• 대한의용생체공학회:의공학회지
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• 제6권1호
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• pp.1-4
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• 1985

Background EEG signals can be represented as the sum of a conventional AR process and an innovation process. It is know that conventional estimation techniques, such as least square estimates (LSE) or Gauasian maximum likelihood estimates (MLE-G) are optimal when the innovation process satisfies the Gaussian or presumed distribution. When the data are contaminated by outliers, however, these assumptions are not met and the power spectrum estimated by conventional estimation techniques may be fatally biased. EEG signal may be affected by artifacts, which are outliers in the statistical term. So the robust filtering estimation technique is used against those artifacts and it performs well for the contaminated EEG signal.

• International Journal of Control, Automation, and Systems
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• 제4권3호
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• pp.365-371
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• 2006

This paper presents an algorithm based on a combination of Discrete Wavelet Transforms and neural networks for detection and classification of internal faults in a two-winding three-phase transformer. Fault conditions of the transformer are simulated using ATP/EMTP in order to obtain current signals. The training process for the neural network and fault diagnosis decision are implemented using toolboxes on MATLAB/Simulink. Various cases and fault types based on Thailand electricity transmission and distribution systems are studied to verify the validity of the algorithm. It is found that the proposed method gives a satisfactory accuracy, and will be particularly useful in a development of a modern differential relay for a transformer protection scheme.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 C
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• pp.861-863
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• 1998

F.I(Fault Indicator) is equipped in automatic switchs for Distibution Automation System(DAS), and plays important role of providing the information for picking out a fault section. The restrictive sentence that F.I doesn't react for the inrush current is in the F.I specification. Nevertheless F.I has sometimes mal-functioned on the DAS in Kang-Dong branch office of KEPCO for latest 2 years. This Paper Proved the causes of the mal-function, and proposed the new F.I specification and operation methods against the mal-function causes.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 전기설비
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• pp.40-42
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• 2005

송배전선로 자동화 공법과 관련한 일반적인 기술들이 이미 선진외국에 의해 많이 개발되어졌으나 선로 구성 및 지형적 특징으로 인하여 외국으로부터 기술도입을 통하여 그대로 활용하기는 어려운 실정이다. 본 연구에서는 송배전선로의 자동화 공법 기술개발 방향수립을 위하여 송배전 작업 현황 및 선진외국의 송배전 자동화 작업 신공법 기술동향을 분석하고 작업자의 안전과 직접적으로 관련이 있는 송배전 활선 작업 현황을 조사하였다. 또한 국내외 활선작업용 로봇 개발 및 적용현황을 조사 분석하고 활선작업용 로봇 개발을 위한 요소기술을 검토하였다. 이를 통하여 국내 적용 가능한 활선작업 신공법의 적용방안을 제시하였다.

• International Journal of Control, Automation, and Systems
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• 제6권1호
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• pp.109-118
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• 2008

We present two estimators for discrete non-Gaussian and nonstationary probability density estimation based on a dynamic Bayesian network (DBN). The first estimator is for off line computation and consists of a DBN whose transition distribution is represented in terms of kernel functions. The estimator parameters are the weights and shifts of the kernel functions. The parameters are determined through a recursive learning algorithm using maximum likelihood (ML) estimation. The second estimator is a DBN whose parameters form the transition probabilities. We use an asymptotically convergent, recursive, on-line algorithm to update the parameters using observation data. The DBN calculates the state probabilities using the estimated parameters. We provide examples that demonstrate the usefulness and simplicity of the two proposed estimators.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1993년도 Fifth International Fuzzy Systems Association World Congress 93
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• pp.1137-1140
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• 1993

A dynamic-structure system is one that has the flexibility to change the system configuration automatically so as to operate in an optimal manner. A conceptural model for a dynamic-structure system is presented in this paper. In this model, the interchangeable components of the overall system are grouped together. Their activity levels are evaluated by an intelligent preprocessor that is associated with the group. A knowledge-based task distribution system evaluates the activity levels and makes decisions as to how the components operating below capacity should be shared with workcells that have similar components that are overloaded. Associated decision making can be effected through fuzzy logic and particularly the compositional rule of inference. A simulation example is given to illustrate the application of dynamic structuring.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 D
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• pp.2452-2454
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• 2001

KEPRI, the research institute for KEPCO, has started developing a DAS using wireless communication networks since 1999. The wireless networks adopted Radio Link Protocol (RLP) of Personal Communication Service (PCS) as communication protocol. It is the first time that PCS is applied to data networks for DAS. The communication protocol, RLP, makes the DAS networks simple and economically affordable when they are installed at widely dispersed small cities. But, RLP has problem when it send unsolicited message. This paper describes the implementing method of a wireless network using RLP and TCP/IP Network to cope with unsolicited message problem.

• 전기학회논문지
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• 제61권1호
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• pp.1-6
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• 2012

Five smart grid projects was started with large scale at Jeju Island in South Korea from 2009, and smart-grid test-bed was started in Nov. 2010. The five projects are Smart Power Grid (SPG), Smart Renewable (SR), Smart Transportation (ST), Smart Place (SP) and Smart Electric Service (SES). Korea government constructed the smart grid public relations center at Nov. 2010 in Jeju Island and there will be continued the field operation and interface testing among five smart gird projects until May. 2013.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.21-22
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• 2007

Topology processing is indispensable basic function as it generate a real-time BUS-BRANCH model in Energy Management Systems because most application softwares such as state estimation, power flow, etc., require BUS-BRANCH circuit data. This paper propose an expert system to generate BUS-BRANCH circuit model using Artificial Intelligence technology and it is applied to 154kV distribution substations.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.31-32
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• 2007

In this paper, a fault section detection method is proposed for ungrounded system in the case of a single line-to-ground fault. A conventional method is used for faulted feeder selection according to the angular relationship between zero-sequence currents of the feeders and zero-sequence voltage of the system. Fault section detection is based on the comparison of phase angle of zero-sequence current. Proposed method has been testified in a demo system by Matlab/Simulink simulations. Based on Distribution Automation System(DAS), Feeder Remote Terminal Unit(FRTU) is used to collect those necessary data, at present a demo system is under developing using Manufacturing Message Specification (MMS) in IEC61850 standard.