• Journal of applied mathematics & informatics
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• 제8권2호
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• pp.327-343
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• 2001

This is a survey article on finite element a posteriori error estimates with an emphasize on gradient recovery type error estimators. As an example, the error estimator based on the ZZ patch recovery technique will be discussed in some detail.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1988년도 한국자동제어학술회의논문집(국내학술편); 한국전력공사연수원, 서울; 21-22 Oct. 1988
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• pp.518-523
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• 1988

A Teaching and Operating Expert System (TOES) was designed in order to perform a task effectively which is inaccessible to man. Once an error occurs in the middle of the task operation, the automatic mode is converted into a manual mode. After recovering the error by the manual mode, the manual mode should be converted into the automatic mode. It was necessary to improve the manual mode in order to increase the availability of a man-robot system, a part of the human interface technique. Therefore, the Error Recovery Expert System must be constructed and developed.

• 대한임베디드공학회논문지
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• 제12권4호
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• pp.239-246
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• 2017

Time synchronization between distributed embedded systems in the Real Time Locating System (RTLS) based on Time Difference of Arrival (TDOA) is one of the most important factors to consider in system design. Clock jitter error between each system causes many difficulties in maintaining such a time synchronization. In this paper, we implemented a system to synchronize clocks between FPGA based distributed embedded systems using the recovery clock of CDR (clock data recovery) used in high speed serial communication to solve the clock jitter error problem. It is experimentally confirmed that the cumulative time error that occurs when the synchronization is not performed through the synchronization logic using the CDR recovery clock can be completely eliminated.

• 디지털콘텐츠학회 논문지
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• 제4권2호
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• pp.139-146
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• 2003

본 논문은 ERA(Error Recovery Agent)의 설계와 구축을 설명한다. ERA는 멀티미디어 원격 교육 시스템에서 소프트웨어 오류를 감지, 공유, 복구하기에 적합한 시스템이다. 이 시스템은 ED, ES, ER로 구성되어 있다. ED는 훅킹 기법으로 오류를 감지한다. ES는 멀티미디어 원격 교육 시스템에서 오류를 공유하는 에이전트이다. ER은 오류를 복구하는 에이전트이다. 본 논문에서는 멀티미디어 공동 작업 환경에서 하나의 오류 응용을 미디어로 취급하고 복구하는 방법을 제안한다.

• 한국정밀공학회지
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• 제17권4호
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• pp.135-141
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• 2000

The major role of temperature sensors in thermal error compensation system of machine tools is improving machining accuracy by supplying reliable temperature data on the machine structure. This paper presents a new method for fault diagnosis of temperature sensors and recovery of faulted data to establish the reliability of thermal error compensation system. The detection of fault and its location is based on the correlation coefficients among temperature data from the sensors. The multiple linear regression model which is prepared using complete normal data is also used fur the recovery of faulted data. The effectiveness of this method was tested by comparing the computer simulation results and measured data in a CNC machining center.

• 디지털콘텐츠학회 논문지
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• 제9권4호
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• pp.785-790
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• 2008

디지털 캐로절은 사용자들에게 미디어 동기화 메카니즘을 통하여 미디어 객체 공유를 가능하게 한다. 본 시스템은 공동 작업에 참여한 사용자들이 다른 참여자들에게 같은 뷰로써 공유된 미디어 또는 오류 객체들을 참조할 수 있도록 구축한다. 본 논문에서는 결함 허용을 통하여 신뢰성을 향상시키는 방법에 대해서 기술한다. ER은 분산 멀티미디어에서 하나의 소프트웨어 오류를 자동적으로 복구할 수 있는 시스템이다. 본 논문은 규칙-기반 DEVS(Discrete Event System Specification) 모델링과 시뮬레이션 기법을 사용하면서 분산 멀티미디어 상에서의 오류 복구 시스템의 성능 분석을 설명한다. DEVS에서 하나의 시스템은 시간, 입력, 상태, 출력 및 함수들을 가지고 있다.

• 한국정보처리학회논문지
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• 제6권10호
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• pp.2618-2629
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• 1999

In this paper, we describe the design and implementation of the FDRA(Fault Detection Recovery based on Agent) running on distributed multimedia environment. DOORAE is a good example for distributed multimedia and multimedia distance education system among students and teachers during lecture. It has primitive service agents. Service functions are implemented with objected oriented concept. FDRA is a multi-agent system. It has been environment, intelligent agents interact with each other, either collaboratively or non-collaboratively, to achieve their goals. The main idea is to detect an error by using polling method. This system detects an error by polling periodically the process with relation to session. And, it is to classify the type of error s automatically by using learning rules. The merit of this system is to use the same method to recovery it as it creates a session. FDRA is a system that is able to detect an error, to classify an error type, and to recover automatically a software error based on distributed multimedia environment.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2003년도 종합학술발표회 논문집 Vol.13 No.1
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• pp.403-406
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• 2003

In this paper, we have proposed a carrier recovery algorithm of OFDM/QPSK-DMR(Orthogonal Frequency Division Multiplexing/Quadrature Phase Shift Keying Modulation-Digital Microwave Radio)system using BL-PSF(Band Limited-Pulse Shaping Filter) and have analyzed the carrier phase MSE(Mean Square Error) performance of OFDM/QPSK and single carrier DMR systems. The existing OFDM/QPSK-DMR system using windowing requires training sequence or CP(Cyclic prefix) to synchronize a receive. carrier frequency. Because in the OFDM/QPSK-DMR system using BL-PSF there is no training sequence or CP(Cyclic Prefix), we also propose a carrier recovery useful to the system. The simulation results confirm that the proposed carrier recovery algorithm has the same carrier phase MSE(Mean Square Error) performance for the single carrier DMR system under AWGN(Additive White Gaussian Noise) environment.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2003년도 종합학술발표회 논문집 Vol.13 No.1
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• pp.394-397
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• 2003

In this paper, we have proposed a clock recovery algorithm of OFDM/QPSK-DMR(Orthogonal Frequency Division Multiplexing/Quadrature Phase Shift Keying Modulation-Digital Microwave Radio)system using BL-PSF(Band Limited-Pulse Shaping Filter) and have analyzed the clock phase error variance performance of OFDM/QPSK and single carrier DMR systems. The existing OFDM/QPSK-DMR system using the windowing requires training sequence or CP(Cyclic Prefix) to synchronize a receiver clock frequency Because there is no training sequence or CP(Cyclic prefix) in our proposed DMR system, the proposed clock recovery algorithm is useful to the OFDM/QPSK-DMR system using BL-PSF, The simulation results confirm that the proposed clock recovery algorithm has the same clock phase error variance performance in a single carrier DMR system under AWGN(Additive White Gaussian Noise) environment.

• 한국항행학회논문지
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• 제11권4호
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• pp.479-484
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• 2007

본 논문은 FRA(Fault Recovery Agent)의 설계와 구축을 설명한다. FRA는 홈 네트워크 환경에서 멀티미디어 원격 교육을 위한 소프트웨어 오류를 복구하기에 적합한 에이전트이다. 분산 멀티미디어 시스템 견지에서 보면, QoS의 가장 중요한 범주는 시간성, 볼륨, 신뢰성이다. 본 논문에서는 결함 허용을 통해서 신뢰성을 향상시키는 방법에 대해서 기술한다. 본 논문은 규칙-기반 DEVS 모델링과 시뮬레이션 기법을 사용하면서 분산 멀티미디어 상에서의 오류 복구 시스템의 성능 분석을 설명한다. DEVS에서 하나의 시스템은 시간, 입력, 상태, 출력 및 함수들을 가지고 있다. 제시된 방법이 기존 방법에 비하여 오류 발생률과 작업 수행 시간에 있어서 더 효율적이다.