• 대한수학회지
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• 제37권3호
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• pp.491-502
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• 2000

The disjoint union of mapping class groups g,1 gives us a braided monoidal category so that it gives rise to a double loop space structure. We show that there exists a natural twist in this category, so it gives us a ribbon category. We show that there exists a natural twist in this category, so it gives us a ribbon category. We explicitly express this structure by showing how the twist acts on the fundamental group of the surface Sg,l. We also make an explicit description of this structure in terms of the standard Dehn twists, as well as in terms of Wajnryb's Dehn twists. We show that the inverse of the twist g for the genus g equals the Dehn twist along the fixed boundary of the surface Sg,l.

• 영어어문교육
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• 제15권2호
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• pp.151-168
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• 2009

The present study investigates the impact of trained peer feedback on the quantity and quality of revisions made by EFL students at a low-intermediate level. Peer review training was carried out in experimental group through four in-class training sessions and four peer dyad-instructor conferences after class. Students' $1^{st}$ drafts with written peer feedback and revised drafts prior to and post training were collected and analyzed. Results reveal that after training the students produced more revisions in response to their peer comments (96% of total revisions) and those revisions were counted as enhanced in quality (93% of peer-triggered revisions). In contrast, the results of paired t-test within control group indicate that there was no significant difference between two data collected from week 3 and week 16 (t = -.57, df =19, p = .577 at p < .05). The findings suggest that training as an ongoing process of teacher intervention contributes to effectiveness of the peer feedback activity. The study provides pedagogical implications for how to structure and implement peer review training for the sake of its direct strength in an EFL writing class.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• 제29권2호
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• pp.54-61
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• 2018

Objectives: This study was conducted to investigate the effectiveness of a class-based school violence prevention program for elementary school student. Methods: 29 students were assigned to the school violence prevention program of 8 sessions, 28 students have been assigned to the control group. We assessed participants at baseline and post-intervention, through their self-report questionnaires such as Children's Depression Inventory (CDI), Strengths and Difficulties Questionnaire and school violence experience, awareness about school violence, and coping ability to school violence. We compared the baseline and post-intervention result of each group and compared the post-test scores between the intervention group and the control group. Results: Comparing the intervention group and the control group, the post-intervention CDI total score and the awareness about school violence showed significant improvement in the intervention group. When compared according to gender, male students' perception of school violence was improved, and female students showed significant differences in CDI scores. Conclusion: The CDI total scores and the perception of school violence were improved in the intervention group compared to the control group. And there are differential pattern of intervention effects according to gender. These findings have important implications to develop effective violence prevention programs.

• Restorative Dentistry and Endodontics
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• 제10권1호
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• pp.161-168
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• 1984

The purpose of this study was to examine the effect of heat generated by rotating bur on the dental hard tissue in vitro. Freshly extracted molar teeth with normal appearance from early 20's male were collected and experimental teeth were divided into 4 groups and the teeth in each group were prepared class I cavity with different clinical procedures as follows. The four methods were. I. 20,000rpm without coolant II. 20,000rpm with coolant III. 500,000rpm without coolant IV. 500,000rpm with coolant Five teeth were reserved intact as a control group. These teeth were longitudinally split into two parts by means of chisel after class I cavity preparation. In a control group 5 parts were boiled in water for 20 minutes and the other 5 specimens were not boiled. All specimens were immersed in 2% methylene blue dye solution and the image of dye penetration was examined and photographed under stereomicroscope. Followings were the results obtained through the study. 1. In control group, dye penetration of the unboiled specimens was increased than with the boiled group. 2. The specimens prepared cavity without coolant showed decreased dye penetration than with the coolant group. 3. 20,000rpm without coolant group showed the least dye penetration. 4. 500,000rpm with coolant group showed similar level of dye penetration to the unboiled specimens from the control group.

• 가정과삶의질연구
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• 제16권1호
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• pp.63-80
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• 1998

The purpose of this study is to analyze the effects of unstructured and spontaeous role-playing in pro-social behavior of a child. The experimental group in this study is 7 children who go to after-school class in J. social welfare facility and the controlled group is 7 children in composition class., While the experimental group did role-playing with each other the control group did not have any treatment, In order to find out effects of an experiment pre-test first post-test and second post-test were done. The results can be concluded as following. First in pre-test the degree of behavior resulted the same in experimental group and in controlled group. However in the first post-test the pro-social behavior of the experimental group with role-playing showed an improve than that of the controlled group. Therefore it can be emphasized once more that the role-playing improves pro-social behavior of a child. Second in the second post-test done 2 moth after the role-playing it was found that the pro-social behavior of experimental group keep the improved points as in the first post-test Therefore it can be concluded that the effect of role-playing on pro-social behavior of a child is continuous.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제38권1호
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• pp.9-13
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• 2012

Introduction: To evaluate the 3-dimensional changes in the pharyngeal airway of skeletal class III patients after bimaxillary surgery. Materials and Methods: The study sample consisted of 18 Korean patients that had undergone maxillary setback or posterosuperior movement and mandibular bilateral sagittal split osteotomy setback surgery due to skeletal class III malocclusion (8 males, 10 females; mean age of 28.7). Cone beam computed tomography was taken 1 month before and 6 months after orthognathic surgery. Preoperative and postoperative volumes of the nasopharyngeal, oropharyngeal, and laryngopharyngeal airways and minimum axial areas of the oropharyngeal and laryngopharyngeal spaces were measured. Moreover, the pharyngeal airway volume of the patient group that had received genioplasty advancement was compared with the other group that had not. Results: The nasopharyngeal and laryngopharyngeal spaces did not show significant differences before or after surgery. However, the oropharyngeal space volume and total volume of pharyngeal airway decreased significantly (P<0.05). The minimum axial area of the oropharynx also decreased significantly. Conclusion: The results indicate that bimaxillary surgery decreased the volume and the minimum axial area of the oropharyngeal space. Advanced genioplasty did not seem to have a significant effect on the volumes of the oropharyngeal and laryngopharyngeal spaces.

• 호남수학학술지
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• 제26권3호
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• pp.247-256
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• 2004

Buchmann and Williams[1] proposed a key exchange system making use of the properties of the maximal order of an imaginary quadratic field. $H{\ddot{u}}hnlein$ et al. [6,7] also introduced a cryptosystem with trapdoor decryption in the class group of the non-maximal imaginary quadratic order with prime conductor q. Their common techniques are based on the properties of the invertible ideals of the maximal or non-maximal orders respectively. Kim and Moon [8], however, proposed a key-exchange system and a public-key encryption scheme, based on the class semigroups of imaginary quadratic non-maximal orders. In Kim and Moon[8]'s cryptosystem, a non-invertible ideal is chosen as a generator of key-exchange ststem and their secret key is some characteristic value of the ideal on the basis of Zanardo et al.[9]'s quantity for ideal equivalence. In this paper we propose the methods for finding the non-invertible ideals corresponding to non-primitive quadratic forms and clarify the structure of the class semigroup of non-maximal order as finitely disjoint union of groups with some quantities correctly. And then we correct the misconceptions of Zanardo et al.[9] and analyze Kim and Moon[8]'s cryptosystem.

• 대한치과교정학회지
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• 제26권5호
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• pp.509-522
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• 1996

하악골 성장양상이 진단과 치료, 치료후 예후에 특히 중요한 III급 부정교합자에 있어 그 성장양상을 예측하는데 도움을 주고자 사춘기 전으로 생각되는 남자 10-12세군(G1군)과 악골성장이 거의 끝난 것으로 생각되는 성인으로 남자 20세 이상군(G2군)에 대하여 각각 이부비율에 따라 다시 3군으로 분류하고 이부형태와 두개안면형태의 연관성을 연구 한 결과 다음과 같은 결론을 얻었다. 1. 평균 이부비율에 있어 G2군이 G1군에 비해 통계학적으로 유의성 있게 크게 나타났다(p<0.05). 2. G1군과 G2군 모두 이부비율과 두개저 계측항목과는 상관성이 없었다(P>0.05). 3. 상하악골의 수평적 관계 계측항목에서 G1군과 G2군 모두 이부비율과 상악골 계측항목과는 상관성이 없었다(p>0.05). 또한 G1군과 G2군 모두 L, A, S군간 하악의 전후적 위치는 뚜렷한 차이가 없고, 단지 G1군의 Y-axis angle에서 L군이 S군에 비해 크고 G2군은 Pog to Na perp.에서 S군이 L군에 비해 통계학적으로 유의성 있게 크게 나타났다(p<0.05). 4. 하악골의 형태 계측항목에서 gonial angle은 G1군과 G2군 모두 이부비율이 클 수록 수치적으로 증가하나 통계학적인 유의성은 없었다(p>0.05). Lower genial angle과 chin angle은 G1군에서 L군과 A군이 S군보다 통계학적으로 유의성 있게 크게 나타났다(p<0.05). 5. 안면의 수직적 관계 계측항목에서 G1군은 L군이 S군에 비해 전안면고경, 전하안면고경이 통계학적으로 유의성 있게 크며(p<0.05) 하악골이 하방성장한 경향을 보여주었다. 6. 치아의 위치 및 경사도 계측항목에서 G1군은 하방성장을 많이 한 L군이 S군에 비해 상하악 치아들이 정출되어 있는 경향을 보여주었지만 G2군은 단지 하악치아 만이 그러한 경향이 있었다. 7. 이부비율과 다른 계측항목과의 상관분석에서 G1군은 chin angle, PP/MP angle, ANS-Me등 많은 계측항목에서 G2군은 단지 MP-LIT와 MP-LMMC에서 통계학적으로 유의성 있는 상관성을 보였다(p<0.05, p<0.01). 이상을 종합하면 어린 남자군인 G1군에서는 이부비율이 큰 군(L군)과 작은 군(S군)사이에 수평적 골격관계는 차이가 없으나 수직적 골격관계는 L군이 S군에 비해 하악골이 하방으로 많이 성장한 경향을 보여주었다. 하지만 성인 남자군인 G2군에서는 이부비율에 따른 안면골격의 뚜렷한 형태적 차이를 보여주지 않았다.

• 디지털콘텐츠학회 논문지
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• 제19권6호
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• pp.1123-1129
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• 2018

본 연구의 목적은 보육교사의 모바일 알림장 사용경험에 대하여 알아보는데 있다. 연구대상은 서울 경기지역에 소재한 모바일 알림장을 사용하고 있는 보육교사 7명으로, 심층면담을 통해 자료를 수집하였다. 연구 결과 첫 째, 보육교사의 [모바일 알림장 사용경험 중 긍정적인 측면]에 관한 주제군은 <교사와 부모와의 신뢰감 향상>, <즉각적인 일처리의 효율화>로 주제가 분류되었다. 둘 째 보육교사의 [모바일 알림장 사용경험 중 부정적인 측면]에 관한 주제군은 <업무량 증가에 대한 어려움>, <모바일 알림장 기능의 다양화에 대한 아쉬움>으로 주제가 분류되었다. 본 연구는 향후 부모와 교사간의 신뢰할 수 있는 의사소통 자료를 제공하고, 모바일 알림장을 보다 효과적으로 활용할 수 있도록 기초자료를 제시하는데 의의가 있다.

• 대한수학교육학회지:학교수학
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• 제16권3호
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• pp.633-657
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• 2014

본 연구는 상황학습 기반 수업이 초등학교 6학년 학생들의 수학학습에 미치는 영향을 검증하고자 하는데 주요한 목적이 있다. 이를 위해서 본 연구는 실험집단에는 상황학습 기반 수업을 적용하였으며 비교집단에는 교과서 중심의 일반적 수학 수업을 적용하였다. 본 연구는 두 집단의 수학 학업성취도와 수학적 태도에 어떠한 차이가 있는지를 알아보았으며, 또한 수업 상황에 대한 질적 분석을 통해서 수업에서의 교사의 역할과 학생들의 수업 참여 방식을 살펴봄으로써 상황학습 기반 수업의 교육적 효과를 검증하였다. 그 결과, 첫째, 상황학습 기반 수업은 학생들의 수학 학업성취도와 수학적 태도에 긍정적인 영향을 미침을 알 수 있었다. 둘째, 상황학습 기반 수업에서 교사는 학습 촉진자의 역할을 하는 것으로 나타났다. 셋째, 상황학습 기반 수업에서 학생들은 수업 상황 중에 서로에게 도움의 대상, 배움의 대상이 됨으로써 문제해결을 위한 협력적 태도와 적극적인 노력을 보였다.