• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2283-2286
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• 2000

Sliding control is a powerful approach to controlling nonlinear and uncertain systems. Conventional sliding mode control suffer' from high control gain and chattering problem. also it needs mathematic! modeling equations for control systems. A Fuzzy controller is endowed with control rules and membership function that are constructed on the knowledge of expert, as like intuition and experience. but It is very difficult to obtain the exact values which are the membership function and consequent parameters. In this paper, without mathematical modeling equations, the plant parameters in sliding mode are estimated by the indirect adaptive fuzzy method. the proposed algorithm could analyze the system's stability and convergence behavior using Lyapunov theory. so sliding modes are reconstructed and decreased tracking error. moreover convergence time took a short. An example of inverted pendulum is given for demonstration of the robustness of proposed methodology.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2296-2298
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• 2000

Fuzzy control has been researched for application of industrial processes which have no accurate mathematical model and could not controlled by conventional methods because of a lack of quantitative input-output data. Intelligent control approach based on fuzzy logic could directly reflex human thinking and natural language to controller comparing with conventional methods. In this paper, fuzzy controller is implemented to acquire operator's knowledge. The tested system is constructed for sending a ball to the goal position using wind from two DC motors in the path. This system contains non-linearity and uncertainty because of the characteristic of aerodynamics inside the path. Ball position is measured by a vision camera. The system used in this experiment could be hardly modeled by mathematic methods and could not be easily controlled by linear control manners. The controller, in this paper is designed based on the input-output data and experimental knowledge obtained by trials.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.2
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• pp.32-37
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• 2011

This study developed Gear Automatic Design Program that users with the basic knowledge about mechanical engineering can easily model spur gears and helical gears. The Gear Automatic Design Program used Visual LISP which is an user program based on Auto CAD and made it model the gears with involute tooth by the exact mathematic definition. Also, to verify these, the reliability was secured by comparing it with a gear generated in commercial software. And we will develop nitrocarburising process and solve problems which had been caused of SCM440's dimensional changing.

• International Journal of Control, Automation, and Systems
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• v.6 no.1
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• pp.135-141
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• 2008

A new approach to $H_{\infty}$ multi-step prediction is developed by applying the innovation analysis theory. Although the predictor is derived by resorting to state augmentation, nevertheless, it is completely different from the previous works with state augmentation. The augmented state here is considered just as a theoretical mathematic tool for deriving the estimator. A distributed algorithm for the Riccati equation of the augmented system is presented. By using the reorganized innovation analysis, calculation of the estimator does not require any augmentation. A numerical example demonstrates the effect in reducing computing burden.

• Communications of Mathematical Education
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• v.9
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• pp.31-40
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• 1999

요즈음 수학 수업에서 협동 학습을 활용하여 문제 해결을 하는 경우가 많이 늘었다. 학생들이 소집단에서 함께 활동하면 더 나은 문제 해결자가 된다는 것을 알기 때문이다. 그러나 학생들에게 협동적인 상황에서 문제 해결을 하게 하면서 그 평가는 개인 평가나 전통적인 평가에 그치는 경우가 많다. 소집단 협동 학습은 소집단의 구성원이 협동을 할 때 그 효과가 큰 것이며, 소집단 협동 학습에서의 평가는 소집단에 있는 학생들이 수행한 것을 참되게(Authentic) 평가하여야 문제 해결에 대한 올바른 정보를 얻을 수 있고 각 학생들로 하여금 협동 학습에 적극적으로 참여하여 문제를 해결하게 할 수 있다. 만일 협동적인 문제 해결을 하였는데 개인 평가를 실시한다면 학생들은 집단에서 협동할 필요성을 적게 느끼게 되어, 학생들은 협동 학습에 적극적으로 참여하지 않으려 할 것이다. 1990년대 수학교육에 많은 영향을 끼치고 있는 NCTM의 Curriculum and Evaluation Standard for School Mathematics에서도 수학 지도 방법과 평가 방법이 일치하여야 한다고 강조하고 있다. 본고에서는 이와 같은 필요성에 의거하여 수학과 소집단 협동 학습의 유형을 알아보고, 협동적 문제 해결의 평가 방법을 알아보고자 한다.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2096-2098
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• 2001

Fuzzy control has been researched for application of industrial processes which have no accurate mathematical model and could not be controlled by conventional methods because of a lack of quantitative input-output data. Intelligent control approach based on fuzzy logic could directly reflex human thinking and natural language to controller comparing with conventional methods. In this paper, the tested system is constructed for sending a ball to the goal position using wind from two DC motors in the path. This system contains non-linearity and uncertainty because of the characteristic of aerodynamics inside the path. The system used in this experiment could be hardly modeled by mathematic methods and could not be easily controlled by linear control manners. The controller, in this paper could control the system containing non-linearity and uncertainty.

• Journal of Educational Research in Mathematics
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• v.12 no.4
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• pp.543-556
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• 2002

The purpose of this study is to find a method to improve geometry instruction. For this purpose, I have investigated aims and problems of geometry education. I also reviewed related literature about discovery methods as well as verification. Through this review, “Mathematising teaching and learning methods” by Freudenthal is Presented as an alternative to geometry instruction. I investigated the capability of dynamic software for realization of this method. The result of this investigation is that dynamic software is a powerful tool in realizing this method. At last, I present one example of mathematic activity using dynamic software that can be used by school teachers.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.1
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• pp.127-136
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• 2017

This paper investigates improved stability and stabilization criteria for sampled-data control systems. By using a suitable and newly constructed augmented Lyapunov-Krasovskii functional and some recent mathematic techniques such as auxiliary function-based integral inequalities, sufficient conditions for stability and stabilization conditions are derived within the framework of linear matrix inequalities(LMI) form. The superiority and validity of the proposed results are illustrated by three numerical examples.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.968-970
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• 2003

Fuzzy Controller is a system that displays a person's thoughts using membership function and IF-THEN rules. With the help of specialists' knowledge, rule bases can be explained in easy language. Furthermore Fuzzy Controller has strong resistance against turbulence. Its performance is especially prominent when targets cannot be measured in mathematic methods because the fuzzy controller can measure the output using only the relations between the input and output. But Fuzzy System has a problem that is calculation speed. I suggest you a theory to solve it. I applied a theory to inverted pendulum. Because it is represent of nonlinear system.

• Journal for History of Mathematics
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• v.18 no.4
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• pp.39-48
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• 2005

Many researchers consider Mesopotamian mathematics as the earliest form of mathematics. The aim of this article is to provide a brief overview of the environmental and social background which made mathematical development. Historically. mathematics is always a product of society. So it is valuable to study historical background which have produced mathematics.