• Wind and Structures
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• 제12권5호
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• pp.457-474
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• 2009

Techniques for stabilising slender bridges under wind loads are presented in this article. A mathematically consistent description of the acting aerodynamic forces is essential when investigating these ideas. Against this background, motion-induced aerodynamic forces are characterised using a linear time-invariant transfer element in terms of rational functions. With the help of these functions, the aeroelastic system can be described in the form of a linear, time-invariant state-space model. It is shown that the divergence wind speed constitutes an upper bound for the application of the selected mechanical actuators. Even active control with full state feedback cannot overcome this limitation. The results are derived and explained with methods of control theory.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제27권3호
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• pp.160-179
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• 2023

In this paper, we investigate the existence and diameter of the approximate fixed point results on E-metric spaces (not necessarily complete) by using various cyclic contraction mappings, including the B-cyclic contraction, the Bianchini cyclic contraction, the Hardy-Rogers cyclic contraction, and so on. Additionally, we prove the approximate fixed point results for rational type cyclic contraction mappings, which were discussed mainly in [35] and [37], in the setting of E-metric space. Also, a few examples are provided to demonstrate our findings. Subsequently, we discuss some applications of approximate fixed point results in the field of applied mathematics rigorously.

• 한국경제지리학회지
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• 제17권1호
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• pp.147-159
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• 2014

본 연구는 2003년 11월부터 2013년 8월까지의 전국, 수도권, 비수도권, 강남, 강북지역 아파트 매매가격의 합리적 버블을 전체기간과 글로벌금융위기 전 후로 기간을 나누어 상태공간모형과 칼만필터를 이용해 추정하였다. 전체기간 중에 강남은 합리적 버블이 25.4%로 가장 높고 강북 21.3%, 수도권 20.1%, 전국 18.9%, 비수도권 14.3%로 나타났다. 글로벌 금융위기 이전에는 강남이 26.7% 강북 19.3%로 강남이 강북보다 약 7.4% 정도 버블이 높게 형성되어 있다. 이에 반해 글로벌 금융위기 이후에는 강남 13.2%, 강북 10.7%로 버블이 많이 붕괴되었으나 오히려 비수도권 지역은 이전기간 4.2%에서 이후기간 19.0%로 약 15% 상승을 하였다. 이는 강남, 강북을 포함한 수도권은 매매가격이 하락하고 임대료는 상승을 하였고 비수도권 지역은 공공기관 이전 등 각종 개발호재로 인해 매매가격이 상승한 것이 주요원인으로 생각된다.

• 한국전산유체공학회지
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• 제12권3호
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• pp.20-28
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• 2007

A fast and robust method of grid generation to multiple functions has been developed for flow analysis in three dimensional space. It is based on the Non-Uniform Rational B-Spline(NURBS) of an approximation method. Many of NURBS intrinsic properties are introduced and much more easily understood. The grid generation method, details of numerical implementation. examples of application, and potential extensions of the current method are illustrated in this paper. The object of this study is to develop the surface grid generation and the grid cluster techniques capable of resolving complex flows with shock waves, expansion waves, shear layers. The knot insert method of Non-Uniform Rational B-Spline seems well worked. In addition, NURBS has been widely utilized to generate grids in the computational fluid dynamics community. Computational examples associated with practical configurations have shown the utilization of the algorithm.

• Wind and Structures
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• 제10권3호
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• pp.215-232
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• 2007

This paper presents an aeroelastic analysis procedure to highlight the influence of wind velocity on the structural damping and frequency of a long span cable-stayed bridge. Frequency dependent self-excited forces in terms of flutter derivatives are expressed as continuous functions using rational function approximation technique. The aeroelastically modified structural equation of motion is expressed in terms of frequency independent modal state-space parameters. The modal logarithmic dampings and frequencies corresponding to a particular wind speed are then determined from the eigen solution of the state matrix.

• 대한수학회지
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• 제47권2호
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• pp.299-309
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• 2010

The Weyl group of a compact connected Lie group is a reflection group. If such Lie groups are locally isomorphic, the representations of the Weyl groups are rationally equivalent. They need not however be equivalent as integral representations. Turning to the invariant theory, the rational cohomology of a classifying space is a ring of invariants, which is a polynomial ring. In the modular case, we will ask if rings of invariants are polynomial algebras, and if each of them can be realized as the mod p cohomology of a space, particularly for dihedral groups.

• Kyungpook Mathematical Journal
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• 제60권1호
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• pp.117-125
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• 2020

In this paper, we first introduce new classes of Lipschitz algebras of infinitely differentiable functions which are extensions of the standard Lipschitz algebras of infinitely differentiable functions. Then we determine the maximal ideal space of these extended algebras. Finally, we show that if X and K are uniformly regular subsets in the complex plane, then R(X, K) is natural.

• 대한수학회보
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• 제57권1호
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• pp.207-218
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• 2020

Some modular representations of reflection groups related to Weyl groups are considered. The rational cohomology of the classifying space of a compact connected Lie group G with a maximal torus T is expressed as the ring of invariants, H*(BG; ℚ) ≅ H*(BT; ℚ)^W(G), which is a polynomial ring. If such Lie groups are locally isomorphic, the rational representations of their Weyl groups are equivalent. However, the integral representations need not be equivalent. Under the mod p reductions, we consider the structure of the rings, particularly for the Weyl group of symplectic groups Sp(n) and for the alternating groups A_n as the subgroup of W(SU(n)). We will ask if such rings of invariants are polynomial rings, and if each of them can be realized as the mod p cohomology of a space. For n = 3, 4, the rings under a conjugate of W(Sp(n)) are shown to be polynomial, and for n = 6, 8, they are non-polynomial. The structures of H*(BT^n-1; 𝔽_p)^A_n will be also discussed for n = 3, 4.

• 한국실내디자인학회논문집
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• 제1호
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• pp.72-75
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• 1992

Lighting made interior space visible and to recognize space itself. Sp9ace and form are established not themselves , but lighting. and dextrous treatment of natural light accomplished poeteic space. Inflowing of lighting in interior space is main factor to decide space character and image . That was recognized in interior space through many centries. At this point, this study was described for that present inflowing of lighting adapting space character and right method in lighting program. The present study is to present the planning method of the most appropriate and the most rational natural lighting in planing for lighting. Under this premise the followings are made ; I. An introduction , the purpose, the sphere, and the method of this study are stated. II, The present writer studied the general characteristics of natural lighting. III. this author studied the factor of decision on control and representation skill of lighting along the following. IV. Analyzing interior space in which the natural lighting is introduced through some literature and case studies. Physics, psychology, structure, equipment, material. V. The last, the author rearranged the results of this study.

• 한국주거학회논문집
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• 제17권1호
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• pp.85-95
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• 2006

Though the kitchens of traditional residence architecture are recognized as having significant importance to houses themselves, to women who are supposed to do most of the housekeeping work, they are generally thought to be irrational space. This study tries to show through a demonstrative way that the kitchen space of traditional houses is the sensible and rational living space for the health's sake of all family members in the relations among humans, space and environment. Through this study, we were able to see that the architectural work of our ancestors in designing space had different views from those of the West in that our ancestors had sought the outcome taking the interrelations among environment-humans-space seriously in order to shape the physical organization for human beings.