• 한국문헌정보학회지
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• 제29권
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• pp.173-204
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• 1995

The purpose of this study is to promote understanding of the book selection theory by researching dialectically of its development process centering on the BSTv(value theory) and BSTd(demand theory). The results of this study are summarized as follows 1. In the period of enlightenment and education, the book selection theory of public libraries was the thesis state of BSTv(d). 2. Antithesis state of BSTv(d), that is, BSTd was raised to real central theory of book selection in the early 20th century. 3. In the 1930-40's, BSTv and BSTd were transformed into balance state or coexistence relations(BSTb $[v(d){\cdot}d(v)$]. 4. After World War II, BSTn(library needs theory) and BSTo(library objective theory) were evoked, and opposed to the existing selection theories. Now, they are developing into BSTbl$[n(d)\cdot\;o(v)\;or\;n(d){\cdot}v(o)]$.

• 항공우주시스템공학회지
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• 제11권5호
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• pp.13-19
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• 2017

본 연구에서는 굽힘 하중을 받는 복합재료 적층판의 파손 해석을 위하여 2D 변형률 기반 파손 이론을 적용하였다. 복합재료 적층판의 비선형 기계적 거동을 모사하기 위하여, 선형 증분 접근 방식을 적용하고 단위 길이 적층판에 대한 점진적 파손 해석을 수행하였다. 크로스플라이 및 준등방성 적층 패턴에 대하여 3점 굽힘 시험을 수행하고 해석 결과와 비교 검증하였다.

• Structural Engineering and Mechanics
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• 제86권6호
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• pp.731-738
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• 2023

This article presents an analytical approach to explore the bending behaviour of of two-dimensional (2D) functionally graded (FG) nanobeams based on a two-variable higher-order shear deformation theory and nonlocal strain gradient theory. The kinematic relations are proposed according to novel trigonometric functions. The material gradation and material properties are varied along the longitudinal and the transversal directions. The equilibrium equations are obtained by using the virtual work principle and solved by applying Navier's technique. A comparative evaluation of results against predictions from literature demonstrates the accuracy of the proposed analytical model. Moreover, a detailed parametric analysis checks for the sensitivity of the bending and stresses response of (2D) FG nanobeams to nonlocal length scale, strain gradient microstructure scale, material distribution and geometry.

• 대한화학회지
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• 제21권5호
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• pp.339-352
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• 1977

소성변형에 대한 저자들의 이론(제1보)을 요업재료, 금속, 합금 및 단결정들에 적용하였다. 그 결과 다중 결정에서는 dislocation 운동과 grain boundary 운동이 실험조건에 따라 함께 또는 분리되어 나타나는 반면 단결정에서는 dislocation 운동만 나타났다. 유동식에 나타나는 파라미터$({\alpha}_{d1},\;1/{\beta}_{d1})와\;({\alpha}_{gj}/X_{gj},\;1/{\beta}_{gj})$ (j = 1 or 2) 및 활성화엔탈피 ${\Delta}H_{k1}^{\neq}$ (k = d 혹은 g)를 구하여 예측한 소성변형은 실험과 잘 일치함을 보았다. 여기서 첨자 d1는 첫번째의 dislocation 유동단위, gj는 j번째 grain boundary 유동단위를 나타낸다. 활성화엔탈피에 대하여 ${\Delta}H_{d1}^{\neq}$는 bulk의 자체확산에 대한 활성화엔탈피와 일치하고 ${\Delta}H_{g1}^{\neq}$는 grain boundary 자체확산에 대한 활성화엔탈피와 일치하였다. 이 사실은 저자들의 이론의 정당성을 보이고 있다.

• Journal of Multimedia Information System
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• 제3권4호
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• pp.135-140
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• 2016

To improve the throughput of Device-to-Device (D2D) communication, we focus on the scenario where D2D pair can reuse multi-channel of cellular communication. However, as sharing same channel with cellular communication can cause interference between D2D communication and cellular communication, a proper interference management is needed. In this paper, we propose interference-based channel allocation to select the channels to be used by D2D communication and a solution from game theory perspective to optimize the D2D communication throughput under multi-channel as well as guarantee the interference from it to cellular network. The simulation results verify the stability of the proposed method.

• 복식
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• 제58권9호
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• pp.81-98
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• 2008

This research aims to analyze humorous images expressed in 2D graphics fashion illustrations and to propose application of 2D graphics in humorous images for fashion illustrations to suggest a more creative and relevant fashion illustration for contemporary culture. The result of this research were as follows: First, theories on reaction of humor can be classified into Incongruity theory, Superiority theory and Arousal and Relief theory. Humor in visual arts are classified in Visual Parody, Visual Pun, Visual Paradox and Visual Satire. Second, Visual Pun, Visual Parody, and Visual Satire are used for visualizing fashion illustration, and the foundations for many humor images were simple-colored, imaginative, and unreal settings. And it was also found out that the physical proportion of the models generally was 1(head):7(entire body), 1:8, 1:15 and the models were usually laughing and smiling. Tone was usually pastel and vivid, and posture was usually standing-position or sitting-position. Third, based on such results, fashion illustration works of humor image using 2D graphics were created. To concretize the humor image, 'gift' as a concept was chosen. Humor alleviates the tension and stress. It also brings laughter and pleasure to people's lives. Therefore humor image will be an effective way of expanding creativity in modern fashion illustration.

• 복합신소재구조학회 논문집
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• 제2권2호
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• pp.20-25
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• 2011

본 논문에서는 2차원 콘크리트 슬래브 철도교량을 특별직교이방성 복합적층판 이론으로 해석하였다. 슬래브의 해석에 있어 단면의 기하학적, 물리적 특성이 중립면에서 휨-연계강성 $B_{ij}$ = 0 이고, $D_{16}=D_{26}=0$임을 고려하였다. 교량상판은 특별직교이방성 판으로 거동한다. 이러한 경계조건을 갖는 단면 혹은 불규칙한 단면을 갖는 시스템은 해석적 해를 구하기가 매우 어렵다. 이러한 문제에 대한 해석을 위해서 유한차분법이 이용되었다. 본 논문에서는 보 이론과 유한차분법이 해석을 위해 사용되었다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권5호
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• pp.1984-2002
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• 2020

With the appearance of wireless spectrum crisis in traditional cellular network, device-to-device (D2D) communication has been regarded as a promising solution to ease heavy traffic burden by enabling precise content delivery among mobile users. However, due to the channel sharing, the interference between D2D and cellular users can affect the transmission rate and narrow the throughput in the network. In this paper, we firstly present a weighted interference minimization cluster formation model involving both social attribute and physical closeness. The weighted-interference, which is evaluated under the susceptible-infected(SI) model, is utilized to gather user in social and physical proximity. Then, we address the cluster formation problem via spectrum clustering with iterative operation. Finally, we propose the stable matching theory algorithm in order to maximize rate oriented to accomplish the one-to-one resource allocation. Numerical results show that our proposed scheme acquires quite well clustering effect and increases the accumulative transmission rate compared with the other two advanced schemes.

• Steel and Composite Structures
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• 제49권3호
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• pp.293-306
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• 2023

This article focuses on the study of the buckling behavior of two-dimensional functionally graded (2D-FG) nanosize tubes, including porosity, based on the first shear deformation and higher-order theory of the tube. The nano-scale tube is simulated using the nonlocal gradient strain theory, and the general equations and boundary conditions are derived using Hamilton's principle for the Zhang-Fu's tube model (as a higher-order theory) and Timoshenko beam theory. Finally, the derived equations are solved using a numerical method for both simply-supported and clamped boundary conditions. A parametric study is performed to investigate the effects of different parameters, such as axial and radial FG power indices, porosity parameter, and nonlocal gradient strain parameters, on the buckling behavior of the bi-dimensional functionally graded porous tube. Keywords: Nonlocal strain gradient theory; buckling; Zhang-Fu's tube model; Timoshenko theory; Two-dimensional functionally graded materials; Nanotubes; Higher-order theory.

• 한국콘텐츠학회논문지
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• 제7권7호
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• pp.87-95
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• 2007

본 연구에서는 미래의 영상 콘텐츠를 조작하는 사용자 인터페이스(User Interface)가 3차원 중심으로 변화할 것이라 예측하여, 지금까지의 2차원 인터페이스와 3차원 인터페이스간의 공통점과 차이점을 GUI(Graphic User Interface)의 원칙을 기준으로 연구하고 3차원 인터페이스의 특징을 가상현실의 원리를 통해 살펴보고자 하였다. 이러한 이론적 연구를 바탕으로 실재의 2차원 인터페이스를 3차원 인터페이스로 변경 제작하여 설문조사를 실시하였으며 개혁확산이론에 근거하여 작성된 설문조사의 분석을 통해 2D와 3D 인터페이스를 비교하고 3D 인터페이스가 차세대 영상 콘텐츠의 주력 인터페이스가 될 수 있는 지의 가능성의 여부를 타진해본 결과 기존의 인터페이스를 대신하여 더 많은 시장가치를 지닌 인터페이스로서의 면모를 발견할 수 있었다.