, in the third grade of the G middle school in Gyeonggi-do during July 10th-17th, 2008. The results showed that the final pro-con was influenced by the rationals of juries' pro-con of each team and the representative's discussion besides one's environmental perspective. The intention to implement environment-friendly housing activities was significantly increased between before and after the lessons. The contents, methods, goals, and process of the 2-session lessons were evaluated over medium to somewhat higher levels. Those evaluations except methods and general satisfaction with the lessons were differed by sex, students' and their families' interests in environments but not by the type of housing. These results might support that pro-con cooperative group model of controversial issues on parking lot would be appropriate to environment-friendly housing lessons and could apply to broad issues on housing and various schools in other areas.

• Journal of Korean Home Economics Education Association
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• v.22 no.3
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• pp.19-36
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• 2010

The objective of this study was to measure the critical thinking level of activity tasks included in home economics textbooks published under the 2007 Revised National Curriculum. For this purpose, we sampled 3 kinds of Technology-Home Economics textbooks for 7th graders, selected activity tasks contained in the textbooks, and classified them by type. A total of 93 activity tasks were extracted, and they were analyzed using 9 questions on critical thinking prepared based on Kim Young-jung's '9 Elements and 9 Standards of Critical Thinking.' The results of this study were as follows. First, the total score of the critical thinking level of activity tasks in the home economics textbooks was 66.8, which was not high enough to induce learners' critical thinking. Among the sub-categories of critical thinking, the score was high in order of argumentative thinking(83.9), analytical thinking(78.1), and dialectic thinking(38.3). As in the results, the activity tasks were particularly inadequate for inducing dialectic thinking. Second. in the results of analyzing difference in the critical thinking level according to unit, significant difference was observed among the units. Activity tasks in Units 'Adolescents' Self-management'(77.8), 'Adolescents' Consumption life'(75.2), and 'Adolescents' Sex and Peer Relationship'(71.1) induced critical thinking more effectively than those in other units, but activity tasks in Units 'Clothing and Self-expression' (61. 4), 'Adolescents' Development'(60.0), and 'Adolescents' Nutrition and Meals'(59.6) were inadequate for inducing critical thinking. Third, in the results of analyzing difference in the critical thinking level according to activity task type, the level was high in order of 'Inquiry Activities' (75.7), 'Discussions' (74.6), 'Practical Activities'(65.4), and 'Trials' (50.7), and the differences were significant. That is, among activity task types, 'Inquiry Activities' were most effective in inducing learners' critical thinking and 'Trials' were least effective.

• Journal of Korean Home Economics Education Association
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• v.19 no.1 s.43
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• pp.99-114
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• 2007

This study aims at investigating how middle school students perceive the content of the 'Me and My Family Relations' unit in the technology and home economics textbook, act on such perceptions and how this connects with their healthy family relations. In addition, the study also points at inquiring into what kind of differences and mutual influences can be found in the above-mentioned three factors according to family environment. With this objective. this research has analyzed survey data conducted on 401 7th grade middle school students residing in Incheon Greater city, collected by the random sampling method. The findings are as follow: First, the students were found to have positive perceptions on the 'family relations and communication' unit in the technology and home economics text book. However. they were also found to perceive that the content was not as realizable in their everyday family lives. Second, the number of students who perceived their family lives to be healthy was found to be quite high. The students perceived their family lives to be healthy projecting from such aspects as the degree of gratification and affection, extent of family bonding, communication patterns, and problem solving abilities, in the same order. In addition, the higher the families' socio-economic level, and in the cases that the students had working mothers and the fathers held higher degrees, the degree to which the families were perceived to be healthy was higher. Third, in investigating the influence that such factors as the students' family environment, the degree that students perceived the text book content positively, and the degree that the students perceive the content to be realizable have on healthy family relations, among these factors, the students' perceived degree of how healthy their family relations are had the most bearing over the above-mentioned factors. The second influential factor on how healthy family relations are was the family's affectional environment, found to be more influential than such factors as family type, the mother's employment status, living standards, and the parents' educational level. On the other hand, the perceived level of realizability was found to have a lower influence on the students' family relations than the perceived positivity.

• Journal of Korean Home Economics Education Association
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• v.26 no.1
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• pp.119-134
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• 2014

This research looks at the effects of portfolio-based lessons to help female middle school students understand and develop their self identity, and to examine the influence of various factors within the school and home environment. The participants were 256 female middle school students in Gangneung-si, Gangwon-do and the analysis was done using the SPSS/WIN 12.0 program. The 6 portfolio-based teaching lessons were made with the aim of developing each subordinate scope in every module for development of self-receptiveness, uniqueness, closeness, tendency of planning the future, and independence. Results of the pre and post-test revealed that scores of self-receptiveness and uniqueness increased. Content analysis revealed that the students pursued their talents and interests through the portfolio activities, and made specific plans for their future careers. In sum, the results demonstrate that the students became specifically and systematically concerned about their future career. The results of hierarchical regression showed that self-receptiveness developed when their parents' attitudes were not rejecting and their peer relationships were positive. Uniqueness was shown to develop as the fostering attitudes of parents were receptive. Closeness developed as fostering attitudes of parents were receptive and as their relationships with peers were positive. The students' tendency to plan the future developed as fostering attitudes of parents were receptive and as their relationships with teachers were good, and independence was shown to develop as the fostering attitudes of parents were not rejecting. Results of a two-year follow-up study appeared that self-receptiveness scores decreased as time passed, so students had highest scores in their first year and lowest scores in their third year. Scores of uniqueness, tendency of planning the future, and identity increased in the students' second year and then remained steadily afterward.

• Journal of Korean Home Economics Education Association
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• v.26 no.1
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• pp.101-118
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• 2014

"Career maturity" is very crucial for high school students since it has an impact on their career path and decision-making. Not only that, it is also important in self-realization and happiness as well as maximizing human resources. When it comes to understanding high school students' career path, it is necessary to know how they perceive school life since they spend most of their time in school. It's also vital to observe in the perspective of students' personal growth. This study seeks to understand the relationship between "adaptation to school life" "self-esteem" and "career maturity". To accomplish this, the 7th additional surveys conducted by Welfare Panel Study were used. The survey was conducted among 496 high school students in order to come up with descriptive statistics and correlation between "adaptation to school life" and "self-esteem" as well as the level of "career maturity". Hierarchical multiple regression analysis was used to understand the effects of "adaptation to school life" and "self-esteem" on "career maturity." The Baron and Kennny mediation analysis were used to understand the effects when the mediating role of "self-esteem" comes into the relationship between "adaptation to school life" and "career maturity". The results of the analysis are as follows: First, the average age for high school students' "career maturity" is 2.07, while it is 1.91 for "self-esteem". For "adaptation to school life," the relationship between "obedience to school regulations" and "relationship with friends" was relatively higher than the relationship between "attitude toward school life" and "interest in school life" Second, high school students' "career maturity" "adaptation to school life" and "self-esteem" were thought to be statistically meaningful since it showed that they had a positive relationship with each other. Third, "interest in school life" "attitude toward school life" and "obedience to school life" and "relationship with friends" in which all of these are the sub factors for "adaptation to school life" together with "self-esteem" had an influence on high school students' "career maturity". Lastly, the relationship between "adaptation to school life" and "career maturity" was proved to be influenced by the partial mediating role of "self-esteem". As the study seeks to find relationships and the factors that affect high school students' "career maturity" meaningful information is given out for the development and progress of educational programs for "career maturity". This was done by understanding the fundamental and systematic approach towards "career maturity" in the students' perspective.