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Re: PROV-ISSUE-187: Section 5.2.2 (PROV-DM as on Nov 28) [prov-dm]

From: Satya Sahoo <satya.sahoo@case.edu>
Date: Wed, 7 Dec 2011 20:38:54 -0500
Message-ID: <CAOMwk6yhT08cv_gx2KkFkeYCtx_iOLXK50KjiDsL6eczg6tz8w@mail.gmail.com>
To: Luc Moreau <L.Moreau@ecs.soton.ac.uk>
Cc: public-prov-wg@w3.org
Hi Luc,
Apologies for my delayed reply to your earlier mail. I have responded to
your comments in ISSUE 101.

One response is interleaved:

To address this specific example, I am not sure what you are trying to
> express, since the attribute status
> is application specific. But for example, you could write
> activity(a1, [status="composing text", status="uploading attachment",
> status="sending", status="sent"])
> meaning that the activity a1 had a status with one of the possible values
> "composing ...", "uploading", ..." sent".
> Ok, so the values of an attribute can be assigned from a list of possible
values? Then the current requirement that attribute values have to hold "...
 for its whole duration..." is not a requirement.

> The duration is given by the interval between start and event.
> To some extent, an entity interval or an activity interval are opaque, we
> just know that some attributes
> hold for the duration.
> If you want to describe that something changes in an activity. Say it was
> on hostA, and then on hostB,
> then, you need to express this as two separate activities.

I believe this is an application-dependent requirement whether an activity
running on hostA is different or same when it is running on hostB. For
example, a Tomcat daemon running on port8080 or port80 will be considered
the same activity by a user browsing an online book store.

> Likewise, if you want to say running, paused, running,
> you also have to have separate activities.
In case of an OS, the thread will have the same process id across its
different states.

> What definition would you like to see for type? Intentionally, it's open
> ended, so that we don't constraint
> application to using specific typing approaches.
> Further information is also available in the type attribute in
> http://dvcs.w3.org/hg/prov/**raw-file/default/model/**
> ProvenanceModel.html#record-**attribute<http://dvcs.w3.org/hg/prov/raw-file/default/model/ProvenanceModel.html#record-attribute>

I raised the issue since it matches the rdf:type attribute already defined
and well known in the Web community it will be a source of confusion
prov:type vs. rdf:type. The example given in Section 5.5.1 does not clarify
how to interpret it. If we want it to be open-ended, then do we need to
make it a reserved DM attribute?



> Luc
> On 12/07/2011 01:53 AM, Provenance Working Group Issue Tracker wrote:
>> PROV-ISSUE-187: Section 5.2.2 (PROV-DM as on Nov 28) [prov-dm]
>> http://www.w3.org/2011/prov/**track/issues/187<http://www.w3.org/2011/prov/track/issues/187>
>> Raised by: Satya Sahoo
>> On product: prov-dm
>> Hi,
>> The following are my comments on Section 5.2.2 of the PROV-DM as on Nov
>> 28th 2011.
>> Section 5.2.2:
>> 1. "attributes: a set of attribute-value pairs [ attr1=val1, ...],
>> representing other attributes of this activity that hold for its whole
>> duration."
>> "an activity record's attribute remains constant for the duration of the
>> activity it represents."
>> Comment: I have raised this issue before - why does the attribute values
>> of an activity have to hold for its whole duration? Why is this constraint
>> necessary or enforceable?
>> If emailing is an activity a0 with attribute "status", then how do we
>> represent [status="composing text"], [status="uploading attachment"],
>> [status="sending"], and [status="sent"]?
>> In addition, what does "duration" of activity mean - the time when it is
>> "active" or between its "start event" and "end event"? What about "paused
>> event"?
>> 2. "The attribute type is a reserved attribute of PROV-DM, allowing for
>> subtyping to be expressed."
>> Comment: Exact definition of "type" is absent?
>> Thanks.
>> Best,
>> Satya
> --
> 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<http://www.ecs.soton.ac.uk/~lavm>
Received on Thursday, 8 December 2011 01:39:23 UTC

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