• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.22 no.3
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• pp.182-191
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• 2011

Objectives: The aim of this study was to investigate the sleep patterns of South Korean elementary school children and whether the differences in sleep patterns were related to behavior, emotional problems, attention and academic performance. Method: This study included a community sample of 268 boys and girls from fourth-, fifth- and sixth-grade classes in a South Korean metropolitan city from November to December 2010. The primary caregivers completed a questionnaire that included information on demographic characteristics, as well as the Child's Sleep Habit Questionnaire (CSHQ), the Korean version of Child Behavior Checklist (K-CBCL), the Korean version of the Learning Disability Evaluation Scale (K-LDES), the Korean version of ADHD Rating Scale (K-ARS) and the Disruptive Behavior Disorder Scale (DBDS). We conducted analyses on the CSHQ individual items, between the subscales, on the total scores and on the K-CBCL, the K-LEDS, the K-ARS and the DBDS. Results: Based on the findings from the CHSQ, the subjects had significantly higher scores for bedtime resistance ($9.18{\pm}2.17$), delayed sleep onset ($1.32{\pm}0.62$), the sleep duration ($4.19{\pm}1.52$) and daytime sleepiness ($14.10{\pm}3.55$) than the scores from the previous reports on children from western countries. The total CHSQ score showed positive correlations to all subscales of the K-CBCL : withdrawn (r=0.24, p<.005), somatic complaint (r=0.24, p<.005) and anxious/depressive (r=0.38, p<.005). Bedtime resistance was associated with oppositional defiant disorder (r=0.15, p<.05) and a positive correlation was demonstrated between sleep anxiety and the oppositional defiant disorder score (r=0.13, p<.05), night waking and the conduct disorder score (r=0.16, p<.05). Delayed sleep onset was related with low performance on the K-LDES with respect to thinking (r=-0.17, p<.05) and mathematical calculation (r=-0.17, p<.05). Conclusion: The results of this study reconfirm Korean children's problematic sleep patterns. Taken together the results provide that the reduced sleep duration and disruption of sleep pattern can have a significant impact on emotion, behavior, performance of learning in children. Further studies concerning more diverse psychosocial factors affecting sleep pattern will be helpful to understanding of the sleep health in Korean children.

• Journal of the Korean Society of School Health
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• v.8 no.2
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• pp.233-243
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• 1995

A survey has conducted on two hundred high school students of the first and second grade by way of questionnaine in Seoul. The purpose of this study on the information from the survey is to cstimate the level of awareness and probe how they feel and what they wish on sex. X2 inspection is designed to assess general aspects of responded contents by way of percentage and examine degree of satisfaction on previously experienced sex education and demand for sex education. The result is as follows. 1. As a result of the examination of degree of awareness on sex of respondents, 62% delines sex as human relationship including moral values for harmony between men and women. 64% of the men and 70% of the women say that sex is a natural thing. It comes to the conclusion that most of the respondent sgenerally consider sex positive. On chastity, 68.5% of the respondent answer that it means physical chastity, 12.5% that chastity before marriage should be kept, and 43% that it should be kept as far as possible. Most of them pespond that it should be kept. 2. As a result of the examination on the contents of sex, they answer they know well in the order of masturbation(72%), pregnancy(76%), and sex(63%). Contraception, abortion and ejection are contents they poorly informed of. 3. As a result of the examination on experienede of sex education, 83% of men and 100% of women have experienced sex, education, but their degreeof satisfaction to it is very low. And 49% of the whole is dissatisfactory to it. There is some difference between male and female students.(p=0.000) That result translates that female studeuts are educated on sex tjhrough more systematic subjects than male ones. In addition, it turns out that teenagers get most information on sex through friends, seniors, and mass media such as videos, TV and radios. Correct and systematic sex education is need because wrong information on sex culd be taught and bring them to misbehave. 4. 87.5% of the respondents answer that sex education is necessary, so that degree of necessity for sex education, turns out to be very high. Also the main subject that should perform sex education is in the order of school(50%), Society(24.5), home(18.5%). They respond that most appropriated period for the beginning of sex education is about elementary school age(43%), and 34% believes it to be put ahcad of elementary school age. Anurse teacher accounts for 54% for the main subject that addresses sex education, to male students visit teachers are most favored for 50%. As a result of those, it could be concluded that most high school students want sex education from responsible persons who have systematic and professional knowledge on sex. 5. In order to perform proper sex education by the above results, better educational effects are obtained when characteristics and natures of teenagers are known and most wanted knowledge by them is taught in priority in times of planning sex education. Besides, the contents of sex education suitable for each school should be planned before elementary school age and sex education should be performed in accordance with students' demand. In addition, sex education should be attentively performed by home, all organizations of society as well as school. Therefore, sex education will play a great role in making teenagers reestablish their conception on sex when the traditional and moral value systems of our country and the new value systems which are being formed under the influence of the western culture are in harmony.

• Journal of the Korean Chemical Society
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• v.50 no.6
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• pp.494-505
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• 2006

This study was performed for 7th grade students to analyze by leader style, the verbal interactions between students in a small group in an MBL(Microcomputer-Based Laboratory) experiment class. The study was performed after arranging the students into four kinds of groups, including groups with leaders of inclusive, persuasive, and alienating styles and a group with no clear leader. The analysis of total frequencies of verbal interaction revealed that the group with an inclusive leader showed the highest frequency of verbal interaction, followed by the group with a persuasive leader, an alienating leader and lastly, the group with no clear leader. The group with an inclusive leader showed the highest frequency of interaction from a cognitive aspect related to question(Q), response(R), making suggestion(MS), and receiving opinions(RO), while interactions from an affective aspect related to behavioral participation(BP) and students' attitudes(SA) were observed more often in a group including an alienating leader than in any other group. An analysis of characteristics of verbal interaction according to leader style showed that a group with an inclusive leader had a permissive atmosphere. It also showed that all members of the group actively participated in discussion and they had a sense of belonging and self-pride with their group. In a group with a persuasive leader, the leader took the lead of most experimental and discussion activities and he was rarely challenged by other students in the group. Rather, other group members showed a tendency to depend on their leader. In a group with an alienating leader, the relationship between leader and members of the group was not harmonious and unfiltered expressions of dissatisfaction and ignorance often took place. The leader's lack of concern about members' low achievement became an obstacle in active discussion. In a group with no clear leader, most interactions during discussion were short and simple. Many answers to the question given by their members were not clear and the interactions were sometimes interrupted for a short while.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.2
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• pp.169-181
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• 2007

Statement of problem: Titanium is well known as a proper metal for the dental restorations, because it has an excellent biocompatibility, resistance to corrosion, and mechanical property. However, adhesion between titanium and dental porcelains is related to the diffusion of oxygen to the reaction layers formed on cast-titanium surfaces during porcelain firing and those oxidized layers make the adhesion difficult to be formed. Many studies using mechanical, chemical and physical methods to enhance the titanium-ceramic adhesion have been actively performed. Purpose: This study meant to comparatively analyse the adhesion characteristics depending on different titanium surface coatings after coating the casts and wrought titanium surfaces with Au and TiN. Material and method: In this study, the titanium specimens (CP-Ti, Grade 2, Kobe still Co. Japan) were categorized into cast and wrought titanium. The wrought titanium was cast by using the MgO-based investment(Selevest CB, Selec). The cast and wrought titanium were treated with Au coating($ParaOne^{(R)}$., Gold Ion Sputter, Model PS-1200) and TiN coating(ATEC system, Korea) and the ultra low fusing dental porcelain was fused and fired onto the samples. Biaxial flection test was done on the fired samples and the porcelain was separated. The adhesion characteristics of porcelain and titanium after firing and the specimen surfaces before and after the porcelain fracture test were observed with SEM. The atomic percent of Si on all sample surfaces was comparatively analysed by EDS. In addition, the constituents of specimen surface layers after the porcelain fracture and the formed compound were evaluated by X-ray diffraction diagnosis. Result: The results of this study were obtained as follows : 1. The surface characteristics of cast and wrought titanium after surface treatment(Au, TiN, $Al_2O_3$ sandblasting) were similar and each cast and wrought titanium showed similar bonding characteristics. 2. Before and after the biaxial flection test, the highest atomic weight change of Si component was found in $Al_2O_3$ sandblasted wrought titanium(28.6at.% $\rightarrow$ 8.3at.%). On the other hand, the least change was seen in Au-Pd-In alloy(24.5at.% $\rightarrow$ 9.1at.%). 3. Much amount of Si components was uniformly distributed in Au and TiN coated titanium, but less amount of Si's was unevenly dispersed on Al2O3 sandblasting surfaces. 4. In X-ray diffraction diagnosis after porcelain debonding, we could see $Au_2Ti$ compound and TiN coating layers on Au and TiN coated surfaces and $TiO_2$, typical oxide of titanium, on all titanium surfaces. 5. Debonding of porcelain on cast and wrought titanium surface after the biaxial flection is considered as a result of adhesion deterioration between coating layers and titanium surfaces. We found that there are both adhesive failure and cohesive failure at the same time. Conclusion: These results showed that the titanium-ceramic adhesion could be improved by coating cast and wrought titanium surfaces with Au and TiN when making porcelain fused to metal crowns. In order to use porcelain fused to titanium clinically, it is considered that coating technique to enhance the bonding strength between coating kKlayers and titanium surfaces should be developed first.

• Journal of The Korean Association For Science Education
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• v.34 no.3
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• pp.285-294
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• 2014

This study investigates the effects of formative assessment utilizing mobile applications on interest and self-directedness in science instruction. The study subjects are two 6th grade classes from H elementary school located in Incheon, and the experimental group and the comparative group are composed of 21 students, respectively. The students from the experimental group have been taught with mobile devices while the comparative group has been taught in methods consistent with the current teaching standards. For the sake of research, the results of the method applied to the mobile device focus group have been edited using Google Drive Forms, entered as QR codes and stored in order for them to later be utilized for teaching and learning process. In the process, the teacher has provided the students with feedback based on their answers. The students of comparative group are to solve the same formative assessment in paper. As a result, the teacher of the mobile device focus group has been able to go through twenty-nine questions on formative assessment in the teaching and learning process, confirm the correct answers five times and provide feedback twenty-five times for additional explanation. In the inquiry about interest, the mobile device group scored 4.64 points and the standard one scored just 1.99 points (p<0.01). Fifteen students answered in the interview that and the major reason why they scored high has been because it was fun to study with mobile devices. When it comes to self-directedness over the process of teaching and learning, the mobile device focus group has answered positively but the standard group has scored relatively low (p<0.01).

• Journal of Hospice and Palliative Care
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• v.11 no.3
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• pp.140-146
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• 2008

Purpose: Sooner of later, end-of-life care decision-making will unfold and be settled during the professional lives of medical students. However, there is prevalent ambiguity and uncertainty between the palliative treatment and euthanasia. We conducted this survey to investigate attitudes of medical students towards end-of-life making decisions, and to find out which factors primarily influenced the attitudes. Methods: A study was conducted among medical students at one university, the Republic of Korea. A written questionnaire was sent to all the 1st, 2nd, and 3rd-year medical students. It presented 5 statements on end-of-life decision-making. Students were asked whether they agreed or disagreed with each statement. Results: The response rate was 74.4%, and 267 questionnaires were analyzed. Percentages of agreement with each statements on Voluntary active euthanasia (VAE), Physician assisted suicide (PAS), Withholding life-sustaining management, Withdrawing life-sustaining management, and Terminal sedation (TS) was 37.1%, 21.7%, 58.4%, 60.3%, and 41.6%, respectively. The grade of students, religious activity, and educational experience were determinant factors. Agreement on each statements was higher in the low religious activity group than in the high religious activity group. Agreement on TS was higher among 3rd year students during their clerkship than among 1st and 2nd year students. Age of students and the experience of dying-people care had no significant influence. Conclusion: In end-of-life decision-making, religious and educational factors influenced medical students' attitudes. Especially, the experience of education during clerkship had significant influence on the attitude. Proper teaching on end-of-life decisions should further be considered during medical students' clerkship.

• Journal of Chest Surgery
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• v.36 no.9
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• pp.646-650
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• 2003

Many surgical techniques for ischemic mitral regurgitation (IMR) have been used with their excellent results and advantages. Here, we report our simple posterior annuloplasty techniques using vascular graft strip with their early results. Material and Method: Twenty two patients (13 male) underwent the operations for IMR (excluding the papillary muscle rupture) from December 2001 to January 2003. Preoperative risk factors were low ejection fraction (<35％, n=9), hypertension (n=13), diabetes (n=9), and renal failure (Cr>2.5, n=4). The wide dissection beneath the both vena cavae and interatrial groove after bicaval cannulation enabled the easy exposure of mitral valve even in the small left atrium. After eight or nine interrupted sutures in posterior annulus for anchoring the 6 mm width vascular graft strip, symmetric (n=8) or asymmetric (n=14) annuloplasty were done. Combined surgeries were CABG (n=21), Dor procedures (n=3), tricuspid valve annuloplasty (n=1), Maze operation (n=1), and aorto-right subclavian artery bypass (n=1). Result: Except for one surgical mortality, all the patients were doing well and the mean grade of regurgitation was decreased from 2.95 to 0.88, however the ejection fraction had not changed significantly just before discharge. Post-operative valve function evaluated before discharge revealed no residual regurgitation in 8 (including 1 patient with mild stenosis due to over reduction), minimal in 11, mild in 2, and mild to moderate regurgitation in 1. One patient who had ischemic cardiomyopathy and renal failure died of the arrhythmia during the hemodialysis. Conclusion: These observations suggest that the annuloplasty with vascular graft strip could be a safe and cost effective techniques for ischemic mitral regurgitation. However, the long term evaluation for the mitral valve function should be defined for the final conclusion.

• Journal of Korean Home Economics Education Association
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• v.23 no.3
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• pp.69-90
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• 2011

To develop the descriptive evaluation questionnaire with high validity and reliability on the Clothing and Textiles section of the middle school Technology & Hone Economics textbook, apply it to students and analyze its results. We made out a draft for descriptive evaluation questionnaire that was based upon the concrete establishment of the goal and the range of evaluation. We also made a rubric for scoring as well as sample answer-sheets. Finally, we completed a total of twenty three descriptive evaluation questions and we applied it to sixty five 2nd-grade students in two classes in a middle school. Descriptive evaluation questionnaire exhibited the relative high validity on each question. Moreover, three graders gave the same score on each question of descriptive evaluation, suggesting that descriptive evaluation questionnaire has the high inter-grader reliability and the strong correlation. But, low academic achievement was generally observed in the subjects. They had difficulty in describing their knowledge via their own language and drawing up accurate and detailed answers. They recognized the positive aspects of descriptive evaluation questionnaire, but they felt it uncomfortable due to study-burden and description itself. To overcome these limitations, it is required that students should experience various materials related to subject contents in classes as well as textbooks, concentrate themselves on finding solutions for problems, expand their scope, and practice describe them in advance. Therefore, the additional training for description evaluation questionnaire will be necessary for the more efficient and discriminative questionnaire. Also the questionnaire with high validity and reliability should be developed and the aggressive and voluntary participation of teachers will be needed.

• Journal of the Mineralogical Society of Korea
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• v.15 no.4
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• pp.329-344
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• 2002

Mineralogical and chemical characterization of some domestic bentonites, such as quantitative XRD analysis, chemical leaching experiments, pH and CEC determinations, were done without any separation procedures to understand their relationships among mineral composition, characteristics, and cation exchange properties. XRD quantification results based on Rietveld method reveal that the bentonites contain totally more than 25 wt% of impurities, such as zeolites, opal-CT, and feldspars, in addition to montmorillonite ranging 30～75 wt%. Cation exchange properties of the zeolitic bentonites are deeply affected by the content of zeolites identified as clinoptilolite-heulandite series. Clinoptilolite is common in the silicic bentonites with lighter color. and occurs closely in association with opal-CT. Ca is mostly the dominant exchangeable cation, but some zeolitic bentonites have K as a major exchangeable cation, The values of cation exchange capacity (CEC) determined by Methylene Blue method are comparatively low and have roughly a linear relationship with the montmorillonite content of the bentonite, though the correlated data tend to be rather dispersed. Compared to this, the CEC determined by Ammonium Acetate method, i.e.‘Total CEC’, has much higher values (50～115 meq/100 g). The differences between those CEC values are much greater in zeolitic bentonites, which obviously indicates the CEC increase affected by zeolite. Other impurities such as opal-CT and feldspars seem to affect insignificantly on the CEC of bentonites. When dispersed in distilled water, the pH of bentonites roughly tends to increase up to 9.3 with increasing the alkali abundance, especially Na, in exchangeable cation composition. However, some bentonites exhibit lower pH (5～6) so as to regard as ‘acid clay’. This may be due to the presence of $H^{＋}$ in part as an exchangeable cation in the layer site of montmorillonite. All the works of this study ultimately suggest that an assesment of domestic bentonites in grade and quality should be accomplished through the quantitative XRD analysis and the ‘Total CEC’measurement.

• Journal of the Korean Society of Earth Science Education
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• v.10 no.3
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• pp.308-322
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• 2017

It is the purpose of the study to investigate how high school students understand the concept of carbon cycle according to their spatial perception ability. For this, a total of 30 male students and 33 female students, who belong to the science course of the 2nd grade at a general co-education high school located in a megalopolis of Korea and have finished the class of Earth Science I in the first semester, took part in the spatial perception ability test, and four male students and four female students were selected as members of two groups : one group of higher spatial perception ability and the other group of lower spatial perception ability, and they agreed to participate in the study and have got the test of the carbon cycle concept. The results are as followings. It was found that the students who had higher spatial perception ability recorded more scores in the carbon cycle concept, state change concept, and process concept at the factor of word association and the carbon cycle concept, state change and process concept at the factor of drawing than those who had lower spatial perception ability. Connecting link used in the systemic viewpoint was disclosed like this in the factor of causal map of those who had higher spatial perception ability : one student 2 and another one student 1 and the other two students 0 : and in the factor of drawing three students 1 and the other 0 ; But nothing was found in the factors of causal map and drawing of those who had lower spatial perception ability. In addition, it was also found that those students who had higher spatial perception ability, when compared with those students who had lower spatial perception ability, have understood the fact that carbon moves through the interaction of the earth system's lower parts; Three students, who showed higher spatial perception ability, had a low level of systemic thinking concept, and one student who had higher spatial perception ability and four students who had lower spatial perception ability did not have a systemic thinking concept.