RE: Where are we at? Where to from here?



RE: Where are we at? Where to from here?

From: Jrn Guy S <jgsuess_at_itee.uq.edu.au>
Date: Mon, 15 May 2006 09:51:48 +1000
Message-ID: <000c01c677b1$61017500$4e406682@itee.uq.edu.au>
Precise UMLeers,

In response to Greg's original post, attached you will find a small figure,
showing statistics on the growth of UML. If we perceive the UML as a
(software) system, we will find that its complexity has greatly increased
over the years. This affects usability on a theoretical and practical level.

(cmp. Papers likes
http://www.planetmde.org/wisme-2005/NavigatingTheMetaMuddle.pdf
and 

@inproceedings{DBLP:conf/uml/MaSZJ04,
  author    = {Haohai Ma and
               Weizhong Shao and
               Lu Zhang and
               Yanbing Jiang},
  title     = {Applying OO Metrics to Assess UML Meta-models.},
  booktitle = {UML},
  year      = {2004},
  pages     = {12-26},
  ee        =
{http://springerlink.metapress.com/openurl.asp?genre=article{\&}issn=0302-97
43{\&}volume=3273{\&}spage=12},
  crossref  = {DBLP:conf/uml/2004},
  bibsource = {DBLP, http://dblp.uni-trier.de}
}
)

In other words, with a body of specification that large, consistency is
almost impossible to achieve. Attempts for UML 1.4 were already seriously
hampered by the size.

In the same vein, practicability is even harder, because lack of
specification forces implementers to interpret the standard, rather than
adopt it. The result is not UML, but VML - Vendor Modelling Language.

This affects the perceived value of models as assets that are independent of
a vendor. If my core business ideas would be placed at the mercy of somebody
else's meta-model/storage format, would I commit to such an offer, for a
limited productive gain?

As criticism without alternative is unproductive, I would propose to
untangle the web in the following way.

* Abort work on the existing UML standard 2.0. 
* Focus work on well understood, open, and minimal systems, such as EMOF
(the basis for IBM EMF). Start with a class-based abstraction, such as
Object-Z (One option!)
* Set up a research-based forum of focus, that is independent of the OMG,
like the OCL Portal
(http://web.inf.tu-dresden.de/~s9600916/OCL-Portal/index.php)
* Build minimal metamodels of particular interest for UML's parts, describe
their conditions of composition into a new metamodel.

This approach could provide the following advantages/ remedy the following
shortcomings:

* Research impact is immediate, and the changes made to a commonly
maintained standard are traceable. The counterexample is the current OMG
process, were the proceedings of the workgroups cannot be observed. Only
selected results are published at larger intervals.

* Research is rewarding, because contributions can be ascribed to research
institutions and individuals. In the current process, researchers may, as in
the case of the OCL standard, contribute significantly to the work, but do
not receive a mention in the result. As this is uneconomical for the
researcher in the promotion of their own work, they withdraw from the
effort, leaving it weakened.

* Results are free. In the current situation, OMG publications are
copyright-protected content of the same-named company. Consequently, each
person that wants to use terms branded by the OMG or reference the products,
has to go through a legal process. This stifles innovation. In one concrete
case known to me, a researcher wanted to produce a public HTML version of
the UML standard, to make it more accessible. The request was denied by the
OMG.

The last argument I would like to add is of a moral nature: If we do not
provide a unifying basis to the UML and MOF, there will be no common use as
explained above. Thus, the biggest shark is going to take the smaller fish
in the waters of modelling tools. Microsoft has already affected a change in
the naming of the UML conference from UML to MODELS. It will not be long
until the UML disappears from public perception and we will have to write
about 'Software Factories', 'DSLs' and their underlying formalisms. Quoting
one of Microsoft's Researchers:

"So I don't see UML as a central part of the software factory/DSL story."
(cmp. http://blogs.msdn.com/stuart_kent/archive/2004/09/29/235482.aspx )

I hope that model-driven processes will not become intellectual capital of
one institution. Digressing from the OMG-standard to avoid such a situation
seems to be a small price to pay.

Model on!

Jrn Guy S

Research Officer

Room 350, General Purpose South Building (building 78) Division of Systems
and Software Engineering School of Information Technology and Electrical
Engineering The University of Queensland Queensland 4072 AUSTRALIA

Phone: +61 7 3365 2883; Fax: +61 7 3365 4999

email: jgsuess@itee.uq.edu.au

-----Original Message-----
From: puml-list-request@cs.york.ac.uk
[mailto:puml-list-request@cs.york.ac.uk] On Behalf Of Greg O'Keefe
Sent: Sunday, 14 May 2006 19:01
To: pUML list
Cc: Greg O'Keefe
Subject: Where are we at? Where to from here?

Precise UMLeers,

I am interested to know your opinions of the state of play in making UML
precise.

I understand this list originated with a specific effort (MML) to give
foundations to UML using an object calculus based on that of Abadi and
Cardelli.  That became a bid for the UML 2 rfp, but it did not win. 
Perhaps the main players were discouraged by this, so now the list is
just a forum for technical questions and gripes.

Is it still a good idea to try to make UML precise?  

Can work outside the large IBM funded project have any influence?

Perhaps we should look instead to a new, well defined language, or
giving UML-like notation to an existing formalism? 

Let's revisit the big picture!

I look forward to reading your views,

Greg O'Keefe
-- 
Computer Sciences Laboratory
Research School of Information Sciences and Engineering
RSISE Building 115
The Australian National University
Canberra ACT 0200
Australia

T: +61-2-6125-8608
F: +61-2-6125-8824
E: greg.okeefe@anu.edu.au
W: http://rsise.anu.edu.au/~okeefe




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Received on Mon 15 May 2006 - 00:51:57 BST