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Re: PROV-ISSUE-8: defining generation in terms of `IVPT of'

From: Khalid Belhajjame <Khalid.Belhajjame@cs.man.ac.uk>
Date: Fri, 10 Jun 2011 22:41:22 +0100
Message-ID: <4DF28F82.2010507@cs.man.ac.uk>
To: Luc Moreau <L.Moreau@ecs.soton.ac.uk>
CC: Graham Klyne <GK@ninebynine.org>, "Myers, Jim" <MYERSJ4@rpi.edu>, "public-prov-wg@w3c.org" <public-prov-wg@w3c.org>

Hi Luc,

To me this discussion on the generation thread was interesting for 
derivation. I updated my definition of derivation using IVPT instead of 
resource.

/derivation/ is a relationship that associates an IVPT to another 
(different) IVPT specifying that the former contributed to the existence 
of the latter. The two IVPTs may be views of the same or different 
/things/. This can be captured by specializing the /derivation/ 
relationship, or by associating it with a property that specifies the 
relationship between the two IVPTs.

As the discussion on derivation continues, I expect that we will 
identify other kinds of derivations that we want to capture.

Thanks, khalid



On 10/06/2011 20:06, Luc Moreau wrote:
> Khalid,
>
> What would you want to do instead?
>
> Professor Luc Moreau
> Electronics and Computer Science
> University of Southampton
> Southampton SO17 1BJ
> United Kingdom
>
> On 10 Jun 2011, at 19:30, "Khalid Belhajjame"<Khalid.Belhajjame@cs.man.ac.uk>  wrote:
>
>> Hi Graham,
>>
>> I find the issues discussed in this thread interesting. That said, I am not sure I have a convincing answer to your question. A simple example that justifies the need for it though is:
>>
>> "tell me the history of a given egg"
>>
>> To answer the above query, you need to know what are the IVPTs that are represents views on the same egg.
>>
>> Thanks, khalid
>>
>> On 10/06/2011 18:16, Graham Klyne wrote:
>>> It's not clear to me yet that the model *needs* to distinguish these cases, even if we can recognize them.
>>>
>>> My quote of the day comes from the schema.org debate:
>>> "In my experience, metadata design efforts tend to fall into the trap of focusing more about what could be said about a topic rather than what needs to be said in order to support use cases of the consuming software."
>>> -- Henry Sivonen, http://hsivonen.iki.fi/schema-org-and-communities/
>>>
>>> #g
>>> -- 
>>>
>>>
>>> Khalid Belhajjame wrote:
>>>>    Hi Jim and Luc,
>>>>
>>>> I agree with Luc, Jim point is a good one. I find it more relevant to derivation than generation, though. Generally, derivation can be though of as a relationship that connects an IVPT of a thing to another IVPT of the same or different thing. I can only think of two options to deal with the point raised by Jim. Either:
>>>> - we add a property to IVPT that identify the thing that the IVPT gives a view about, or
>>>> - specialize the derivation relationship, by creating two sub-relationships that distinguish between the two cases.
>>>> Personally, I prefer the second one, as it spares us the problem of having to identify “thing”, at least for the moment.
>>>>
>>>> Thanks, khalid
>>>>
>>>> On 10/06/2011 08:09, Luc Moreau wrote:
>>>>> Hi Jim,
>>>>>
>>>>> *very* good questions, that's the essence of IVPT, I think.
>>>>>
>>>>> I don't have answers, and need to think about this.
>>>>>
>>>>> I was looking at Generation alone, you seem to allude to Derivation.
>>>>> Their definitions may need to be drafted together.  I will think about this.
>>>>>
>>>>> Luc
>>>>>
>>>>> On 10/06/11 02:28, Myers, Jim wrote:
>>>>>> This would mean that a heating process modifies an egg to create a warm egg, it does not transform a cold egg into a warm egg?
>>>>>>
>>>>>> Or do you mean both - a process execution can turn one thing into another, these things can be considered IVPTs of a thing that participates in the process execution/ is modified by the process execution? And in an open world assumption, a witness doesn't have to report the modified thing or can decline to identify/report either of things in IVPT roles depending on their ability to observe and the use case they wish to enable?
>>>>>>
>>>>>> ________________________________
>>>>>>
>>>>>> From: public-prov-wg-request@w3.org<mailto:public-prov-wg-request@w3.org>  on behalf of Luc Moreau
>>>>>> Sent: Thu 6/9/2011 6:44 PM
>>>>>> To: Provenance Working Group WG
>>>>>> Subject: PROV-ISSUE-8: defining generation in terms of `IVPT of'
>>>>>>
>>>>>>
>>>>>>
>>>>>> Hi all,
>>>>>>
>>>>>> - if a new thing is created, it is clear that we have a new IVPT of that thing
>>>>>>
>>>>>> if a chicken creates an egg is it just an IVPT of an egg?
>>>>>>
>>>>>> - if the thing is modified, then it is a requirement that a new view (IVPT) is generated ...
>>>>>>         otherwise, it would still be a view that existed before
>>>>>>
>>>>>> can't I say the egg was heated without reporting its cold and warm states? I.e. don't we want to be able to report that something was modified without having to report the IVPTs? A document was edited four times by different people but I don't wan't to/can't tell you what each wrote at each stage?
>>>>>>
>>>>>> - if the process execution was taking a long time to modify/create the thing, there is only one
>>>>>>     instant at which the (invariant!) IVPT appears
>>>>>>
>>>>>> I thnk we could define it that way, but if a cracking process takes time, saying the cracked egg appears instantaneously basically means you want 'cracked egg' to be defined by some threshold - the cracked egg might become more cracked over time ) invariant only in that it is always above the threshold and the instance of the creation of the IVPT relationship occurs ata  aspecific instant.
>>>>>>
>>>>>> - I think this captures well a stateful objects, where processes can modify the object, resulting in
>>>>>>     different IVPTs corresponding to the various states
>>>>>>
>>>>>> IVPTs are not a separate kind of thing and their invariance is relative. If they are truly immutable sates/snapshopts, they can only exist for an instant because some part of the state of the thing (a part we may not care about such as age) will change immediately.
>>>>>>
>>>>>> What do you think?
>>>>>>
>>>>>> http://www.w3.org/2011/prov/wiki/ConceptGeneration#Definition_of_Generation_by_Luc
>>>>>>
>>>>>> Cheers,
>>>>>> Luc
>>>>>>
>>>>>
>>>
>>>
Received on Friday, 10 June 2011 21:41:54 GMT

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