• Korean Journal of Mathematics
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• 제26권1호
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• pp.9-21
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• 2018

We investigate existence and multiplicity of the solutions for elliptic boundary value problem with two singularities. We obtain one theorem which shows that there exists at least one nontrivial weak solution under some conditions on which the corresponding functional of the problem satisfies the Palais-Smale condition. We obtain this result by variational method and critical point theory.

• Journal of applied mathematics & informatics
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• 제36권5_6호
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• pp.491-504
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• 2018

In this article, we consider a fourth order nonlinear difference system. By making use of the critical point theory, we obtain some new existence theorems of at least one periodic solution with minimal period. Our main approach used in this article is the variational technique and the Saddle Point Theorem.

• Korean Journal of Mathematics
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• 제20권3호
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• pp.333-341
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• 2012

We investigate the number of solutions for the superlinear elliptic bifurcation problem with Dirichlet boundary condition. We get a theorem which shows the existence of at least $k$ weak solutions for the superlinear elliptic bifurcation problem with boundary value condition. We obtain this result by using the critical point theory induced from invariant linear subspace and the invariant functional.

• Korean Journal of Mathematics
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• 제21권1호
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• pp.81-90
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• 2013

We investigate the bounded weak solutions for the Hamiltonian system with bounded nonlinearity decaying at the origin and periodic condition. We get a theorem which shows the existence of the bounded weak periodic solution for this system. We obtain this result by using variational method, critical point theory for indefinite functional.

• 충청수학회지
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• 제27권4호
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• pp.707-720
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• 2014

We get a theorem which shows the existence of at least three solutions for some elliptic system with Dirichlet boundary condition. We obtain this result by using the finite dimensional reduction method which reduces the infinite dimensional problem to the finite dimensional one. We also use the critical point theory on the reduced finite dimensioal subspace.

• 호남수학학술지
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• 제30권3호
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• pp.443-468
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• 2008

We give a theorem of existence of six nontrivial solutions of the nonlinear Hamiltonian system $\.{z}$ = $J(H_z(t,z))$. For the proof of the theorem we use the critical point theory induced from the limit relative category of the torus with three holes and the finite dimensional reduction method.

• Journal of applied mathematics & informatics
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• 제37권5_6호
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• pp.399-410
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• 2019

In the manuscript, we concern with the existence of solutions of boundary value problems for fourth order nonlinear discrete systems. Some criteria for the existence of at least one nontrivial solution of the problem are obtained. The proof is mainly based upon the variational method and critical point theory. An example is presented to illustrate the main result.

• 한국응용과학기술학회지
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• 제23권3호
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• pp.185-191
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• 2006

It is desirable to have an accurate expression on the temperature dependence of surface(or interfacial) tension ${\sigma}$, because most of the interfacial thermodynamic functions can be derived from it. There have been proposed several equations on the temperature dependence of the surface tension, ${\sigma}(T)$. Among them $E{\ddot{o}}tv{\ddot{o}}s$ equation and the one modified by Katayama, which is called Katayama equation, for improving accuracies of $E{\ddot{o}}tv{\ddot{o}}s$ equation close to critical points, have been most well-known. In this article Katayama equation is interpreted on the basis of the cell model to understand the nature of the equation. The cell model results in an expression very similar to Katayama equation. This implies that, although $E{\ddot{o}}tv{\ddot{o}}s$ and Katayama equations were obtained on the basis of experimental results, they have a sound theoretical background. The Katayama equation is also modified with the phase volume replaced with a critical scaling expression. The modified Katayama equation becomes a power-law equation with the exponent slightly different from the value obtained by critical-scaling theory. This implies that Katayama equation can be replaced by a critical-scaling equation which is proven to be accurate.

• 한국철도학회:학술대회논문집
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• 한국철도학회 1998년도 추계학술대회 논문집
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• pp.313-320
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• 1998

The critical speed of a train running on the straight railway track is investigated by in-house program. The program is developed to find out nonlinear critical speed and it bases on the bifurcation theory. As a result, it is found that nonlinear critical speed exists on the lower speed band than linear critical speed and this fact imply a possibility of induction of a big accident.

• 한국언론정보학보
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• 제30권
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• pp.89-119
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• 2005

PR커뮤니케이션이 기능주의적인 시각에서 벗어나서 다양한 패러다임 접근을 받아들이는 것은 하버마스의 사회비판이론이 도구적인 이성에서 벗어나 광범위한 의사소통 합리성을 추구하는 것과 유사한 맥락에서 이해될 수 있다. 기능주의 함정으로부터 하버마스가 광범위한 합리성 통합을 통해 해답을 찾는 것과 다양한 패러다임의 통합을 통한 'PR커뮤니케이션 민주주의'의 추구는 많은 유사성을 가지고 있다. 이 연구의 목적은 도구적 이성의 왜곡화로 인해 발생하는 현대사회의 병폐를 치유하기 위한 하버마스의 의사소통합리성 기획이 어떤 면에서 PR커뮤니케이션 이론의 패러다임 변화와 맞닿아 있는가를 밝히고, 그러한 두 분야의 유사성으로부터 새로운 PR커뮤니케이션 이론화의 가능성을 모색해 보는 것이다. 또한, PR커뮤니케이션을 통해서 하버마스 사회비판이론의 실천적인 측면을 탐색해 볼 수 있으며, 개인, 조직, 국가차원의 다양한 관계 속에서 대화의 진작, 사회 합의의 도출, 갈등의 해결, 공론 장의 확대와 같은 포괄적인 커뮤니케이션 합리성을 적용해 보는 계기를 마련해 볼 수 있다.