• Structural Engineering and Mechanics
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• 제63권4호
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• pp.439-446
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• 2017

This work proposes an original single variable shear deformation theory to study the buckling analysis of thick isotropic plates subjected to uniaxial and biaxial in-plane loads. This theory is built upon the classical plate theory (CPT) including the exponential function in terms of thickness coordinate to represent shear deformation effect and it involves only one governing differential equation. Efficacy of the present theory is confirmed through illustrative numerical examples. The obtained results are compared with those of other higher-order shear deformation plate theory results.

• Steel and Composite Structures
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• 제27권5호
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• pp.599-611
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• 2018

In this article a four unknown quasi-3D shear deformation theory for the bending analysis of functionally graded (FG) plates is developed. The advantage of this theory is that, in addition to introducing the thickness stretching impact (${\varepsilon}_z{\neq}0$), the displacement field is modeled with only four variables, which is even less than the first order shear deformation theory (FSDT). The principle of virtual work is utilized to determine the governing equations. The obtained numerical results from the proposed theory are compared with the CPT, FSDT, and other quasi-3D HSDTs.

• Steel and Composite Structures
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• 제24권5호
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• pp.569-578
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• 2017

In this research work, a simple and accurate hyperbolic plate theory for the buckling analysis of functionally graded sandwich plates is presented. The main interest of this theory is that, in addition to incorporating the thickness stretching effect (${\varepsilon}_z{\not=}0$), the displacement field is composed only of 5 unknowns as the first order shear deformation theory (FSDT), instead of 6 like in the well-known "higher order shear and normal deformation theories". Thus, the number of unknowns and governing equations for the present theory is reduced, significantly facilitating engineering analysis. Governing equations are obtained by employing the principle of minimum total potential energy. Comparison studies are performed to verify the validity of present results. A numerical investigation has been conducted considering and neglecting the thickness stretching effects on the buckling of sandwich plates with functionally graded skins. It can be concluded that the present theory is not only accurate but also simple in predicting the buckling response of sandwich plates with functionally graded skins.

• 한국연극학
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• 제40호
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• pp.307-344
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• 2010

Cultural Studies built on the critical mind of New Left exposes the relationship between culture and power, and investigates how this relationship develops the cultural convention. It has achieved the new perspective that could make us to think culture and art in terms of political correctness. However, the critical voices against the theoretical premises of Cultural Studies have been increased as its heyday in 1980s was nearly over. For instance, Terry Eagleton, a former Marxist literary critic, declared in 2003 that the golden age of cultural theory is long past. This essay, therefore, intends to show the weak foundations on which the approaches of cultural studies to theatre rest and to clarify the general problem of their introduction to theatre studies. The approach of cultural studies to theatre takes the form of 'top-down inquiry' as it applies a theory to a particular play or historical period. In other word, from the theory the writer moves to the particular case. The result is not an inquiry but rather a demonstration. This circularity can destroy the point of serious intellectual investigation as the theory dictates answers. The goal-oriented narrow viewpoint as a logical consequence of 'top-down inquiry' makes the researcher to favor the plays or the parts of a play that are proper to test a theory. As a result it loses the fair judgment on the artistic value of a play, and brings about the misinterpretation. The interpreter-oriented reading is the other defect of cultural studies as it disregards the inherent meaning of the text, distorting a play. The approach of cultural studies also consists of a conventionality as it arrives at a stereotyped interpretation by using certain conventions of reasoning and rhetoric. The cultural theories are fundamentally the 'outside theories' that seek to explain not theatre but the very broad features of society and politics. Consequently their application to theatre risks the destructive criticism, disregarding the inherent experience of theatre. Most of, if not all, cultural theories, furthermore, are proven to be lack of empirical basis. The alternative method to them is a 'cognitive science' that proves scientifically our mind being influenced by bodily experience. The application of cultural materialism to Shakespeare's is one of the cases that reveal the limits of cultural studies. Jonathan Dollimore and Water Cohen provide a kind of 'canonical study' in this application that is imitated by the succeeding researchers. As a result the interpretation of has been flooded with repetitive critical remarks, revealing the problem of 'top-down inquiry' and conventional reasoning. Cultural Studies is antipodal to theatre in some respect. It is interested chiefly in the social and political reality while theatre aims to create the fiction world. The theatre studies, therefore, may have to risk the danger of destroying its own base when it adopts cultural studies uncritically. The different stance between theatre and cultural theories also occurs from the opposition of humanism vs. antihumanism. We have to introduce cultural theories selectively and properly not to destroy the inherent experience and domain of theatre.

• 대한한의학원전학회지
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• 제10권
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• pp.591-617
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• 1997

In the field of the theory about constitution(體質), the theory of 'Yun Qi(運氣) has close relations hip with the formation of theory of constitution. It is seen in the chapter 'Osangjungdae-ron("五常政大論")' that the theory of influenced the theory of constitution and talent by the 'Concept of Evaporation(氣化)'. In the chapter 'Yin-Yang twenty five men types' of the book the 'Ling Shu("靈樞")' the twenty five constitution types by the theory of 'Yan Qi is stated. And in the book 'Nei Ching("內經")' the constitution types of five elements' motion is described. In the theory of the 'five elements' motion and six kinds of natural factors' had such a problem that the individuals having the same born year and Qi had the same prescriptions irrespective of each other's constitution. So for the resolution of this problem the constitution theory of 'Yun Qi' had been formed by the mediation of the 'MyengRiHak(命理學)' and the theory of 'Yun Qi' in the book the 'OUnYukKiHanYeHakBoGam("五運六氣韓醫學寶鑑")'. But following problems should be resolved in chrono-inedieine. Those are the difference of men who has born in some year-day-time, each 'Yun Qi's brea king point, local time, summer time, living circumstances, twins, the concept of 'Zhung Won(中元)', etc.

• Smart Structures and Systems
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• 제19권6호
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• pp.601-614
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• 2017

In this work, free vibration analysis of size-dependent functionally graded (FG) nanoplates resting on two-parameter elastic foundation is investigated based on a novel nonlocal refined trigonometric shear deformation theory for the first time. This theory includes undetermined integral variables and contains only four unknowns, with is even less than the conventional first shear deformation theory (FSDT). Mori-Tanaka model is employed to describe gradually distribution of material properties along the plate thickness. Size-dependency of nanosize FG plate is captured via the nonlocal elasticity theory of Eringen. By implementing Hamilton's principle the equations of motion are obtained for a refined four-variable shear deformation plate theory and then solved analytically. To show the accuracy of the present theory, our research results in specific cases are compared with available results in the literature and a good agreement will be demonstrated. Finally, the influence of various parameters such as nonlocal parameter, power law indexes, elastic foundation parameters, aspect ratio, and the thickness ratio on the non-dimensional frequency of rectangular FG nanoscale plates are presented and discussed in detail.

• Journal of Electrical Engineering and Technology
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• 제13권3호
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• pp.1110-1122
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• 2018

This paper proposes an alternative method to evaluate the effect of wind power to the power system stability with small disturbance. Alternatively, available techniques for stability analysis of a power system based on deterministic methods are less accurate for high penetration of wind power. Numerical simulations of random behaviors are computationally expensive. A stochastic stability index (SSI) is proposed for the power system stability evaluation based on the theory of stochastic stability and energy function, specifically the stochastic derivative of the relative well-defined energy function and the critical energy. The SSI is implemented on the modified nine-bus system including wind turbines under different conditions. A doubly-fed induction generator (DFIG) wind turbine is characterized and modeled using measured wind data from several sites in Thailand. Each of the obtained wind power data is analyzed. The wind power effect is modeled considering the aggregated effect of wind turbines. With the proposed method, the system behavior is properly predicted and the stability is quantitatively evaluated with less computational effort compared with conventional numerical simulation methods.

• 한국시조학회지:시조학논총
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• 제21집
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• pp.207-239
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• 2004

이 논문에서는 정철 시조에 나타난 현실 지향과 풍류의 성격을 논의했다. 정철은 일반 유자들이 가지는 현실지향의 근본적 성격을 바탕에 가지면서도 근기 지역의 기호 사림의 일원으로서 주기적 세계관-을 가짐으로써 더 현실지향성을 가졌고 유년에 행복한 궁중 생활을 체험함으로써 그의 현실 지향은 구체적으로는 궁중 지향으로 나타났다. 시조에서 군주와 단절된 상황일 때에 절대적 지향성을 가지고 단절을 극복하지 위한 갖가지 노력을 했고 자아의 정체성을 역설적으로 드러내어 군주를 향한 절대적 지향의 당위성을 드러냈다. 군주와 관계가 지속되는 상황에서 작자는 궁중에서의 관직 생활을 행복한 추억으로 기억하였고 지방관으로 나가 있을 때에는 현직에 복무하면서도 군주가 있는 궁중 지향을 그치지 않았다. 현실 지향성과 관련하여 자연과 음주는 정철에게 있어 풍류의 중요한 요인이 되었다. 자연과의 관계에서 정철이 군주와 긍정적인 관계를 유지할 때에는 유흥과 호방함의 정서를 드러냈고 군주와 부정적 관계 속에 처했을 때에는 자연을 통하여 자신의 결백함을 드러내거나 자연과 단절된 자신의 모습을 표현했다. 물러나 자연과 친화하며 심성을 연마하고 후진을 양성하던 일반 유자들과는 달랐다. 음주에 있어서 정철은 군주와의 우호적 관계에서는 술을 통하여 여유와 유흥을 주된 내용으로 표현했고 군주와 단절된 상황에서는 고뇌와 근심을 씻기 위하여 통음에 자신을 내맡기는 감성적 행동을 시조에 표현했다. 술을 통하여 고뇌를 이기려는 성향은 그의 스승 김인후 한시나 그의 후배인 신흠의 시조에서도 확인되어 음주 풍류의 한 전통을 형성하고 있었다.

• Smart Structures and Systems
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• 제10권2호
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• pp.111-130
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• 2012

Satellites with flexible lightweight solar panels are sensitive to vibration that is caused by internal actuators such as reaction or momentum wheels which are used to control the attitude of the satellite. Any infinitesimal amount of unbalance in the reaction wheels rotors will impose a harmonic excitation which may interact with the solar panels structure. Therefore, quenching the solar panel's vibration is of a practical importance. In the present work, the panels are modeled as laminated composite beam using first-order shear deformation laminated plate theory which accounts for rotational inertia as well as shear deformation effects. The vibration suppression is achieved by bonding patches of piezoelectric material with suitable dimensions at selected locations along the panel. These patches are actuated by driving control voltages. The governing equations for the system are formulated and the dynamic Green's functions are used to present an exact yet simple solution for the problem. A guide lines is proposed for determining the values of the driving voltage in order to suppress the induced vibration.

• 대한수학회논문집
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• 제34권1호
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• pp.333-349
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• 2019

The paper study the curvature theory of a line-trajectory of constant Disteli-axis, according to the invariants of the axodes of moving body in spatial motion. A necessary and sufficient condition for a line-trajectory to be a constant Disteli-axis is derived. From which new proofs of the Disteli's formulae and concise explicit expressions of the inflection line congruence are directly obtained. The obtained explicit equations degenerate into a quadratic form, which can easily give a clear insight into the geometric properties of a line-trajectory of constant Disteli-axis with the theory of line congruence. The degenerated cases of the Burmester lines are discussed according to dual points having specific trajectories.