• Title/Summary/Keyword: fuzzy models

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Chaotic Behavior in a Dynamic Love Model with Different External Forces

  • Bae, Youngchul
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.15 no.4
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    • pp.283-288
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    • 2015
  • In this paper, we propose a dynamic mathematical model of love involving various external forces, in order to analyze the chaotic phenomena in a love model based on Romeo and Juliet. In addition, we investigate the nonlinear phenomena in a love model with external forces using time series and phase portraits. In order to describe nonlinear phenomena precisely using time series and phase portraits, we vary the type of external force, using models such as a sine wave, chopping wave, and square wave. We also apply various different parameters in the Romeo and Juliet model to acquire chaotic dynamics.

Adaptive Bayesian Object Tracking with Histograms of Dense Local Image Descriptors

  • Kim, Minyoung
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.16 no.2
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    • pp.104-110
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    • 2016
  • Dense local image descriptors like SIFT are fruitful for capturing salient information about image, shown to be successful in various image-related tasks when formed in bag-of-words representation (i.e., histograms). In this paper we consider to utilize these dense local descriptors in the object tracking problem. A notable aspect of our tracker is that instead of adopting a point estimate for the target model, we account for uncertainty in data noise and model incompleteness by maintaining a distribution over plausible candidate models within the Bayesian framework. The target model is also updated adaptively by the principled Bayesian posterior inference, which admits a closed form within our Dirichlet prior modeling. With empirical evaluations on some video datasets, the proposed method is shown to yield more accurate tracking than baseline histogram-based trackers with the same types of features, often being superior to the appearance-based (visual) trackers.

회전체 기계전단을 위한 Hybrid 진단 시스템

  • 박홍석;강신현;이재종
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1995.10a
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    • pp.852-855
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    • 1995
  • In modern plant lndustry, dignosis system is an essential implement because a human operator cannot check the state of system all the time. The recent facility needs a computer system which is able to replace and extense the function of the human expert. Checking the state of the plant system, the computer system uses signals form sensors attached to the plant systems. But, It is difficult to predict the cause of the failure from the sensing signals. Because the relationship among the signals cannot be easily represented by mathematical models. So expert system based on a fuzzy rule and Neural network method is sugguested. Expert system decide whether aa state of the system is ordinary of failure by the evaluation of the signals. If the state of the system is unstable, expert system preprocess the signals. When fault is occurred in the machine, the expert system dignoses the state of the system and find the cause as a primary tool. If the expert system dose not find the adequate cause successfully, neural network system uses the preprocessed signals as an input and propose a cause of the failure.

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Mechanical properties of Al/Al2O3 and Al/B4C composites

  • Pandey, Vinod K.;Patel, Badri P.;Guruprasad, Siddalingappa
    • Advances in materials Research
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    • v.5 no.4
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    • pp.263-277
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    • 2016
  • Mechanical properties of $Al/Al_2O_3$ and $Al/B_4C$ composites prepared through powder metallurgy are estimated up to 50% $Al_2O_3$ and 35% $B_4C$ weight fractions using micromechanics models and experiments. The experimental Young's modulus up to 0.40 weight fraction of ceramic is found to lie closely between Ravichandran's/Hashin-Shtrikman lower/upper bounds, and close to self consistent method/Miller and Lannutti method/modified rule of mixture/fuzzy logic method single value predictions. Measured Poisson's ratio lies between rule of mixture/Ravichandran lower and upper bound/modified Ravichandran upper bounds. Experimental Charpy energy lies between Hopkin-chamis method/equivalent charpy energy/Ravichandran lower limit up to 20%, and close to the reciprocal rule of mixture for higher $Al_2O_3$ content. Rockwell hardness (RB) and Micro-hardness of $Al/Al_2O_3$ are closer to modified rule of mixture predictions.

Predicting Audit Reports Using Meta-Heuristic Algorithms

  • Valipour, Hashem;Salehi, Fatemeh;Bahrami, Mostafa
    • Journal of Distribution Science
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    • v.11 no.6
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    • pp.13-19
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    • 2013
  • Purpose - This study aims to predict the audit reports of listed companies on the Tehran Stock Exchange by using meta-heuristic algorithms. Research design, data, methodology - This applied research aims to predict auditors reports' using meta-heuristic methods (i.e., neural networks, the ANFIS, and a genetic algorithm). The sample includes all firms listed on the Tehran Stock Exchange. The research covers the seven years between 2005 and 2011. Results - The results show that the ANFIS model using fuzzy clustering and a least-squares back propagation algorithm has the best performance among the tested models, with an error rate of 4% for incorrect predictions and 96% for correct predictions. Conclusion - A decision tree was used with ten independent variables and one dependent variable the less important variables were removed, leaving only those variables with the greatest effect on auditor opinion (i.e., net-profit-to-sales ratio, current ratio, quick ratio, inventory turnover, collection period, and debt coverage ratio).

Short-Term Electrical Load Forecasting using Structure Identification of Neuro-Fuzzy Models (뉴로-퍼지 모델의 구조 학습을 이용한 단기 전력 수요 예측 시스템)

  • Park, Young-Jin;Shim, Hyun-Jeong;Wang, Bo-Hyeun
    • Proceedings of the KIEE Conference
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    • 2000.07a
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    • pp.102-106
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    • 2000
  • 본 논문은 뉴로-퍼지 모델의 구조학습을 이용하여 한 시간 앞의 전력 수요를 예측하는 체계적인 방법을 제안한다. 제안된 예측시스템은 시간 단위로 뉴로-퍼지 모델을 재학습하기 위해서 필요한 초기 구조를 요일 유형과 시간 별로 미리 생성하고, 이를 초기 구조 뱅크에 저장한다. 예측이 수행되는 시점의 요일 유형에 따라 선택된 초기 구조를 이용하여 뉴로-퍼지 모델을 초기화하고, 학습하고, 예측을 수행한다. 제안된 방법의 실효성을 검증하기 위해 1996년과 1997년의 실제 전력 수요 데이터를 이용하여 모의 실험을 수행한다. 실험결과 제안된 방법은 기존의 다층 퍼셉트론을 이용한 방법과 비교하여 예측의 정확도 측면과 신뢰도 측면에서 모두 향상된 결과를 얻는다.

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Control of Flexible Joint Robot Using Direct Adaptive Neural Networks Controller

  • Lee, In-Yong;Tack, Han-Ho;Lee, Sang-Bae;Park, Boo-Kwi
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.1 no.1
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    • pp.29-34
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    • 2001
  • This paper is devoted to investigating direct adaptive neural control of nonlinear systems with uncertain or unknown dynamic models. In the direct adaptive neural networks control area, theoretical issues of the existing backpropagation-based adaptive neural networks control schemes. The major contribution is proposing the variable index control approach, which is of great significance in the control field, and applying it to derive new stable robust adaptive neural network control schemes. This new schemes possess inherent robustness to system model uncertainty, which is not required to satisfy any matching condition. To demonstrate the feasibility of the proposed leaning algorithms and direct adaptive neural networks control schemes, intensive computer simulations were conducted based on the flexible joint robot systems and functions.

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Pedagogically-Driven Courseware Content Generation for Intelligent Tutoring Systems

  • Hadji, Hend Ben;Choi, Ho-Jin;Jemni, Mohamed
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.12 no.1
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    • pp.77-85
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    • 2012
  • This paper describes a novel approach to adaptive courseware generation. This approach adopts its structure from existing intelligent tutoring systems and introduces a new component called pedagogical scenario model to support pedagogical flexibility in the adaptation process of courseware generation system. The adaptation is carried out using Dynamic Constraint Satisfaction Problem framework, which is a variant of classical Constraint Satisfaction Problem, to deliver courseware tailored to individual learner. Such a framework provides a high level of expressiveness to deal with the particular characteristics of courseware generation problem. Further, it automatically designs a sound courseware satisfying the design constraints imposed by the domain, the pedagogical scenario and learner models.

Prediction of Vapor-Compressed Chiller Performance Using ANFIS Model (냉동기 성능 진단을 위한 적응형 뉴로퍼지(ANFIS) 모델 개발)

  • Shin, Young-Gy;Chang, Young-Soo;Kim, Young-Il
    • Proceedings of the KSME Conference
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    • 2001.11b
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    • pp.89-95
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    • 2001
  • On-site diagnosis of chiller performance is an essential step for energy saving business. The main purpose of the on-site diagnosis is to predict the COP of a target chiller. Many models based on thermodynamics background have been proposed for the purpose. However, they have to be modified from chiller to chiller and require deep insight into thermodynamics that most of field engineers are often lacking in. This study focuses on developing an easy-to-use diagnostic technique that is based on adaptive neuro-fuzzy inference system (ANFIS). Quality of the training data for ANFIS, sampled over June through September, is assessed by checking COP prediction errors. The architecture of the ANFIS, its error bounds, and collection of training data are described in detail.

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An Efficient Topology/Parameter Control in Evolutionary Design for Multi-domain Engineering Systems

  • Seo, Ki-Sung
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.5 no.2
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    • pp.108-113
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    • 2005
  • This paper suggests a control method for an efficient topology/parameter evolution in a bond graph-based GP design framework that automatically synthesizes designs for multi-domain, lumped parameter dynamic systems. We adopt a hierarchical breeding control mechanism with fitness-level-dependent differences to obtain better balancing of topology/parameter search - biased toward topological changes at low fitness levels, and toward parameter changes at high fitness levels. As a testbed for this approach in bond graph synthesis, an eigenvalue assignment problem, which is to find bond graph models exhibiting minimal distance errors from target sets of eigenvalues, was tested and showed improved performance for various sets of eigenvalues.