Common Cause: Half-Split Failure Probs.
What is the purpose of this algorithm?
Common Cause: Half-Split Failure Probs. is one of two pre-defined fault isolation algorithms that uses Common Cause, rather than Multiple-Failure Isolation (remember, the Analyst is not limited to using the predefined algorithms, but may edit them to create custom diagnostic solutions). Because this algorithm utilizes Common Cause isolation, it does not need to account for the idiosyncrasies of refinement testing. This algorithm uses only two Test Candidate Groupings: one for test set tests and another for output flags and internal net functions. This algorithm also uses fewer weightings (3) and cutoffs (1) than do the multiple fault algorithms, so diagnostic calculation may complete more quickly. The weightings for this algorithm favor tests that come close to half-splitting the suspect set when they pass.
How was this algorithm implemented? The full set of test selection criteria for this algorithm are as follows:
1. Test Candidate Grouping 1 of 2: Test Set Isolation
a) Candidate Test Types (1)
b) Weightings: uses algorithm defaults
c) Cutoffs: uses algorithm defaults
2. Test Candidate Grouping 2 of 2: Internal Isolation
a) Candidate Test Types (2)
b) Weightings: uses algorithm defaults
c) Cutoffs: uses algorithm defaults
1. Test Weighting 1 of 3: Sum Failure Probability
a) Priority: 50
b) Entity: Failure Probability
c) Type: Sum
d) Domain: Suspect Functions Proven
e) Best Equals: Half-Split
2. Test Weighting 2 of 3: Sum Failure Probability
a) Priority: 40
b) Entity: Failure Probability
c) Type: Sum
d) Domain: Suspect Failure Modes Proven
e) Best Equals: Half-Split
3. Test Weighting 3 of 3: Count Number of Items
a) Priority: 20
b) Entity: Number of Items
c) Type: Count
d) Domain: Suspect Functions Proven
e) Best Equals: Half-Split
C. Default Test Cutoffs (1)
1. Cutoff 1 of 1: Count Number of Items
a) Entity: Number of Items
b) Type: Count
c) Domain: Suspected Items
d) Modifier: <none>
e) Target: <none>
f) Condition: <= 1
g) Action: Terminate Sequence
