Fault Tree Analysis.ppt

FTA

1. Fault Tree Analysis
“Faultless to a fault.” -Robert Browning
Albert Hsu

2. Introduction
Fault identification, correction and tolerance to
improve design
Fault Tree Analysis
“A method to decompose it and look for situation
that might lead to failure” (Software Engineering)
Displayed the logical path from effect to cause
Fault Tree Analysis, Fall 2006

3. The Fault Tree
Begin Fault Analysis by identifying possible failures
in design operation or maintenance
Next build a graph whose nodes are failures
Single contents
System function
Entire system
Edge = relationship among nodes by logical
descriptor (AND,OR)
Fault Tree Analysis, Fall 2006

4. The Fault Tree
Figure 5.19 Portion of power plant control system
Fault Tree Analysis, Fall 2006

5. Cut-set Tree
From Fault tree to cut-set tree
To find single points of failure in complex tree
Figure 5.20 Cut-set tree generated form the fault tree
Fault Tree Analysis, Fall 2006

6. Fixing the Failure
Removeit
Add components or conditions topreventthe
input condition that cause the fault to be
executed
Add components that will recoverfrom the
damage the failure will cause
Fault Tree Analysis, Fall 2006

7. Some faults…
Time-consuming in constructing the graphs
Many systems involve many dependencies
Difficult to detect inconsistencies
Difficult to focus only on the most critical parts of
the design on high coupling systems
Not always easy to spot
Fault Tree Analysis, Fall 2006

8. Reference
Atlee, Joanne, Software Engineering Theory
and Practice, Pearson Prentice Hall, New
Jersey, ©2006, pg264-266
Fault Tree Analysis, Fall 2006