• Bulletin of the Korean Mathematical Society
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• v.61 no.1
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• pp.13-27
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• 2024

A regular t-balanced Cayley map on a group Γ is an embedding of a Cayley graph on Γ into a surface with certain special symmetric properties. We completely classify regular t-balanced Cayley maps for a class of split metacyclic 2-groups.

• Hwankyungkyoyuk
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• v.20 no.4
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• pp.166-179
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• 2007

The purpose of this study is to find a concrete plan by examining effect of environmental education program on Environment-friendly Attitudes in sixth grade elementary school and to testify the educational values of environmental education program. The study was carried out by 32 students, which was experimental group and by 32 students, control group, in the sixth grade of Y elementary school located in yangjung, Busan city. Both group was found out the same quality group through the pre-test. Environmental class using environmental education program was applied to experimental group and traditional lecture class was applied to control group. After executing post-test to each group, comparative analysis was conducted by t-test using a SPSS 12.0 program. The result of post-test showed that experimental group taken environmental class using environmental education program was more statistically meaningful than control group taken traditional lecture class in the cognitive, emotional, behavioral area. As a result, in sixth grade elementary school environmental class using a environmental education program was more effective in knowledge-acquirement about the overall environ mental programs, and in fostering Environment-friendly Attitudes and behaviors than traditional lecture class. The teacher must develop efficient environment education program in such side.

• Bulletin of the Korean Mathematical Society
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• v.53 no.2
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• pp.601-614
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• 2016

Let $N_{g,s}$ denote the nonorientable surface of genus g with s boundary components. Recently Paris and Szepietowski [12] obtained an explicit finite presentation for the mapping class group $\mathcal{M}(N_{g,s})$ of the surface $N_{g,s}$, where $s{\in}\{0,1\}$ and g + s > 3. Following this work, we obtain a finite presentation for the subgroup $\mathcal{T}(N_{g,s})$ of $\mathcal{M}(N_{g,s})$ generated by Dehn twists.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.5
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• pp.417-425
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• 2020

This study was conducted to identify the effects of baby care using dolls on nursing students' major satisfaction, class satisfaction, and knowledge of newborn care. A quasi-experimental nonequivalent control group, pretest-posttest design was used. The subjects of the study were 95 nursing college students who agreed to participate. The control group (n=47) received lecture education consisting of watching newborn videos while the experimental group (n=48) received a practical education involving caring for a doll resembling an infant. Data were collected from March to May, 2019 and analyzed using descriptive statistics, χ²-tests, and t-tests with the SPSS/WIN 21.0 program. The major satisfaction score of the experimental group was higher than that of the control group, but it was not statistically significant (t=1.64, p=.107). The score for class satisfaction differed significantly between the experimental group and control group (t=2.08, p=.043). The knowledge of newborn care score for the experimental group was higher than that for the control group, and there was a statistically significant difference (t=-5.82, p<.001). Overall, the results show that baby care using a doll has positive effects on class satisfaction and knowledge of newborn care. In the future, it will be necessary to develop and apply effective teaching methods in line with the times.

• The korean journal of orthodontics
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• v.45 no.4
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• pp.171-179
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• 2015

Objective: To compare dentoalveolar and skeletal changes produced by the pendulum appliance (PA) and the distal screw appliance (DS) in Class II patients. Methods: Forty-three patients (19 men, 24 women) with Class II malocclusion were retrospectively selected for the study. Twenty-four patients (mean age, $12.2{\pm}1.5years$) were treated with the PA, and 19 patients (mean age, $11.3{\pm}1.9years$) were treated with the DS. The mean distalization time was 7 months for the PA group and 9 months for the DS group. Lateral cephalograms were obtained at T1, before treatment, and at T2, the end of distalization. A Mann-Whitney U test was used for statistical comparisons of the two groups between T1 and T2. Results: PA and DS were equally effective in distalizing maxillary molars (4.7 mm and 4.2 mm, respectively) between T1 and T2; however, the maxillary first molars showed less distal tipping in the DS group than in the PA group ($3.2^{\circ}$ vs. $9.0^{\circ}$, respectively). Moreover, significant premolar anchorage loss (2.7 mm) and incisor proclination ($5.0^{\circ}$) were noted in the PA group, whereas premolar distal movement (1.9 mm) and no significant changes at the incisor ($0.1^{\circ}$) were observed in the DS group. No significant sagittal or vertical skeletal changes were detected between the two groups during the distalization phase. Conclusions: PA and DS seem to be equally effective in distalizing maxillary molars; however, greater distal molar tipping and premolar anchorage loss can be expected using PA.

• Journal of the Chungcheong Mathematical Society
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• v.23 no.3
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• pp.547-553
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• 2010

In this paper we prove that real quadratic function field F over ${\mathbb{F}}_q(T)$ has infinite 2-class field tower if the 4-rank of narrow ideal class group of F is equal to or greater than 4 when $q{\equiv}3$ mod 4.

• BMB Reports
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• v.31 no.6
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• pp.525-535
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• 1998

A critical step in the faithful translation of genetic information is specific tRNA recognition by aminoacyl-tRNA synthetases. These enzymes catalyze the covalent attachment of particular amino acids to the terminal adenosine of cognate tRNA substrates. In general, there is one synthetase for each of the twenty amino acids and each enzyme must discriminate against all of the cellular tRNAs that are specific for the nineteen noncognate amino acids. Primary sequence information combined with structural data have resulted in the division of the twenty synthetases into two classes. In recent years, several high-resolution co-crystal structures along with biochemical data have led to an increased understanding of tRNA recognition by synthetases of both classes. The anticodon sequence and the amino acid acceptor stem are the most common locations for critical recognition elements. This review will focus on acceptor stem discrimination by class II synthetases. In particular, the results of in vitro aminoacylation assays and site-directed and atomic group mutagenesis studies will be discussed. These studies have revealed that even subtle atomic determinants can provide signals for specific tRNA aminoacylation.

• Journal of Korean Elementary Science Education
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• v.33 no.1
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• pp.69-81
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• 2014

This study was to find out the effects of out-of-class environmental experience learning on elementary students' environmental literacy. For this study, we developed and applied environmental education program utilizing out-of-class facilities and ecological park for the 5th-grade students. The subjects of this study were the 5th grade students of an elementary school located in Si-hung city. The study was carried out for two groups, an experiment group of 29 students and control group of 29 students. The education program using out-of-class environmental experience learning was provided to the experiment group while lecture-oriented education program was provided to the control group. The questionnaire used in this study to assess the environmental literacy of the study objects consists of 41 questions under 4 domains (knowledge, emotion, skill, behavior). After observing and analyzing the effects of out-of-class environmental experience learning on students' environmental literacy, we found that the program using the out-of-class environmental experience learning posed greater impacts than lecture-oriented program. By domains, environmental literacy in 3 domains illustrated positive improvement. In particular, skill domain illustrated much more improvement in environmental literacy. But, domain of behavior didn't illustrated improvement in environmental literacy. The result of this study signified that the out-of-class environmental experience learning has positive and effective impact on the environmental literacy. And out-of-class environmental experience learning is more suitable to improve the skill domain of the environmental literacy than lecture-oriented learning. But, it is couldn't improve the domain of behavior. Therefore, in order to improve behavior domain, the program must apply with effective evaluation and home training.

• Journal of People, Plants, and Environment
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• v.24 no.6
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• pp.595-608
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• 2021

Background and objective: For effective horticultural education, it is required to develop kits for practice. In this study, we developed a horticultural kit for germination that introduces storytelling, characterization, and assembly, and investigated the educational effects of using it to study its educational differentiation and usefulness. Methods: First, we developed a seed germination kit for learning. It consists of three components: the kit main frame for hydroponics, the activity sheet for storytelling, and the instruction manual. It is made into an acrylic assembly in consideration of the ease of delivery for contactless learning. Second, we developed two programs, each using a germination kit for horticultural education (experimental group) and a general germination kit program (control group). At this time, the class consists of pre-questionnaire, the 1st and 2nd classes, observation log writing (total six times for two weeks), the 3rd class, and post-questionnaire. The experimental group and control group were separately executed. Third, the application results were compared and analyzed before and after class. As a quantification questionnaire, the effects before and after class were compared through t-test with a questionnaire on program satisfaction and attitude change toward plants. The quantitative results were analyzed through observation activity sheets and effects before and after the class were analyzed through t-test with quantification and language coding. Results: The effect of horticulture education using the developed kit was estimated by a quantification questionnaire. Both the program satisfaction and the change in attitude toward plants showed high in the experimental group, and this difference was statistically significant (p < .05). As a result of analyzing the observation paper with a qualitative questionnaire, various cognitive and affective expressions appeared in the experimental group as well as the contents of the observation paper. The number of syllables and various qualitative expressions appeared, and these differences were also statistically significant (p < .05). Conclusion: Compared to general germination activities, it was found that the germination activities using storytelling-based horticultural kits would be effective for contactless classes in the post-COVID-19 era and in increasing the educational effect of horticultural activities.

• 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.