• Bulletin of the Korean Mathematical Society
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• v.37 no.1
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• pp.171-179
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• 2000

We prove the following: (1) For a Hausdorff space X, the hyperspace K(X) of compact subsets of X is hemicompact if and only if X is hemicompact. (2) For a regular space X, the hyperspace $C_K(X)$ of subcontinua of X is hemicompact (hemiconnected) if and only if X is hemicompact (hemiconnected). (3) For a locally compact Hausdorff space X, each open set in X is hemicompact if and only if each basic open set in the hyperspace K(X) is hemicompact. (4) For a connected, locally connected, locally compact Hausdorff space X, K(X) is hemiconnected if and only if X is hemiconnected.

• Bulletin of the Korean Mathematical Society
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• v.36 no.1
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• pp.203-207
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• 1999

In this paper, we find a condition of an open subset of the affine space which admits a cocompact affine action. To do it, the asymptotic flag of an open convex subset is introduced and some applications to affine manifolds are presented.

• Journal of the Korean Institute of Landscape Architecture
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• v.48 no.5
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• pp.89-106
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• 2020

This study examines the functionality and landscape design specifics of the outdoor space of representative commercial multi-complexes in Korea in order to overview the design trends of outdoor landscaping trends. Through surveying the composition of outdoor spaces along with their relation to the surrounding landscape, open spaces, and the neighboring communities, this paper identified the change in trends regarding the characteristics of outdoor landscape planning and acknowledged the enhanced public value of outdoor space. This study asserts that the characteristics of outdoor spaces can best be understood by examining the ways in which the outdoor space relates to adjoining commercial multi-complexes and the surrounding landscape. Focusing on the relationships that outdoor space establishes, commercial multi-complexes can be categorized as follows: in/outdoor separated type, in/outdoor semi-open type, surrounding landscape-projected type, and surrounding landscape-combined type. By studying the landscape design specifics of the outdoor space of representative cases of each type, the following has been concluded: First, the amount of outdoor space has expanded in terms of importance and function while serving to assist in various activities and participatory experiences, and no longer merely serves as a backdrop of commercial facilities. Second, with the strengthened connectivity between in/outdoor spaces, the elements of outdoor surroundings are more actively introduced indoors to improve amenities. Through directly connecting certain indoor program spaces with outdoor spaces, commercial multi-complexes tend to provide richer combined experiences. Third, with the expansion of outdoor space functionality, commercial multi-complexes are increasingly recognized as a quasi-public space, making good example of liminal space. In light of the recent case of development plans linked with public open spaces in suburban settings, commercial landscape design shows the possibility of creating an open space that can function as a center for local culture and green networks in the community.

• Journal of the Korea Society of Computer and Information
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• v.11 no.2 s.40
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• pp.201-211
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• 2006

The standardization of third Generation Partnership Project(3GPP) has been performed in of order to support interactive multimedia services under mobile environments. In this 3GPP, transmit diversity solutions are applied to increase the available diversity effectively using 2 or more antennas. In this paper, we analyzer the performances on STTD(Space Time Transmit Diversity) technique and its modified techniques such as STTD-OTD, CL-STTD, and 4TX-STTD out of open loop transmit diversities that the standardization of 3GPP has released. We also propose the open loop transmitter and receiver diversities to add the receiver diversity. We analyze and discuss the performance of the proposed techniques and using the Matlab simulation under the flat fading channel environment.

• Journal of the Korean Institute of Educational Facilities
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• v.16 no.5
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• pp.19-26
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• 2009

This study attempts to find out the spatial characteristics of the converging technology laboratory. For this, the understanding of the nature of converging technology and its necessary system requirements are crucial. The foremost concern lies in the 'flexibility' of the laboratory space, i.e. 'open-lab system', because of the multi-disciplinary spatial arrangement which is supposed to be open to a number of different research fields in the same building cluster. From the case analysis, this study reveals that in order to maximize the adjustability, the module based space unit plan should be considered at the earliest stage. In addition, it is also found from the analysis that the linkage of the communication spaces such as seminar room, auditorium, lounge, rest room, dining room, and corridors should be dealt with a higher degree of sophistication, since these facilitate the interaction of information at the behavioral level.

• Communications of the Korean Mathematical Society
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• v.26 no.2
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• pp.297-304
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• 2011

In this paper, we introduce closure operators [${\cdot}$]c and [${\cdot}$]a on a space and study some relations among [${\cdot}$]c, [${\cdot}$]a and countable tightness. We introduce the concepts of a strongly sequentially closed set and a strongly sequentially open set and show that a space X has countable tightness if and only if every strongly sequentially closed set is closed if and only if every strongly sequentially open set is open. Finally we find a generalization of the weak Fr$\'{e}$chet-Urysohn property which is equivalent to countable tightness.

• Bulletin of the Korean Mathematical Society
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• v.53 no.1
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• pp.205-214
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• 2016

Any open Riemann surface has a conformal model in any orientable Riemannian manifold of dimension 4. Precisely, we will prove that, given any open Riemann surface, there is a conformally equivalent model in a prespecified orientable 4-dimensional Riemannian manifold. This result along with [5] now shows that an open Riemann surface admits conformal models in any Riemannian manifold of dimension ${\geq}3$.

• Communications of the Korean Mathematical Society
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• v.32 no.1
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• pp.175-181
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• 2017

In this paper, we introduce a notion of cleanly covered topological spaces along with two strong separation axioms. Some properties of cleanly covered topological spaces are obtained in term of maximal open sets including some similar properties of a topological space in term of maximal closed sets. Two strong separation axioms are also investigated in terms of minimal open and maximal closed sets.

• Communications of the Korean Mathematical Society
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• v.27 no.3
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• pp.603-611
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• 2012

We introduce the concept of fuzzy $r$-minimal ${\alpha}$-open set on a fuzzy minimal space and some basic properties. We also introduce the concepts of fuzzy $r$-M ${\alpha}$-continuous and fuzzy $r$-M($M^*$) ${\alpha}$-open mappings, and investigate characterization for such mappings.

• Journal of Environmental Health Sciences
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• v.38 no.3
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• pp.213-222
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• 2012

Objectives: This study was undertaken in order to evaluate by work space zoning and structure the concentrations of biological contaminants in the indoor air of domestic office buildings. Methods: Air samples were collected in the office spaces of 15 office buildings in Seoul from June 28 to July 28, 2011. Prior to the sampling, each office was classified into 'open-plan office', 'cellular office' and 'mixed office' according to the work space zoning. To evaluate the biological contamination of indoor air, total suspended bacteria (TSB), Gram positive bacteria (GPB), Staphylococcus aureus (S.A), Methicillin-resistant Staphylococcus aureus (MRSA), Gram negative bacteria (GNB) and fungi were investigated. During the sampling, temperature, relative humidity and carbon dioxide ($CO_2$) were measured. Results: The TSB concentrations ($GM{\pm}GSD$) were $452({\pm}1.3)cfu/m^3$ in open-plan offices, $366({\pm}1.3)cfu/m^3$ in cellular offices and $287({\pm}1.5)cfu/m^3$ in mixed offices, and there were significant differences between the three groups (p<0.05). The highest concentrations ($GM{\pm}GSD$) of fungi were found in the indoor air of cellular offices $128({\pm}1.0)cfu/m^3$, which was at least three times higher than the concentrations in mixed offices $43({\pm}1.0)cfu/m^3$ (p<0.05). Conclusions: Microbiological contamination in the indoor air of office buildings by work space structure was the highest with the open-plan office layout which includes no high walls or doors separating the occupants.