• 대한기계학회논문집
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• 제16권7호
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• pp.1351-1362
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• 1992

본 연구에서는 단순한 구간대신에 구간내에 제한된 형태의 가능성 분포를 갖 는 복합구간으로 학장하는 것이다. 그리고 이러한 가능성 분포는 퍼지 집합이론에서 사용되는 것처럼 일반적인 분포형태 전체를 사용하는 것이 아니라, 가능성 분포의 무 게중심만 정의하고 이 무게중심과 구간경계만을 사용하여 시스템 변수가 갖는 정성값 을 나타낸다. 이를 바탕으로 새로운 상태변화와 그 규칙을 정의함으로써 정성 모델 링과 시뮬레이션을 할 수 있는 정성 수학을 공식화하였다.이와 같은 방식으로 구한 정성 모델과 추론방법으로 기존의 논문에 나와 있는 시뮬레이션 결과와 비교하여 본 논문에서 제시한 정성해의 논리적 건전성(soundness)을 보였다.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2001년도 추계학술대회 학술발표 논문집
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• pp.65-68
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• 2001

Short shot is a molded part that is incomplete since insufficient material was injected into the mold. Remedial actions to solve short shot can be done by injection molding experts based on their empirical knowledge. Modifying mold and part, changing resin to less viscous one, and adjusting process conditions are general remedies. Experts of injection molding might try to adjust process conditions such as mold temperature, melt temperature, injection time based on their empirical knowledge as the first remedy because adjustment of process conditions is the most economic way in time and cost. However it is difficult to find appropriate process conditions as they are highly coupled and there are so many elements to be considered. In this paper, a fuzzy logic algorithm has been proposed to find an appropriate mold temperature. With the percentage of the insufficient Quantity of an injection molded part, an appropriate mold temperature can be obtained by the fuzzy logic algorithm.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.1228-1230
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• 1992

The permanent magnet synchronous motor(PMSM) is receiving Increased attention for servo drive applications in recent years because of its high torque to inertia ratio, superior power density and high efficiency. By vector-controll method, PMSM has the same operating characterics as seperately excited dc motor. The drive system of servo motor is requested to have an accurate response for the reference input and a quick recovery for the disturbance such as load torque. However, when the unknown disturbances and parameter variations are imposed on the permanent magnet synchronous motor(PMSM), the drive system is significantly effected by them. As a result, the drive system with both a fast compensation and a robustness to a parameter variations is requested. This paper investigates the possibility of applying the fuzzy logic controller(FLC) using Multi-Rule Base In a servo motor control system. In this paper, The five Rule Bases(1 to 5) are selected to recover the state error caused by the disturbance in steady state. In the initial operating mode. Rule Base 0 is used. To show the validity of the proposed fuzzy logic controll system, the computer simulation results are provided.

• 한국안전학회지
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• 제31권4호
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• pp.120-125
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• 2016

Usually, a risk can be expressed as a product of likelihood and consequence of a hazard factor. Therefore, conventional risk assessment is carried out by frequency analysis and severity analysis, in turns. However, it is well known that intuitive thinking is another excellent way of thinking of human beings. This study aimed to confirm whether there exist any difference in risk assessment results derived by two different procedures - intuitive and analytical. Thus, the present study showed 10 different illustrations to 30 undergraduate students. Their responses were organized as fuzzy membership functions, and summarized as risk assessments, and compared. The results were also verified with the help of statistical hypothesis testing, which showed no significant difference. On the contrary, however, similarity measure used in fuzzy set theory was not credible as anticipated. Many cases failed to satisfy statistical hypothesis even with similarity measure higher than 0.60 so that only a trend could be accepted. In addition, a subject showed a somewhat consistent logical discrepancy in his response, which implied the necessity of sincere analysis in fuzzy formulations.

• 한국정보통신학회논문지
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• 제5권3호
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• pp.605-611
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• 2001

고수준의 정보 서비스를 제공하기 위해서는 소프트웨어의 고품질화를 추구하여야 한다. 기존에 개발된 품질측정방법들은 모듈내에 포함되어 있는 요인항목들을 서로 다른 관점에서 개별적으로 측정하고있어 통합적인 평가방법이 필요하다. 따라서 본 논문에서는 다수의 측정 방법들을 모두수용 할 수 있는 모델을 제안한다. 제안된 모델은 비율척도들을 선택하고, 러프논리를 이용하여 그들의 중요도를 산출한다. 다음으로 모듈의 품질도를 측정하기 위해서 퍼지적분을 이용하여 척도들의 중요도와 측정값을 종합한다. 마지막으로 척도들과 산출된 품질도의 상관관계를 분석하고, 통계적 방법으로 제안된 모델의 타당성을 보인다.

• 제어로봇시스템학회논문지
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• 제13권4호
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• pp.352-357
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• 2007

This paper deals with modeling method and application of Fuzzy Discrete Event System(FDES). FDES have characteristics which Crisp Discrete Event System(CDES) can't deals with and is constituted with the events that is determined by vague and uncertain judgement like biomedical or traffic control. We proposed Real-time Fuzzy Temporal Logic Framework(RFTLF) to model Fuzzy Discrete Event System. It combines Temporal Logic Framework with Fuzzy Theory. We represented the model of traffic signal systems for intersection to have the property of Fuzzy Discrete Event System with Real-time Fuzzy Temporal Logic Framework and designed a traffic signal controller for smooth traffic flow. Moreover, we proposed the method to find the minimum-time route to reach the desired destination with information obtained in each intersection. In order to evaluate the performance of Real-time Fuzzy Temporal Logic Framework model proposed in this paper, we simulated unit-time extension traffic signal controller model of the latest signal control method on the same condition.

• 한국정밀공학회지
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• 제19권12호
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• pp.70-77
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• 2002

Necessity of the tole-operation has been increased in many fields. Since the Internet is inexpensive and available all over the world, it is a strong candidate for the transmission media of the tole-operation. However, the Internet has random time delays that may cause instability in the system especially if the tole -operation is bilateral. In the past few years many attempts have been made to overcome the random time delay, So far, they are still insufficient in terms of performance. The ‘Variable holding time’ is introduced to improve the performance of the ‘Event based tole-operation’ which controls a system with a non-time action reference. By holding each event for proper time, the system can quickly respond and be stabilized. The proper holding time should be selected based on the characteristics of the task that the system performs. The factors that reflect those characteristics are investigated. The fuzzy logic is employed to obtain the proper holding time for each event while the tole-operation system is in operation. The experimental results presented in this paper verify effectiveness of the proposed method.

• 한국지능시스템학회논문지
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• 제14권3호
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• pp.304-309
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• 2004

본 논문에서는 편리한 방식으로 착용할 수 있으며 지능을 지니고 있는 시스템을 구현하고자 한다. 인간을 보조하는 역할을 수행함과 동시에 착용할 수 있는 장점을 지닌 시스템의 구현은 다양한 제어기에 적용될 수 있다. 이동 중인 로봇의 상태를 파악하고 인간을 대신하여 명령을 전달해주는 시스템의 구현이 가능해진 것이다. 본 논문에서는 이동 로봇의 주행 정보를 받아들여 충돌 회피 주행에 필요한 속도와 회전각을 판단하여 명령을 전달하는 시스템을 착용 형태의 장치를 이용하여 구현하였다. 웨어러블 장치의 지능을 구현하기 위해 계층적 퍼지 논리와 신경망의 학습 능력을 결합하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 F
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• pp.2764-2766
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• 1999

The information of the motor speed and flux are more necessary than the other informations which have to get for the induction motor drive. which is the exact informations of the speed and flux are known without the speed and flux sensors, many problems for induction motor drive will be solved. In this paper, it is studied on the method able to get the informations of the speed and the flux for the induction motor. The informations for the rotator speed and flux of the induction motor are estimated exactly and rapidly by the observer system proposed in this paper and the induction motor is controlled by those informations of the speed and flux exactly and rapidly by the fuzzy controller set in the observer system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 A
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• pp.225-230
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• 1992

In this paper, a new learning fuzzy logic controller(LFLC) is presented. The proposed controller is composed of the main control part and the learning part. The main control part is a fuzzy logic controller(FLC) based on linguistic rules and fuzzy inference. For the learning part, artificial neural network(ANN) is added to FLC so that the controller may adapt to unknown plant and environment. According to the output values of the ANN part, which is learned using error back-propagation algorithm, scale factors of the FLC part are determined. These scale factors transfer the range of values of input variables into corresponding universe of discourse in the FLC part in order to achieve good performance. The effectiveness of the proposed control strategy has been demonstrated through simulations involving the control of an unknown robot manipulator with load disturbance.