• 대한기계학회논문집A
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• 제33권8호
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• pp.786-792
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• 2009

Topology optimization is to find the optimal material distribution of the specified design domain minimizing the objective function while satisfying the design constraints. Since the genetic algorithm (GA) has its advantage of locating global optimum with high probability, it has been applied to the topology optimization. To guarantee the structural connectivity, the concept of compliance pattern is proposed and to improve the convergence rate, small number of population size and variable probability in genetic operators are incorporated into GA. The rank sum weight method is applied to formulate the fitness function consisting of compliance, volume, connectivity and checkerboard pattern. To substantiate the proposed method design examples in the previous works are compared with respect to the number of function evaluation and objective function value. The comparative study shows that the compliance pattern based GA results in the reduction of computational cost to obtain the reasonable structural topology.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1998년도 추계학술대회
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• pp.263-264
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• 1998

In this paper, we present the result of feature points recognition and classification of radial pulse by the shape of pulse wave. And we analyze radial pulse in frequency domain. The recognition algorithm use the method which runs in parallel with both the data of ECG and differential pulse simultaneously to recognize the feature points. Also fie specified 3-time elements of pulse wave as main parameters for diagnosis and measured them by execution of algorithm, then we classify the shape of radial pulse by existence and position of feature points. lastly we execute frequency analysis on the feature points and get the power spectrum of radial pulse.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제9권1호
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• pp.63-77
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• 2005

The Dirichlet-Neumann problem for the dissipative Helmholtz equation in a connected plane region bounded by closed curves and containing cuts is studied. The Neumann condition is given on the closed curves, while the Dirichlet condition is specified on the cuts. The existence of a classical solution is proved by potential theory. The integral representation of the unique classical solution is obtained. The problem is reduced to the Fredholm equation of the second kind and index zero, which is uniquely solvable. Our results hold for both interior and exterior domains.

• 대한전기학회논문지
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• 제39권9호
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• pp.934-943
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• 1990

There are no turn-on losses in the series Resonant Converter which operates above the resonance frequency, and the commutation stress on the switched component is low. For a given Series Resonant Converter with specified load resistance, the output voltage is a function of the operation frequency. This paper describes the static and dynamic characteristic analysis of the Series Resonant DC to DC Converter, which is operating above the resonant frequency, with frequency control. For the analysis method, state plane technique is adopted, and the circuit operation is defined from normalized switching frequency, Fsn. Under this condition, circuit performance is analyzed ideally. The validity of the proposed analysis is verified by comparing with experimental results, the stability of the converter is confirmed against small variations around the operating point by conventional frequency domain analysis, and the stress quantity added to switch component is shown.

• 한국정보과학회 언어공학연구회:학술대회논문집(한글 및 한국어 정보처리)
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• 한국정보과학회언어공학연구회 2009년도 제21회 한글 및 한국어 정보처리 학술대회
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• pp.237-241
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• 2009

본 논문에서는 도메인별 병렬 말뭉치를 이용하여 해당 도메인에 특화된 한영 대역쌍을 Moses Toolkit을 이용하여 자동 추출하였다. 이렇게 추출된 대역쌍은 도메인 특화 자동 번역 시스템의 번역 사전으로 사용하기에는 많은 오류가 포함되어 있기 때문에, 본 논문에서는 이를 효율적으로 제거할 수 있는 식을 제안하였다. 본 논문에서 제안한 식으로 오류를 제거한 결과, 임계값 0.5를 기준으로 추출된 한영 대역쌍이 1,098개였고, 이는 실험에 사용한 기업 분야 병렬 말뭉치 42,200문장 중에서 29,292문장(69.4%)에 영향을 주었다. 자동으로 추출한 도메인 특화 번역 지식을 기존 자동 번역 시스템의 번역 지식에 적용한 결과 BLEU가 0.0054 향상되었다.

• 전자공학회논문지A
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• 제33A권4호
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• pp.47-56
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• 1996

For the implementation of callcontrol software, it will be shown how to divide problems into dimain and also presents methodologies to specify domains according to the object-orented analysis techniques. Domains is specified by the set of related objects as shown in call control examples. Events and conditons are able to be transformed into system invariant so that is possible to figure out the relationship between domains and those concludes that the software requirements specification can be established for the design and implementation. Relationships existing between domains can be formalized so as to verify software requirements.

• 한국정보처리학회논문지
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• 제7권5S호
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• pp.1629-1637
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• 2000

With wide spending the Internet and Web techniques, we have recognized the necessary and commercial-value of electronic commerce system. Electronic commerce(EC) means the whole economical activities based on electronic medium. Both scalability and flexibility are fundamental attributes of EC system and interoperability among heterogeneous systems must be supported. So, for successful a developing of EC system, it is necessary to apply the CBD (Component Based Development) based on component assembling and customization. In this paper, we propose the method for identifying and specifying the components to construct the component based electronic commerce system. To do, we define the component/system architecture specified on EC domain, identified and classified the EC components with hierarchy relationship. Also, we suggested the specification notation and some examples.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.468-473
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• 2004

New reliability-based topology optimization method is proposed by utilizing single-loop single vector approach, which approximate searching the most probable point in the probabilistic design domain analytically, to reduce the time cost and dealing with several constraints to handle practical design requirements. To examine uncertainties in the topology design of a structure, the modulus of elasticity of the material and applied loadings are considered as probabilistic design variables. The results of design examples show that the proposed method provides efficiency curtailing the time for the optimization process and accuracy satisfying the specified reliability.

• 대한기계학회논문집A
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• 제29권1호
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• pp.22-29
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• 2005

A material cloud method, which is a new topology optimization method, is presented. In MCM, an optimal structure can be found out by manipulating sizes and positions of material clouds, which are lumps of material with specified properties. A numerical analysis for a specific distribution of material clouds is carried out using fixed background finite element mesh. Optimal material distribution can be element-wisely extracted from material clouds' distribution. In MCM, an expansion-reduction procedure of design domain for finding out better optimal solution can be naturally realized. Also the convergence of material distribution is faster and well-defined material distribution with fewer intermediate densities can be obtained. In addition, the control of minimum-member sizes in the material distribution can be realized to some extent. In this paper, basic concept of MCM is introduced, and formulation and optimization results of MCM are compared with those of the traditional density distribution method(DDM).

• Earthquakes and Structures
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• 제3권3_4호
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• pp.383-411
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• 2012

The objective of the present paper is to review and implement the most recent developments in the Spectral Element Method (SEM), as well as improve aspects of its implementation in the study of wave propagation by numerical simulation in elastic unbounded domains. The classical formulation of the method is reviewed, and the construction of the mass matrix, stiffness matrix and the external force vector is expressed in terms of matrix operations that are familiar to earthquake engineers. To account for the radiation condition at the external boundaries of the domain, a new absorbing boundary condition, based on the Perfectly Matched Layer (PML) is proposed and implemented. The new formulation, referred to as the Multi-Axial Perfectly Matched Layer (M-PML), results from generalizing the classical Perfectly Matched Layer to a medium in which damping profiles are specified in more than one direction.