• Communications of the Korean Mathematical Society
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• v.17 no.4
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• pp.709-718
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• 2002

Observing that each Tychonoff space X has the minimal basically disconnected cover (ΛX, Λ$\sub$X/) and the .realcompact-ification $\upsilon$X, we introduce a concept of stable $\sigma$Z(X)#-ultrafilters and give internal characterizations of Tychonoff spaces X for which Λ($\upsilon$X) : $\upsilon$(ΛX).

• Kyungpook Mathematical Journal
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• v.46 no.3
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• pp.445-448
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• 2006

Let N be a normal subgroup of a path-connected topological group (G, $t$). In this paper, the authors consider the existence of path-connectedness in refined topologies in order to address the property of maximal path-connectedness in topological groups. In particular, refinements on $t$ and refinements on the quotient topology on G/N are studied. The preservation of path-connectedness in extending topologies and translation topologies is also considered.

• Kyungpook Mathematical Journal
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• v.49 no.3
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• pp.403-410
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• 2009

In this paper, we make use of the weight to obtain some two-weight integral inequalities which are generalizations of the Poincar$\'{e}$ inequality. These inequalities are extensions of classical results and can be used to study the integrability of differential forms and to estimate the integrals of differential forms. Finally, we give some applications of this results to quasiregular mappings.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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• pp.1129-1132
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• 2005

Based on a discrete-time version of the distributional Little's law, we present a simple computational procedure to obtain the queue-length distribution of the discrete-time GI/G/1 queue from its waiting-time distribution that is available by various existing methods. We also discuss our numerical experience and address a couple of remarks on possible extensions of the procedure.

• Communications of the Korean Mathematical Society
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• v.11 no.4
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• pp.967-974
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• 1996

We discuss contraction operators T in the class A, where A is the class of absolutely continuus contractions for which the Sz.-Nagy-Foias functional calculus is isometry. We obtain relationship between the class $A_{n, \aleph_0}$ and hereditary property $(\tilde{P}_n)$.

• Korean Management Science Review
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• v.12 no.1
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• pp.139-156
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• 1995

This study addresses basic requirements for mathematical programming software, discusses considerations in designing these software, implementation issues facing in these types of applications development, and shows some examples of codes being developed in the course. This type of projects requires long and ever-changing evolutionary phases. The experience is therefore, valuaable in suggesting some useful hints which may be salvaged for similar projects as well as providing reusable codes. In particular, scanning and parsing the free-format inputs, symbol table management, mixed-language programming, and data structures dealing with large sparse matrices are indispensable to many management science software development. Extensions to be made are also discussed.

• Journal of the Korean Operations Research and Management Science Society
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• v.28 no.1
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• pp.37-49
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• 2003

Using the concept of closed queueing network, we present a consistent way of interpreting existing duality relations among queueing systems. Also, using embedded Markov chains, we present a few new duality relations for the queueing systems with negative customers.

• Communications of the Korean Mathematical Society
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• v.19 no.1
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• pp.35-51
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• 2004

We introduce fuzzy closure systems and fuzzy closure operators as extensions of closure systems and closure operators. We study relationships between fuzzy closure systems and fuzzy closure spaces. In particular, two families F(S) and F(C) of fuzzy closure systems and fuzzy closure operators on X are complete lattice isomorphic.

• Bulletin of the Korean Mathematical Society
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• v.39 no.3
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• pp.377-388
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• 2002

In this paper, we obtain an extension of an analogue of Hilbert's inequality involving series of nonnegative terms. The integral analogies of the main results are also given.

• Communications of the Korean Mathematical Society
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• v.29 no.1
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• pp.23-26
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• 2014

Let E be a graded central division algebra (GCDA) over a grade field R. Let S be an unramified graded field extension of R. We describe the grading on the underlying GCDA E' of $E{\otimes}_RS$ which is analogous to the valuation on a tame division algebra over Henselian valued field.