[Modeling] agents vs actors

Marian Nodine nodine@research.telcordia.com
Thu, 18 Sep 2003 09:02:53 -0500

This is a multi-part message in MIME format.
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit

James --

Interestingly enough, none of these three definitions is related to what
I think an actor is. Here is my rough draft of a two cents worth:

Start with activities. An activity is a coherent unit of work. An activity has
a type.

Now, a role describes a set of related types of activities that may be
performed by the same actor (e.g. a hostess can pour coffee, or greet people.)

A resource is an external entity that may be either required by or used by some
activity (e.g. a printer, a document, an agent, a person).

An actor is an intelligent resource that has the capacity to initiate, manage,
and/or control activities of given types.

Actors have capabilities. These capabilities define the roles that the actor
can fill (e.g. I can be a coffee pourer, I can be a people greeter, I can be a
hostess.). An agent may be assigned to do a particular activity if the activity
has a type that may be performed by one of the roles that are within the
agent's capabilities. (modulo the fact that the agent may be able to learn new

-- Misty

James Odell wrote:

> Vivek ,
> This discussion would benefit greatly by a clarification of what an actor
> is. The following three sentences are all taken from the UML2.0 spec:
> "An actor specifies a role played by a user or any other system that
> interacts with the subject."
> "An Actor models a type of role played by an entity that interacts with the
> subject"
> "Actors model entities external to the subject. Each actor represents a
> coherent set of roles that users of the subject can play when interacting
> with it. When an external entity interacts with the subject, it plays the
> role of a specific actor."
> As you see, the three sentences define actor completely different: a role, a
> type of role and an entity/set of roles - the last one is the Semantics
> text. (This should in fact be registered as an FTF issue to be fixed in the
> coming year.)
> Cheer,
> Jim
> On 9/17/03 12:36 PM, "Vivek Kumar Singh" indited:
> > Hello all,
> >
> >
> > I'm a student of Mtech ICT, DA-IICT, india. I'm working on modelling of
> > a project on agents. But I'm finding it very diffiult to categorize my
> > agents as either actors or use cases. According to books on UML
> > modeling, and actor is an external entity interacting with our system.
> > If I consider this then agents can't be actors. But also it is said
> > that actor can initiate processes (use cases). So according to this, my
> > agents become actors.
> >
> > My project idea is to develop intelligent agents for every student in
> > institution and also to have intelligent library agents. Then students
> > can just order their agents to search for a book on a particular topic.
> > The agents who will be knowing about his master's interests and
> > knowledge level and will intelligently search for most suitable book
> > for his master from a big list of books. The library will also have
> > intelligents on particular subjects. The project also have many adjunct
> > features.
> >
> > But the problem is identifying agents as actors or use cases. I've seen
> > extended form of UML for this, but what can be done with UML's present
> > form and Rational rose. Kindly give suggestions.
> >
> > With regards,
> > Vivek Kumar Singh
> >
> >
> >
> > Vivek Kumar Singh
> > Mtech ICT, DA-IICT
> > Gandhinagar
> > MOB : 09426374152
> > http://intranet.da-iict.org
> > _______________________________________________
> > Modeling mailing list
> > Modeling@www.fipa.org
> > http://fipa.org/mailman/listinfo/modeling
> _______________________________________________
> Modeling mailing list
> Modeling@www.fipa.org
> http://fipa.org/mailman/listinfo/modeling

Content-Type: text/x-vcard; charset=us-ascii;
Content-Transfer-Encoding: 7bit
Content-Description: Card for Marian Nodine
Content-Disposition: attachment;

org:Telcordia Austin Research Center
title:Senior Research Scientist
fn:Marian Nodine