[Modeling] Modeling an Agent Class- register your opinion

Fri, 20 Jun 2003 13:13:32 +0200

Dear Hong

Why don't you describe complex agents like departments as CompoundAgents,
and a CompoundAgent as an aggregate of Agent? Some way or the other the word
Caste to me has the wrong flavour. Also I miss the notion of Agent in your
meta model.

When you simply use the word Agent as the class name of the class Agent you
can produce a meta model in UML. Using UML as the modelling language does
not mean that the behaviour of agents necessarily has been limited to OO.

Regards

Frits

----- Original Message ----- 
From: "Dr. Hong Zhu" <hzhu@brookes.ac.uk>
To: "Joaquin Peña" <joaquinp@us.es>; "'Wagner, G.R.'"
<G.R.Wagner@tm.tue.nl>; "'James Odell '" <email@jamesodell.com>;
"'ModelingTC '" <modeling@fipa.org>
Sent: Friday, June 20, 2003 10:04 AM
Subject: Re: [Modeling] Modeling an Agent Class- register your opinion

>
>
> ----- Original Message ----- 
> From: "Joaquin Peña" <joaquinp@us.es>
> To: "'Dr. Hong Zhu'" <hzhu@brookes.ac.uk>; "'Wagner, G.R.'"
> <G.R.Wagner@tm.tue.nl>; "'James Odell '" <email@jamesodell.com>;
> "'ModelingTC '" <modeling@fipa.org>
> Sent: Friday, June 20, 2003 8:43 AM
> Subject: RE: [Modeling] Modeling an Agent Class- register your opinion
>
>
> > Are you think in employees and departments as different agents?
> >
>
> Yes, an employee is a different agent from a department, although they are
> both agents.
>
> > I'm agree with you: part-whole relationship in UML is not
> > adequate. I see this relation as an "use relation" of a resource.
> > That if one of the parts is destroyed, this use is finished.
> >
>
> I would not call it 'use relation'. In CAMLE language, we now call it
> 'congregation' to indicate that the whole is an agent that is formed by a
> set of agents gethered together.
>
> Hong
>
>
> > Joaquin Peña
> >
> >
> > > -----Mensaje original-----
> > > De: modeling-admin@fipa.org [mailto:modeling-admin@fipa.org]
> > > En nombre de Dr. Hong Zhu
> > > Enviado el: viernes, 20 de junio de 2003 9:31
> > > Para: Wagner, G.R.; James Odell ; ModelingTC
> > > Asunto: Re: [Modeling] Modeling an Agent Class- register your opinion
> > >
> > >
> > > Gerd,
> > >
> > > The point is: the destroying of the whole (i.e. a department)
> > > cause the parts (i.e. the members) to lost its class
> > > membership to an 'agent class' (i.e. member of the
> > > department). What I am saying is that, the definition of
> > > part-whole relationship in UML in terms of shareability is
> > > not adequate. Even shareability plus lifetime cannot define
> > > the kind of part-whole relationship we need to deal with
> > > agent's part-whole relationships.
> > >
> > > I agree with you that, in agent-orientation, shareability
> > > does not imply lifetime dependency. However, I think, in
> > > object orientation, shareability does imply lifetime
> > > dependence. Because, if a part object is not shareable, then
> > > when the whole object is destroyed, the part objects become
> > > garbage. It life is then also finished. Am I right?
> > >
> > > -Hong
> > >
> > > ----- Original Message ----- 
> > > From: "Wagner, G.R." <G.R.Wagner@tm.tue.nl>
> > > To: "Dr. Hong Zhu " <hzhu@brookes.ac.uk>; "Wagner, G.R."
> > > <G.R.Wagner@tm.tue.nl>; "James Odell "
> > > <email@jamesodell.com>; "ModelingTC " <modeling@fipa.org>
> > > Sent: Thursday, June 19, 2003 5:57 PM
> > > Subject: RE: [Modeling] Modeling an Agent Class- register your opinion
> > >
> > >
> > > > > The relationship between the department and it members is
> > > different
> > > > > from composite in UML, because the agent is still alive after the
> > > > > owner is destroyed. It is also different from aggregation because
> > > > > the destroy of the owner (the department) affects the
> > > behaviour of
> > > > > the member agents
> > > (they
> > > > > lost the membership of department members and the associated
> > > > > capability
> > > and
> > > > > accessible resources). If an object is a part of another
> > > object as
> > > > > an aggregate, the destroy of the owner will not affect the part
> > > > > object's membership to any class, so does not affect its
> > > behaviour.
> > > >
> > > > Hong,
> > > >
> > > > again, the difference between aggregaion and composition is
> > > simply the
> > > > property of shareable parts. The property of lifetime
> > > dependency you
> > > > refer to is orthogonal to this.
> > > >
> > > > Obviously, in your example, there is an aggregation relationship
> > > > between the members of a department  and the department (because a
> > > > member can be also a member of another department, i.e.
> > > members can be
> > > > shared). An aggregation relationship does not imply anything wrt
> > > > lifetime dependency and it does neither imply that it would
> > > not affect
> > > > its parts. These are additional, othogonal issues.
> > > >
> > > > So, your conclusion that we need a "third" part-whole
> > > relationship is
> > > > unfounded.
> > > >
> > > > -Gerd
> > > >
> > > >
> > > > > ----- Original Message -----
> > > > > From: "Wagner, G.R." <G.R.Wagner@tm.tue.nl>
> > > > > To: "Dr. Hong Zhu " <hzhu@brookes.ac.uk>; "James Odell "
> > > > > <email@jamesodell.com>; "ModelingTC " <modeling@fipa.org>
> > > > > Sent: Tuesday, June 17, 2003 9:03 PM
> > > > > Subject: RE: [Modeling] Modeling an Agent Class- register
> > > your opinion
> > > > >
> > > > >
> > > > > > > The part-whole relationship between agents are also
> > > different:
> > > > > > > The aggregation relationships between the whole and part is
> > > > > different in
> > > > > > > agent classes from that in object class. In object
> > > orientation,
> > > > > there
> > > > > are two
> > > > > > > types of whole-part relations:
> > > > > > > (1) composition, in which the lifespan of the whole
> > > and the part
> > > > is
> > > > > the
> > > > > > > same, and (2) aggregation, in which the lifespan of the whole
> > > > > > > and
> > > > > part
> > > > > > > is independent. Having two whole-part relations is inadequate
> > > > > > > for agent-orientation due to agent's autonomous behaviour. For
> > > > example,
> > > > > we
> > > > > > > have a agent which represents a department in a
> > > university, and
> > > > > > > a
> > > > > number
> > > > > of
> > > > > > > agents as members of the department. When the department is
> > > > > destroyed,
> > > > > > > the members as individuals still exist, but their class
> > > > > > > membership
> > > > > as
> > > > > the
> > > > > > > member of the department are lost.
> > > > > >
> > > > > > This is a misunderstanding of the UML aggregation concept.
> > > > Composition
> > > > > > is defined as a "non-shareable" aggregation, and not
> > > via lifetime
> > > > > dependency.
> > > > > > There are some misleading remarks about lifetime
> > > dependency in UML
> > > > > 1.4.
> > > > > > Lifetime dependency is implied in aggregations with inseparable
> > > > parts.
> > > > > > It's not related to shareability. Please see my
> > > ODBASE'2002 paperr
> > > > on
> > > > > > ontological foundations of UML (on my homepage) for further
> > > > > explanattions.
> > > > > >
> > > > > > Of course, all general ontological isssues of the part-whole
> > > > > relationship
> > > > > > apply to all things, no matter if they are agents or objects.
> > > > > >
> > > > > > -Gerd
> > > > > >
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