• 제목/요약/키워드: Data Stability

검색결과 4,052건 처리시간 0.04초

인공신경망을 이용한 평면파괴 안정성 예측 (A Prediction of the Plane Failure Stability Using Artificial Neural Networks)

  • 김방식;이성기;서재영;김광명
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2002년도 가을 학술발표회 논문집
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    • pp.513-520
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    • 2002
  • The stability analysis of rock slope can be predicted using a suitable field data but it cannot be predicted unless suitable field data was taken. In this study, artificial neural networks theory is applied to predict plane failure that has a few data. It is well known that human brain has the advantage of handling disperse and parallel distributed data efficiently. On the basis of this fact, artificial neural networks theory was developed and has been applied to various fields of science successfully In this study, error back-propagation algorithm that is one of the teaching techniques of artificial neural networks is applied to predict plane failure. In order to verify the applicability of this model, a total of 30 field data results are used. These data are used for training the artificial neural network model and compared between the predicted and the measured. The simulation results show the potentiality of utilizing the neural networks for effective safety factor prediction of plane failure. In conclusion, the well-trained artificial neural network model could be applied to predict the plane failure stability of rock slope.

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Household Over-indebtedness and Financial Vulnerability in Korea: Evidence from Credit Bureau Data

  • KIM, YOUNG IL;KIM, HYOUNG CHAN;YOO, JOO HEE
    • KDI Journal of Economic Policy
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    • 제38권3호
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    • pp.53-77
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    • 2016
  • Financial soundness in the household sector matters for financial stability and for the real economy. The level of household debt in Korea raises concern about the financial soundness of the household sector due to its size, growth rate and quality. Against this backdrop, we assess the financial vulnerability of borrowers based on an analysis of credit bureau (CB) data, in which the actual credit activities of most individuals are recorded at a high frequency in Korea. We construct over-indebtedness indicators from the CB data and then assess the predictability of forthcoming defaults. Based on the over-indebtedness indicators, we show how borrowers are distributed in terms of over-indebtedness and how the over-indebted differ from average borrowers in terms of their characteristics. Furthermore, we show how the aggregate credit risk in the household sector would change under macroeconomic distress by analyzing how each borrower's credit quality would be affected by adverse shocks. The findings of this paper may contribute to assessing household debt vulnerability and to enhancing regulatory and supervisory practices for financial stability.

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A Line-integral Fuzzy Lyapunov Functional Approach to Sampled-data Tracking Control of Takagi-Sugeno Fuzzy Systems

  • Kim, Han Sol;Joo, Young Hoon
    • Journal of Electrical Engineering and Technology
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    • 제13권6호
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    • pp.2521-2529
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    • 2018
  • This paper deals with a sampled-data tracking control problem for the Takagi-Sugeno fuzzy system with external disturbances. We derive a stability condition guaranteeing both asymptotic stability and H-infinity tracking performance by employing a newly proposed time-dependent line-integral fuzzy Lyapunov-Krasovskii functional. A new integral inequality is also introduced, by which the proposed stability condition is formulated in terms of linear matrix inequalities. Finally, the effectiveness of the proposed method is demonstrated through a simulation example.

Lateral Stability/Control Derivatives Estimation of Canard Type Airplane form Flight Test

  • Hwang, Myoung-Shin;Eun, Hee-Bong;Park, Wook-Je;Kim, Yeong-Cheol;Seong, Ki-Jeong;Kim, Eung-tae;Lee, Jong-won
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2001년도 ICCAS
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    • pp.167.1-167
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    • 2001
  • Although computational-fluid-dynamic methods and wind-tunnel testing can provide data about the aerodynamic characteristics of an aircraft, the determination of these and other characteristics from flight data plays and important role. The object of this study is the verification of overall aircraft system performance to improve the stability of vehicle. We have test the Velocity-173, canard-type airplane to obtain the stability data. We adopt the two identifications method, EKF and MLE, for the parameter estimation. The results are compared with those of conventional type airplane.

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한정된 위치의 PMU 정보를 이용한 수도권 전압안정도 감시 알고리즘 (A Voltage Stability Monitoring Algorithm using a Few PMUs in Metropolitan Area)

  • 한상욱;이병준
    • 전기학회논문지
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    • 제58권12호
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    • pp.2328-2334
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    • 2009
  • Through the development of phasor measurement units (PMU), various aspects of power system dynamic behavior could be monitored and diagnosed. Monitoring dynamic voltage stability becomes one of achievements we can obtain from PMUs. It is very important to select the method appropriate to the KEPCO system since there are many voltage stability indices. In the paper, we propose an advanced WAVI (Wide Area Voltage Stability) for monitoring dynamic voltage stability. It reflects the PMU installation plan of KEPCO, thus it is suitable for KEPCO system specially. The salient features of the proposed index are; i) it uses only PMU measurements without coupling with EMS data. ii) it is computationally unburden so that it can be applied to real-time situation. The proposed index is applied to the KEPCO test system and the result shows that it successfully predicts voltage instability through the comparative studies.

STABILITYANALYSIS OF LINGUISTIC FUZZY MODEL SYSTEMS IN STATESPACE

  • Kim, Won C.;Woo
    • 한국지능시스템학회:학술대회논문집
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    • 한국퍼지및지능시스템학회 1993년도 Fifth International Fuzzy Systems Association World Congress 93
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    • pp.953-955
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    • 1993
  • In this paper we propose a new stability theorem and a robust stability condition for linguistic fuzzy model systems in state space. First we define a stability in linear sense. After representing the fuzzy model by a system with disturbances, A necessary and sufficient condition for the stability is derived. This condition is proved to be a sufficient condition of the fuzzy model. The Q in the Lyapunov equation is iteratively adjusted by an gradient-based algorithm to improve its stability test. Finally, stability robustness bounds of a system having modeling error is derived. An example is also included to show that the stability test is powerful.

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PACE 경주용 차량의 조종안정성 개선에 대한 연구 (Study on Vehicle Stability Enhancement for the PACE Formula Vehicle)

  • 김관주;김현준;이준헌
    • 한국자동차공학회논문집
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    • 제19권1호
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    • pp.25-31
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    • 2011
  • The purpose of the study is to enhance the vehicle handling stability of the PACE formula vehicle. Required data for the dynamic analysis of the vehicle are as follows: Mass, moment of inertia, and tire's dynamic properties. Mass and moment of inertia data were calculated using Siemens NX 5.0 which results were verified with VIMF measurements of GMDAT. Dynamic data for the tire were supplied by Kumho Tire. Aerodynamic forces play an important role in the formula vehicle which forces were calculated by using Fluent. Full vehicle dynamic analysis using Carsim software has been carried out to find out the improvement of the vehicle stability by changing the shapes of the rear wing.

기록속도에 따른 BD-R의 데이터 장기보존 안정성 평가 (Long-Term Data Stability Evaluation of BD-R according to Recording Speed for Archival Application)

  • 이관용;박선주;조이형;김영주
    • 정보저장시스템학회논문집
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    • 제8권2호
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    • pp.50-55
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    • 2012
  • Optical disks are widely used in libraries and archives as digital data media due to their long-term storage stability. Though archive-grade optical disks are already available on the market, there is a relative less focusing on the reliable recording conditions. Commercial BD-R media were recorded at various recording speeds with the maximum speed of 6X, and tested at the acceleration aging conditions. Through the evaluation of long-term storage features by the data stability test, lower recording speed of 2x resulted in better long-term storage stability. In addition, degradation aspects of unstable long-term storage feature at outer region of disk were discussed.

변전소내 지역정보를 이용하여 안정도 향상을 위한 실시간 OLTC 및 커패시터 협조제어 알고리즘 (On-line coordination control of OLTC and Switched Shunt for enhancement of stability using local data in substation)

  • 강상균
    • 한국산업정보학회논문지
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    • 제17권7호
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    • pp.119-125
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    • 2012
  • 본 논문은 변전소 내에서 취득된 데이터만을 이용하여 전계통 전압안정도를 확보하기 위한 실시간 변전소내 OLTC(On-Load Tap Changer)와 S.S(Switched Shunt)와의 협조제어 알고리즘을 제안하고자 한다. 전압레벨을 일정한 값으로 유지시키기 위해서 동작하는 OLTC의 제어를 잘못하게 된다면 오히려 계통의 안정도(전압안정도) 를 해치는 결과를 나타낼 수 있다. 이 논문에서는 단일 변전소에서 취득된 데이터만으로 전체 시스템의 상태를 판단할 수 있는 Z-index를 이용하였다. Z-index를 이용하여 시스템을 normal 상태와 abnormal 상태로 구분하였고, 각 상태에 따른 협조제어 알고리즘을 제안하였다. 알고리즘 검증을 위해서 Hypersim과 matlab simulink를 이용하였다.