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Re: PROV-ISSUE-43 (derivation-time): Deriviation should have associated time [Conceptual Model]

From: Paul Groth <p.t.groth@vu.nl>
Date: Sun, 24 Jul 2011 19:33:42 +0200
Message-ID: <6A76BAE9-A1CC-47F7-BD20-C6345190D38B@vu.nl>
CC: "Myers, Jim" <MYERSJ4@rpi.edu>, Provenance Working Group WG <public-prov-wg@w3.org>, Provenance Working Group Issue Tracker <sysbot+tracker@w3.org>
To: Khalid Belhajjame <Khalid.Belhajjame@cs.man.ac.uk>
Hi Khalid,

I don't think this is what I mean. 

It's not when the assertion was made. It's when the derivation occurred according to the asserter.

Just as with use and generation. It's the time at which these events occur according to the asserter.


On Jul 24, 2011, at 18:08, Khalid Belhajjame <Khalid.Belhajjame@cs.man.ac.uk> wrote:

> On 24/07/2011 15:35, Myers, Jim wrote:
>> (The time is not the interval over which the derivation relation is
>> valid - in the same way the time on USED is not the time when that
>> relation is valid (it would be if the semantics were 'in use during
>> interval t') - both just describe the time when an enduring relationship
>> was first formed.)
> Agreed, that what I was hinting to in my last response email to Paul. 
> The time I was referring to in my email was the validity, but Paul, I 
> think, was talking about the time where the derivation was formed.
> Which leads me to a new proposal. Instead of having the time as argument 
> to USE, GENERATION and derivation, e.g., isDerivedFrom(b1,b2,t). Would 
> it be sensible to assume, instead, that every assertion may be 
> associated with a time in which it was formed?
> Thanks, Khalid
>>  Jim
>>> -----Original Message-----
>>> From: public-prov-wg-request@w3.org [mailto:public-prov-wg-
>>> request@w3.org] On Behalf Of Khalid Belhajjame
>>> Sent: Sunday, July 24, 2011 8:27 AM
>>> To: Paul Groth
>>> Cc: Provenance Working Group WG; Provenance Working Group Issue
>> Tracker
>>> Subject: Re: PROV-ISSUE-43 (derivation-time): Deriviation should have
>>> associated time [Conceptual Model]
>>> Hi Paul,
>>> On 24/07/2011 13:13, Paul Groth wrote:
>>>> Hi Khalid
>>>> But why can't I say that a newspaper article is derived from a
>> picture at a
>>> particular time? Or for that matter over a period of time.
>>> The way I see it, is that there will be a bob representing the
>> newspaper article
>>> and another representing the picture. If there is evidence that the
>> latter is
>>> derived from the former, then the derivation will always hold between
>> those
>>> two bobs.
>>> Now, that I am writing this email, I am wondering whether we are
>> referring to
>>> the same notion of time. In your statement, isDerivedFrom(b1,b2,t), I
>> think you
>>> mean t is used to refers to the time in which the derivation assertion
>> was
>>> made, whereas what I was thinking of is the (period of) time in which
>> the
>>> derivation holds. Is that the case?
>>> Thanks, khalid
>>>> The time is when the derivation occurred not when it applies.
>>>> Thanks
>>>> Paul
>>>> On Jul 24, 2011, at 13:06, Khalid
>>> Belhajjame<Khalid.Belhajjame@cs.man.ac.uk>   wrote:
>>>>> Hi Paul,
>>>>> I think that "Use" and "Generation" should be associated with time.
>>>>> However, I don't think we should associate time to derivation.
>>>>> I would argue that isDerivedFrom(b1,b2) holds all time. Although b1
>>>>> and
>>>>> b2 may no longer exist, isDerivedFrom(b1,b2) is still valid.
>>>>> Thanks, khalid
>>>>> On 23/07/2011 16:46, Provenance Working Group Issue Tracker wrote:
>>>>>> PROV-ISSUE-43 (derivation-time): Deriviation should have
>> associated
>>>>>> time [Conceptual Model]
>>>>>> http://www.w3.org/2011/prov/track/issues/43
>>>>>> Raised by: Paul Groth
>>>>>> On product: Conceptual Model
>>>>>> Other relationships have time associated with them (e.g. use,
>>>>>> generation, control)
>>>>>> There is no optional time associated with derivation.
>>>>>> Suggested resolution is to add the following to the definition of
>>> isDerivedFrom:
>>>>>> -  May contain a "derived from time" t, the time or time intervals
>>>>>> when b1 was derived from b2
>>>>>> Example:
>>>>>> isDerivedFrom(b1,b2, t)
Received on Sunday, 24 July 2011 17:34:33 UTC

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