Re: smaller example


The definitions of IVPT given below by Jim and Luc makes sense.
I didn't understand in the beginning why the properties changes from 
mutable to immutable.
In other words, I would have imagined that there is a fixed set of 
properties that are used for identifying a "thing", e.g., name of the 
file, and other properties that changes over time given rise to new IVPT 
of the initial Thing, i.e., file.
That said, I now understand the rational behind the need for changing 
mutable properties into immutable ones, namely the need to capture 
different level of abstractions, which I think Jim was pushing forward 
since the beginning of the discussions on resources :-)

That is to say that I support the proposal: +1 from me.

Thanks, khalid

On 13/06/2011 19:30, Myers, Jim wrote:
> FYI - Luc and I had a Skype call this morning to discuss a path forward
> on how to address invariance and we have tried to combine aspects of
> both alternatives from the working group discussion in a way that
> hopefully works and can gain consensus. A few more details below, but
> the general path is to model with one type of thing (ala IVP of T) but
> to push the definition of that type of thing to be independent of
> processes (ala IVPT). The question for the group is then whether this
> makes sense/looks like it helps/is consistent with other views/should be
> elucidated further, etc.
> Cheers,
>     Jim
> The following is my embellishment of what Luc and I discussed -
> hopefully still consistent with our discussion :-) I expect some further
> refinement will be needed to nail everything down.
> Definition of 'thing': In PIL, entities in the real world (described in
> terms of physical, digital, logical, conceptual, other vocabularies) are
> modeled as "things" that:
> * have an identity
> * model aspects of the entity's state as a set of properties of the
> "thing" that are invariant and considered integral to identity
> * model other aspects of the entity's state as a second set of
> properties that are mutable and able to change during the "thing"'s
> lifecycle, and therefore not integral to identity
> There are no assumptions that the sets of properties are complete as
> documented, or that the properties are independent/orthogonal of each
> other.
> Definition of "invariant view/perspective" (IVP):
> For A and B, both of which are "things", B is an  IVP of A iff
> * A and B represent the same entity/part of the real world at some
> instant in time (the set of properties they share must have identical
> values at that instant), and
> * there is/are mutable property(ies) of A that is/are correspond to
> immutable property(ies) of B (i.e. ones that are integral to B's
> identity)
> These definitions then have a number of implications:
> * If B is an IVP of A, they must have the same values for all immutable
> properties they have in common (for their entire existences...).
> * The distinction between A and B becomes relevant when one is
> discussing processes that affect the aspects of entity state represented
> by the subset of properties that represent the shift of some aspect of
> state from mutable in A to immutable in B. If B is an IVP of A at time
> t, B is an IVP of A is true for the whole interval between processes of
> this type.
> Etc.
>> -----Original Message-----
>> From: [mailto:public-prov-wg-
>>] On Behalf Of Luc Moreau
>> Sent: Monday, June 13, 2011 5:35 AM
>> To: Provenance Working Group WG
>> Subject: smaller example
>> Dear all,
>> On June 7th [1], we agreed on "In a first instance, to define the
> necessary
>> concepts that allow us  to express the provenance of an invariant view
> or
>> perspective on a thing".
>> Putting this in practice turns out to be difficult.
>> While the egg example is interesting, the scenario seems to evolve all
> the
>> time. Also, I thought that, in a first instance, we may want to look
> at things
>> that are digital, before seeing how our ideas extend to the
> non-digital world.
>> Obviously, we have our data journalism example, but we seem to ignore.
> I
>> think that we ignore it because:
>> - it does not focus on changing things
>> - it is not precise about how information is published/access,
>> - it is quite long
>> (I liked what Simon proposed for this example [2] and this inspired me
> here)
>> To unblock the situation, I have:
>> - drafted a smaller example [3], focusing on a file being updated
>> - tried to illustrate examples of IVPTs in this example
>> - highlighted an example of IVPT that I don't know how to handle.
>> In this example, it would be good to see
>> - where we have consensus
>> - where we have disagreement
>> - how we handle the outstanding example (i0) of IVPT
>> Feedback by email or on wiki welcome!
>> Cheers,
>> Luc
>> [1]
>> [2]
>> [3]
>> --
>> Professor Luc Moreau
>> Electronics and Computer Science   tel:   +44 23 8059 4487
>> University of Southampton          fax:   +44 23 8059 2865
>> Southampton SO17 1BJ               email:
>> United Kingdom           

Received on Thursday, 16 June 2011 11:31:00 UTC