• 제목/요약/키워드: Linguistic variables

검색결과 122건 처리시간 0.023초

퍼지결함수분석을 이용한 교량시스템의 상태 및 안전성 평가 (The Condition and Safety Assessment using Fuzzy Fault Tree Analysis for Bridge System)

  • 이중빈;나기현;손용우;박주원
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 1999년도 가을 학술발표회 논문집
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    • pp.79-86
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    • 1999
  • This paper aims to propose a method that helps maintenance engineers to evaluate the damage states of bridge systems by using a Fuzzy Fault Tree Analysis(FFTA). It may be stated that Fuzzy Fault Tree Analysis may be may useful for the systematic md rational condition and safety assessment for real bridge systems problems because the approach is able to effectively deal with all the related bridge system damages in terms of the linguistic variables that incorporate systematically experts experiences and subjective judgement.

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퍼지제어기의 자기동조 방법에 관한 연구 (Self-Tuning Method for Fuzzy Controller)

  • 최한수;김성중
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1993년도 하계학술대회 논문집 A
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    • pp.218-220
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    • 1993
  • This paper deals with a self-tuning fuzzy controller. The fuzzy controller is constructed with linguistic rules which consist of the fuzzy variables and fuzzy sets. Each of fuzzy sets is characterized by a membership function. The tuning fussy controller has paramemters to effect control output. In this paper we propose tuning method for the scaling factor. Computer simulations carried out on a second-order process will show how the present tuning approach improves the transient and steady-state characteristics of the overall system.

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비상대응모델의 불확실한 변수에 대한 퍼지이론의 적용 (Application of the Fuzzy Set Theory to Uncertain Parameters in a Countermeasure Model)

  • 한문희;김병우
    • Journal of Radiation Protection and Research
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    • 제19권2호
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    • pp.109-120
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    • 1994
  • 원자력시설의 비상사태 시 주변주민을 보호하기 위한 비상대응행위의 효과를 평가할 필요가 있다. 비상대응행위는 지역특성과 개인 행동특성에 따라 매우 다양하게 나타날 수 있으므로, 비상대응행위를 나타내는 변수들은 특정 값을 갖기보다는 일정구간에 분포되는 값을 갖는다. 대부분의 기존 비상대응모델에서는 계산을 단순화시키기 위하여 가정을 통해 특정 값을 사용한다. 단순화 과정중에 필연적으로 정보의 손실이 발생되어 결과적으로 비상대응 모델은 큰 불확실성을 포함하게 된다. 피지이론은 변수의 불확실성을 계산에 포함시켜 엄밀한 계산을 통해 정보손실을 최소화시키면서 계산결과를 얻어낼 수 있는 수학적인 도구를 제공해 준다. 본 연구에서는 퍼지집합, 퍼지추론, 퍼지관계 등의 이론을 응용하여 원자력시설의 비상사태 시 비상대응효과를 평가할 수 있는 방법을 개발하였다. 개발된 모델의 장점은 언어변수를 이용하여 지역특성을 표현하고 전문가의 의견을 반영하여 비상대응효과를 평가하므로, 단순화 가정중에 유발되는 정보의 손실을 줄일 수 있는데 있다. 비상대응 모델내의 불확실한 변수에 대한 퍼지이론의 응용성을 개선하기 위해서는 전문가의 의견을 반영하여 변수들에 대한 적합한 멤버쉽 함수와 퍼지조건문을 확립할 필요가 있다.

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스카라형 이중 아암 로봇의 실시간 퍼지제어기 실현 (Implementation of Real-Time Fuzzy Controller for SCARA Type Dual-Arm Robot)

  • 김홍래;한성현
    • 제어로봇시스템학회논문지
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    • 제10권12호
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    • pp.1223-1232
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    • 2004
  • We present a new technique to the design and real-time implementation of fuzzy control system basedon digital signal processors in order to improve the precision and robustness for system of industrial robot in this paper. The need to meet demanding control requirement in increasingly complex dynamical control systems under significant uncertainties, leads toward design of intelligent manipulation robots. The TMS320C80 is used in implementing real time fuzzy control to provide an enhanced motion control for robot manipulators. In this paper, a Self-Organizing Fuzzy Controller for the industrial robot manipulator with a actuator located at the base is studied. A fuzzy logic composed of linguistic conditional statements is employed by defining the relations of input-output variables of the controller. In the synthesis of a Fuzzy Logic Controller, one of the most difficult problems is the determination of linguistic control rules from the human operators. To overcome this difficult Self-Organizing Fuzzy Controller is proposed for a hierarchical control structure consisting of basic and high levels that modify control rules. The proposed Self-Organizing Fuzzy Controller scheme is simple in structure, fast in computation, and suitable for implementation of real-time control. Performance of the SOFC is illustrated by simulation and experimental results for a Dual-Arm robot with eight joints.

Utilizing Prosodic Information on the Sentence Comprehension in Children with High Functioning Autism

  • Chung, Chan-Hee;Lee, Hee-Ran;Kim, Jin-Dong
    • 대한의생명과학회지
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    • 제23권4호
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    • pp.362-371
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    • 2017
  • The purpose of this study is to investigate difficulties in using prosodic information to identify the meaning of ambiguous sentences in children with high functioning autism (HFA). Fifteen high functioning autistic children and fifteen children who matched their chronological age (CA) participated in this study. We compared the performance of the two groups by conducting syntactically and affectively ambiguous sentence comprehension (SASC and AASC) tasks. The results of this study show that in both tasks, the difference between the two groups was statistically significant at each condition and the performance of high functioning autistic children was significantly lower. In a correlation analysis of major variables, children who matched CA showed a correlation between prosody-only (PO) and AASC, while children with HFA showed a correlation between PO and MO (morpheme-only). Children with HFA used grammatical morpheme information to understand general sentences. We found that the ability to use prosodic information in children with HFA is significantly lower than that of normally developed children. Considering the relevance of prosody to linguistic, non-linguistic and emotional aspects of communication, improving prosodic perception is thought to be a way to mediate deficits in the comprehension of ambiguous sentences in children with HFA.

쾌속조형공정 선정을 위한 지원 시스템 (A Decision Support System for the Selection of a Rapid Prototyping Process)

  • 변홍석;이관행
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2003년도 춘계학술대회 논문집
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    • pp.5-8
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    • 2003
  • This paper presents a methodology to be able to select an appropriate RP system that suits the end use of a part. Evaluation factors used in process selection include major attributes such as accuracy, roughness, strength, elongation, part cost and build time that greatly affect the performance of RP systems. Crisp values such as accuracy and surface roughness are obtained with a new test part developed. The test part is designed with conjoint analysis to reflect users' preference. The part cost and build time that have approximate ranges due to cost and many variable parameters are presented by linguistic values that can be described with triangular fuzzy numbers. Based on the evaluation values obtained, an appropriate RP process for a specific part application is selected by using the modified TOPSIS(Technique of Order Preference by Similarity to Ideal Solution) method. It uses crisp data as well as linguistic variables, and each weight on the alternatives is assigned by using pair-wise comparison matrix. The ranking order helps the decision making of the selection of RP systems.

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결함수분석법과 퍼지논리를 이용한 FMECA 평가 (FMECA using Fault Tree Analysis (FTA) and Fuzzy Logic)

  • 김동진;신준석;김형준;김진오;김형철
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2007년도 추계학술대회 논문집
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    • pp.1529-1532
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    • 2007
  • Failure Mode, Effects, and Criticality Analysis (FMECA) is an extension of FMEA which includes a criticality analysis. The criticality analysis is used to chart the probability of failure modes against the severity of their consequences. The result highlights failure modes with relatively high probability and severity of consequences, allowing remedial effort to be directed where it will produce the greatest value. However, there are several limitations. Measuring severity of failure consequences is subjective and linguistic. Since The result of FMECA only gives qualitative and quantitative informations, it should be re-analysed to prioritize critical units. Fuzzy set theory has been introduced by Lotfi A. Zadeh (1965). It has extended the classical set theory dramatically. Based on fuzzy set theory, fuzzy logic has been developed employing human reasoning process. IF-THEN fuzzy rule based assessment approach can model the expert's decision logic appropriately. Fault tree analysis (FTA) is one of most common fault modeling techniques. It is widely used in many fields practically. In this paper, a simple fault tree analysis is proposed to measure the severity of components. Fuzzy rule based assessment method interprets linguistic variables for determination of critical unit priorities. An rail-way transforming system is analysed to describe the proposed method.

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DSPs(TMS320C80)을 이용한 8축 듀얼 아암 로봇의 실시간 퍼지제어 (Real-Time Fuzzy Control for Dual-Arm with 8 Joints Robot Using the DSPs(TMS320C80))

  • 한성현;김종수
    • 한국공작기계학회논문집
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    • 제13권1호
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    • pp.35-47
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    • 2004
  • In this paper presents a new approach to the design and real-time implementation of fuzzy control system based-on digital signal processors(DSP:IMS320C80) in order to improve the precision and robustness for system of industrial robot(Dual-Arm with 8 joint Robot). The need to meet demanding control requirement in increasingly complex dynamical control systems under significant uncertainties, leads toward design of intelligent manipulation robots. The IMS320C80 is used in implementing real time fuzzy control to provide an enhanced motion control for robot manipulators. In this paper, a Self-Organizing Fuzzy Controller(SOFC) for the industrial robot manipulator with a actuator located at the base is studied. A fuzzy logic composed of linguistic conditional statements is employed by defining the relations of input-output variables of the controller. In the synthesis of a FLC(Fuzzy Logic Controller), one of the most difficult problems is the determination of linguistic control rules from the human operators. To overcome this difficult SOFC is proposed for a hierarchical control structure consisting of basic and high levels that modify control rules. The proposed SOFC scheme is simple in structure, Int in computation, and suitable for implementation of real-time control. Performance of the SOFC is illustrated by simulation and experimental results for a Dual-Arm robot with eight joints.

On the Design of Simple-structured Adaptive Fuzzy Logic Controllers

  • Park, Byung-Jae;Kwak, Seong-Woo
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • 제3권1호
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    • pp.93-99
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    • 2003
  • One of the methods to simplify the design process for a fuzzy logic controller (FLC) is to reduce the number of variables representing the rule antecedent. This in turn decreases the number of control rules, membership functions, and scaling factors. For this purpose, we designed a single-input FLC that uses a sole fuzzy input variable. However, it is still deficient in the capability of adapting some varying operating conditions although it provides a simple method for the design of FLC's. We here design two simple-structured adaptive fuzzy logic controllers (SAFLC's) using the concept of the single-input FLC. Linguistic fuzzy control rules are directly incorporated into the controller by a fuzzy basis function. Thus some parameters of the membership functions characterizing the linguistic terms of the fuzzy control rules can be adjusted by an adaptive law. In our controllers, center values of fuzzy sets are directly adjusted by an adaptive law. Two SAFLC's are designed. One of them uses a Hurwitz error dynamics and the other a switching function of the sliding mode control (SMC). We also prove that 1) their closed-loop systems are globally stable in the sense that all signals involved are bounded and 2) their tracking errors converge to zero asymptotically. We perform computer simulations using a nonlinear plant.

Pragmatic Strategies of Self (Other) Presentation in Literary Texts: A Computational Approach

  • Khafaga, Ayman Farid
    • International Journal of Computer Science & Network Security
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    • 제22권2호
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    • pp.223-231
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    • 2022
  • The application of computer software into the linguistic analysis of texts proves useful to arrive at concise and authentic results from large data texts. Based on this assumption, this paper employs a Computer-Aided Text Analysis (CATA) and a Critical Discourse Analysis (CDA) to explore the manipulative strategies of positive/negative presentation in Orwell's Animal Farm. More specifically, the paper attempts to explore the extent to which CATA software represented by the three variables of Frequency Distribution Analysis (FDA), Content Analysis (CA), and Key Word in Context (KWIC) incorporate with CDA decipher the manipulative purposes beyond positive presentation of selfness and negative presentation of otherness in the selected corpus. The analysis covers some CDA strategies, including justification, false statistics, and competency, for positive self-presentation; and accusation, criticism, and the use of ambiguous words for negative other-presentation. With the application of CATA, some words will be analyzed by showing their frequency distribution analysis as well as their contextual environment in the selected text to expose the extent to which they are employed as strategies of positive/negative presentation in the text under investigation. Findings show that CATA software contributes significantly to the linguistic analysis of large data texts. The paper recommends the use and application of the different CATA software in the stylistic and corpus linguistics studies.