• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2002.05a
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• pp.127-130
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• 2002

본 논문은 수학적으로 모델링하기 어려운 비선형 시스템을 위한 새로운 계층적 규칙 기반 퍼지 시스템 모델링 기법을 제안한다. 제안된 기법은 퍼지 규칙 기반 구조를 상위 규칙 기반과 하위 규칙 기반으로 나누어 계층화 시키는 것이다 계층적 퍼지 규칙을 적용함으로써 퍼지 규칙을 효율적이고 논리적으로 이용할 수 있다. 퍼지 규칙의 효율적, 논리적 사용은 퍼지 시스템의 정확성을 높일 수 있고 구조를 명료화 시킬 수 있다. 유전 알고리즘은 제안된 퍼지 규칙의 파라미터 최적화 과정에 이용된다. 가스로 데이터에 대한 퍼지 모델링 결과를 통해서 제안된 기법의 타당성 및 효용성을 검증하고 타 기법의 결과와 비교한다.

• Proceedings of the KIPE Conference
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• 2019.11a
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• pp.164-165
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• 2019

본 논문은 3상 동기발전기의 과도 특성을 분석하기 위해 MATLAB/ SIMULINK를 이용하여 모델링하였으며 동기발전기 출력단의 개방 및 3상 단락 회로 조건에 따른 특성곡선을 분석하였다. 정상상태, 과도상태 및 차과도상태 구간에서 고정자 권선, 회전자 권선 및 댐퍼 권선 등이 갖는 자기 인덕턴스 및 상호 인덕턴스 특성 관계와 자속 변화특성 등을 수학적 모델 기반의 소신호 모델링을 통해 3상 동기발전기를 등가적으로 모델링하였다. 시뮬레이션을 통해 얻은 값에 의해 과도상태와 차과도상태의 모터 데이터를 분석하고 단락상태의 시간 상수를 계산하여, 동기발전기의 3상 단락 조건에서 초기 과도 및 과도상태의 특성을 검증하였다.최종적으로, 이론적 공식에 의해 계산 된 동기 발전기의 파라미터는 시뮬레이션 결과와 일치하며 오차는 2 % 범위 내에 있다.

• Journal of Engineering Education Research
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• v.10 no.2
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• pp.87-105
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• 2007

In this research, Integrated program base on heat transfer & numerical analysis was developed. Also, reaction of gifted student and possibility of application of this program was surveyed. This program consist in three parts. The first part is computer programing language, the second part is numerical modeling of physical phenomena, and the third part is numerical analysis. 4 students are selected who belong to mathematic class of CNUE(Cheoungju National Univ. of Edu.)'s Gifted Student Education Center. The Program consists in 15th lessens, and each lessen need 4hr. Application possibility and student's satisfaction of the program are studied through the interview and report of the student. Three of four students are accomplish the goal of the progarm. Computer programing and numerical analysis parts were relatively well understood, but numerical modeling part was difficult to students. The satisfaction of the program is dependent on the characteristics of the student. Most of the student thought that this program was one of the science education program. The student who have interested in only mathematics shows that low satisfaction but the one who have interested in science or information technology shows that high satisfaction.

• The KIPS Transactions:PartB
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• v.9B no.3
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• pp.277-286
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• 2002

Genetic programming (GP) has been combined with quantum mechanical perturbation theory to make a new algorithm to construct mathematical models and perform predictions for chaotic time series from real world. Procedural similarities between time series modeling and perturbation theory to solve quantum mechanical wave equations are discussed, and the exemplary GP approach for implementing them is proposed. The approach is based on multiple populations and uses orthogonal functions for GP function set. GP is applied to original time series to get the first mathematical model. Numerical values of the model are subtracted from the original time series data to form a residual time series which is again subject to GP modeling procedure. The process is repeated until predetermined terminating conditions are met. The algorithm has been successfully applied to construct highly effective mathematical models for many real world chaotic time series. Comparisons with other methodologies and topics for further study are also introduced.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.5323-5329
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• 2013

Many companies have tried to develop the horizontally vibrating linear motor, for sliming the smart phone. Mathematical modeling and analysis is one of method to simulate the dynamic performance of the horizonatally vibrating linear motor. However, the horizontally vibrating linear motor vibrates in twisting mode because there are two kinds of force acting on the vibrating part. One is are the horizontal force by Lorentz force. The other is the vertical force by attraction force between magnet of vibrating part and bracket and the gravity force of vibrating part. However, those are very difficult to be included in mathematical modeling which generate the simulation errors. In this paper, we perform MFBD (multi flexible body dynamics) simulation using commercial dynamic analysis program "DAFUL". In our new model, the force effects those are neglected in mathematical model, are included. For the verification, the simulation results are compared with the experiment results with manufactured prototype.

• Journal of Educational Research in Mathematics
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• v.18 no.1
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• pp.25-50
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• 2008

Several previous studies suggested that simulation could be a main didactic instrument in overcoming misconception and probability modeling. However, they have not described enough how to reorganize probability knowledge as knowledge to be taught in a curriculum using simulation. The purpose of this study is to identify the theoretical knowledge needed in developing a didactic transposition method of probability knowledge using simulation. The theoretical knowledge needed to develop this method was specified as follows : pseudo-contextualization/pseudo-personalization, and pseudo-decontextualization/pseudo-deper-sonalization according to the introductory purposes of simulation. As a result, this study developed a local instruction theory and an hypothetical learning trajectory for overcoming misconceptions and modeling situations respectively. This study summed up educational intention, which was designed to transform probability knowledge into didactic according to the introductory purposes of simulation, into curriculum, lesson plans, and experimental teaching materials to present didactic ideas for new probability education programs in the high school probability curriculum.

• Journal of the Korea Society for Simulation
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• v.25 no.1
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• pp.1-9
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• 2016

This study focuses on the air to air missile control fin planform optimization for the minimizing hinge moment with the considering phenomena of fluid and structure simultaneously. The fluid-structure interaction method is applied for the fluid and structure phenomena simulation of the control fins. A transient-loosely coupled method is used for the fluid-structure interaction simulation because it is suited for using each fluid and structure dedicated simulation software. Searching global optimization point is required many re-calculation therefore in this study, a mathematical model is applied for rapidly calculation. The face centered central composite method is used for generating design points and the 2nd polynomial response surface is sued for generating mathematical model. Global optimization is performed by using the generic algorithm. An objective function is the minimizing travel distance of the center of pressure between Mach 0.7 and 2.0 condition. Finally, the objective function of optimized planform is reduced 7.5% than the baseline planform with satisfying constrained conditions.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1360-1361
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• 2011

본 논문은 Synchronous Machine을 기반으로 하여 250[kVA]의 용량을 가지는 플라이휠을 모델링하고 그 예를 수학적으로 해석함으로써 분산전원으로서의 신재생에너지와 연계하여 에너지를 저장/출력할 수 있는 타당성을 검토할 수 있도록 한다.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.904-907
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• 2003

고층빌딩에서는 여러 대의 엘리베이터를 두어 이러한 이동의 요구를 만족시키게 된다. 여러 대의 엘리베이터를 둔 시스템에서는 한 대의 엘리베이터만 있는 시스템에서와 달리 여러 층에서의 이동요구를 효과적으로 여러 대의 엘리베이터에 분산해서 할당해 주는 기능이 필요하게 된다. 본 논문에서는 여러 대의 엘리베이터들을 보다 효과적으로 이용하여 승객의 대기 시간을 줄이기 위한 군 제어 방법의 연구를 위한 군 제어 시스템을 수학적으로 모델링 하였다.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 1998.11a
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• pp.261-266
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• 1998

손끝으로 물건을 문지르거나 잡아 질감을 느끼는 경우 나타나는 현상을 Hertzian 접촉이론을 응용하여 수학적인 모델링을 하였다. 물체표면에 손끝이 접촉하여 눌려지게되면 변형이 일어나게 되고 변형된 모양과 정도에 따라 촉감을 느끼게 .된다. 손끝은 점탄성체로서 누르는 변위에 따라 탄성계수와 점성계수 값이 비선형으로 변하게 되는 현상을 이론과 실험을 통하여 연구하였다. 특히 손끝이 직물을 누를 때 나타나는 현상을 측정하여 질감표현과의 관계를 분석하였다.