• Title/Summary/Keyword: 와이블 분포

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Data Analysis of Insulating Reliability Properties in Polymer for PCB (PCB용 고분자의 절연 신뢰도 특성 데이터 분석)

  • Park, Geon-Ho
    • Proceedings of the Korean Society of Computer Information Conference
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    • 2015.01a
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    • pp.289-290
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    • 2015
  • 본 연구에서는 인쇄회로기판(PCB)용 재료로 널리 사용되는 고분자에 대해서 와이블 분포 방정식의 시뮬레이션을 수행하여 절연 신뢰도 특성 데이터를 분석하였다. 와이블 분포에 대한 분석 시뮬레이션을 통하여 일반적으로 허용 절연 파괴 확률을 0.1[%] 이하라고 설정하였을 때, 첨가제 배합비를 5종으로 구분한 각 시편에 대해서 인가 전계의 허용치를 각각 계산할 수 있었다.

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Prediction of Insulation Reliability Using Weibull Distribution Simulation of Dielectric Breakdown Data (절연 파괴 데이터의 와이블 분포 시뮬레이션을 이용한 절연 신뢰도 예측)

  • Park, Geon-Ho
    • Proceedings of the Korean Society of Computer Information Conference
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    • 2012.01a
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    • pp.233-236
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    • 2012
  • 본 연구에서는 변성기용으로 사용되는 에폭시 복합체에 대해 절연 파괴 실험을 하고 그 데이터를 와이블 분포 확률을 이용해서 시뮬레이션을 하였다. 에스테르기의 기여에 의한 가교밀도 때문에 저온에서 경화제가 증가할수록 파괴강도가 증가하고 충진제를 첨가한 시료들의 파괴강도는 비충진 시료들의 경우 보다 더 낮았는데 이는 충진제 첨가가 계면을 형성하고 전하가 축적되어 분자의 이동도가 증가되고, 전계가 집중되어 전자 가속화 및 전자 사태의 성장이 초기에 도달되기 때문으로 사료된다. 또한 와이블 분포의 분석으로부터 허용 절연파괴 확률이 0.1[%]로 주어질 때, 인가 전계값은 21.5[kV/mm] 이하가 되어야 함을 확인하였다.

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A Test for Weibull Distribution and Extreme Value Distribution Based on Kullback-Leibler Information (쿨백-레이블러 정보함수에 기초한 와이블분포와 극단값 분포에 대한 적합도 검정)

  • 김종태;이우동
    • The Korean Journal of Applied Statistics
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    • v.11 no.2
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    • pp.351-362
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    • 1998
  • In this paper, a test of fit for Weibull distribution on the estimated Kullback-Leibler information is proposed. The test uses the Vasicek entropy estimates, so to compute it a window size m must first be fried, and then is obtained critical values computed by Monte Carlo simulations. The power of the proposed test under various alternatives is compares with that of ocher famous tests. The use of the test is shown in an illustrative example.

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Evaluation of Process Capability for Weibull Distribution by the RML Test (최우비(RML)검정에 의한 Weibull분포의 공정능력 평가)

  • Kim, Hong Jun;Kim, in Soo;Song, Suh Ill
    • Journal of the Society of Korea Industrial and Systems Engineering
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    • v.23 no.58
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    • pp.81-87
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    • 2000
  • 대수정규분포와 와이블분포는 비정규분포를 하는 공정특성에 반영된다. Hahn 과 Shapir(1967)의 수치 예를 통해 이러한 대수정규분포와 와이블분포를 식별하는 검정방법으로 최우비 검정(RML)을 사용하였다. 검정결과 와이블분포를 하는 공정으로 판단되어, 와이블분포 의 모수 추정은 실무에서 그래프와 수식으로도 쉽게 추정할 수 있는 수정적률추정량(MME)를 이용하여 공정 능력을 평가하였다. 공정능력의 평가 측도로 공정능력지수와 불량률(PPM)의 측도와 병행하여 나타내었다. 공정능력 평가의 결과로 와이블분포를 하는 공정을 대수정규분포로 잘못 판단함으로써 발생하는 오류를 2가지 측도로 표현함으로써 올바르게 공정능력을 판단할 수 있도록 종합적인 정보를 제시하였다.

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A Study on Statistical Characteristics of Fatigue Life of Carbon Fiber Composite (탄소섬유 복합재 피로수명의 통계적 특성 연구)

  • Joo, Young-Sik;Lee, Won-Jun;Seo, Bo-Hwi;Lim, Seung-Gyu
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.47 no.1
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    • pp.35-40
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    • 2019
  • The objective of this paper is to identify the fatigue properties of carbon-fiber composite which is widely applied for the development of aircraft structures and obtain data for full-scale fatigue test. The durability and damage tolerance evaluation of composite structures is achieved by fatigue tests and parameters such as fatigue life factor and load enhancement factor. The specimens are made with carbon-fiber/epoxy UD tape and fabric prepreg. Fatigue tests are performed with several stress ratios and lay-up patterns. The Weibull shape parameters are analyzed by Sendeckyj model and individual fatigue lives with Weibull distribution. And the fatigue life factor and load enhancement factor considering reliability are evaluated.

A Weibull Model Building Technique for Reliability Assessment with Limited failure Data (신뢰도 평가에서 제한된 데이터를 이용한 와이블분포 모형화 기법)

  • Kim, Gwang-Won
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.55 no.3
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    • pp.109-115
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    • 2006
  • The Weibull distribution is a good candidate for accurate probabilistic model with its rich shape-forming ability and relatively simple CDF(cumulative distribution function). If there are sufficient information to get convincible mean and variance for a probabilistic event, reliable parameters of the Weibull distribution can be determined uniquely. However, sufficient information is not given as usual. There needs more deliberate model building method for that case. This Paper presents an effective parameter estimation technique for Weibull distribution with limited failure data.

An Estimation of Parameters in Weibull Distribution Using Least Squares Method under Random Censoring Model (임의 중단모형에서 최소제곱법을 이용한 와이블분포의 모수 추정)

  • Lee, Woo-Dong
    • Journal of the Korean Data and Information Science Society
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    • v.7 no.2
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    • pp.263-272
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    • 1996
  • In this parer, under random censorship model, an estimation of scale and shape parameters in Weibull lifetime model is considered. Based on nonparametric estimator of survival function, the least square method is proposed. The proposed estimation method is simple and the performance of the proposed estimator is as efficient as maximum likelihood estimators. An example is presented, using field winding data. Simulation studies are performed to compare the performaces of the proposed estimator and maximum likelihood estimator.

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A generalized likelihood ratio chart for monitoring type I right-censored Weibull lifetimes (제1형 우측중도절단된 와이블 수명자료를 모니터링하는 GLR 관리도)

  • Han, Sung Won;Lee, Jaeheon
    • The Korean Journal of Applied Statistics
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    • v.30 no.5
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    • pp.647-663
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    • 2017
  • Weibull distribution is a popular distribution for modeling lifetimes because it reflects the characteristics of failure adequately and it models either increasing or decreasing failure rates simply. It is a standard method of the lifetimes test to wait until all samples failed; however, censoring can occur due to some realistic limitations. In this paper, we propose a generalized likelihood ratio (GLR) chart to monitor changes in the scale parameter for type I right-censored Weibull lifetime data. We also compare the performance of the proposed GLR chart with two CUSUM charts proposed earlier using average run length (ARL). Simulation results show that the Weibull GLR chart is effective to detect a wide range of shift sizes when the shape parameter and sample size are large and the censoring rate is not too high.

A study on estimating rifle ammunition RSR based on truncated Weibull model (우측중도절단된 와이블 분포를 이용한 소총 탄약 소요보급률 추정 연구)

  • Park, Jaeshin;Bang, Sungwan
    • The Korean Journal of Applied Statistics
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    • v.32 no.1
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    • pp.129-138
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    • 2019
  • Ammunition is an integral element of a weapon systems and in calculating fighting strength. The Korea Army utilizes the basic load (B/L) concept to supply ammunition smoothly. The required supply rate (RSR) is the basis of a B/L that is estimated from real combat data that includes a troop's mission and operation terrain. The current RSR is based on Korean War data and the sample mean has some problems in applications to modern combat. Therefore, this study used Korea Combat Training Center (KCTC) data that is similar to real combat to estimate rifle ammunition RSR. We used a quantile of truncated Weibull distribution to estimate rifle ammunition RSR considering that rifle ammunition consumption data in KCTC is truncated. As a result, we obtained a rifle ammunition RSR which covers most ammunition consumption by reflecting the individual consumption of rifle ammunition.