• 대한수학회지
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• 제56권4호
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• pp.869-915
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• 2019

Let H be a Krull monoid with class group G such that every class contains a prime divisor. Then every nonunit $a{\in}H$ can be written as a finite product of irreducible elements. If $a=u_1{\cdot}\;{\ldots}\;{\cdot}u_k$ with irreducibles $u_1,{\ldots},u_k{\in}H$, then k is called the length of the factorization and the set L(a) of all possible k is the set of lengths of a. It is well-known that the system ${\mathcal{L}}(H)=\{{\mathcal{L}}(a){\mid}a{\in}H\}$ depends only on the class group G. We study the inverse question asking whether the system ${\mathcal{L}}(H)$ is characteristic for the class group. Let H' be a further Krull monoid with class group G' such that every class contains a prime divisor and suppose that ${\mathcal{L}}(H)={\mathcal{L}}(H^{\prime})$. We show that, if one of the groups G and G' is finite and has rank at most two, then G and G' are isomorphic (apart from two well-known exceptions).

• 대한치과교정학회지
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• 제50권2호
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• pp.98-107
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• 2020

Objective: The aim of this study was to compare posterior tooth inclinations, occlusal force, and contact area of adults with different sagittal malocclusions. Methods: Transverse skeletal parameters and posterior tooth inclinations were evaluated using cone beam computed tomography images, and occlusal force as well as contact area were assessed using pressure-sensitive films in 124 normodivergent adults. A linear mixed model was used to cluster posterior teeth into maxillary premolar, maxillary molar, mandibular premolar, and mandibular molar groups. Differences among Class I, II, and III groups were compared using an analysis of variance test and least significant difference post-hoc test. Correlations of posterior dental inclinations to occlusal function were analyzed using Pearson's correlation analysis. Results: In male subjects, maxillary premolars and molars had the smallest inclinations in the Class II group while maxillary molars had the greatest inclinations in the Class III group. In female subjects, maxillary molars had the smallest inclinations in the Class II group, while maxillary premolars and molars had the greatest inclinations in the Class III group. Occlusal force and contact area were not significantly different among Class I, II, and III groups. Conclusions: Premolar and molar inclinations showed compensatory inclinations to overcome anteroposterior skeletal discrepancy in the Class II and III groups; however, their occlusal force and contact area were similar to those of Class I group. In subjects with normodivergent facial patterns, although posterior tooth inclinations may vary, difference in occlusal function may be clinically insignificant in adults with Class I, II, and III malocclusions.

• 한국학교수학회논문집
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• 제3권1호
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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.

• 환경영향평가
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• 제22권5호
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• pp.491-511
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• 2013

In this study, three survey areas in Changnyeong, Miryang and Jinju of the confirmed the habitation of nutria and carried out the performance on the plant diet resource. From the habitat trace survey in the nutria habitat, a total of 336 trace points was shown. There were 181 trace points (54%) confirmed from St. 1 as the highest showing, followed by 52 trace points (15.4%) from St. 2, and 103 trace points (30.6)% from St. 3. The vascular plants distributed in the habitat area were a total of 182 taxonomic group with 57 families, 99 genus, 16 hybrids, and 1 race. The vascular plant living types in the habitat area are 1-year plant (Th, Th(w)) for 63class groups (34.6%), hemicryptophyte (H) for 42class groups(23.1%). plants, trees, crop plants were included. As a result of analyzing the overseas research cases on the diet plants of nutria, there are 195 taxonomic groups in a total of 39 families, 126 genus, 183 breeds, and 12 hybrids. In the study areas, feeding the plants was confirmed by the 7 taxonomic groups, aquatic plant, terrestrial From the total of 182 taxonomic groups discovered in the habitat area, 20 class groups, in 3 habitation region, 10 class groups of commonly appearing 49 class groups were shown to be the breed confirmed for diet in existing case studies, and assuming from it basis, the nutria habitating in the survey area is considered to have the supply of diverse diet resource to have flawless habitation. This is implication of having potential breeding possibility.

• East Asian mathematical journal
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• 제26권5호
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• pp.607-614
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• 2010

In this paper, we obtain geodesic formula of a certain class of Pseudoriemmanian 2-step nilpotent groups and show a constancy of represenation matrix of Jacobi oprerators along geodesics in Pseudoriemmanian 2-step nilpotent groups with one dimensional center.

• 한국운동역학회지
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• 제24권3호
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• pp.209-216
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• 2014

The purpose of this study was to explore the effect of 8 weeks after school classes of track sports on students' start motion through kinematic variables. 30 students in D National university of education participated for this study. These students divided into two groups, 17 students for experimental group and 13 students for control group. The two groups participated in general athletic class as common class, and the experimental group participated in after school class additionally. The general class taught track and jump skill for 3 hours a week, and the after school class taught only athletic running skill for 30 minutes a week. Pre and post test assessed to assess students' kinematic changes. Findings indicated that velocity and step rate were increased, and contact time, step length, displacement of center of mass were decreased in the experimental group. In the control group, early velocity, knee/hip angle velocity were increased, and contact time, step length, displacement of center of mass were decreased. In conclusion, the students who only participated in general class, could not maintain athletic skills obtained from the class. However, students who participated in both general and after school class accomplish athletic start skill. This is because Continuous learning effect helped students keep the skill and did not lose the skill. Thus, in order for students to learn specific sport skills, joining after school class with general class together is recommended.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제45권4호
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• pp.215-219
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• 2019

Objectives: Postoperative paresthesia is a common complication after sagittal split osteotomy (SSO). This study aimed to compare paresthesia among different fixation methods one year postoperative. Materials and Methods: This prospective cohort study assessed subjects in four groups: class II with miniplate fixation (Group 1), class II with three-screw fixation (Group 2), class III with miniplate fixation (Group 3), and class III with three-screw fixation (Group 4). Paresthesia was evaluated one year postoperative based on a 0-10 visual analogue scale. Pearson correlation was used to evaluate associations of age and mandibular movement with paresthesia. ANOVA was used to compare paresthesia among groups. Results: A total of 80 subjects were enrolled, with 20 subjects in each of the four groups. The Pearson correlation test demonstrated a significant correlation between mandibular movement and paresthesia (P=0.001). Comparison of paresthesia among the groups showed significant differences among groups 1 and 2, 2 and 3, and 3 and 4 (P<0.05). Conclusion: The three-screw fixation method led to more paresthesia one year postoperative compared with miniplate fixation. In addition, the magnitude of mandibular movement had a positive correlation with paresthesia.

• Korean Journal of Mathematics
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• 제19권4호
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• pp.409-421
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• 2011

We study a natural map from the braid group to the mapping class group which is called Harer map. It is rather new and different from the classical map which was studied in 1980's by F. Cohen, J. Harer et al. We show that this map is homologically trivial for most coefficients by using the fact that this map factors through the symmetric group.

• 대한수학회지
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• 제57권2호
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• pp.383-399
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• 2020

Following Matsumoto's definition of continuous orbit equivalence for one-sided subshifts of finite type, we introduce the notion of orbit equivalence to canonically associated dynamical systems, called the limit dynamical systems, of self-similar groups. We show that the limit dynamical systems of two self-similar groups are orbit equivalent if and only if their associated Deaconu groupoids are isomorphic as topological groupoids. We also show that the equivalence class of Cuntz-Pimsner groupoids and the stably isomorphism class of Cuntz-Pimsner algebras of self-similar groups are invariants for orbit equivalence of limit dynamical systems.

• 복식
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• 제31권
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• pp.165-188
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• 1997

This study aims at 1) examining the perceived importance of clothing norms 2) examining relationship between perceptions of clothing norms clothing behavior and psycho-logical variables-ego identity(uniqueness and self acceptance) and sex role identity and 3) ascertaining any significant differences in the level of the perceived importance of clothing norms among variables-sex role identity and the uniqueness in psychological variables-and which variables are influencingon perception of clothing norms. The perception of cloth in norms inventory clothing norms inventory clothin behavior inventory ego identity in-ventory and the Bem Sex Role Inventory were administered to 620 college students. Sex role identity was classified into androgynous mas-culine feminine and undifferentiated type. Subjects were asked to rate each statement on the clothing norms under two kinds of instructions: their attitudes(TATT) and their beliefs about the expectations of others toward clothing norms(TBEO). 1) The scores of 3 TBEO of the students were higher than the scores of TATT. But the scores of TBEO concerning modesty of students were lower than the scores of TATT. Discrepancy scores of TATT and TBEO of the students were revealed significances differently according to clothing norms. males lower and higher class students had more free attitudes to the norms concerning genaral clothing attitudes. Females and higher class students had less free attitudes to the clothing norms concerning modesty. Females and lower and higher class students had more free attitudes to the norms concening sex-role related clothing attitudes but male students had less free to the sex-role related clothing norms. 2) Significant negative correlations between each variable of clothing norms and conform-ity-individuality were found. But negative correlations between those variables of the males and lower class students were higher than the correlations of the female and higher class students and the former had more posi-tive relationships with clothing norms and con-formity as compared with the latter. And sig-nificant positive correlations between each variable of clothing norms and modesty were found. But positive correlations between those variables of the males females and higher class students were higher than the correlations of the lower class students and the latter had less positive relationship with clothing norms and modesty as compared with the former. 3) Significant negative correlations between clothing norms and uniqueness were found in the subjects groups. The females and lower class students had more negative relationships with clothing norms and uniqueness as compared with the male and higher class students. Significant positive correlations be-tween uniqueness and conformity-individuality were found in all subjects groups, Therefore the higher uniqueness the student have the less they perceive theimportance of clothing norms and the more they have individuality. Significant positive correlations between sex-role related(higher class) general(female) clothing norms and self acceptance were found. but significant negative correlations be-tween campus style(higher class) general(female) clothing norms and self acceptance were found. But significant negative correlations be-tween campus style(males lower class, higher class) clothing norms and self acceptance were found. Clothing norms therfore related posi-tively or negatively with self acceptance ac-cording to the subjects groups. And significant negative correlations between conformity in-dividuality and self acceptance was found in higher class students. 4) The female masculine groups and the masculine groups of lower class revealed high scores than the scores of andrgynous group and undifferentiated group in clothing norms concerning modesty. And the feminine group revealed high scores in conformity-individu-ality than the scores of the masculine group. Male masculine and feminine group revealed high scores in clothing norms concerning cam-pus style than the scores of the androgynous group. The masculine group and feminine group of the lower classes revealed high scores in general clothing norms than the scores of the androgynous group. 5) The most influencing variables on the clothing norms were sex conformity-individu-altiy and masculine-feminine variables in the right order. The general clothing norms and clothing norms concerning modesty were influened by the sex role identity but the sex role related clothing norms and clothing norms concerning campus style were influenced by the ego identity. 6) Based on the sum scores of the uniqueness each group of the subjects was separately segmened into "high medium and low" groups. By the analysis of variances sig-nificant differences in discrepancy scores of TBEO and TATT among 3 uniqueness level groups were found on all clothing norms variables in all students three clothing norms variables in male and female students and one clothing norms variable in lower and higher students and in each clothing norms variable the mean discrepancy scores of the high uniqueness group were higher than those of the other groups. The findings indicated that the differences in the discrepancy score mainly contributed to the results of correla-tions described above.bed above.