• Honam Mathematical Journal
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• v.29 no.2
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• pp.269-277
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• 2007

Let L := L(G) denote the classical modular Lie algebra of $E_6$-type over an algebraically closed field F of characteristic p > 5 associated with some simple and simply connected algebraic group G. After the prototypes of those for $E_8$-type in [4], we shall search for irreducible (=simple) L-modules in this paper.

• Journal of the Korean Mathematical Society
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• v.54 no.6
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• pp.1853-1878
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• 2017

Let $\{U(t,s)\}_{t{\geq}s}$ be a periodic evolutionary process with period ${\tau}$ > 0 on a Banach space X. Also, let L be the generator of the evolution semigroup associated with $\{U(t,s)\}_{t{\geq}s}$ on the phase space $P_{\tau}(X)$ of all ${\tau}$-periodic continuous X-valued functions. Some kind of variation-of-constants formula for the solution u of the equation $({\alpha}I-L)^nu=f$ will be given together with the conditions on $f{\in}P_{\tau}(X)$ for the existence of coefficients in the formula involving the monodromy operator $U(0,-{\tau})$. Also, examples of ODEs and PDEs are presented as its application.

• Journal of applied mathematics & informatics
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• v.19 no.1_2
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• pp.179-190
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• 2005

We deal with the Cauchy problem for the space-time fractional diffusion equation, which is obtained from standard diffusion equation by replacing the second-order space derivative with a Caputo (or Riemann-Liouville) derivative of order ${\beta}{\in}$ (0, 2] and the first-order time derivative with Caputo derivative of order ${\beta}{\in}$ (0, 1]. The fundamental solution (Green function) for the Cauchy problem is investigated with respect to its scaling and similarity properties, starting from its Fourier-Laplace representation. We derive explicit expression of the Green function. The Green function also can be interpreted as a spatial probability density function evolving in time. We further explain the similarity property by discussing the scale-invariance of the space-time fractional diffusion equation.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• fall
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• pp.126-128
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• 2021

MPEG(Moving Picture Experts Group) 비디오 그룹은 사용자에게 움직임 시차(motion parallax)를 제공하면서 3D 공간 내에서 임의의 위치와 방향의 시점(view)을 렌더링(rendering) 가능하게 하는 6DoF(Degree of Freedom)의 몰입형 비디오 부호화 표준인 MIV(MPEG Immersive Video) 표준화를 진행하고 있다. MIV 표준화 과정에서 참조 SW 인 TMIV(Test Model for Immersive Video)도 함께 개발하고 있으며 점진적으로 부호화 성능을 개선하고 있다. TMIV 는 여러 뷰로 구성된 방대한 크기의 6DoF 비디오를 압축하기 위하여 입력되는 뷰 비디오들 간의 중복성을 제거하고 남은 영역들은 각각 개별적인 패치(patch)로 만든 후 아틀라스에 패킹(packing)하여 부호화되는 화소수를 줄인다. 이때 아틀라스 비디오에 패킹된 패치들의 위치 정보를 메타데이터로 압축 비트열과 함께 전송하게 되며, 본 논문에서는 이러한 패킹 정보를 보다 효율적으로 표현하기 위한 방법을 제안한다. 제안방법은 기존 TMIV10.0 에 비해 약 10%의 메타데이터를 감소시키고 종단간 BD-rate 성능을 0.1% 향상시킨다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2020.07a
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• pp.119-122
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• 2020

소스 코드가 없는 악성코드를 분석하거나 소프트웨어 취약점 분석을 위해 바이너리 분석이 요구된다. 바이너리 분석을 위한 도구 중 어셈블러는 사용자의 입력 없이 컴파일러 내부에서 수행되기 때문에 사용자 관점의 연구는 많지 않다. 그러나 바이너리 분석 과정 중 역어셈블과 중간언어(Intermediate Representation)의 정확성을 검증하기 위해 사용자가 어셈블리어를 입력하여 결과를 확인할 수 있는 어셈블러가 요구된다. 본 논문에서는 어셈블리어를 바이너리 코드로 변환하는 어셈블러 도구를 함수형 언어인 F#으로 구현하여 어셈블리 과정을 효율적으로 설계한 어셈블러 도구를 제안한다. F#의 강력한 패턴 매칭 기능을 사용하여 수백개의 명령어를 일괄적이고 직관적으로 처리하는 과정을 설계하고 구현하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.11a
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• pp.639-642
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• 2005

융합과 필터링(Fusion and Filtering: F/F) 기법은 신호처리, 제어 등 많은 공학분야에서 사용되며 현재 파티클 필터(Particle Filter: PF)가 최근 가장 각광받고 있다. 그러나 비선형 시스템과 모델링 하기 어려운 에러조건 때문에 기존의 파티클 필터조차 제대로 다루지 못하는 공학환경이 존재한다. 이에 파티클 필터뿐만 아니라 칼만 계열(Kalman varieties)의 필터 방법들을 통합할 수 있는 Constraint Manifold(CM) 기반 융합과 필터링 방법이 제안되었다. 본 논문에서는 CM 기반 필터링을 효과적으로 수행할 수 있도록 제한 조건 표현에 대한 방법론을 제시하면 시뮬레이션을 통해 기존 파티클 필터와의 성능 비교를 수행하였다.

• ETRI Journal
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• v.33 no.6
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• pp.945-948
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• 2011

Object-based audio coding can provide new music applications with interactivity. To efficiently compress a lot of target audio objects, a subband-based parametric coding scheme has been adopted for MPEG spatial audio object coding. In this letter, the time-frequency (T/F) subband analysis structure is investigated. A reconfigured T/F structure is also proposed to enhance the generating performance of sound scenes such as 'karaoke' and 'solo' play in interactive music scenarios. From the experimental results, it was confirmed that the proposed scheme remarkably improves the SNR and sound quality.

• The Journal of Society for e-Business Studies
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• v.26 no.3
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• pp.119-132
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• 2021

Identification of associated knowledge based on content relevance is a fundamental functionality in managing service and security of core knowledge. This study compares the performance of methods to identify associated knowledge based on content relevance, i.e., the associated document network composition performance of keyword-based and word-embedding approach, to examine which method exhibits superior performance in terms of quantitative and qualitative perspectives. As a result, the keyword-based approach showed superior performance in core document identification and semantic information representation, while the word embedding approach showed superior performance in F1-Score and Accuracy, association intensity representation, and large-volume document processing. This study can be utilized for more realistic associated knowledge service management, reflecting the needs of companies and users.

• Science of Emotion and Sensibility
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• v.20 no.4
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• pp.101-112
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• 2017

We investigated the neural representation of reward probability recognition and its neural connectivity with other regions of the brain. Using functional magnetic resonance imaging (fMRI), we used a simple guessing task with different probabilities of obtaining rewards across trials to assay local and global regions processing reward probability. The results of whole brain analysis demonstrated that lateral prefrontal cortex, inferior parietal lobe, and postcentral gyrus were activated during probability-based decision making. Specifically, the higher the expected value was, the more these regions were activated. Fronto-parietal connectivity, comprising inferior parietal regions and right lateral prefrontal cortex, conjointly engaged during high reward probability recognition compared to low reward condition, regardless of whether the reward information was extrinsically presented. Finally, the result of a regression analysis identified that cortico-subcortical connectivity was strengthened during the high reward anticipation for the subjects with higher cognitive impulsivity. Our findings demonstrate that interregional functional involvement is involved in valuation based on reward probability and that personality trait such as cognitive impulsivity plays a role in modulating the connectivity among different brain regions.

• Journal of Science Education
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• v.43 no.1
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• pp.173-193
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• 2019

An expert teachers' instruction can be helpful to other teachers because good teaching effectively guides students to develop meaningful learning. Feynman is an excellent physics lecturer as well as one of the greatest physicists of the 20th century who presented and explained physics with his unique teaching style based on his great store of knowledge. However, it is not easy to capture and visualize teaching because it is not only the complex phenomena interrelated to various factors with the content to be taught but also the tacit representation. In this study, the framework of knowledge & belief based on the integrated mental model theory was used as a tool to capture and visualize complex and tacit representation of Feynman's teaching of 'The theory of gravitation,' a chapter in The Feynman Lectures on Physics. Feynman's teaching was found to go beyond the transmission of physics concepts by showing that components of the framework of knowledge & belief were effectively intertwined and integrated in his teaching and the storyline was well-organized. On the basis of these discussions, the implications of Feynman's teaching analyzed within the framework of knowledge & belief for physics teacher education are derived. Finally, the characteristics of the framework of knowledge & belief as tools for the analysis of teaching are presented.