W3C home > Mailing lists > Public > public-prov-wg@w3.org > June 2011

Re: Definitions and provenance and invariance

From: Luc Moreau <L.Moreau@ecs.soton.ac.uk>
Date: Mon, 20 Jun 2011 12:50:25 +0100
Message-ID: <EMEW3|3ca78bf143b4d761b233ddb6b729c3d6n5JCoV08L.Moreau|ecs.soton.ac.uk|4DFF3401.8000602@ecs.soton.ac.uk>
To: Graham Klyne <GK@ninebynine.org>
CC: public-prov-wg@w3.org
You may be right,  can you explain how you understand it?
Luc

On 06/20/2011 11:22 AM, Graham Klyne wrote:
> It seems we understand the phrase "integral to identity" somewhat 
> differently, so that's a different reason not use it as part of the 
> definitions of "things" and "invariant views".  The more you say, the 
> more room there is for disagreement ...
>
> #g
> -- 
>
> Luc Moreau wrote:
>> Hi Simon and Graham,
>>
>> I added a response to Graham's comment on invariant property and 
>> identity.
>> See 
>> http://www.w3.org/2011/prov/wiki/ConceptInvariantViewOnThing#Comments
>>
>> Cheers,
>> Luc
>>
>> On 06/19/2011 12:18 PM, Simon Miles wrote:
>>> Graham,
>>>
>>> OK, thanks for the clarification. I agree with your point, and am also
>>> sympathetic to your discomfort with everything invariant being
>>> "integral to identity".
>>>
>>> Thanks,
>>> Simon
>>>
>>>
>>> On 17 June 2011 23:00, Graham Klyne<GK@ninebynine.org>  wrote:
>>>> Simon Miles wrote:
>>>>> Graham, Stian, all,
>>>>>
>>>>> I might be confused, but this seems a more complex model than the one
>>>>> proposed by Jim and Luc.  Why do we need to both a Dynamic Resource
>>>>> and a View Resource?  I can't see any meaningful difference between
>>>>> them either in Graham's definition or Stian's (helpful) concrete
>>>>> example.  What is the point of saying anything about a mutable
>>>>> property, e.g. "content of DynamicResource i0", when any assertion of
>>>>> a mutable property's value will not always hold anyway?
>>>> Speaking for myself... I used the terms "Dynamic" and "View" as 
>>>> labels to
>>>> distinguish their roles in the structure given.  I would not choose 
>>>> to model
>>>> them as different types.
>>>>
>>>> My point, expressed in terms of Stian's example, is that the notion 
>>>> we have been
>>>> calling IVP is present in the viewOf relation rather than inherent 
>>>> in the
>>>> resources themselves.  This was my point, which I think is also at 
>>>> the heart of
>>>> the proposal by Jim and Luc.
>>>>
>>>> I happen to think that the definition as proposed in the wiki at
>>>> http://www.w3.org/2011/prov/wiki/ConceptInvariantViewOnThing#ACCEPTED_at_teleconference_2011-06-16 
>>>>
>>>> is over-specified (I've added some comments there).  But having 
>>>> expressed that
>>>> reservation, I'm content to let them stand pro tem for the purposes 
>>>> of discussion.
>>>>
>>>> #g
>>>> -- 
>>>>
>>>>
>>>>> On 16 June 2011 15:39, Stian Soiland-Reyes
>>>>> <soiland-reyes@cs.manchester.ac.uk>  wrote:
>>>>>> On Tue, Jun 14, 2011 at 12:09, Graham Klyne<GK@ninebynine.org>  
>>>>>> wrote:
>>>>>>
>>>>>>> Suppose that the "Dynamic resource has a number of different 
>>>>>>> observable
>>>>>>> properties, some of which do not change over time, and others 
>>>>>>> which do.
>>>>>>>   Then the View resource would be a resource for with a similar 
>>>>>>> set of
>>>>>>> properties such that do not change over time, but correspond to 
>>>>>>> the dynamic
>>>>>>> resource properties at a given time (including properties that 
>>>>>>> do not change
>>>>>>> over time).  If the Dynamic resource does not change over time, 
>>>>>>> then it may
>>>>>>> also serve as its own view resource:  the has view property can be
>>>>>>> reflexive.
>>>>>>>
>>>>>>> The provenance resource is an assertion about the properties of 
>>>>>>> the view
>>>>>>> resource.  I believe the key requirement that we try to capture 
>>>>>>> is that the
>>>>>>> properties about which the provenance resource makes assertions are
>>>>>>> invariant - there is no assertion in the provenance resource 
>>>>>>> which is not
>>>>>>> always true of the view resource.
>>>>>> This is a very beautifully simple model which I think we should keep
>>>>>> in mind before digging too much into the exciting discussions.
>>>>>>
>>>>>>
>>>>>>
>>>>>> "simplified" for the File example:
>>>>>>
>>>>>>
>>>>>> :i0 a :DynamicResource ;
>>>>>>   :name "/home/towns.txt" ;
>>>>>>   :content [ :bytes "" ] ;
>>>>>>   :creator :Alice .
>>>>>>
>>>>>>
>>>>>> :i0View a :ViewResource ;
>>>>>>    :viewOf :i0 ;
>>>>>>    :name "/home/towns.txt" ;
>>>>>>    :creator :Alice .
>>>>>>
>>>>>>
>>>>>> # Metadata stored in filesystem
>>>>>> :i0Provenance a :ProvenanceResource ;
>>>>>>    :provenanceOf :i0View ;
>>>>>>    :account :FileSystem ;
>>>>>>    :processes (
>>>>>>       [  :agent :Alice ;
>>>>>>          :location :server1 ;
>>>>>>          :process :fileCreation ;
>>>>>>          :time "2011-06-15 18:00:01 UTC"  ]
>>>>>>     ) .
>>>>>>
>>>>>> # however the log file claims the file was created on her 
>>>>>> workstation
>>>>>> (not server), and 1 second later (clocks out of sync?)
>>>>>>
>>>>>> :i0Provenance2 a :ProvenanceResource ;
>>>>>>    :provenanceOf :i0View ;
>>>>>>    :account :ServerLogFile ;
>>>>>>    :processes (
>>>>>>       [  :agent :Alice ;
>>>>>>          :location :AliceWorkstation;
>>>>>>          :process :fileCreation ;
>>>>>>          :time "2011-06-15 18:00:02 UTC"  ]
>>>>>>     ) .
>>>>>>
>>>>>>
>>>>>>
>>>>>> ### New graph - Content changed
>>>>>>
>>>>>> :i0 a :DynamicResource ;
>>>>>>   :content [ :bytes "New York\nLos Angeles\n"  ] ;
>>>>>>   :name "/home/towns.txt" ;
>>>>>>   :creator :Alice ;
>>>>>>   :readBy (:Alice :Bob :Charles :David)
>>>>>>
>>>>>>
>>>>>> :i2 a :ViewResource ;
>>>>>>   :viewOf :i0 ;
>>>>>>   :name "/home/towns.txt" ;
>>>>>>   :creator :Alice ;
>>>>>>   :content [ :bytes "New York\nLos Angeles\n"  ] .
>>>>>>
>>>>>> :i2Provenance a :ProvenanceResource ;
>>>>>>   :provenanceOf :i2 ;
>>>>>>    :account :FileSystem ;
>>>>>>    :processes (
>>>>>>       [  :agent :Alice ;
>>>>>>          :location :server1 ;
>>>>>>          :process :fileCreation ;
>>>>>>          :time "2011-06-15 18:00:03 UTC"  ]
>>>>>> # Lost as :FileSystem metadata only keeps last-modified
>>>>>> #     [   :agent :Alice ;
>>>>>> #         :location :server1 ;
>>>>>> #         :process :fileWrite ;
>>>>>> #         :time "2011-06-15 18:00:03 UTC"  ]
>>>>>>      [
>>>>>>          #  :agent :Bob;  - not recorded as only owner/creator is 
>>>>>> kept
>>>>>>          :location :server1 ;
>>>>>>          :process :fileWrite ;
>>>>>>          :time "2011-06-15 18:14:12 UTC"  ]
>>>>>>     ) .
>>>>>>
>>>>>>
>>>>>> So say there are additional mutable properties such as :readBy 
>>>>>> above -
>>>>>> would you consider those propagating into the view as mutable
>>>>>> properties? There could be another view over :i2 for the file before
>>>>>> it was read by Charles, where :readBy is an immutable property.
>>>>>>
>>>>>> The example graph above does not distinguish between mutable and
>>>>>> immutable properties - perhaps we shouldn't as they could be 
>>>>>> difficult
>>>>>> to find, identify and measure.
>>>>>>
>>>>>> Here :readBy is not kept by neither the log file or file system 
>>>>>> and is
>>>>>> a kind of conceptual property - it could be discovered by simply
>>>>>> asking everyone who could have read it, or inferred from traced file
>>>>>> usage, like if its sent in an email.
>>>>>>
>>>>>> -- 
>>>>>> Stian Soiland-Reyes, myGrid team
>>>>>> School of Computer Science
>>>>>> The University of Manchester
>>>>>>
>>>>>>
>>>>>> ______________________________________________________________________ 
>>>>>>
>>>>>> This email has been scanned by the MessageLabs Email Security 
>>>>>> System.
>>>>>> For more information please visit http://www.messagelabs.com/email
>>>>>> ______________________________________________________________________ 
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>
>>>> ______________________________________________________________________
>>>> This email has been scanned by the MessageLabs Email Security System.
>>>> For more information please visit http://www.messagelabs.com/email
>>>> ______________________________________________________________________
>>>>
>>>
>>>
>>
>

-- 
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, 20 June 2011 11:51:13 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Thursday, 26 April 2012 13:06:31 GMT