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EN > FR 12 o'clock rule

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Lanarcam

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May 25, 2012, 10:27:50 AM5/25/12
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In slides about model-based design of embedded
systems.

"MBD provides formal specifications of the system
• But what properties shall we apply formal analysis to?
• One approach is to analyze structural properties
◦ E.g., no reliance on 12 o’clock rule in Stateflow
◦ Similar to table checking in SCR
◦ Prove all conditions are pairwise disjoint
◦ And collectively exhaustive"

http://www.csl.sri.com/users/rushby/slides/efftestgen.pdf

What does 12 o'clock rule mean and what could be
the translation into French?

Albert ARIBAUD

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May 25, 2012, 12:54:15 PM5/25/12
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Seems to be an ad hoc name, so it wouldn't have an obvious translation
(unless there is a french-speking community of Stateflow users within
which some sort of stadardization has been reached?)

Amicalement,
--
Albert.

Lanarcam

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May 25, 2012, 3:32:30 PM5/25/12
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I could find this explanation:

"Transitions are ordered following the 12 o’clock rule: they are
first ordered using a partial ordering on the form of their guards
(transitions guarded by an event are evaluated before transitions
guarded only by a condition, and unguarded transitions come last),
and when this ordering fails, they are ordered by following their
source clockwise starting from a 12 o’clock position."

http://www.csl.sri.com/users/rushby/papers/fase04.pdf

I thought it was a known expression among English speakers,
but it appears to mean simply that you start at the top
of the drawing and you move clockwise to order the transitions.

Albert ARIBAUD

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May 25, 2012, 5:50:27 PM5/25/12
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Actually the is a "twelve o'clock" rule known to british drivers, which
governs driving in and out of roundabouts, but it bears no relationship
to the above. See <http://www.monk1.com/resources/12oclock+roundabouts.pdf>

Amicalement,
--
Albert.

Albert ARIBAUD

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May 26, 2012, 3:28:15 AM5/26/12
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Le 25/05/2012 21:32, Lanarcam a écrit :
Actually there is a "twelve o'clock" rule known to british drivers,

Ramsman

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May 26, 2012, 4:57:43 AM5/26/12
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I'm a British driver of over forty years' experience, but have never
heard of that. The first 12 o'clock rule is also unknown to me, but then
I've no experience of Stateflow or embedded system design.

--
Peter

Albert ARIBAUD

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May 26, 2012, 5:14:05 AM5/26/12
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Thanks for correcting, and my apologies for having wrongly inferred from
the PDF above that this rule was known.

Amicalement,
--
Albert.

Ramsman

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May 26, 2012, 6:19:00 AM5/26/12
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No need for an apology Albert, there may well be many other drivers who
*have* heard of it. Judging by some drivers' behaviour at roundabouts,
there are certainly many who haven't.

> Amicalement,


--
Peter

Harlan Messinger

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May 26, 2012, 9:18:43 AM5/26/12
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On 5/25/2012 5:50 PM, Albert ARIBAUD wrote:

> Actually the is a "twelve o'clock" rule known to british drivers, which
> governs driving in and out of roundabouts, but it bears no relationship
> to the above. See <http://www.monk1.com/resources/12oclock+roundabouts.pdf>

Good LORD. Do drivers in Britain actually manage to execute all these
rules correctly? I surely knew nothing of this as I was careening around
English roundabouts.

Ramsman

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May 26, 2012, 10:46:26 AM5/26/12
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Yes, these are the principles for negotiating roundabouts properly.
Seeing the rules written down makes it seem much more complicated than
it is in reality. I used to go round this one
http://en.wikipedia.org/wiki/Magic_Roundabout_%28Hemel_Hempstead%29
quite often, and have also been round the one at Swindon (there is a
link to it in the article) without any problem. Practice makes perfect!

Not everyone actually obeys the rules, which can lead to confusion as to
what other drivers' intentions are if they are signalling incorrectly
(or not at all) or are poorly positioned.

--
Peter

Athel Cornish-Bowden

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May 26, 2012, 11:52:49 AM5/26/12
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On 2012-05-26 14:46:26 +0000, Ramsman said:

> On 26/05/2012 14:18, Harlan Messinger wrote:
>> On 5/25/2012 5:50 PM, Albert ARIBAUD wrote:
>>
>>> Actually the is a "twelve o'clock" rule known to british drivers, which
>>> governs driving in and out of roundabouts, but it bears no relationship
>>> to the above. See
>>> <http://www.monk1.com/resources/12oclock+roundabouts.pdf>
>>
>> Good LORD. Do drivers in Britain actually manage to execute all these
>> rules correctly? I surely knew nothing of this as I was careening around
>> English roundabouts.
>
> Yes, these are the principles for negotiating roundabouts properly.
> Seeing the rules written down makes it seem much more complicated than
> it is in reality.

I think that's the point. Negotiating an ordinary roundabout (not the
crazy ones you mention below) is pretty straightforward and obvious.
But as so often happens, trying to formalize straightforward rules
makes them seem very complicated.

> I used to go round this one
> http://en.wikipedia.org/wiki/Magic_Roundabout_%28Hemel_Hempstead%29
> quite often, and have also been round the one at Swindon (there is a
> link to it in the article) without any problem. Practice makes perfect!
>
> Not everyone actually obeys the rules, which can lead to confusion as
> to what other drivers' intentions are if they are signalling
> incorrectly (or not at all) or are poorly positioned.


--
athel

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