- From: Curt Tilmes <Curt.Tilmes@nasa.gov>
- Date: Wed, 14 Dec 2011 14:24:13 -0500
- To: <public-prov-wg@w3.org>
1. +1 2. +1 3. 0 I don't like 'event' or 'action' for an instantaneous thing. 'milestone' seems reasonable. (I will again not be able to call in to the Thursday telecon.) Curt On 12/09/2011 01:36 PM, Luc Moreau wrote: > 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 Wednesday, 14 December 2011 19:24:50 UTC