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Re: PROV-ISSUE-203: Proposal to amend definition and usage of Plan in PROV-DM [prov-dm]

From: Stephan Zednik <zednis@rpi.edu>
Date: Thu, 15 Dec 2011 15:51:33 -0700
Cc: Provenance Working Group WG <public-prov-wg@w3.org>
Message-Id: <01200DDC-264E-4DF8-8AEC-F41B0EE4E9D8@rpi.edu>
To: Yolanda Gil <gil@isi.edu>

On Dec 15, 2011, at 3:19 PM, Yolanda Gil wrote:

> Hi Stephan,
> 
> What you propose makes a lot of sense to me.
> 
> In my view, a plan is not an agent.  It could be an entity (although see below).

I think a plan should be an entity because it would allow us to describe the provenance of the plan.

> 
> An agent can use/follow/apply a plan to generate an entity.  I would not give the plan any agency in the model, because in many applications the plan will have no more responsibility (or agency) for the result than the input data which are not treated as agents.
> 
> In the cases where the plan acts as an agent in some application then the model can be extended for that application to express that.

Right.  I did not want to make the strong statement that plans cannot be agents, because I could see software and workflows described as either plans or agents depending on what you are trying to say about them.

In RDF-speak:  I would say that being a plan does not entail agency or responsibility.  If a users sees an individual as both a plan and an agent, then it is the membership in the set of agents that entails agency and responsibility.

With RDF it seems sufficient to simply not state they are disjoint, and let users dual-type individuals if it fits their needs.  I am not sure what the solution would be in PROV ASN or a native non-RDF XML encoding.

> 
> So I see a plan as an entity that has some role in an activity.
> 
> Now, the kind of role that the plan plays is another good question.  In my view, "used" is not appropriate, because the agent is using the plan but the activity is not.  In that sense, the plan is kind of a meta-entity.

I agree.  The agent follows/uses/applies the plan in its involvement in the activity.  Could the plan be a qualifier on the agent - activity association?

> 
> I would say that we need to have hadPlan, but hadPlan is not a specialization of "used" or "wasAssociatiedWith".
> 
> I also think that we need to add agent to hadPlan.  I think two agents associated with the same activity may each follow a different plan to design different aspects of the activity.  So we could say that hadPlan MAY specify what agent used that plan.

I completely agree :-)

--Stephan

> 
> Yolanda
> 
> 
> 
> 
> On Dec 15, 2011, at 11:52 AM, Provenance Working Group Issue Tracker wrote:
> 
>> 
>> PROV-ISSUE-203: Proposal to amend definition and usage of Plan in PROV-DM [prov-dm]
>> 
>> http://www.w3.org/2011/prov/track/issues/203
>> 
>> Raised by: Stephan Zednik
>> On product: prov-dm
>> 
>> Dear all,
>> 
>> I would like to suggest an amended definition and usage for plan in PROV-DM.
>> 
>> CONTEXT:
>> 
>> 1. The concept of plan is currently related to activity via a plan link, which is a specialization of an activity association record; as a consequence all plans are agents.
>> 
>> http://dvcs.w3.org/hg/prov/raw-file/default/model/ProvenanceModel.html#record-planLink
>> 
>> 2. This means that according to the definition of agent at http://dvcs.w3.org/hg/prov/raw-file/default/model/ProvenanceModel.html#section-entity-activity-agent, plans 1) take an active role in an activity and 2) can be assigned some degree of responsibility for the activity taking place.
>> 
>> 3. The relation between agents and the plan that guides their actions is not explicit in PROV-DM.  We could infer that all agents involved in an activity act according to the activity's linked plan, but this prevents us from describing an activity were multiple agents act guided by different plans.
>> 
>> PROPOSAL 1: Amend the definition of plan in PROV-DM to:
>> 
>> "In the context of PROV-DM, a plan should be understood as the description of a set of actions or steps intended by one or more agents to achieve some goal."
>> 
>> PROPOSAL 2: Amend plan link record such that it is not a specialization of an activity association record.
>> 
>> Comment: I do not think we should define all plans as agents.  By our existing definition a plan is a "set of actions or steps ... to achieve some goal."  It is a description (usually in the form of a document) of the action or actions an agent should take to achieve a desired goal.
>> 
>> As a description of the actions an agent should take, it does not make sense for a plan to have responsibility.  The responsible party for a plan (e.g. owner, creator) could have some responsibility for the outcome of the activity, but the description of the "set of actions or steps intended to achieve some goal" would not.
>> 
>> A plan without an agent is (generally) inert.  Something must follow/execute the plan for there to be action.  A recipe is inert - bread is made by the baker.  Driving directions are inert, a driver must control the vehicle from the trip's point of origin to its destination.  If driving directions are incorrect, it would be the source of the driving directions (e.g. Google Maps) that would bear responsibility for the failure of the activity to result in the desired objective.
>> 
>> Software and especially workflows are a fuzzy area; you can reasonably define any software as a document of steps that a microprocessor is capable of executing.
>> 
>> To allow users to record provenance in a way that is natural to them I suggest we not define plans and agents as disjoint, but I do not think we should define all plans as agents.
>> 
>> PROPOSAL 3: Amend plan link record such that it can express which agents in the activity are following the plan.
>> 
>> PROPOSAL 4: We should define a relation to describe the responsible party for a plan.
>> 
>> --Stephan
>> 
>> 
> 
> 
> 
Received on Thursday, 15 December 2011 22:52:25 UTC

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