• 대한수학회지
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• 제50권4호
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• pp.865-877
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• 2013

The disjoint union of mapping class groups of surfaces forms a braided monoidal category $\mathcal{M}$, as the disjoint union of the braid groups $\mathcal{B}$ does. We give a concrete and geometric meaning of the braidings ${\beta}_{r,s}$ in $\mathcal{M}$. Moreover, we find a set of elements in the mapping class groups which correspond to the standard generators of the braid groups. Using this, we can define an obvious map ${\phi}\;:\;B_g{\rightarrow}{\Gamma}_{g,1}$. We show that this map ${\phi}$ is injective and nongeometric in the sense of Wajnryb. Since this map extends to a braided monoidal functor ${\Phi}\;:\;\mathcal{B}{\rightarrow}\mathcal{M}$, the integral homology homomorphism induced by ${\phi}$ is trivial in the stable range.

• 대한수학회보
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• 제53권4호
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• pp.1033-1041
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• 2016

We show that, for any non-zero integers ${\lambda}$, ${\mu}$, ${\nu}$, ${\xi}$, class-preserving automorphisms of the group $$G({\lambda},{\mu},{\nu},{\xi})={\langle}a,b,t:b^{-1}a^{\lambda}b=a^{\mu},t^{-1}a^{\nu}t=b^{\xi}{\rangle}$$ are all inner. Hence, by using Grossman's result, the outer automorphism group of $G({\lambda},{\pm}{\lambda},{\nu},{\xi})$ is residually finite.

• 대한가정학회지
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• 제43권4호
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• pp.49-63
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• 2005

The Purposes of this study were to segment Chinese consumers by clothing Purchase motive, and then to analyze and compare the clothing purchasing behavior among the segmented groups. The subjects were 655 career women of middle and high class in their 20's and 30's living in Benjing, Shanghai, Shenzhen, and Changchun. A total of 655 questionnaires were analyzed by using frequency, mean, factor analysis, ANOVA, Duncan's multiple range test, cluster analysis, and X^2 _ test. The results were as follows: 1. Chinese consumers were segmented into clothing high-involvement group, fashion pursuing group, practicality pursuing group, and characterless group. 2. The clothing purchase behavior variables such as purchasing motive, using informants, clothing selection standards, store selection standards, purchasing place, satisfaction after purchasing clothes, price of purchase, shopping time, shopping companion, and paying method were significantly different among the 4 segmented groups. 3. The demographic variables such as a city, marriage, total monthly income, and average monthly expenditure on clothing were significantly different among the 4 segmented groups.

• Restorative Dentistry and Endodontics
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• 제15권1호
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• pp.107-119
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• 1990

The purpose of this study was to evaluate the marginal adaptability of the amalgam restorations in applying the cavity varnish (Copalite$^{(R)}$) and dentin bonding agent (Scotchbond 2$^{(R)}$) under the scanning electron microscope. For this study, eighteen sound extracted human molars were selected. Class I cavities in 12 teeth and class V cavities in 6 teeth were prepared using an air turbine with No. 701 tungsten carbide bur and finished using a low speed handpiece with No. 557 fissure bur. The prepared specimens were then divided into three groups including 4 class I cavities and 2 class V cavities in each group and restored as follows ; Group I. All the prepared cavities were restored with amalgam only (Control). Group II. Two layers of Copalite$^{(R)}$ cavity varnish were applied to the cavities with a gentle stream of air after each application and cavities were restored with amalgam. Group III. The enamel cavity margins were etched with 37% phosphoric acid gel for 60 sec., rinsed for 30 sec. and dried. One layer of visible lightcured Scotchbond Dental Adhesive$^{(R)}$ was applied and immediately cured for 20 seconds with visible light-cure unit and cavities were restored with amalgam. All the specimens were cut at the neck of the teeth and the occlusal halves of specimens were sectioned buccolingually in the longitudinal axis centering the amalgam restorations, using the disk. The cut specimens were ground with sandpapers (400, 600, 800, 1000 grit), and cleaned for 5 minutes in the ultrasonic cleaner (Brason Co. U.S.A.). In the cut surfaces, the amalgam - tooth interfaces were examined under the scanning electron microscope (JSM, 35C type, JEOL). The obtained results were as follows ; 1. The amalgam-tooth interfaces were reduced more significantly in the Copalite$^{(R)}$ and Scotchbond 2$^{(R)}$ application group than in the control group. 2. In the class I cavities, the Scotchbond 2$^{(R)}$ application group showed the findings similar to the Copalite$^{(R)}$ application group in the cavity floor, and the marginal adaptability was better in the side wall than in the cavity floor. 3. In the class I cavities, the Scotchbond 2$^{(R)}$ application group showed better marginal adaptability in the occlusal margin than in the gingival margin. 4. The marginal adaptability was in the order of the Scothbond 2$^{(R)}$ application group, the Copalite$^{(R)}$ application group and the control group.

• 대한치과교정학회지
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• 제26권1호
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• pp.65-82
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• 1996

본 연구는 II급 및 III급 부정교합자를 대상으로 activator사용에 따른 각 근육의 적응 및 변화양상을 알아보고자 시행되었다. 본 연구의 대상은 성장 발육기에 있는 아동중 II급 부정교합자 15명과 III급 부정교합자 17명으로 기능적 요인을 갖고있는 자로 선정하였고, 연구방법은 전측두근(T.A.), 교근(M.M.), 후측두근(T.P.), 악이복근 전복(D.A.)의 활성도를 알아보고자 $Biopak^{TM}$ program 과 쌍극표면전극을 이용하여 activator 치료 시작시기와 사용후 6-12개월 사이의 두차례에 걸쳐 안정위, 연하시, clenching등 세가지 조건에서 근활성도를 측정하여 비교해본 결과 다음과 같은 결론을 얻었다. II급 및 III급 부정교합자와 정상교합자의 근활성도를 비교한 결과 안정위시와 연하시 유의한 차이를 보이지 않았으나 clenching시 교근과 후측두근에서는 차이를 나타내었다. 치료전 근활성도가 정상보다 작은 군은 유의성 있는 증가를, 큰 군은 유의성 있는 감소를 보이는 등 대부분의 근육이 일정한 경향을 나타내었고, 이러한 경향은 III급 부정교합군에서 전측두근(연하시), 후측두근(clenching시), 악이복근 전복(연하시, clenching시)을 제외하고 모두에서 보였으며 II급 부정교합군에서는 전측두근(연하시), 교근(안정위, 연하시), 후측두근(clenching시)에서만 관찰되었다. 그러나 이러한 경향은 clenching시에서 감소되었다. II급 부정교합군과 III급 부정교합군과의 근활성도 비교에서 안정위시는 III급 부정교합군의 근활성도 증가율이 II급 부정교합군보다 우세했고, 연하시에는 교근을 제외하고 II급 부정교합군이, clenching시에는 역시 II급 부정교합군이 악이복근 전복을 제외하고 우세하게 나타났다.

• Journal of Periodontal and Implant Science
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• 제27권4호
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• pp.845-866
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• 1997

Several experimental studies showed that the application of small amounts of electric current to bone stimulated osteogenesis at the site of the cathode and suggests that the application of electrical currents to periodontal defects could promote bone and cementum formation. The purpose of this study was to determine the effect of direct microcurrent to the periodontal regeneration of class III furcation defects in dogs. Class III furcation defects were surgically created on the third and the fourth premolars bilaterally in the mandibles of nine mongrel dogs. Experimental periodontitis were induced by placing small cotton pellets into the created defects for 3 weeks. The experimental sites were divided into three groups according to the treatment modalities: Group I-surgical debridement only; Group II-allogenic demineralized freeze dried bone grafting; Group III-allogenic demineralized freeze dried bone grafting and electrical stimulation. For fluorescence microscopic evaluation, calcein, oxytetracycline HCI and alizarin red were injected 2, 4 and 8 weeksfS days prior to sacrifice) after surgery. The animals were sacrificed in the 1st, 2nd, 4th and 8th week after periodontal surgery and the decalcified and undecalcified specimens were prepared for histological and histometrical examination. After the first and the second weeks, gingival recession was more severe in group I than groups II and III. After the fourth and the eighth weeks, there was no difference in the width of junctional epithelium and connective tissue attachment among the three groups, but the width of connective tissue attachment increased in group II at the eighth week, compared to the fourth week. The amount of bone repair in new attachment was significantly greater in group III, compared to groups I and II. New attachment formation was significantly greater in group III, compared to groups I and group II. These results suggest that electrical stimulation using microcurrent generator could be a useful tool for periodontal regenerative therapy in class III furcation defect.

• 대한가정학회지
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• 제12권2호
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• pp.609-619
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• 1974

The purpose of this study is to survey Korean mother's child-rearing methods and to see what influence each layed on children's school achievement. To obtain data, a questionaire was given to 607 boys and girls, who were selected from both public and private middle schools in Seoul. The student were consisted of two distinct groups, namely superior and inferior. Five top students from each class were categorized as the superior group and five bottom ones from each class were categorized as the inferior group. The questionaire was consisted of 7 items, namely, the needing method, feeding period, weaning time, mothers general attitudes about crying, sleeping arrangement and whether mothers workers or not. Summary of this study is as follows ; 1. As far as babies were breast-fed, there was no significant between the superior group and the interior group no matter what feeding period and weaning time were. 2. When the babies were fed by milk or both by milk and breast, the most favorable weaning time for intellectual development seemed to be between 6 and 9 months after birth. 3. The mother's general attitudes to babies crying and the sleeping arrangement have definite influence on the children's school achievement. It was shown that if mothers hugged babies as soon as they cried the babies tended to be superior, but the mothers of inferior group had tendency to let alone, until the babies stopped crying or hug after finishing their urgent works. Then the superior group was allowed to sleep alone in his own bed in the mother's room. On the contrary, the inferior group was kept in their mother bed or that of other family's without being given his own bed. 4. Whether mother had a job or not did not had any influence on children's school achievement. 5. Korean mothers have tendency to hug their babies as soon as when they find them cry and feed them with breast milk. The study also shows that the mothers rearing attitudes has certain influencial effect upon the children's school achievement.

• 한국주거학회논문집
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• 제8권1호
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• pp.1-12
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• 1997

The purpose of this research is to identify user needs for community space design, especially shared space. and compare them according to social class. Since the shared space concept is new, it will be difficult for residents to familiarize themselves with the new idea. This study used a Small Croup Workshop Panel Method instead of the conventional survey method for this reason The subjects were 6 Panel groups of S people per each group. Bach of the panels included 3consecutive workshops. The results can be summarised as follows. All the residents wanted various kinds of shared spaces for everyday living and leisure activity While there were generally great similarity regardless of resident's sub characteristics, some founed distintively dissimilar. The residents of 20s pyung apartment wanted day-care center, multi Purpose room for meeting and family events, library, study room, sports facilities, and cultural center in order. The shared spaces that residents of 30s pyung apartment wanted were library. study room. common dining, sports facilities. and cultural center in order. The residents of 50s pyung apartment wanted library, study room. multi purpose room, common storage, sports facilities. and cultural center in order. These findings imply some diverse plans instead of uniform ones are to be deliberately considered, This results can be usefully applied to develop new collective housing for different social class residents.

• Restorative Dentistry and Endodontics
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• 제42권1호
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• pp.48-53
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• 2017

Objectives: The aim of this study was to investigate the ability of the fluorescence-aided caries excavation (FACE) device to detect residual caries by comparing conventional methods in vivo. Materials and Methods: A total of 301 females and 202 males with carious teeth participated in this study. The cavity preparations were done by grade 4 (Group 1, 154 teeth), grade 5 (Group 2, 176 teeth), and postgraduate (Group 3, 173 teeth) students. After caries excavation using a handpiece and hand instruments, the presence of residual caries was evaluated by 2 investigators who were previously calibrated for visual-tactile assessment with and without magnifying glasses and trained in the use of a FACE device. The tooth number, cavity type, and presence or absence of residual caries were recorded. The data were analyzed using the Chi-square test, the Fisher's Exact test, or the McNemar test as appropriate. Kappa statistics was used for calibration. In all tests, the level of significance was set at p = 0.05. Results: Almost half of the cavities prepared were Class II (Class I, 20.9%; Class II, 48.9%; Class III, 20.1%; Class IV, 3.4%; Class V, 6.8%). Higher numbers of cavities left with caries were observed in Groups 1 and 2 than in Group 3 for all examination methods. Significant differences were found between visual inspection with or without magnifying glasses and inspection with a FACE device for all groups (p < 0.001). More residual caries were detected through inspection with a FACE device (46.5%) than through either visual inspection (31.8%) or inspection with a magnifying glass (37.6%). Conclusions: Within the limitations of this study, the FACE device may be an effective method for the detection of residual caries.

• 대한공업교육학회지
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• 제37권1호
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• pp.65-85
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• 2012

이 연구는 '발명 기법과 실제' 단원에서 동료 멘토링 수업이 자아효능감에 미치는 영향을 밝히는 데 그 목적이 있다. 이를 위해 실험 집단과 비교 집단을 선정하여 연구를 실시하였다. 발명 기법과 실제 단원의 5차시에 대한 학습을 실험 집단에게는 동료 멘토링 수업을 진행하였고 비교 집단에는 개별 수업을 적용하였다. 자아효능감에 미치는 영향을 알아보기 위해 자아효능감 검사지를 활용하여 사전 검사와 사후 검사를 실시하였고, 실험 집단과 비교 집단 사이에 의미 있는 차이가 나타날 것인지를 검증하였다. 그 결과를 요약하면 다음과 같다. 첫째, 자아효능감에 대한 검사 결과는 사전 검사에서 두 집단 사이에 유의미한 차이가 나타나지 않았으나 사후 검사에서는 동료 멘토링 수업을 한 실험 집단이 비교 집단보다 통계적으로도 p<.05 수준에서 유의미한 차이를 보였다. 또 집단 내 사전, 사후검사 결과 비교 집단과 실험 집단 모두 통계적으로 p<.05 수준에서 유의미한 차이를 보여 주었으나 자아효능감이 향상된 정도가 비교 집단에 비해 실험 집단이 더 크다고 볼 수 있다. 둘째, 자아효능감의 하위요소별로 살펴보면 활동시작 능력기대, 활동지속 능력기대, 활동수행 능력기대, 경험극복 능력기대의 모든 요소에서 통계적으로 p<.05 수준에서 유의미한 차이가 나타났다. 따라서 동료 멘토링 수업을 적용한 실험 집단이 개별 수업을 적용한 비교 집단보다 자아효능감의 하위요소에 긍정적인 영향을 준다는 것을 확인할 수 있었다. 이러한 결과로 보아 동료 멘토링 수업이 개별 수업보다 자아효능감에 더 긍정적인 변화를 보여주는 교수 학습 방법임을 알 수 있다. 즉, 동료 멘토링 수업이 자아효능감의 향상에 더 효과적이라는 것이 밝혀졌다.