Crow-AMSAA Discrete Model Example: Difference between revisions

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*Configuration 3 experienced 4 failures and
*Configuration 3 experienced 4 failures and
*Configuration 4 experienced 4 failures.
*Configuration 4 experienced 4 failures.


The objectives are:
The objectives are:
:1) Estimate the parameters of the Crow-AMSAA model using maximum likelihood estimation.
1) Estimate the parameters of the Crow-AMSAA model using maximum likelihood estimation.
:2) Estimate the unreliability and reliability by configuration.
2) Estimate the unreliability and reliability by configuration.


'''Solution'''


'''Solution'''
1) The parameter estimates for the Crow-AMSAA model using the [[Crow-AMSAA (NHPP)#Parameter_Estimation_for_Discrete Data|parameter estimation for discrete data]] methodology yields <math>\lambda = 0.5954\,\!</math> and <math>\beta =0.7801\,\!</math>.


:1) The solution from the [[Crow-AMSAA (NHPP)#Maximum_Likelihood_Estimators_for_Discrete_Model|MLE equations for discrete models]] yield <math>\lambda = 0.5954\,\!</math> and <math>\beta =0.7801\,\!</math>.
2) The following table displays the results for probability of failure and reliability, and these results are displayed in the next two plots.
:2) The following table displays the results for probability of failure and reliability, and these results are displayed in the next two plots.


<center>'''Estimated Failure Probability and Reliability by Configuration'''</center>
<center>'''Estimated Failure Probability and Reliability by Configuration'''</center>
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|4|| 0.190|| 0.810
|4|| 0.190|| 0.810
|}
|}


[[Image:rga5.16.png|center|400px|Estimated unreliability by configuration.]]
[[Image:rga5.16.png|center|400px|Estimated unreliability by configuration.]]


[[Image:rga5.17.png|center|400px|Estimated reliability by configuration.]]
[[Image:rga5.17.png|center|400px|Estimated reliability by configuration.]]

Revision as of 00:24, 31 January 2014

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This example appears in the Reliability Growth and Repairable System Analysis Reference book.


A one-shot system underwent reliability growth development testing for a total of 68 trials. Delayed corrective actions were incorporated after the 14th, 33rd and 48th trials. From trial 49 to trial 68, the configuration was not changed.

  • Configuration 1 experienced 5 failures,
  • Configuration 2 experienced 3 failures,
  • Configuration 3 experienced 4 failures and
  • Configuration 4 experienced 4 failures.

The objectives are: 1) Estimate the parameters of the Crow-AMSAA model using maximum likelihood estimation. 2) Estimate the unreliability and reliability by configuration.

Solution

1) The parameter estimates for the Crow-AMSAA model using the parameter estimation for discrete data methodology yields [math]\displaystyle{ \lambda = 0.5954\,\! }[/math] and [math]\displaystyle{ \beta =0.7801\,\! }[/math].

2) The following table displays the results for probability of failure and reliability, and these results are displayed in the next two plots.

Estimated Failure Probability and Reliability by Configuration
Configuration([math]\displaystyle{ i\,\! }[/math]) Estimated Failure Probability Estimated Reliability
1 0.333 0.667
2 0.234 0.766
3 0.206 0.794
4 0.190 0.810
Estimated unreliability by configuration.
Estimated reliability by configuration.