• Journal of applied mathematics & informatics
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• 제33권5_6호
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• pp.607-625
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• 2015

Recently, Wang et al. [Computers and Mathematics with Ap-plications 57 (2009) 1232-1248.] and Wang and Watada [Information Sci-ences 179 (2009) 4057-4069.] studied the renewal process and renewal reward process with fuzzy random inter-arrival times and rewards under the T-independence associated with any continuous Archimedean t-norm. But, their main results do not cover the classical theory of the random elementary renewal theorem and random renewal reward theorem when fuzzy random variables degenerate to random variables, and some given assumptions relate to the membership function of the fuzzy variable and the Archimedean t-norm of the results are restrictive. This paper improves the results of Wang and Watada and Wang et al. from a mathematical per-spective. We release some assumptions of the results of Wang and Watada and Wang et al. and completely generalize the classical stochastic renewal theorem and renewal rewards theorem.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제9권1호
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• pp.1-3
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• 2009

Recently, Carlsson, Full\acute{e}$r and Majlender [1] presented the concept of possibilitic correlation representing an average degree of interaction between marginal distribution of a joint possibility distribution as compared to their respective dispersions. They also formulated the weak and strong forms of the possibilistic Cauchy-Schwarz inequality. In this paper, we define a new probability measure. Then the weak and strong forms of the Cauchy-Schwarz inequality are immediate consequence of probabilistic Cauchy-Schwarz inequality with respect to the new probability measure.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제9권2호
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• pp.99-104
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• 2009

The turn-to-turn short is one major fault of the motor faults of BLDC motors and can appear frequently. When the fault happens, the motor can be operated without breakdown, but it is necessary to maintain the motor for continuous working. In past research, several methods have been applied to detect winding faults. The representative approaches have been focusing on current signals, which can give important information to extract features and to detect faults. In this study, current sensors were installed to measure signals for fault detection of BLDC motors. In this study, the Park's vector method was used to extract the features and to isolate the faults from the current measured by sensors. Because this method can consider the three-phase current values, it is useful to detect features from one-phase and three-phase faults. After extracting two-dimensional features, the final feature was generated by using the two-dimensional values using the distance equation. The values were used in fuzzy similarity to isolate the faults. Fuzzy similarity is an available tool to diagnose the fault without model generation and the fault was converted to the percentage value that can be considered as possibility of the fault.

• 전기학회논문지
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• 제56권6호
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• pp.1007-1016
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• 2007

In power system, substation facilities have become too complex and larger according to an extended power system. Also, customers require the high quality of electrical power system. However, some facilities become old and often break down unexpectedly. The unexpected failure may cause a break in power system and loss of profits. Therefore it is important to prevent abrupt faults by monitoring the condition of power systems. Among the various power facilities, power transformers play an important role in the transmission and distribution systems. In this research, we develop intelligent diagnosis technique for predicting faults of power transformer by FCM(Fuzzy c-means) and Euclidean based distance measure. The proposed technique make it possible to measures the possibility and degree of aging as well as the faults occurred in transformer. To demonstrate the validity of proposed method, various experiments are performed and their results are presented.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1993년도 Fifth International Fuzzy Systems Association World Congress 93
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• pp.1254-1257
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• 1993

Presented in this paper is a newly developed motion planning method of an autonomous mobile robot(MAR) which can be applied to flexible manufacturing systems(FMS). The mobile robot is designed for transporting tools and workpieces between a set-up station and machines according to production schedules of the whole FMS. The proposed method is implemented based on an earlier developed real-time obstacle avoidance method which employs Kohonen network for pattern classification of sonar readings and fuzzy logic for local path planning. Particulary, a novel obstacle avoidance method for moving objects using a collision index, collision possibility measure, is described. Our method has been tested on the SNU mobile robot. The experimental results show that the robot successfully navigates to its target while avoiding moving objects.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2006년도 추계학술발표회
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• pp.253-258
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• 2006

본 연구는 우리나라 RCC/RSC의 효율성을 2개의 입력변수와 5개의 출력변수를 자료를 토대로 퍼지 DEA를 이용하여 측정 평가하였다. 특히, 본 연구에서는 해양사고 발생자료 뿐만 아니라 환경스트레스치에 의한 잠재적 해양사고 발생가능 자료도 고려하여 운영효율성을 분석하였다. 한편, 현실자료에는 수많은 애매성이 존재하기 때문에 본 연구에서는 DEA법에 퍼지이론을 이용한 퍼지 DEA 법을 이용하였다. 이 퍼지 DEA법은 ${\alpha}-cut$ 을 기반으로 한 크리습 선형계획문제로 변환된 것으로 입/출력 변수를 삼각형 퍼지수로 하여 해를 산출하는 방법을 제안하였고, 제안된 퍼지 DEA를 이용하여 퍼지 RCC/RSC의 순위를 결정하였다. ${\alpha}-cut$를 0.5 로 하여 효율성을 산출한 결과 YS, BS, MP, TS, JJ, PH, US, IC, SC, DH, GS, TA, WD RCC/RSC 순으로 효율성 이 높게 나타났다. 따라서 효율성이 비교적 낮게 평가된TA, WD RCC/RSC는 효율성이 높은 준거집단을 참조하여 벤치마킹을 해야할 필요가 있다.

• 해양환경안전학회지
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• 제13권3호
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• pp.207-212
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• 2007

본 연구는 우리나라 RCC/RSC의 효율성을 2개의 입력변수와 5개의 출력변수로 한 토대로 퍼지 DEA를 이용하여 측정 평가하였다. 특히, 본 연구에서는 해양사고 발생자료 뿐만 아니라 환경스트레스치에 의한 잠재적 해양사고 발생가능 자료도 고려하여 운영효율성을 분석하였다. 한편, 현실자료에는 수많은 애매성이 존재하기 때문에 본 연구에서는 DEA법에 퍼지이론을 이용한 퍼지 DEA법을 이용하였다. 이 퍼지DEA법은 ${\alpha}$-cut을 기반으로 한 크리습 선형계획문제로 변환된 것으로 입/출력 변수를 삼각형 퍼지수로 하여 해를 산출하는 방법을 제안하였고, 제안된 퍼지 DEA를 이용하여 퍼지 RCC/RSC의 순위를 결정하였다. ${\alpha}$-cut을 0.5로 하여 효율성을 산출한 결과 YS, BS, MP, TY, JJ, PH, US, IC, SC, DH, GS, TA, WD RCC/RSC 순으로 효율성이 높게 나타났다. 따라서 효율성이 비교적 낮게 평가된 TA, WD RCC/RSC는 효율성이 높은 준거집단을 참조하여 벤치마킹을 해야 할 필요가 있다.

• 한국전자통신학회논문지
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• 제5권5호
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• pp.487-492
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• 2010

본 연구에서는 분뇨수집운반차량의 분뇨수거량을 정확하게 계측하고, 계측된 결과를 이용하여 청소요금을 산출할 수 있는 시스템을 개발하였다. 탱크내부의 높이를 계측할 수 있는 수위센서 센서회로 그리고 분뇨수거 작업자가 편리하게 사용할 수 있도록 휴대형 중앙처리연산장치를 개발하였다. 청소요금을 수거현장에서 징수할 수 있도록 영수증 출력기능도 내장되었다. 또한 경사진 현장에서 작업을 진행하여도 각도센서를 이용하여 탱크 내부에 분뇨가 수거되는 량을 정확하게 측정할 수 있도록 하였다. 본 연구결과를 통하여 분뇨수거 시 발생되는 민원을 감소시킬 수 있으며, 특화된 시스템의 수출로 외화획득이 기대된다.