• Journal of the Korean Mathematical Society
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• v.54 no.2
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• pp.493-506
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• 2017

In this paper, we define the modulus of n-dimensional U-flatness as the determinant of an $(n+1){\times}(n+1)$ matrix. The properties of the modulus are investigated and the relationships between this modulus and other geometric parameters of Banach spaces are studied. Some results on fixed point theory for non-expansive mappings and normal structure in Banach spaces are obtained.

• Honam Mathematical Journal
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• v.33 no.3
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• pp.381-391
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• 2011

One of the main interesting things of a matroid theory is the representability by a matroid from a matrix over some field F. The representability of uniform matroid $U_{m,n}$ over some field are studied by many authors. In this paper we construct a matrix representing $U_{3,6}$ over the field GF(4). Also we find out matrix of the affine matroid AG(2, 3) over the field GF(4).

• Honam Mathematical Journal
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• v.43 no.3
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• pp.513-522
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• 2021

In this current study, we aim to give some applications on fourth-order differential subordination for p-valent meromorphic functions in the region U^* = {z ∈ ℂ : 0 < |z| < 1} = U∖{0}, where U = {z ∈ ℂ : |z| < 1} , involving the linear operator 𝓛^*_pf. By making use of basic concepts in theory of the fourth-order, we find new outcomes.

• Bulletin of the Korean Mathematical Society
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• v.53 no.6
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• pp.1805-1821
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• 2016

In this paper, we are concerned with the nonlinear elliptic equations of the p(x)-Laplace type $$\{\begin{array}{lll}-div(a(x,{\nabla}u))+{\mid}u{\mid}^{p(x)-2}u={\lambda}f(x,u) && in\;{\Omega}\\(a(x,{\nabla}u)\frac{{\partial}u}{{\partial}n}={\lambda}{\theta}g(x,u) && on\;{\partial}{\Omega},\end{array}$$ which is subject to nonlinear Neumann boundary condition. Here the function a(x, v) is of type${\mid}v{\mid}^{p(x)-2}v$ with continuous function $p:{\bar{\Omega}}{\rightarrow}(1,{\infty})$ and the functions f, g satisfy a $Carath{\acute{e}}odory$ condition. The main purpose of this paper is to establish the existence of at least three solutions for the above problem by applying three critical points theory due to Ricceri. Furthermore, we localize three critical points interval for the given problem as applications of the theorem introduced by Arcoya and Carmona.

• Journal of Korean Medical classics
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• v.20 no.2
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• pp.25-30
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• 2007

It is well-known fact that Korean medicine is related to Taoism. Dong-$\breve{u}$ibogam(東醫寶鑑) was written by Heo-Jun(許浚) in Jo-seon(朝鮮) dynasty. Heo-Jun complied all of past studies on Korean medicine in this book. On the basis of Naegyoung(內徑), he accepted the theory of four eminent physicians of the K$\breve{u}$m and Won Dynasty(金元時代) in ancient China and Eubangyouchui(醫方類聚), $\breve{U}$irimch'waryo(醫林撮要), Hyang-yakjips$\breve{o}$ngbang(鄕藥集成方) in Jo-seon. Especially, Dong-$\breve{u}$ibogam is so characteristic of Taoism than any other medical books written in China or Korea before. In this study, I researched the relation between Dong-$\breve{u}$ibogam and Taosim on the views of authors, organization, reference hooks, contents.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.11 no.1
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• pp.13-30
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• 2007

In this paper we study the numerical solutions of the stochastic functional differential equations of the following form $$du(x,\;t)\;=\;f(x,\;t,\;u_t)dt\;+\;g(x,\;t,\;u_t)dB(t),\;t\;>\;0$$ with initial data $u(x,\;0)\;=\;u_0(x)\;=\;{\xi}\;{\in}\;L^p_{F_0}\;([-{\tau},0];\;R^n)$. Here $x\;{\in}\;R^n$, ($R^n$ is the ${\nu}\;-\;dimenional$ Euclidean space), $f\;:\;C([-{\tau},\;0];\;R^n)\;{\times}\;R^{{\nu}+1}\;{\rightarrow}\;R^n,\;g\;:\;C([-{\tau},\;0];\;R^n)\;{\times}\;R^{{\nu}+1}\;{\rightarrow}\;R^{n{\times}m},\;u(x,\;t)\;{\in}\;R^n$ for each $t,\;u_t\;=\;u(x,\;t\;+\;{\theta})\;:\;-{\tau}\;{\leq}\;{\theta}\;{\leq}\;0\;{\in}\;C([-{\tau},\;0];\;R^n)$, and B(t) is an m-dimensional Brownian motion.

• Communications of the Korean Mathematical Society
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• v.37 no.1
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• pp.137-161
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• 2022

In this article, we study the existence and multiplicity of homoclinic solutions for the following fourth-order differential equation (1) u⁽⁴⁾(x) + ωu''(x) + a(x)u(x) = f(x, u(x)), ∀x ∈ ℝ where a(x) is not required to be either positive or coercive, and F(x, u) = ∫^u₀ f(x, v)dv is of subquadratic or superquadratic growth as |u| → ∞, or satisfies only local conditions near the origin (i.e., it can be subquadratic, superquadratic or asymptotically quadratic as |u| → ∞). To the best of our knowledge, there is no result published concerning the existence and multiplicity of homoclinic solutions for (1) with our conditions. The proof is based on variational methods and critical point theory.

• Journal of the Korean Society for Railway
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• v.16 no.5
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• pp.379-385
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• 2013

In this study, partial drilled shafts (Bottom Cast-in-place Concrete pile) were applied to the pilot test site to ensure the bearing capacity; we used the skin friction force in the IGM to analyze the feasibility of the application of IGM theory. The soil characteristics were analyzed in cohesive, non-smear, and smooth conditions for the application of the IGM theory via geotechnical investigation and measurement of the disturbance and surface roughness. Static load and load transfer tests were conducted to calculate the allowable bearing capacity and the skin friction force by depth. The skin friction force increased with increase in the depth and standard settlement, showing a very high correlation. In addition, because the unconfined strength ($q_u$), which is the most important parameter in the cohesive IGM, cannot be measured in a weathered granite area, the static load and load transfer test results and the N value were used to obtain $q_u$.

• Journal of Digital Convergence
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• v.12 no.12
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• pp.217-225
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• 2014

The objective of this study is to propose the implications using theory of reasoned action(TRA) on u-Tour system. This research model through TRA is consisted as three constructs: user-friendliness(cognitive), perceived usefulness(cognitive) and purchase intention(affective). This study analyzes with a total of 153 respondents and used PLS-SEM method considering the small number of samples. Also, with the analysis, WarpPLS software is used in order to ferret out non-linear relationship between the constructs of research model. As a result of analysis, this research model shows statistical level significantly on proposed hypotheses and the applicability of TRA model in u-Tour system. Furthermore, additional analysis presents the possibility of non-linear relationship on each path between the constructs of research model showing J-shape. Also, the result showes the fact that the relationship had partly negative (-) effect on dependent factor. Additional analysis proposes that income variable as base of purchase intention has a moderating effect on all paths of research model.

• Journal of Technology Innovation
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• v.21 no.1
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• pp.109-139
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• 2013

The objective of this study attempt to examine the prospect whether conventional catch-up theory is also applicable to knowledge intensive industry like Open Source Software(OSS), and the implication from this study can be working as a stepping stone for followers. To do this, we conducted Korean SW firm's interview, and examined U.S. firm's archivings and second source of informations by means of empirical study. We use the inflection point of paradigm shift and difference of technology regime as a framework for empirical study of catch-up process between U.S. and Korean OSS firms. We find that conventional catch-up theory is no more applicable to explain OSS firm's catch-up processes. We also identified the elements that will accelerate the catch-up processes more effectively from the comparison of technology regime between U.S. and Korean OSS firms. As a result, we diagnose the limitation of conventional catch-up theory and discuss the new technology regime which will, ironically, promote the catch-up processes from the condition of low appropriation.