[Modeling] Class Diagram Specification

sehl mellouli sehl.mellouli@ift.ulaval.ca
Thu, 05 Jun 2003 16:44:14 -0400

My answer is below:

Wagner, G.R. wrote:
>>Marc-Philippe wrote:
>>"the first level is the one, we always consider
>>knowledge, acquaintances, roles, groups, protocols, etc. and we have a
>>second level where we describe those elements in a 
>>"computable" manner,
>>see the example above, the first level is at design level, the second
>>one is at implementation level, and above all, we need to give recipes
>>to help designers moving from the first level to the second one."
>>and in level 1, we deal with roles, groups, etc. And to this level I 
>>have pointed in my previous messages.
>>AUML agent diagram is in level 2, because we have implementation 
>>I hope it is clear now :)
> Yes, it's clear, but you should better read my message before 
> you reply to it: at both of your levels (and in general, we
> distinguish between 3 levels, as in the MDA), we can/should
> use UML class diagrams! UML class diagrams are a powerful
> language for conceptual modeling of real world domains that
> include agents and objects.
> Do you really suppose that you can come up with a better 
> conceptual modeling language than UML class diagrams (or
> some extension of it)? 

I have well understood what you said in previous messages. Now, if we 
limit our self to UML class diagram, if we don't bring any extension to 
it, if we see agents as attibutes and functions, so why we need agents? 
  We have classes and that's it. So, we need models that are specific to 
agents. We can start from UML class diagram and extend it. For example, 
two roles can share knowledge. How can we represent that two roles share 
knowledge in UML class diagram? Inheritance? I don't think so. a new 
streotype? in that case all can be thought as streotype!!. the notion of 
knowledge share must be dealt with in the design phase so that the 
developer knows that there is a knwoledge share between two roles. So 
any agent that will play these roles must share knowledge. So we have to 
extend UML class diagram to deal with this relation.

there are a lot of other relations between roles that cannot be 
represented in UML class diagram: social relations, control relation, etc...

My point of view is: we have to use existing modeling techniques but we 
have to extend them. How? let's think about.

Best regards,

> -Gerd

Mellouli Sehl
Computer Science Engineer
Information Systems Administration MBA
Computer Science Phd Student
Université Laval, Québec, P.Q, Canada
Tél: bur (418) 656-2131 (4704)
Home page: http://www.ift.ulaval.ca/~mellouli