• 한국수학사학회지
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• 제18권3호
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• pp.79-90
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• 2005

일차대전 전의 프랑스 수학사는 괄목할 만 하였으나 일차대전 후 프랑스는 독일과 영국에 비하여 완전히 진공 상태였다. 이에 젊은 프랑스 수학자들은 독일로부터 크게 자극을 받아 Bourbaki학파를 생성하고 때마침 사회적으로나 정치적으로 생성된 구조주의(structuralism)와 발맞추어 수학의 구조적 접근을 시도하였다. 우리는 Bourbaki의 생성 과정과 발전 단계를 알아보고 그 구성원들과 그들이 심혈을 기울여 집필한 책들, 그리고 업적에 대하여 조사한 후 Bourbaki학파의 쇠퇴 과정을 살펴 본다.

• 한국수학사학회지
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• 제20권2호
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• pp.1-18
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• 2007

19세기 조선(朝鮮) 산학자(算學者) 이상혁(李尙爀), 남병길(南秉吉)은 구장산술(九章算術), 술리정온(數理精蘊) 등을 연구한 후 송(宋), 원대(元代)의 수학을 구조적으로 연구하여 조선(朝鮮) 산학(算學)이 크게 발전하는 전기를 마련하였다. 이 논문에서는 남병길(南秉吉)의 저서 집고연단(輯古演段)과 무이해(無異解)를 조사하여 그의 방정식논(方程式論)을 연구한다. 남병길(南秉吉)은 이상혁(李尙爀)과 공동 연구를 통하여 송(宋), 원대(元代)와 서양(西洋) 수학(數學)의 방정식논(方程式論)을 함께 구조적으로 정리하였다.

• 세라미스트
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• 제22권4호
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• pp.350-356
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• 2019

Recently, transition metal dichalcogenide (TMDC) monolayers have been the subject of research exploring the physical phenomenon generated by low dimensionality and high symmetry. One of the keys to understanding new physical observations is the electronic band structure of 2D TMDCs. Angle-resolved photoelectron spectroscopy (ARPES) is, to this point, the best technique for obtaining information on the electronic structure of 2D TMDCs. However, through ARPES research, obtaining the long-range well-ordered single crystal samples always proves a challenging and obstacle presenting issue, which has been limiting towards measuring the electronic band structures of samples. This is particularly true in general 2D TMDCs cases. Here, we introduce the approach, with a mathematical framework, to overcome such ARPES limitations by employing the high level of symmetry of 2D TMDCs. Their high symmetry enables measurement of the clear and sharp electronic band dispersion, which is dominated by the band dispersion of single-crystal TMDCs along the two high symmetry directions Γ-K and Γ-M. In addition, we present two important studies and observations for the direct measuring of the exciton binding energy and charge transfer of 2D TMDCs, both being established by the above novel approach.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 D
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• pp.2192-2195
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• 2002

Even though, tanks are used at the many industry plants, it is very difficult to control the tank level without any overflow and shortage; moreover, cause of its complication of dynamics and nonlinearity, it's impossible to realize the accurate control using the mathematical model which can be applied to the various operation modes. However, the sliding mode controller(SMC) is known as having the robust variable structures for the nonlinear control systems with the parametric perturbations and with the sudden disturbances. It's difficult to find SMC's parameters, and SMC is bring chattering which injures actuator and increases error. In this paper, Genetic Aloglism based Fuzzy Sliding Mode Controller(GA-FSMC) for the precise control of the coupled tank level was proposed. Genetic Algolism and Fuzzy logic are adapted to find SMC's parameters and reduce the chattering. The simulation result is shown that the tank level could be satisfactorily controlled with less overshoot and steady-state error by the proposed GA-FSMC.

• Smart Structures and Systems
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• 제17권4호
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• pp.611-629
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• 2016

This study presents a new approach of surrogate modeling for time-consuming finite element analysis. A surrogate model is widely used to reduce the computational cost under an iterative computational analysis. Although a variety of the methods have been widely investigated, there are still difficulties in surrogate modeling from a practical point of view: (1) How to derive optimal design of experiments (i.e., the number of training samples and their locations); and (2) diagnostics of the surrogate model. To overcome these difficulties, we propose a sequential surrogate modeling based on Gaussian process model (GPM) with self-adaptive sampling. The proposed approach not only enables further sampling to make GPM more accurate, but also evaluates the model adequacy within a sequential framework. The applicability of the proposed approach is first demonstrated by using mathematical test functions. Then, it is applied as a substitute of the iterative finite element analysis to Monte Carlo simulation for a response uncertainty analysis under correlated input uncertainties. In all numerical studies, it is successful to build GPM automatically with the minimal user intervention. The proposed approach can be customized for the various response surfaces and help a less experienced user save his/her efforts.

• Asia pacific journal of information systems
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• 제10권2호
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• pp.51-69
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• 2000

Recently, as business problems become more complicated and require more precise quantitative results, large-scale model management systems are increasingly in demand for supporting the decision-making activities. In addition, as distributed computing over networks gains popularity, departmental computing systems are gradually adopted in an organization to facilitate collaboration of geographically dispersed multiple departments. In departmental collaborative model management systems, multiple departments share common models but approach them with different user-views depending on their departmental needs. Moreover, the shared models become evolved as their structures and the corresponding data sets change due to the dynamic nature of the operating environment and the inherent uncertainty associated with the problems. In such capacity, providing the multiple departmental users with synchronized and consistent views of the models is important to improve the overall productivity. In this paper, we propose a collaborative model management framework for coordinating model change and automatic user-view update in a departmental computing environment. To do so, we describes changes in the model and their effects occurred in departmental model management environments and identifies the constructs and processes for maintaining the consistency between a shared model and its departmental user-views. Especially, in this framework, generic model concept was adopted for accommodating diverse mathematical models in a uniform way in a modelbase and object-oriented database management systems(ODBMS) for combining the model management constructs and automatic user-view update mechanisms in a single formalism. A prototype object-oriented modeling environment was developed using an ODBMS called ObjectStore and $C^{++}$ programming language on Windows NT.

• Bulletin of the Korean Chemical Society
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• 제30권8호
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• pp.1783-1792
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• 2009

Although overlapping resonances have been studied extensively in conventional resonance theories, there have not been many studies on them in multichannel quantum defect theories (MQDT). In MQDT, overlapping resonances occur between the channels instead of states, which pose far greater difficulty. Their systematic treatment was obtained for cases involving degenerate closed channels by applying our previous theory, which decouples background scattering from the resonance scattering in the MQDT formulation. The use of mathematical theory on con-diagonalization and con-similarity was essential for handling the non-Hermitian symmetric complex matrix. Overlapping resonances in rare gas spectra of Ar, Kr and Xe were analyzed using this theory and the results were compared with the ones of the previous alternative parameterizations of MQDT which make the open-open part $K^{oo}$ and closed-closed part $K^{cc}$ of reactance submatrices zero. The comparison revealed that separation of background and resonance scatterings achieved in our formulation in a systematic way was not achieved in the representation of $K^{oo}\;=\;0\;and\;K^{cc}$ = 0 when overlapping resonances are present.

• 정보통신설비학회논문지
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• 제2권2호
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• pp.46-58
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• 2003

인간이 원하는 감성에 따라 환경 요소값이 변하고 이로 인해 변하는 현재 환경 안에서 인간이 자신의 최적의 쾌적감을 느끼도록 하는 것이 바로 감성공학을 응용한 제품 개발의 주목적이라고 할 수 있다. 이를 위해서는 제품 개발 이전에 인간 감성에 대한 평가와 분석 과정이 선행되어져야 한다. 본 논문은 쾌적감성과 감각의 구조를 분석한 연구결과에 대하여 신경망이론을 적용하여, 수학적으로 표현하기 어려운 인간의 쾌적감성과 감각의 관계성을 학습시킨다. 또한, 가변적 실내 환경에서 인간의 감성 요구치에 대해 환경을 변화시킴으로써 인간이 스스로 원하는 최적의 쾌적감을 느낄 수 있는 실내 환경을 모의로 구현해 볼 수 있는 시뮬레이터을 제시한다.

• 한국정보처리학회논문지
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• 제2권3호
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• pp.364-373
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• 1995

본 논문은 동적 자료구조의 확률론적 운영방식의 설계와 그 성능분석의 이론적 접근 방법을 제시한다. 즉 m개의 셀로서 구성된 일련의 연속된 블록에 두 개의 스택 을 할당하여 공유하는 시스템의 확률적 운용방식의 효율성을 해석적 방법에 의한 성 능분석을 통하여 그 결과를 제시한다. 특히 스택 원소의 삽입과 제거는 스택의 현재 의 크기에 따라 빈도를 달리하는 방식을 제안한다. 따라서 두 스택의 충돌까지 스택 조작 횟수의 평균과 분산등 통계적 특성을 희소 사건 확률 계산이론에 의하여 m$\longrightarrow$$\infty$ 일 때 점근적 결과를 제시한다. 또한 유한상태기계, 컴퓨터 및 정보 시스템의 성능 분석에 응용할 수 있는 보다 일반적인 방법을 고찰한다.

• Structural Engineering and Mechanics
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• 제23권1호
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• pp.29-42
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• 2006

This paper describes the design scheme of the three-dimensional structures based on the concept of the cellular automata simulation. The cellular automata simulation is performed according to the local rule. In this paper, the local rule is derived in the mathematical formulation from the optimization problem. The cell density is taken as the design variable. Two objective functions are defined for reducing the total weight of the structure and obtaining the fully stressed structure. The constraint condition is defined for defining the local rule. The penalty function is defined from the objective functions and the constraint condition. Minimization of the penalty function with respect to the design parameter leads to the local rule. The derived rule is applied to the design of the three-dimensional structure first. The final structure can be obtained successfully. However, the computational cost is expensive. So, in order to reduce the computational cost, the material parameters $c_1$ and $c_2$ and the value of the cell rejection criterion (CRC) are changed. The results show that the computational cost depends on the parameters and the CRC value.