• The KIPS Transactions:PartB
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• v.10B no.2
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• pp.205-212
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• 2003

ThruBook is a collaborative work platform based on ebook documents, supporting synchronized group work sessions. Using this platform, users can participate in a group session based on a same ebook, and share group actions synchronously. In this paper, we consider annotations as all kinds of additional data on ebooks, including bookmarks, memos, and figures. Also, model shared actions such as sharing/navigating these annotations. As a result, we could model all collaborative actions as annotations, and propose a collaborative work model as communicating annotation objects between session participants. This approach implemented in ThruBook platform could easily model shared actions in collaborative systems. The collaborative work platform implemented in ThruBook can be applied to other types of collaborative work systems.

• Journal of the Korean Mathematical Society
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• v.56 no.1
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• pp.53-65
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• 2019

Recently, Chung and Lee [2] introduced the notion of topological stability for a finitely generated group action, and proved a group action version of the Walters's stability theorem. In this paper, we introduce the concepts of continuous shadowing and continuous inverse shadowing of a finitely generated group action on a compact metric space X with respect to various classes of admissible pseudo orbits and study the relationships between topological stability and continuous shadowing and continuous inverse shadowing property of group actions. Moreover, we introduce the notion of structural stability for a finitely generated group action, and we prove that an expansive action on a compact manifold is structurally stable if and only if it is continuous inverse shadowing.

• Journal of the Korean Mathematical Society
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• v.43 no.6
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• pp.1183-1197
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• 2006

Let X be a smooth, closed, connected spin 4-manifold with $b_1(X)=0$ and signature ${\sigma}-(X)$. In this paper we use Seiberg-Witten theory to prove that if X admits a spin alternating $A_4$ action, then $b^+_2(X)$ ${\geq}$ |${\sigma}{(X)}$|/8+3 under some non-degeneracy conditions.

• Journal of the Chungcheong Mathematical Society
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• v.14 no.2
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• pp.27-35
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• 2001

We shall deal with ten cases out of 15 distinct almost Bieberbach groups up to Seifert local invariant. In those cases we will show that if G is a finite abelian group acting freely on the standard nilmanifold, then G is cyclic, up to topological conjugacy.

• Journal of the Chungcheong Mathematical Society
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• v.31 no.4
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• pp.475-486
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• 2018

We study free actions of finite nonabelian groups on 3-dimensional nilmanifolds with the first homology ${\mathbb{Z}}^2{\bigoplus}{\mathbb{Z}}_2$ which yield an orbit manifold reversing fiber orientation, up to topological conjugacy. We show that those nonabelian groups are $D_4$(the dihedral group), $Q_8$(the quaternion group), and $C_8.C_4$(the $1^{st}$ non-split extension by $C_8$ of $C_4$ acting via $C_4/C_2=C_2$).

• Journal of the Korean Mathematical Society
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• v.54 no.5
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• pp.1623-1639
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• 2017

The generalized coGottlieb sets are not known to be groups in general. We study some conditions which make them groups. Moreover, there are actions on the generalized coGottlieb sets which are different from known actions up to now. We give related exact sequence of the generalized coGottlieb sets. Using them, we obtain certain results related to the maps which preserve generalized coGottlieb sets.

• Journal of the Korean Mathematical Society
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• v.28 no.1
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• pp.65-78
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• 1991

• Hwankyungkyoyuk
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• v.17 no.1
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• pp.90-100
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• 2004

This study has the goal to modify ‘Investigating and Evaluating Environmental Issues and Actions’(IEEIA) instruction in the sense of Korean ecological sociocultural characteristics and ‘ecology and environment' curriculum and to assess the effects of modified IEEIA instruction on responsible environmental behavior and associated variables in high school student. A modified pre- and post-test nonequivalent control group design was utilized with 4 intact classes from J-high school at Seo-cheon, Chungcheongnamdo. Pre- and post-test data were collected on the following variables: responsible environmental behavior, knowledge of and skill in using environmental actions strategies, in-depth knowledge about issues, and locus of control. Analysis of t-test was used to compare pretest with posttest means of treatment group and control group. In treatment group, statistically significant differences between pretest and posttest were found with all variables. The treatment was found to be more effective than the control in increasing the variables of responsible environmental behavior, knowledge of and skill in using environmental actions strategies, and locus of control.

• Journal of the Korean Mathematical Society
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• v.56 no.1
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• pp.285-287
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• 2019

• Honam Mathematical Journal
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• v.41 no.4
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• pp.851-861
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• 2019

In this paper we consider proper semialgebraic actions of semialgebraic groups on semialgebraic sets. We prove the equivariant version of the semialgebraic local-triviality of semialgebraic maps.