• International Journal of Fuzzy Logic and Intelligent Systems
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• 제11권3호
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• pp.149-152
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• 2011

In this paper, we obtain common fixed point theorem for common property(E.A.) and weakly compatible functions in intuitionistic fuzzy metric space.

• 한국CDE학회논문집
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• 제12권3호
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• pp.220-232
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• 2007

Current geometric modeling and analysis are commonly based on B-Rep modeling and a finite elements method respectively. Furthermore, it is difficult to represent an object whose material property is heterogeneous using the B-Rep method because the B-Rep is basically used for homogeneous models. In addition, meshes are required to analyze a property of a model when the finite elements method is applied. However, the process of generating meshes from B-Rep is cumbersome and sometimes difficult especially when the model is deformed as time goes by because the topology of deforming meshes are changed. To overcome those problems in modeling and analysis including homogeneous and heterogeneous materials, we suggest a unified modeling and analysis method based on implicit representation of the model using R-function which is suggested by Rvachev. For implicit modeling of an object a distance field is approximated and blended for a complex object. Using the implicit function mesh-free analysis is possible where meshes are not necessary. Generally mesh-free analysis requires heavy computational cost compared to a finite elements method. To improve the computing time of function evaluation, we utilize GPU programming. Finally, we give an example of a simple pipe design problem and show modeling and analysis process using our unified modeling and analysis method.

• Journal of applied mathematics & informatics
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• 제31권5_6호
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• pp.795-812
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• 2013

The merit function arises from the development of the solution methods for the complementarity problems defined over the cone of non negative real vectors and has been well extended to the complementarity problems defined over the symmetric cones. In this paper, we focus on the extension of the merit functions including the gap function, the regularized gap function, the implicit Lagrangian and others to the complementarity problems defined over the nonsymmetric matrix cone. These theoretical results of this paper suggest new solution methods based on unconstrained and/or simply constrained methods to solve the matrix cone complementarity problems (MCCP).

• 대한수학회논문집
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• 제24권1호
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• pp.41-55
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• 2009

A general common fixed point theorem for two pairs of weakly compatible mappings using an implicit function is proved without any continuity requirement which generalizes the result due to Popa [20, Theorem 3]. In process, several previously known results due to Fisher, Kannan, Jeong and Rhoades, Imdad and Ali, Imdad and Khan, Khan, Shahzad and others are derived as special cases. Some related results and illustrative examples are also discussed. As an application of our main result, we prove an existence theorem for the solution of simultaneous Hammerstein type integral equations.

• 지식경영연구
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• 제2권1호
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• pp.65-81
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• 2001

The aim of this study is classify knowledge work style management for knowledge management. It is based on the knowledge creation model of Nonaka by subdividing types of knowledge workers. It was designed to create a model for application to the actual environment of management. Nonaka suggested the process of socialization, externalization, combination, internalization that the knowledge of a person creates new knowledge through the interaction of implicit knowledge and explicit knowledge. This research demonstrated that knowledge worker of 16 forms by applying SECI model to the main function and the subordinate functions again. This study aims at achieving a higher outcome by applying the ability of existing knowledge worker to subdivided expert field efficiently. Suggested styles of knowledge worker in this research are classified into craftsman style, pragmatic style, combination style, developed style knowledge worker who creates knowledge by selecting socialization as the function and again by selecting externalization combination, internalization as subordinate functions. And they were classified into creation style, insight style, strategy style according to practical application worker and function which is selecting externalization as the main function and socialization as the subordinate functions. They were classified into future style, innovation style, analysis style, judgement style knowledge worker who are selecting combination as the main function and experiment style, intuition style, research style, learning style worker who are selecting internalization as the main function. They suggested the characteristics and cases of each type.

• Structural Engineering and Mechanics
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• 제85권3호
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• pp.369-379
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• 2023

Reliability-Based Design Optimization (RBDO) is an appropriate framework for obtaining optimal designs by taking uncertainties into account. Large-scale problems with implicit limit state functions and problems with discrete design variables are two significant challenges to traditional RBDO methods. To overcome these challenges, this paper proposes a hybrid method to perform RBDO of structures that links Firefly Algorithm (FA) as an optimization tool to advanced (finite element) reliability methods. Furthermore, the Genetic Algorithm (GA) and the FA are compared based on the design cost (objective function) they achieve. In the proposed method, Weighted Simulation Method (WSM) is utilized to assess reliability constraints in the RBDO problems with explicit limit state functions. WSM is selected to reduce computational costs. To performing RBDO of structures with finite element modeling and implicit limit state functions, a First-Order Reliability Method (FORM) based on the Direct Differentiation Method (DDM) is utilized. Four numerical examples are considered to assess the effectiveness of the proposed method. The findings illustrate that the proposed RBDO method is applicable and efficient for RBDO problems with discrete and continuous design variables and finite element modeling.

• 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.

• 한국심리학회지 : 문화 및 사회문제
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• 제18권4호
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• pp.463-479
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• 2012

암묵적 연합검사는 연구참가자의 내면적인 태도를 측정하고, 미래의 행동을 예측하는데 효과적인 방법으로 알려져 있다. 본 연구에서는 암묵적 연합검사를 토대로 한 개인의 창의성에 대한 무의식적인 부정적 태도가 창의적인 과정에 유리하다고 알려져 있는 전체지각과 어떤 관계에 있는지를 분석하고자 하였다. 이를 위해 실험에서는 대학생 참가자에게 창의성/실용성과 긍정/부정단어들을 각각 짝지어 제시한 후, 창의성-긍정단어에 대한 반응시간과 창의성-부정단어에 대한 반응시간의 차이를 통해 암묵적 태도를 측정했다. 그 이후 참가자들은 전체유형 혹은 부분유형으로 나타나는 글자에 대해 신속하게 반응하는 네이본 과제를 수행했다. 그 결과, 창의성에 대한 암묵적 편견이 적은 참가자집단에서 전체지각의 반응시간이 부분지각의 반응시간보다 더 빠르게 나타났으며, 전체지각의 이득이 나타났다. 반면 창의성에 대한 암묵적인 편견이 높은 참가자집단에서는 전체지각과 부분지각의 유의한 차이가 관찰되지 않았으며, 전체지각의 이득이 사라졌다. 이 결과는 한 개인이 갖고 있는 창의성에 대한 암묵적 편견은 자신의 창의적 과정과 부적 관계에 있음을 보여주며, 창의성의 예측에서 암묵적인 태도 측정의 중요성을 시사한다.

• 한국컴퓨터그래픽스학회논문지
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• 제2권1호
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• pp.31-38
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• 1996

주어진 제약조건을 만족시키는 부드러운 곡선과 곡면을 찾으려는 많은 시도와 노력이 계속되어 왔고, 보간과 근사 이론의 발달과 컴퓨터의 등장은 이러한 요구를 충족시키기 위한 중요한 역할을 하게 되었다. 곡선과 곡면을 모델링하는 지금까지의 많은 연구가 매개변수에 의한 방법에 집중되어 왔으나 모델링 시스템에서 물체를 표현할 때, 몇가지 문제에 직면하게 되었다. 따라서 최근에는 다항 방정식의 형태로 표현되는 음대수 곡선, 곡면에 대한 연구에 많은 관심을 갖게 되었고, 상대적으로 낮은 차수를 갖는 곡면을 만들 수 있게 되었다. 본 논문에서는 음대수 함수를 이용하여 표현된 곡선 및 곡면에 대한 기하학적 성질과 수학적인 계산 과정을 정리하고 이런 기본 배경을 바탕으로 여러 가지 방법을 이용하여 사용자가 원하는 곡선과 대칭성을 갖는 회전체 곡면을 쉽게 설계할 수 있는 도구의 구현에 대해 설명한다. 이렇게 구현된 회전체는 CAD나 CAM과 같은 실용적인 분야에서 대칭성을 갖는 복잡한 물체를 설계할 때, 중요한 역할을 할 수 있을 것이다.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2003년도 춘계 학술대회 학술발표 논문집
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• pp.247-250
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• 2003

Due to the increasing use of very large databases, mining useful information and implicit knowledge from databases is evolving. However, most conventional data mining algorithms identify the relationship among features using binary values (TRUE/FALSE or 0/1) and find simple If-THEN rules at a single concept level. Therefore, implicit knowledge and causal relationships among features are commonly seen in real-world database and applications. In this paper, we thus introduce the mechanism of mining fuzzy association rules and constructing causal knowledge base form database. Acausal knowledge base construction algorithm based on Fuzzy Cognitive Map(FCM) and Srikant and Agrawal's association rule extraction method were proposed for extracting implicit causal knowledge from database. Fuzzy association rules are well suited for the thinking of human subjects and will help to increase the flexibility for supporting users in making decisions or designing the fuzzy systems. It integrates fuzzy set concept and causal knowledge-based data mining technologies to achieve this purpose. The proposed mechanism consists of three phases: First, adaptation of the fuzzy membership function to the database. Second, extraction of the fuzzy association rules using fuzzy input values. Third, building the causal knowledge base. A credit example is presented to illustrate a detailed process for finding the fuzzy association rules from a specified database, demonstration the effectiveness of the proposed algorithm.