• Korean Journal of Mathematics
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• 제26권1호
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• pp.103-127
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• 2018

This paper is dedicated to studying some Hausdorff operators on the Heisenberg group ${\mathbb{H}}^n$. The sharp bounds on the strong-type weighted Lorentz spaces ${\Lambda}^p_u(w)$ and the weak-type weighted Lorentz spaces ${\Lambda}^{p,{\infty}}_u(w)$ are investigated. Especially, the results cover the classical power weighted space $L^{p,q}_{\alpha}$. The results are also extended to the product spaces ${\Lambda}^{p_1}_{u_1}(w_1){\times}{\Lambda}^{p_2}_{u_2}(w_2)$, especially for $L^{p_1,q_1}_{{\alpha}_1}{\times}L^{p_2,q_2}_{{\alpha}_2}$. Our proofs are quite different from those in previous documents since the duality principle, and some well-known inequalities concerning the weights are adopted. The results recover the existing results as well as we obtain new results in the new and old settings.

• 한국심리학회지 : 문화 및 사회문제
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• 제12권3호
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• pp.49-68
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• 2006

본 연구는 한국인의 가치구조와 행동판단에서의 이중성을 대학생, 성인 및 탈북자를 중심으로 알아보고자 했다. 이를 위해 대학생 150명(남: 89명, 여: 61명)과 40세 이상 성인 155명(남: 80명, 여: 75명) 그리고 남한 사회에서의 직접적인 일상생활 경험이 없는 탈북자 80명(남: 39명, 여: 41명)에게 설문을 실시하였다. 참가자들은 한국의 전통적 특성 7개 차원 및 이에 대응하는 서구적 특성 7개 차원에서 자신의 가치관, 자신의 행동 및 타인의 행동(대학생과 성인은 남한사람의 행동 그리고 탈북자는 북한사람의 행동)을 평가하였다. 그 결과, 탈북자, 성인 그리고 대학생 순으로 전통적 가치를 더 많이 가지고 있었으며, 서구적 가치는 서로 차이가 없는 대학생과 탈북자집단보다 성인에게 더 적었다. 또한, 탈북자의 가치구조가 서로 차이가 없는 대학생과 성인집단보다 더 이중적이었다. 행동판단에서의 이중성과 관련해서, 개인주의-집단주의 차원에서 세 집단 모두 타인의 행동보다 자신의 행동을 더 높게 평가했는데, 이것은 수평적 집단주의와 수평적 개인주의에서 자신들을 더 높게 평가했기 때문이다. 또한, 나머지 평가차원에서 이 세 집단 모두 타인의 행동을 자신의 행동보다 훨씬 더 부정적으로 평가했다. 이러한 결과들을 한국사회의 문화적 변동과 관련해서 논의하였다.

• 대한수학회보
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• 제37권1호
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• pp.153-169
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• 2000

Let E be a real q-uniformly smooth Banach space which admits a weakly sequentially continuous duality map, and K a nonempty closed convex subset of E. Let T : K -> K be a mapping such that $F(T)\;=\;{x\;{\in}\;K\;:\;Tx\;=\;x}\;{\neq}\;0$ and (I - T) satisfies the accretive-type condition: $\;{\geq}\;{\lambda}$\mid$$\mid$x-Tx$\mid$$\mid$^2$, for all $x\;{\in}\;K,\;x^*\;{\in}\;F(T)$ and for some ${\lambda}\;>\;0$. The weak and strong convergence of the Ishikawa iteration method to a fixed point of T are investigated. An application of our results to the approximation of a solution of a certain linear operator equation is also given. Our results extend several important known results from the Mann iteration method to the Ishikawa iteration method. In particular, our results resolve in the affirmative an open problem posed by Naimpally and Singh (J. Math. Anal. Appl. 96 (1983), 437-446).

• Korean Journal of Mathematics
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• 제24권3호
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• pp.409-445
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• 2016

The class $\mathcal{W}^{\delta}_{\beta}({\alpha},{\gamma})$ defined in the domain ${\mid}z{\mid}$ < 1 satisfying $Re\;e^{i{\phi}}\((1-{\alpha}+2{\gamma})(f/z)^{\delta}+\({\alpha}-3{\gamma}+{\gamma}\[1-1/{\delta})(zf^{\prime}/f)+1/{\delta}\(1+zf^{\prime\prime}/f^{\prime}\)\]\)(f/z)^{\delta}(zf^{\prime}/f)-{\beta}\)$ > 0, with the conditions ${\alpha}{\geq}0$, ${\beta}$ < 1, ${\gamma}{\geq}0$, ${\delta}$ > 0 and ${\phi}{\in}{\mathbb{R}}$ generalizes a particular case of the largest subclass of univalent functions, namely the class of $Bazilevi{\check{c}}$ functions. Moreover, for 0 < ${\delta}{\leq}{\frac{1}{(1-{\zeta})}}$, $0{\leq}{\zeta}$ < 1, the class $C_{\delta}({\zeta})$ be the subclass of normalized analytic functions such that $Re(1/{\delta}(1+zf^{\prime\prime}/f^{\prime})+1-1/{\delta})(zf^{\prime}/f))$ > ${\zeta}$, ${\mid}z{\mid}$<1. In the present work, the sucient conditions on ${\lambda}(t)$ are investigated, so that the non-linear integral transform $V^{\delta}_{\lambda}(f)(z)=\({\large{\int}_{0}^{1}}{\lambda}(t)(f(tz)/t)^{\delta}dt\)^{1/{\delta}}$, ${\mid}z{\mid}$ < 1, carries the fuctions from $\mathcal{W}^{\delta}_{\beta}({\alpha},{\gamma})$ into $C_{\delta}({\zeta})$. Several interesting applications are provided for special choices of ${\lambda}(t)$. These results are useful in the attempt to generalize the two most important extremal problems in this direction using duality techniques and provide scope for further research.

• 한국정보통신학회논문지
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• 제24권8호
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• pp.1022-1029
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• 2020

다중 엑세스 포인트 환경에서 전송전력과 최적의 엑세스 포인트를 선택하는 문제를 연구한다. 본 연구는 지난 연구결과를 확장하여 TA 링크와 AT 링크에서 전송전력과 엑세스 포인트를 함께 최적화한다. 목적은 모든 단말이 요구하는 최소의 신호대 간섭비를 유지하면서, 총 전송전력을 최소화하는 것이다. TA 링크와 AT 링크 모두에서 제안하는 반복적 기법을 통해서 최적화된 결과값에 수렴함을 증명한다. 실험결과를 통해 1) 전송전력과 엑세스 포인트를 동시에 최적화하는 방법이 전송전력만을 최적화하는 방법보다 전송전력 소모에 이득이 있음을 확인하였다. 또한, 2) 다중 엑세스 포인트 환경에서는 TA 링크와 AT 링크에서의 알고리즘의 결과값인 전송전력 벡터와 엑세스 포인트 벡터는 쌍대성이 성립하지 않음을 확인하였다.

• Journal of applied mathematics & informatics
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• 제27권1_2호
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• pp.59-68
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• 2009

In this paper we present an iterative scheme for finding a common element of the set of zero points of accretive mappings and the set of fixed points of nonexpansive mappings in Banach spaces. By using viscosity approximation methods and under suitable conditions, some strong convergence theorems for approximating to this common elements are proved. The results presented in the paper improve and extend the corresponding results of Kim and Xu [Nonlinear Anal. TMA 61 (2005), 51-60], Xu [J. Math. Anal. Appl., 314 (2006), 631-643] and some others.

• Journal of applied mathematics & informatics
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• 제27권1_2호
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• pp.13-23
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• 2009

Some strong convergence theorems of explicit iteration scheme for asymptotically nonexpansive semi-groups in Banach spaces are established. The results presented in this paper extend and improve some recent results in [T. Suzuki. On strong convergence to common fixed points of nonexpansive semigroups in Hilbert spaces, Proc. Amer. Math. Soc. 131(2002)2133-2136; H. K. Xu. A strong convergence theorem for contraction semigroups in Banach spaces, Bull. Aust. Math. Soc. 72(2005)371-379; N. Shioji and W. Takahashi. Strong convergence theorems for continuous semigroups in Banach spaces, Math. Japonica. 1(1999)57-66; T. Shimizu and W. Takahashi. Strong convergence to common fixed points of families of nonexpansive mappings, J. Math. Anal. Appl. 211(1997)71-83; N. Shioji and W. Takahashi. Strong convergence theorems for asymptotically nonexpansive mappings in Hilbert spaces, Nonlinear Anal. TMA, 34(1998)87-99; H. K. Xu. Approximations to fixed points of contraction semigroups in Hilbert space, Numer. Funct. Anal. Optim. 19(1998), 157-163.]

• 한국경영과학회지
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• 제28권1호
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• pp.79-95
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• 2003

This paper investigates how the weights of performance measures vary depending on corporate life cycle, such as birth, growth, maturity, revival, and decline. Balanced Scorecard performance measures are employed for this investigation. Balanced Scorecard has been widely used for measuring a corporate Performance by incorporating financial and non-financial measures simultaneously. Because these performance measures are related to the compensation and promotion of employees, research of weights of performance measures would be instrumental. Questionnaires from 218 companies are analyzed. Depending on the corporate life cycle, our survey results demonstrate that the weights of the business Performance measures differ In the four Perspectives - financial. customer, Internal Process, and learning/growth. Our results can be used for enhancing the Duality of performance measurement systems.

• Journal of applied mathematics & informatics
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• 제14권1_2호
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• pp.397-403
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• 2004

Cutler showed some duality results about Hausdorff and packing dimensions of a measure on a compact set in Euclidean space if its s-dimensional Hausdorff measure or packing measure is positive. We show that the similar results in a perturbed Cantor set hold according to its quasi s-dimensional Hausdorff measure or packing measure and we find concrete measures in this case while Cutler showed the existence of such measures. Finally under some strong condition, we give a concrete measure whose Hausdorff and packing dimensions are the same as those of the perturbed Cantor set without the condition that it has positive s-dimensional Hausdorff or packing measures.

• 소음진동
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• 제10권6호
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• pp.1017-1021
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• 2000

This paper addresses experimental results carried out to investigate the characteristics of dynamic mass for Korean. Vertical seat vibration in the frequency range of 0.5-30 Hz was applied to a seated Korean male subject. To examine the intra-variable effects on dynamic mass, five different postures and three different vibration excitation levels were considered. The applied acceleration and transmitted force to the hip of the seated subject were measured simultaneously. Detailed experimental results of measured dynamic mass are illustrated for each posture and/or vibration excitation level. Maximum peaks of around 5 Hz were observed for most experimental cases. They are found to allow the identification of dynamic characteristics of Korean seated body for various real vibration environments. Furthermore, they are expected to be very useful in designing new seats for automotive and railway vehicles and in improving their vibration ride duality.