• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집C
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• pp.537-542
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• 2001

In recent engineering, the designer has become more and more dependent on computer simulation. But defining exact model using computer simulation is too expensive and time consuming in the complicate systems. Thus, designers often use approximation models, which express the relation between design variables and response variables. These models are called metamodel. In this paper, we introduce one of the metamodel, named Kriging. This model employs an interpolation scheme and is developed in the fields of spatial statistics and geostatistics. This class of interpolating model has flexibility to model response data with multiple local extreme. By reason of this multi modality, we can't use any gradient-based optimization algorithm to find global extreme value of this model. Thus we have to introduce global optimization algorithm. To do this, we introduce DE(Differential Evolution). DE algorithm is developed by Ken Price and Rainer Storn, and it has recently proven to be an efficient method for optimizing real-valued multi-modal objective functions. This algorithm is similar to GA(Genetic Algorithm) in populating points, crossing over, and mutating. But it introduces vector concept in populating process. So it is very simple and easy to use. Finally, we show how we determine Kriging metamodel and find global extreme value through two mathematical examples.

• 대한전자공학회논문지SP
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• 제42권3호
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• pp.1-6
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• 2005

변이 영상을 마코브 랜덤필드(MRF)로 모델링한 마코브 네트워크에서 신뢰확산 알고리듬은 각 화소에 대응되는 노드들 사이에 메시지를 전달하는 방식으로 이루어진다. 최초 메시지는 알고리듬의 반복을 통해 특정한 값으로 수렴하게 되며, 수렴된 값을 얻기 위해서는 많은 알고리듬의 반복이 필요하다. 본 논문에서는 알고리듬의 반복을 줄이기 위해 영상내 물체들을 선들의 조합 구성으로 보고 각각의 선들은 같은 메시지를 갖는 노드들의 집합으로 간주하여 기존의 신뢰확산 알고리듬을 단순화하였다.

• 대한수학회지
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• 제57권3호
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• pp.721-745
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• 2020

In this paper we study fractional Sobolev spaces characterized by a norm based on eigenfunction expansions. The goal of this paper is twofold. The first one is to define fractional Sobolev spaces of order -1 ≤ s ≤ 2 equipped with a norm defined in terms of Neumann eigenfunction expansions. Due to the zero Neumann trace of Neumann eigenfunctions on a boundary, fractional Sobolev spaces of order 3/2 ≤ s ≤ 2 characterized by the norm are the spaces of functions with zero Neumann trace on a boundary. The spaces equipped with the norm are useful for studying cross-sectional traces of solutions to the Helmholtz equation in waveguides with a homogeneous Neumann boundary condition. The second one is to define fractional Sobolev spaces of order -1 ≤ s ≤ 1 for vector-valued functions in a simply-connected, bounded and smooth domain in ℝ². These spaces are defined by a norm based on series expansions in terms of eigenfunctions of the vector Laplacian with boundary conditions of zero tangential component or zero normal component. The spaces defined by the norm are important for analyzing cross-sectional traces of time-harmonic electromagnetic fields in perfectly conducting waveguides.

• 한국정보통신학회논문지
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• 제17권3호
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• pp.627-633
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• 2013

무선이동통신 시스템에서 두 수열의 상호상관 함숫값은 통화 품질과 사용자 수를 결정하는데 있어 큰 영향을 끼치고 있다. 본 논문에서는 주기 $2^n-1$인 m-수열에 새로운 데시메이션 $d=\frac{2^{m-st-1}}{2^s-1}(2^n+2^{st+s+1}-2^{m+st+1}-1)$를 적용하여 또 다른 m-수열을 생성하고 두 수열의 상호상관 함숫값과 그 값들의 발생횟수를 결정한다.

• 한국의류학회지
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• 제33권1호
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• pp.127-138
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• 2009

This study is about the analysis on symbolic meaning and kunstwollen of Issey Miyake's art works which is influenced by various external factors such as social and cultural background, nationality and philosophy. Especially, this research focused on 'Pleats Please Issey Miyake' and 'A Piece of Cloth' which are the core of his works. The most important concept of Issey Miyake's works is the relationship of human body and a piece of cloth. Miyake's clothes has provided the time and the space where inspires the vitality into wearer. He accomplishes the most perfect beauty through incomplete beauty of cloth. Miyake wants to express the emotion of the human being through his clothes and tries to make special code between creator, wearer and viewer. Fashion is accomplished in connection with human body, not exists just as 'clothes'. Fashion has valued as an art which expresses the ideology and the sentiment of human being most directly. Issey Miyake who has tried to express human life and emotion has promoted fashion as an important part of art. Miyake is accepting and delivering the history and culture, expressing and communicating empathy, and combining the different fields harmoniously.

• ETRI Journal
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• 제41권1호
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• pp.93-108
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• 2019

Guaranteeing interoperability between devices and applications is the core role of standards organizations. Since its first JPEG standard in 1992, the Joint Photographic Experts Group (JPEG) has published several image coding standards that have been successful in a plethora of imaging markets. Recently, these markets have become subject to potentially disruptive innovations owing to the rise of new imaging modalities such as light fields, point clouds, and holography. These so-called plenoptic modalities hold the promise of facilitating a more efficient and complete representation of 3D scenes when compared to classic 2D modalities. However, due to the heterogeneity of plenoptic products that will hit the market, serious interoperability concerns have arisen. In this paper, we particularly focus on the holographic modality and outline how the JPEG committee has addressed these tremendous challenges. We discuss the main use cases and provide a preliminary list of requirements. In addition, based on the discussion of real-valued and complex data representations, we elaborate on potential coding technologies that range from approaches utilizing classical 2D coding technologies to holographic content-aware coding solutions. Finally, we address the problem of visual quality assessment of holographic data covering both visual quality metrics and subjective assessment methodologies.

• Advances in nano research
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• 제14권1호
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• pp.103-115
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• 2023

Recent developments in the synthesis of nanomagnesia of controlled sizes and shapes that are suitable for various applications are reviewed. Two main methods, based on liquid-phase synthesis, i.e., chemical methods and bio-based methods, are used to synthesize nanomagnesia. Conventionally, nanomagnesia was synthesized by chemical methods such as coprecipitation, sol-gel, combustion method, and so on using different chemical agents and stabilizers which later on become responsible for several biological risks because of the toxicity of used chemicals. Bio-based protocols are growing as another environmental friend method for the synthesis of various nanostructures especially nanomagnesia using biomass, plant extracts, alga, and fungi as a source of precursor material. The ideal method should offer better control of textural properties of nanostructures and decrease the necessity for purification of the synthesized nanoproducts, which sequentially removes the use of large amounts of chemicals and organic solvents and manipulation of products that are unsafe to the environment. Finally, the broad applicability of nanomagnesia in diverse areas is presented. Employment of nanomagnesia reported in several laboratory and industrial fields are valued from the standpoint of the significance of these issues for technological requests, as described in the literature. Nanomagnesia has various applications such as antimicrobial performance, removing pollutants, batteries application, and catalysis.

• Nonlinear Functional Analysis and Applications
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• 제28권2호
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• pp.497-520
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• 2023

Numerous problems in science and engineering defined by nonlinear functional equations can be solved by reducing them to an equivalent fixed point problem. Fixed point theory provides essential tools for solving problems arising in various branches of mathematical analysis, such as split feasibility problems, variational inequality problems, nonlinear optimization problems, equilibrium problems, complementarity problems, selection and matching problems, and problems of proving the existence of solution of integral and differential equations.The theory of fixed is known to find its applications in many fields of science and technology. For instance, the whole world has been profoundly impacted by the novel Coronavirus since 2019 and it is imperative to depict the spread of the coronavirus. Panda et al. [24] applied fractional derivatives to improve the 2019-nCoV/SARS-CoV-2 models, and by means of fixed point theory, existence and uniqueness of solutions of the models were proved. For more information on applications of fixed point theory to real life problems, authors should (see [6, 13, 24] and the references contained in).

• 한국정보통신학회논문지
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• 제13권9호
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• pp.1837-1844
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• 2009

본 논문에서는 전류모드 CMOS에 의한 2변수 3치 가산기 회로와 승산기 회로를 구현하였다. 제시된 전류모드 CMOS에 의한 3치 가산기 회로와 승산기 회로는 전압 레벨로 동작하며, HSpice 시뮬레이션을 통하여 이 회로들에 대하여 동작 특성을 보였다. 제시 된 회로들은 $0.180{\mu}m$ CMOS 표준 기술을 사용하여 HSpice로 시뮬레이션 하였다. 2 변수 3치 가산기 및 승산기 회로의 단위 전류 $I_u$는 $5{\mu}A$로 하였으며, NMOS의 길이와 폭 W/L는 $0.54{\mu}m/0.18{\mu}m$이고, PMOS의 길이와 폭 W/L는 $1.08{\mu}m/0.18{\mu}m$이다. VDD 전압은 2.5V를 사용하였으며 MOS 모델은 LEVEL 47으로 시뮬레이션 하였다. 전류모드 CMOS 3치 가산기 및 승산기 회로의 시뮬레이션 결과에서 전달 지연 시간이 $1.2{\mu}s$이며, 3치 가산기 및 승산기 회로가 안정하게 동작하여 출력 신호를 얻는 동작 속도가 300MHz, 소비 전력이 1.08mW임을 보였다.

• 한국컴퓨터정보학회논문지
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• 제17권1호
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• pp.19-30
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• 2012

다양한 정보기기와 소셜네트워크시스템, 그리고, 클라우드컴퓨팅환경 등과 같은 인터넷기반의 인프라를 토대로 분산화되고 공유가능한 데이터가 폭발적으로 증가하고 있다. 최근에는 데이터에 내재되어 있는 유용한 정보와 지식을 추출하고 분석 및 분류하기 위한 데이터분석 및 마이닝기법으로서, 이진데이터 또는 다치데이터에 관한 형식개념분석기법에 관한 연구가 활발하게 진행되어 다양한 분야에서 성공적으로 활용되고 있다. 그러나, 각 속성들이 구간값을 갖는 형태로 이루어진 구간데이터의 분석에 대한 형식개념분석에 관한 연구는 많이 수행되지 못하였다. 본 논문에서는, 구간데이터를 분석하기 위하여 형식개념분석기법을 기반으로 하는 새로운 분류기법을 제안한다. 또한, 구간데이터의 이진화, 개념추출 및 개념계층구조 구축 등, 본 논문에서 제안한 새로운 분류기법을 지원하기 위한 도구(iFCA)의 구축에 관하여 소개하고, 마지막으로, 몇가지 실세계의 데이터를 대상으로 한 실험결과를 토대로, 본 논문에서 제안하는 분류기법의 유용성에 대해서 설명한다.