• 제목/요약/키워드: Fuzzy Sets

검색결과 784건 처리시간 0.029초

지방정부 간 자율적 행정구역 통합의 성공요인 탐색: 퍼지집합 질적비교분석(fsQCA)의 적용

  • 양고운;박형준
    • 한국지방자치학회보
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    • 제25권1호
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    • pp.91-116
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    • 2013
  • The purpose of this paper is to find out the set of the factors influencing on the successful voluntary consolidation among local governments. This paper considers the voluntary consolidation as a kind of coordination mechanism and institutional collective action process between local governments, and identifies the configurations of the causal factors influencing the voluntary consolidations by applying the fuzzy-set analysis. It is found that the sets of the causal factors which include political and economic homogeneity factors in the region, and interlocal political, economic, and social homogeneity factors, and prior consolidation experience between regions have positive effects on the consolidations. Also, it turns out that interlocal homogeneity and conformity between regions should be considered significantly for institutionalization which supports the consolidation between local entities.

다목적 유전자 알고리즘을 이용한 퍼지제어기의 설계 (Design of Fuzzy Controller using Multi-objective Genetic Algorithm)

  • 김현수;;이동근
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 2005년도 춘계 학술발표회 논문집
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    • pp.209-216
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    • 2005
  • The controller that can control the smart base isolation system consisting of M damper and friction pendulum systems(FPS) is developed in this study. A fuzzy logic controller (FLC) is used to modulate the M damper force because the FLC has an inherent robustness and ability to handle non-linearities and uncertainties. A genetic algorithm (GA) is used for optimization of the FLC. When earthquake excitations are applied to the structures equipped with smart base isolation system, the relative displacement at the isolation level as well as the acceleration of the structure should be regulated under appropriate level. Thus, NSGA-II(Non-dominated Sorting Genetic Algorithm) is employed in this study as a multi-objective genetic algorithm to meet more than two control objectives, simultaneously. NSGA-II is used to determine appropriate fuzzy control rules as well to adjust parameters of the membership functions. Effectiveness of the proposed method for optimal design of the FLC is judged based on computed responses to several historical earthquakes. It has been shown that the proposed method can efficiently find Pareto optimal sets that can reduce both structural acceleration and base drift from numerical studies.

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Predicting the compressive strength of self-compacting concrete containing fly ash using a hybrid artificial intelligence method

  • Golafshani, Emadaldin M.;Pazouki, Gholamreza
    • Computers and Concrete
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    • 제22권4호
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    • pp.419-437
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    • 2018
  • The compressive strength of self-compacting concrete (SCC) containing fly ash (FA) is highly related to its constituents. The principal purpose of this paper is to investigate the efficiency of hybrid fuzzy radial basis function neural network with biogeography-based optimization (FRBFNN-BBO) for predicting the compressive strength of SCC containing FA based on its mix design i.e., cement, fly ash, water, fine aggregate, coarse aggregate, superplasticizer, and age. In this regard, biogeography-based optimization (BBO) is applied for the optimal design of fuzzy radial basis function neural network (FRBFNN) and the proposed model, implemented in a MATLAB environment, is constructed, trained and tested using 338 available sets of data obtained from 24 different published literature sources. Moreover, the artificial neural network and three types of radial basis function neural network models are applied to compare the efficiency of the proposed model. The statistical analysis results strongly showed that the proposed FRBFNN-BBO model has good performance in desirable accuracy for predicting the compressive strength of SCC with fly ash.

퍼지 연관규칙을 이용한 뉴스레터 시스템 설계 및 구현 (Design AND IMPLEMENTATION of A News letter system using fuzzy association rules)

  • 정연홍;박우수;박규석
    • 인터넷정보학회논문지
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    • 제3권5호
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    • pp.41-49
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    • 2002
  • 웹 마이닝은 World Wide Web으로부터 유용한 정보를 발견하고 분석하는 일로 정의 할 수 있다. 본 논문에서는 이러한 웹 마이닝을 통하여, 사용자 접근 페이지(성향)를 분석하고, 사용자에게 유용한 정보를 제공할 수 있는 시스템을 구축 하였다. 제안 시스템은 웹 사이트를 방문한 사용자의 행동과 발송된 뉴스레터로부터의 행동에 따른 정보를 조사하고 필터링을 통해 카테고리별로 분류과정을 거친다. 이러한 과정을 통해 생성된 각 카테고리에 대해 최근에 접근한 사용자들에 퍼지 연관규칙 (fuzzy association rules)을 적용하며, 이렇게 생성된 집합과 각 사용자가 접근한 페이지들의 집합을 비교하여 각 사용자에게 적합한 뉴스레터를 발송할 수 있다.

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비선형 시스템의 적응 퍼지 슬라이딩 모드 제어 (Adaptive Fuzzy Sliding-Mode Control of Nonlinear System)

  • 김도우;양해원;조민호
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2000년도 추계학술대회 논문집 학회본부 D
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    • pp.689-693
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    • 2000
  • In this paper, we proposed a decoupled adaptive fuzzy sliding-mode control scheme in designing the SMC of a class of fourth-order nonlinear systems. These systems are decoupled the whole system into two second-order systems such that each subsystem has a separate control target expressed in terms of a sliding surface. Then, information from the secondary target conditions the main target, which, in turn, generates a control action to make both subsystem move toward their sliding surface. respectively, and Two sets of fuzzy rule bases are utilized to represent the equivalent control input with unknown system functions of the main target, The membership functions of the THEN-part. which is used to construct a suitable equivalent control of SMC. are changed according to adaptive law, Under this design scheme, we not only maintain the distribution of membership functions over state space but also reduce considerably computing time, we apply the decoupled adaptive sliding-mode control to control a nonlinear inverted pendulum system and confirms the validity of the proposed approach.

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부하불평형 및 부하모형을 고려한 복합배전계통의 분산형전원의 연계 방안 (Interconnection of Dispersed Generation Systems considering Load Unbalance and Load Model in Composite Distribution Systems)

  • 이유정;김규호;이상근;유석구
    • 대한전기학회논문지:전력기술부문A
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    • 제53권5호
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    • pp.266-274
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    • 2004
  • This paper presents a scheme for the interconnection of dispersed generator systems(DGs) based on load .unbalance and load model in composite distribution systems. Groups of each individual load model consist of residential, industrial, commercial, official and agricultural load. The unbalance is involved with many single-phase line segment. . Voltage profile improvement and system loss minimization by installation of DGs depend greatly on how they are placed and operated in the distribution systems. So, DGs can reduce distribution real power losses and replace large-scale generators if they are placed appropriately in the distribution systems. The main idea of solving fuzzy goal programming is to transform the original objective function and constraints into the equivalent multi-objectives functions with fuzzy sets to evaluate their imprecise nature for the criterion of power loss minimization, the number or total capacity of DGs and the bus voltage deviation, and then solve the problem using genetic algorithm. The method proposed is applied to IEEE 13 bus and 34 bus test systems to demonstrate its effectiveness.

쓰레기 소각장 입지선정에 있어서 퍼지집합과 AHP 이론의 활용 (The Site Selection of Waste Incinerator Using Fuzzy Sets and AHP Theory)

  • 이희연;임은선
    • Spatial Information Research
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    • 제7권2호
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    • pp.223-236
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    • 1999
  • 본 연구는 최근 시설의 확충이 절실히 요구됨에서 불구하고 사회적 기피시설로 인식되어 그 입지를 둘러싸고 많은 사회적 문제를 일으키고 있는 쓰레기 소각장의 후보입지를 선정하는데 있어서 보다 유연성있고 객관적인 방법론을 도입하여 의사결정을 위한 지원시스템으로의 GIS 기능을 높이려는데 목적을 두었다. 본 연구에서는 종전의 입지분석시에 주로 많이 활동된 부울 논리에 의한 단순 도면중첩기능의 문제점을 제시하고 쓰레기 소각장의 입지를 선정하는데 있어서 퍼지집합(Fuzzy Set) 과 계층분석과정(AHP : Anlaystic Hierarchy Process) 이론을 활용하여 후보 입지들에 대한 적합도 수준을 평가하는데 보다 유연성을 l할수 있는 방법론을 모색하였다. 특히 본 연구는 쓰레기 소각장의 후보입지들을 선정하는데 있어서 어떠한 요인을 기회요인으로 하였는가, 또한 각 요인들에 대한 상대적 중요성, 즉 가중치를 어떻게 설정하였는가에 따라서 다양한 결과들이 추출될 수 있음을 제시하려는데 초점을 두었다.

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퍼지 로직을 이용한 해상에서의 다중 선박 또는 장애물 충돌 위험도 분석 (Risk Analysis for Collision of Multiple Vessels or Obstacles using Fuzzy Logic in Maritime)

  • 이한울;조홍래;박장식;김현태;유윤식
    • 한국정보통신학회:학술대회논문집
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    • 한국해양정보통신학회 2011년도 추계학술대회
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    • pp.487-488
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    • 2011
  • 해상 물동량의 증가와 해양레저의 활성화로 국내 연안의 해양사고 위험은 더욱 증가하고 있다. 본 논문은 해상에서 이동하는 소형 선박을 기준으로 근접하는 여러 선박 또는 장애물에 대한 퍼지 로직을 이용한 충돌 위험도를 분석하는 방법을 제시하였다. 퍼지 집합으로는 탑승한 배의 속도, 반경 1km 이내 장애물 개수, 진행방향 좌우 $15^{\circ}$ 이내의 장애물 개수를 고려 대상으로 하였다.

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Bayesian Nonlinear Blind Channel Equalizer based on Gaussian Weighted MFCM

  • Han, Soo-Whan;Park, Sung-Dae;Lee, Jong-Keuk
    • 한국멀티미디어학회논문지
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    • 제11권12호
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    • pp.1625-1634
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    • 2008
  • In this study, a modified Fuzzy C-Means algorithm with Gaussian weights (MFCM_GW) is presented for the problem of nonlinear blind channel equalization. The proposed algorithm searches for the optimal channel output states of a nonlinear channel based on received symbols. In contrast to conventional Euclidean distance in Fuzzy C-Means (FCM), the use of the Bayesian likelihood fitness function and the Gaussian weighted partition matrix is exploited in this method. In the search procedure, all possible sets of desired channel states are constructed by considering the combinations of estimated channel output states. The set of desired states characterized by the maxima] value of the Bayesian fitness is selected and updated by using the Gaussian weights. After this procedure, the Bayesian equalizer with the final desired states is implemented to reconstruct transmitted symbols. The performance of the proposed method is compared with those of a simplex genetic algorithm (GA), a hybrid genetic algorithm (GA merged with simulated annealing (SA):GASA), and a previously developed version of MFCM. In particular, a relative]y high accuracy and a fast search speed have been observed.

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Effects of Uncertain Spatial Data Representation on Multi-source Data Fusion: A Case Study for Landslide Hazard Mapping

  • Park No-Wook;Chi Kwang-Hoon;Kwon Byung-Doo
    • 대한원격탐사학회지
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    • 제21권5호
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    • pp.393-404
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    • 2005
  • As multi-source spatial data fusion mainly deal with various types of spatial data which are specific representations of real world with unequal reliability and incomplete knowledge, proper data representation and uncertainty analysis become more important. In relation to this problem, this paper presents and applies an advanced data representation methodology for different types of spatial data such as categorical and continuous data. To account for the uncertainties of both categorical data and continuous data, fuzzy boundary representation and smoothed kernel density estimation within a fuzzy logic framework are adopted, respectively. To investigate the effects of those data representation on final fusion results, a case study for landslide hazard mapping was carried out on multi-source spatial data sets from Jangheung, Korea. The case study results obtained from the proposed schemes were compared with the results obtained by traditional crisp boundary representation and categorized continuous data representation methods. From the case study results, the proposed scheme showed improved prediction rates than traditional methods and different representation setting resulted in the variation of prediction rates.