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RE: PROV-ISSUE-30 (name-for-bob): What name do we use for the BOB construct? [Conceptual Model]

From: Myers, Jim <MYERSJ4@rpi.edu>
Date: Mon, 25 Jul 2011 09:53:33 -0400
Message-ID: <B7376F3FB29F7E42A510EB5026D99EF2054689F8@troy-be-ex2.win.rpi.edu>
To: Luc Moreau <L.Moreau@ecs.soton.ac.uk>, <public-prov-wg@w3.org>
+1. I think our challenge in PIL is to recognize that there are no
distinctions in the model we're discussing between very long-lived,
highly mutable Bobs and very short-lived, highly constrained ones. I can
talk about 'Jim was born', I can distinguish between childJim and
adultJim, or naiveJim and educatedJim to talk about learning, or
hungryJim and fullJim - all of these are valid things to record
provenance about. Other than the 'unchanging idea of Jim' (I've heard of
'historical Lincoln' as being this type of unchanging view) which would,
by definition, have no provenance, PIL needs to be able to talk about
all the other types of Bobs. Some of those will look like snapshots, but
most don't. If Jim-with-a-license is the snapshot of me that was created
when I took my driver's test, it's one that lasts for tens of years....

I think we'll have much better luck explaining to the world if we start
by saying PIL provides a model to talk about the provenance of entities
which include all of the types of things you already give identifiers to
- people, documents, The Royal Society, etc. Then we point out that PIL
has made the modeling choice to treat change internal to an entity via
the definition of new entities that represent the original in specific
contexts - a document with a fixed content is modeled as a version of
that document, copies represent the same logical file in different
places, we define "They Royal Society in London during period X", or
"They Royal Society at its 300th meeting", if we want to describe its
evolution,  etc. Again, it is clear because that is already done -
versions and copies and FRBR expressions/manifestations are already
understood to be entities in common sense terms. The fact that some of
these look like a bit like  'snapshots' and that our examples can
include very odd entities (Jim-when-he-breathed-out-just -now) is just
due to the granularity and the subject of the examples getting to a
finer scale than we discuss in casual conversation, not due to a
difference in kind. (Entities that represent me before and after
breathing might be useful if we're in a medical context, but it is the
complexity of that context that makes tracking the provenance of such
non-traditional entities useful... our unease with such ephemeral
entities is really due to our unfamiliarity with the intricacies of
medicine that make it useful to distinguish them).

Assuming that there is  only one type of Bob -  if we start from the
terminology of snapshot, we'll have to explain how PIL is relevant to
people who want to describe the history of objects/things/entities. (I
have a file, it has an identifier, and to use PIL I have to create a new
identifier and think in terms of a snapshot of that file which is
somehow not the file, even in cases where I just want to talk about
unchanging content (my server generated a license file for customer X)).

(If one really thinks we should have PIL:entities and PIL:snapshots both
in the model - versus just one concept that has to be renamed from Bob -
then we have more challenges to explain the difference in terms of what
they can be used for in the model as well as to provide guidance on when
to use which concept - both hard when the world already mixes them
(versions are objects and they are snapshots of documents - what are
they in PIL?)


> -----Original Message-----
> From: public-prov-wg-request@w3.org [mailto:public-prov-wg-
> request@w3.org] On Behalf Of Luc Moreau
> Sent: Monday, July 25, 2011 4:39 AM
> To: public-prov-wg@w3.org
> Subject: Re: PROV-ISSUE-30 (name-for-bob): What name do we use for the
> construct? [Conceptual Model]
> The word 'Entity' should also be considered for the construct BOB.
> If we do so, the text 'characterized entity' should be replaced by
something else
> in the draft specification.
> Why not 'thing'?
> So, the text could become:
>   Section 4.
>   In the world (whether real or not), there are things, which can be
> physical, digital, conceptual, or otherwise, and activities involving
> things.
>   Words such as thing or activity should be understood with their
> informal meaning.
>   This specification is concerned with characterized things, that is,
> things and their situation in the world, as perceived by the asserter.
>   Section 5.1
>   An ENTITY represents an identifiable characterized thing.
> Luc
> On 07/24/2011 11:43 PM, Reza B'Far wrote:
> > First, for the record Khalid was the person suggesting Snapshot :)
> >
> > The way I've seen snapshot used commercially, it's fairly consistent
> > with the current definition of BOB.  There is some murkiness on both
> > sides (how "snapshot" is used commercially and I think we're still
> > iterating here on the definition of BOB, but may be that's close to
> > finalized).  However, I think they are close enough.  What I liked
> > about "Snapshot" is that its intuitive and is used in several
> > that I know of (content management, legal, configuration systems,
> > I've also seen use-cases in microfilm production by old-school
> > librarians).  Also, I think "Snapshot" offers a huge advantage that
> > it's neither explicitly linked to the entity nor its state.  And I
> > know the distinction between entity vs. entity's state and how
> > articulated has been in a lot of the discussions.  Using "Snapshot"
> > sort of obsoletes that discussion.
> >
> > On 7/24/11 12:57 PM, Stephan Zednik wrote:
> >> I am not partial to snapshot, partially because of the extensive
> >> functional usage of the term.  I have always associated a snapshot
> >> with a point in time, not a duration - but this may be an incorrect
> >> association.
> >>
> >> I am open to discussing it, but my initial inclination was negative
> >> towards it.
> >>
> >> Will we use the same definition as we have been using for BOB?
> >>
> >> --Stephan
> >>
> >> On Jul 24, 2011, at 9:52 AM, "Reza B'Far"<reza.bfar@oracle.com>
> >>
> >>> I second the term "Snapshot".  This term also has functional usage
> >>> in several commercial application categories used within roughly
> >>> same meaning.
> >>>
> >>> On 7/24/11 3:45 AM, Khalid Belhajjame wrote:
> >>>> Hi Stephan,
> >>>>
> >>>> Given the example you gave in your previous email, I think that
> >>>> "EntitySpanshot" or "Snapshot" should be fine, given that it
> >>>> reflect the fact that it is a description of an entity that holds
> >>>> for some period of time.
> >>>>
> >>>> Do you agree?
> >>>>
> >>>> khalid
> >>>>
> >>>> On 23/07/2011 20:24, Stephan Zednik wrote:
> >>>>> I do not feel that EntityInstance, EntityInstantiation, or
> >>>>> InstantiatedEntity make sense for the book ownership scenario,
> >>>>> any scenario modeling the provenance of changes in
> >>>>> of a physical object.
> >>>>>
> >>>>> To reiterate the example since I haven't committed it to a wiki
> >>>>> page yet.  Book X is an entity that represents a real world
> >>>>> object.  It can be put on a shelf, loaned to friends, damaged,
> >>>>> and/or destroyed.  It has important characteristics (condition,
> >>>>> ownership, location, etc) that may change over the life of the
> >>>>> book.  We may want to represent the provenance of the book as a
> >>>>> chain of ownership.
> >>>>>
> >>>>> |<----------------------------------------------------- Book X
> >>>>>
> >>>>> |<!------ Book X with owner A ---->|<----Book X with owner B
> >>>>> ---->|<---- Book X with owner A --------->|
> >>>>>
> >>>>> If a book changes ownership, is the "book with changed
> >>>>> a different EntityInstance?  A different InstantiatedEntity?  I
> >>>>> don't think what we current call a BOB is an 'instance of'
> >>>>> anything.  I think of it as a description of an entity that
> >>>>> for some time period (not necessarily given) for which
> >>>>> contextually important mutable characteristics of the the entity
> >>>>> are held to be known.
> >>>>>
> >>>>> --Stephan
> >>>>>
> >>>>> On 7/22/2011 5:29 AM, Curt Tilmes wrote:
> >>>>>> On 07/22/2011 03:43 AM, Khalid Belhajjame wrote:
> >>>>>>> The term "Snapshot" was suggested some time ago, and it seems
> >>>>>>> several people did like it.
> >>>>>>> We can also use the term "EntitySnapshot".
> >>>>>> Following from snapshot:
> >>>>>>
> >>>>>> EntityInstance
> >>>>>> EntityInstantiation
> >>>>>> InstantiatedEntity
> >>>>>>
> >>>>>> Curt
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>
> >>>>>
> >>>>
> >>>
> >
> --
> 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, 25 July 2011 13:54:02 UTC

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