Re: [SystemSafety] ARRL: A Criterion for Composable Safety and Systems Engineering

From: SPRIGGS, John J < >
Date: Tue, 24 Sep 2013 09:42:16 +0000

> A SIL level alone is not the top level safety requirement. It is worrying how often I come across people who are focused on their integrity level or assurance level to the exclusion of all else. Recently, for example, I was told by a supplier that they could not perform a required analysis because the "SWAL" they were using did not provide the data needed for it. The data were available but not listed as required for assurance in the EUROCONTROL development lifecycle, so they could not use them for assurance... I was not assured.

From: systemsafety-bounces_at_xxxxxx Sent: 24 September 2013 10:28
To: systemsafety_at_xxxxxx Cc: vincenzo.deflorio_at_xxxxxx
Subject: Re: [SystemSafety] ARRL: A Criterion for Composable Safety and Systems Engineering

Thanks for sharing your preprint. I read it with great interest but IMHO it contains a lot of unfounded statements and also some obvious errors, of which I state only the most important here:

Best regards

Jens Braband

PS These are my personal views and not necessarily that of my employer or other organizations that I sometimes represent.

Gesendet: Freitag, 13. September 2013 12:45 An: systemsafety_at_xxxxxx Betreff: [SystemSafety] ARRL: A Criterion for Composable Safety and Systems Engineering

Dear Madams, dear Sirs,

I'd like to draw your attention to the following paper: "ARRL: A Criterion for Composable Safety and Systems Engineering", which will be presented at the SASSUR (Next Generation of System Assurance Approaches for Safety-Critical Systems) workshop<> of SAFECOMP2013 on 24th September in Toulouse, France. The paper is authored by Eric Verhulst and Bernhard Sputh (Altreonic, Belgium), Jose Luis de la Vara (the Simula Research Lab, Norway), and Vincenzo De Florio (University of Antwerp, Belgium). The abstract is as follows:

"While safety engineering standards define rigorous and controllable processes for system development, safety standards' differences in distinct domains are non-negligible. This paper focuses in particular on the aviation, automotive, and railway standards, all related to the transportation market. Many are the reasons for the said differences, ranging from historical reasons, heuristic and established practices, and legal frameworks, but also from the psychological perception of the safety risks. In particular we argue that the Safety Integrity Levels are not sufficient to be used as a top level requirement for developing a safety-critical system. We argue that Quality of Service is a more generic criterion that takes the trustworthiness as perceived by users better into account. In addition, safety engineering standards provide very little guidance on how to compose safe systems from components, while this is the established engineering practice. In this paper we develop a novel concept called Assured Reliability and Resilience Level as a criterion that takes the industrial practice into account and show how it complements the Safety Integrity Level concept."
Kind regards,
Vincenzo De Florio

Vincenzo De Florio
PATS Research Group, University of Antwerp & iMinds Research Institute
Middelheimlaan 1, Building G, Room G1.11, B-2020 Antwerp
New e-mail address:                       vincenzo.deflorio_at_xxxxxx
(T) +32 3 265 3905                                               (F) +32 3 265 3777
(Twitter)                   (_at_xxxxxx
(Gtalk) vincenzo.deflorio    (WWW)<>

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Received on Tue Sep 24 2013 - 11:42:32 CEST

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