• 대한기계학회논문집A
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• 제33권8호
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• pp.832-841
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• 2009

Wheels of UGV can be used to get the information about the ground. However, wheels of UGV with actively articulated suspension cannot be used as the roles because the each wheel does not remain in contact with the ground. Therefore, in this study, we proposed the indexes and models to estimate the contact wheels. First, we formulated the dynamic equations about the actively articulated suspensions and wheels. Then estimation index $I_{WTC}$ and $I_{ATC}$ were developed from the equations, and analyzed the strengths and weaknesses of each index. As the results, we developed the fuzzy rule-based estimation model additionally derived from our observations. $I_{WTC}$ model and $I_{ATC}$ model could eliminate the noise of about 60% in comparison with the result without the estimation model. Fuzzy model also could reduce the noise of about 83%. In addition, fuzzy rule-based estimation model had high sensitivity and precision as well as robustness.

• Journal of Information Processing Systems
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• 제17권5호
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• pp.918-932
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• 2021

Evaluation of the collaboration of the upstream and downstream enterprises in the manufacturing supply chain is important to improve their synergistic effect. From the supply chain perspective, this study establishes the evaluation model of the manufacturing enterprise collaboration on the basis of fuzzy entropy according to synergistic theory. Downstream enterprises carry out coordinated capital, business, and information flows as subsystems and research enterprises as composite systems. From the three subsystems, the collaboration evaluation index is selected as the order parameter. The compound fuzzy matter-element matrix is established by using its improved algorithm. Subordinate membership and standard deviation fuzzy matter-element matrixes are constructed. Index weight is determined using the entropy weight method. The closeness of each matter element is then calculated. Through a representative of the home appliance industry, namely, Gree Electric Appliances Inc. of Zhuhai, empirical analysis of data in 2011-2017 from the company and its upstream and downstream enterprise collaboration shows a good trend, but the coordinated development has not reached stability. Gree Electric Appliances Inc. of Zhuhai need to strengthen the synergy with upstream and downstream enterprises in terms of cash, business, and information flows to enhance competitiveness. Experimental results show that this method can provide precise suggestions for enterprises, improve the degree of collaboration, and accelerate the development and upgrading of the manufacturing industry.

• Journal of the Korean Data and Information Science Society
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• 제21권3호
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• pp.605-619
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• 2010

Caching of frequently accessed data in multi-hop ad hoc environment is a technique that can improve data access performance and availability. Cooperative caching, which allows sharing and coordination of cached data among several clients, can further en-hance the potential of caching techniques. In this paper, we propose a fuzzy cooperative caching scheme in mobile ad hoc networks. The cache management of the proposed caching scheme not only uses adaptively CacheData or CachePath based on data sim-ilarity and data utility, but also uses the replacement manager based on data pro t. Also, the proposed caching scheme uses a prefetch manager. When the TTL of the cached data expires, the prefetch manager evaluates the popularity index of the data. If the popularity index is larger than a threshold, the data is prefetched. Otherwise, its space is released. The performance of the proposed scheme is evaluated analytically and is compared to that of other cooperative caching schemes.

• 한국구조물진단유지관리공학회 논문집
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• 제1권2호
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• pp.131-140
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• 1997

콘크리트 교량을 저렴하고 신속하게 상태 평가를 하기 위하여 성능 지수(Performance Index)를 제안한다. 이 기법은 육안 검사에 의하여 발견된 결함의 범위와 심각도를 사용하여 콘크리트 교량의 전반적인 상태를 신속하게 등급화 하고 콘크리트 교량의 노출 조건을 고려하여 콘크리트 성능을 정량적으로 평가한다. 또한 본 연구에서는 상기한 성능 지수 기법의 타당성을 증명할 수 있는 정밀 안전 진단 시험결과를 활용하여 6개의 주요 노후화 원인을 고려하는 또 다른 성능 지수를 제안한다. 이러한 두 상태 평가 방법이 영국의 실제 교량 상태 평가 자료를 바탕으로 한 상태 평가 결과를 퍼지 집합 이론(fuzzy set theory)으로 분석한 결과와 비교하여 방법의 정당성 및 신뢰성을 논의한다.

• 대한원격탐사학회지
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• 제26권6호
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• pp.665-673
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• 2010

The role of remote sensing in phenological studies is increasingly regarded as a key in understanding large area seasonal phenomena. This paper describes the application of Moderate Resolution Imaging Spectroradiometer (MODIS) time series data for vegetation classification using seasonal variation patterns. The vegetation seasonal variation phase of Seoul and provinces in Korea was inferred using 8 day composite MODIS NDVI (Normalized Difference Vegetation Index) dataset of 2006. The seasonal vegetation classification approach is performed with reclassification of 4 categories as urban, crop land, broad-leaf and needle-leaf forest area. The BISE (Best Index Slope Extraction) filtering algorithm was applied for a smoothing processing of MODIS NDVI time series data and fuzzy classification method was used for vegetation classification. The overall accuracy of classification was 77.5% and the kappa coefficient was 0.61%, thus suggesting overall high classification accuracy.

• Nuclear Engineering and Technology
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• 제51권2호
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• pp.453-462
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• 2019

Mental workload (MWL) is a major consideration for the user interface design in nuclear power plants (NPPs). However, each MWL evaluation method has its advantages and limitations, thus the evaluation and control methods based on multi-index methods are needed. In this study, fuzzy comprehensive evaluation (FCE) theory was adopted for assessment of interface designs in NPP based on operators' MWL. An evaluation index system and membership functions were established, and the weights were given using the combination of the variation coefficient and the entropy method. The results showed that multi-index methods such as performance measures (speed of task and error rate), subjective rating (NASA-TLX) and physiological measure (eye response) can be successfully integrated in FCE for user interface design assessment. The FCE method has a correlation coefficient compared with most of the original evaluation indices. Thus, this method might be applied for developing the tool to quickly and accurately assess the different display interfaces when considering the aspect of the operators' MWL.

• 대한전자공학회논문지TC
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• 제41권10호
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• pp.69-77
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• 2004

본 논문에서는 ATM 망에서의 효율적인 트래픽 제어를 위하여 언어적인 규칙과 퍼지 추론부로 구성되는 퍼지 로직에서 퍼지 규칙을 생성하였다. 퍼지 규칙 내부에 포함된 제어 파라메터들은 주어진 성능 함수를 최소화하도록 학습된다. 즉, 전체 트래픽 도착율과 버퍼의 점유율에 따라 퍼지집합 이론을 통하여 추론한 후 그 비퍼지화값으로 접속된 트래픽에 대해 서버에서의 서비스율을 제어하도록 하였다. 또한, 생성된 퍼지 규칙의 타당성을 검증하기 위하여 MATLAB6.5에서와 온라인 빌드업으로 규칙에 대한 실험결과를 보인다. 그 결과, 전체 트래픽 도착율과 버퍼의 점유율에 따라 효율적으로 서버에서의 서비스율이 제어 됨을 확인하였다.

• 대한전기학회논문지:전력기술부문A
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• 제48권2호
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• pp.97-106
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• 1999

This paper proposes the structure and the algorithm of the Fuzzy-Neural Controller(FNNC) which is able to adapt itself to unknown plant and the change of circumstances at the Fuzzy Logic Controller(FLC) with the Neural Network. This Learning Fuzzy Logic Controller is made up of Fuzzy Logic controller in charge of a main role and Neural Network of an adaptation in variable circumstances. This construct optimal fuzzy controller applied to the 2-area load frequency control of power system, and then it would examine fitness about parameter variation of plant or variation of circumstances. And it proposes the optimal Scale factor method wsint three preformance functions( E, , U) of system dynamics of load frequency control with error back-propagation learning algorithm. Applying the controller to the model of load frequency control, it is shown that the FNNC method has better rapidity for load disturbance, reduces load frequency maximum deviation and tie line power flow deviation and minimizes reaching and settling time compared to the Optimal Fuzzy Logic Controller(OFLC) and the Optimal Control for optimzation of performance index in past control techniques.

• 한국지능시스템학회논문지
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• 제11권9호
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• pp.827-832
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• 2001

본 논문은 수치적인 데이터를 이용하여 시스템을 구성하는 퍼지 모델링에서 각각의 장점들을 유지하면서 순차적으로 성능을 개선하는 방법을 제안한다. 기존의 다양한 퍼지 모델링의 최적화 방법들은 각각의 뛰어난 최적화 기법을 이용하면서도 순차적으로 퍼지 모델의 성능을 개선하려하는 시도는 많지 않았다. 이에 본 논문에서는 각 단계별로 최적의 성능을 구현하고 이를 다음 단계에서 초기로 이용함으로써 퍼지 모델의 성능이 순차적으로 개선되는 것을 제안하였다. 이는 각각의 최적화 기법들을 지속적으로 이용함으로써 원하는 모델의 성능을 개선하고자 하는 것이다. 제안된 방법의 유용성을 Rice taste 데이터 모델에 적용하여 제안된 방법이 이전의 연구보다 좋은 결과를 보임을 알았다.

• 한국지능시스템학회논문지
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• 제9권6호
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• pp.621-626
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• 1999

In this paper a new cluster validation index which is heuristic but able to eliminate the monotonically decreasing tendency occurring in which the number of cluster c gets very large and close to the number of data points n is proposed. We review the FCM algorithm and some conventional cluster validity criteria discuss on the limiting behavior of the proposed validity index and provide some numerical examples showing the effectiveness of the proposed cluster validity index.