Re: [soa-rm] On UML

["Gregory A. Kohring" <kohring@ccrl-nece.de>]

Hi,

As the one who raised the issue of using UML, let me clarify my
concerns. The main issue is whether to use a standard, formal modeling
language versus an ad-hoc, informal modeling language.  There are
two major advantages to of using a standard modeling language:

1) If it is a widely accepted standard language, then people can be
expected to know it and do not have to learn it first to understand
the model.

2) It allows you to compare different models for their compatibility;
a task which is very difficult if each party creates their own
modeling language to describe their model.

I nominated UML for the language to build our SOA-RM as it is a well
known modeling language.  The concept maps shown in documents like
those from the w3c, seem to me to be similar in conception to a UML
domain model; hence, they could be cast into UML without the need of
yet another informal modeling language. (Personally, I think we need
to move beyond domain models if we are to make any impact; but a
domain model makes a good starting point.)

Now I know many people do not like UML, because
it is quite a large language, but you do not need to use much of it
to create a reasonable domain model.

One way to move forward would be to create two parallel models, one
formal (using UML) and one informal (using Concept Maps). Initially
you would probably not notice the difference between the two, except
that they looked different when printed on paper. Later,
the UML model could be expanded to produce different views for
expert audiences. (I think we do need a model for experts with
more details than that contained in the model for non-experts.)


Cheers,

Greg


Duane Nickull wrote:
> My thoughts on UML and Concepts Maps are that it is best to start with 
> the simplest presentation (Concept map) and see if we have a firm need 
> for UML.  A concept map often groups many things that may not appear in 
> the same UML diagram which often make them easier to grok than UML.
> 
> The position paper Matt and I submitted uses the concept maps that we 
> used in the W3C Web Services Architecture document.  Concept maps are 
> easy to compose, however they can also be the death of a standard since 
> they are often very open ended.  It is very easy to keep adding concepts 
> until you get something that looks like the large concept map in the W3C 
> WSAG Technical Note.  UML, by comparison, is far more strict however 
> leads to multiple views of the same things in attempts to relay 
> information about them.
> 
> I encourage everyone to read the 3 different submissions so far into the 
> group to see how the concept/mind maps work and analyze how they can 
> also be open ended.
> 
> Some basic modelling conventions for keeping things simple are to use no 
> more than 5-6 concepts per model, then layer the more technical aspects 
> in UML.  You can use concept maps and UML to show architectural patterns 
> too.
> 
> Let's start with concept/mind maps to model "what" we are going to be 
> dealing with, then delve into whether or not we need UML based on that.
> 
> Duane
> 
> 


-- 
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G.A. Kohring
C&C Research Laboratories, NEC Europe Ltd.
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