• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 추계학술대회 논문집
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• pp.321-321
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• 2009

This paper presents quasi-zero-stiffness (QZS) characteristic of a passive isolator using flexures under compression force. The passive isolator consists of a positive stiffness element (a vertical coil spring) and a negative stiffness element (flexures under compression force), and their proper combination of the positive and negative stiffness elements can produce both substantial static and zero dynamic stiffness, so called QZS. Firstly, a nonlinear dimensionless expression of a flexure under compression force is derived. A dynamic model of the passive isolator is developed and numerical simulations of its time and frequency response are performed. Then, undesirable nonlinear vibration is quantified using a period doubling bifurcation diagram and a Poincare's map of the isolator under forced excitation. Finally, experiments are performed to validate the QZS characteristic of the passive isolator.

• ETRI Journal
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• 제30권3호
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• pp.355-364
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• 2008

Multiple-input multiple-output (MIMO) systems can provide significant increments in capacity; however, the capacity of MIMO systems degrades severely when spatial correlation among multipath channels is present. This paper demonstrates that the influence of shadowing on the channel capacity is more substantial than that of multipath fading; therefore, the shadowing effect is actually the dominant impairment. To overcome the composite fading effects, we propose combining macroscopic selection diversity (MSD) schemes with MIMO technology. To analyze the system performance, the capacity outage expression of MIMO-based MSD (MSD-MIMO) systems using a characteristic function is applied. The analytic results show that there are significant improvements when MSD schemes are applied, even for the two-base-station diversity case. It is also observed that the effect of spatial correlation due to multipath fading is almost negligible when multiple base stations cooperatively participate in the mobile communication topology.

• 한국실내디자인학회논문집
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• 제14권2호
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• pp.46-54
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• 2005

This study is about the polyphony music proportion which appears today in the Architecture space. In the field of interior architecture, there have been many tries of applying characteristics of music, such as abstraction and nature of time for users of space to have new experience. It has been possible because architecture and music have similarities in many ways. Regarding using proportional characteristic in architecture and music, the both fields are enormously related in some ways. The purpose of this study is explaining of possibility of architectural expression in music and suggesting a way of analysing architectural design based on musical elements emphasizing proportional characteristic. Therefore, it is going to analyse Counterpoint of Bach, which is well expressed in music and compare it with proportional characteristic of space through this study.

• 전기학회논문지
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• 제58권8호
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• pp.1624-1632
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• 2009

In this study, we introduce the design methodology of an optimized Interval Type-2 fuzzy controller. The fixed MF design of type-1 based FLC leads to the difficulty of rule-based control design for representing the linguistically uncertain expression. In the Type-2 FLC as the expanded type of Type-1 FLC, we can effectively improve the control characteristic by using the footprint of uncertainty(FOU) of membership function. Type-2 FLC has a robust characteristic in the unknown system with unspecific noise when compared with Type-1 FLC. Through computer simulation as well as practical experiment, we compare their performance by applying both the optimized Type-1 and Type-2 fuzzy cascade controllers to ball and beam system. To evaluate each controller performance, we consider controller characteristic parameters such as maximum overshoot, delay time, rise time, settling time and steady-state error.

• 한국실내디자인학회논문집
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• 제14권6호
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• pp.37-46
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• 2005

This study is focused on the indeterminacy of the contemporary social structure based on the philosophical concept of relationship. The purpose of this study is to present the index of the space planning that the contemporary society demands through analysis of a characteristics of the indeterminate program. As the result, we got a characteristic and a design method of the following indeterminate programs. (1)The characteristic of the interior space programs are in such cases as combined, the continuance, the pile, the juxtaposition, mixing and interference etc. (2) The characteristics of space planning are multiple changes of the space occupation, various sight experiences, folding structure, expansion of flow space, the insertion of a between spates etc. (3) The characteristic of space design expression is addition of various functions tv unification of a structural element and an element of furniture.

• 대한수학회보
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• 제46권5호
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• pp.941-947
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• 2009

Let q be a power of 16. Every polynomial $P\in\mathbb{F}_q$[t] is a strict sum $P=A^2+A+B^3+C^3+D^3+E^3$. The values of A,B,C,D,E are effectively obtained from the coefficients of P. The proof uses the new result that every polynomial $Q\in\mathbb{F}_q$[t], satisfying the necessary condition that the constant term Q(0) has zero trace, has a strict and effective representation as: $Q=F^2+F+tG^2$. This improves for such q's and such Q's a result of Gallardo, Rahavandrainy, and Vaserstein that requires three polynomials F,G,H for the strict representation $Q=F^2$+F+GH. Observe that the latter representation may be considered as an analogue in characteristic 2 of the strict representation of a polynomial Q by three squares in odd characteristic.

• 천문학회보
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• 제37권2호
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• pp.160.1-160.1
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• 2012

We present an alternative approach for satellite formation reconfiguration by an optimal impulsive-thrust strategy to minimize the total characteristic velocity in a near-circular-orbit. Linear transformation decouples the Hill-Clohessy-Wiltshire(HCW) dynamics into a new block-diagonal system matrix consisting of 1-dimensional harmonic oscillator and 2-dimensional subsystem. In contrast to a solution based on the conventional primer vector theory, the optimal solution and the necessary conditions are represented as times and directions of impulses. New analytical expression of the total characteristic velocity is found for each sub systems under general boundary conditions including transfer time constraint. To minimize the total characteristic velocity, necessary conditions for times and directions of impulses are analytically solved. While the solution to the 1-dimensional harmonic oscillator has been found, the solution to the 2-dimensional subsystem is currently under construction. Our approach is expected to be applicable to more challenging problems.

• Structural Engineering and Mechanics
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• 제10권2호
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• pp.111-123
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• 2000

An asymptotic solution for snap-through buckling of single-layer squarely-reticulated shallow spherical shells continuously supported on springs is developed in this paper. Based on the fundamental governing equations and boundary conditions, a nondimensional analytical expression associated with the external load, stiffness of spring and central transverse displacement (deflection) is derived with the aid of asymptotic iteration method. The effects of stiffness of spring and characteristic geometrical parameter on buckling of the structures are given by the analyses of numerical examples. In a special case, for reticulated circular plates, the influence of stiffness of spring on the characteristic relation between load and deflection is also demonstrated.

• 한국콘텐츠학회논문지
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• 제21권3호
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• pp.131-142
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• 2021

본 연구는 그림책 속 그림 디자인에 기초한 것으로, 그림책 속 일러스트레이션의 공간 표현은 매우 중요한 객관성을 담고 있다. 그림속의 다양한 텍스트, 그림, 여백 등은 작업자의 다양한 편집기술과 합리적 요소를 가지고 있어야 공간배치가 원활히 이루어진다. 본 논문은 여러 그림 사례와 고전적인 그림책에 대한 연구를 분석하여 그림책 속 디자인의 공간 표현의 특징을 도출하였다. 첫째 그림과 텍스트의 융합, 즉 그림과 텍스트 모두 화면의 요소로서 함께 공간 정보를 전달한다는 점이다. 둘째 그림책 속 공간 디자인의 일관성 특징으로, 책을 열람할 때 이야기와 내용을 부드럽게 연결시켜야 한다. 셋째 공간 표현 시 창작자가 필요에 따라 추상적 공간 표현과 구상적 공간 표현 중에서 서로 장단점을 활용하여야 한다는 점이다. 넷째는 그림책 공간 표현의 상징적 특징으로, 기호학 원리에 따라 그림책의 공간 표현에 많은 상징적 표현 수법이 적용됨을 알 수 있으며 이는 그림책 열람의 인지적 효율을 크게 향상시킨다. 다섯째 특징은 우수한 그림책의 공간 표현은 재미있는 요소가 뛰어나며 디자인 수단이 풍부하고 화면 내용과 화면 형식을 독자들에게 재미나게 전달한다는 점이다. 본 연구는 그림책 디자인에 있어서 디자이너와 아티스트가 이 같은 주어진 공간프레임 안에서 창작을 이끌어내야 하며 이러한 공간프레임은 그림책창작의 효율성을 크게 향상시킬 수 있을 뿐 아니라, 시각적으로 독자중심적인 흥미로운 체험을 제공할 수 있을 것이라고 생각된다.

• 한국실내디자인학회:학술대회논문집
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• 한국실내디자인학회 2007년도 춘계학술대회 논문집
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• pp.260-263
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• 2007

A church architecture which has an important meaning as a place which is for worship God, relationship, education, evangelism, service and formative meaning that express as a specific form. It has been changed by age or changes of theology, also its structure and form has been changed so as to change of a rutual. the church architecture that has been authorized as a architecture which is a representation of the age does not represent the age and it has weaknesses for expression of unique identification church has. Also, because it is lacking thoughts about regional viewpoint, it loses the characteristic of regional "landmark" like the past. In addition, a place of worship has been changed materiality of space like auditorium or seats so as to change of consciousness of worship, and it is exposed problems of expression of identification. Therefore the church architecture of twenty first centry needs to holy and be able to deliver their new standards and needs that fit original purpose of church for users.