• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2002년도 추계학술대회 및 정기총회
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• pp.317-320
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• 2002

In this paper, an automatic histogram specification method is proposed for image enhancement, Fuzzy membership value is adopted for the representation of image histogram. The desired PDF is automatically constructed by the fuzzy membership value. Fuzzy membership value is extracted from dark membership, bright membership function and original histogram. The effectual results are demonstrated by desired PDF which meet the image enhancement requirements. The performance and effectiveness are shown by the analysis and the resultant image in comparison with histogram equalization method.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 학술대회지
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• pp.842-845
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• 2004

The aim of this study is to compare the classification results for choosing the fuzzy membership function within fuzzy rules. There are various methods of extracting rules from training data in the process of fuzzy rules generation. Pattern distribution characteristics are considered to produce fuzzy rules. The accuracy of classification results are depended on not only considering the characteristics of fuzzy subspaces but also choosing the fuzzy membership functions. This paper shows how to produce various type of fuzzy rules from the partitioning the pattern spaces and results of land cover classification in satellite remote sensing images by adopting various fuzzy membership functions. The experiments of this study is applied to Landsat TM image and the results of classification are compared by fuzzy membership functions.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2002년도 춘계학술대회 및 임시총회
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• pp.145-148
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• 2002

Type-1 fuzzy value is used to show the uncertainty in a given value. But there exist many situations that it needs to be extended to type-2 fuzzy value because it is difficult to determine the crisp membership function itself. Intrinsically type-2 fuzzy values are more expressive and powerful than type-1 fuzzy values, but, at the same time, more difficult to be compared or ranked . In this paper, a ranking method for type-2 fuzzy values is proposed. It is based on the satisfaction function which shows the possibility that one type-2 fuzzy value is greater than the other type-2 fuzzy value Some properties of the proposed method are also analyzed .

• Journal of Advanced Marine Engineering and Technology
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• 제28권5호
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• pp.793-800
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• 2004

The purpose of this study is to develope a servo system with faster and more accurate response. This paper describes a method of approximate reasoning for fuzzy control of servo system based on the decomposition of $\alpha$-level fuzzy sets. We propose that fuzzy logic algorithm is a body from fuzzy inference to defuzzificaion cases where the output variable u directly is generated PWM The effectiveness for robust and faster response of the fuzzy control scheme are verified for a variable parameter by comparison with a PID control and fuzzy control A position control of DC servo system with a fuzzy logic controller is demonstrated successfully.

• 전자공학회논문지B
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• 제31B권6호
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• pp.43-52
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• 1994

A design method of rule-based fuzzy modeling is presented for the model identification of complex and nonlinear systems. The proposed rule-based fuzzy modeling implements system structure and parameter identification in the efficient form of ``IF....,THEN...', using the theories of optimization theory , linguistic fuzzy implication rules and fuzzy c-means clustering. Three kinds of method for fuzzy modeling presented in this paper include simplified inference (type I), linear inference (type 2), and modified linear inference (type 3). In order to identify premise structure and parameter of fuzzy implication rules, fuzzy c- means clustering and modified complex method are used respectively and the least sequare method is utilized for the identification of optimum consequence parameters. Time series data for gas furance and those for sewage treatment process are used to evaluate the performance of the proposed rule-based fuzzy modeling. Comparison shows that the proposed method can produce the fuzzy model with higher accuracy than previous other studies.

• 전기학회논문지P
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• 제51권4호
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• pp.163-168
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• 2002

This paper presents the comparison results of control algorithm for the simultaneous control of a multi output converter system that controls, simultaneously and independently, the separate Buck converter and Boost converter with the different specification by one DSP digital controller. As two separate converters are regulated by only one DSP, it is possible to achieve the simple digital control circuit for regulating the multi output DC-DC converter. By setting the software switch state, PI and Fuzzy controller can be applied as a controller for each converter without any change of hardware. Also, it is included the control characteristics comparison between PI and Fuzzy controller. The control characteristics of each PWM DC-DC converter is validated by experimental results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 추계학술대회 논문집 학회본부
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• pp.341-344
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• 1991

Current controlled pulse width modulation(PWM) for voltage source inverter(VSI) is one of the control method which controls the current directly so that we can perform vector control because it reduces the orders of differential equations of the induction machine. This paper propose a Fuzzy current controlled PWM which properly minimize a current ripple using Fuzzy theory in a constant switching frequency. This technique is applied to an electrical drive system with an induction machine(IM) by simulation. By comparison with the known classical method such as ramp comparison, hysteresis band method, our contribution shows the better performances.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 1998년도 가을 학술발표논문집 Vol.25 No.2 (2)
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• pp.30-32
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• 1998

퍼지숫자는 불명확한 값을 표현하기 때문에, 퍼지숫자의 비교결과 역시 불명확한 성질을 갖고 있다. 본 논문에서는 이러한 퍼지숫자의 비교결과에 존재하는 불명확성을 표현하기 위해서, 퍼지 만족도 함수를 제안한다. 퍼지 만족도 함수는 두 퍼지숫자를 비교하여 그 비교결과로 0과1사이의 퍼지집합을 출력한다. 즉, 어느 숫자가 다른 숫자보다 클(작을) 가능성을 단순히 0과1사이의 값이 아닌, 퍼지집합으로 표현한다. 퍼지 만족도 함수는 이전에 제안된 만족도 함수로부터 확장되었다. 본 논문에서는 만족도 함수를 간략히 소개하고, 이를 이용하여 퍼지 만족도 함수를 제안하며, 이를 퍼지숫자 비교에 적용한 예를 제시한다.

• 한국지능시스템학회논문지
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• 제13권6호
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• pp.722-728
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• 2003

In this paper, we propose a fuzzy traffic controller of Sugeno`s fuzzy model so as to model the nonlinear characteristics of controlling the traffic light. It use a degree of the traffic congestion of the preceding roads as an input so that it can cope with traffic congestion appropriately, which causes the loss of fuel and our discomfort. First, in order to construct fuzzy traffic controller of Sugeno`s fuzzy model, we model the control process of the traffic light by using Mamdani`s fuzzy model, which has the uniform membership functions of the same size and shape. Second, we make Mamdani`s fuzzy model with the non-uniform membership functions so that it can exactly reflect the knowledge of experts and operators. Last, we construct the fuzzy traffic controller of Sugeno`s fuzzy model by learning from the input/output data, which is retrieved from Mamdani`s fuzzy model with the non-uniform membership functions. We compared and analyzed the fixed traffic light controller, the fuzzy traffic controller of Mamdani`s fuzzy model and the fuzzy traffic controller of Sugeno`s fuzzy model by using the delay time and the proportion of the entered vehicles to the occurred vehicles. As a result of comparison, the fuzzy traffic controller of Sugeno`s fuzzy model showed the best performance.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1998년도 The Third Asian Fuzzy Systems Symposium
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• pp.573-578
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• 1998

In this paper, we propose a new technique of codification. The purpose of this method is to take in consideration the natural language nuances and the fuzziness that characterizes the human reasoning. So, we warranted a means of more flexible encoding that translates as well the linguistic descriptions. Its principle is simple and intuitive. It consists simply in replacing in ambiguous cases, a unique number by an interval. The introduction of the new codification necessitates the elaboration of metric or similarity in order to compare two intervals. This comparison must take in consideration the difference of their size, the remoteness of their center and the width of their intersection. In consequence, we defined three new fuzzy concepts : "fuzzy inclusion degree", "fuzzy resemblance degree," and " fuzzy curve".