• 충청수학회지
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• 제27권2호
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• pp.205-210
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• 2014

The author with C. H. Kim and Y. Lee constructed infinite families of elliptic curves over cubic number fields K with prescribed torsion groups which occur infinitely often. In this paper, we examine the Galois structures of such cubic number fields K for the families of elliptic curves with cyclic torsion.

• Journal of applied mathematics & informatics
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• 제28권1_2호
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• pp.363-372
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• 2010

In this paper we prove the almost sure convergence of partial sums of identically distributed and negatively associated random variables with infinite expectations. Some results in Kruglov[Kruglov, V., 2008 Statist. Probab. Lett. 78(7) 890-895] are considered in the case of negatively associated random variables.

• Kyungpook Mathematical Journal
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• 제46권2호
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• pp.169-180
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• 2006

This paper proves the following results: Let $f$ be a transcendental entire function, and let $k({\geq})2$ be a positive integer. If $T(r,\;f){\neq}N_{1)}(r,1/f)+S(r,\;f)$, then $ff^{(k)}$ assumes every finite nonzero value infinitely often. Also the case when f is a transcendental meromorphic function has been considered and some results are obtained.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(5)
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• pp.17-20
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• 2002

This paper describes the synthesis of robust and non-fragile Η$^{\infty}$ output feedback controller for parameter uncertain systems with time delay. The sufficient condition of controller existence, and the design method of robust and non-fragile Η$^{\infty}$ output feedback controller are presented. The obtained conditions can be represented as parameterized LMIs, and PLMIs feasibility problems involve infinitely many LMIs hence are very hard to solve. Therefore, PLMIs are replaced by a finite set of LMIs using relaxation techniques(separated convexity concepts). This method is potentially conservative but often provide practically exploitable solutions of difficult problems with a reasonable computational effort. The compatibility of resulting controller is illustrated by numerical example.

• Journal of Power Electronics
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• 제18권6호
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• pp.1844-1854
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• 2018

Isolated power systems (IPS) are often characterized by a weak grid due to small power grids. The grid side voltage is no longer equivalent to an ideal voltage source of an infinitely big power grid. The conversion control of new energy sources, parameter perturbations as well as the load itself can easily cause the system voltage to oscillate or to become unstable. To solve this problem, increasing the energy-storage power sources is usually used to improve the reliability of a system. In order to provide support for the voltage, the energy-storage power source inverter needs an method to control the voltage source. Therefore, this paper has proposed the active damping control of a voltage source inverter (VSI) based on virtual compensation. By simplifying the VSI double closed-loop control, two feedback compensation channels have been constructed to reduce the VSI output impedance without changing the characteristics of the voltage gain of a system. This improvement allows systems to operate stably in a larger range. A frequency-domain analysis, and simulation and experimental results demonstrate the feasibility and effectiveness of the proposed method.

• Structural Engineering and Mechanics
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• 제28권1호
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• pp.107-127
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• 2008

Wind turbine blades are increasing in magnitude without a proportional increase of stiffness for which reason geometrical and inertial nonlinearities become increasingly important. Often these effects are analysed using a nonlinear truncated expansion in undamped fixed base mode shapes of a blade, modelling geometrical and inertial nonlinear couplings in the fundamental flap and edge direction. The purpose of this article is to examine the applicability of such a reduced-degree-of-freedom model in predicting the nonlinear response and stability of a blade by comparison to a full model based on a nonlinear co-rotating FE formulation. By use of the reduced-degree-of-freedom model it is shown that under strong resonance excitation of the fundamental flap or edge modes, significant energy is transferred to higher modes due to parametric or nonlinear coupling terms, which influence the response and stability conditions. It is demonstrated that the response predicted by such models in some cases becomes instable or chaotic. However, as a consequence of the energy flow the stability is increased and the tendency of chaotic vibrations is reduced as the number of modes are increased. The FE model representing the case of infinitely many included modes, is shown to predict stable and ordered response for all considered parameters. Further, the analysis shows that the reduced-degree-of-freedom model of relatively low order overestimates the response near resonance peaks, which is a consequence of the small number of included modes. The qualitative erratic response and stability prediction of the reduced order models take place at frequencies slightly above normal operation. However, for normal operation of the wind turbine without resonance excitation 4 modes in the reduced-degree-of-freedom model perform acceptable.

• 트랜스-
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• 제11권
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• pp.65-95
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• 2021

서양 예술에서 이성적이고 고전적인 순정미(純精美)에 반발하기 위한 돌파구의 일종으로 종종 등장하였던 그로테스크(Grotesque)는 현대 예술에서 자주 목격된다. 그리고 그로테스크는 추(醜)라는 개념과 더불어 문화, 예술 그리고 사회 전반적인 층위에서 무한히 확장된 형태로 나타난다. 특히 신체의 탈형식화와 탈정형화를 통한 변용된 신체 이미지는 정형화된 미를 탈피하고자하는 강력한 거부로 해석된다. 본 연구는 디미트리스 파파이오아누의 작품에 나타난 신체의 변형과 왜곡, 그리고 결합을 통해 재생산된 신체가 그로테스크 범주 안에서 어떻게 해석될 수 있는지에 주된 목적을 가진다. 이를 위해 작품 해석의 근거가 되는 그로테스크 담론과 현대적 의미를 살펴보고, 그의 작품에 적용함으로써 현재 무용계에서 활발하게 논의되고 있는 분열되고 확장되는 신체가 그로테스크와 어떻게 상호 관계를 갖는지 규명한다. 신체의 왜곡과 변형이 주요한 작동 요소로 나타난 , , , 를 분석 대상으로 선정하고 그로테스크의 주된 속성인 익숙함과 낯섦, 삶과 죽음, 미(美)와 추, 혐오와 매혹 등 서로 양립된 의미를 충돌시키는 것에 중점을 두고 고찰한다. 이를 근거로 컨템포러리 무용에서 신체 부위의 해체와 임의적인 결합을 통해 재구성된 신체가 비현실적인 허구의 세계를 표현하는 것이 아닌 은폐된 것들을 드러내고, 기존의 미적 시각을 재고하게 할 뿐만 아니라 경계를 넘어서는 새로운 가능성을 모색하고 있음을 확인하고자 한다.