[Modeling] Modeling an Agent Class- composition

Dr. Hong Zhu hzhu@brookes.ac.uk
Thu, 26 Jun 2003 11:30:01 +0100

Hi, Gerd and All,

I am NOT saying UML 2's definition is good. I believe that its weakness is
well known in the academic circle. What I am saying is that we need more
types of part-whole relations in AUML and that should be more clearly

Best regards,

> And contrary to Hong's appeal, we cannot rely on the UML2 spec for
> the semantics of aggregation/composition (especially wrt lifetime
> dependency), because it is unclear/confused and not well-defined.
> They say themselves:
> -----------------
> Semantic Variation Points (p.40 of the current UML2 document)
> The precise lifecycle semantics of aggregation is a semantic
> variation point.
> Semantic Variation Points (p.75 of the current UML2 document)
> Precise semantics of shared aggregation varies by application
> area and modeler.
> ------------------
> So we better rely on well-justified theories of the part-whole
> relationsip, such as sketched in my paper
> Towards Ontological Foundations for UML Conceptual Models
> http://tmitwww.tm.tue.nl/staff/gwagner/ODBASE-2002.pdf
> which is also a recommended reading in OMG's RFP for an Ontology
> Definition Metamodel.
> -Gerd
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