• 제목/요약/키워드: a fuzzy theory

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문서 입출력 시스템의 구성에 관한 연구 (A Study on the Construction of a Document Input/Output system)

  • 함영국;도상윤;정홍규;김우성;박래홍;이창범;김상중
    • 전자공학회논문지B
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    • 제29B권10호
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    • pp.100-112
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    • 1992
  • In this paper, an integrated document input/output system is developed which constructs the graphic document from a text file, converts the document into encoded facsimile data, and also recognizes printed/handwritten alphanumerics and Korean characters in a facsimile or graphic document. For an output system, we develop the method which generates bit-map patterns from the document consisting of the KSC5601 and ASCII codes. The binary graphic image, if necessary, is encoded by the G3 coding scheme for facsimile transmission. For a user friendly input system for documents consisting of alphanumerics and Korean characters obtained from a facsimile or scanner, we propose a document recognition algirithm utilizing several special features(partial projection, cross point, and distance features) and the membership function of the fuzzy set theory. In summary, we develop an integrated document input/output system and its performance is demonstrated via computer simulation.

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Biosign Recognition based on the Soft Computing Techniques with application to a Rehab -type Robot

  • Lee, Ju-Jang
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2001년도 ICCAS
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    • pp.29.2-29
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    • 2001
  • For the design of human-centered systems in which a human and machine such as a robot form a human-in system, human-friendly interaction/interface is essential. Human-friendly interaction is possible when the system is capable of recognizing human biosigns such as5 EMG Signal, hand gesture and facial expressions so the some humanintention and/or emotion can be inferred and is used as a proper feedback signal. In the talk, we report our experiences of applying the Soft computing techniques including Fuzzy, ANN, GA and rho rough set theory for efficiently recognizing various biosigns and for effective inference. More specifically, we first observe characteristics of various forms of biosigns and propose a new way of extracting feature set for such signals. Then we show a standardized procedure of getting an inferred intention or emotion from the signals. Finally, we present examples of application for our model of rehabilitation robot named.

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격자형 지질정보의 자료유도 통합을 위한 이론적 배경 (Theoretical Background for Data-driven Integration of Raster-based Geological Information)

  • 이기원;지광훈
    • 대한공간정보학회지
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    • 제3권1호
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    • pp.115-121
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    • 1995
  • 최근 지리정보시스템의 여러 지질학적 응용 중에서 광물탐사를 위한 격자형 자료의 공간적 통합론에 관한 연구가 많이 이루어지고 있다. 본 연구에서는 보통 확률, 통계적 배경을 갖는 목표유도형방법과 구분되는 자료유도형 방법의 예로서 Dempster-Shafer의 이론과 퍼지이론의 이론적 배경을 자료재표현의 원리와 자료통합논리에 입각하여 설명하고자 한다. 기존의 지질, 지화학 및 물리탐사정보를 이용한 시해 연구에서 위의 두 이론은 광물탐사문제에 상당히 유용한 결정보조 정보를 제공하는 것으로 입증되고 있으며, 본 연구에서 논의된 몇 가지 관련 사항들은 이 이론들의 보다 적절한 실제 적용 및 해석에 도움이 될 것으로 생각된다.

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퍼지규칙을 이용한 교통사고분석 (Traffic Accident Analysis using Fuzzy Rules)

  • 박광채;배철수
    • 한국정보전자통신기술학회논문지
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    • 제8권1호
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    • pp.23-27
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    • 2015
  • 요즈음 교통사고를 줄이기 위하여 IT 기술을 이용한 교통사고 연구가 많이 진행되고 있다. 그러나, 뺑소니 교통사고 발생하면 가해차량을 현장에서 찾기가 매우 어렵다. 교통사고 조사 과학화를 위해서, RFID 기술 및 유비쿼터스 이론을 이용하여 효율적인 교통사고 예방 시스템을 구축하는 알고리즘을 제안하였다. 특별히, 본 논문에서는 시시각각 변화하는 따른 도로상황 및 날씨 조건에 변화에 따른 최적 교통안전 속도를 산출하는 모의실험을 하였다.

Path Following Control of Mobile Robot Using Lyapunov Techniques and PID Cntroller

  • Jin, Tae-Seok;Tack, Han-Ho
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • 제11권1호
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    • pp.49-53
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    • 2011
  • Path following of the mobile robot is one research hot for the mobile robot navigation. For the control system of the wheeled mobile robot(WMR) being in nonhonolomic system and the complex relations among the control parameters, it is difficult to solve the problem based on traditional mathematics model. In this paper, we presents a simple and effective way of implementing an adaptive following controller based on the PID for mobile robot path following. The method uses a non-linear model of mobile robot kinematics and thus allows an accurate prediction of the future trajectories. The proposed controller has a parallel structure that consists of PID controller with a fixed gain. The control law is constructed on the basis of Lyapunov stability theory. Computer simulation for a differentially driven nonholonomic mobile robot is carried out in the velocity and orientation tracking control of the nonholonomic WMR. The simulation results of wheel type mobile robot platform are given to show the effectiveness of the proposed algorithm.

Approximate Dynamic Programming-Based Dynamic Portfolio Optimization for Constrained Index Tracking

  • Park, Jooyoung;Yang, Dongsu;Park, Kyungwook
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • 제13권1호
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    • pp.19-30
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    • 2013
  • Recently, the constrained index tracking problem, in which the task of trading a set of stocks is performed so as to closely follow an index value under some constraints, has often been considered as an important application domain for control theory. Because this problem can be conveniently viewed and formulated as an optimal decision-making problem in a highly uncertain and stochastic environment, approaches based on stochastic optimal control methods are particularly pertinent. Since stochastic optimal control problems cannot be solved exactly except in very simple cases, approximations are required in most practical problems to obtain good suboptimal policies. In this paper, we present a procedure for finding a suboptimal solution to the constrained index tracking problem based on approximate dynamic programming. Illustrative simulation results show that this procedure works well when applied to a set of real financial market data.

Benefits of Using Imperfect Information in Controlling an M/M/1 Queueing System

  • Nam, Ick-Hyun
    • Management Science and Financial Engineering
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    • 제1권1호
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    • pp.1-19
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    • 1995
  • In this paper, we analyze an M / M / 1 queueing system where there are incentive conflicts among customers. Self-interested customers' decisions whether to join the system or not may not necessarily induce a socially optimal congestion level. As a way to alleviate the over-congestion, toll imposition was used in Naor's paper [3]. Instead of using a toll mechanism, we study the usefulness of imperfect information on system state (queue size, for example) as a way to reduce the over-congestion by self-interested customers. The main conclusion of this paper is that by purposefully giving fuzzy or imperfect information on the current queue size we can improve the congestion in the system. This result might look contradictory to rough intuition since perfect information should give better performance than imperfect information. We show how this idea is verified. In deriving this result, we use the concept of Nash equilibrium (pure and mixed strategy) as introduced in game theory. In some real situations, using imperfect information is easier to apply than imposing a toll, and thus the result of this paper has practical implications.

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Efficient Extraction of Hierarchically Structured Rules Using Rough Sets

  • Lee, Chul-Heui;Seo, Seon-Hak
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • 제4권2호
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    • pp.205-210
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    • 2004
  • This paper deals with rule extraction from data using rough set theory. We construct the rule base in a hierarchical granulation structure by applying core as a classification criteria at each level. When more than one core exist, the coverage is used for the selection of an appropriate one among them to increase the classification rate and accuracy. In Addition, a probabilistic approach is suggested so that the partially useful information included in inconsistent data can be contributed to knowledge reduction in order to decrease the effect of the uncertainty or vagueness of data. As a result, the proposed method yields more proper and efficient rule base in compatability and size. The simulation result shows that it gives a good performance in spite of very simple rules and short conditionals.

강인한 마찰상태관측기와 RFNN을 이용한 백스테핑 제어기반 정밀 위치제어 (Backstepping Control-Based Precise Positioning Control Using Robust Friction State Observer and RFNN)

  • 여대연;한성익;이권순
    • 한국생산제조학회지
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    • 제19권3호
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    • pp.394-401
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    • 2010
  • In this article, we investigate a robust friction compensation scheme for the purpose of accomplishing precision positioning performance a servo mechanical system with nonlinear dynamic friction. To estimate the friction state and tackle robustness problem for uncertainty, a RFNN and reconstructed error compensator as well as a robust friction state observer are developed. The asymptotic stability of the series of friction compensation methodologies are verified from the Lyapunov's stability theory. Some simulations and experiments on a servo mechanical system were carried out to evaluate the effectiveness of the proposed control scheme.

Segmentation of Millimeter-wave Radiometer Image via Classuncertainty and Region-homogeneity

  • Singh, Manoj Kumar;Tiwary, U.S.;Kim, Yong-Hoon
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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    • pp.862-864
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    • 2003
  • Thresholding is a popular image segmentation method that converts a gray-level image into a binary image. The selection of optimum threshold has remained a challenge over decades. Many image segmentation techniques are developed using information about image in other space rather than the image space itself. Most of the technique based on histogram analysis information-theoretic approaches. In this paper, the criterion function for finding optimal threshold is developed using an intensity-based classuncertainty (a histogram-based property of an image) and region-homogeneity (an image morphology-based property). The theory of the optimum thresholding method is based on postulates that objects manifest themselves with fuzzy boundaries in any digital image acquired by an imaging device. The performance of the proposed method is illustrated on experimental data obtained by W-band millimeter-wave radiometer image under different noise level.

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