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Proposals to vote on related to 'event': deadline Dec 14th midnight GMT

From: Luc Moreau <L.Moreau@ecs.soton.ac.uk>
Date: Fri, 09 Dec 2011 18:36:48 +0000
Message-ID: <EMEW3|f60544cd45c3c79e5165c84ebba974a7nB8IbG08L.Moreau|ecs.soton.ac.uk|4EE25540.1040306@ecs.soton.ac.uk>
To: Provenance Working Group WG <public-prov-wg@w3.org>
Dear all,

Several of you, including Satya, Tim and Jim have raised various
concerns about events.  Here are some proposals to tackle these
concerns in prov-dm WD3. Can you express your support in the usual
way, we will confirm the outcome at the next teleconference.

CONTEXT:

1. The concept of event as defined in prov-dm is instantaneous. On the
    other hand, other ontologies define the concept of event, e.g. LODE
    [1], as not instantaneous. This causes confusion, and risks
    hampering adoption.

2. The prov-dm document (WD2) is defining 'generation' in a
    conflicting manner.  On the one hand, in [2], it states that
    generation is an event, so is instantaneous.  On the other hand, in
    [3], it states that completion of generation is the event.

In a generation, what we care about is the point at which the entity
becomes available for consumption by others.  Before that, it's not an
entity yet (or it is not this entity being generated).  So, calling
the whole of generation an event (forget the choice of word for now)
is not what was intended.  The event is the point at which generation
is complete.

This is actually nice reflected in Olaf and Jun's provenance
vocabulary [4], where they have a similar concept, called Data
Creation defined as:

     DataCreation is a class that represents the completed creation of a 
data item.


Note the choice of word *completed*.

PROPOSALS:


We therefore propose to change the definition of Generation [2] as
follows.
- With proposals 1 and 2, resolve the conflicting definitions around 
generation (and use) in prov-dm.
- With proposal 3, adopt another name for event.



PROPOSAL 1. Adopt the following Definition for generation.
/In PROV-DM, a generation record is a representation of a
world event, the completed creation of a new entity by an
activity. This entity did not exist before this event; this entity is
available for usage after this event./


Comment: With this, we are not saying that creation of an entity is
the event, it's the completed creation that is an event.  It's also
also fine, I believe, to regard this as instantaneous.  Also, if
somebody wants to model the actual creation, it is also fine, they can
use activities for that.

For usage, we would take a similar approach. In the provenance
vocabulary, they use the completed access to a data structure, but
this is not right for what we want. Instead:

PROPOSAL 2. Adopt the following Definition for usage.
/In PROV-DM, a usage record is a representation of a world
event: the start of an entity consumption by an activity. Before this
event, this entity was not consumed or used in any form or shape by
the activity, totally or partially.
/
Comment: These definitions are now exactly in line with those in [3].


/PROPOSAL 3. Replace the word event by action./

Comment: So, prov-dm would define four actions: entity
generation/entity usage/activity start/activity end, which are all
instantaneous.  These actions would have "effects" on the system in
the sense that they change the entities and activities it contains.

Assuming proposal 3 is adopted, obviously, the text of proposals 1 and
2 would use the word 'action'.


Can you express your support, or counter-proposals, by Wednesday 
midnight GMT.
Assuming there is support, we would incorporate all these changes before 
XMas.

Best regards,


Luc

[1] http://linkedevents.org/ontology/
[2] 
http://dvcs.w3.org/hg/prov/raw-file/default/model/ProvenanceModel.html#dfn-Generation
[3] 
http://dvcs.w3.org/hg/prov/raw-file/default/model/ProvenanceModel.html#types-of-events
[4] http://trdf.sourceforge.net/provenance/ns.html#sec-DataCreationClasses
Received on Friday, 9 December 2011 18:37:42 GMT

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