Crow-AMSAA Discrete Model Example: Difference between revisions

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<noinclude>{{Banner RGA Examples}}
<noinclude>{{Banner RGA Examples}}
''This example appears in the [[Crow-AMSAA (NHPP)|Reliability Growth and Repairable System Analysis Reference book]]''.
''This example appears in the [[Crow-AMSAA (NHPP)|Reliability Growth and Repairable System Analysis Reference]]''.
</noinclude>
</noinclude>


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*Configuration 4 experienced 4 failures.
*Configuration 4 experienced 4 failures.


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


'''Solution'''
'''Solution'''
 
<ol>
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>.
<li>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>.
 
</li>
2) The following table displays the results for probability of failure and reliability, and these results are displayed in the next two plots.
<li>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.]]
</li>
</ol>

Revision as of 00:10, 23 April 2014

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


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.

Do the following:

  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.