• Proceedings of the Korean Ceranic Society Conference
• /
• 2003.10a
• /
• pp.57.1-57
• /
• 2003

• The Bulletin of The Korean Astronomical Society
• /
• v.34 no.1
• /
• pp.177.2-177.2
• /
• 2009

• Proceedings of the Korean Information Science Society Conference
• /
• 2006.10b
• /
• pp.372-377
• /
• 2006

유비쿼터스 컴퓨팅 시대의 도래와 시맨틱 웹에 대한 관심이 높아짐에 따라 관련 기술인 온톨로지와 이를 이용한 추론 기술에 대한 요구가 증가하고 있다. 따라서, 추론이 가능한 시맨틱 웹 기반의 모델링과 추론에 대한 연구가 필요하다. 모델링을 위해 사용되는 OWL-DL과 임의의 사용자 규칙을 표현하는 SWRL은 각각 W3C의 표준안으로서, 유비쿼터스 컴퓨팅 환경에 효율적으로 자동적인 개인화 서비스[1][2]를 제공하는데 있어서 적합하다. 그러나 OWL-DL과 SWRL의 단순한 결합은 질의응답(Query Answering)에 대한 처리가 비결정 가능한(undecidable) 문제를 야기한다. 본 논문에서는, 비결정가능성 문제의 원인인 무한반복의 가능성을 제거하기 위한 블록(blocking) 방법을 제안한다. OWL-DL이 지닌 서술논리(Description Logic)의 표현력을 유지하고, 그에 따른 추론의 질적인 성능을 유지하는 범위에서 블록방법을 사용하여 결정 가능한 질의응답을 수행하는데 궁극적인 목적을 두고 있다. OWL-DL의 TBox에 위치하는 존재 정량자(Existential Quantifier)를 대체하고 ABox에 삽입하여, 무한반복의 가능성을 없애는 해결 방법을 제시한다. 실험은 비결정가능성 문제를 DL-Safe 규칙을 통해 해결한 KAON2와 비교하여 진행한다.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.30 no.1
• /
• pp.87-94
• /
• 2017

Reliability analysis(RA) and Reliability-based design optimization(RBDO) require statistical modeling of input random variables, which is parametrically or nonparametrically determined based on experimental data. For the parametric method, goodness-of-fit (GOF) test and model selection method are widely used, and a sequential statistical modeling method combining the merits of the two methods has been recently proposed. Kernel density estimation(KDE) is often used as a nonparametric method, and it well describes a distribution function when the number of data is small or a density function has multimodal distribution. Although accurate statistical models are needed to obtain accurate RA and RBDO results, accurate statistical modeling is difficult when the number of data is small. In this study, the accuracy of two statistical modeling methods, SSM and KDE, were compared according to the number of data. Through numerical examples, the RA results using the input models modeled by two methods were compared, and appropriate modeling method was proposed according to the number of data.

• The Journal of Information Technology
• /
• v.6 no.3
• /
• pp.1-10
• /
• 2003

This paper is concerned with a power line channel modeling for the more fast and efficiently power line communication experiment. A capacitor load channel simulator is a essential equipment in the power line modem development for in-house network. We accomplished a channel modelling by the frequency response method about the total 298 capacitor load channels. This channel data is acquired by the capacitor load simulator modeling a real power line channel environment. When the experiment results acquired from the capacitor load simulator were compared with the result from a channel filter, we confirmed to substitute capacitor load experiments on the actual power line communication without big error.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2001.10b
• /
• pp.1611-1614
• /
• 2001

현재 웹 상에서 진행되는 교육용 컨텐츠들은 날로 인기가 놀아지고 그에 부응하여 많은 교육용 웹 애플리케이션들이 만들어지고 있다. 그러나 증가되고 있는 컨텐츠 개발을 위한 기술과 도구들은 빠른 발전을 이루고 있는 반면 개발 프로세스에 대해서는 관심을 두지 않았다. 분석과 설계가 결핍된 상태에서 개발된 웹 애플리케이션은 품질 저하와 생산성 저하 등의 부정적인 파급효과를 가지게 된다. 따라서 교육용 웹 애플리케이션은 개발 초기에 적절한 모델링이 필요하다. 본 연구에서는 소프트웨어 공학 기술을 컨텐츠 개발에 적용하는 접근 방법을 사용하여 웹 애플리케이션 설계를 돕는 메커니즘을 제공하고 웹 기반의 맞춤형 교육을 위한 컨텐츠 모델링 방법에 관하여 논의한다. 웹 애플리케이션의 구성요소의 기호와 의미를 정립하고 교육용 컨텐츠의 구조를 정의, 분석한 후 웹 기반 시스템 모델링을 위한 구조로 재정의 한다. 적절한 모델링 과정을 거쳐 교육용 웹 애플리케이션을 개발함으로써 교육용 웹 컨텐츠의 체계적인 개발 및 관리 지원이 가능하게 된다.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.10 no.5
• /
• pp.432-441
• /
• 2000

This paper deals with the fuzzy modeling for the complex and uncertain nonlinear systems, in which conventional and mathematical models may fail to give satisfactory results. Genetic algorithm has been used to identifY parameters and structure of fuzzy model because it has the ability to search optimal solution somewhat globally. The genetic algorithm, however, has a problem, which optimization process can be premature convergence in the case of lack of genetic divergence of population. Virus- evolutionary genetic algorithm(VEGA) could be a strategy against this local convergence. Therefore, we use VEGA for fuzzy modeling. In this method, local information is exchanged in population so that population can sustain genetic divergence. finally, to prove the theoretical hypothesis, we provide numerical examples to evaluate the feasibility and generality of fuzzy modeling using VEGA.

• Journal of the Society of Naval Architects of Korea
• /
• v.29 no.2
• /
• pp.30-37
• /
• 1992

Since a ship is a complex steel construction which consists of sculptured surfaces and inner surface members, a high technique of information modeling is indispensable to describe the form of hull surface and steel structure members consistently. A model contains both topological and geometrical information of the structural members. Therefore, the hull form should be represented by the wireframe of surface model so that the accuracy in each design stage is satisfied. The structural members like plane surfaces, stiffeners and the relations between such members are to be described systematically in data base. A collection of the data stored in database is a model to be built. The model will be used not only to generate the drawings and documents for ship design and production but also to interconnect other systems such as compartmentation, outfitting, piping, etc. Computer graphics is adopted of the visualization of model.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.10 no.1
• /
• pp.91-104
• /
• 2008

In tunnels, safety factor concept has been suggested to estimate their stability quantitatively. It is merely limited in the framework of mechanical analysis. However safety factor concept has not been applied in hydro-mechanical coupled analyses due to their modelling complexity. Recently studies on this topic are being actively made. In this study, induced drainage modelling methods for hydro-mechanical coupled analyses are compared and analyzed to estimate safety factor of a subsea tunnel exactly. To this end, methods both controlling hydraulic characteristic of shotcrete and using a drainage well are considered. Sensitivity analysis were carried out on rock class, thickness of shotcrete, and hydraulic properties of rock mass. As the results of this study, it turned out that the induced drainage modelling using a drainage well would give more reliable results than that of controlling hydraulic characteristic of shotcrete in estimating tunnel stability in hydro-mechanical coupled analyses.

• Journal of KIISE:Software and Applications
• /
• v.34 no.3
• /
• pp.179-195
• /
• 2007

Traditional software development method is not suitable for Web application development because of characteristics of Web application such as frequent requirements change, different architectures and models and quick-to-market delivery. In this paper we propose a Web application development method adaptable to requirements change while we systematically model Web application using extended UML model. The metamodel is independent to specific languages and technologies because we define the metamodel using extended UML model. Proposed process is described by SPEM(Software Process Engineering Metamodel) profile. A process supporting tool execute and customize process. To model Web applications systematically and effectively, a navigation modeling and a component communication modeling tools are provided. In a case study, we show the usefulness of our process and model.