[SystemSafety] A Critical-System Assurance Manifesto

[Derek M Jones]

Peter,

> operational profile, but there is a bit of theory that allows the
> confidence bound derived from testing to be rescaled for departures from
> the assumed profile, namely:

Do you have a reference for this?

> 
> 	pfd_OP <= max(p(i)'/p(i) pfd_Test

There is a comma (was / intended?) and right bracket missing.
> 
> Where p(i)' is the operational prob of demand i
> 
> and p(i)' is the test environment prob of demand i
> 
> The theory also shows that adding adding some extra "padding" tests to
> low probability demands reduces the sensitivity to profile change.

It would certain reduce the sensitivity to some profile changes.

-- 
Derek M. Jones           Software analysis
tel: +44 (0)1252 520667  blog:shape-of-code.coding-guidelines.com