applyUncertainty: Define an uncertainty deviate for a selected basic element in...
In FaultTree.SCRAM: Interaction Between 'FaultTree' on R and "SCRAM"

Description Usage Arguments Details Value References Examples

Modifies an existing fault tree with the addition of the repeated nodes.

1	applyUncertainty(DF, on, what="prob", deviate, param)

`DF`	A fault tree dataframe such as returned from ftree.make or related add... functions.
`on`	The ID of the basic element node to be defined uncertain.
`what`	A string identifying the basic-event parameter that uncertainty is to be applied to. Only default of "prob" has been implemented.
`deviate`	A string signifying the deviate to be applied. Implemented deviate types "uniform","normal","lognormal" have been implemented.
`param`	A single value, or vector of the appropriate deviate parameters completing the variation definition as discussed in Details below.

Application of the deviate has no impact on the tree visualization or functionality, except to provide input for uncertainty analysis by the SCRAM program. SCRAM is an external program that must be installed on the system. Package FaultTree.SCRAM has been developed to facilitate interoperatility between the FaultTree package and SCRAM. While the Open-PSA Model Exchange Format (MEF) defines the deviate parameters to be passed to SCRAM, this FaultTree.SCRAM implementation provides some simplification of deviate parameter entry. The mean under uncertainty (the 'what') is already obtainable in the basic element entry. So, only certain remaining information is required to form the proper set of MEF parameters. -For uniform-deviate only the size of the range is required param=([upper_bound_value]-[lower_bound_value]). This range value will be used to straddle the mean upon MEF entry. Allowing back-portability with earlier man page instructions if two values are provided in a vector for param they will be taken as a c([lower_bound_value],[upper_bound_value]) entry. -For the normal-deviate only the standard deviation value passed as the param argument. -For the lognormal-deviate only the sigma value (standard deviation of the log-transformed variates) is passed as the param argument. Allowing back-portability with earlier man page instructions if two values are provided in a vector for param they will be taken as a c([ErrFunc],[ConfLim]) entry. It may be helpful to review parameter_conversion for relationship between various parameters.

Returns the input fault tree dataframe amended with entries defining an uncertainty deviate for the probability of the selected event.

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

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

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

mytree <-ftree.make(type="or")
mytree <- addLogic(mytree, at=1, type= "and", name="A and B failed")
mytree <- addProbability(mytree, at=2, prob=.01, name="switch A failure")
mytree <- addProbability(mytree, at=2, prob=.01, name="switch B failure")
mytree <- addLogic(mytree, at=1, type= "and", name="A and C failed")
mytree <- addDuplicate(mytree, at=5, dup_id=3)
mytree <- addProbability(mytree, at=5, prob=.01, name="switch C failure")
mytree <- applyUncertainty(mytree, on=7, deviate="normal", param=c(.001))
mytree <- applyUncertainty(mytree, on=3, deviate="lognormal", param=c(10,.95))