• Steel and Composite Structures
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• 제47권5호
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• pp.569-585
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• 2023

This paper proposes an efficient approach for the structural topology optimization of bi-directional functionally graded structures by incorporating popular radial basis functions (RBFs) into an implicit level set (ILS) method. Compared to traditional element density-based methods, a level set (LS) description of material boundaries produces a smoother boundary description of the design. The paper develops RBF implicit modeling with multiquadric (MQ) splines, thin-plate spline (TPS), exponential spline (ES), and Gaussians (GS) to define the ILS function with high accuracy and smoothness. The optimization problem is formulated by considering RBF-based nodal densities as design variables and minimizing the compliance objective function. A LS-RBF optimization method is proposed to transform a Hamilton-Jacobi partial differential equation (PDE) into a system of coupled non-linear ordinary differential equations (ODEs) over the entire design domain using a collocation formulation of the method of lines design variables. The paper presents detailed mathematical expressions for BiDFG beams topology optimization with two different material models: continuum functionally graded (CFG) and mechanical functionally graded (MFG). Several numerical examples are presented to verify the method's efficiency, reliability, and success in accuracy, convergence speed, and insensitivity to initial designs in the topology optimization of two-dimensional (2D) structures. Overall, the paper presents a novel and efficient approach to topology optimization that can handle bi-directional functionally graded structures with complex geometries.

• 미생물학회지
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• 제53권4호
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• pp.286-291
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• 2017

진핵 세포에서 히스톤의 변형은 크로마틴 구조를 조절하는 데에 있어서 중요한 메커니즘이다. Set1 복합체에 의한 히스톤 H3의 네 번째 라이신 잔기(H3K4)에 발생하는 메틸화는 다양하게 잘 알려져 있는 히스톤 변형 중 하나이다. Set1 complex는 H2B의 유비퀴틴화에 의존적으로 발생하는 H3K4 메틸화에 중요하다고 알려진 Swd2를 포함하여 7개의 소단위 단백질을 가지고 있다. Swd2는 Set1의 RNA recognition motif (RRM) 도메인 근처에 결합하여 Set1의 활성을 조절하고, 또 RNA의 3' 말단 형성에 관여하는 CPF (Cleavage and Polyadenylation Factors) 복합체의 구성성분이라고 보고되었다. 최근 보고들에 따르면, 이런 Swd2의 이중적인 기능이 서로 독립적으로 작용하며, Swd2 결실돌연변이 균주가 살지 못하는 이유가 CPF 복합체의 구성성분으로써의 기능 때문이라고 알려져 있다. 본 연구에서 우리는 Swd2가 Set1의 RRM 도메인에 결합하여 Set1의 활성을 조절할 수 있을 뿐만 아니라, Set1의 안정성에도 영향을 줄 수 있음을 발견하였다. 또 우리는 Swd2가 결합할 수 없는 truncated-Set1을 가지고 있는 ${\Delta}swd2$ 돌연변이가 사멸하지 않고 정상적으로 자라는 것을 관찰하였다. 이런 결과들은 Saccharomyces cerevisiae에서 H3K4 메틸화와 RNA 3' 말단 형성과정에서의 Swd2의 이중적인 기능이 서로 독립적인 것이 아님을 제안하다.

• East Asian mathematical journal
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• 제24권4호
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• pp.317-328
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• 2008

In this paper we introduce ${\pi}G{\alpha}$-LC sets, ${\pi}G{\alpha}-LC^*$ sets and ${\pi}G{\alpha}-LC^{**}$ sets and different notions of generalizations of continuous functions in topological space and discuss some of their properties. Further we prove pasting lemma for ${\pi}G{\alpha}-LC^{**}$ continuous functions and ${\pi}G{\alpha}-LC^{**}$ irresolute functions.

• 한국지능시스템학회논문지
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• 제20권3호
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• pp.356-361
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• 2010

M. Demirci[Vague groups, J. math. Anal. Appl. vol.230, pp. 142-156, 1999] studied the vague group operation on a crisp set as a fuzzy function and estabished the vague group structure on a crisp set. In this paper we consider bi-groups which are studied by A.A.A. Agboola and L.S. Akinola. And we also will define vague bi-groups and fuzzy bi-functions and we investigate some basic operations on the vague bi-group and fuzzy bi-functions.

• Kyungpook Mathematical Journal
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• 제60권3호
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• pp.423-443
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• 2020

Generalizations of essential arity of partial functions, based on essential sets of arguments, are introduced, and their interplay with the minor relation of functions is investigated.

• Kyungpook Mathematical Journal
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• 제46권1호
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• pp.119-130
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• 2006

A new class of functions is introduced in this paper. This class is called almost ${\delta}$-precontinuity. This type of functions is seen to be strictly weaker than almost precontinuity. By using ${\delta}$-preopen sets, many characterizations and properties of the said type of functions are investigated.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 가을 학술발표논문집(II)
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• pp.412-417
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• 1998

This paper provides accurate flexural vibration solutions for thick (Mindlin) sectorial plates. A Ritz method is employed which incorporates a complete set of admissible algebraic-trigonometric polynomials in conjunction with an admissible set of Mindlin “corner functions". These corner functions model the singular vibratory moments and shear forces, which simultaneously exist at the vertex of corner angle exceeding 180$^{\circ}$. The first set guarantees convergence to the exact frequencies as sufficient terms are taken. The second set represents the corner singularities, and accelerates convergence substantially. Numerical results are obtained for completely free sectorial plates. Accurate frequencies are presented for a wide spectrum of vertex angles (90$^{\circ}$, 180$^{\circ}$, 270$^{\circ}$, 300$^{\circ}$, 330$^{\circ}$, 350$^{\circ}$, 35 5$^{\circ}$,and 359$^{\circ}$)and thickness ratios.tios.

• East Asian mathematical journal
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• 제23권1호
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• pp.83-101
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• 2007

In this paper the concept of somewhat pairwise fuzzy continuous functions and somewhat pairwise fuzzy open functions are introduced. Some interesting properties of these functions are investigated besides giving some characterizations of these functions.

• Kyungpook Mathematical Journal
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• 제58권3호
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• pp.507-517
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• 2018

In this article, we introduce a new integral operator involving normalized Bessel functions of the first kind and we obtain a set of sufficient conditions for univalence. Our results contain some interesting corollaries as special cases. Further, as particular cases, we improve some of the univalence conditions proved in [2].

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2000년도 추계학술대회 학술발표 논문집
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• pp.259-262
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• 2000

In this paper, an Adaptive neuro-fuzzy Inference system(ANFIS) using fuzzy min-max network(FMMN) is proposed. Fuzzy min-max network classifier that utilizes fuzzy sets as pattern classes is described. Each fuzzy set is an aggregation of fuzzy set hyperboxes. Here, the proposed method transforms the hyperboxes into gaussian menbership functions, where the transformed membership functions are inserted for generating fuzzy rules of ANFIS. Finally, we applied the proposed method to the classification problem of iris data and obtained a better performance than previous works.