• 제목/요약/키워드: Observability analysis

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상태추정을 이용한 고 신뢰도 측정데이터 확보방안 연구 (Preparation of Reliable Measurement Data by Using State Estimation)

  • 김홍래
    • 한국산학기술학회논문지
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    • 제8권5호
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    • pp.1020-1025
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    • 2007
  • 전력시스템을 안정적이고 경제적으로 운영하기 위하여 EMS(energy management system)와 SCADA(supervisory control and data acquisition) 시스템이 사용되고 있다. EMS 내의 조류계산, 상정고장해석, 안전도해석과 같은 다양한 기능들의 신뢰성을 높이기 위해서는 정확한 데이터의 확보가 필수적이다. EMS 내에서 상태추정이 이와 같은 역할을 수행할 수 있으며, 본 논문에서는 정확한 상태추정을 위한 가관측성 해석 및 불량데이터 처리 프로그램을 개발하였다. 기본적인 알고리즘을 설명하고 사례연구를 통해 제안된 기법의 타당성을 검증하였다.

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An overview of decentralized optimal fault-tolerant supervisory control systems

  • Cho, K.H.;Lim, J.T.
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1996년도 Proceedings of the Korea Automatic Control Conference, 11th (KACC); Pohang, Korea; 24-26 Oct. 1996
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    • pp.358-361
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    • 1996
  • In this paper, we discuss decentralized optimal fault tolerant supervisory control issues on the basis of failure analysis and diagnosis from the angle of discrete event dynamic system. We address the detectability and the observability problems, and develope fault tolerant supervisory control system upon the failure analysis and diagnosis schemes. A complete min-cut is introduced and the procedure for finding the achievable or nonachievable layered optimal legal sublanguages is suggested for a preferential option among the reachable states in the controlled plant. A layered optimal supervisory control framework is proposed upon these. We extend the concept of decentralized supervisory control by considering the problem of combination of decentralized with centralized control in case pure decentralized control happens to be inadequate. We introduce the concept of locally controllable pair and present a hybrid decentralized supervisory control framework. Finally, we propose the analytical framework for a decentralized optimal fault tolerant supervisory control systems.

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클라우드 컴퓨팅 서비스의 도입특성이 조직의 성과기대 및 사용의도에 미치는 영향에 관한 연구: 혁신확산 이론 관점 (A Study on the Effect of the Introduction Characteristics of Cloud Computing Services on the Performance Expectancy and the Intention to Use: From the Perspective of the Innovation Diffusion Theory)

  • 임재수;오재인
    • Asia pacific journal of information systems
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    • 제22권3호
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    • pp.99-124
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    • 2012
  • Our society has long been talking about necessity for innovation. Since companies in particular need to carry out business innovation in their overall processes, they have attempted to apply many innovation factors on sites and become to pay more attention to their innovation. In order to achieve this goal, companies has applied various information technologies (IT) on sites as a means of innovation, and consequently IT have been greatly developed. It is natural for the field of IT to have faced another revolution which is called cloud computing, which is expected to result in innovative changes in software application via the Internet, data storing, the use of devices, and their operations. As a vehicle of innovation, cloud computing is expected to lead the changes and advancement of our society and the business world. Although many scholars have researched on a variety of topics regarding the innovation via IT, few studies have dealt with the issue of could computing as IT. Thus, the purpose of this paper is to set the variables of innovation attributes based on the previous articles as the characteristic variables and clarify how these variables affect "Performance Expectancy" of companies and the intention of using cloud computing. The result from the analysis of data collected in this study is as follows. The study utilized a research model developed on the innovation diffusion theory to identify influences on the adaptation and spreading IT for cloud computing services. Second, this study summarized the characteristics of cloud computing services as a new concept that introduces innovation at its early stage of adaptation for companies. Third, a theoretical model is provided that relates to the future innovation by suggesting variables for innovation characteristics to adopt cloud computing services. Finally, this study identified the factors affecting expectation and the intention to use the cloud computing service for the companies that consider adopting the cloud computing service. As the parameter and dependent variable respectively, the study deploys the independent variables that are aligned with the characteristics of the cloud computing services based on the innovation diffusion model, and utilizes the expectation for performance and Intention to Use based on the UTAUT theory. Independent variables for the research model include Relative Advantage, Complexity, Compatibility, Cost Saving, Trialability, and Observability. In addition, 'Acceptance for Adaptation' is applied as an adjustment variable to verify the influences on the expected performances from the cloud computing service. The validity of the research model was secured by performing factor analysis and reliability analysis. After confirmatory factor analysis is conducted using AMOS 7.0, the 20 hypotheses are verified through the analysis of the structural equation model, accepting 12 hypotheses among 20. For example, Relative Advantage turned out to have the positive effect both on Individual Performance and on Strategic Performance from the verification of hypothesis, while it showed meaningful correlation to affect Intention to Use directly. This indicates that many articles on the diffusion related Relative Advantage as the most important factor to predict the rate to accept innovation. From the viewpoint of the influence on Performance Expectancy among Compatibility and Cost Saving, Compatibility has the positive effect on both Individual Performance and on Strategic Performance, while it showed meaningful correlation with Intention to Use. However, the topic of the cloud computing service has become a strategic issue for adoption in companies, Cost Saving turns out to affect Individual Performance without a significant influence on Intention to Use. This indicates that companies expect practical performances such as time and cost saving and financial improvements through the adoption of the cloud computing service in the environment of the budget squeezing from the global economic crisis from 2008. Likewise, this positively affects the strategic performance in companies. In terms of effects, Trialability is proved to give no effects on Performance Expectancy. This indicates that the participants of the survey are willing to afford the risk from the high uncertainty caused by innovation, because they positively pursue information about new ideas as innovators and early adopter. In addition, they believe it is unnecessary to test the cloud computing service before the adoption, because there are various types of the cloud computing service. However, Observability positively affected both Individual Performance and Strategic Performance. It also showed meaningful correlation with Intention to Use. From the analysis of the direct effects on Intention to Use by innovative characteristics for the cloud computing service except the parameters, the innovative characteristics for the cloud computing service showed the positive influence on Relative Advantage, Compatibility and Observability while Complexity, Cost saving and the likelihood for the attempt did not affect Intention to Use. While the practical verification that was believed to be the most important factor on Performance Expectancy by characteristics for cloud computing service, Relative Advantage, Compatibility and Observability showed significant correlation with the various causes and effect analysis. Cost Saving showed a significant relation with Strategic Performance in companies, which indicates that the cost to build and operate IT is the burden of the management. Thus, the cloud computing service reflected the expectation as an alternative to reduce the investment and operational cost for IT infrastructure due to the recent economic crisis. The cloud computing service is not pervasive in the business world, but it is rapidly spreading all over the world, because of its inherited merits and benefits. Moreover, results of this research regarding the diffusion innovation are more or less different from those of the existing articles. This seems to be caused by the fact that the cloud computing service has a strong innovative factor that results in a new paradigm shift while most IT that are based on the theory of innovation diffusion are limited to companies and organizations. In addition, the participants in this study are believed to play an important role as innovators and early adapters to introduce the cloud computing service and to have competency to afford higher uncertainty for innovation. In conclusion, the introduction of the cloud computing service is a critical issue in the business world.

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전달정렬의 측정치 시간지연 오차보상 기법 (Measurement Time-Delay Error Compensation for Transfer Alignment)

  • 임유철;송기원;유준
    • 제어로봇시스템학회논문지
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    • 제7권11호
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    • pp.953-957
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    • 2001
  • This paper is concerned with a transfer alignment method for the SDINS under ship motions. Major error sources of transfer alignment are data transfer time-delay, lever-arm velocity and ship body flexure. Specifically, to reduce alignment errors induced by measurement time-delay effects, the error compensation method through delay state augmentation is suggested. A linearized error model for the velocity and attitude matching transfer alignment system is first derived by linearizing the nonliner measurement equation with respect to its time delay and augmenting the delay state into the conventional linear state equations. And then it is shown via observability analysis and computer simulations that the delay state can be estimated and compensated during ship motions resulting in considerably less alignment errors.

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구조물의 동특성치 예측을 위한 확장칼만필터기법의 초기치 설정에 관한 연구 (Initial value assumption for Estimation of Structural Dynamic System using Extended Kalman Filtering)

  • 정인희;양원직;강대언;오종식;박홍신;이원호
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2006년도 춘계학술발표회 논문집(I)
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    • pp.506-509
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    • 2006
  • Extended Kalman Filter iterate the prediction and the filtering based on Initial state for the next time step. EKF method for the estimation of nonlinear parameters of a structural dynamic system is necessary that initial of state vector and error covariance matrix. Because those are unknown exactly, generally selected random values. That occasion observability problem appear because of unknown initial values. In this study, for the estimation of the nonlinear parameters, a simple one degree of Freedom example is carried out by Extended Kalman Filter. And initial value assumption for Parameter Estimation of Dynamic System are developed. The result of analysis is compared with calculated standard values.

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최소총계적계수 감도를 갖는 상태공간 디지틀 필터의 합성 (Synthesis of the State-space Digital Filter with Minimum Statistical Cofficient Sensitivity)

  • 문용선;박종안
    • 한국통신학회논문지
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    • 제13권6호
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    • pp.510-520
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    • 1988
  • 無限誤長 상태 공간 디지틀 필터를 有限誤長 상태 공간 디지틀 필터로 실현할 때 量子化 誤差인 상태 공간 계수〔ABCD〕의 미소 변동에 기인한, 출력 오차 分散을 $\Delta$〔ABCD〕의 分散으로 正規化하였다. 즉, S=E을 統計的 感度로 정의하고 시스템 구조적 성질을 나타내는 可制御性 Gramian, 그리고 2차 모드 해석 방법을 상태 공간 디지틀 필터에 확장해서 最小 統計的 感度를 갖는 실현 구조를 합성하였으며 시뮬레이션을 통하여 최소 구조 합성의 유효성을 확인하였다.

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Measurement Time-Delay Error Compensation For Transfer Alignment

  • Lim, You-Chol;Song, Ki-Won;Joon Lyou
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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    • pp.486-486
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    • 2000
  • This paper is concerned with a transfer alignment method for the SDINS(StrapDown Inertial Navigation System) under ship motions. Major error sources of transfer alignment are data transfer time-delay, lever-arm velocity and ship body flexure. Specifically, to reduce alignment errors induced by measurement time-delay effects, the error compensation method through delay state augmentation is suggested. A linearized error model for the velocity and attitude matching transfer alignment system is first derived by linearizing the nonlinear measurement equation with respect to its time delay and augmenting the delay state into the conventional linear state equations. And then it is shown via observability analysis and computer simulations that the delay state can be estimated and compensated during ship motions resulting in considerably less alignment errors.

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Performance Enhancement of Low-Cost Land Navigation System for Location-Based Service

  • Cho, Seong-Yun;Choi, Wan-Sik
    • ETRI Journal
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    • 제28권2호
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    • pp.131-144
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    • 2006
  • This work demonstrates a dead-reckoning (DR) scheme for a low-cost land navigation system and a DR/GPS system design using the sigma point Kalman filter (SPKF). T hrough an observability analysis and some simulations, it is shown that the performances of a stand-alone DR system and DR/GPS system can be improved by employing the proposed DR scheme and SPKF. By using the designed DR scheme and filter, the stand-alone DR system does not have any undetectable errors occurring on the curve trajectory. And the DR/GPS system can provide a stable and seamless navigational solution even in the case where the initial heading estimation error is large, such as 160 degrees, or when the GPS signal is unavailable due to tunnels, buildings, and so on. Simulation results indicate a satisfactory performance of the proposed system.

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향수제품 소비 및 구매행동에 관한 탐색적 연구 (Exploratory Research on Perfume Consumption and Purchase Behaviors)

  • 여은아
    • 대한가정학회지
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    • 제42권9호
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    • pp.177-193
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    • 2004
  • The purpose of this study was to explore consumer behavior of perfume products. Data were collected through 7 focus group interviews with 33 female consumers whose ages ranged between the 20's and 40's. According to analysis of groups divided by age and frequency of use, some group differences were found in information source, purchase place, consideration factors, fragrance preference, etc. The study results indicated that perfume consumption behaviors could be explained in part by the innovation adoption and communication theories. Especially, relative advantage, compatibility, observability, and trialability were important factors influencing consumers' adoption of new perfume. Also, many respondents used perfume as a tool to present their own image and identity, as well as to send messages regarding their mood and condition to others.

RTL 회로를 위한 테스트 용이도 기반 비주사 설계 기법 (A Non-Scan Design-For-Test Technique for RTL Controllers/Datapaths based on Testability Analysis)

  • 김성일;양선웅;김문준;박재흥;김석윤;장훈
    • 한국정보과학회논문지:시스템및이론
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    • 제30권2호
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    • pp.99-107
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    • 2003
  • 본 논문에서는 RTL 회로에 대한 테스트 용이도 분석방식과 테스트 용이화 설계 방식을 제안한다. RTL 회로에 대하여 제어도와 관측도를 분석하고 테스트 용이도를 높이기 위하여 테스트용 멀티플렉서의 삽입 위치를 결정한다. 그리고 삽입해야 할 테스트용 멀티플렉서의 우선순위를 결정하여 우선순위가 높은 몇 개의 테스트용 멀티플렉서만을 삽입한다. 제안하는 테스트 용이화 설계 방식은 우선순위가 높은 멀티플렉서만을 삽입함으로써 면적 오버헤드를 최소할 수 있다. 실험을 통해 주사 방식을 적용했을 때보다 적은 면적 증가율을 보이며, 높은 고장 검출율과 테스트 패턴의 효율을 얻을 수 있다. 그리고 주사 방식에 비해 테스트 패턴을 삽입하는데 필요한 시간이 적음을 확인하였다.