[aadl]: Question about error model events distribution

[Denis Buzdalov]

Hi Viet Yen,

Thank you for your response. But, you know, I still have questions to
your answer.

> Let us translate that to practical terms. The sample 1 means that the
> error event occurs 1 time (within the timeframe according to the
> \lambda parameter of the Poisson distribution). The sample 100 means
> that the error event occurs 100 times.

The first question is what period of time event occurrence is
considered? This distribution shows the probability of n occurrences of
event during what period of time?

> Given the \lambda parameter,
> the Poisson distribution assigns a probability to that, e.g. the
> probability that the error event occurs 100 times.

The second question is am I right that you mean that \lambda parameter
can be set through the 'ProbabilityValue' record part of the
'EMV2::OccurrenceDistribution' property value?

If the answer is 'yes', then another question rises: how would you
set parameters for multiple-parameterized distributions (like the Normal
distribution)?

If the answer to the second question is 'no' then I would ask how would
you set the \lambda parameter?

> Another interesting distribution is the exponential one. It's
> continuous and spawns a probability distribution over the waiting
> time before the error event happened. For example, the probability
> that you're 100 time units in the OK state before the error event
> happens.

This part of your answer makes me messed up completely.

Am I right that you mean that the semantics of distribution setting
depends completely on the distribution type: you have
- the probability of occurrence in one case,
- expected count of occurrences in the other case and
- expected time on the third case?

Are you sure that it is formalized enough (e.g. in the standard text)
to be used by instruments or formal analysis?

--
Denis Buzdalov
Software Engineering Department, ISPRAS