• 대한기계학회논문집A
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• 제37권12호
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• pp.1547-1557
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• 2013

시간변화 이동자기력이 작용하는 레일의 변형을 티모센코 보 이론(Timoshenko beam theory)로 가정하였으며, 보의 진동특성에 영향을 미치는 탄성체기초의 감쇠효과 및 강성을 고려하였다. 푸리에 급수와 수치해석을 이용해 강제진동모델의 동적응답과 임계속도를 구하였다. 레일의 진동모델을 유한요소 해석 및 오일러 보 이론(Euler beam theory)과 비교 검증하였다. 강제진동모델을 이용하여 레일의 영구변형을 예측하였으며, 실험결과 레일표면의 영구변형 및 마모를 확인하였다. 보의 설계변수인 레일의 형상, 재료, 탄성체 기초의 감쇠효과 및 강성이 레일의 임계속도 및 레일의 처짐, 축 방향 응력, 전단 응력에 미치는 영향에 대한 매개변수적 연구를 진행하였으며, 보의 설계방향을 얻을 수 있었다.

• 유통과학연구
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• 제11권5호
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• pp.63-76
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• 2013

Purpose - For the past several decades, behavioral economics or behavioral decision theory has undergone rapid development. This study provides a critical review of the development of behavioral economics with a focus on what are deemed to be core theories in the field. Starting from the utility function proposed by Daniel Bernoulli in the 18th century, the development history of utility functions until the emergence of the prospect theory is thoroughly reviewed. Some of the experimental results violating the traditionally assumed utility function and supporting the prospect theory value function are summarized. The most representative principles of rational choice are transitivity, independence from irrelevant alternatives (IIA), and regularity. The development of behavioral economics has been triggered by finding counter-examples to these principles. Some of the choice behaviors discussed in this study as counter-examples to the traditional theories of rational choice are the St. Petersburg paradox; the Allais paradox; gambling behavior; and the various context effects including the similarity effect, attraction effect, and the compromise effect. The Elimination-by-Aspects (EBA) model, which was proposed as an explanation for the similarity effect, is discussed in detail as well. Based on the literature review and further analysis, this study summarizes the relationship between the context effects, prospect theory, and EBA model. Research design, data, and methodology - This study provides an extensive literature review on several important theories in the field of behavioral decision theory and adds some critical comments to the theories and the relationships among them. This study first reviews the development of utility functions. Daniel Bernoulli introduced the concept of utility function to solve the St. Petersburg paradox. In the mid-20th century, Herbert Simon proposed the "satisficing" heuristic and presented a value function with a shape different from traditional utility functions. This study highlights the strengths and weaknesses of several utility functions proposed until the emergence of the prospect theory value function. Results - This study posits that prospect theory and EBA model are the two most important theories in the field of behavioral decision theory. They can explain various choice behaviors that traditional utility maximization analysis has been unable to. The application of these models to various fields is further increasing nowadays. This study explains how prospect theory and the EBA model can be used to explain the context effects. Conclusions - The traditional economic theory relies on a single variable called "utility" in explaining consumer choice. However, this study argues that, in investigating consumer choice, several other variables should also be considered. These are the similarity among alternatives, an alternative's prototypicality within the category, the dominance relationship between alternatives, and the reference point in evaluating alternatives. Due to the development of behavioral economics, we are now closer to a more complete understanding of consumer choice behavior than in the past when we had only a single tool called utility.

• Structural Engineering and Mechanics
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• 제70권3호
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• pp.269-277
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• 2019

Using the non-local elasticity theory, Timoshenko beam model is developed to study the non- local buckling of Triple-walled carbon nanotubes (TWCNTs) embedded in an elastic medium under axial compression. The chirality and small scale effects are considered. The effects of the surrounding elastic medium based on a Winkler model and van der Waals' (vdW) forces between the inner and middle, also between the middle and outer nanotubes are taken into account. Considering the small-scale effects, the governing equilibrium equations are derived and the critical buckling loads under axial compression are obtained. The results show that the critical buckling load can be overestimated by the local beam model if the small-scale effect is overlooked for long nanotubes. In addition, significant dependence of the critical buckling loads on the chirality of zigzag carbon nanotube is confirmed. Furthermore, in order to estimate the impact of elastic medium on the non-local critical buckling load of TWCNTs under axial compression, the use of these findings are important in mechanical design considerations, improve and reinforcement of devices that use carbon nanotubes.

• 대한수학회지
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• 제56권5호
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• pp.1419-1439
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• 2019

In this paper, we consider a class of noncooperative fourth-order elliptic systems involving nonlocal terms and critical growth in a bounded domain. With the help of Limit Index Theory due to Li [32] combined with the concentration compactness principle, we establish the existence of infinitely many solutions for the problem under the suitable conditions on the nonlinearity. Our results significantly complement and improve some recent results on the existence of solutions for fourth-order elliptic equations and Kirchhoff type problems with critical growth.

• 대한화학회지
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• 제58권6호
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• pp.528-534
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• 2014

어떤 이성분계용액에서는 상한임계용액온도와 하한임계용액온도가 동시에 나타나는 원형모양의 온도-조성 상도를 보인다. 이러한 현상은 분자간 특정상호작용이 존재하는 경우 나타나는 것으로 알려져 있다. 특정상호작용을 묘사하는 방법에는 여러 가지가 있다. 본 연구에서는 특정상호작용의 총수가 이항분포에 따라 분포한다고 가정하였다. 이 경우 특정상호작용을 Regular 용액이론, Quasichemical 이론 그리고 Flory-Huggins 격자이론에 적용하였을 때 원형모양의 온도-조성 상도를 보이는 경우에 대한 정확한 수학적인 조건을 유도하였다. 그리고 매개변수들이 온도-조성상도에 미치는 영향을 조사하였고, 물-니코틴에 대한 온도-조성상도를 계산하여 실험값과 비교하여 보았다.

• Steel and Composite Structures
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• 제21권6호
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• pp.1347-1368
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• 2016

In this article, an exact analytical solution for mechanical buckling analysis of symmetrically cross-ply laminated plates including curvature effects is presented. The equilibrium equations are derived according to the refined nth-order shear deformation theory. The present refined nth-order shear deformation theory is based on assumption that the in-plane and transverse displacements consist of bending and shear components, in which the bending components do not contribute toward shear forces and, likewise, the shear components do not contribute toward bending moments The most interesting feature of this theory is that it accounts for a parabolic variation of the transverse shear strains across the thickness and satisfies the zero traction boundary conditions on the top and bottom surfaces of the plate without using shear correction factors. Buckling of orthotropic laminates subjected to biaxial inplane is investigated. Using the Navier solution method, the differential equations have been solved analytically and the critical buckling loads presented in closed-form solutions. The sensitivity of critical buckling loads to the effects of curvature terms and other factors has been examined. The analysis is validated by comparing results with those in the literature.

• Wind and Structures
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• 제25권5호
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• pp.415-432
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• 2017

The nonlinear aerodynamic instability of a tensioned plane orthotropic membrane structure is theoretically investigated in this paper. The interaction governing equation of wind-structure coupling is established by the Von $K\acute{a}rm\acute{a}n's$ large amplitude theory and the D'Alembert's principle. The aerodynamic force is determined by the potential flow theory of fluid mechanics and the thin airfoil theory of aerodynamics. Then the interaction governing equation is transformed into a second order nonlinear differential equation with constant coefficients by the Bubnov-Galerkin method. The critical wind velocity is obtained by judging the stability of the second order nonlinear differential equation. From the analysis of examples, we can conclude that it's of great significance to consider the orthotropy and geometrical nonlinearity to prevent the aerodynamic instability of plane membrane structures; we should comprehensively consider the effects of various factors on the design of plane membrane structures; and the formula of critical wind velocity obtained in this paper provides a more accurate theoretical solution for the aerodynamic stability of the plane membrane structures than the previous studies.

• 소음진동
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• 제10권2호
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• pp.291-298
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• 2000

This paper intends to provide an analytic vibrational model of non-circular cutting by a lathe and to investigate its stability criteria. A single degree-of-freedon model based on the orthogonal cutting theory has the characteristics of parametric excitation due to the nonlinear cutting force that changes periodically its direction as well as its magnitude. The Floquet theory has been applied to investigate the stability of the linearized system and the stability diagrams have been obtained with respect to the ovality, the cut velocity and the cut depth. Also nonlinear analysis has been performed to verify the linear analysis and compare the results with those from circular cutting. Results show that a critical cut depth is decreased as the ovality is increased while a critical cut velocity is increased as the ovality is increased. Also, a good agreement in critical conditions has been observed between the linear and nonlinear analyses for the ovality less than 2%. Accordingly, the linear analysis can be said to be applicable for most practical oval cuttings whose ovality are much less than 2%.

• 한국의류학회지
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• 제44권2호
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• pp.273-294
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• 2020

Considering the complex relationship between fashion curating and the critical approach of fashion exhibition reviews, this study explores the current state of fashion criticism in museology, focusing on fashion designer exhibition reviews of Fashion Theory. The author selected eighteen exhibition reviews of individual fashion designers' works from 1997 on to the current 2020 issues of Fashion Theory, which provides an interdisciplinary forum to analyze fashion as a cultural construction. The author performed a systematic review that qualitatively summarizes and/or synthesizes the findings of the studies on the topic with the process of a systematic review, such as key question formulation, analytic framework building, evidence mapping, critical appraisal, and evidence synthesis. The results of this study are as follows. First, the exhibition reviews included almost all stages of the inclusive fashion criticism model, based on an artifact study. Second, they reflected various critical discourses that offered current interpretations of historical and contemporary fashion. Third, they showed that fashion criticism in the museum context is the result of an interdisciplinary collaboration of various fashion agents. Finally, they offered a bridge for crossing the boundaries of various scholarly fields, as they combine multidisciplinary scholarship with object-based methods.

• Korean Chemical Engineering Research
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• 제50권1호
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• pp.61-65
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• 2012

이성분 용융액의 시간의존형 응고계에서 mush 층의 대류발생을 선형 안정성 이론으로 해석하였다. 본 연구에서는 근공융물 mush 층을 다공성 블록으로 가정한 단순화된 모델에 전파이론을 적용하여 대류발생 임계조건을 구하였다. 본 연구 모델에서는 기존의 실험결과 및 mush층 위의 액체층을 포함하여 고려한 이론적 연구의 결과보다 더 높은 임계 Rayleigh 수가 얻어졌다. mush 층의 윗 경계면에 일정압력(투과)조건을 적용하는 경우가 비투과조건에 비해 임계 Rayleigh 수를 더 작게 하며 염화암모늄 수용액의 응고실험결과와 더 근접한 것으로 조사되었다.