Isolation Probabilities Using Lambda Search - Cum % Column
Description
This column is listed under the Isolation Probabilities Using Lambda Search label in the Fault Group Size Percentages section of the Fault Isolation Report. Each entry in this column contains the cumulative probabiity that an isolated fault can be repaired by no more than the number of serial item replacements indicated in the corresponding row in the Size column.
Calculation
This Test limit can be calculated by summing, for each fault group, the isolated failure probability of the item with the ith highest probability (with i being the number of replacements indicated in the Size column), provided that the Lambda Search Criteria have been met. The following equation can be used to calculate this metric:
where
x
=
the specified number of replacement items (Size column)
Alternatively, this Test limit can be calculated by adding up the incremental isolation probabilities (the Test limits in the corresponding % column for all rows up to and including the current row), as is shown in the following equation:
where
x
=
the specified number of replacement items (Size column)
IsoPrL(i)
=
the probability that a failure can be repaired by replacing xitems (% column)
