• East Asian mathematical journal
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• v.23 no.1
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• pp.111-122
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• 2007

In this paper, we will show some relations between decomposition series {${\nu}^{\alpha}\;:\;{\alpha}$ is an ordinal } and supratopological series {${\sigma}_{\alpha}{\nu}\;:\;{\alpha}$ is an ordinal} for a neighborhood structure $\nu$ and the formular ${\sigma}_{\alpha}{\nu}\;=\;{\nu}^{({\omega}^{\alpha})}$, where $\omega$ is the first limit ordinal.

• The Pure and Applied Mathematics
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• v.29 no.1
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• pp.59-68
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• 2022

For a finite group G ⊂ GL(n, ℂ), the G-Hilbert scheme is a fine moduli space of G-clusters, which are 0-dimensional G-invariant subschemes Z with H⁰(𝒪_Z ) isomorphic to ℂ[G]. In many cases, the G-Hilbert scheme provides a good resolution of the quotient singularity ℂⁿ/G, but in general it can be very singular. In this note, we prove that for a cyclic group A ⊂ GL(n, ℂ) of type ${\frac{1}{r}}$(1, …, 1, a) with r coprime to a, A-Hilbert Scheme is smooth and irreducible.

• Bulletin of the Korean Mathematical Society
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• v.34 no.4
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• pp.549-560
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• 1997

For positive integers $n_i \geq 2, i = 1, 2, 3, 4$, such that $\Sigma \frac{n_i}{1} < 2$, there exists a quadrilateral $P = P_1 P_2 P_3 P_4$ in the hyperbolic plane $H^2$ with the interior angle $\frac{n_i}{\pi}$ at $P_i$. Let $\Gamma \subset Isom(H^2)$ be the (discrete) group generated by reflections in each side of $P$. Then the quotient space $H^2/\gamma$ is a differentiable orbifold of type $(^* n_1 n_2 n_3 n_4)$. It will be shown that the deformation space of $Rp^2$-structures on this orbifold can be mapped continuously and bijectively onto the cell of dimension 4 - \left$\mid$ {i$\mid$n_i = 2} \right$\mid$$.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.7
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• pp.1158-1168
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• 2022

In this study, the specialized marine industry in the area (Incheon) of the case study was identified and the issues related to the current status of marine space utilization were diagnosed. Marine space utilization was selected as the specialized marine industry activity in Incheon through the location quotient index analysis of the marine industry in the target area. A case review of the Yeongheungdo demonstration area and diagnosis of issues in the marine energy development sector with the lowest degree of specialization was conducted, to solve field problems such as overlapping problems in marine-use zones and civil complaints between stakeholders. It was concluded that it is necessary to prepare a policy decision support system based on objective and quantitative grounds.

• Honam Mathematical Journal
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• v.39 no.4
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• pp.575-590
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• 2017

A new class of functions called $R_{\theta}$-supercontinuous functions is introduced. Their basic properties are studied and their place in the hierarchy of strong variants of continuity, which already exist in the literature, is elaborated. The class of $R_{\theta}$-supercontinuous functions properly contains the class of $R_z$-supercontinuous functions [39] which in turn properly contains the class of $R_{cl}$-supercontinuous functions [43] and so includes all cl-supercontinuous (clopen continuous) functions ([38], [34]) and is properly contained in the class of $R_{\delta}$-supercontinuous functions [24].

• Journal of the Korean Mathematical Society
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• v.33 no.3
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• pp.625-639
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• 1996

A convex $RP^n$-structure on a smooth anifold M is a representation of M as a quotient of a convex domain $\Omega \subset RP^n$ by a discrete group $\Gamma$ of collineations of $RP^n$ acting properly on $\Omega$. When M is a closed surface of genus g > 1, then the equivalence classes of such structures form a moduli space $B(M)$ homeomorphic to an open cell of dimension 16(g-1) (Goldman [2]). This cell contains the Teichmuller space $T(M)$ of M and it is of interest to know what of the rich geometric structure extends to $B(M)$. In [3], a symplectic structure on $B(M)$ is defined, which extends the symplectic structure on $T(M)$ defined by the Weil-Petersson Kahler form.

• Bulletin of the Korean Mathematical Society
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• v.49 no.6
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• pp.1275-1289
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• 2012

In this manuscript we solve in the positive a question informally proposed by Enflo on the measure of the set of isometric reflection vectors in non-Hilbert 2-dimensional real Banach spaces. We also reformulate equivalently the separable quotient problem in terms of isometric reflection vectors. Finally, we give a new and easy example of a real Banach space whose dual has a non-trivial L-summand that does not come from an M-ideal in the predual.

• Journal of the Korean Mathematical Society
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• v.55 no.3
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• pp.695-704
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• 2018

In this paper we derive some basic inequalities connecting the Minkowski measure of symmetry, the Minkowski symmetral and the Banach-Mazur distance. We then explore the geometric contents of these inequalities and shed light on the structure of the quotient 𝔅/Aff of the space of convex bodies modulo the affine transformations.

• Journal of the Korean Mathematical Society
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• v.61 no.3
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• pp.515-545
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• 2024

Consider a Noetherian domain R₀ with quotient field K₀. Let K be a finitely generated regular transcendental field extension of K₀. We construct a Noetherian domain R with Quot(R) = K that contains R₀ and embed Spec(R₀) into Spec(R). Then, we prove that key properties of abelian varieties and smooth geometrically integral projective curves over K are preserved under reduction modulo p for "almost all" p ∈ Spec(R₀).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.12A
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• pp.1340-1348
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• 2004

In this paper, we propose a PAPR-minimized sequence mapping scheme that achieves the minimum Peak-to-Average Power Ratio (PAPR) and the minimum amount of computations for the OFDM system. To reduce the PAPR, the mapping table is created with information about block index and symbol patterns of the lower signal power. When the input data sequence comes, it performed division by the block length to find the quotient and remainder. The symbol pattern of the lower signal power can be found in terms of the block index as the quotient in the mapping table and transmitted with remainder as the side information to distinguish and recover the original data sequence in the receiver. The two methods with the proposed mapping scheme are proposed in this paper. One is with mapping table to recover the O%M signal in both transmitter and receiver. The other is with mapping table only in transmitter to reduce the load and the complexity in the mobile system. We show that this algorithm provides the PAPR reduction, the simple processing and less computational complexity to be implemented for the multi-carrier system.