- From: Luc Moreau <L.Moreau@ecs.soton.ac.uk>
- Date: Mon, 20 Jun 2011 08:39:15 +0100
- To: public-prov-wg@w3.org
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 07:39:48 UTC