From owner-shlaer-mellor-users@phoenix.projtech.com Wed Aug 22 18:03:46 2001 Received: from phoenix.projtech.com (209-234-139-66.twtelecom.net [209.234.139.66] (may be forged)) by saturn.cs.uml.edu (8.11.0/8.11.2) with ESMTP id f7MM3id429132 for ; Wed, 22 Aug 2001 18:03:44 -0400 (EDT) Received: (from majordom@localhost) by phoenix.projtech.com (8.9.3+Sun/8.9.1) id OAA04343 for s-m-users-outgoing; Wed, 22 Aug 2001 14:13:35 -0700 (MST) X-Authentication-Warning: ns.projtech.com: smap set sender to using -f Message-ID: <20010822211307.46700.qmail@web14606.mail.yahoo.com> Date: Wed, 22 Aug 2001 14:13:07 -0700 (PDT) From: Bob Dodd Subject: Re: (SMU) Many Domains Question To: shlaer-mellor-users@projtech.com In-Reply-To: <000e01c12067$bf059920$6998be84@hmeyersonvl400> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: owner-shlaer-mellor-users@projtech.com Precedence: bulk Reply-To: shlaer-mellor-users@projtech.com Errors-To: owner-shlaer-mellor-users@projtech.com X-Status: Status: RO Bob Dodd writes to shlaer-mellor-users: -------------------------------------------------------------------- This came to mind because of the discussion on 3D domain charts: I suspect a lot of people come to grief on domain charts, but then we don't seem to have many rules to help guide people. We have our 72 OOA rules in the paper from Neil Lang, but they are specific to an individual domain, we don't seem to have an equivalent list published for the domain chart itself... For what it's worth, I would suggest as a start, that we at least try to cover the basic math which could go something like: A perfect domain chart is one in which can be represented as a directed graph where: (i) if considered to be undirected, the graph is connected. (ii) there is at least one vertex which is connected by edges which originate from the vertex, but which is connected by no edges that terminate at that vertex. (iii) there exists no cut set of the graph that contains a Hamiltonian Circuit. (iv) there is one and only one edge connecting any two vertices. (v) the weight of every edge is 1 (one). It's very easy to argue with the rules in my theory of the 'perfect' domain chart (and it doesn't begin to answer sizing and complexity rules, though it gives a language to express them: tree depth, longest path, fan-in, fan-out etc.) but it does force the issue of what represents at least a syntactically correct domain chart e.g. * Which bridges (if any) can be omitted? e.g. bridges to architecture and implementation domains? * Can large domain charts ever be drawn as smaller parts (i.e. mulitple diagrams) that repeat the names of domains and repeat bridges expressed on other parts (e.g. as we do with subsystems within a domain), or is there only one single domain chart? * Can you ever have two service domains that provide services to each other, however indirect? (i.e. the Hamiltonian Circuit exclusion rule) Sorry, maybe this sounds a bit picky, but imagine trying to define an XML schema/DTD to describe a domain chart so that you can export and import S-M models between different vendor's CASE tools. S-M is very precise within a domain, but you can see the problems we have in writing a validating XML parser for the domain chart... Clearly, there are also rules about domain content / subject matter, and complexity (which is where this thread came from), but we need to start somewhere, and I suggest that somewhere is the syntax rules and a language in which to express them. /bob dodd --- Howard Meyerson wrote: > "Howard Meyerson" writes to > shlaer-mellor-users: > -------------------------------------------------------------------- > > Hi Folks, > > I haven't been on this list in a while, but now I'm back in OOA land! > > As we look ahead in the current project on which I am working, our > analysis > may result in 40-50 (or more?!) domains. We are concerned that > number is > too big. Obviously, we can look for domains that could be combined > or > changed into subsystems. I'd like to know general guidelines for > number of > domains and how to deal with complexity in the domain diagram. The > domain > diagram (and most other SMOOA diagrams) is supposed to be flat, but > that can > make it hard to view the whole picture at once. We have considered > dividing > the domain diagram up into multiple views. > > What suggestions can the SMOOA crowd give? > > Thanks, > Howie Meyerson > Varian Medical Systems > Howard.meyerson@varian.com > > __________________________________________________ Do You Yahoo!? Make international calls for as low as $.04/minute with Yahoo! Messenger http://phonecard.yahoo.com/