• Journal of the Korean Mathematical Society
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• v.35 no.4
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• pp.843-853
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• 1998

We establish bounds for the domination number of a digraph in terms of the minimum indegree and the order, and then we find a sharp upper bound for the domination number of a weak digraph with minimum indegree one. We also determine the domination number of a random digraph.

• Communications of the Korean Mathematical Society
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• v.10 no.1
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• pp.27-34
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• 1995

For an $n \times n$ matrix $A = [a_{ij}]$, the permanent of A, per A, is defined by $$ per(A) = \sum_{\sigma}{a_{1 \simga(1)} \cdots a_{n \sigma(n)}}, $$ where $\sigma$ runs over all permutations of ${1,\cdots,n}.

• Communications of the Korean Mathematical Society
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• v.33 no.3
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• pp.1001-1011
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• 2018

We introduce some variants of the finite Ramsey theorem. The variants are based on a refinement of homogeneity. In particular, they cover homogeneity, minimal homogeneity, end-homogeneity as special cases. We also show how to obtain upper bounds for the corresponding Ramsey numbers.

• Journal of the Korean Mathematical Society
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• v.41 no.3
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• pp.407-421
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• 2004

By using a recursive algorithm, we construct edge-coloured graphs representing products of spheres and consequently we give upper bounds for the regular genus of ${\mathbb{S}}^{m}\;\times\;{\mathbb{S}}^{n}$, for each m, n > 0.

• Communications for Statistical Applications and Methods
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• v.6 no.1
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• pp.1-10
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• 1999

When the component proportions in mixture experiments are restricted by lower and upper bounds multicollinearity appears all too frequently. The ridge regression can be used to stabilize the coefficient estimates in the fitted model. I propose a graphical method for evaluating the mixture component effects of ridge regression estimator with respect to the prediction variance and the prediction bias.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1992.04b
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• pp.14-23
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• 1992

본 논문은 스케줄링 문제등 정수계획문제에서 흔히 찾아볼 수 있는 변수상한 제약을 갖는 문제의 효율적인 해법을 위한 분석적인 틀을 마련하기 위한 연구이다. 본 연구에서는 이 문제에 관한 기존의 알고리즘적 해법과 달리 분해기법을 이용하여 일반변수상한 문제에 까지 확장 적용될 수 있음을 분석적으로 보였다.

• Korean Journal of Mathematics
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• v.18 no.2
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• pp.149-160
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• 2010

Let $W(x)={\prod}_{k=1}^m{\mid}x-x_k{\mid}^{{\gamma}_k}{\cdot}{\exp}(-{\mid}x{\mid}^{\alpha})$. Associated with the weight W, upper and lower bounds of the generalized Christoffel functions for generalized nonnegative polynomials are obtained.

• Communications of the Korean Mathematical Society
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• v.15 no.2
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• pp.379-390
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• 2000

In this paper the limit theorems on lag increments of a Wiener process due to Chen, Kong and Lin [1] are developed to the case of a Gaussian process via estimating upper bounds of large deviation probabilities on suprema of the Gaussian process.

• Journal of the Chungcheong Mathematical Society
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• v.24 no.4
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• pp.833-842
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• 2011

We prove that Toeplitz operators with symbols in RW are bounded and we calculate some upper bounds of the norm of these Toeplitz operators. We also analyze n-th derivative of Toeplitz operators and get some local estimates.

• Journal of Communications and Networks
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• v.1 no.3
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• pp.182-188
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• 1999

The optimal joint maximum-likelihood sequence estima-for using an array of antennas is derived for synchronous direct sequence-code division multiple access (DS-CDMA) system. Each user employs a rate 1/n convolutional code for channel coding for the additive white Gaussian noise (AWGN) channel. The array re-ceiver structure is composed of beamformers in the users' direc-tions followed by a bank of matched filters. The decoder is imple-mented using a Viterbi algorithm whose states depend on the num-ber of users and the constraint length of the convolutional code. The asymptotic array multiuser coding gain(AAMCG)is defined to encompass the asymptotic multiuser coding gain and the spatial information on users' locations in the system. We derive the upper and lower bounds of the AAMCG. As an example, the upper and lower bounds of AAMCG are obtained for the two user case where each user employes the maximum free distance convolutional code with rate 1/2. The enar-far resistance property is also investigated considering the number of antenna elements and user separations in the space.