• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.327-332
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• 2003

A new discretization method for nonlinear system with time-delay is proposed. It is based on the well-known Taylor series expansion and the zero-order hold (ZOH) assumption. We know that a discretization of linear system can be obtained with the ZOH assumption and within the sampling interval. A similar line of thinking is available in nonlinear case. The mathematical structure of the new discretization method is explored and under the structure, the sampled-data representation of nonlinear system including time-delay is computed. Provided that the discrete form of the single input nonlinear system with time-delay is derived, this result is easily extended to nonlinear system with multi-input time-delay. For simplicity two inputs are considered in this study. It is enough to generalize that of multiple inputs. Finally, the time-discretization of non-affine nonlinear system with time-delay is investigated for apply all nonlinear system

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2000.11a
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• pp.448-451
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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, 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 because it is designed based on the input-output data and experimental knowledge obtained by trials.

• The Mathematical Education
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• v.48 no.4
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• pp.365-385
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• 2009

Recently, mathematical modeling has been attractive in that it could be one of many efforts to improve students' thinking and problem solving in mathematics education. Mathematical modeling is a non-linear process that involves elements of both a treated-as-real world and a mathematics world and also requires the application of mathematics to unstructured problem situations in real-life situation. This study provides analysis of literature review about modeling perspectives, case studies about mathematical modeling, and textbooks from the United States and Korea with perspective which mathematical modeling could be potential and meaningful to students even in elementary school. Further, teaching method with mathematical modeling was investigated to see the possibility of application to elementary mathematics classroom.

• Korean Institute of Interior Design Journal
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• v.20 no.3
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• pp.152-160
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• 2011

Contemporary architecture pursues new method of Interpretation of Non-linear space as digital media appears. As various materials and new methods can be used due to developments in science and expansion of thinking, contemporary architectural color developed extensive possibilities. It means not only the change of drawings, method of architectural product and materials but also the change of value system for architectural space. Thus the purpose of this paper is to suggest interpretation of space applied by color structure, and this point of view was based on the three elements of color perception which are light source, reflector, and observer. According to this categorization, architectural color of exterior color, layer color and interaction color are explained via examples of colors recently used on the contemporary architectures. In summary, contemporary architecture can be explained by Non-construction space interpretation for intrinsic complex meanings. Therefore, it can be explained as moving space, collage, by picturesque space, moving blur color and emptiness of color. This pursues various point of views for space interpretation, therefore it can be developed to the identity of strengthening architectures' design concept.

• Communications of Mathematical Education
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• v.18 no.2 s.19
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• pp.79-92
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• 2004

This paper offers an analysis of how students reasoned with the dynamic parameter time to support their mathematical activity and deepen their understandings of mathematical concepts. This mathematical thinking occurred as they participated in a differential equations class before, during, and instruction on solutions to linear systems of differential equations. Students participated in the following identified mathematical practices related to parametric reasoning during this time period: reasoning simultaneously in a qualitative and quantitative manner, reasoning by moving from discrete to continuous imaging of time, and reasoning by imagining the motion. Examples of this reasoning are provided in this report. Implications of this research include the possibility that instructional activities can build on this reasoning to help students learn about the mathematics of change at the middle school, high school, and the university.

• 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 Information Technology Applications and Management
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• v.20 no.4
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• pp.19-31
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• 2013

There is tremendous increasing demand on spectrum resource which is boosted by spread of cloud computing and M2M telecommunication as well as smart phone and tablet PC. Recently, spectrum sharing technology has drawn attention to the spectrum policy makers as a promising way to overcome limitation of scarce spectrum resource. To succeed in commercialization of spectrum sharing technology, it is necessary to prospect the future business ecosystem of spectrum sharing and develop appropriate policies and laws at the same time along with the advance of spectrum sharing technology. The purpose of this paper is to prospect future spectrum sharing ecosystem and analyze business ecosystem of spectrum sharing with casual loop map. With the causal map and system dynamics method, it is possible to analyze feedback loops which is not limited to linear thinking and build policies which optimize positive dynamics in business ecosystem of spectrum sharing.

• 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 Engineering Education Research
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• v.18 no.1
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• pp.61-73
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• 2015

The purpose of this study is to suggest some direction to support learning of students in college of engineering. It results from the assumption that engineering education accreditation should come with assessment of the educational process. To analyze the learning process, this study analyzed 5 categories - involvement in and out of instruction, faculty-student interaction, teaching-learning outcomes, and the system of student support. The Research method was questionnaire, and T-test and hierarchical linear model were used. The major findings are as follows. Major-level of satisfaction in teaching-learning and optional-level of satisfaction in teaching-learning are good. But the degree of self-directed learning activities and student-faculty interaction is low, and writing attitude and learning outcomes are not good. Student-faculty interaction, high-order thinking activities and active involvement have a good influence on learning outcomes. So this study suggests to enhance active involvement in instruction, high-order thinking activities, writing skills, and interaction with faculty for the improvement of quality of higher education.

• Journal of the Korean School Mathematics Society
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• v.11 no.3
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• pp.363-376
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• 2008

This study is to understand intuition that is the tool of invention and the one factor of the creative thinking in mathematical education. For this, I examine the nature of intuition and the history of research about intuition. And I study the result of research about intuition in cognitive psychological perspectives. This study brings to a focus in informational processing model. Informational processing model is similar to the mathematical problem solving process that is expressed linear process. Recently, parallel distributed processing models try to understand the nature of intuition. But any models cannot adequately explain the nature and the phenomena of illumination of intuition. Some scholars try to examine the intuition in mathematical education. But systematic and practical research is rare. So, I suggest the mathematical educational implications about intuition. Conclusively, it is necessary to systematic concern in intuition and the methods of improvement of intuition in mathematical education.