• Journal of Advanced Marine Engineering and Technology
• /
• 제19권2호
• /
• pp.67-80
• /
• 1995

In order to control systems which are dominantly subjected to modeling errors and uncertainties, control strategies must deal with the effect of modeling errors and uncertainties. Since most of control methods based on system mathematical model, such as LQG/LTR method, have been developed mainly focused on stability robustness, they can not smartly improve the transient response disturbed by modeling errors and/or uncertainties. In this research, a fuzzy PID control method is suggested, which can stably improve the transient responses of systems disturbed by modeling errors as well as systems not entirely using mathematical models. So as to assure the effectiveness of suggested control method, computer simulations are accomplished for some example systems, through the comparison of transient responses.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2002년도 추계학술대회논문초록집
• /
• pp.331.2-331
• /
• 2002

A modeling method for cantilever beams undergoing axially oscillating motion is presented in this paper. Hybrid deformation variables are employed for the modeling method. Frequency response characteristics are investigated with the modeling method. It is shown that the geometric nonlinear effects of stretching and curvature play important roles to accurately predict the dynamic response. (omitted)

• 한국수학교육학회지시리즈D:수학교육연구
• /
• 제15권2호
• /
• pp.181-196
• /
• 2011

In mathematical modeling tasks, where students are exposed to model-eliciting for real and open problems, students are supposed to formulate and use a variety of mathematical skills and tools at hand to achieve feasible and meaningful solutions using appropriate problem solving strategies. In contrast to problem solving activities in conventional math classes, math modeling tasks call for varieties of mathematical ability including mathematical creativity. Mathematical creativity encompasses complex and compound traits. Many researchers suggest the exhaustive list of criterions of mathematical creativity. With regard to the research considering the possibility of enhancing creativity via math modeling instruction, a quantitative scheme to scale and calibrate the creativity was investigated and the assessment of math modeling activity was suggested for practical purposes.

• 대한수학교육학회지:학교수학
• /
• 제7권3호
• /
• pp.303-318
• /
• 2005

학생들이 자신의 문제 상황을 해결하기 위하여 수학을 이용하고, 그를 통해 수학적 지식을 학습할 수 있다면, 이것은 학생들이 수학의 유용성과 가치를 깨닫게 하는 수학교육이 될 것이다. 본 연구는 학생들이 문제해결을 통하여 수학을 학습할 수 있도록 지도하기 위해, 여러 교과에서 관심을 두고 있는 문제 중심 학습을 고찰하고 그것을 수학 교과에서 수학적 모델링으로 적용하려 시도했다. 수학적 모델링을 적용한 수업 모형을 제안하고, 학생들을 실제로 지도한 예시를 들어, 형식적이고 위계적인 학문으로서의 수학에 모델링을 도입하여 문제 중심 학습을 실현할 수 있음을 보이려 했다.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2002년도 추계학술대회 논문집
• /
• pp.954-957
• /
• 2002

The objective of design process modeling is a systematic support of rapid redesign process fur a modified input data. The design process modeling is realized by storing key parameters or geometric entities used in the intermediate design steps and reusing them for change of the designed parts or assemblies according to the modified input. In this paper, we adopted and implemented the design process modeling approach to our injection mold design system developed based on the Unigraphics system. It was proved that the productivity of mold redesign process is raised highly by introducing the design process modeling technique mold design system.

• 한국신뢰성학회:학술대회논문집
• /
• 한국신뢰성학회 2000년도 춘계학술대회 발표논문집
• /
• pp.223-230
• /
• 2000

This work aims to develop modeling methodology of machine part reliability. The reliability model is to be used for predicting and improving reliability in planning and design processes of products. In order to develop the reliability model of machine parts, the functions and interactions of sub-units of machine parts are analyzed first and function network is constructed. Using the function network, function block diagram is developed, which can be the basis for deriving reliability block diagram. Modeling of machine part reliability has not been widely studied since the reliability modeling of machine parts requires understanding of the functions and failures of their components in several viewpoints. This work tries to find general methodology of reliability modeling and proposes a framework for reliability improvement during machine part development.

• 한국CDE학회논문집
• /
• 제6권4호
• /
• pp.254-262
• /
• 2001

It is not possible to exchange parametric information of CAD (Computer Aided Design) models based on the current version of STEP (Standard leer the Exchange of Product model data). The design intent can be lost during the STEP transfer of CAD models. The ISO Parametrics Group has proposed the SMCH (Solid Model Construction History) schema in June 2000 that includes structures fur exchange of parametric information. This paper proposes the macro parametric approach that is intended to provide capabilities to transfer parametric information. In this approach, CAD models are exchanged in the form of macro files. The macro file contains user commands which are used in the modeling phase. To exchange CAD models using the macro parametric approach, modeling commands of commercial CAD systems are analyzed. Those commands are classified by the grouping method suggested by Bill Anderson. As a neutral file format, a standard modeling commands set has been defined. Mapping relations between the standard modeling commands set and the native modeling commands set of commercial CAD systems are defined.

• 한국CDE학회논문집
• /
• 제7권1호
• /
• pp.1-8
• /
• 2002

A Hotchkiss spring has been widely utilized for commercial vehicle. Usually, the Hotchkiss spring has non-linear characteristics, i.e. it has a piecewise spring stiffness as well as hysterisis phenomenon. Therefore, the modeling of the Hotchkiss spring requires many considerations to fulfill satisfactory vehicle kinematic and dynamic relationships. Also, the spring has difficulties in modeling for presenting contact mechanism. In this paper, the modeling technique for the Hotchkiss spring has been descried. The modeling covers non-linear characteristics as well as contact problems for multi-body dynamic simulation. The force-displacement results are compared with experimental and FEM ones. Also, the comparison between three link type leaf spring model and proposed one has been considered in this paper.

• 전기학회논문지
• /
• 제61권12호
• /
• pp.1959-1963
• /
• 2012

Since electric railway load is variable largely due to starting and braking characteristics as well as various operation patterns, load modeling is not easy but complicated. For this reason, a simple technique for modeling of electric railway load of is required to analyze the AC substation system of electric railway. In this paper, a modeling technique of converter-based electric railway load is proposed and is tested using nonlinear loads on Matlab/Simulink.

• 대한전기학회논문지:전력기술부문A
• /
• 제52권3호
• /
• pp.179-182
• /
• 2003

Component-based method for load model not only should include the performances of the load components, but also should take into consideration the core losses of transformers, the line losses and the capacitor banks. Especially, capacitor bank affects the accuracy of reactive load model in load modeling. But it is difficult to identify actual reactive powers of capacitor banks in power system for load modeling. This research improves the component-based modeling method including uncertain capacitor bank. The proposed method is hybrid technique, which adds the measurement-based method to the existing component-based method for reliable information of capacitor band. The results of case studies were presented to verify the validity of the proposed method.