• Journal of the Korean Mathematical Society
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• v.55 no.4
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• pp.797-808
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• 2018

In [1], the authors generalize the concept of the class group of an integral domain $D(Cl_t(D))$ by introducing the notion of the S-class group of an integral domain where S is a multiplicative subset of D. The S-class group of D, $S-Cl_t(D)$, is the group of fractional t-invertible t-ideals of D under the t-multiplication modulo its subgroup of S-principal t-invertible t-ideals of D. In this paper we study when $S-Cl_t(D){\simeq}S-Cl_t(D_T)$, where T is a multiplicative subset generated by prime elements of D. We show that if D is a Mori domain, T a multiplicative subset generated by prime elements of D and S a multiplicative subset of D, then the natural homomorphism $S-Cl_t(D){\rightarrow}S-Cl_t(D_T)$ is an isomorphism. In particular, we give an S-version of Nagata's Theorem [13]: Let D be a Krull domain, T a multiplicative subset generated by prime elements of D and S another multiplicative subset of D. If $D_T$ is an S-factorial domain, then D is an S-factorial domain.

• Communications of the Korean Mathematical Society
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• v.32 no.2
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• pp.353-359
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• 2017

Starting from a t-norm T, it is possible to construct a class of new t-norms, so-called T-generalized t-norm. The purpose of this paper is to describe some properties of this class of generalized t-norms. An algebraic structure as well as a binary relation among t-norms are also investigated. Some open problems are discussed as well.

• The korean journal of orthodontics
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• v.48 no.1
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• pp.63-70
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• 2018

Objective: The aim of this study is to quantitatively evaluate the stability of the skeletal and dental widths using cone-beam computed tomography (CBCT) after segmental Le Fort I osteotomy in adult patients with skeletal Class III malocclusion requiring maxillary expansion. Methods: In total, 25 and 36 patients with skeletal Class III malocclusion underwent Le Fort I osteotomy (control group) and segmental Le Fort I osteotomy (experimental group), respectively. Coronal CBCT images were used to measure the dental and skeletal widths before (T1) and after (T2) surgery and at the end of treatment (T3). The correlation between the extent of surgery and the amount of relapse in the experimental group was also determined. Results: In the control group, the dental width exhibited a significant decrease of $0.70{\pm}1.28mm$ between T3 and T2. In the experimental group, dental and skeletal expansion of $1.83{\pm}1.66$ and $2.55{\pm}1.94mm$, respectively, was observed between T2 and T1. The mean changes in the dental and skeletal widths between T3 and T2 were $-1.41{\pm}1.98$ and $-0.67{\pm}0.72mm$, respectively. There was a weak correlation between the amount of skeletal expansion during segmental Le Fort I osteotomy and the amount of postoperative skeletal relapse in the experimental group. Conclusions: Maxillary expansion via segmental Le Fort I osteotomy showed good stability, with a skeletal relapse rate of 26.3% over approximately 12 months. Our results suggest that a greater amount of expansion requires greater efforts for the prevention of relapse.

• The korean journal of orthodontics
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• v.45 no.5
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• pp.226-235
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• 2015

Objective: The purpose of this retrospective study was to investigate short-term and long-term skeletodental outcomes of Class III activator treatment. Methods: A Class III activator treatment group (AG) comprised of 22 patients (9 boys, 13 girls) was compared with a Class III control group (CG) comprised of 17 patients (6 boys, 11 girls). The total treatment period was divided into three stages; the initial stage (T1), the post-activator treatment or post-mandibular growth peak stage (T2), and the long-term follow-up stage (T3). Cephalometric changes were evaluated statistically via the Mann-Whitney U-test and the Friedman test. Results: The AG exhibited significant increases in the SNA angle, ANB angle, Wits appraisal, A point-N perpendicular, Convexity of A point, and proclination of the maxillary incisors, from T1 to T2. In the long-term follow-up (T1-T3), the AG exhibited significantly greater increases in the ANB angle, Wits appraisal, and Convexity of A point than the CG. Conclusions: Favorable skeletal outcomes induced during the Class III activator treatment period were generally maintained until the long-term follow-up period of the post-mandibular growth peak stage.

• The Journal of the Convergence on Culture Technology
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• v.7 no.3
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• pp.277-284
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• 2021

This study was conducted to confirm the effect on self-efficacy and critical thinking disposition by applying flip learning class to fundamental nursing practice education for nursing students. The study subjects were 42 people in the experimental group and 40 people in the control group who were allowed to participate in the study. Data analysis was statistically processed using SPSS/WIN 24.0 program. As a result of this study, the self-efficacy score of the experimental group who received the flipped learning class increased significantly immediately after class (t=3.49, p=.001) compared to before class, and 10 weeks after class (t=-0.75, p=.456), the effect persisted. The critical thinking disposition score of the experimental group increased significantly immediately after class (t=3.49, p=.001) compared to before class, and the effect persisted 10 weeks after class (t=0.11, p=.913). However, there was no significant difference in the academic self-efficacy and critical thinking disposition scores of the control group who received lecture classes. In other words, it was confirmed from the results of this study that fundamental nursing practice classes applied with flip learning are effective in improving self-efficacy and critical thinking disposition of nursing students. Based on this study, it is suggested that the application of flip learning method should be expanded in the major subject of nursing science.

• The korean journal of orthodontics
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• v.50 no.3
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• pp.170-180
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• 2020

Objective: To compare short- and long-term dentoalveolar, skeletal, and rotational changes evaluated by Björk's structural method of superimposition between children with Class II malocclusion treated by functional appliances and untreated matched controls. Methods: Seventy-nine prepubertal or pubertal children (mean age, 11.57 ± 1.40 years) with Class II malocclusion were included. Thirty-four children were treated using an activator with a high-pull headgear (Z-activator), while 28 were treated using an activator without a headgear (E-activator). Seventeen untreated children were included as controls. Lateral cephalograms were obtained before treatment (T1), after functional appliance treatment (T2), and after retention in the postpubertal phase (T3). Changes from T1 to T2 and T1 to T3 were compared between the treated groups and control group using multiple linear regression analysis. Results: Relative to the findings in the control group at T2, the sagittal jaw relationship (subspinale-nasion-pogonion, p < 0.001), maxillary prognathism (sella-nasion-subspinale, p < 0.05), and condylar growth (p < 0.001) exhibited significant improvements in the Z- and E-activator groups, which also showed a significantly increased maxillary incisor retraction (p < 0.001) and decreased overjet (p < 0.001). Only the E-activator group exhibited significant backward rotation of the maxilla at T2 (p < 0.01). The improvements in the sagittal jaw relationship (p < 0.01) and dental relationship (p < 0.001) remained significant at T3. Condylar growth and jaw rotations were not significant at T3. Conclusions: Functional appliance treatment in children with Class II malocclusion can significantly improve the sagittal jaw relationship and dental relationships in the long term.

• Journal of the Korea Society of Computer and Information
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• v.27 no.8
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• pp.253-261
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• 2022

In this study, the educational effect were sought to be identified after developing and applying project learning for the artificial intelligence based liberal arts education for the non-computer majors. A paired-sample t-test was performed within each group to determine the extent of improvement in the learning flow and artificial intelligence efficacy in the experimental and control groups. After class, an independent sample t-test was performed to examine the statistical effects of pre-test and post-test on the learning flow and artificial intelligence efficacy in the experimental and control groups. The experimental group and control group demonstrated significant improvements in the learning flow and artificial intelligence efficacy before and after class, each respectively. There was no statistically significant difference in the learning flow between the experimental group for which the project learning method was applied and the control group for which only theory and practice were conducted in the artificial intelligence class. It was also confirmed that the experimental group for which the project learning method was applied improved the efficacy of artificial intelligence to a significant level compared to the control group which only proceeded with theory and practice.

• Journal of the Korean School Mathematics Society
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• v.4 no.2
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• pp.103-113
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• 2001

The teaching-learning method utilizing Web makes it possible for the students take the initiative in any field and offers the teaching strategy, methodology and teaching-learning materials suitable for students' ability and standard. The purpose of this study is to investigate the characteristics of WBI in mathematics class for the effective teaching and learning focusing on the unit 'Function' in the 1st grade of middle school and verify its effectiveness by developing the WBI programs which can progress learning achievement and applying them to math class. Two hypotheses were established for this study. Hypothesis 1 : There will be meaningful difference between the group that studies under WBI and the one that doesn't, Hypothesis 2 : There will be meaningful difference in the attitude and interest toward learning between the group that studies under WBI and the one that doesn't. In order to find out the result, I have made a comparative analysis through t-verification on the object of two classes of the 1st grade in P middle school that I have been working for. The result shows that the class utilizing WBI is more effective than the traditional lecture-oriented class since there is a meaningful difference between the control group and experimental one and also that the class based on WEB has a great influence on students' interest and positive attitude toward math class.

• The Journal of Korean Academic Society of Nursing Education
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• v.16 no.2
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• pp.202-212
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• 2010

Purpose: The purpose of this study was to identify the effectiveness of the JigsawⅣ cooperative learning in a facilitative communication class of nursing students. Achievement, communication skill, self-directed learning and experience during the class were measured. Method: This study was a pretest and posttest design with two subject groups. 43 students were in experimental (JigsawⅣ) group and 47 ones were in control (general small discussion) group. Classes were conducted over a 6-week period. The collected data was analyzed by the SPSS 12.0 program. Result: After taking part in the educational program, the experimental group had significantly more improvement in communication skill (F=6.81, p=.002) and self-directed learning (F=11.81, p=.000). In addition, the experimental group showed significantly higher scores for concentration in the class (t=2.26, p=.27), positive emotional state (t=3.01, p=.003) and active participation (t=2.78, p=.007) compared to the control group. However, the achievement between the two groups was not significantly different (F=3.29, p=.073). Conclusion: The findings of this study show that JigsawⅣ cooperative learning has positive effects in improvement of communication skill and self-directed learning. Also, students were excited and interested in the class during cooperative learning. Based on these findings, the author suggests developing additional educational programs focusing on nursing students.

• Journal of Internet of Things and Convergence
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• v.9 no.2
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• pp.33-40
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• 2023

This study was aimed at examining the effects of aroma blending oil inhalation on academic stress and class concentration in nursing students. The research design was a nonequivalent placebo control group nonsynchronized. The subjects of the study were 24 students in the treatment group and 24 placebo control group. Data collection was from November 4, 2022 to December 3, 2022, and the data were analyzed chi-square test, independent t-test, paired t-test using the SPSS 23.0 Program. The treatment group inhaled aroma blending oil for 10 days showed a significant decrease in academic stress (t=-8.79, p<.001) and a significant increase in class concentration (t=24.44, p<.001).