[SystemSafety] A Critical-System Assurance Manifesto

Peter Bishop pgb at adelard.com
Mon Dec 11 17:08:32 CET 2017


I think in this case the Bernoulli model is not concerned with
detecting faults/fixing, but about estimating the likelihood that you
will not hit a defective region in the input space (which could in
principle be the aggregate of many faults).

Peter Bishop

On 11/12/2017 14:47, Derek M Jones wrote:
> Peter,
> 
>> * Statistical Evaluation
> Chapter 1, the Urn model.
> 
> The empirical evidence is that the Urn model is not a good
> model of faults discovery.
> 
> The Urn model gives equal weight to each item it contains.
> 
> Some faults are more likely to be discovered than others, while
> other faults are very rarely seen.  This is not the Urn model
> view of the world.
> 
> The Urn model has lots of mathematical history associated with
> it and appears in all the probability text books; which makes it
> a favorite of professors.
> 
> Isn't it about time that people started using a model with a
> closer connection with reality?
> 

-- 

Peter Bishop
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