• Title/Summary/Keyword: fuzzy variable

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Improved Performance of Permanent Magnet Synchronous Motor by using Particle Swarm Optimization Techniques

  • Elwer, A.S.;Wahsh, S.A.
    • Journal of Power Electronics
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    • v.9 no.2
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    • pp.207-214
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    • 2009
  • This paper presents a modem approach for speed control of a PMSM using the Particle Swarm Optimization (PSO) algorithm to optimize the parameters of the PI-Controller. The overall system simulated under various operating conditions and an experimental setup is prepared. The use of PSO as an optimization algorithm makes the drive robust, with faster dynamic response, higher accuracy and insensitive to load variation. Comparison between different controllers is achieved, using a PI controller which is tuned by two methods, firstly manually and secondly using the PSO technique. The system is tested under variable operating conditions. Implementation of the experimental setup is done. The simulation results show good dynamic response with fast recovery time and good agreement with experimental controller.

The concept of σ-morphism as a probability measure on the set of effects (이펙트 집합에서 확률측도로서 시그마 모르피즘 개념)

  • Yun, Yong-Sik;Kang, Kyoung-Hun;Park, Jin-Won
    • Journal of the Korean Institute of Intelligent Systems
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    • v.19 no.3
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    • pp.371-374
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    • 2009
  • In this paper, we introduce the concepts of effects and observable as generalizations of event and random variable, respectively. Also, we introduce the concept of $\sigma$-morphism and we investigate some results on $\sigma$-morphism as a probability measure on the set of effects.

A study on Generalized Synchronization in the State-Controlled Cellular Neural Network(SC-CNN)

  • Rae Youngchul;Kim Yi-gon;Tinduka Mathias
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.5 no.4
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    • pp.291-296
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    • 2005
  • In this paper, we introduce a generalized synchronization method and secure communication in the State-Controlled Cellular Neural Network (SC-CNN). We make a SC-CNN using the n-double scroll. A SC-CNN is created by applying identical n-double scroll or non-identical n-double scroll and Chua's oscillator with weak coupled method to each cell. SC-CNN synchronization was achieved using GS(Generalized Synchronization) method between the transmitter and receiver about each state variable in the SC-CNN. In order to secure communication, we have synthesizing the desired information with a SC-CNN circuit by adding the information signal to the hyper-chaos signal using the SC-CNN in the transmitter. And then, transmitting the synthesized signal to the ideal channel, we confirm secure communication by separating the information signal and the SC-CNN signal in the receiver.

Camera Motion Parameter Estimation Technique using 2D Homography and LM Method based on Invariant Features

  • Cha, Jeong-Hee
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.5 no.4
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    • pp.297-301
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    • 2005
  • In this paper, we propose a method to estimate camera motion parameter based on invariant point features. Typically, feature information of image has drawbacks, it is variable to camera viewpoint, and therefore information quantity increases after time. The LM(Levenberg-Marquardt) method using nonlinear minimum square evaluation for camera extrinsic parameter estimation also has a weak point, which has different iteration number for approaching the minimal point according to the initial values and convergence time increases if the process run into a local minimum. In order to complement these shortfalls, we, first propose constructing feature models using invariant vector of geometry. Secondly, we propose a two-stage calculation method to improve accuracy and convergence by using homography and LM method. In the experiment, we compare and analyze the proposed method with existing method to demonstrate the superiority of the proposed algorithms.

A Study on Design Decision of Qualitative Design Factors in Selecting of HVAC Type for Building (건축물의 공조방식 선택과정에 있어서 질적 설계요소들의 디자인 결정방법에 관한 연구)

  • 우세진
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.16 no.8
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    • pp.762-769
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    • 2004
  • Not only in building design but also in HVAC system design, it is important to ensure an objectivity in schematic design. In the study, the author suggested a method to make a logical decision for quality design factors a(footing the selection of HVAC type in initial design process, and to provide objective design values. Fuzzy theory, one of the theories describing in quantitative way the ambiguous-natured linguistic values, was used to determine the qualitative design factors of linguistic parameter nature. It was found that it has a potential as a method to determine a HVAC type satisfying the required values of qualitative design factors involved in selection of the system type. But this needs further studies to be settled in the selecting of HVAC type.

Position Control of Brushless DC Motor using Single Input Fuzzy Variable Structure Controller (단일 입력 퍼지가변구조제어기에 의한 BLDC 모터의 위치제어)

  • 배준성;최병재;이대식
    • Journal of the Korean Institute of Intelligent Systems
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    • v.11 no.1
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    • pp.9-15
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    • 2001
  • 브러쉬 없는 직류전동기의 위치제어를 위한 퍼지가변구조제어기를 설계한다. 특히 본 논문에서는 기존의 퍼지제어 기법에서 얻을 수 있는 특징으로부터 하나의 전건부 변수만을 가지는 간단한 퍼지논리제어기의 설계를 기술한다. 가변구조제어는 시스템의 파라메터 변화나 외란에 둔감한 특성을 갖는다. 하지만 리칭페이스에서는 문제가 된다. 이를 개선하기 위하여 본 논문에서는 지수항을 추가한 비선형 슬라이딩면을 구성한다. 그리고 나서 비선형 슬라이딩 면과 슬라이딩 면의 변화율을 입력으로 하는 퍼지 제어기를 설계한다. 이러한 2-입력 퍼지가변구조제어기의 제어 규칙표로부터 하나의 전건부 변수만을 가지는 단일 입력 퍼지가변구조제어기를 설계한다. 이들 제어기의 성능을 입증하기 위하여 시뮬레이션과 실험을 수행한다.

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Design of Multi-FPNN Model Using Clustering and Genetic Algorithms and Its Application to Nonlinear Process Systems (HCM 클러스처링과 유전자 알고리즘을 이용한 다중 FPNN 모델 설계와 비선형 공정으로의 응용)

  • 박호성;오성권;안태천
    • Journal of the Korean Institute of Intelligent Systems
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    • v.10 no.4
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    • pp.343-350
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    • 2000
  • In this paper, we propose the Multi-FPNN(Fuzzy Polynomial Neural Networks) model based on FNN and PNN(Polyomial Neural Networks) for optimal system identifacation. Here FNN structure is designed using fuzzy input space divided by each separated input variable, and urilized both in order to get better output performace. Each node of PNN structure based on GMDH(Group Method of Data handing) method uses two types of high-order polynomials such as linearane and quadratic, and the input of that node uses three kinds of multi-variable inputs such as linear and quadratic, and the input of that node and Genetic Algorithms(GAs) to identify both the structure and the prepocessing of parameters of a Multi-FPNN model. Here, HCM clustering method, which is carried out for data preproessing of process system, is utilized to determine the structure method, which is carried out for data preprocessing of process system, is utilized to determance index with a weighting factor is used to according to the divisions of input-output space. A aggregate performance inddex with a wegihting factor is used to achieve a sound balance between approximation and generalization abilities of the model. According to the selection and adjustment of a weighting factor of this aggregate abjective function which it is acailable and effective to design to design and optimal Multi-FPNN model. The study is illustrated with the aid of two representative numerical examples and the aggregate performance index related to the approximation and generalization abilities of the model is evaluated and discussed.

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An Analysis on Global Terminal Operator's Selection of Container Terminal -Focusing on the Chinese Container Ports- (GTO의 신규터미널 후보지 선택에 관한 연구 -중국 컨테이너 항만을 중심으로-)

  • Yeo, Gi-Tae;Jung, Hyun-Jae;Pak, Ji-Young
    • Journal of Korea Port Economic Association
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    • v.28 no.1
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    • pp.159-178
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    • 2012
  • Recently, Global network expansion strategy of GTOs(Global Terminal Operator) coupled with each country's port policy, plays huge role for the evolution of modern container port. The Chinese ports can be regarded as the major markets to the GTOs. However, there are scant of researches for finding the key success factors of GTOs' strategies when they consider to invest in overseas. In this respect, the aims of this study were to draw out the evaluation variables for successful investment strategies of GTOs, and to calculate the selected target ports. The 14 variables are selected including the variable named 'development potentiality of a port' through literature reviews. Using the Factor Analysis (FA) based on selected variables, four principal factors were extracted such as 'ability for port operating and cargo generating', 'the trade route and volume', 'the calling potentiality for large vessels' and 'the possibility of utilization of existing infrastructure'. In addition, the weights of factors and variables are evaluated through Fuzzy AHP method. As a result, 'ability for port operating and cargo generating' is chosen as the most important factor among principal factors as scored 0.343, and 'the development potentiality of a port' (0.107) is represented as the most important variable among 14 detailed variables. In overall, from the Global Terminal Operator's point of view, Shanghai is ranked as most suitable port for operating new terminal among the top 5 Chinese ports.

Semi-Active Control of a Suspension System with a MR Damper of a Large-sized Bus (MR 댐퍼를 이용한 대형 버스 현가장치의 반능동 제어)

  • Yoon, Ho-Sang;Moon, Il-Dong;Kim, Jae-Won;Oh, Chae-Youn;Lee, Hyung-Won
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.21 no.4
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    • pp.683-690
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    • 2012
  • In this work, the semi-active control of a large-sized bus suspension system with an MR damper was studied. An MR damper model that can aptly describe the hysteretic characteristics of an MR damper was adopted. Parameter values of the MR damper model were suitably modified by considering the maximum damping force of a passive damper used in the suspension system of a real large-sized bus. In addition, a fuzzy logic controller was developed for semi-active control of a suspension system with an MR damper. The vertical acceleration at the attachment point of the MR damper and the relative velocity between sprung and unsprung masses were used as input variables, while voltage was used as the output variable. Straight-ahead driving simulations were performed on a road with a random road profile and on a flat road with a bump. In straight-ahead driving simulations, the vertical acceleration and pitch angle were measured to compare the riding performance of a suspension system with a passive damper with that of a suspension with an MR damper. In addition, a single lane change simulation was performed. In the simulation, the lateral acceleration and roll angle were measured in order to compare the handling performance of a suspension system using a passive damper with that of a suspension system using an MR damper.

Adaptive Multi-level Streaming Service using Fuzzy Similarity in Wireless Mobile Networks (무선 모바일 네트워크상에서 퍼지 유사도를 이용한 적응형 멀티-레벨 스트리밍 서비스)

  • Lee, Chong-Deuk
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.9
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    • pp.3502-3509
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    • 2010
  • Streaming service in the wireless mobile network environment has been a very challenging issue due to the dynamic uncertain nature of the channels. Overhead such as congestion, latency, and jitter lead to the problem of performance degradation of an adaptive multi-streaming service. This paper proposes a AMSS (Adaptive Multi-level Streaming Service) mechanism to reduce the performance degradation due to overhead such as variable network bandwidth, mobility and limited resources of the wireless mobile network. The proposed AMSS optimizes streaming services by: 1) use of fuzzy similarity metric, 2) minimization of packet loss due to buffer overflow and resource waste, and 3) minimization of packet loss due to congestion and delay. The simulation result shows that the proposed method has better performance in congestion control and packet loss ratio than the other existing methods of TCP-based method, UDP-based method and VBM-based method. The proposed method showed improvement of 10% in congestion control ratio and 8% in packet loss ratio compared with VBM-based method which is one of the best method.