ftree.make {FaultTree}

Fault Tree Creation

Description

ftree.make prepares an initial, single row, dataframe, which will be built upon as the tree is developed.

Usage

ftree.make(type, reversible_cond=FALSE, cond_first=TRUE, human_pbf=NULL,
		 start_id=1, system_mission_time=NULL, label="", name="", name2="",
		 description="")

Arguments

type

The logic type for the top gate. Possible gates are "or", "and", "inhibit", "priority", and "alarm". Gate types "vote" and "atleast" are disallowed in top event, place these under an OR gate.

reversible_cond

A boolean value used only by the conditional gate type indicating whether repair of the input condition is viable to the model.

cond_first

A boolean signifying whether the first child to an INHIBIT, ALARM, or PRIORITY logic gate should be taken as the condition. Alternatively, if FALSE, the second child will be taken as a condition. This is primarily a graphic display issue.

human_pbf

A probability of failure for a human to respond as needed to an alarm. This value is only used by the alarm gate.

start_id

An integer value for the starting unique ID, useful for transfer objects.

system_mission_time

An optional method for setting mission_time for the entire tree. It is also possible to set mission_time as a global variable. Use of system_mission_time in ftree.make will take precidence.

label

An identifying string for the logic gate. Use of label defines the convention for rest of tree construction.

name

An identifying string for the logic gate.

name2

A second line, if needed for the identifying string label

description

An optional string providing more detail for the resultant event.

Value

Returns a dataframe holding data, results, and connection information.

References

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

Examples

mytree <- ftree.make(type="and", name="a specific undesired event")