Hello Again,

 

Thank you for pointing me towards the specific section in the documentation that talks about my issues. Using that, I have managed to measure the unreliability of a system. Unfortunately, I am still in the dark as to how I would measure unavailability – my first attempt involved setting a generic property to “recurrence” rather than “existence”, but I saw the IMC analysis is not even available for such a property.

 

Apart from this, I would like to know how error propagation works. The documentation I have read explains how to declare error propagation ports in an error model, but not how to connect such ports between error models. How would I make an error model react to an error that is being propagated from another error model?

 

Best Regards,

Hermann

 

From: Marco Bozzano
Sent: 12 July 2021 07:45
To: Walth, Hermann; COMPASS Consortium
Cc: Khan, Shahid
Subject: Re: [COMPASS-SUPPORT] Measuring Unreliability and Unavailability using COMPASS

 

Dear Hermann,

thank you for your interest in COMPASS.

Indeed, there are some issues with probabilistic verification and
performability analysis. This is explained in Section 6 of the COMPASS
tutorial, where a variant of the battery_sensor model is presented and
probabilistic analyses are exemplified.

Someone from RWTH Aachen University -- who implemented this part -- can
perhaps follow up with some more details.

As regards this mailing list, it is a closed support list, so there is
no public archive of it.

Best regards,

   Marco

On 09-Jul-21 15:44, Walth, Hermann wrote:
> Hello,
>
> I have been trying out COMPASS for the past few weeks, but I have not
> quite managed to get what I want out of it. I am mostly interested in
> quantitative measures such as unreliability and unavailability.
>
> Using the battery_sensor example provided with COMPASS, I could at least
> obtain a measure for unreliability in the Safety/Fault Tree Evaluation
> tab. However, this feature works by generating fault trees - I have been
> under the impression that COMPASS has more expressive power than fault
> trees. And I have no idea how to measure unavailability using COMPASS -
> the battery_sensor example is not repairable and neither are most of the
> examples provided with COMPASS.
>
> I believe the Performability/IMC Analysis feature should also be able to
> give me quantitative results, but all I can get out of it is "Long Run
> Average: 0.0". I have noticed the warning "The root component contains
> ports. Performability results are undefined.", but even with a SLIM
> model I made myself featuring no ports in its root component, I get the
> same result. I am using a property of the form "Globally, {not
> sys.is_alive} holds eventually with probability > 0.0".
>
> Is there any way to obtain measures of unreliability and more
> importantly, unavailability from COMPASS? Is the only way to get these
> measures via Fault Tree Generation?
>
> Additionally, I have been wondering if there is any kind of archive of
> this mailing list - I have been looking for one but have not found any.
>
> Best Regards,
>
> Hermann Walth
>
>
> _______________________________________________
> COMPASS-support mailing list -- compass-support@lists.rwth-aachen.de
> To unsubscribe send an email to compass-support-leave@lists.rwth-aachen.de
> https://lists.rwth-aachen.de/postorius/lists/compass-support.lists.rwth-aachen.de
>
==============================================================================
  Marco Bozzano, PhD, Researcher at FBK
    Via Sommarive 18, Povo, 38123 Trento (Italy)
    ph.: +39-0461-314367
    mobile: +39-366-6722580 (calls only, no SMS)
    bozzano@fbk.eu, http://es.fbk.eu/people/bozzano/
==============================================================================

--
--
Le informazioni contenute nella presente comunicazione sono di natura 
privata e come tali sono da considerarsi riservate ed indirizzate 
esclusivamente ai destinatari indicati e per le finalità strettamente 
legate al relativo contenuto. Se avete ricevuto questo messaggio per 
errore, vi preghiamo di eliminarlo e di inviare una comunicazione 
all’indirizzo e-mail del mittente.

--
The information transmitted is
intended only for the person or entity to which it is addressed and may
contain confidential and/or privileged material. If you received this in
error, please contact the sender and delete the material.