• 제목/요약/키워드: parameter estimate

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베이지안 추정법에 의한 소자의 수명 예측에 관한 연구 (A Study on the Lifetime Prediction of Device by the Method of Bayesian Estimate)

  • 오종환;오영환
    • 한국통신학회논문지
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    • 제19권8호
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    • pp.1446-1452
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    • 1994
  • 본 논문은 일반적으로 채택하고 있는 소자(device)의 수명분포인 와이블(Weibull) 분포를 적용하여 소자의 가속(accelerated) 수명 테스트에서 얻은 데이터, 즉 소자의 고정 시간을 이용하여 소자의 수명을 예측(prediction)하는데 필요한 보수(parameter)들을 추정 하는데 베이지안(Bayesian) 추정법을 이용하였다. 베이지안 추정법에서 모수를 추정하기 위해서는 사전정보가 있어야 하는데 본 논문에서는 사전정보 없이 현재의 정보만을 이용하여 모수를 추정하는 방법을 제안하였다. 스트레스가 온도인 경우, Arrhenius 모델을 적용하여 소자의 정상동작 상태에서의 수명을 예측 하는데 선형 추정을 하였다.

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A Note on Estimating Parameters in The Two-Parameter Weibull Distribution

  • Rahman, Mezbahur;Pearson, Larry M.
    • Journal of the Korean Data and Information Science Society
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    • 제14권4호
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    • pp.1091-1102
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    • 2003
  • The Weibull variate is commonly used as a lifetime distribution in reliability applications. Estimation of parameters is revisited in the two-parameter Weibull distribution. The method of product spacings, the method of quantile estimates and the method of least squares are applied to this distribution. A comparative study between a simple minded estimate, the maximum likelihood estimate, the product spacings estimate, the quantile estimate, the least squares estimate, and the adjusted least squares estimate is presented.

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송전선로 파라메터 정밀 예측을 위한 페이저 측정기의 응용 (Estimation Technique of Power Transmission Line Parameter by Phasor Measurement Units)

  • 조기선;박종배;신중린
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2003년도 하계학술대회 논문집 A
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    • pp.193-195
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    • 2003
  • This paper presents an approach to estimate the power transmission line parameter by phasor measurement units(PMUs), which are synchronized to 1 pps signal of GPS. Existing approaches to estimate power transmission line parameter, are mainly off-line ones, based on faults or switching events on other neighboring lines. In this paper, to obtain static and dynamic properties of power transmission line parameter in service, the prototype of pmu-based Transmission Line Parameter Monitoring System (TLPMS) is proposed. Also, an technique to estimate parameters of transmission line described as 2-port network model and the soundness of estimated parameters are addressed.

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A Maximum Power Control of IPMSM with Real-time Parameter Identification

  • Jun, Hyunwoo;Ahn, Hanwoong;Lee, Hyungwoo;Go, Sungchul;Lee, Ju
    • Journal of Electrical Engineering and Technology
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    • 제12권1호
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    • pp.110-116
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    • 2017
  • This paper proposed a new real-time parameter tracking algorithm. Unlike the convenience algorithms, the proposed real-time parameter tracking algorithm can estimate parameters through three-phase voltage and electric current without coordination transformation, and does not need information on magnetic flux. Therefore, it can estimate parameters regardless of the change according to operation point and cross-saturation effect. In addition, as the quasi-real-time parameter tracking technique can estimate parameters through the four fundamental arithmetic operations instead of complicated algorithms such as numerical value analysis technique and observer design, it can be applied to low-performance DSP. In this paper, a new real-time parameter tracking algorithm is derived from three phase equation. The validity and usefulness of the proposed inductance estimation technique is verified by simulation and experimental results.

Likelihood ratio in estimating Chi-square parameter

  • Rahman, Mezbahur
    • Journal of the Korean Data and Information Science Society
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    • 제20권3호
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    • pp.587-592
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    • 2009
  • The most frequent use of the chi-square distribution is in the area of goodness-of-t of a distribution. The likelihood ratio test is a commonly used test statistic as the maximum likelihood estimate in statistical inferences. The recently revised versions of the likelihood ratio test statistics are used in estimating the parameter in the chi-square distribution. The estimates are compared with the commonly used method of moments and the maximum likelihood estimate.

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일반화최대우도함수에 의해 추정된 평활모수에 대한 진단 (Diagnostics for Estimated Smoothing Parameter by Generalized Maximum Likelihood Function)

  • 정원태;이인석;정혜정
    • Journal of the Korean Data and Information Science Society
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    • 제7권2호
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    • pp.257-262
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    • 1996
  • 본 논문은 스플라인 희귀모형에서 평활모수를 추정할 때 사전 작업으로 영향력 진단을 하는 문제를 다룬다. 평활모수의 추정방법으로 일반화최대우도함수법을 사용할 때, 얻어지는 추정 치에 영향을 주는 관측치를 진단하는 측도를 제안하고, 찾아낸 영향력 관측치를 수정하여 올바른 평활모수 추정치를 찾는 방법을 소개한다.

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Low Parameter Sensitivity Deadbeat Direct Torque Control for Surface Mounted Permanent Magnet Synchronous Motors

  • Zhang, Xiao-Guang;Wang, Ke-Qin;Hou, Ben-Shuai
    • Journal of Power Electronics
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    • 제17권5호
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    • pp.1211-1222
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    • 2017
  • In order to decrease the parameter sensitivity of deadbeat direct torque control (DB-DTC), an improved deadbeat direct torque control method for surface mounted permanent-magnet synchronous motor (SPMSM) drives is proposed. First, the track errors of the stator flux and torque that are caused by model parameter mismatch are analyzed. Then a sliding mode observer is designed, which is able to predict the d-q axis currents of the next control period for one-step delay compensation, and to simultaneously estimate the model parameter disturbance. The estimated disturbance of this observer is used to estimate the stator resistance offline. Then the estimated resistance is required to update the designed sliding-mode observer, which can be used to estimate the inductance and permanent-magnetic flux linkage online. In addition, the flux and torque estimation of the next control period, which is unaffected by the model parameter disturbance, is achieved by using predictive d-q axis currents and estimated parameters. Hence, a low parameter sensitivity DB-DTC method is developed. Simulation and experimental results show the validity of the proposed direct control method.

2-parameter criterion에 의한 탄소성 파괴확률 예측수법 (Method of Estimate of Fracture Probability for Elastic-Plasticity by 2-Parameter Criterion)

  • 김태식;윤한용;임명환;정의정
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2003년도 춘계학술대회
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    • pp.226-234
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    • 2003
  • Put Many researcher have made much progress in studying an estimate for fracture probability of brittle materials. However, studies of the fracture probability for the elastic-plasticity have not been made yet. An estimate method for fracture probability which is grafted onto 2-parameter criterion and statistical probability analysis is not only introduced in this study, but also applied to the simple 2dimensional model and carbon steel piping to evaluate the effect of random variable.

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Estimation of pattern classification vigilance parameter using neural network

  • 손준혁;서보혁
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2004년도 심포지엄 논문집 정보 및 제어부문
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    • pp.95-97
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    • 2004
  • This paper estimates Adaptive Resonance Theory 1(ART1) as a vigilance parameter of pattern clustering algorithm. Inherent characteristics of the model are analyzed. In particular the vigilance parameter ${\rho}$ and its role in classification of patterns is examined. Our estimates show that the vigilance parameter as designed originally does not necessarily increase the number of categories with its value but can decrease also. This is against the claim of solving the stability-plasticity dilemma. However, we have proposed a modified vigilance parameter estimate criterion which takes into account the problem of subset and superset patterns and stably categorizes arbitrarily many input patterns in one list presentation when the vigilance parameter is closer to one.

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Estimation in Mixture of Shifted Poisson Distributions

  • Oh, Chang-Hyuck
    • Journal of the Korean Data and Information Science Society
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    • 제17권4호
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    • pp.1209-1217
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    • 2006
  • For the mixture of shifted Poisson distributions, a method of parameter estimation is proposed. The range of the shifted parameters are estimated first and for each shifted parameter set EM algorithm is applied to estimate the other parameters of the distribution. Among the estimated parameter sets, one with minimum likelihood for given data is to be set as the final estimate. In simulation experiments, the suggested estimation method shows to have a good performance.

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