scram.probability: Fault Tree Probability Determination Acquired from SCRAM

In FaultTree.SCRAM: Interaction Between 'FaultTree' on R and "SCRAM"

Description

Interconnection with SCRAM by transferred XML files permits advanced calculation of exact probability of the top event via BDD analysis for cut sets.

Usage

scram.probability(DF, method="bdd", list_out=FALSE)

Arguments

DF	A fault tree dataframe such as returned from ftree.make or related add... functions. Fault tree basic elements must be either probability or exposed types, INHIBIT gates will be converted to AND. Fault tree shall not contain PRIORITY, ALARM nor VOTE gates, voting is [to be] handled by the atleast gate type.
method	A string for the calculation method to be used. Default is "bdd", only other accepted option is "mcub".
list_out	A logical indicating whether the list output from readSCRAMprobability should be returned. Alternatively for FALSE only a single probaility value will be returned.

Details

"And one ring to bind them all ..." This function calls ftree2mef, callSCRAM, and readSCRAMprobability appropriately for the entered ftree object. Temporary files for SCRAM input and output are produced in the process. Probability is for the top event of the tree. When calculated by the BDD algorithm it is regarded as exact. Since the BDD algorithm is not guaranteed to avoid exponential growth, use of "mcub" offers a reasonable estimate in most cases. The default output is a single element numeric vector with this probability value. The optional list output includes named objects for probability and cutsets. The cutsets object is a dataframe containing the minimal cutsets (prime implcants via BDD) by tag (padded with NA for lower order sets) with a column named prob holding the product of probabilities for each element of the cutset row.

Value

Returns a scalar vector (single value) which is the exact probability for the top event.

References

Rauzy, Antoine, et. al. (2013) Open PSA Model Exchange Format v2.0 open-psa.org

Limnios, Nikolaos (2007) Fault Trees ISTE Ltd.

Nicholls, David [Editor] (2005) System Reliability Toolkit Reliability information Analysis Center

O'Connor, Patrick D.T. (1991) Practical Reliability Engineering John Wiley & Sons

Fussell, J., Vesely, W.E. (1972) A New Method for Obtaining Cut Sets for Fault Trees Transactions ANS, No. 15

Ericson, Clifton A. II (2011) Fault Tree Analysis Primer CreateSpace Inc.

Vesely, W.E., Goldberg, F.F., Roberts, N.H., Haasl, D.F. (1981) Fault Tree Handbook U.S. Nuclear Regulatory Commission

Vesely, W.E., Stamatelato, M., Dugan, J., Fragola, J., Minarick, J., Railsback, J. (2002) Fault Tree Handbook with Aerospace Applications NASA

Doelp, L.C., Lee, G.K., Linney, R.E., Ormsby R.W. (1984) Quantitative fault tree analysis: Gate-by-gate method Plant/Operations Progress Volume 3, Issue 4 American Institute of Chemical Engineers

Examples

## This function is completely device dependent.

FaultTree.SCRAM documentation built on March 5, 2020, 3 a.m.