• 대한교통학회지
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• 제22권4호
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• pp.147-158
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• 2004

SWP(Stochastic Wave Propagation: 확률파장전파) 모형은 Cellular Automata(CA) 이론을 기반으로한 간략한 차량모형을 이용하여 개별차량의 확률적 형태와 혼잡의 전파를 모사하고, 통계물리학을 기반으로 교통류를 거시적으로 해석한다. SWP모형은 이산적 시공간 구조와 정수형 자료를 이용한 프로그램 지향적 모형구조를 가지며 연산수행속도가 빨라 대규모 가로망의 실시간 시뮬레이션을 가능하게 하였다. 그러나 비현실적인 충돌회피과정으로 인한 자연발생적 혼잡(Spontaneous jam)의 형성 때문에 미시적으로는 혼잡내에서 잠금현상(Lockup)이 발생하여 혼잡내 차량의 저속을 설명할 수 없고, 거시적으로는 혼잡의 밀도와 전파속도를 설명하기 어렵다는 한계를 가지고 있다. 본 연구에서는 비현실적인 차량의 정지과정을 보다 현실적으로 모사하기 위한 정지조작규칙(SMR: Stopping Maneuver Rule)과 혼잡내에서 차량의 낮은 가속을 설명하기 위한 저가속규칙(LAR: Low Acceleration Rule)을 기존의 SWP모형인 NaSch모형에 추가하였다. 이를 통해 미시적으로 보다 현실적인 차량의 정지과정을 모사하면서 혼잡내에서 잠금현상을 방지하고, 거시적으로 혼잡의 밀도와 전파속도를 설명함으로써 보다 다양하게 연속 교통류를 구현하는 모형을 구축하였다.

• 한국통신학회논문지
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• 제18권6호
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• pp.871-880
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• 1993

전통적인 2진 가산규칙은 올림수를 발생시키고 MSB까지 올림수 전달이 발생하므로 직렬가산을 수행한다. 따라서 2진 가산에서 올림수 전달은 광의 병렬성을 최대한으로 이용할 수가 없다. MSD 수체계를 사용한 평가산기는 전통적인 2진 가산에서 발생하는 연속적인 올림수 전달을 제한하도록 제안되었다. 그러나 MSD 수체계는 MSD의 3가지 디지트를 표현하기 위하여 3가지 다른 상태로 부호화해야 한다. 본 논문에서는 SS방법을 사용하여 2-비트 가산규칙에 근거한 광병렬 가산기의 구성을 제안한다.

• International Journal of Quality Innovation
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• 제3권2호
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• pp.113-131
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• 2002

The relationships among multi-dimensional data (such as medical examination data) with ambiguity and variation are difficult to explore. The traditional approach to building a data classification system requires the formulation of rules by which the input data can be analyzed. The formulation of such rules is very difficult with large sets of input data. This paper first describes two classification approaches using back-propagation (BP) neural network and Mahalanobis distance (MD) classifier, and then proposes two classification approaches for multi-dimensional feature selection. The first one proposed is a feature selection procedure from the trained back-propagation (BP) neural network. The basic idea of this procedure is to compare the multiplication weights between input and hidden layer and hidden and output layer. In order to simplify the structure, only the multiplication weights of large absolute values are used. The second approach is Mahalanobis-Taguchi system (MTS) originally suggested by Dr. Taguchi. The MTS performs Taguchi's fractional factorial design based on the Mahalanobis distance as a performance metric. We combine the automatic thresholding with MD: it can deal with a reduced model, which is the focus of this paper In this work, two case studies will be used as examples to compare and discuss the complete and reduced models employing BP neural network and MD classifier. The implementation results show that proposed approaches are effective and powerful for the classification.

• 인터넷정보학회논문지
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• 제7권3호
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• pp.155-167
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• 2006

인터넷을 사용하는 사람들에게 그들의 관심사와 부합하는 웹 페이지를 제공하는 것은 매우 중요하다. 이러한 관점에서 본 논문은 각 웹 페이지의 주제와 연관된 정도를 계산하여 웹 페이지 군(cluster)을 형성하며, 단어빈도/문서빈도 엔트로피(entropy) 및 컴파일된 규칙을 이용하여 수집된 웹 페이지를 정제하는 주제 기반 웹 수집기를 제안한다. 실험을 통하여 주제 기반 웹 수집기에 대한 분류의 정확성, 수집의 효율성 및 수집의 일관성을 평가하였다. 첫째, C4.5, 역전패(back propagation) 및 CN2 기계학습 알고리즘으로 컴파일한 규칙을 이용하여 실험한 웹 수집기의 분류 성능은 CN2를 사용한 분류 성능이 가장 우수 하였으며, 둘째, 수집의 효율성을 측정하여 각 범주별로 최적의 주제 연관 정도에 대한 임계값을 도출할 수 있었다. 마지막으로, 제안한 수집기의 수집정도에 대한 일관성을 평가하기 위하여 서로 다른 시작 URL을 사용하여 수집된 웹 페이지들의 중첩정도를 측정하였다. 실험 결과에서 제안한 주제 기반 웹 수집기가 시작 URL에 큰 영향을 받지 않고 상당히 일관적인 수집을 수행함을 알 수 있었다.

• 산업기술연구
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• 제17권
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• pp.323-330
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• 1997

In this paper, a new approach to modeling of nonlinear systems using fuzzy theory is presented. To express the various and complex behavior of nonlinear system, we combine multiple model method with hierachical prioritized structure, and the mountain clustering technique is used in partitioning of system. TSK rule structure is adopted to form the fuzzy rules, and Back propagation algorithm is used for learning parameters in consequent parts of the rules. Also we soften the paradigm of Mamdani's inference mechanism by using Yager's S-OWA operators. Computer simulations are performed to verify the effectiveness of the proposed method.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1998년도 The Third Asian Fuzzy Systems Symposium
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• pp.453-458
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• 1998

In this paper, a new approach to modeling of nonlinear systems using fuzzy theory is presented. So as to handle a variety of nonlinearity and reflect the degree of confidence in the informations about system, we combine multiple model method with hierarchical prioritized structure. The mountain clustering technique is used in partition of system, and TSK rule structure is adopted to form the fuzzy rules. Back propagation algorithm is used for learning parameters in the rules. Computer simulations are performed to verify the effectiveness of the proposed method. It is useful for the treatment fo the nonlinear system of which the quantitative math-approach is difficult.

• Journal of Mechanical Science and Technology
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• 제14권11호
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• pp.1206-1215
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• 2000

This paper introduces the application of evolutionary fuzzy modeling (EFM) in constructing global function approximations to subsequent use in non-gradient based optimizations strategies. The fuzzy logic is employed for express the relationship between input training pattern in form of linguistic fuzzy rules. EFM is used to determine the optimal values of membership function parameters by adapting fuzzy rules available. In the study, genetic algorithms (GA's) treat a set of membership function parameters as design variables and evolve them until the mean square error between defuzzified outputs and actual target values are minimized. We also discuss the enhanced accuracy of function approximations, comparing with traditional response surface methods by using polynomial interpolation and back propagation neural networks in its ability to handle the typical benchmark problems.

• 한국통신학회논문지
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• 제17권5호
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• pp.482-494
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• 1992

In this paper, the neuro-fuzzy inferene system for the effective object recognition is studied. The proposed neuro-fuzzy inference system combines learning capability of neural network with inference process of fuzzy theory, and the system executes the fuzzy inference by neural network automatically. The proposed system consists of the antecedence neural network, the consequent neural network, and the fuzzy operational part, For dissolving the ambiguity of recognition due to input variance in the neuro-fuzzy inference system, the antecedence’s fuzzy proposition of the inference rules are automatically produced by error back propagation learining rule. Therefore, when the fuzzy inference is made, the shape of membership functions os adaptively modified according to the variation. The antecedence neural netwerk constructs a separated MNN(Model Classification Neural Network)and LNN(Line segment Classification Neural Networks)for dissolving the degradation of recognition rate. The antecedence neural network can overcome the limitation of boundary decisoion characteristics of nrural network due to the similarity of extracted features. The increased recognition rate is gained by the consequent neural network which is designed to learn inference rules for the effective system output.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 정기총회 및 추계학술대회 논문집 학회본부
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• pp.142-144
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• 1993

In this study, a Self-learning Neural-Fuzzy Networks is presented, Because of the fuzzy controller property, the designing problems of fuzzy if-then rules, membership functions and inference methods are very complex task. Thus in this paper we proposed the Neural-Fuzzy Networks composed by Sugeno and Takagi's fuzzy inference method and learned by using temporal back propagation algorithm. The proposed method can refine automatically the fuzzy if-then rules without human expert's knowledges. The induction motor servo system is used to demonstrate the effectiveness of the proposed control scheme and the feasibility of the acquired fuzzy controller. All results are supported by simulation.

• Asia pacific journal of information systems
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• 제11권3호
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• pp.149-164
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• 2001

In this paper, an adaptive workflow management system, called K-WFMS, is proposed. The K-WFMS integrates database system and knowledge-based system to automate business processes that are executed with complex and various business rules such as task scheduling, role resolution, and exception handling rules. The K-WFMS is adaptable in the sense that it allows its users to change workflow schema in the course of workflow execution as well as it provides rule-based modeling constructs to handle predictable exceptions during workflow modeling. The overall architecture and implementation of K-WFMS are explained, and the change propagation mechanism to maintain validity of workflow model is suggested.