Compute the expected lifetime of a given system
Computes the expected lifetime of a system/network specified by its signature or graph structure when the components have Exponential lifetime distribution with specified rate. Useful for ordering systems/networks by expected lifetime.
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the signature vector of the system/network whose expected lifetime is to be computed.
the rate parameter of the Exponential distribution.
The system or network can be specified by means of an
igraph object, whereby each end of the system is denoted by nodes names "s" and "t" which are taken to be perfectly reliable. It is easy to construct the appropriate graph representation using the function
Alternatively, the signature may be provided instead (the other functions simply use the graph object to compute the signature).
All the functions return a single scalar value which is the expected lifetime.
Please feel free to email email@example.com with any queries or if you encounter errors when running this function.
Samaniego, F. J. (2007), System Signatures and Their Applications in Engineering Reliability, Springer.
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# Find the expected lifetime of two component series system expectedSystemLifetimeExp(graph.formula(s -- 1 -- 2 -- t)) # Find the expected lifetime of two component series system using it's signature directly expectedSignatureLifetimeExp(c(1,0)) # Find the expected lifetime of two component parallel system expectedSystemLifetimeExp(graph.formula(s -- 1:2 -- t)) # Find the expected lifetime of two component parallel system using it's signature directly expectedSignatureLifetimeExp(c(0,1))