• 충청수학회지
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• 제23권4호
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• pp.749-755
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• 2010

We investigate biprojectivity of $C_{r}^{*}(G)$ as a $L^1(G)$-bimodule for a locally compact group G. The main results are the following. As a $L^1(G)$-bimodule$C_{r}^{*}(G)$ is biprojective if G is compact and is not biprojective if G is an infinite discrete group or G is a non-compact abelian group.

• 호남수학학술지
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• 제22권1호
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• pp.47-52
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• 2000

We determine the Shilov and Choquet boundaries and the set of peak points of Lipschitz algebras $Lip(X,\;{\alpha})$ for $0<{\alpha}{\leq}1$, and $lip(X,\;{\alpha})$ for $0<{\alpha}<1$, on a compact metric space X. Then, when X is a compact subset of $\mathbb{C}^n$, we define some subalgebras of these Lipschitz algebras and characterize their Shilov and Choquet boundaries. Moreover, for compact plane sets X, we determine the Shilove boundary of them. We also determine the set of peak points of these subalgebras on certain compact subsets X of $\mathbb{C}^n$.

• 한국분말재료학회지
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• 제7권1호
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• pp.50-54
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• 2000

In order to reduce the sintering temperature of iron based sintered parts, sinteing properties of iron-copper prealloyed powder were investigated at various temperatures in the range of 700∼890$^{\circ}C$, and than the rusults were compared with those of the conventional iron-copper-tin compact using elemental powders, The using of prealloyed as a new process improved its sintering performance at lower temperature than elemental powder as the conventional process. The relative sintered density and radial crushing stength of the compact using prealloyed were higher than those of using elemental powder at all sintering temperature. For example, the radial curength of the compact using powder was about 50kg/mm2 at 700$^{\circ}C$, while that of the compact using elemental powder sintered at 890$^{\circ}C$ was 43kg/mm2.

• Korean Journal of Mathematics
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• 제27권4호
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• pp.949-968
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• 2019

In this work, we characterize some matrix classes concerning the Binomial sequence spaces b^r,s_∞ and b^r,s_p, where 1 ≤ p < ∞. Moreover, by using the notion of Hausdorff measure of noncompactness, we characterize the class of compact matrix operators from b^r,s₀, b^r,s_c and b^r,s_∞ into c₀, c and ℓ_∞, respectively.

• 한국통신학회논문지
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• 제31권7C호
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• pp.706-712
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• 2006

본 논문에서는 OFDM(Orthogonal Frequency Division Multiplexing) 시스템의 반송파 주파수 동기화부 구현을 위하여 Compact CORDIC 처리기를 제안한다. Compact CORDIC 처리기는 반송파 주파수 옵셋 추정 및 보상시에 요구되는 OFDM 시스템의 독특한 특성을 이용하여 제안되었으며, Compact CORDIC 전처리부와 Compact CORDIC 처리부로 구성된다. Compact CORDIC 전처리부에서는 신호의 정규화를 효율적으로 수행하며, Compact CORDIC 처리부에서는 Vector 모드 CORDIC 과 Rotation 모드 CORDIC 연산을 효율적으로 결합하여 동시에 처리하여 반송파 주파수 동기화를 수행한다. FPGA 구현을 통하여 제안된 Compact CORDIC 처리기가 기존 CORDIC 방법보다 성능이 우수하며 구현 복잡도가 크게 감소함을 확인한다.

• 산업기술연구
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• 제6권
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• pp.9-12
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• 1986

이 논문(論文)에서는 net와 연속함수(連續函數)의 족(族)에서 상(像)에 의한 Compact 공간(空間)의 성질(性質)을 조사하였다. Compact 공간(空間)에 기초를 둔 C-closed, A-net, A-변환(變換)을 사용하여 Haussdorff 공간(空間) 혹은 Regular 공간(空間)에서의 그들의 성질(性質)을 살펴보았다.

• 호남수학학술지
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• 제39권4호
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• pp.655-663
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• 2017

In this paper we define $AP_c$ and $AP_{cc}$ spaces which are stronger than the property of approximation by points(AP). We investigate operations on their subspaces and study function theorems on $AP_c$ and $AP_{cc}$ spaces. Using those results, we prove that every continuous image of a countably compact Hausdorff space with AP is AP. Finally, we prove a theorem that every compact ${\kappa}$-WAP space is ${\kappa}$-pseudoradial, and prove a theorem that the product of a compact ${\kappa}$-radial space and a compact ${\kappa}$-WAP space is a ${\kappa}$-WAP space.

• 한국분말재료학회지
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• 제15권4호
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• pp.271-278
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• 2008

Sintering behavior of iron nanopowder agglomerate compact prepared by slurry compaction method was investigated. The Fe nanopowder agglomerates were prepared by hydrogen reduction of spray dried agglomerates of ball-milled $Fe_2O_3$ nanopowder at various reduction temperatures of $450^{\circ}C$, $500^{\circ}C$ and $550^{\circ}C$, respectively. It was found that the Fe nanopowder agglomerates produced at higher reduction temperature have a higher green density compact which consists of more densified nanopowder agglomerates with coarsed nanopowders. The sintering behavior of the Fe nanopowder agglomerates strongly depended on the powder packing density in the compact and microstructure of the agglomerated nanopowder. It was discussed in terms of two sintering factors affecting the entire densification process of the compact.

• 대한수학회지
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• 제34권2호
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• pp.321-336
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• 1997

Let S be the Ricci curvature of an n-dimensional compact minimal totally real submanifold M of a quaternion projective space $HP^n (c)$ of quaternion sectional curvature c. We proved that if $S \leq \frac{16}{3(n -2)}c$, then either $S \equiv \frac{4}{n - 1}c$ (i.e. M is totally geodesic or $S \equiv \frac{16}{3(n - 2)}c$. All compact minimal totally real submanifolds of $HP^n (c)$ satisfy in $S \equiv \frac{16}{3(n - 2)}c$ are determined.

• Kyungpook Mathematical Journal
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• 제10권1호
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• pp.75-80
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• 1970