• Journal of Preventive Medicine and Public Health
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• v.35 no.1
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• pp.76-82
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• 2002

Objective : To investigate the relationships of occupational class, educational level and deprivation with mortality in Korea Methods : This study used existing South Korean national data on occupation, educational level, and deprivation and death. Mortality was investigated using registered death data from 1993 to 1997 obtained from the Korean National Statistics Office (NSO) with denominators drawn from the 1995 Census. Statistical analysis consisted of poisson regression modeling and multilevel analysis. Results : The lower occupational class (manual workers) group had a higher mortality rate than the higher occupational class (non-manual workers) group Educational level, and deprivation were both inversely related withand mortality. Occupation was strongly associated with education. Area-based deprivation indicators and individual indices for social class made an independent contribution to the mortality risk. Conclusions : The findings of this study suggests that the relationships of occupational class, educational level and deprivation with mortality appears to be stronger in Korea than in European countries.

• East Asian mathematical journal
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• v.37 no.1
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• pp.87-95
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• 2021

Let K be an imaginary quadratic field with ��K its ring of integers. For a positive integer N, let K(N) be the ray class field of K modulo N��K, and let ��N be the field of meromorphic modular functions of level N whose Fourier coefficients lie in the Nth cyclotomic field. For each h ∈ ��N, we construct a ray class invariant as its special value in terms of the extended form class group, and show that the invariant satisfies the natural transformation formula via the Artin map in the sense of Siegel and Stark. Finally, we establish an isomorphism between the extended form class group and Gal(K(N)/K) without any restriction on K.

• The korean journal of orthodontics
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• v.32 no.4 s.93
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• pp.241-255
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• 2002

This study was performed to evaluate horizontal and vertical characteristics according to lateral cephalometry of adult Korean skeletal Class II patients using a selected horizontal and vortical reference planes of Koreans. 60 males and 60 females consisting of freshman of Yonsei University from 1996 to 1997 and patients with history of orthognatic surgery at the Dental Hospital of Yonsei University with a skeletal Class II profile were chosen and compared with 70 males and 70 females with normal occlusion. The skeletal Class R group had the following conditions : 1. Profile composed of a retrognathic mandible or protrusive maxilla; 2. Class II molar and canine key; 3. ANB-greater than $4^{\circ}; 4$. Wits appraisal-greater than 1.0mm; Cephalometric analysis consisted of 22 skeletal, 25 soft tissue, 12 dental measurements. The results were as follows. 1. There was no considerable vortical measurement difference between the skeletal Class II malocclusion group and the normal occlusion group in skeletal analysis. But, some variations were found between the two groups in soft tissue analysis. 2. Mandibular length of the skeletal Class II malocclusion group was smaller than that of the normal occlusion group. Mandible was more posteriorly positioned in the Class II malocclusion group than in the normal occlusion group. 3. The length and antero-posterior position of the maxilla were not different between the Class II malocclusion and the normal occlusion group. 4. The antero-posterior position of the nose, upper lip and maxillary soft tissue, and nasolabial angle were not different between the two groups. 5. Mandibular soft tissue of the Class H malocclusion group was more posteriorly positioned than that of the normal. 6. The vertical measurements of the incisors(U1-HP, L1-HP) were bigger in the Class II malocclusion group than in the normal, but those of the molars(U6-HP, U6-MP) showed no significant difference between the two groups. 7 Classifying the skeletal Class II malocclusion group according to the antero-posterior position of both jaws, normally positioned maxilla and retruded mandible was 43.3%, both normally positioned maxilla and mandible 28.3%, both retruded maxilla and mandible 20.0%..

• Bulletin of the Korean Mathematical Society
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• v.45 no.3
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• pp.457-466
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• 2008

Let R be a right near-ring. An R-group of type-5/2 which is a natural generalization of an irreducible (ring) module is introduced in near-rings. An R-group of type-5/2 is an R-group of type-2 and an R-group of type-3 is an R-group of type-5/2. Using it $J_{5/2}$, the Jacobson radical of type-5/2, is introduced in near-rings and it is observed that $J_2(R){\subseteq}J_{5/2}(R){\subseteq}J_3(R)$. It is shown that $J_{5/2}$ is an ideal-hereditary Kurosh-Amitsur radical (KA-radical) in the class of all zero-symmetric near-rings. But $J_{5/2}$ is not a KA-radical in the class of all near-rings. By introducing an R-group of type-(5/2)(0) it is shown that $J_{(5/2)(0)}$, the corresponding Jacobson radical of type-(5/2)(0), is a KA-radical in the class of all near-rings which extends the radical $J_{5/2}$ of zero-symmetric near-rings to the class of all near-rings.

• Restorative Dentistry and Endodontics
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• v.23 no.1
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• pp.304-315
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• 1998

The purpose of this study was to evaluate the microleakage of light cured glass ionomer restorative materials in class 5 cavities. In this in vitro study, class 5 cavities were prepared on buccal and lingual surfaces of forty extracted human premolars and molars on cementum margin. These specimen were randomly divided into four groups of 10 each : Group 1 was Fugi II (control), Group 2 was Fugi II LC, Group 3 was Vitremer, and Group 4 was Dyract. Group 2 was also divided once more into 2 groups of 5 each : Group 2-1 was pretreated with dentin conditioner and Group 2-2 was not. All teeth were restored according to the manufacturer's instructions. After 500 thermocycling between $5^{\circ}C$ and $55^{\circ}C$, the 40 teeth were placed in 2 % Methylene blue dye for 24hr, then rinsed with tab water. The specimen were embedded in clear resin, then sectioned buccolingually through the center of restoration with a low speed diamond saw. The dye penetration on each of the specimen were then observed with a stereomicroscope at 20. The results of the study were statistically analyzed using the Student-Newman-Keuls Methods and the Mann-Whitney Rank Sum Test. Tooth restorative interfaces were evaluated using SEM analysis. Results were as follows, 1. Compared to conventional glass ionomer restoratioqs, all light cured glass ionomer restorations were fairly resistant to microleakage (P<0.05). 2. Groups 3 (Vitremer) and Group 4 (Dyract) were found to be the most resistant, Group 2 (Fugi II LC) fairly resistant, and Group 1 (Fugi II) least resistant to microleakage(P<0.05). 3. No significant differences were found between Group 2-1 and Group 2-2 (P>0.08). 4. With the backscattered SEM analysis, the degrees to which tight bonding occurred were also observed in all the groups except for Group 1. Group 4 showed the highest degree of tight bonding than any other materials used in this study.

• Journal of the Korean School Mathematics Society
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• v.3 no.1
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• pp.177-188
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• 2000

Mathematics is extreme the differences of the scholarly attainments in comparison with other subjects at a middle school. Specially, the students at islands and places leave much to be desired the scholarly attainments standards of mathematics. Therefore, every school takes movement class according to level these days. And the small schools put in effect the cooperation of group work through the small groups. These classes are effective at the scholarly attainments extension to some degree, but each student is extreme the differences of scholarly attainments. On this, the small school was the subject of study at the present research and put in effect the cooperation of group work through the small groups. The students were divided in three groups; the top class, average, the low class, And they were offered the fitting textbooks matching the cooperation of group work and the opportunities of discovery learning fitting an individual ability and standard. Consequently, some educational materials were made, for example, question papers, commonness learning materials, choice learning materials. These materials were put in effect to the students to be able to succeed discovery learning. With this, the students were investigated an interest of mathematics and the influence giving at the studies attainment. And the students were put in effect the cooperation of group work through the small groups to improve uniformity and sturdiness of the mathematical education. The conclusion at the present research is as follows. 1) When the students put in effect the cooperation of group work through the small groups, the scholarly attainments of mathematics totally didn't display useful changes as improvement. However, the students of average and the low class gradually seemed to improve the scholarly attainments of mathematics as the help of the top class positively. 2) An individual and cooperation learning in the method of the cooperation of group work through the small groups displayed many changes at the learning attitude of the students by means of discovery learning thanks to the learning heads. 3) When the investigator put in effect the cooperation of group work through rather the small groups than the large groups, the numbers of the students experiencing interest about mathematics increased in 26% and this learning method should continue to progress.

• Journal of Environmental Science International
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• v.20 no.12
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• pp.1625-1634
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• 2011

The aim of this study is to clarify what influence has on elementary school children's environmental awareness in time of teaching environmental problems from an animistic viewpoint and from non-animistic viewpoint. For this purpose, this study carried out its research targeting 126 students in fourth grade at M elementary school located in U Metropolitan City. This study suggested the environmental problems by re-edifying the already suggested environmental problems from an animistic viewpoint to 62 students for two classes which were classified as an experimental group after sampling 10 cases of the representative environmental problems that might derive from the earth system, and conducted the class on 10 main topics relevant to the problematic situation of environment with an animistic viewpoint excluded targeting the remaining 64 students forming a comparison group. The results of this study were as follows: First, there appeared an ex-ante ex-post statistically significant difference in the awareness of environmental problems from the experimental group which received an environmental class from an animistic viewpoint. However, there didn't appear a statistically significant difference from the comparison group. This study interprets this result to mean that elementary students' awareness of environmental problems increase because they think about the environmental problems by associating them with a problem of life when the students receive the environmental class from an animistic viewpoint. Second, there appeared an ex-ante ex-post statistically significant difference in the awareness of environmental problems from the experimental group which received an environmental class from an animistic viewpoint. However, there didn't appear a statistically significant difference from the comparison group. Regarding this aspect, this study believes that the experimental group shows much higher willingness to environmental act in comparison with the comparison group because elementary school students think of inanimate objects as living things.

• Journal of the Korean Society of Earth Science Education
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• v.6 no.1
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• pp.60-68
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• 2013

The aim of the study is determined to find out how elementary science localization teaching strategy would influence environmental perception of students. In order to fulfill the research purpose, a total of 51 fifth graders from two classes in M Elementary School in U City were divided into a 26 of experimental group and a 25 of comparative group. The study was carried out from September to November of 2012. For the experimental group, an elementary science localization classes were conducted while for the comparative group, a general science classes were performed. The results of the research are presented as follows. First, it was learned that the experimental group with the elementary science localization class would have a significantly and statistically high environmental sensitivity comparing to that of the comparative group. That proves the elementary science localization class's being efficient at improving the students' environmental sensitivity. Second, the experimental group with the elementary science localization class turned out to have a significantly and statistically strong will to protect the environment than the comparative group would do. Such finding says that the elementary science localization class is helpful to enhance the students' will to preserve the environment. In conclusion, the study came to understand that the elementary science localization teaching strategy can improve the environmental perceptions of the students for such elementary science localization class would efficiently encourage environmental interest of the students.

• The korean journal of orthodontics
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• v.27 no.5 s.64
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• pp.801-813
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• 1997

A comparative study was made on the chewing movements of normal occlusion and skeletal class m malocclusion. Thirty normal occlusion subjects and twenty skeletal class III malocclusion patients were given chewing gums for the study : using BioPAK system, the chewing movement on the frontal plane was recorded and analyzed. With a typical chewing path chosen representing each subject, chewing width, opening distance, opening and closing angles, maximum opening and closing velocities were observed. Seven characteristic patterns were classified based on the types of chewing paths. The followings are the results : 1. Compared with the normal occlusion group, the skeletal class III malocclusion group showed more varied and vertical chewing patterns. 2. In comparision of chewing widths, skeletal class m malocclusion group showed narrower path than the normal occlusion group(p<0.01). 3. In opening distance, skeletal class III malocclusion group appeared shorter than the normal occlusion group without statistical significance(p>0.05). 4. In opening and closing angles, skeletal class III malocclusion group showed more acute angles than the normal occlusion group(p<0.01). 5. In maximum opening and closing velocities, skeletal class III malocclusion group was slower than the normal occlusion group but with no statistical significance(P>0.05). 6. In the classification of chewing movement pattern, the normal occlusion group had Type II as the highest rate at 73.4% ; in skeletal class III malocclusion group, the highest rate was Type III at 35.0%, followed by Type II at 30.0% 7. In the classification of chewing movement pattern, Type IV(chopping type)of skeletal class III malocclusion group showed a higher rate with 25.0% over 3.3% of normal occlusion group.

• Journal of the Korean Chemical Society
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• v.50 no.6
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• pp.506-514
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• 2006

purpose of this work was to study the applied effects of out-of-class Chemical Experience Learning (CEL) Programs on scientific process skills and science-related attitude for middle school students. The out-of-class CEL Programs which were developed to make the funny out-of-class chemistry and the exciting science class', included the nature-friendly chemical experiments suitable for natural environment and composed of real life-centered experiences. The out-of-class CEL programs were applied to natural environment through all-day improvement activity. The science club students in D middle school in Busan were selected as the objects of the study consisting of one experiment group and one control group. The out-of-class CEL programs were applied to the experiment group and traditional class method was applied to the control group. The change of scientific process skills and science-related attitudes between two groups were compared and analyzed. And students reaction on the out-of-class CEL programs was investigated. As a result, out-of-class nature-friendly chemical experiments were improved scientific process skills and science-related attitudes of middle school students. Also, more than 70% of students in the experimental group gave positive feedbacks to the out-of-class CEL programs and increased attention, interest, and degree of self-participation in science.