• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2008.04a
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• pp.311-312
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• 2008

Fuzzy logic is introduced by Zadeh in 1965. It has been continuously developed by many mathematicians and knowledge engineers all over the world. A lot of papers concerning with the history of mathematics and the mathematical education related with fuzzy logic, but there is no paper concerning with Zadeh. In this article, we investigate his life and papers about fuzzy logic. We also compare two-valued logic, three-valued logic, fuzzy logic, intuisionistic logic and intuitionistic fuzzy sets. Finally we discuss about the expression of intuitionistic fuzzy sets.

• Journal of the Korean Operations Research and Management Science Society
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• v.30 no.1
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• pp.75-94
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• 2005

Research in the decision sciences has continued to develop a variety of mathematical models as well as software tools supporting corporate decision-making. Yet. in spite of their potential usefulness, the models are little used in real-world decision making since the model solution processes are too complex for ordinary users to get accustomed. This paper proposes an intelligent and flexible model-solver integration framework that enables the user to solve decision problems using multiple models and solvers without having precise knowledge of the model-solution processes. Specifically, for intuitive model-solution, the framework enables a decision support system to suggest the compatible solvers of a model autonomously without direct user intervention and to solve the model by matching the model and solver parameters intelligently without any serious conflicts. Thus, the framework would improve the productivity of institutional model solving tasks by relieving the user from the burden of leaning model and solver semantics requiring considerable time and efforts.

• Journal of Engineering Education Research
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• v.23 no.1
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• pp.37-46
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• 2020

The purpose of this study is to develop the self-reported measurement for engineering design competency. In this study, engineering design competency is defined as the overall individual ability that is necessary for an engineer for his/her successful accomplishment of engineering design. This measurement was developed through reviewing documents, defining factor and sub-factor, making an item and constructing validity verification. The self-reported measurement for engineering design competency consists of 6 factors and 40 items. 6 factors cover competency of design performance, competency of considering economic and social influence, competency of utilizing mathematical and scientific knowledge, competency of teamwork, competency of design-centered thinking and competency of collecting and using data. A 6-points Likert scale was used for each item.

• Journal for History of Mathematics
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• v.25 no.2
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• pp.57-70
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• 2012

In this study, a teaching unit for mathematically gifted students is designed, based on Lakatos's perspective. First, students appreciated the exceptions of Desargue theorem and introduced the point at infinity to remove the exceptions. Finally students were guided to realize that the exceptions and the general case of Desargue theorem have equal status. Exploring Desargue theorem with other viewpoints, gifted students experienced the growth of mathematical knowledge due to exceptions of the theorem.

• Transactions of the Korean Society of Automotive Engineers
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• v.2 no.5
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• pp.23-29
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• 1994

The design procedure for fuzzy logic controller depends on the expert's knowledge or trial and error. Moreover, it is very difficult to guarantee the stability and robustness of the system due to the linguistic expression of fuzzy control. However, fuzzy logic control has succeeded in many control problems that the conventional control theory has difficulties to deal with. As a result, this control theory is applied to the engine control system which a mathematical model is difficult. In this study, the fuzzy logic is applied to obtain the gain of PI control at idle speed control system, and a simple engine model is developed in order to perform simulation. Experimental results show that the response to reach the target engine speed at idle speed control system is improved by adopting the gain obtained with fuzzy logic.

• Proceedings of the KIEE Conference
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• 1998.07b
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• pp.681-683
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• 1998

Fuzzy Inference System is to trans late and be concrete with human expert in to mathematical equation. It is easy to be applied for Nonlinear System and the know ledge can be applied at that. With using the rule according to the Knowledge, when it is realized simulations must be required repeatedly and small vibration is generated in steady state, too. In this paper, we applied the system to the methodology of optimization with self-learn ing by us ing ANFIS(Adaptive Network-based Fuzzy Inference System) which makes use of back-propagation and least square method at a first order Sugeno Fuzzy System. In order to show the effect of Algorithm, we demonstrated it by us ing Rotary Inverted Pendulum.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1996.10a
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• pp.123-128
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• 1996

In this paper, a fuzzy controller is proposed for the operation of stoker-type refuse incinerator with many kinds of uncertain factors. To build the exact mathematical model is very difficult because of the variation of physical/chemical properties of refuse as a fuel and the complexity of the combusiton process. The fuzzy controller consists of fuzzy sensor, fuzzy decision maker and tracking part. The rules based on the professional operators empirical knowledge are made for the control of the boiler evaporation rate, emission gas and refuse throughput. For the performance measure of the proposed fuzzy controller, the model of the incinerator is constructed and the simulation results are given.

• Journal of the Korean Institute of Intelligent Systems
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• v.11 no.8
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• pp.736-741
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• 2001

The restoration optimum image from transformation image demands compound change of image change, calender reform, and multiple solution calculation. This study presents that system actively deal with outside interference, vibration, movement, mechanical feature on the operating or before the operating and avoids complicated mathematical numerical expression and revise based on expert knowledge based which applies Fuzzy Logic which is one of Artificial Intelligent technique.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.11
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• pp.1885-1891
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• 2007

This paper presents a distance relaying algorithm for phase-to-ground faults in transmission lines under Multi-Agent protection environment. In normal condition, a distance relay agent stores the latest states, e.g., voltage of source side, voltage of the opposite side and the loading conditions, etc., through communication between the agents. Once a fault occurs, the relay calculates the fault location using the knowledge about the states just before the fault happens. This stand-alone operation is to improve reliability under the fault condition at which the accuracy or time required for communication may not be guaranteed. The mathematical expression of fault location is derived through loop analysis, before hand, in the manner that both fault current from the opposite end and fault resistance are included implicitly so that their effects are minimized. The suggested algorithm is applied to a typical transmission system with two power sources on both ends to show its effectiveness.

• Journal of Communications and Networks
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• v.12 no.3
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• pp.253-265
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• 2010

The problem of pricing for a telecommunication network is investigated with respect to the users' sensitivity to the pricing structure. A functional optimization problem is formulated, in order to compute price reallocations as functions of data collected in real time during the network evolution. No a-priori knowledge about the users' utility functions and the traffic demands is required, since adaptive reactions to the network conditions are sought in real time. To this aim, a neural approximation technique is studied to exploit an optimal pricing control law, able to counteract traffic changes with a small on-line computational effort. Owing to the generality of the mathematical framework under investigation, our control methodology can be generalized for other decision variables and cost functionals.