• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1993년도 Fifth International Fuzzy Systems Association World Congress 93
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• pp.1155-1158
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• 1993

Proficiency in creating a knowledge base is required for high accuracy fuzzy control. To overcome this a fuzzy inference method is proposed that take these membership functions from the probability densities showing the distribution of the mesurement values. And a method using a rough fuzzy knowledge base automatically created from the basic measurement data and tuned using the gradient method is proposed. In actual tests, these were applied to automatic high accuracy adjustment devices for magnetic head and for high frequency circuits with good results.

• Journal of Information Processing Systems
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• 제7권4호
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• pp.595-612
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• 2011

Most organizations use performance appraisal system to evaluate the effectiveness and efficiency of their employees. In evaluating staff performance, performance appraisal usually involves awarding numerical values or linguistic labels to employees performance. These values and labels are used to represent each staff achievement by reasoning incorporated in the arithmetical or statistical methods. However, the staff performance appraisal may involve judgments which are based on imprecise data especially when a person (the superior) tries to interpret another person's (his/her subordinate) performance. Thus, the scores awarded by the appraiser are only approximations. From fuzzy logic perspective, the performance of the appraisee involves the measurement of his/her ability, competence and skills, which are actually fuzzy concepts that can be captured in fuzzy terms. Accordingly, fuzzy approach can be used to handle these imprecision and uncertainty information. Therefore, the performance appraisal system can be examined using Fuzzy Logic Approach, which is carried out in the study. The study utilized a Cascaded fuzzy inference system to generate the performance qualities of some University non-teaching staff that are based on specific performance appraisal criteria.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 심포지엄 논문집 정보 및 제어부문
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• pp.24-26
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• 2005

At present, KS-1000 which is one of a commercial measurement instrument for motor fault diagnosis has been used in industrial field. The measurement system of KS-1000 is composed of three part : harmonic acquisition, signal processing by KS-1000 algorithm, diagnosis for motor fault. First of all, voltage signal taken from harmonic sensor is analysed for frequency by KS-1000 algorithm. Then, based on the result values of analysis skilled expert makes a judgment about whether motor system is the abnormality or degradation state. But the expert system such a motor fault diagnosis is very difficult to bring the expectable results by mathematical modeling due to the complexity of judgment process. In this reason, we propose an automation system using fuzzy model based on genetic algorithm(GA) that builded a qualitative model of a system without priori knowledge about a system provided numerical input output data.

• 한국정밀공학회지
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• 제15권10호
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• pp.180-192
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• 1998

This paper introduces a new self-organizing fuzzy logic controller (SOFLC) for precision contour machining in the presence of large disturbances which adjusts both input and output membership functions simultaneously. The parameters of the proposed controller are self-tuned in real-time according to a continuous measurement of the performance of the controller itself and estimated disturbance values. The proposed controller as well as a conventional fuzzy logic controller and a PID controller were simulated and implemented on a 3-axis milling machine in contour milling. Both the simulations and experiments show that the self-organizing fuzzy logic controller has superior performance in terms of contour tracking accuracy compared with the other two controllers.

• Journal of Advanced Marine Engineering and Technology
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• 제22권3호
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• pp.311-319
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• 1998

DC Motors have been widely used in industry as driving power motors for electrical vehicles cranes and winches due to their strong starting torques and as servo-motors for position and speed control systems due to their convenience of speed control etc. Generally in the speed control systems of motors speed sensors are required and this fact results in he increased price and operating cost and in the limitted applications. This paper presents a new speed control method for sensorless DC motors. In this scheme the speed signal is estimatd by the measurement values of the armature voltage and current. A Fuzzy feedback controller instead of the conventional PID controller. Through simulations the effectiveness and usefullness of the proposed method are illustrated.

• 한국항만경제학회지
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• 제26권2호
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• pp.82-98
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• 2010

본 연구에서는 첫째, 퍼지DEA모형을 해운항만분야에 이용한 국내외 기존연구들을 간략하게 검토하였으며, 둘째, Campos and Gonzalez(1989), 임성묵(2008)의 평균지수변환모형을 이론적으로 소개하였으며, 셋째, 국내 26개항만을 대상으로 2개의 투입요소(접안능력, 하역능력), 2개의 산출요소(화물처리량, 입출항척수)를 이용하여 평균지수변환모형에 의거하여 효율성을 분석하고 해석하였다. 실증분석결과를 요약해 보면 다음과 같다. 첫째, 일반 투입지향 CCR모형에서는 통영, 고현, 옥포, 속초항이 효율적이었으며, 여수항이 90% 후반의 효율성을 보였다. 둘째, 퍼지DEA 평균지수변환모형에서는 고현, 속초항이 가장 효율적이었으며, 옥포, 여수항은 람다값이 커질수록 효율성이 증가되었다. 또한 완도, 여수, 서귀포항은 람다값이 높아질 수록 효율성수치도 높아졌다. 셋째, 일반적인 투입지향 CCR 모형의 효율성 수치와 평균지수변환법에 의한 효율성수치의 평균순위는 거의 일치하였다. 본 논문이 갖는 정책적인 함의는 국내항만의 정책입안담당자들은 투입요소와 산출요소의 값을 정확히 알지 못하고 애매모호한 수준에서 알고 있을 때, 본 논문에서 사용한 퍼지 DEA 평균지수모형을 이용할 필요성이 있다는 점이다.

• 인지과학
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• 제6권2호
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• pp.27-45
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• 1995

본 논문에서는 다중 분류기의 통합을 위해 퍼지 행위지식 공간을 구성하고 이를 이용하는 방법을 제안한다.기존의 행위지식 공간은 각 분류기들이 서로 독립적일 필요가 없고 적응적 학습이 가능한 것으로 단지 하나의 클래스 레이블만 을 출력하는 분류기들의 통합에 가장 최적의 방법으로 알려졌다.그러나 행위지식 공간은 각 분류기가 출력하는 클래스 레이블에 대한 측정값과 경험적 지식을 통합과정에 반영하기 어렵다는 문제점을 갖고 있다.이러한 행위지식 공간의 문제점을 해결하기 위해 본 논문에서는 퍼지개념을 이용한 퍼지 행위지식 공간을 정의하고 이를 다중 분류기의 통합에 적용하기 위한 방법을 기술한다.또한,퍼지 행위지식 공간의 유용성을 증명하기 위해 각 분류기로 부터 얻어진 클래스 레이블들과 이에 관련된 측정값을 포함하는 분류결과들의 통합에 적용된 실험결과를 기술한다.

• 디지털융복합연구
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• 제14권7호
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• pp.363-371
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• 2016

벤처기업의 기술혁신을 위한 기술력 평가는 급변하는 기업환경, 평가시 사용하는 언어의 모호성과 애매성, 평가지표의 부정확성을 고려해야 한다. 본 논문에서는 벤처기업의 대표적인 정성적 평가요인인 흡수역량 및 기술적 기업가정신을 대상으로 다기준 의사결정법인 Fuzzy-AHP를 적용하여 요인의 중요도와 우선순위 및 동적역량을 산출하는 ACTEM(Absorption Capacity and Technology Entrepreneurship Monitor) 모델을 제안하였다. 평가척도가 되는 요인에 대한 가중치 산출은 퍼지이론을 도입하여 인지적 판단의 애매성을 보완하고, 기존의 기술력 평가 측정에 관한 연구에서 고려하지 않은 흡수역량과 기술적 기업가정신 및 동적역량에 대한 평가 기준들을 제시함으로써, 현실적인 대안을 선택하는 것이 가능하도록 하였다. ACTEM 모델을 기존의 AHP 평가방법과 비교한 결과, 흡수역량에서는 '지식획득', 기술적 기업가 정신에서는 '제품화 능력'이 가장 높게 나오는 등의 타당성을 검증할 수 있었다.

• 제어로봇시스템학회논문지
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• 제15권2호
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• pp.139-147
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• 2009

When the visually impaired walks inside a building like corridor, a GPS cannot be useful for the walker in estimating his or her position unlike the case of outdoor space. This paper presents two novel methods to measure the walking distance using a low cost camera worn on the chest of the visually impaired. In the first method we analyze the periodic variation of image focusing values. Walking steps are counted by checking the period for the rough measure of the walking distance. The second method counts the step number by monitoring fixtures on the ceiling, which have a certain interval. Lamps on the ceiling appeared on the video are monitored in this paper. The T-S fuzzy theory is used to detect lamps, and the walking steps are estimated by the positional variation of the lamp due to the gait of the walker. The two methods are tested in real experiment, and the results are compared.

• 산업경영시스템학회지
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• 제20권43호
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• pp.321-331
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• 1997

Measurement of attributes is often highly subjective and imprecise, yet most MADM methods lack provisions for handling imprecise data. Frequently, decision makers must establish a ranking within a finite set of alternatives with respect to multiple attributes which have varying degrees of importance. The problem is more complex if the evaluations of alternatives according to each attribute are not expressed in precise numbers, but rather in fuzzy numbers. Analysis must allow for lack of precision and partial truth. The advantages of a fuzzy approach for MADM are that a decision maker can obtain efficient solutions all at once without trial and error, and that this approach provides better support for judging the interactive improvement of solutions in comparison with o decision making method. The algorithm used in this study is based on the concepts of vague set theory. Linguistic variables and vague values are used to facilitate a decision maker's subjective assessment about attribute weightings and the appropriateness of alternative versus selection attributes in order to obtain final scores which are called vague appropriateness indices. A numerical example is presented to show the practical applicability of this approach.