Re: [SystemSafety] Does "reliable" mean "safe" and or "secure" or neither?

From: Smith, Brian E. (ARC-TH) < >
Date: Sun, 24 Apr 2016 23:13:47 +0000


I, too, follow this list routinely. It’s like a graduate course in system safety.

Of particular interest are the unique challenge of verifying and validating the performance of increasingly autonomous aerial vehicles. I’ve been intrigued by the contrasts between industrial “safe states” achieved by closing a few key valves in a nuclear power plant, for example, and those more significant challenges posed by autonomous ground vehicles operating in 2-dimensional space with novel threat environments. To achieve the promise of “assured autonomy” needed for aerial vehicles not in direct control of human operators, the V&V space may be much larger (as some on this forum have observed).

The semantics of the terms that are the topic of this particular thread are all being debated in the Unmanned Aerial Systems community.

Your points P1 to P4 are well taken.

I really resonate with Phill Koopman’s paper, Challenges in Autonomous Vehicle Testing and Validation.

Brian E. Smith
Special Assistant for Aeronautics, Human Systems Integration Division, NASA Ames Research Center

Never let an airplane or a motorcycle take you somewhere your brain didn't go five seconds earlier.

Michael’s proviso also apples to the content of this message.

Organization: NASA Langley Research Center Date: Sunday, April 24, 2016 at 11:33 AM Subject: Re: [SystemSafety] Does "reliable" mean "safe" and or "secure" or neither?


I read this list regularly, but comment only rarely, and usually regret it when I do (for a wide variety of reasons, which are not relevant to enumerate here). But this long, mostly tiresome thread has prompted me to write a short response, which will simply take the form of X propositions. I believe each of the propositions is true, but will not provide any arguments to support my belief because I don't have the time to do so.

P1: The association within certain communities of the word "reliability" to mean exclusively "statistical/probabilistic assessment/prediction" has significantly hindered communication with the public at large, and with other communities.

P2: When one person (call him Jack) hears another person (call her Jill) use a word W, Jack nearly always assumes that Jill's intended definition of W is the same definition that he would intend in the same sentence.

P3: Quite often the practical effect of P2 is that Jack and Jill end up in a quarrel, with each convinced the other is wrong / stupid / ignorant / uninformed / pig-headed / ... . (Rather than cooperating to fetch a pail of water, Jack and Jill throw water on one another.)

P4: Forcing another person to adopt your own personal style of argumentation, rather than adopting your style to match the other person's style, is probably rightly called a form of intellectual bullying. Or at the very least, it is rightly called a lack of social skills.

cMh[ C. Michael Holloway | Senior Research Engineer | NASA Langley Research Center, MS 130, Hampton VA USA | Tel: +1.757.864.1701 ]

The words in this message are mine alone; neither blame nor credit NASA for them.

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