• 호남수학학술지
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• 제27권3호
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• pp.389-397
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• 2005

Let K be an absolutely real abelian number field with $G=Gal(K/{\mathbb{Q}})$. Let E be a subfield of K and ${\Delta}=Gal(K/E)$. Let $C_K$ and $C_E$ be the group of circular units of K and E respectively. In [G], Greither has shown that if G is cyclic then $C_K^{\Delta}=C_E$. In this paper we show that the same result holds in function field case.

• 대한수학회논문집
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• 제33권2호
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• pp.515-525
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• 2018

In this paper, we investigate a modified $G^2$ transform on a class of Boehmians. We prove the axioms which are necessary for establishing the $G^2$ class of Boehmians. Addition, scalar multiplication, convolution, differentiation and convergence in the derived spaces have been defined. The extended $G^2$ transform of a Boehmian is given as a one-to-one onto mapping that is continuous with respect to certain convergence in the defined spaces. The inverse problem is also discussed.

• International Journal of Advanced Culture Technology
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• 제6권3호
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• pp.44-52
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• 2018

The purpose of this study was to assess the effects and find the correlation of LOTCA-G and SS-QOL on the cognitive function and quality of life of elderly stroke patients. The time period of the experiment was from March 1, 2018 to March 30, 2018, and the study sample was composed of 102 stroke out-patients who participated in the rehabilitation center in G-city and received treatment of LOTCA-G and SS-QOL. The raw scores of the cognitive function of the elderly stroke patients varied depending on their gender, age, education, and marital status, but the differences were not statistically significant. Second, the raw scores of the quality of life of the elderly stroke patients varied depending on their gender, age, education, and marital status, but only marital status showed significance (p <0.01). The elderly stroke patients' cognitive function and the quality of life showed a statistically significant correlation (p <0.01). LOTCA-G and SS-QOL generally showed significant correlation even among sub-categories, but energy, one of the sub-categories of quality of life, did not show significant correlation with any of the other sub-categories of cognitive function. By combining the study results, it was possible to see that there were high levels of correlation between cognitive function and quality of life in elderly stroke patients shown through LOTCA-G and SS-QOL. Based on this study, if the raw scores of cognitive function and quality of life could be validated and various basic data could be provided for increasing quality of life, it can be considered that the stroke patients' quality of life will be improved.

• 대한수학회보
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• 제37권2호
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• pp.229-247
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• 2000

This paper is concerned with the impulsive Cauchy problem where the control function u is a possibly discontinuous vector-valued function with finite total variation. We assume that the vector fields f, $g_i$(i=1,…, m) are dependent on the time variable. The impulsive Cauchy problem is of the form x(t)=f(t,x) +$\SUMg_i(t,x)u_i(t)$, $t\in$[0,T], x(0)=$\in\; R^n$, where the vector fields f, $g_i$ : $\mathbb{R}\; \times\; \mathbb{R}\; \longrightarrow\; \mathbb(R)^n$ are measurable in t and Lipschitz continuous in x, If $g_i's$ satisfy a condition that $\SUM{\mid}g_i(t_2,x){\mid}{\leq}{\phi}$ $\forallt_1\; <\; t-2,x\; {\epsilon}\;\mathbb{R}^n$ for some increasing function $\phi$, then the imput-output function can be continuously extended to measurable functions of bounded variation.

• 충청수학회지
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• 제9권1호
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• pp.77-87
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• 1996

For any map $v:X{\rightarrow}Y$, the generalized Gottlieb set $G({\Sigma}A;X,v,Y)$ with respect to v is a subgroup of $[{\Sigma}A,Y]$. If $v:X{\rightarrow}Y$ has a left homotopy inverse $u:X{\rightarrow}Y$, then for any $f{\in}G({\Sigma}A;X,v,Y)$, $g{\in}G({\Sigma}A;X,u,Y)$, the function spaces $L({\Sigma}A,X;uf)$ and $L({\Sigma}A,X;g)$ have the same homotopy type.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제4권1호
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• pp.27-33
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• 1997

Let (M = B$\times$f F, g) be an ($n \geq3$ )-dimensional differential manifold with Riemannian metric g. We solve the following elliptic nonlinear partial differential equation (equation omitted). where $\Delta_{g}$ is the Laplacian in the $\Delta$g-metric and ($h(\chi)$) is the scalar curvature of g and ($H(\chi)$) is a function on M.

• 대한수학회지
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• 제48권3호
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• pp.551-563
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• 2011

Let ${\kappa}$ be a positive integer and let G be a simple graph with vertex set V(G). A function f : V (G) ${\rightarrow}$ {-1, 1} is called a signed total ${\kappa}$-dominating function if ${\sum}_{u{\in}N({\upsilon})}f(u){\geq}{\kappa}$ for each vertex ${\upsilon}{\in}V(G)$. A set ${f_1,f_2,{\ldots},f_d}$ of signed total ${\kappa}$-dominating functions of G with the property that ${\sum}^d_{i=1}f_i({\upsilon}){\leq}1$ for each ${\upsilon}{\in}V(G)$, is called a signed total ${\kappa}$-dominating family (of functions) of G. The maximum number of functions in a signed total ${\kappa}$-dominating family of G is the signed total k-domatic number of G, denoted by $d^t_{kS}$(G). In this note we initiate the study of the signed total k-domatic numbers of graphs and present some sharp upper bounds for this parameter. We also determine the signed total signed total ${\kappa}$-domatic numbers of complete graphs and complete bipartite graphs.

• 한국전자파학회논문지
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• 제16권7호
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• pp.697-708
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• 2005

3G CDMA 시스템의 순방향 링크는 사용자 수의 증가에 따른 제한을 받게 된다. 기존의 채널 구분을 위한 부호인 Walsh 부호는 많은 사용자에 대 한 충분한 크기를 갖지 못하므로, Walsh 부호와 최적의 상관 특성을 갖는 준직교 부호(QOF: Quasi Orthogonal Function)가 고려되고 있다. 본 논문에서는 3G CDMA 시스템에서 더 낮은 상관 값과 우수한 성능을 갖는 재킷 행렬 상에서의 준직교 수열 생성에 관해 고찰하였다. 또한 QOF CDMA 시스템의 검파기의 단순화 및 BER 성능 개선을 위한 새로운 검파 구조를 제시하였다. 마지막으로, QOF 마스크 함수를 위한 bent 수열의 간단한 반복 생성에 대해 고찰하였다.

• 대한수학회논문집
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• 제34권1호
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• pp.55-82
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• 2019

Given ${\sigma}:G{\rightarrow}G$ an involutive automorphism of a semigroup G, we study the solutions and stability of the following functional equations $$f(x{\sigma}(y))=f(x)g(y)+g(x)f(y),\;x,y{\in}G,\\f(x{\sigma}(y))=f(x)f(y)-g(x)g(y),\;x,y{\in}G$$ and $$f(x{\sigma}(y))=f(x)g(y)-g(x)f(y),\;x,y{\in}G$$, from the theory of trigonometric functional equations. (1) We determine the solutions when G is a semigroup generated by its squares. (2) We obtain the stability results for these equations, when G is an amenable group.

• 한국통신학회논문지
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• 제27권4A호
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• pp.291-300
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• 2002

본 논문에서는 우리나라 128 비트 블록 암호 알고리즘 표준인 SEED와 유사한 구조를 가지는 암호방식에서 최적화한 S 박스와 G 함수를 구성하는 방식을 제안한다. S 박스는 비선형 함수와 아편변환으로 구성한다. 비선형함수는 차분공격과 선형공격에 강한 특성을 가지며, '0'과 '1'을 제외하고 입력과 출력이 같은 고정점과 출력이 입력의 1의 보수가 되는 역고정점을 가지지 않는 GF(2$^{8}$ ) 상의 역수로 구성한다. 아핀변환은 입력과 출력간의 상관을 최저로 하면서 고정점과 역고정점이 없도록 구성한다. G 함수는 4개의 S 박스 출력을 GF(2$_{8}$ ) 상의 4$\times$4 행렬식을 사용하여 확산선형변환한다. G 함수는 MDS(Maximum Distance Separable) 코드를 생성하구 SAC(Strict Avalanche Criterion)를 만족하고, 고정점과 역고정점 및 출력이 입력의 2의 보수가 되는 약한 입력이 없으며, 하드웨어 구현이 용이하도록 구성한다. 본 논문에서 제안한 S 박스와 G 함수는 차분공격과 선형공격에 강하고, 약한 입력이 없으며, 하드웨어 구현이 용이하며, 확산 특성이 우수하므로 안전성이 높은 암호 방식의 구성 요소로 활용할 수 있다.