• Title/Summary/Keyword: fuzzy set model

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Blending Precess Optimization using Fuzzy Set Theory an Neural Networks (퍼지 및 신경망을 이용한 Blending Process의 최적화)

  • 황인창;김정남;주관정
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1993.10a
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    • pp.488-492
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    • 1993
  • This paper proposes a new approach to the optimization method of a blending process with neural network. The method is based on the error backpropagation learning algorithm for neural network. Since the neural network can model an arbitrary nonlinear mapping, it is used as a system solver. A fuzzy membership function is used in parallel with the neural network to minimize the difference between measurement value and input value of neural network. As a result, we can guarantee the reliability and stability of blending process by the help of neural network and fuzzy membership function.

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A Study on Improvement of Capacity Payment using Fuzzy Theory in CBP Market (퍼지이론을 활용한 변동비 반영 전력시장의 용량요금 개선방안에 관한 연구)

  • Kim, Jong-Hyuk;Kim, Bal-Ho
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.6
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    • pp.1087-1092
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    • 2009
  • This paper presents a method for improvement of capacity payment in CBP(cost based pool) market. Capacity payments have been used as common mechanisms in various pools for compensating generators recognized to serve a for reliability purpose. Ideal pricing for capacity reserves by definition achieves a balance between economic efficiency and investment incentives. That is, prices must be kept close to costs, but not so low as to discourage investment. However, the price set is not easy. This paper concludes with market design recommendations that apply fuzzy theory for improvement of capacity payment. Following this model, market participants decided on their own based on their forecast to the market demand and the payment for it.

Vibration Diagnosis Method for Rotating Machinery Using Fuzzy Theory (퍼지이론을 이용한 회전기계의 진동진단법)

  • Yang, Bo-Suk;Jun, Soon-Ki;Kim, Ho-Jong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.20 no.5
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    • pp.1411-1418
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    • 1996
  • Large scale plants are equipped with a number of the rotating machineries which ocuupy important positions in the plant system. Therefore, the most important one is a vibraiton diagnostic thchnology which can detect quickly any abnormal symptom of operating malfunction and guve operational and inspection guides adequately. A new diagnosis method is developed in this paper, in which the fuzzy set theory is introduced to diagnose the defects of ratating machinery. The selection of memgership function and the fuzzy operation model are discussed in datail here. The systme is sucessfully used for various defacts diagnosis of rotating machinery. The result indicate that realixtic application can be builtusing this approach.

A Note on E-Learning Dynamic Assessment with Fuzzy Estimations

  • Orozova Daniela;Kim Tae-Kyun;Kim Yung-Hwan;Park Dal-Won;Seo Jong-Jin;Atanassov Krassimir;Kang Dong-Jin;Rim Seog-Hoon;Jang Lee-Chae;Ryoo Cheon-Seoung
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.5 no.3
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    • pp.179-182
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    • 2005
  • A model of an assessment module has been created, using intuitionistic fuzzy estimations, which render account on the knowledge of the trained objects. The final mark is determined on the basis of a set of evaluation units. An opportunity is offered no only fur tracing the changes of the parameters of the trainer object, but there is also an opportunity of tracing the status of the already comprehended knowledge, as well as evaluating and changing the training themes and evaluation criteria.

A Study on Trend Impact Analysis Based of Adaptive Neuro-Fuzzy Inference System

  • Yong-Gil Kim;Kang-Yeon Lee
    • International journal of advanced smart convergence
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    • v.12 no.1
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    • pp.199-207
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    • 2023
  • Trend Impact Analysis is a prominent hybrid method has been used in future studies with a modified surprise- free forecast. It considers experts' perceptions about how future events may change the surprise-free forecast. It is an advanced forecasting tool used in futures studies for identifying, understanding and analyzing the consequences of unprecedented events on future trends. In this paper, we propose an advanced mechanism to generate more justifiable estimates to the probability of occurrence of an unprecedented event as a function of time with different degrees of severity using adaptive neuro-fuzzy inference system (ANFIS). The key idea of the paper is to enhance the generic process of reasoning with fuzzy logic and neural network by adding the additional step of attributes simulation, as unprecedented events do not occur all of a sudden but rather their occurrence is affected by change in the values of a set of attributes. An ANFIS approach is used to identify the occurrence and severity of an event, depending on the values of its trigger attributes.

Pruning and Learning Fuzzy Rule-Based Classifier

  • Kim, Do-Wan;Park, Jin-Bae;Joo, Young-Hoon
    • 제어로봇시스템학회:학술대회논문집
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    • 2004.08a
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    • pp.663-667
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    • 2004
  • This paper presents new pruning and learning methods for the fuzzy rule-based classifier. The structure of the proposed classifier is framed from the fuzzy sets in the premise part of the rule and the Bayesian classifier in the consequent part. For the simplicity of the model structure, the unnecessary features for each fuzzy rule are eliminated through the iterative pruning algorithm. The quality of the feature is measured by the proposed correctness method, which is defined as the ratio of the fuzzy values for a set of the feature values on the decision region to one for all feature values. For the improvement of the classification performance, the parameters of the proposed classifier are finely adjusted by using the gradient descent method so that the misclassified feature vectors are correctly re-categorized. The cost function is determined as the squared-error between the classifier output for the correct class and the sum of the maximum output for the rest and a positive scalar. Then, the learning rules are derived from forming the gradient. Finally, the fuzzy rule-based classifier is tested on two data sets and is found to demonstrate an excellent performance.

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An Enhanced Two-Phase Fuzzy Programming Model for Multi-Objective Supplier Selection Problem

  • Fatrias, Dicky;Shimizu, Yoshiaki
    • Industrial Engineering and Management Systems
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    • v.11 no.1
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    • pp.1-10
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    • 2012
  • Supplier selection is an essential task within the purchasing function of supply chain management because it provides companies with opportunities to reduce various costs and realize stable and reliable production. However, many companies find it difficult to determine which suppliers should be targeted as each of them has varying strengths and weaknesses in performance which require careful screening by the purchaser. Moreover, information required to assess suppliers is not known precisely and typically fuzzy in nature. In this paper, therefore, fuzzy multi-objective linear programming (fuzzy MOLP) is presented under fuzzy goals: cost minimization, service level maximization and purchasing risk. To solve the problem, we introduce an enhanced two-phase approach of fuzzy linear programming for the supplier selection. In formulated problem, Analytical Hierarchy Process (AHP) is used to determine the weights of criteria, and Taguchi Loss Function is employed to quantify purchasing risk. Finally, we provide a set of alternative solution which enables decision maker (DM) to select the best compromise solution based on his/her preference. Numerical experiment is provided to demonstrate our approach.

A Study on Identification of Optimal Fuzzy Model Using Genetic Algorithm (유전알고리즘을 이용한 최적 퍼지모델의 동정에 관한연구)

  • 김기열
    • Journal of the Korean Institute of Intelligent Systems
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    • v.10 no.2
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    • pp.138-145
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    • 2000
  • A identification algorithm that finds optimal fuzzy membership functions and rule base to fuzzy model isproposed and a fuzzy controller is designed to get more accurate position and velocity control of wheeled mobile robot. This procedure that is composed of three steps has its own unique process at each step. The elements of output term set are increased at first step and then the rule base is varied according to increase of the elements. The adjusted system is in competition with system which doesn't include any increased elements. The adjusted system will be removed if the system lost. Otherwise, the control system is replaced with the adjusted system. After finished regulation of output term set and rule base, searching for input membership functions is processed with constraints and fine tuning of output membership functions is done.

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Grout Injection Control using AI Methodology (인공지능기법을 활용한 그라우트의 주입제어)

  • Lee Chung-In;Jeong Yun-Young
    • Tunnel and Underground Space
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    • v.14 no.6 s.53
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    • pp.399-410
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    • 2004
  • The utilization of AS(Artificial Intelligence) and Database could be considered as an useful access for the application of underground information from the point of a geotechnical methodology. Its detailed usage has been recently studied in many fields of geo-sciences. In this paper, the target of usage is on controlling the injection of grout which more scientific access is needed in the grouting that has been used a major method in many engineering application. As the proposals for this problem it is suggested the methodology consisting of a fuzzy-neural hybrid system and a database. The database was firstly constructed for parameters dynamically varied according to the conditions of rock mass during the injection of grout. And then the conceptional model for the fuzzy-neural hybrid system was investigated fer optimally finding the controlling range of the grout valve. The investigated model applied to four cases, and it is found that the controlling range of the grout valve was reasonably deduced corresponding to the mechanical phenomena occurred by the injection of grout. Consequently, the algorithm organizing the fuzzy-neural hybrid system and the database as a system can be considered as a tool for controlling the injection condition of grout.

DNA Based Cloud Storage Security Framework Using Fuzzy Decision Making Technique

  • Majumdar, Abhishek;Biswas, Arpita;Baishnab, Krishna Lal;Sood, Sandeep K.
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.13 no.7
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    • pp.3794-3820
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    • 2019
  • In recent years, a cloud environment with the ability to detect illegal behaviours along with a secured data storage capability is much needed. This study presents a cloud storage framework, wherein a 128-bit encryption key has been generated by combining deoxyribonucleic acid (DNA) cryptography and the Hill Cipher algorithm to make the framework unbreakable and ensure a better and secured distributed cloud storage environment. Moreover, the study proposes a DNA-based encryption technique, followed by a 256-bit secure socket layer (SSL) to secure data storage. The 256-bit SSL provides secured connections during data transmission. The data herein are classified based on different qualitative security parameters obtained using a specialized fuzzy-based classification technique. The model also has an additional advantage of being able to decide on selecting suitable storage servers from an existing pool of storage servers. A fuzzy-based technique for order of preference by similarity to ideal solution (TOPSIS) multi-criteria decision-making (MCDM) model has been employed for this, which can decide on the set of suitable storage servers on which the data must be stored and results in a reduction in execution time by keeping up the level of security to an improved grade.