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Re: Dealing with mutable resources (PROV-O in Callimachus) - ISSUE-569

From: Luc Moreau <l.moreau@ecs.soton.ac.uk>
Date: Mon, 22 Oct 2012 16:35:53 +0100
Message-ID: <EMEW3|0bea2148c2774b06b42622adaea50b4co9LGZw08l.moreau|ecs.soton.ac.uk|508567D9.6080602@ecs.soton.ac.uk>
To: Paul Groth <p.t.groth@vu.nl>
CC: "Miles, Simon" <simon.miles@kcl.ac.uk>, Provenance Working Group WG <public-prov-wg@w3.org>
Paul
shouldn't we get it endorsed by the WG first?
Luc

On 22/10/2012 16:29, Paul Groth wrote:
> Hi Simon,
>
> It wasn't sent to him. Can you do that and cc public prov comments?
>
> I just think it's better if you send it because I'd like you to be in
> the conversation.
>
> cheers
> Paul
>
> On Mon, Oct 22, 2012 at 5:24 PM, Miles, Simon<simon.miles@kcl.ac.uk>  wrote:
>    
>> Luc, Paul,
>>
>> Sorry I could not get to this before. I see that the response is now filled out with my suggestion. Let me know if there's more that needs to be done.
>>
>> thanks,
>> Simon
>>
>> Dr Simon Miles
>> Senior Lecturer, Department of Informatics
>> Kings College London, WC2R 2LS, UK
>> +44 (0)20 7848 1166
>>
>> Automatically Adapting Source Code to Document Provenance:
>> http://eprints.dcs.kcl.ac.uk/1397/
>> ________________________________________
>> From: pgroth@gmail.com [pgroth@gmail.com] On Behalf Of Paul Groth [p.t.groth@vu.nl]
>> Sent: 22 October 2012 09:24
>> To: Luc Moreau
>> Cc: Miles, Simon; Provenance Working Group WG
>> Subject: Re: Dealing with mutable resources (PROV-O in Callimachus) - ISSUE-569
>>
>> Hi Luc,
>>
>> I think we can fill in the issue based on Simon's response. We also
>> should ask him to provide a formal acknowledgement then.
>>
>> Thanks
>> Paul
>>
>> On Mon, Oct 22, 2012 at 10:20 AM, Luc Moreau<l.moreau@ecs.soton.ac.uk>  wrote:
>>      
>>> Hi Paul and Simon,
>>>
>>> What is the situation on this issue? Simon, have you followed up as Paul
>>> suggested?
>>> I drafted an entry in the response page, is someone going to fill it up?
>>>
>>> Thanks,
>>> Luc
>>>
>>>
>>> On 10/17/2012 08:02 PM, Paul Groth wrote:
>>>
>>> Hi Simon,
>>>
>>> I'm fine with the reply, could you send it directly to him and see what he
>>> thinks?
>>>
>>> thanks!
>>> Paul
>>>
>>> On Wed, Oct 10, 2012 at 3:56 PM, Miles, Simon<simon.miles@kcl.ac.uk>  wrote:
>>>        
>>>> Hello Paul,
>>>>
>>>> I read their questions differently. I think they want to use a single
>>>> entity URI for a mutable resource, because that is what Callimachus does,
>>>> but say that it was successively altered by different agents or changed over
>>>> time. So, for example, there is an an entity ex:document, which ex:simon
>>>> contributed to in September and ex:paul contributed to in October, or a
>>>> single entity ex:flour changed (but "not in a significant way") by a baking
>>>> activity. They ask how they would express this information.
>>>>
>>>> I would answer something like:
>>>>
>>>> PROV supports the case you describe using the prov:specializationOf
>>>> relation to connect your mutable resource URI to entities representing each
>>>> revision over time. The latter don't have to exist already in Callimachus,
>>>> but may be created with unique IDs specifically to model the provenance.
>>>>
>>>> If a change in a resource's state is something to be documented in the
>>>> provenance, then that requires multiple entities. PROV entities are allowed
>>>> to be mutable, but the purpose of this is to hide information that is
>>>> unimportant, i.e. that you do not want to model in the provenance. As soon
>>>> as the timeline of the resource is divided into relevantly different periods
>>>> (e.g. before and after each contributor edited), then the mechanism to
>>>> document this in PROV is to use multiple entities. If you have a single
>>>> identifier (entity) for the mutable resource as it exists over time, through
>>>> multiple revisions, this can be connected to the set of revision entities
>>>> using the prov:specializationOf relation.
>>>>
>>>> The flour and baking example is similar. If a change is to be documented
>>>> in PROV, then multiple entities are used, e.g. the flour before and after
>>>> baking. If it is not documented, then only one entity is required. There is
>>>> no notion of a change which is "documented but not significant", because it
>>>> is unclear what significance would be in general except for the decision to
>>>> model/document it. As before, a general, mutable "flour" entity can exist
>>>> that is connected to the flour before and after baking using
>>>> prov:specializationOf. For example:
>>>>
>>>>    ex:baked prov:used ex:flour1
>>>>    ex:flour2 prov:wasGeneratedBy ex:baked
>>>>    ex:flour2 prov:wasDerivedFrom ex:flour1
>>>>    ex:flour1 prov:specializationOf ex:flour
>>>>    ex:flour2 prov:specializationOf ex:flour
>>>>
>>>> thanks,
>>>> Simon
>>>>
>>>> Dr Simon Miles
>>>> Senior Lecturer, Department of Informatics
>>>> Kings College London, WC2R 2LS, UK
>>>> +44 (0)20 7848 1166
>>>>
>>>> Transparent Provenance Derivation for User Decisions:
>>>> http://eprints.dcs.kcl.ac.uk/1400/
>>>> ________________________________________
>>>> From: pgroth@gmail.com [pgroth@gmail.com] On Behalf Of Paul Groth
>>>> [p.t.groth@vu.nl]
>>>> Sent: 10 October 2012 14:23
>>>> To: Provenance Working Group WG
>>>> Subject: Dealing with mutable resources (PROV-O in Callimachus) -
>>>> ISSUE-569
>>>>
>>>> Hi All,
>>>>
>>>> I'm trying to put together a response for James. See
>>>> http://lists.w3.org/Archives/Public/public-prov-comments/2012Oct/0001.html
>>>>
>>>> Below are my thoughts on answering the question. The central question
>>>> is how do we deal with mutable resources.
>>>>
>>>> Response/Questions
>>>>
>>>>          
>>>>> Can PROV-O be used to capture contributors to a resource over time, if
>>>>> each of the resource revisions is not represented with a unique entity?
>>>>>            
>>>> I would say the answer is yes. It's fine to write e1 wasDerivedFrom
>>>> e2, e1 wasDerivedFrom e3.
>>>>
>>>>
>>>>          
>>>>> What is the recommended way to capture these consumable resources? Must
>>>>> different entity URIs be used to represent the bag of flour before and after
>>>>> it was used? Is there any way to say an activity changed the state of a
>>>>> resource, but not in any significant way?
>>>>>            
>>>> I think this was why we wanted to introduce entity, no? The current
>>>> definition of wasGeneratedBy clearly states that it is a new entity.
>>>> The question is if this is too constraining. This seems to imply that
>>>> it is. Or I'm a misreading things?
>>>>
>>>>
>>>>          
>>>>> The way PROV-O uses qualified relationships is very interesting and
>>>>> useful. It allows simple relationships to be created (like prov:used) and if
>>>>> needed it can be clarified with a qualifiedUsage, very clever idea.
>>>>>            
>>>> Nice one prov-o team!
>>>>
>>>>
>>>>          
>>>>> Callimachus assumes that a resource may change over time and permits the
>>>>> state of a resource to be modified by a user without changing the resource's
>>>>> identifier. This means that, over time, multiple activities may contribute
>>>>> to the current state of a resource. However, distinct URIs to reference each
>>>>> of the states may not be available.
>>>>>            
>>>> I think we wanted to cater for this with scruffy provenance, no?
>>>>
>>>>
>>>>          
>>>>> The property prov:wasRevisionOf is documented[2] as a way to link entity
>>>>> revisions and combined with prov:wasGeneratedBy a way to link all the
>>>>> activities that contributed to an entity. However, since Callimachus does
>>>>> not require different URIs for each revision, this relationship could not be
>>>>> relied upon.
>>>>>            
>>>> This is the issue of wasGeneratedBy not being allowed to be on the
>>>> same resource.
>>>>
>>>>          
>>>>> Callimachus also uses prov:wasInformedBy to link a activity, that
>>>>> reverses a resource state, to the activity that created the resource state.
>>>>> Is this usage permitted by the semantics of PROV-O?
>>>>>            
>>>> I think this is fine.
>>>>          
>>>
>>>
>>>
>>> --
>>> --
>>> Dr. Paul Groth (p.t.groth@vu.nl)
>>> http://www.few.vu.nl/~pgroth/
>>> Assistant Professor
>>> - Knowledge Representation&  Reasoning Group |
>>>    Artificial Intelligence Section | Department of Computer Science
>>> - The Network Institute
>>> VU University Amsterdam
>>>
>>>
>>> --
>>> Professor Luc Moreau
>>> Electronics and Computer Science   tel:   +44 23 8059 4487
>>> University of Southampton          fax:   +44 23 8059 2865
>>> Southampton SO17 1BJ               email: l.moreau@ecs.soton.ac.uk
>>> United Kingdom                     http://www.ecs.soton.ac.uk/~lavm
>>>
>>>        
>>
>>
>> --
>> --
>> Dr. Paul Groth (p.t.groth@vu.nl)
>> http://www.few.vu.nl/~pgroth/
>> Assistant Professor
>> - Knowledge Representation&  Reasoning Group |
>>    Artificial Intelligence Section | Department of Computer Science
>> - The Network Institute
>> VU University Amsterdam
>>      
>
>
>    

-- 
Professor Luc Moreau
Electronics and Computer Science   tel:   +44 23 8059 4487
University of Southampton          fax:   +44 23 8059 2865
Southampton SO17 1BJ               email: l.moreau@ecs.soton.ac.uk
United Kingdom                     http://www.ecs.soton.ac.uk/~lavm
Received on Monday, 22 October 2012 15:36:29 UTC

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