• East Asian mathematical journal
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• v.34 no.5
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• pp.587-595
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• 2018

In [9], Lee and Sakuma constructed 2-generator non-Hopfian groups each of which has a specific presentation ${\langle}a,b{\mid}R{\rangle}$ satisfying small cancellation conditions C(4) and T(4). In this paper, we prove the SQ-universality of those non-Hopfian groups.

• Journal of the Korean School Mathematics Society
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• v.4 no.2
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• pp.125-134
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• 2001

It is necessary that at any rate we try to decrease underachievers by learning deficiency in mathematics to extreme limits under circumstances that mathematics becomes more requisite daily in the 21st century's informative society. However, the traditional teaching method causes a lot of problems in elevating the needed ability for the newly changing society. Accordingly, for the purpose of letting underachievers by learning deficiency have much interest in mathematics, seek the qualitative elevation, have the feelings of self-confidence and accomplishments, escape from desperation, and also teachers choose the activities of small groups, design teaching plans, apply those to teaching-learning activities and finally verify the effect, this researcher sets up a hypothesis as follows: 1. The teaching method through small groups will be effective for the accomplishments of underachievers in mathematics. 2. Its method will bring out the meaningful change in the emotional areas of mathematics. Therefore, so as to prove the above hypothesis, the results through the theoretical approach and practicing teaming by small groups have turned out to be positive.

• Journal of the Korean earth science society
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• v.41 no.3
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• pp.307-319
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• 2020

The purpose of this study was to determine whether there are differences in the verbal interactions of earth science gifted depending on their communications structures and group status in small group activities. To this end, a small group activity was conducted to measure the density of the earth, and 8 small groups were selected, including 4 co-ownership type and 4 monopolistics type groups with different communication structures. And then, the framework was developed for analyzing verbal interactions to compare the differences in characteristics between small groups. The results are as follows. First, regardless of the communication structures, there were showing a simple pingpong-type communication structures for all small groups. Second, negative interactions such as 'restraint', 'command', 'complaint', and 'lack of confidence' predominantly appeared in all small groups. Third, the students in the status of out-lookers in small groups were mainly verbal interactions, such as instructing the other person, acting against the other person's actions, and expressing dissatisfaction with the attitudes and abilities of members. Therefore, teachers should guide students to use higher-level verbal interactions in their group activities in small group activities, and engage in students communication to prevent negative interactions from occurring. The teachers also need to check the level of achievement for students in the status of out-lookers in advance and guide them to participate more actively in small group activities. This study is meaningful in that it can be sued to design teaching and learning to improve students' problem solving and communication skills.

• Journal of Korean Elementary Science Education
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• v.39 no.3
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• pp.323-337
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• 2020

To achieve effective learning, knowledge must be shared and developed through interaction with peer learners. Therefore, science education emphasizes small group inquiry activities that solves tasks through the interaction of members. The effect of small group inquiry activities depends on how to compose small groups. The way in which a group is composed is a very important factor for improving interaction. In particular, it has been reported that the gender of peer is a very important factor in the interaction between students in the composition of small groups. Meanwhile, studies are being conducted on the types and stability of verbal interactions in small group inquiry activities using social network analysis. The purpose of this study is to analyze the types and stability of verbal interaction types and stability according to gender-grouping in elementary school students' small group activities using social network analysis. To this end, 60 5th graders in elementary school were conducted with different gender in the composition of the group of male, female and mixed-gender students. The study found that the composition of a group by gender had little impact on the type or stability of verbal interaction. However, the frequency of verbal interactions was higher in mixed-gender groups than in other groups. Through this process, the gender-grouping in elementary school students' small group activities suggests a mixed-gender group.

• Korean Journal of Childcare and Education
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• v.12 no.5
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• pp.91-113
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• 2016

This study aims to find out the significance in the experiences of voluntary participation in small groups by mothers of young children. As a result of the interviews conducted by targeting five mothers, the total was divided into three categories and six sub-factors. First, mothers voluntarily participated in small groups. Free from the role of mother and wife, they focused on their real selves, and had experiences of emotional support by forming close relationships with people. Second, mothers did not just participate in small groups as a hobby, but tried to be role models that help the growth of their children. They also tried to be the catalyst that helps create positive changes in their children and husbands. Third, mothers had social experiences, participated in economic activities as members of society or exerted their capabilities through active exchange with other people. Finally, this research hopes to provide the community with parent education-related implications that can have a positive impact on mothers themselves, their families and society.

• Journal of Astronomy and Space Sciences
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• v.29 no.3
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• pp.245-251
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• 2012

Since the development of surface magnetic features should reflect the evolution of the solar magnetic field in the deep interior of the Sun, it is crucial to study properties of sunspots and sunspot groups to understand the physical processes working below the solar surface. Here, using the data set of sunspot groups observed at the ButterStar observatory for 3,364 days from 2002 October 16 to 2011 December 31, we investigate temporal change of sunspot groups depending on their Z$\ddot{u}$rich classification type. Our main findings are as follows: (1) There are more sunspot groups in the southern hemisphere in solar cycle 23, while more sunspot groups appear in the northern hemisphere in solar cycle 24. We also note that in the declining phase of solar cycle 23 the decreasing tendency is apparently steeper in the solar northern hemisphere than in the solar southern hemisphere. (2) Some of sunspot group types make a secondary peak in the distribution between the solar maximum and the solar minimum. More importantly, in this particular data set, sunspot groups which have appeared in the solar southern hemisphere make a secondary peak 1 year after a secondary peak occurs in the solar northern hemisphere. (3) The temporal variations of small and large sunspot group numbers are disparate. That is, the number of large sunspot group declines earlier and faster and that the number of small sunspot group begins to rise earlier and faster. (4) The total number of observed sunspot is found to behave more likewise as the small sunspot group does. Hence, according to our findings, behaviors and evolution of small magnetic flux tubes and large magnetic flux tubes seem to be different over solar cycles. Finally, we conclude by briefly pointing out its implication on the space weather forecast.

• Research in Mathematical Education
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• v.23 no.4
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• pp.219-233
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• 2020

Teachers' intervention in small groups is a research area that needs more research attention. Ehrenfeld and Horn (2020) identified teachers' group work monitoring routines that consist of four recurrent talk moves: 1) Initiation, 2) Entry, 3) Focus, and 4) Exit. To better understand prospective teachers' (PTs) intervention in small groups in mathematics classrooms, I investigated how PTs' intervention actions and purposes are related to the monitoring routines, particularly, in terms of Focus moves. I analyzed 26 PTs' responses to four written scenarios, each of which depicts interactions among students in a small group. I identified 1) types of PTs' math talk, 2) types of PTs' non-math talk, 3) types of intervention purposes, and 4) patterns of intervention actions and purposes by scenario. This study contributes to understanding PTs' intervention actions and purposes in mathematics instruction.

• Journal of Acupuncture Research
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• v.23 no.4
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• pp.175-185
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• 2006

Objectives : This study was designed to investigate effects of electro-acupuncture's stimulated frequency, intensity, duration at 5736 on tile Small Intestine Motility in Rats. Methods The motor activity of small intestine in rats was evaluated by intestinal transportation rate. Changes in tile motility of ileum in vivo was measured at 10 minutes after electro-acupuncture. Various kinds of stimulus-frequency were used in this experiment: 2 Hz, 50 Hz, 100 Hz, 2 Hz-4 trains, 8 Hz groups treated with EA of the condition in S mA, 1 ms pulse duration, 30 minutes stimulated duration. Three different stimulus-intensity were used: 1, 5, 10 mA groups treated with EA of the condition in 2 Hz, 1 ms pulse duration, 30 minutes stimulated duration. Six different stimulus-duration were used: 10, 20, 30, 40, 50, 60 minutes groups treated with EA of the condition in 2 Hz, 5 mA, 1 ms pulse duration. Results : 2 and 100 Hz groups significantly increased the small intestine motility, but 50 Hz group did not induce a significant change. Besides, small intestine motility was significantly increased only in 5 mA intensity (5 times twitch). futhermore, at least 20 minutes EA treatment was necessary to increase the small intestine motility. Conclusion : Those basic data form this study can be applied to established the effective treatment of EA for gastrointestinal diseases in the clinical field.

• Journal of Nutrition and Health
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• v.28 no.9
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• pp.825-833
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• 1995

This study was performed to investigate the influence of dietary fiber, which from whole food on the serum lipid level and bowel function in rats. The fiber sources of experimental diets were prepared by drying and milling of small water dropwort(WD), mugwort(MW), butterbur(BB) and apple(AP). Each fiber sources was mixed at the 15% level of the diet. The level of dietary fiber in WD, MW, BB diets was similar but that in AP diet was slightly low. Male rats of Sprague-Dawley strain were blocked into 5 groups ; WD, MW, BB, AP, FF(fiber free). The animals were fed ad libitum each of experimental diets for 37 days. Food intake of AP and FF groups were than other groups, FF group was lower than other grous in food efficiency ratio. MW group showed highest level in fecal weight and fecal water content and group has the longest transit time compare to other groups. Serum triglyceride level was not significantly different among groups. BB group showed the lowest level in the serum total cholesterol. WD and MW groups showed slightly higher level in the serum HDL cholesterol than other groups. Mucosa weight was not significantly different among groups. The activity of maltase in mucosa of small intestine was highest in FF groups. Absorption rates of calcium were not significantly different among groups. Absorption rate of magnesium was higher in FF group compare to others. And, absorption rates of phosphorus in MW and FF groups were slightly lower than other groups.

• Journal of Ecology and Environment
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• v.41 no.8
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• pp.223-234
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• 2017

Background: Spatial structure of plants in a population reflects complex interactions of ecological and evolutionary processes. For dioecious plants, differences in reproduction cost between sexes and sizes might affect their spatial distribution. Abiotic heterogeneity may also affect adaptation activities, and result in a unique spatial structure of the population. Thus, we examined sex- and size-related spatial distributions of old-growth forest of dioecious tree Torreya nucifera in extremely heterogeneous Gotjawal terrain of Jeju Island, South Korea. Methods: We generated a database of location, sex, and size (DBH) of T. nucifera trees for each quadrat ($160{\times}300m$) in each of the three sites previously defined (quadrat A, B, C in Site I, II, and III, respectively). T. nucifera trees were categorized into eight groups based on sex (males vs. females), size (small vs. large trees), and sex by size (small vs. large males, and small vs. large females) for spatial point pattern analysis. Univariate and bivariate spatial analyses were conducted. Results: Univariate spatial analysis showed that spatial patterns of T. nucifera trees differed among the three quadrats. In quadrat A, individual trees showed random distribution at all scales regardless of sex and size groups. When assessing univariate patterns for sex by size groups in quadrat B, small males and small females were distributed randomly at all scales whereas large males and large females were clumped. All groups in quadrat C were clustered at short distances but the pattern changed as distance was increased. Bivariate spatial analyses testing the association between sex and size groups showed that spatial segregation occurred only in quadrat C. Males and females were spatially independent at all scales. However, after controlling for size, males and females were spatially separated. Conclusions: Diverse spatial patterns of T. nucifera trees across the three sites within the Torreya Forest imply that adaptive explanations are not sufficient for understanding spatial structure in this old-growth forest. If so, the role of Gotjawal terrain in terms of creating extremely diverse microhabitats and subsequently stochastic processes of survival and mortality of trees, both of which ultimately determine spatial patterns, needs to be further examined.