Paper, 16pp
Probabilistic Risk Assessment (PRA) is a method of estimating system reliability by
combining logic models of the ways systems can fail with numerical failure rates. One postulates a
failure state and systematically decomposes this state into a combination of more basic events
through a process known as Fault Tree Analysis (FTA). Failure rates are derived from vendor
specifications, historical trends, on-call reports, and many other sources. FTA has been used for
decades in the defense, aerospace, and nuclear power industries to manage risk and increase
reliability of complex engineering systems. Combining FTA with event tree analysis (ETA), one
can associate failure probabilities with consequences to clearly communicate risk both pictorially
and numerically. Basic PRA techniques can help increase the reliability and security of computer
systems.
Probabilistic Risk Assessment (PRA) is a method of estimating system reliability by
combining logic models of the ways systems can fail with numerical failure rates. One postulates a
failure state and systematically decomposes this state into a combination of more basic events
through a process known as Fault Tree Analysis (FTA). Failure rates are derived from vendor
specifications, historical trends, on-call reports, and many other sources. FTA has been used for
decades in the defense, aerospace, and nuclear power industries to manage risk and increase
reliability of complex engineering systems. Combining FTA with event tree analysis (ETA), one
can associate failure probabilities with consequences to clearly communicate risk both pictorially
and numerically. Basic PRA techniques can help increase the reliability and security of computer
systems.